Papers for Friday, Feb 27 2026

In this work, we explore constraints on the emergence and longevity of technologically intelligent civilizations in our Galaxy, considering the Fermi paradox. We argue that under optimistic assumptions about the probability of life and intelligence emerging on Earth-like planets, the absence of contact with extraterrestrial civilizations imposes limits on their lifespan. Our analysis suggests that if intelligent life is common, technological civilizations must be relatively short-lived, with lifetimes constrained to $\lesssim 5\times10^3$ years under our most optimistic scenario. Considering electromagnetic communication, we note that our current light cone encompasses the entire Galactic history over the past $\sim 10^5$ years, making the lack of detected signals particularly puzzling for long-lived civilizations. We emphasize that these results should be interpreted as upper bounds derived from the Fermi paradox, not as predictions of actual lifespans.

This study provides a detailed examination of the structural, astrophysical, kinematic, and dynamical properties of the open clusters COIN-Gaia 24, Czernik 24, FSR 0893, and UBC 74, which are located in the direction opposite to the Galactic center. Astrometric, photometric, and spectroscopic data from the Gaia Data Release 3 catalog were used to ensure a precise characterization of cluster members and their physical properties. Membership determination was performed using the UPMASK algorithm applied to a five-dimensional parameter space, yielding 116, 179, 238, and 387 likely members for each cluster, respectively. Structural parameters were derived by fitting King profiles to the radial density distributions of high-probability members. Astrophysical parameters were estimated through Bayesian Markov Chain Monte Carlo isochrone fitting based on PARSEC evolutionary models, complemented by spectral energy distribution analysis using ARIADNE. The resulting extinctions, distances, metallicities, and ages indicate that these are moderately reddened, intermediate-age clusters located between 1 and 3.5 kpc from the Sun. Mean radial velocities combined with Galactic orbital integrations computed with galpy show that all four clusters follow nearly circular, low-eccentricity orbits typical of thin-disc populations. All four OCs have dynamical relaxation times of 22-98 Myr. However, their ages exceed these times by several factors, particularly in Czernik 24, indicating that they are dynamically evolved systems, even though the calculated T_E values represent lower limits. The results confirm that these OCs serve as reliable tracers of the chemical and dynamical evolution of the Galactic thin disc.

We revisit black hole mass estimates for high-redshift broad-line AGNs discovered with JWST by jointly analysing their broad emission lines and their systematic non-detections in deep Chandra imaging. Building upon the self-shadowed, super-Eddington accretion flow framework and the coronal over-cooling prescription of Madau & Haardt (2024), we couple funnel-dependent Comptonization physics with slim-disc spectra from Kubota & Done (2019) and explore the resulting parameter space through a full MCMC inference. Using the sample analysed by Lupi et al. (2024) and Maiolino et al. (2025), we show that X-ray weakness - manifested as extreme bolometric corrections, suppressed 2-10 keV luminosities, and non-detections in the 0.5-5 keV Chandra band - naturally arises when the corona is confined and radiatively over-cooled inside a narrow super-Eddington funnel. The combined broad line+X-ray analysis yields strongly bimodal posteriors: either very massive, very low-Eddington black holes (physically disfavoured), or a population of low-mass ($\sim 10^{6}-10^{7} ~M_{\odot}$) black holes accreting at $f_{\rm Edd} \gg 1$. The latter solution is strongly preferred for nearly all objects and returns masses consistent with, or lower than, local $M_{\rm BH}-M_{\rm star}$ relations, mitigating the extreme mass ratios implied by single-epoch virial estimators. The predicted intrinsic spectra are redder and exhibit reduced hard-X-ray output but higher bolometric luminosities, implying bolometric corrections larger than those typical of the local AGN population, yet consistent with low-redshift highly accreting counterparts. These results support a picture in which many JWST broad-line AGNs are powered by rapidly growing, super-Eddington black holes whose suppressed coronal emission and self-shadowed BLR geometry combine to mimic overmassive black holes at $z \gtrsim 6$.

We present measurements of morphological parameters from fitting 53,885 galaxies detected to a magnitude limit of F356W$< 28.5$ in the CEERS NIRCam imaging with galfit in six broadband filters: F115W, F150W, F200W, F277W, F356W, and F444W. We provide a public catalog of Sérsic index, effective semi-major axis, axis ratio, integrated magnitude, and position angle for these galaxies in each of the filters. Uncertainties in the measured parameters are estimated from simulated galaxies that have similar noise and background properties as the observed galaxies. We compare our measurements with those in the CANDELS/EGS field measured with HST/WFC3 and find that the sizes agree to within 0.09 dex and the Sérsic indices agree to within 0.13 dex. We further present the evolution in the size-mass relation, and find that the evolution to $z\sim9$ is consistent with previous results derived at lower redshift. Finally, we look at the color gradients of galaxies at $1<z<5$ and find that for late-type galaxies ($n<2.5$), there is a strong dependence on mass, but no apparent evolution with redshift, indicating that the stellar populations and dust attenuation in more massive galaxies vary substantially with radius and contribute to significant morphological $k-$corrections. For early type galaxies ($n>2.5$), the color gradients are nearly flat with no dependence on mass, indicating that the stellar populations are more uniform throughout. The structural measurements presented are accurate to $20\%$ or better for most galaxies with F356W $<27.0$ mag and will enable further studies of galaxy morphology to $z\sim10$.

We present the discovery and subsequent 3.2 year monitoring campaign of the repeating fast radio burst FRB 20220529A with CHIME/FRB. We observe a gradual dispersion measure (DM) decline of $-0.881\pm0.001~\mathrm{pc}~\mathrm{cm}^{-3}~\mathrm{year}^{-1}$ ($-1.235\pm0.001~\mathrm{pc}~\mathrm{cm}^{-3}~\mathrm{year}^{-1}$ in the rest frame), implying a $\geq3.5\pm0.2$% decrease of the total electron column in the source environment, and we see scattering timescale variations over weeks to years. We observe a short-lived excursion in which the DM rises by $\sim 1~\mathrm{pc}~\mathrm{cm}^{-3}$, immediately preceding a transient $\sim 2000~\mathrm{rad}~\mathrm{m}^{-2}$ Faraday rotation measure (RM) increase previously reported for this source, before returning to its gradual DM decline. We identify a local line-of-sight magnetic field around FRB 20220529A during this DM/RM excursion of $3.4 \pm 0.2~\mathrm{mG}$, corresponding to one of the most strongly magnetized FRB environments. We measure a decrease in the linear polarization fraction of FRB 20220529A bursts with decreasing frequency that we attribute to depolarization from multi-path propagation in the source environment. We also place a $5\sigma$ upper limit on the spectral luminosity of an associated persistent radio source of $\leq 5\times10^{28}~\mathrm{erg}~\mathrm{s}^{-1}~\mathrm{Hz}^{-1}$ at 1.5 GHz. These observations are consistent with FRB 20220529A originating from a young ($\sim$ years to centuries old) expanding supernova remnant, with short-lived DM and RM variability arising from interactions with the supernova remnant or with a binary companion.

We present the first analysis of the X-ray Imaging and Spectroscopy Mission (XRISM) observation of the supernova remnant (SNR) N103B. We fit the X-ray spectrum taken with the Resolve microcalorimeter, which captured emission lines from the predominantly ejecta elements Si, S, Ar, Ca, Cr, Mn, and Fe. Notably, our fits require a previously unidentified high-temperature, highly-ionized, Fe-dominated plasma component with particularly high Cr and Mn abundances, matching a feature also present in the recent XRISM analysis of the SNR N132D. We find that all ejecta in N103B exhibits significant line broadening arising mostly from thermal Doppler broadening: increasing from $\sigma_{\rm th}\sim1700$ km s$^{-1}$ for intermediate-mass element (IME: Si, S, Ar, and Ca) ejecta to $\sim$2800 km s$^{-1}$ for Fe-rich ejecta. These velocities correspond to reverse shock velocities of $\sim$3500 and $\sim$5900 km s$^{-1}$, respectively, in the ejecta frame of rest. Finally, we find that the IMEs are redshifted with a bulk velocity of $\sim$360 km s$^{-1}$ while the Fe-dominated components are split: one redshifted at $\sim$1560 km s$^{-1}$ and the other blueshifted at $\sim$1020 km s$^{-1}$. Our results provide further support for the double-ring structure of N103B as it expands into the bipolar winds of a non-degenerate companion and highlight the strength of high-resolution spectroscopic observations of SNRs.

Large scale phenomena in spiral galaxies such as shear, supernovae, and magnetic fields all contribute to the formation and subsequent evolution of filamentary structure and star formation within them. In this paper, we analyze the properties and dynamics of filaments in a simulated Milky Way-like galaxy from Zhao et al. 2024. Using filament and superbubble structure analysis codes, we investigate the roles of galactic shear, supernovae and superbubbles, and magnetic fields on the stability and fragmentation of filaments. We find that local shear has little effect on filament stability and the largest structures at outer radii of the disk may be more likely to be dissipated by shear than supernovae. Filaments are largely parallel to the magnetic field, which plays a significant role in filament stability. By measuring the ratio of surface pressure on a filament to that on its central spine, $\chi_f=P_{surf}/P_{central}$, we find that filaments with $\chi_f \le 1$ are dominated by their own self gravity and have a strong tendency to be gravitationally supercritical, whereas those with $\chi_f > 1$ are either transitory or in the act of being formed. Finally, we investigate the role of ISM pressure on filament dynamics and stability as a function of galactic radius, finding considerable changes in filament stability and the accompanying star formation rates in the inner versus outer regions of the disk.

We present the 3-5 $\mu$m transmission spectrum of HD 15337 c (TOI-402.02), a sub-Neptune (2.526 R$_{\oplus}$, 6.792 M$_{\oplus}$, T$_{\rm eq}$$\sim$656 K) around a K1V star observed as part of the JWST COMPASS program. We reduce these observations with two pipelines and find consistent transmission spectra. The resulting median precisions in 30 pixel spectroscopic bins for visit 1 are $\sim$40 ppm and $\sim$70 ppm and for visit 2 are $\sim$30 ppm and $\sim$54 ppm for NRS1 and NRS2, respectively. We attribute the differing precisions to the lack of adequate pre-transit baseline in visit 1 from an early transit arrival caused by previously undetected transit timing variations (TTVs), hinting at a potential exterior companion. Our median JWST timing precision is 10 seconds, revealing TTVs $>$20 minutes when combined with previous TESS and CHEOPS data, highlighting JWST's TTV measurement capabilities. The transmission spectrum of HD 15337 c is featureless and can best be described by a step function with an offset between the NRS1 and NRS2 detectors, likely caused by instrumental systematics. From thermochemical equilibrium retrievals we find that, to $>$3$\sigma$, the data can rule out atmospheres with metallicities $<$600 or $<$310 $\times$ solar, depending on the reduction, for opaque pressures greater than a few millibars. HD 15337 c joins other sub-Neptunes with similar masses, radii, and temperatures in possessing a featureless transmission spectrum indicative of high metallicity and/or high-altitude aerosols and adds support to recent studies showing that aerosol opacity reaches a maximum for planets with equilibrium temperatures of 500-700 K.

We present a JWST/NIRSpec G395H transmission spectrum of TOI-260 b, a $T_\mathrm{eq}\sim 490$ K, $R_\mathrm{p} = 1.76\,R_\oplus$ planet. The transmission spectrum is derived by combining two transit observations, collected as part of the JWST COMPASS program. We achieved the same median transit depth precision of 37 ppm in both visits, and a median precision of 26 ppm when combining the spectroscopic light curves from the two visits. Implementing a 30-pixel-wide ($R\sim 200$) spectroscopic binning scheme, we find that the transmission spectrum is mostly featureless, with a possible feature around 3.17 $\mu$m. We assess the significance of any features in the transmission spectrum with a suite of non-parametric models, which confirm the presence of a potential feature in the NRS1 bandpass and an offset between the NRS1 and NRS2 detectors. To investigate the atmospheric composition of TOI-260 b, we run a series of PLATON retrievals. We do not detect any clear molecular signatures, but the combined data from the two visits are sufficient to constrain the atmospheric metallicity to greater than $200\times$ solar, assuming no opaque deck $\lesssim2.5$ mbar. We also investigate causes of the potential feature near 3.17 $\mu$m; while we find some compatible gaseous species and cannot fully discard an astrophysical origin, we suspect a systematics origin due to the variance in strength and position of the feature. Overall, this look at TOI-260 b adds to the small sample of radius-valley planets, which already seem to show a diversity in their atmospheric compositions. Determining the true nature of these enigmatic planets will require a larger telescope time investment.

The chemical abundances of a stellar population encode information about nucleosynthesis and its astrophysical sites, but this information is confounded by the specific star formation history of the host galaxy. As a result, placing empirical constraints on supernova yields and timing using abundances has been very challenging. We introduce a galactic chemical evolution model DLEIY that uses an observed star formation history and metallicity distribution to reduce these confounding factors. Using a joint statistical model of the dwarf spheroidal galaxies Sculptor and Fornax, simultaneous constraints on population-averaged yields and galactic outflows are achieved with DLEIY, without fixing the absolute scale of nucleosynthetic yields. The Fe yield from core collapse supernovae is consistent with existing theoretical yield models, while the measured Mg yield is a factor of 2-4 higher, corroborating previous suggestions that yield models may under-predict [Mg/Fe]. We also find that the rate of Type Ia supernovae is enhanced by about a factor of 5 relative to field galaxies, and the delay-time distribution goes as $\sim t^{-2}$, a much steeper relationship than that measured from supernova surveys ($\sim t^{-1.1}$). These findings may suggest a metallicity dependence of the Type Ia rate and delay-time distribution.

Non-magnetic Cataclysmic Variables (CVs) show two distinct X-ray components: a hard, optically thin component and a soft, optically thick, blackbody-like component, both produced in the boundary layer between the accretion disk and the White Dwarf (WD). An additional soft component originating from a more extended region has been reported in few CVs. In a short Chandra exposure, we identified a tentative X-ray eclipse in UU Aqr, a non-magnetic CV which shows deep optical eclipses. Using observations with the Nuclear Spectroscopic Telescope Array (NuSTAR) and the XMM-Newton, we detect total eclipses in the orbital intensity profiles of this system in the hard X-ray band (3-10 keV with XMM and 3-25 keV with NuSTAR). However, the soft X-ray band (0.3-2.0 keV) shows no evidence of an eclipse. Detailed eclipse modeling, energy-resolved power spectral analysis and broadband spectral modeling indicate that the hard absorbed X-ray emission originates from a compact region near the WD, such as a boundary layer, while the soft, unabsorbed and un-eclipsed X-ray emission originates in an extended region. Neither scattering of hard X-rays nor colliding winds can account for the observed un-eclipsed soft emission. We instead propose that this component is produced by shocks within vertically extended, radiatively driven accretion-disk winds. We also provide new estimates on the emitting regions, mass and radius of the WD and the donor star using eclipse modeling.

The Starlink Tables Infrastructure Library Tool Set (STILTS) is a powerful suite for astronomical data analysis, particularly useful when dealing with large datasets. However, like other software suites in astronomy its comprehensive syntax creates a significant learning curve to new users. To address this, we present STILTS-NLI, a natural language interface that generates STILTS commands from user prompts, with agentic support for a user-friendly experience. We developed STILTS-NLI by fine-tuning a compact, open-source Large Language Model (LLM) on a synthetically generated dataset. This dataset was curated and validated to ensure both comprehensive coverage of key STILTS functionalities and the syntactic correctness of the resulting commands. Our results demonstrate that this specialised model generates valid commands that match and in some cases outperform larger proprietary models. By leveraging small, open-source models, STILTS-NLI provides an accessible, low-resource solution that lowers the barrier to entry for using STILTS.

Using JWST/MIRI observations, we report the detection of CO$_2$ ice in the dusty torus of the planetary nebula NGC 6302, an environment generally considered hostile to fragile molecular species and ices due to intense UV irradiation. This detection accompanies cold (20-50 K) gas-phase CO$_2$ along the same sightlines. The ice absorption profile exhibits a double-peak profile, a characteristic of pure, crystalline CO$_2$ ice. The CO$_2$ gas-to-ice ratio is more than an order of magnitude higher than in young stellar objects, pointing to distinct ice formation or processing mechanisms in evolved stellar environments. This discovery demonstrates that the dusty torus provides sufficient shielding to harbour ice chemistry, and that ice-mediated surface reactions must be incorporated into chemical models of planetary nebulae.

The evolutionary classification of molecular clumps, crucial for understanding star formation, is commonly based on human-assigned categories derived from infrared (IR) emission and well-established morphological criteria. However, due to ambiguous signatures, distance uncertainties or heavily obscured IR emission, a significant fraction of sources often remains unclassified. This work demonstrates the capability of machine learning (ML) as a complementary, data-driven approach to automate the identification and classification of these clumps using data from the MALT90 survey, complemented by Spitzer IR photometry. We applied unsupervised clustering with HDBSCAN on molecular line intensities, revealing distinct groupings that correspond to evolutionary stages. Using only five molecular lines (HCO$^+$, HNC, N$_2$H$^+$, HCN, C$_2$H), we identified stable clusters of protostars and regions without active star formation, driven primarily by C$_2$H and N$_2$H$^+$ emission. Incorporating H$^{13}$CO$^+$ gave rise to a distinct UV-dominant cluster, tracing more evolved regions. Infrared properties appeared as non-significant features implying that envelopes of clumps with different masses are similar in their global infrared characteristics. We then employed supervised learning to classify clumps with previously uncertain categories and provided classifications for 522 objects, predominantly as regions without active star formation. Our results show that ML techniques can effectively uncover intrinsic evolutionary structures in complex astrochemical data and assign categories to uncertain sources, providing a powerful, data-driven complement to traditional methods.

We present 3D-Herschel, a new 0.3-350$\mu$m photometric catalog that combines deblended Herschel far-infrared (FIR) imaging with the CANDELS/3D-HST legacy fields to probe the dust-obscured universe. Using the 17-parameter fitting code Prospector-$\beta$, a Bayesian inference framework, we model 41,387 galaxies spanning 0.5 $< z <$ 2.5 to measure stellar and dust properties with realistic error bars. Comparing fits with and without FIR constraints, we find that for the 3.2$\%$ of galaxies with $>3 \sigma$ detections in at least two Herschel bands, UV-MIR-only models (0.3-24$\mu$m) recover robust stellar ages, SFRs, and stellar masses (50-70$\%$ within the median 1$\sigma$ error). Consequently, the star-forming sequence shows no systematic offset, with an average deviation of 0.1$\pm$0.07 dex at fixed stellar mass for FIR-detected sources at all redshifts. However, the use of rigid log-average IR templates with fixed dust emission parameters ($\gamma$, $U_{\mathrm{min}}$, $Q_{\mathrm{PAH}}$) in UV-MIR modeling corresponds to an unevolving MIR-to-IR luminosity ratio and cold dust temperatures. By contrast, fits that include Herschel photometry, with added freedom in the FIR, yield dust temperatures that are $\sim$7K warmer at all redshifts, with $\sim$0.2 dex higher IR-to-7.7$\mu$m luminosity ratios at the low-mass end of a Herschel-detected sample (log($M_{\star}$) $\sim$9.6 $M_{\odot}$). These results demonstrate that MIR-to-IR conversions depend on stellar mass, cautioning against $L_{\mathrm{IR}}$-independent templates without FIR data. For galaxies with $<10^{11} \ M_{\odot}$ at $z>1.5$, even with state-of-the-art analysis, Herschel can at best provide upper limits due to source confusion; next-generation FIR telescopes will be essential to fully characterize dust emission in distant galaxies.

We test whether "Little Red Dots" (LRDs) are dust-reddened, high-inclination counterparts of compact, blue broad-line AGNs ("Little Blue Dots", LBDs) powered by super-Eddington accretion. We model the central engine as a geometrically thick, radiation-pressure supported accretion flow whose funnel yields strongly anisotropic, intrinsically blue ionizing continua, coupled to an equatorially concentrated BLR and a dusty screen with modest covering factor. Using inclination-dependent SEDs as input to Cloudy, we show that the extreme broad Halpha equivalent widths (EWs) of JWST LRDs are reproduced with global BLR covering factors of only 15%, consistent with standard Type 1 AGNs. Large Balmer EWs arise because self-shadowing suppresses the high-inclination optical continuum while the BLR is illuminated by an EUV-rich SED. Weak high-ionization lines follow from orientation-dependent suppression of the XUV/soft X-ray continuum toward equatorial directions, without requiring a fully enclosing gaseous "cocoon". With a gray attenuation law of AV = 2.8 along LRD-selected sightlines, the fiducial model matches the V-shaped UV-optical continua and large Balmer decrements; strong Balmer breaks occur only for the most obscured views. A compact equatorial dust component tied to the BLR and normalized by energy conservation intercepts and reradiates only a small fraction of Lbol, producing a modest hot-dust bump and far-IR/sub-mm emission consistent with current limits and implying small dust masses. The model unifies LRD and LBD observables via orientation, predicting correlated trends in Halpha EW, Balmer decrement, Balmer break, high-ionization line strengths, and IR emission.

We analyzed millimeter-wave data toward the quasar B0218+357 observed with the Atacama Large Millimeter/submillimeter Array and obtained absorption spectra of the $J$=2-1 and $J$=3-2 rotational transitions of HCN, HCO$^{+}$, HNC, H$^{13}$CN, and H$^{13}$CO$^{+}$ at the cosmological redshift of $z\!=\!0.68$. For HCN, HCO$^{+}$, and HNC, we identified two distinct absorption components that are common to both transitions, whereas a single component was detected in the isotopologue spectra. In this paper, we accurately evaluate the excitation temperatures and their uncertainties from the absorption strengths of these components, and use them to determine the CMB temperature. Uncertainties in the continuum covering factor were propagated into the excitation temperature via Monte Carlo sampling. We further corrected the observed optical depths for biases due to column-density nonuniformity by assuming a lognormal column-density distribution. Under the assumption that the rotational levels are in radiative equilibrium with the cosmic microwave background (CMB), we derived excitation temperature profiles in the optically thin regime. Because the excitation of HCO$^+$ is biased by an additional velocity component and partial collisional excitation, this species was excluded from the final determination of the CMB temperature. From a weighted mean of the excitation temperatures obtained from HCN and HNC, we determined the CMB temperature at $z\!=\!0.68$ to be ${4.50\pm0.17\,\mathrm{K}}$. This constitutes the first measurement of the CMB temperature at $z\!=\!0.68$ based on a quasar absorption line system and represents the most precise determination at this redshift, highly consistent with the standard Big Bang cosmological model.

We present Cepheid-based distances to two canonical AGN: NGC 4303 (M 61) and NGC 1068. Data were obtained using the Hubble Space Telescope with nonredundant time spacing over 12 visits for each target, and observations were made with the F555W and F814W filters. We found 32,694 point sources in NGC 4303, and 130 of these were determined to be strong Cepheid candidates with periods ranging ~$13-93$ days. In NGC 1068, we found 20,207 point sources, where 51 of these were strong Cepheid candidates with periods ~$14-92$ days. We fit the period$-$luminosity relationship, calibrated based on a geometric distance to the LMC by Riess et al. (2019), to our Cepheid candidates in each galaxy and correct for potential effects of metallicity. Using a distance constraint for the LMC given by Pietrzyński et al. (2019), this yields a distance modulus of $\mu = 31.083 \pm 0.035$ mag for NGC 4303 and $\mu = 30.150 \pm 0.106$ mag for NGC 1068. Thus, we measure distances of $D = 16.47 \pm 0.27$ Mpc to NGC 4303 and $D = 10.72 \pm 0.52$ Mpc to NGC 1068.

The $\gamma$-ray-emitting narrow-line Seyfert-I ($\gamma$-NLSy1) are among the most interesting systems for studying disk-jet coupling. The soft X-ray properties of these systems suggest the presence of a disc component, which peaks in the optical/UV regime, in addition to the active jet. In this work, we investigate the optical emission from $\gamma$-NLSy1 using long-term Zwicky Transient Facility (ZTF) observations and discussed in the context of blazars. We have reported the long-term flux and color variability in the g- and r-bands. The fractional variability ($F_{\rm var}$) goes as high as 72\%, with a mean value of 23\%, while the amplitude of variability ($\psi$) values range from 0.24 to 3.20, which is consistent with the long-term Swift-UVOT variability studies. The color-magnitude diagrams exhibit an RWB or BWB trend similar to that of blazars. The $t_{\rm var}$ suggests an emitting region size of $10^{15-17}$ cm, aligned with emissions coming from the inner accretion disk or base of the jet. The PSD analysis using both DRW and CARMA modeling exhibits a characteristic break timescale of a few days to hundreds of days, which is likely linked to fundamental physical timescales in the system, such as thermal or viscous timescales in the accretion disk or timescales for acceleration and energy dissipation in the jet. The existence of these timescales acts as another signature of the disc-jet connection. These time scales are correlated with black hole mass, and the relation is consistent with previous studies.

This paper investigates the physical and kinematic properties of dust-rich regions in a small sample of group-centered elliptical galaxies, emphasizing their connection with the hot X-ray emitting gas and detailed dust grain characteristics. Comprehensive multi-wavelength data, including H-alpha and CO emission detected by MUSE and ALMA, demonstrate the presence of dust clouds embedded within complex, hot X-ray atmospheres shaped by AGN feedback. X-ray images show bubbles and cavities surrounded by bright rims. We find that dust regions containing molecular gas traced by CO are preferentially located at the rims of these X-ray cavities, suggesting that AGN-driven outflows enhance the condensation of cold, dusty gas at these compressive interfaces. Kinematic measurements indicate that molecular and ionized gas phases are dynamically and spatially linked, supporting the framework of a multiphase medium arising from the top-down condensation rain in the hot plasma and related chaotic cold accretion. Crucially, spatial variations in the total-to-selective extinction ratio Rv show that regions where dust, CO, and H-alpha emission coincide exhibit notably smaller Rv values, implying steeper extinction curves and the predominance of smaller or less evolved dust grains within these mixed-phase environments. This contrasts with larger Rv values found elsewhere in the dust clouds, suggesting grain growth or survival mechanisms within shielded cold gas.

We present a major update to the open-source atmospheric modeling package \texttt{PICASO}, designed for simulating the thermal structure and spectra of hydrogen-rich atmospheres of brown dwarfs and exoplanets. This release, \texttt{PICASO 4.0}, expands upon the existing radiative-convective equilibrium model framework by incorporating several new capabilities. Key additions include the integration of \texttt{Virga} for self-consistent cloud modeling, new flexible treatments for rainout and cold trapping of volatile species, and support for photochemistry. We also introduce a parameterized energy injection scheme to simulate additional external or internal heating processes. These features are motivated by lessons from recent JWST observations that reveal the prevalence of non-equilibrium chemistry and clouds. We benchmark the new functionalities against previously published results in the literature, including the Sonora Diamondback grid, energy injected atmospheres, patchy cloud models, and other photochemical models of WASP-39b. \texttt{PICASO} continues to be actively developed as an open-source package aimed at enabling reproducible, community-driven atmospheric modeling of all substellar objects.

The Transiting Exoplanet Survey Satellite (TESS) mission has facilitated studies of asteroseismology, eclipsing binaries, and transits in many stars. However, the brightest stars saturate TESS, yet they are the most amenable to photon-hungry high-resolution studies and have long observational histories. In this work, we adapted the halo photometry used in $K$2 to extract light curves from the unsaturated halo pixels of the star's point spread function. We used this method to extract light curves for 98 of the brightest stars observed by TESS in Sectors 1-93. These bright stars include 15 red giants, five $\delta$ Scuti variables, eight stochastic low-frequency variables, eight eclipsing binaries, and 46 other variables. We measured $\nu_{\rm max}$ for 13 red giants using pyMON and $\Delta\nu$ for one of them, $\beta$ Gem (Pollux). For five of them, this represents the first time that oscillations were detected. We derived their stellar masses using the measured $\nu_{\rm max}$ and previous interferometric and radiometric angular diameters. We also discovered $\delta$ Scuti and $\gamma$ Doradus variability in $\alpha$ Cep, possible asteroseismic binary signatures in $\epsilon$ Car, and a new eclipsing binary, $\gamma$ And. Furthermore, we identified 18 stars in our sample that will be observed by the future PLAnetary Transits and Oscillations of stars (PLATO) mission, and 69 stars that have Stellar Observations Network Group (SONG) observations, including some simultaneous with TESS. The light curves are publicly available on the Mikulski Archive for Space Telescopes.

The supermassive binary system, $\eta$ Carinae, is experiencing enormous wind-driven mass loss at a rate unparalleled in the rest of the Galaxy. Their wind-wind collision (WWC) continuously produces shock heated, X-ray emitting plasmas. The XRISM X-ray observatory observed the system in 2023 and 2024 when the X-ray emission began to increase toward periastron passage in 2025. This manuscript reports unprecedentedly high-resolution X-ray spectra in the iron K$\alpha$ band between 6.2 and 7.1 keV, obtained with the Resolve X-ray microcalorimeter. The hydrogen-like (Ly$\alpha$) and helium-like (He$\alpha$) lines reveal three velocity components. Two of them are broadened with maximum velocities of 2000-3000 km/s, likely originating from the post-shock companion wind. The other is relatively narrow, with a Gaussian broadening of only ~290 km/s in 1 sigma, which may originate from the post-shock companion wind at the WWC stagnation point or penetrating the primary wind. The iron fluorescent lines exhibit a moderate blueshift and broadening with velocities at 100-200 km/s, consistent with the primary wind's velocity field. The spectra also confirm a Compton shoulder of the He$\alpha$ line complex for the first time. Both fluorescing and scattering spectral profiles indicate that the binary system is seen from the companion side during these observations. The flux ratio of the Compton scattering emission to the fluorescent line suggests substantial hydrogen depletion of the primary wind, expected from CNO-cycled hydrogen nuclear fusion gas.

It is widely believed that stellar-mass black holes (sMBHs) exist within the accretion disks of active galactic nuclei (AGN), forming a distinct population termed ``accretion-modified star" (AMS). Gas from the dense disk accretes onto these AMSs, dissipating substantial gravitational energy through a mini-disk around the sMBHs, which drives powerful outflows that interact with the surrounding disk gas. In this study, we investigate two scenarios for AMS accretion: episodic Bondi explosions with hyper-Eddington accretion (Scenario A) and steady Eddington accretion (Scenario B). These outflows generate turbulence, facilitating outward angular momentum transport in the AGN disk via shock interactions and angular momentum exchange. We explore a broad parameter space-spanning the central supermassive black hole (SMBH) mass ($M_{\rm p}$), dimensionless accretion rate ($\dot{\mathscr{M}}_{\rm p}$), sMBH mass function, and spatial distribution-to calculate the effective viscosity parameter $\alpha_{\rm AMS}$. Our analysis reveals the scaling relations $\alpha_{\rm AMS}\propto\zeta M_{\rm p}^2\dot{\mathscr{M}}_{\rm p}$ for Scenario A and $\alpha_{\rm AMS}\propto\zeta M_{\rm p}^{1.5}\dot{\mathscr{M}}_{\rm p}^{0.1}$ for Scenario B, where $\zeta$ denotes the ratio of total sMBH mass to the SMBH disk mass. For $\zeta={0.01}$ and $M_{\rm p}=10^8 M_\odot$, $\alpha_{\rm AMS}$ ranges from $\sim{3\times10^{-4}}$ to ${0.01}$ (Scenario A) and $\sim{3\times10^{-3}}$ to ${0.04}$ (Scenario B) from the inner to outer disk regions. These results demonstrate that AMS feedback provides an efficient mechanism for angular momentum transport in AGN disks.

Context:Satellite dwarf galaxies provide key constraints on galaxy formation and evolution as their abundance and spatial distribution reflect both host properties and large-scale environment. Aims:This study quantifies the dependence of satellite populations on host stellar mass, morphology and star formation activity across diverse environments and traces their evolution with cosmic time within the LCDM framework. Methods:The Millennium simulation combined with the semi-analytic model is employed to construct consistent samples of host galaxies brighter than Mr < -16 and their satellites (M_* >= 3x10^5 M_sun, Mr < -9) within their virial radius. Satellite abundance and radial profiles are analyzed in cluster, group and void environments and their evolution is traced from z=2 to z=0 across three host stellar mass bins. Results:Satellite abundance correlates strongly with host stellar and bulge mass while host morphology has little additional impact once stellar mass is controlled for. Dense environments suppress satellite populations relative to voids. At z=0 radial profiles reveal strong central concentrations in voids flattened distributions in clusters and intermediate trends in groups. Their redshift evolution shows progressive flattening for low- and intermediate-mass hosts in dense environments stability for massive hosts and increasing central concentration in voids. The cosmic evolution of satellite abundance further highlights distinct pathways: gradual accumulation in voids, mass-dependent trends in groups and strong late-time suppression in clusters. Conclusions:The distribution and abundance of satellite galaxies are governed primarily by environment with host stellar mass and cosmic epoch acting as secondary modulators. Forthcoming wide-field surveys such as LSST, Euclid and the Roman Space Telescope are expected to provide stringent tests of these predictions.

The observed lithum (Li) abundance of Galactic halo stars mainly fall within the range of 2.0--2.4 dex. This nearly constant value, known as the Spite plateau, is approximately a factor of three lower than the value predicted from cosmic microwave background measurements and standard Big Bang Nucleosynthesis (BBN) calculations. This discrepancy -- referred to as the cosmological Li problem -- is considered a potential indication of new physics or astrophysical processes. We employed models incorporating gravitational settling, diffusion, rotation, and magnetic fields to explain the Spite plateau. The rotating models predict that Li abundances in stars with ages of roughly 8--13 Gyr and effective temperatures between 6400 and 5900 K generally fall within 2.0--2.4 dex, forming a well-defined Li plateau, followed by a sharp decline in Li abundance down to about 5200 K. The Li plateau results from the combined effects of variations in convection zone depth, gravitational settling, diffusion, rotation, and magnetic fields. For red giant branch stars with $T_{\mathrm{eff}} \lesssim$ 5200 K, the rotating models predict another Li plateau with an abundance of about 1.0 dex. These results are in good agreement with observations. Moreover, the initial Li abundance of 2.72 dex adopted in the models matches the BBN prediction, implying that the Li problem arises from stellar Li depletion. Furthermore, the rotating models also reproduce the Li and Be distributions of the sample that exhibit the Spite plateau meltdown and Be deviation.

Accurate modeling of geometric distortion is essential for precise astrometric calibration in wide-field imaging surveys. We present a self-calibration method based on Zernike polynomials, applied to imaging data from the Wide Field Survey Telescope (WFST). Our approach constructs a global geometric distortion (GD) model from the position offsets of stars in the WFST r-band relative to Gaia DR3, achieving a median systematic uncertainty of below 10 mas for individual exposures. The correspondence between Zernike polynomials and optical aberrations reveals that the global GD of WFST is dominated by coma, inherent to the optical design, while rapid variations are likely attributed to the atmospheric dispersion corrector. Applying this method to 82 exposures from a single night (20250218), we find that the relative positions of the WFST CCDs remain stable, with standard deviations of less than 0.1 pixel in translation and 1.8 arcsec in rotation. The corrected WFST astrometric system is thereby tied to the Gaia DR3 coordinate frame, with further refinements to be presented in future work.

Stupendously large astrophysical black holes (SLABs) are hypothetical black holes with masses of more than a trillion Suns. Because observable consequences of their existence have only recently been seriously considered, there have been relatively few constraints on their abundance. This work motivates a simple yet powerful constraint on SLABs: their huge shadows are visible against the cosmic microwave background. SLABs could thus appear as negative sources in microwave data. In fact, the shadow of a SLAB with a fixed mass becomes easier to detect with increasing redshifts past $1.6$. The limits are powerful enough to rule out SLABs of mass $\gtrsim 10^{17}\ M_{\odot}$ within the last scattering surface, and imply $\Omega_{BH} \lesssim 10^{-5}$ for masses $10^{15}$--$10^{18}\ M_{\odot}$. I also discuss the effects of accretion and their implications for the limits: SLAB growth, positive accretion luminosity, and obscuring material.

Solitary structures, commonly known as solitons, are a class of nonlinear plasma waves that are abundantly found in near-Earth plasmas and planetary magnetospheres. They are nonlinear, localized plasma waves that maintain their shape and velocity over time and distance. While their occurrence in various space plasma environments has been extensively reported, their observation during geomagnetic storms, large-scale disturbances driven by interactions between the solar wind and Earth's magnetosphere, remains limited. In this study, we present a comparative investigation of magnetosonic soliton signatures during geomagnetic storms associated with Solar Cycles 24 and 25. Using high-resolution in-situ magnetic field measurements from the Cluster II mission, we systematically examine the plasma conditions favorable for soliton generation and their evolution during storm-time dynamics. A comprehensive multi-diagnostic observational framework, incorporating several state-of-the-art analytical techniques, is developed to reliably detect and characterize magnetosonic solitons. The results demonstrate that solitary structures in both storms predominantly occur during the early storm intervals, prior to the main phase, suggesting that they may serve as potential precursor signatures of enhanced geomagnetic activity.

Mid-infrared spectra of planet-forming discs commonly show prominent silicate emission, whose spectral shape is sensitive to the disc temperature distribution as well as its mineralogical composition. We report new James Webb Space Telescope (JWST) observations of the discs around Sz 96 and IP Tau and find that their silicate emission significantly changes in the 20 years since they were observed with the Spitzer Space Telescope (SST). Significant differences between the SST and JWST spectra are found for both sources, with flux variations of 10--15\% in Sz~96 and 30--35\% in IP Tau. Sz 96 dimmed at $\le$ 18~$\mathrm{\mu m}$ and did not change significantly at longer wavelengths, whereas IP Tau became brighter across the entire wavelength range, with a particularly strong enhancement around 10~$\mathrm{\mu m}$ in the JWST data compared to the SST data. We propose that this large degree of variability is explained by structural changes in the inner regions of the discs. Specifically, we also find that crystalline silicates exhibit lower temperatures than amorphous silicates in the JWST data of both sources. This result supports the idea that crystalline grains, formed through high-temperature annealing in the inner disc regions, have been transported outward, leading to their presence in cooler regions of the disc. While similar behavior had been reported in previous SST-based studies, the much higher spectral resolution of JWST enables clearer identification of the crystalline features.

The gravitational wave $\omega$ mode spectrum presents a unique window into the dense interior of neutron stars, probing physics inaccessible to electromagnetic observations. This work investigates the $\omega$ modes of compact stars composed of quarkyonic matter. The quarkyonic model, which describes a cross-over transition between nucleonic and quark matter treated as quasi-particles, is formulated within the Relativistic Mean-Field (RMF) theory using the G3 and IOPB-I parameterizations. This core is surrounded by a mantle of hadronic matter, creating a multicomponent stellar interior. The overall Equation of State (EOS) is governed by two key parameters: the transition density ($n_t$), the QCD confinement scale ($\Lambda_{\rm cs}$), which are varied to construct models consistent with current astrophysical constraints on mass and radius. We compute the complex eigenfrequencies (damped oscillations) of the fundamental and first excited $\omega$ modes using the phase-amplitude method within a full general relativistic framework. Our simulations reveal that the admixed quarkyonic structure produces a unique $\omega$ mode signature, distinctly different from pure hadronic or hybrid stars. The spectrum exhibits a strong, degenerate dependence on the EOS, where the stiffening effect of the quarkyonic matter influences oscillation frequencies and damping times in a characteristic manner. We also demonstrate that $\omega$ mode frequencies for quarkyonic stars follow approximate universal relations, largely independent of the EOS.

We report milliarcsecond-scale VLBI detections of compact radio nuclei in four spiral-hosted, double-lobed radio-loud AGNs (spiral DRAGNs), a rare class that challenges the traditional association of powerful jets with elliptical hosts. Using public VLBI data archives, we identify compact cores in four sources and resolve parsec-scale jets in two of them. The VLBI components show low brightness temperatures ($T_{\rm b} \approx 10^9$ K in the core) and jet-to-counterjet ratios consistent with only mildly relativistic intrinsic speeds ($\beta \lesssim 0.6$ for inclinations $\theta \lesssim 80^\circ$), indicating weakly powered pc-scale outflows. The low radio-Eddington ratios $\log(L_{\rm R,1.4\,GHz}/L_{\rm Edd}) \approx -5$ to $-8$ support this interpretation. Three objects lie on the fundamental plane of black hole activity, implying that global accretion-jet coupling in spiral DRAGNs is similar to that in other AGNs. Comparison with recent GRMHD simulations of thin-disk jets suggests that the VLBI-scale cores in spiral DRAGNs may trace an early or intermittently magnetized phase of jet launching. The coexistence of weak pc-scale jets and large kpc-scale lobes implies recurrent or long-duty-cycle jet activity in these late-type hosts.

This study introduces an automated approach for identifying the tip of the red giant branch (TRGB) in globular clusters, combining astronomical data with algorithmic methods. Using a dataset of 160 globular clusters and Python scripts, we matched stellar sources with Gaia data. Our script generates color-magnitude diagrams (CMDs), and uses the local outlier factor (LOF) algorithm to remove outliers. Applying a second-degree polynomial to fit red giant branch (RGB), we identify the TRGB as the star closest to the fitted curve's endpoint. By this method, we expanded TRGB samples in global clusters to 91 with newer observational data. Our results show a decreasing trend in I-band luminosity for metallicities greater than $-$1, consistent with previous studies. The results show a robust trend fitting and the $\rm M_{I}$ of TRGB is about $-$4.02 with extremely low metallicity. Our approach enhances TRGB identification efficiency while providing valuable insights for developing automatic tools in astronomical data analysis.

Finding intermediate-mass black holes (IMBHs) and measuring their masses and spins are key to understanding massive black hole formation. White dwarf (WD)-IMBH binaries provide a unique probe because they emit both electromagnetic radiation and gravitational waves (GWs), thereby conveying richer information. However, such multi-messenger sources often enter the regime of strong gravity, where existing models fail to capture their relativistic dynamics. Here, we develop a fully relativistic model for the tidal response of a WD close to an IMBH and use it to study the secular orbital evolution as well as the GW signal. We find that for IMBHs more massive than 10^5 solar masses, tidal interaction becomes relativistic and sensitive to IMBH spin. The interaction generally dissipates binary orbital energy and angular momentum, but due to relativistic frame rotation, which reduces phase coherence across pericenter passages, the orbit-averaged tidal dissipation rate can be suppressed by up to about 50% relative to Newtonian predictions. Including tidal dissipation leads to more rapid damping of the orbital eccentricity, to the extent that the pericenter distance may even increase over time, potentially explaining quasi-periodic eruptions and secular orbital period growth. Such tidal effects accumulate into measurable phase and amplitude deviations in the GW signal. For typical space-based observations, the GW waveform mismatch can reach values of order 0.1 within 6 months. Our results indicate that relativistic tidal dissipation is both dynamically important and observationally essential for reliably predicting the multi-messenger signals of WD-IMBH systems.

Planet formation theories suggest the presence of free-floating planets (FFPs) that are ejected from their formation sites. While these planets emit very little light, they can be identified through gravitational microlensing. Here, we report the discovery of a FFP candidate in the microlensing event KMT-2024-BLG-3237. The observed light curve exhibits strong finite-source effects characterized by a small amplitude $(\lesssim 0.9\,{\rm mag})$ and a short timescale $(\lesssim 3\,{\rm days})$. The analysis yields an Einstein timescale of $t_{\rm E} = 0.54\pm0.02\,{\rm days}$ and an angular Einstein radius of $\theta_{\rm E} = 6.30\pm0.48\,\mu{\rm as}$. The measurements make it possible to estimate the lens mass as $M \simeq 102\,M_{\oplus}\,(\pi_{\rm rel}/16\,\mu{\rm as})^{-1}$, where $\pi_{\rm rel}$ is the relative lens-source parallax. Depending on the unknown $\pi_{\rm rel}$, the lens could be a Neptune-mass planet $(\pi_{\rm rel} \simeq 0.1\,{\rm mas})$ or a Saturn-mass planet $(\pi_{\rm rel} \simeq 16\,\mu{\rm as})$. A Bayesian analysis yields the lens mass $M = {67.3}_{-42.5}^{+103.2}\,M_{\oplus}$ and the lens distance $D_{\rm L} = {7.34}_{-2.11}^{+0.96}\,{\rm kpc}$. This lens is the eleventh isolated microlens with a measurement of $\theta_{\rm E} < 10\,\mu{\rm as}$. We find that additional searches for possible signatures of a lens host do not show significant evidence for the host.

To address the challenge of estimating redshifts when only single-band images are available, this study introduces a deep learning model named ViT-MDNz. Leveraging robust statistical priors learned from large-scale data concerning the correlation between redshift and morphology, the model can directly estimate redshifts and their associated uncertainties from single-band galaxy images. It integrates a Vision Transformer (ViT) to extract deep morphological features and a Mixture Density Network (MDN) to predict the full redshift probability density function. Trained and evaluated on approximately 300,000 single-band images from the DESI Legacy Imaging Surveys (DESI-LS), the model achieves a normalized median absolute deviation $\sigma_{\rm NMAD} = 0.034$ and an outlier fraction $f_{\rm out} = 2.6\%$ in the $r$-band for redshifts up to $z \lesssim 1$. Evaluations using probability integral transform (PIT) and continuous ranked probability score (CRPS) confirm that the predicted probability density functions are well calibrated and closely match the true distribution. These results demonstrate that competitive redshift estimates can be obtained using morphological features alone, and that incorporating color information further enhances the accuracy and robustness of the estimation. Therefore, ViT-MDNz provides a practical approach for redshift estimation of galaxy samples with limited photometric band coverage, contributing to improved completeness and usability of redshift catalogs for future large-scale surveys such as DESI and LSST.

The Variables and Slow Transients (VAST) Survey on the Australian SKA Pathfinder (ASKAP) is designed to systematically explore the dynamic radio sky, detecting sources that vary on timescales from minutes to several years. In this paper, we present Data Release 1 of the VAST Extragalactic Survey, which targets slowly evolving synchrotron transients in the southern sky. The observations were carried out between June 2023 and May 2025, comprising 2945 images of 276 fields spanning $\sim 12300\ \mathrm{deg}^2$, observed at 888 MHz with a typical rms sensitivity of 0.24 mJy $\rm{beam}^{-1}$ and 12-20 arcsec resolution. Each field was revisited approximately every two months, yielding 10 or 11 observations per field. The VAST pipeline extracts the light curves for all the observed sources, and additional filters are implemented to improve the reliability of the resulting light curve database. The light curve database contains 0.5 million sources and 6.4 million individual measurements, publicly available through the CSIRO data access portal. An untargeted variability search yields 117 astrophysical variables, including 27 pulsars, 40 radio stars (10 newly detected at radio wavelengths), 44 active galactic nuclei, two optically identified supernovae, one supernova candidate, one brown dwarf, and two sources without multi-wavelength counterparts that are yet to be identified. This data release provides the first large-scale, high-cadence, uniform view of long-term radio variability in the extragalactic sky and lays the groundwork for future population studies of radio transients with ASKAP.

Fast radio bursts (FRBs) are brief flashes of emission detectable to cosmological distances. Cosmology applications rely on an understanding of how the detected sample relates to the underlying population. To this end we examine the dispersion measure `tolerance' parameter employed by the FRB search tool \textsc{heimdall} and provide the relation between this and minimum search depth. Several FRB samples can be `retro-fitted' using this to more properly account for survey completeness.

We investigate the role of contact interactions in the dynamics of fuzzy dark matter (FDM) modeled through the Schrödinger-Poisson equation in one spatial dimension. While the $\Lambda$CDM paradigm successfully explains structure formation on large scales, its small-scale predictions remain in tension with observations. FDM offers an alternative framework, where local self-interactions can further influence the formation and evolution of structures. We explore both attractive and repulsive contact interactions in static and expanding backgrounds. Using numerical simulations, we examine their impact on three key scenarios: the properties of the lowest-energy stationary solution, the relaxation of localized initial states, and the gravitational collapse of nonlocalized states. Our results show that contact interactions modify the density profile of the stationary solution and affect the onset of characteristic stages of gravitational collapse, particularly the shell-crossing event. In the (1+1) model, we confirm that relaxation does not converge to the lowest-energy stationary solution, even when local self-interactions are included. Taken together, local self-interactions play a relevant role in shaping the nonlinear dynamics of FDM and motivate further studies in higher-dimensional and cosmologically realistic settings.

Rapid Blue Excursions (RBEs) are transient blue-shifted chromospheric absorption features widely interpreted as the on-disk counterparts of Type II solar spicules. We investigate their dynamic properties using high-cadence spectral observations combined with automated detection and spatio-temporal tracking algorithms. RBEs were identified through blue-wing Doppler asymmetry criteria and tracked using spatial connectivity and centroid continuity methods to determine lifetimes and kinematic evolution. The statistical analysis shows that RBEs are short-lived events with lifetimes predominantly between 20 to 60 s and a mean duration of approximately 75 s. The lifetime distribution follows an exponential decay profile, indicative of impulsive driving. Line-of-sight velocities range from 20 to 140 km s-1, with a mean near 26 km s-1. Projected lengths span 1.2-5.5 Mm with sub-arcsecond widths, and recurrence analysis reveals repeated activity at localized magnetic footpoints. Mass flux estimates suggest that RBEs transport significant plasma upward, contributing to chromospheric mass supply toward the corona. These findings reinforce the role of RBEs as dynamic conduits of mass transfer and key elements in chromosphere-corona coupling.

We present a supervised, probabilistic taxonomic classification of asteroid reflectance spectra from Gaia Data Release 3 (DR3). Using high-quality Gaia DR3 spectra and a reference set of spectra from the literature consisting exclusively of asteroids with robust spectroscopic taxonomic types, we construct a principal-component (PC) representation of the Gaia reflectances. For each major spectral complex (C, S, X) and several end-member classes (B, D, A, L, K, V), we model the distribution of reference objects in PC space using multivariate kernel density estimation (KDE). This yields likelihoods for each spectral class and provides a quantitative measure of classification confidence. Validation against a sample of objects with known spectral classes demonstrates good performance for classes with distinctive reflectance signatures, including the S-complex, D, V, and A types. Spectrally continuous classes (B-C-complex, K-L-S-complex, and X-complex) show the expected degrees of mixing given the limited wavelength range of Gaia's spectrophotometry. We further explore the compositional structure of six major asteroid collisional families using our Gaia-derived spectral classes, finding excellent agreement with ground-based spectroscopy and revealing enhanced detections of olivine-rich A type material in the Flora and Eunomia families, as well as new insights into the spectral diversity of the Tirela family. The resulting catalogue constitutes a fully probabilistic taxonomic classification for the full Gaia DR3 asteroid sample. It offers a resource for studying the compositional structure of the main belt, identifying family interlopers, and linking asteroid populations to meteorite groups, and establishes a methodological framework for future Gaia releases, in particular for the validation of the Gaia DR4, expected by the end of 2026.

Relativistic jets from black holes can extract energy not only from accretion but also directly from the black hole's spin, as described by the Blandford-Znajek mechanism. A longstanding question is whether magnetic flux can accumulate near the event horizon to such an extent that it halts accretion entirely, enabling energy extraction purely from spin. Previous studies have shown that accretion persists through instabilities and that jet power only modestly exceeds the accretion energy budget, yet some observational results suggest much higher efficiencies. Here we present state-of-the-art general relativistic magnetohydrodynamic (GRMHD) simulations that sustain a quasi-steady magnetically arrested disk state for approximately 10,000 dynamical times, during which accretion is globally suppressed across the full azimuthal extent. In this regime, jet power exceeds the accretion energy input by more than two orders of magnitude, demonstrating a previously unachieved level of efficiency. These results challenge conventional assumptions about the limits of black hole energy extraction and suggest a new framework for interpreting powerful jet systems. Our findings raise important questions about the long-term stability of such states and the fundamental limits of the Blandford-Znajek process.

High-resolution cross-correlation spectroscopy (HRCCS) has emerged as a powerful technique for detecting and characterizing exoplanet atmospheres from the ground. While it has been highly successful for ultra-hot Jupiters and hot Jupiters, next-generation facilities such as ELT/ANDES will extend its reach to smaller and longer-period planets, including young sub-Neptunes and their progenitors. We investigate whether HRCCS with ELT/ANDES can robustly recover orbital parameters and atmospheric signals of the long-period sub-Neptunes V1298Taub and TOI-451c. For such systems, the slow Doppler drift of the planetary signal over a single night reduces its separation from stationary telluric contamination, increasing the risk of signal removal while detrending. We therefore quantify the impact of including out-of-transit exposures on signal recovery and parameter estimation. We simulate transmission observations in the YJH bands using the Ratri pipeline and analyze them with the HRCCS framework Upamana. For V1298Taub, we inject atmospheric signals consistent with HST, Spitzer, and JWST constraints. For TOI-451c, we explore models spanning sub-solar to super-solar C/O ratios to assess compositional sensitivity. We find that incorporating out-of-transit exposures significantly enhances detectability, provided that the detrending effects are consistently propagated to the template models prior to cross-correlation. Without this reprocessing step, recovered orbital parameters can deviate substantially from injected values or yield reduced detection significance. For V1298Tau b, >5$\sigma$ detections of H2O, H2S, and CO are achievable within $\lesssim$10 hours (~2 nights). For TOI-451c, distinguishing sub-solar from super-solar C/O ratios requires $\geq$18 hours. HRCCS with ELT/ANDES will therefore be a key tool for probing the atmospheric diversity of young, long-period sub-Neptunes in the ELT era.

It is important to detect and study circumstellar disks around late-M and brown dwarfs of nearby young associations to understand how these very low-mass objects form and how rocky planets form around them. The detection of new very low-mass members of nearby young associations will also significantly improve our current understanding of young associations. We searched for new young very low-mass members with circumstellar disks in a sample of 3928 candidates. We constructed spectral energy distributions of all candidates using observational photometric data from DENIS, 2MASS, and WISE and trigonometric parallaxes from Gaia to detect infrared excess emission that indicates the presence of circumstellar disks. We then followed up spectroscopic observations of candidates to search for lithium to confirm their youth. The H_alpha emission line was used to detect accretion. We detected 23 among the 3928 candidates with circumstellar disks: Ten objects are new, and 13 were previously reported in the literature. Our mass estimates also indicate that 21 are brown dwarf candidates and 2 are very low-mass stars. DENIS J0534552-104808 has a Gaia distance of 238 pc and might be the first brown dwarf candidate member of a foreground population in front of the Orion D cloud. This foreground population is probably associated with the supergiant kappa Ori. Based on our spectroscopic observations, we detected lithium in 11 candidates. We also identified seven accretors and one potential accretor. The intense long-lived accretion detected in DENIS-P J0500245-333042, a 20 Myr old brown dwarf candidate may be additional evidence to favor the formation of rocky planets around very low-mass objects.

We develop a modified interacting dark energy (IDE) model to study the redshift evolution of the Hubble constant ($H_0$), in light of the Hubble tension. In this framework, the energy exchange between dark energy and dark matter induces a redshift dependence of $H_0$. We evaluate the model against a comprehensive suite of observations, including baryon acoustic oscillations (BAO) from DESI DR2 and SDSS, cosmic chronometers, type Ia supernovae from the Pantheon sample, and Planck CMB distance priors. Analysis of late-Universe data yields $\alpha = 0.0107^{+0.0032}_{-0.011}$, with the best-fit value on the order of $10^{-2}$, revealing a decreasing trend of $H_0$ with redshift. This supports a power-law evolution beyond $\Lambda$CDM. Incorporating CMB data further tightens the constraint to the order of $10^{-5}$, which we attribute to the suppression of dark-sector interactions at high redshifts, a consequence of the strong baryon--photon coupling. These results indicate that the IDE framework provides a theoretically consistent and observationally viable mechanism for describing the redshift evolution of $H_0$, offering a promising avenue toward alleviating the Hubble tension.

Young star-forming clumps (SFCs) emit strongly in the ultraviolet (UV), making UV imaging ideal for detecting them. The Ultraviolet Imaging Telescope (UVIT) onboard AstroSat, with 1.5arcsec resolution, has enabled the characterization of recently formed (up to 300 Myr) SFCs on tens of parsec scales in nearby galaxies. The spatial distribution of SFCs with different ages can provide insights into the hierarchy of star formation. This study presents a semi-novel approach to characterize SFCs in two nearby spiral galaxies, NGC 5457 and NGC 1313, by combining UVIT FUV data with g-band data from the Dark Energy Camera Legacy Survey (DECaLS). We tested and optimized our method on NGC 5457 and showed that after proper background subtraction, the FUV-g color of SFCs can serve as an equally reliable age indicator as the widely-used FUV-NUV color. Next, we parametrized the star formation hierarchy in NGC 5457 using the two-point correlation function (TPCF) and found good agreement between the hierarchy parameters derived using FUV-NUV and FUV-g based ages. Using our FUV-g based SFC ages, we also constrained the global hierarchy parameter of NGC 1313 for the first time. The development of our FUV-g based method is motivated by the fact that the NUV channel of the UVIT is not operational, and there is a wealth of archival UVIT FUV-only observations of nearby galaxies. This work demonstrates the potential of our method in constraining the SFC ages and investigating hierarchical star formation in nearby galaxies using FUV and optical observations.

The relative roles of secular disc processes and galaxy interactions in driving the growth of supermassive black hole (SMBH) remain unclear. We present a time-resolved, per galaxy analysis of SMBH mass assembly that explicitly tracks bar formation, merger events, and the environment along the main progenitor branches using the high resolution IllustrisTNG50 cosmological simulation. We analyze barred and unbarred disc galaxies in isolated and non-isolated environments using physically motivated boundary definitions. We found that SMBH fueling pathways are regulated by the environment through the timing of bar formation relative to mergers. In isolated barred galaxies, stellar bars form early in dynamically cold discs and establish sustained, coherent accretion phases that regulate late-time SMBH growth. In contrast, in non-isolated galaxies, SMBH growth is dominated by early merger-driven accretion episodes, whereas bars form later and contribute weakly to the primary growth phase. Unbarred control samples show that mergers can trigger rapid SMBH growth without bars, but such growth remains episodic, whereas isolated discs without bars lack sustained accretion. These results demonstrate an environmental bifurcation in SMBH fueling: mergers act as efficient triggers of early growth in dynamically active systems, while bars regulate prolonged accretion only when they form in quiescent discs. This study provides a unified time-domain framework linking galaxy environment, disc dynamics, and SMBH growth by resolving the temporal ordering of bars, mergers, and accretion.

Kilonovae represent key sites of r-process nucleosynthesis, making opacity estimation and spectral analysis crucial for constraining their composition. Since light r-process elements shape the early ($\sim$0.5-1.5$\mathrm{d}$) ejecta opacity, a detailed study of the selenium element with a focus on atomic data calculation, expansion opacity estimation and spectral analysis is presented. Se atomic data are calculated from Se I to Se X using the GRASP2018 code. A systematic analysis and evaluation of their precision is performed through detailed comparison with the NIST ASD, and other works available in the literature. These atomic data are then used to estimate expansion opacity at different temperatures (e.g., T=5000 K, 10000 K, 20000 K, 100000 K) and densities (e.g., $\rho = 10^{-13}\,\mathrm{g\,cm^{-3}},\,3\times10^{-12}\,\mathrm{g\,cm^{-3}}$). Spectral analysis has been performed with radiative transfer code POSSIS with a pre-computed opacity grid calculated with new densities and temperatures, ranging from -19.5 to -4.5 $\mathrm{g\,cm^{-3}}$ in log-scale and from 1 000 to 51 000 K, respectively. Two scenarios are considered: one in which the opacity contribution comes from 100\% Se ejecta, and another in which Se contributes only partially to the total opacity ($\sim$ 10\% of the total mass). Se atomic calculations show a good agreement with NIST ASD, with accurate energy levels and transitions determined alongside atomic data for higher ionisation stages not fully covered by NIST. The expansion opacities calculated with these new Se data exhibit differences in comparison to existing literature works. Se spectral features can only be observed in the KN scenario consisting of 100\% Se. When Se accounts for about 10\% of the total KN mass, these features become undetectable. All Se results are now available in the new open-source MARTINI platform dedicated to element nucleosynthesis.

Interactions within galaxy groups are fundamental drivers of galactic evolution, and establishing a direct observational link between the dynamical processes of satellite galaxies and the rejuvenation of massive host galaxies remains challenging. We present a multi-wavelength work of J1611+4026, a unique triple system characterised by a massive early-type host galaxy, Component C and two gas-rich companions, Components A and B, which are currently undergoing a major merger in its near environment. Utilising deep optical imaging from DESI-LS and spectroscopic data from DESI and P200, we employ 2D morphological decomposition using \textsc{GALIGHT} alongside joint spectrophotometric synthesis modelling with \textsc{BAGPIPES} and \textsc{CIGALE} to deconstruct the structural properties and star formation histories of the member galaxies. Crucially, we identify an asymmetric tidal tail extending $\sim$15.15 kpc from Component A, confirming the ongoing interaction between the companions. Although Component C appears quiescent in both morphology and spectroscopy, we reveal a subtle robust signal of ``minor rejuvenation'', characterised by significant internal dust extinction of $E(B-V) \sim 0.53$ and a UV excess. The reconstructed star formation history indicates a recent ($\sim$100 Myr) starburst that contributes a negligible fraction to the total stellar mass ($f_{\rm burst} < 0.1$ per cent). We propose that this activity is fueled by the accretion of metal-enriched gas stripped from the interacting companions. These results strongly suggest group pre-processing, where interactions between satellite galaxies drive low-level star formation in the massive host through gas transfer, providing a quantitative benchmark for interaction-driven evolution in dense environments.

Long gamma-ray bursts (GRBs) frequently exhibit complex prompt emission structures with multiple temporally distinct episodes, such as a main emission (ME) phase followed by a weak extended emission (EE) tail. Whether these subcomponents from a common physical origin with similar classification properties, or instead represent fundamentally different emission mechanisms within a single event, remains an open question. Here, we present a systematic, pulse-resolved analysis of 22 \emph{Swift}/BAT long-duration GRBs, each exhibiting a well-separated, bright ME ($G_1$) followed by a fainter EE ($G_2$) after a background-consistent quiescent gap. For each component, we independently measure standard classification diagnostics, including duration ($T_{90}$), spectral hardness ratio (HR), minimum variability timescale (MVT), and spectral lag. We then compare these properties between the ME and EE within individual bursts. We find that the EE is systematically softer (lower HR in 19 of 22 events), smoother (longer MVT in 17 of 22 events), and more diverse in spectral lag than the ME. However, both components still occupy the long-GRB track in the traditional duration-hardness and duration-MVT planes, indicating a common Type~II (collapsar) origin. These results suggest that the EE in long GRBs represents a physically distinct regime of the central engine, characterized by a lower luminosity, longer emission timescales, and evolved spectral properties, rather than a simple continuation of the main burst. This picture is consistent with late-time fallback accretion onto a black hole or proto-magnetar spin-down.

Nulling is a phenomenon where the emission from a pulsar becomes undetectable (or significantly weaker) for a relatively short period of time, followed by a return to a normal emission state. The timescale of nulling ranges from a few pulse periods to many hours or even days. The fraction of time a nulling pulsar spends in a null state varies across the population of canonical pulsars, from 0 to 95 per cent. The long-term behaviour of a pulsar's nulling fraction, however, is currently unknown, as published values have typically been obtained through single observations. Here, we present the first long-term analysis of nulling behaviour in eight pulsars observed in the Parkes Multibeam Pulsar Survey over the course of eight to ten years. We also apply a new Bayesian method for pulse-energy analysis, yielding posterior estimates of the nulling fraction per observation. In several cases, the nulling affects only specific components of the pulse profile, rather than the entirety of the emission. Our analysis reveals that, while most pulsars show no significant trend in their nulling fraction over time, a subset exhibit some evidence for non-zero gradients in nulling fraction. In particular, PSRs J1048$-$3832, J1745$-$3040, and J1825$-$0935 show statistically significant trends over the span of the data. Studying the behaviour of nulling over years and decades is valuable as it can provide insights into the physical emission processes within pulsars. Studying how nulling evolves also provides valuable insights into pulsar evolution and the characterisation of the broader pulsar population.

One of the primary objectives of modern astronomy is the atmospheric characterization of Earth-like exoplanets at visible and infrared wavelengths. Achieving this goal requires extremely sensitive detectors capable of measuring faint signal of the exoplanet at the single-photon level while maintaining near-zero dark count rates. In the infrared, however, conventional semiconducting detector technologies struggle to meet these stringent requirements. In this work we demonstrate single-photon counting with superconducting Microwave Kinetic Inductance Detectors at the wavelengths 3.8, 8.5, 18.5, and 25 $\mu$m and measure resolving powers ($E/\delta E$) of 9.9, 5.9, 3.2, and 3.3, respectively, with corresponding dark count rates of 4, 8, 34, and 48 mHz. Our membrane-based devices reach phonon-loss limited performance at 3.8 $\mu$m, more than doubling the performance attainable with comparable solid-substrate devices. These results showcase the detector technology in the mid-infrared and the intricate measurement setup required for these sensitive detectors. We discuss how the detector design and measurement setup can be further optimized to increase the detector performance in the mid-infrared.

With the discovery of a few thousand exoplanets, questions have been raised regarding star-planet interactions and whether the presence of a companion may affect stellar properties. GJ 504 is an evolved (2 Gyr) Sun-like star with a short rotation period (3.4 d) and an intense magnetic activity, which is in stark contrast with what would be expected at such an evolutionary stage. One possible explanation is that a close-in, Jupiter-mass planet was pushed starwards by the action of stellar tides, inducing a stellar spin-up and ultimately a rejuvenation of the stellar magnetic dynamo. By characterising the large-scale magnetic field and magnetised wind of GJ 504, we aim to provide additional observational constraints to test such scenario. We analysed spectropolarimetric observations of GJ 504 collected with ESPaDOnS. Using Zeeman-Doppler imaging, we found a large-scale, dipolar, non-axisymmetric magnetic field with an average strength of 5.3 G, similar to that of evolved early-G type stars. We fed the magnetic field information into our 3D MHD simulation of the stellar wind and space environment of GJ 504, from which we constrained the wind-driven angular momentum loss ($\rm \dot{J}$). We then compared $\rm \dot{J}$ to rotational evolutionary tracks of GJ 504 for two scenarios: evolution with and without the engulfment of a close-in, Jupiter-mass companion. Between the two scenarios, only the planet engulfment can explain the observational constraints obtained previously in the literature, such as the stellar rotation and X-ray luminosity, and the $\rm \dot{J}$ we derived and rescaled to account for underestimated magnetic field strength. Although there are many other stars with similar masses and rotation periods whose rotation evolution does not require planet engulfment, we also identified HD 75332 as a candidate for planet engulfment, suggesting that GJ 504 may not be an isolated case.

We present a Monte Carlo study of galactic cosmic-ray (GCR) energy deposition and its implications for stratospheric chemistry, performed with the Geant4 toolkit. Primary nuclei (protons, $\alpha$, CNO, and Si) were propagated through an atmosphere modeled from 0 to 120~g~cm$^{-2}$, considering both Polar ($R_{\mathrm{c}}=0.1$~GV) and Equatorial ($R_{\mathrm{c}}=15$~GV) geomagnetic cutoff conditions. The simulations resolve the variation of energy deposition with altitude for primary and secondary particles, revealing that $\sim$~96\% of the stratospheric energy budget arises from cascade secondaries within the 15--35~km domain. By converting layer-resolved energy deposition into ion pair production rates, we quantify the resulting formation of odd nitrogen (NO$_{\rm x}$) and odd hydrogen (HO$_{\rm x}$) radicals, which catalyze the destruction of ozone. The modeled production rates peak between 18 and 22~km altitude, leading to an estimated fractional ozone decrease of order $10^{-3}$--$10^{-2}$ under average GCR fluxes, consistent with observed background modulation over the solar cycle. These results establish a physically consistent link between cosmic-ray induced energy deposition and ozone chemistry, providing a benchmark framework for coupling high-energy particle transport to atmospheric photochemical models.

Voids are parts of the cosmic web least affected by non-linearities and baryonic feedback. We thus calculate the sensitivity of voids to the nature of dark matter (DM), using ultra-light axions as a concrete model and the ongoing Dark Energy Spectroscopic Instrument (DESI) and \textit{Euclid} galaxy surveys as observational settings. We simulate axion effects on voids using mass-peak patch simulations and find that: (i) axions suppress the formation of lower-mass halos leading to the merging of smaller (radius $< 25\,\mathrm{Mpc}/h$) voids into fewer larger (radius $> 25\,\mathrm{Mpc}/h$) voids; and (ii) voids in the presence of axions are emptier of halos, thereby suppressing the void-halo correlation function. These effects strengthen as axion particle mass $m_\mathrm{a}$ decreases. We forecast improvements in axion constraints from the void size function (VSF; the void number density as function of their radius). A \textit{Euclid}-like survey (effective volume of $73\,\mathrm{Gpc}^3$ with a prior on the other $\Lambda$CDM cosmological parameters from the Simons Observatory cosmic microwave background experiment) can limit the axion energy density (for $m_\mathrm{a} = 10^{-25}\,\mathrm{eV}$) to $< 4.6\%$ of the DM (at $95\%$ credibility), about two times stronger than current limits. Conversely, we show that a Universe with a dark sector consisting of axions at the $10\%$ level, as motivated by the string axiverse, can be recovered with $\sim 2 \sigma$ preference. A DESI-like survey achieves comparable results. Axion and $\Lambda$CDM parameters have different degeneracies given VSF and galaxy power spectrum data, indicating future combined analyses will be most powerful in disentangling the DM nature. We anticipate our results will extend to other (e.g., warm or interacting) DM models.

We investigate {the arrival time and the Faraday rotation} of extragalactic electromagnetic signals from fast radio bursts (FRBs) propagating through chiral cosmic media within the framework of Maxwell-Carroll-Field-Jackiw {(MCFJ)} electrodynamics. By treating the interstellar medium as a cold, ionized chiral plasma, {we derive} the time delay between two traveling signals, expressing it in terms of modified dispersion measures (DMs) {containing chiral contributions}. {The Faraday rotation angle is then} written in terms of modified rotation measures (RMs). By combining the DMs and redshift data from a set of FRBs, {we obtain} constraints on the chiral parameter magnitude at the order of $10^{-26}$--$10^{-24}$ GeV. {Using the Faraday} rotation formulae and RM measurements, {upper bounds as stringent as $10^{-43}$ GeV on the MCFJ parameters are also obtained.}

Warm debris disks around main-sequence stars trace late-stage terrestrial planet formation. Motivated by the need for systematic searches of such systems, we identify debris disk candidates around FGK stars within 150 pc by combining a spectroscopically selected sample from LAMOST DR12 with Gaia astrometry and multi-band infrared photometry. Infrared excesses are identified through SED fitting and validated using conservative, source-by-source checks. This approach yields a final sample of 12 debris disk candidates including ten new detections. Stellar age research indicate that most of the host stars are several billion years old. NEOWISE monitoring reveals no significant W1/W2 variability, consistent with a circumstellar origin of the infrared excess. while a search for co-moving companions using Gaia DR3 reveals possible companions for only two candidates at very large projected separations ($\gtrsim 10^4$~au). Three candidates exhibit excess emission in both the W3 and W4 bands, allowing estimates of characteristic dust properties. This work establishes a small yet reliable sample of debris disk candidates anchored in homogeneous LAMOST spectroscopy, providing a foundation for future studies of debris disk evolution and stellar activity.

The accretion process in young stellar objects (YSOs) is fundamental to the formation of stellar systems. This process governs the star's mass assembly, the transfer of angular momentum, and the shaping of the protoplanetary disc, thereby influencing planet formation. For classical T Tauri stars (cTTSs), which are low-mass YSOs, accretion is a well-understood process. Their strong, dipolar magnetic field truncates the disc at a few stellar radii. Material is then channelled along these magnetic field lines, creating accretion funnel flows that fall onto the star's surface. However, this paradigm, known as magnetospheric accretion, is limited to isolated stars. The accretion process in multiple systems has not yet been fully understood. This work is part of a series of studies designed to build a framework to understand the accretion process in multiple star systems. The specific goal here is to determine how the magnetospheric accretion model can be used to describe DF Tau, a binary system where only the primary star is accreting material. To investigate how accretion occurs in a system where a single star is orbited by a non-accreting stellar companion, we used a time series of high-resolution spectropolarimetric observations from the ESPaDOnS instrument. This allowed us to study the accretion-related emission line variability, the veiling, and the magnetic field topology of the primary star in the system. Our research concludes that the primary star of the DF Tau system undergoes typical magnetospheric accretion. This process is driven by a strong dipolar magnetic field, which funnels accreting material onto the stellar surface, creating an accretion shock. We also identified a significant difference in the magnetic topology of the two stars querying the influence of accretion of the evolution of the magnetic field, or capture of the secondary star.

Advancing the technological development of small inner working angle (IWA) coronagraphs is essential to enabling high-contrast imaging of temperate exoplanets with future extremely large telescopes. The PIAACMC has been shown to closely approach the theoretical limit for coronagraphic throughput but its performance has not been fully characterised on-sky. This study serves as the first on-sky characterisation of contrast and IWA performance of the PIAACMC and its first technological demonstration at sub-micron wavelengths. We designed and manufactured phase-shifting focal plane masks optimised for two cases, a narrowband 875 filter (875nm, 3% band) and a broadband z' filter (908nm, 14% band). We tested the coronagraphs both with an internal source and on-sky using MagAOX, the extreme adaptive optics instrument for the Magellan Clay 6.5 m telescope at Las Campanas Observatory. We show good recovery of the off-axis light's PSF shape within 92% and 97% depending on the separation when aligning the inverse set of PIAA lenses. We demonstrate sub-lambda/D IWAs of about 0.74 lambda/D in 875 and 0.76 lambda/D in z'. We reach average raw contrasts within 1 and 5 lambda/D with the internal source of about 1.6e-3 in 875 and 1.3e-3 in z'. These are mainly limited by the focal plane mask manufacturing errors, jitter, and residual quasi-static speckles in MagAO-X. We also show on-sky average raw contrasts within 1 and 5 lambda/D of about 1.4e-2 in 875 and 7.8e-3 in z'. These are likely limited by wavefront control, low-order aberrations, and poor observing conditions. Future work will improve the design and manufacturing processes of the focal plane masks to improve robustness and reach deeper contrast, as well as integrate focal plane wavefront control for non-common path aberrations correction.

The Tully-Fisher (TF) and Fundamental Plane (FP) relations are widely used to infer extragalactic distances and peculiar velocities, enabling measurements of large-scale velocity statistics and cosmological parameters. Using the Millennium-TNG hydrodynamical simulation, we assess the accuracy of these methods in the presence of realistic galaxy formation physics. We find that, while the 2-point statistics of velocities are reliably inferred on scales larger than $\sim10\,\hMpc$, significant systematic deviations arise on smaller scales. These deviations originate from spatially correlated residuals in the TF and FP relations, driven by correlations between galaxy structural properties, star-formation history, and the local environment. As a result, TF- and FP-inferred velocity fields exhibit spurious correlations with the galaxy density field that cannot be explained by random scatter alone. We show that extending the TF and FP relations to include additional galaxy properties -- such as star formation rate, gas mass, and stellar mass -- mitigate these environmental correlations, particularly for late-type galaxies. Our results demonstrate that galaxy formation physics induces significant systematics in peculiar velocity measurements on non-linear scales, and that neglecting these effects may bias cosmological analyses.

Enhanced inverse Compton (IC) losses at high redshift steepen diffuse radio spectra in galaxy clusters, making low-frequency (~100 MHz) observations favorable. However, low-frequency studies often lack the resolution needed to locate particle acceleration sites or separate diffuse emission from radio galaxies. In this paper, we unveil the properties of the radio relic in the distant cluster PSZ2G091.83+26.11 (z=0.822) by resolving the acceleration site and inspecting the downstream region. Using the European LOFAR (ILT) at 145 MHz, we study a radio relic at (sub-)arcsecond resolution for the first time below 1 GHz, complemented by arcsecond-resolution VLA data at higher frequencies. We confirm the diffuse emission is not a radio galaxy. A spectral index gradient toward the cluster center matches previous 5'' maps. High-resolution 0.4'' and 1.9'' images reveal emission ahead of the shock, connecting the relic to a radio galaxy. 1.9'' profiles across the downstream at 145 MHz and 3.0 GHz follow a log-normal magnetic field distribution. The 145 MHz shock surface shows a sharp discontinuity at the same location of a change in electron density, Rotation Measure, and fractional polarization, likely tied to magnetic field changes. Finally, we find hints of redshift evolution of the radio power versus cluster mass correlation. The impressive angular resolution achievable by the LOFAR long baselines is opening an unprecedented view of the low energetic plasma in galaxy clusters. This is extremely significant in the case of high-redshift clusters, where radio emission at low frequencies is less affected by energy losses but its detection is strongly limited by poor resolution.

Line intensity mapping provides a statistical approach to tracing the large-scale distribution of matter in the Universe. We apply the HI intensity mapping technique to interferometric data from the MeerKAT International GHz-Tiered Extragalactic Explorations (MIGHTEE) Survey, analysing 17.5 hours of a single pointing in the COSMOS field, using a 60 MHz sub-band in the frequency range 1332 - 1392 MHz ($0.02 \lesssim z \lesssim 0.07$). Using a delay-spectrum-based estimator, we measure the HI power spectrum on sub-megaparsec scales and compare it directly to the power spectrum inferred from a catalogue of individually detected HI galaxies in the same field. After mitigating low-level broadband contamination through conservative outlier flagging in the three-dimensional power spectrum, cross-correlation of time-split visibilities yields a statistically significant detection on scales $3 \lesssim k \lesssim 20 \, \mathrm{Mpc}^{-1}$ with a total signal-to-noise ratio of $\sim 13$. Over this range, the power spectra obtained from visibilities and detected galaxies are consistent within uncertainties and have comparable amplitudes of order $10^{-2}$ - $10^{-1}$ $\mathrm{mK}^2 \mathrm{Mpc}^3$. End-to-end validation is performed by propagating detected galaxies through the power spectrum estimator via both direct intensity-field construction and simulated visibilities, demonstrating agreement up to $k \sim 20 \ \mathrm{Mpc}^{-1}$, beyond which measurements become noise-dominated. A statistically significant correlation is also observed between the data and the simulated visibilities from the detected HI galaxies, which should be free of systematics. These results provide a self-consistent validation of interferometric HI intensity mapping at low redshift and demonstrate agreement with galaxy-based measurements within the same cosmological volume.

The era of large astronomical surveys generates massive image catalogs requiring efficient and secure access, particularly during pre-publication periods where data confidentiality and integrity are paramount. While Findable, Accessible, Interoperable, and Reusable (FAIR) principles guide the eventual public dissemination of data, traditional security methods for restricted phases often lack granularity or incur prohibitive performance penalties. To address this, we present a framework that integrates a flexible policy engine for fine-grained access control with a novel GPU-accelerated implementation of the AES-GCM authenticated encryption protocol. The novelty of this work lies in the adaptation and optimization of a parallel tree-reduction strategy to overcome the main performance bottleneck in authenticated encryption on GPUs: the inherently sequential Galois/Counter Mode (GCM) authentication hash (GHASH). We present both the algorithmic adaptation and its efficient execution on GPU architectures. Although similar parallelization techniques have been explored in cryptographic research, this is, to our knowledge, the first demonstration of their integration into a high-throughput encryption framework specifically designed for large-scale astronomical data. Our implementation transforms the sequential GHASH computation into a highly parallelizable, logarithmic-time process, achieving authenticated encryption throughput suitable for petabyte-scale image analysis. Our solution provides a robust mechanism for data providers to enforce access policies, ensuring both confidentiality and integrity without hindering research workflows, thereby facilitating a secure and managed transition of data to public, FAIR archives.

We present a computational framework for galactic evolution based on a coupled stochastic nonlinear oscillator, implemented with the \textbf{Stochastic Hopf Engine}. Gas density ($G$) and star formation rate ($S$) co-evolve through a supercritical Hopf bifurcation, capturing the transition from quiescent stability to merger-driven starbursts. Scatter in dark matter halo properties, modeled as multiplicative noise via the \textbf{Euler--Maruyama method}, broadens the bifurcation into a regime where noise-induced bursts occur below the deterministic threshold. Simulations reveal a periodic signature, the \textbf{Galactic Heartbeat}, emerging as a deterministic limit cycle validated by the \textbf{data3} resonance peak in the star-formation spectrum. A radial reduction yields an effective \textbf{Fokker--Planck equation} for burst amplitude; its stationary solution matches numerical PDFs, providing statistical closure. Including differential shear $\Omega(r)$ and spatially varying bifurcation fields reproduces spiral morphologies and AGN-driven quenching. Driving the growth parameter sub-critical ($r_{agn} < 0$) yields ``Red and Dead'' cores via attractor collapse. Dark matter halo scatter suppresses mean star formation while enhancing intermittency, offering a minimal yet interpretable framework linking local feedback and global potentials to macroscopic galactic evolution.

Transiting extrasolar planets are extraordinarily valuable for understanding the characteristics and formation of planets, because they are the only exoplanets whose physical and orbital properties can be measured to high precision. Thousands are now known, and it is important to maintain a database of them for use by the scientific community. TEPCat performs this task: it is a critical compilation of the physical and observable properties of the known transiting planetary systems. This work introduces the motivation for TEPCat, its scope, contents, and implementation. Example plots of interesting quantities are constructed. The classification of planets and of the eclipse features in their light curves is discussed. TEPCat is maintained and freely available online at this https URL

Galaxy models comprising several components (including dark matter) that are bound by the self-consistently generated gravitational field are readily constructed from distribution functions (DFs) that are analytic functions of the action integrals J. We explain why such models have unphysical velocity distributions unless the DFs of hot components satisfy certain conditions as J_\phi -> 0. We show how DFs for both isotropic and radially biased spherical systems can be constructed with specified f(J). We show how to construct DFs for flattened systems with significant velocity anisotropy. Construction of self-consistent models rather than populations that are confined by an external potential leads to the conclusion that radially-biased spherical systems are generically unstable to quadrupolar perturbations. Chaos is likely key to maintenance of these constraints during adiabatic disc growth.

Precise empirical estimates of stellar radii have revealed that the radii of certain low-mass stars are inflated relative to stellar structure predictions: the largest inflations occur in magnetically active stars. Theoretically, the radii of magnetically active stars are in some cases found to be 'hyper-inflated' to roughly double the radius of a non-magnetic star with equal mass. Here we ask, do data exist which could allow us to search for empirical evidence in support of hyper-inflated stars? A photometric study of 44 eclipsing binaries in the Kepler field by Cruz et al. may help us in our search. The Cruz et al. study, although subject to large uncertainties, hints at the presence of hyper-inflation in some of the 88 stars in their sample. Their data enable us to set theoretical limits on the maximum strength Bc of magnetic fields inside their sample stars. According to our magneto-convective model, the average empirical inflations found from analysis of the Cruz et al. data can be replicated if Bc approx. 10 kG inside stars with masses greater than ~ 0.6 MSun. On the other hand, in stars with masses less than about 0.4 MSun, our model predicts that the average empirical inflations of the stars may approach hyper-inflated status. Such stars may require significantly stronger internal fields, i.e. Bc approx. 100-300 kG. High-resolution spectroscopy of the Kepler binaries could help to confirm or refute our conclusions.

Coronal plumes are bright, narrow structures rooted in coronal holes that contribute to the solar wind. Their composition, particularly elemental fractionation as a function of first ionization potential (FIP), provides diagnostics of plasma properties and magnetic connectivity. Earlier plume studies of fractionation using low-FIP elements reached conflicting conclusions. Intermediate-FIP elements may provide additional diagnostic insight, since their fractionation is thought to involve processes beyond those affecting low-FIP species. We investigate sulfur (intermediate-FIP element) in plumes to assess the presence of fractionation, its evolution, and its relation to wave activity. We analyzed Solar Orbiter observations of two plumes in an equatorial coronal hole during March--April 2024, using Spectral Imaging of the Coronal Environment (SPICE) to derive the sulfur-to-nitrogen ratio. EUV imaging and magnetograms provided additional context. Data were processed with the open-source Python tool Spectral Analysis Fitting Framework and Reduction of Noise (SAFFRON). Both plumes showed sulfur fractionation that remained constant within uncertainties. The fractionated plasma was co-located with strong magnetic footpoints, in contrast with the surrounding interplume plasma. These results provide the evidence for sulfur fractionation in plumes and suggest, consistent with the ponderomotive force model, wave dynamics in the chromosphere as a driver.

We present the optical follow-up of SNe 2022ywf and 2023zgx, two examples from the Iax subclass of thermonuclear supernova (SN) events. With peak absolute magnitudes of $M_\mathrm{V} = -13.7$ and $-14.4$ mag, respectively, both objects belong to the extremely low-luminosity (EL) population of the class. A common origin of SNe in the Iax subclass is still under debate since the distribution of certain observables may indicate that the extremely low-luminosity explosions form a distinct population. We aim to estimate the physical properties of the two EL objects, including mapping the ejecta structure. We perform spectral tomography on the spectral series of SNe 2022ywf and 2023zgx around their maxima to map the physical properties of the ejecta. Together with the analysis of BgVriz photometry, a wide range of observables can be studied to investigate their distribution against luminosity. The constrained chemical abundances of the ejecta are compared to the predictions of the hydrodynamic simulations with similar peak luminosities. Constant abundances provide a good match for the distribution of chemical elements for both SNe 2022ywf and 2023zgx. The discrepancies compared to the least luminous pure deflagration model N5def_hybrid are minor, especially at post-maximum epochs. The two SNe also share similar characteristics in their constrained density structures, as well as the evolution of the photosphere. The analysis supports the assumption that pure deflagration models can reproduce the main characteristics of SNe Iax, even for the EL population. The presented indirect observational evidence indicates that these objects show similar intrinsic properties to the relatively luminous Iax sample and fit into the velocity distribution of the subclass.

We derive a Lorentz-covariant spectral universality for stationary stochastic fields in Minkowski spacetime. We show that no covariant local mapping can relate temporal and spatial power spectra in more than one spatial dimension. For Lorentz homogeneous spectra, the temporal index is symmetry protected, observer invariant, and offset from the spatial index by a universal geometric factor set by effective momentum space dimensionality. We show how spectral universality breaks down for anisotropic scaling and dispersion dominated spectra, establishing the necessity of a Lorentz-covariant formulation of relativistic spectral inference.

We present an analytical treatment of Axion-Like-Particle (ALP)--photon mixing with extragalactic background light (EBL) attenuation for constant, Gaussian-stochastic, and non-Gaussian magnetic field configurations--with direct implications for Very High Energy (VHE) gamma-ray observations such as LHAASO, HAWC, and CTA experiments. For constant fields, we derive exact probabilities and identify a perturbative plateau regime where photon survival scales as quartic order of magnetic field, isolating the four-point magnetic correlation as a sensitive probe of non-Gaussianity. For Gaussian stochastic fields, we obtain--for the first time--analytical formulas for non-exponential-decay components in the strong-attenuation regime. Contrary to the widely used domain-like model, photon survival is suppressed by 4-6 orders of magnitude, while both conversion and survival probabilities exhibit distinct multi-peak structures from mass-equal resonance, stochastic resonance, and EBL attenuation. Extending to non-Gaussian fields, we show that non-Gaussianity can enhance photon survival by several orders of magnitude relative to the Gaussian case, potentially explaining the unexpectedly VHE photon event observed by LHAASO. Our results demonstrate that stochastic magnetic fields cannot be reduced to domain-like coherence without losing essential physics, and that VHE gamma-ray spectra encode observable information about both the power spectrum and non-Gaussian structure of intergalactic magnetic fields--critical as next-generation observatories push toward PeV sensitivities.

While recent planet-formation models broadly reproduce the observed population of super-Earths and mini-Neptunes, as well as the bimodal radius distribution (the ``radius valley''), it remains unclear whether all these planets share a common rocky composition (a single popoulation of planets) or instead comprise two distinct populations -- rocky planets and icy planets (two populations of planets). The inferred eccentricity-radius relation, which shows a modest peak near the radius valley, provides a useful diagnostic for distinguishing between these scenarios. Here we use N-body simulations to examine how the radii and eccentricities of close-in planets depend on the masses and orbital configurations of their progenitor protoplanets. We find that final planetary eccentricities scale with the system initial Safronov number. In two-population systems, energy equipartition between rocky and relatively more massive icy protoplanets creates a strong eccentricity contrast between the two groups, which appears as a peak near the radius valley. This signature does not appear if planetary systems are composed exclusively of rocky planets (with or without H-rich atmospheres), as assumed in photoevaporation and core-powered mass loss models. Because the eccentricity-radius relation traces a dichotomy in the underlying protoplanet mass distribution -- most plausibly arising from formation at different disk locations -- our results suggest that a significant fraction of mini-Neptunes are water-worlds. The observed radius and eccentricity distributions may reflect a mixture of systems that host exclusively rocky planets, systems dominated by icy planets, and systems with both rocky and icy planets.

Transient X-ray obscuration in Seyfert 1 galaxies is thought to arise from clumpy accretion-disk winds near the broad-line region (BLR), but the wind structure and its short-timescale variability are difficult to measure because high-resolution spectra are often suppressed during deep low states. We analyse a coordinated XMM-Newton/NuSTAR campaign on Mrk 335 in June 2021, complemented by long-term Swift monitoring, which captured the source in an intermediate-flux state that preserves strong RGS absorption features. We first model the broadband spectral energy distribution to determine the ionising continuum and then perform self-consistent photoionisation modelling of the RGS spectra. The stacked RGS spectrum requires three photoionised absorbers with time-averaged log xi approx 3.63, 3.10, and 2.01 and outflow velocities |v_out| approx 5820, 3210, and 2140 km/s. Their properties are broadly consistent with the three-phase obscurer reported in the 2009 intermediate state, indicating recurring multi-phase obscuration over decade timescales. Using five consecutive RGS observations, we track the wind evolution on day timescales and find strong variability in column density and ionisation in all phases, together with smaller but coherent changes in outflow velocity. During a flare, the low-ionisation phase shows an extreme drop in N_H, and the subsequent epoch exhibits an increase in outflow velocity in all phases, consistent with rapid restructuring and possible radiative acceleration in a clumpy wind. The high-ionisation phase responds most directly to changes in the ionising luminosity, while the lowest-ionisation phase shows at most a delayed response. Order-of-magnitude constraints place the obscurer at BLR scales (approx 10^3-10^5 R_g), and simple continuity arguments suggest kinetic power that can reach the percent level of L_bol for plausible estimates of geometry and clumpiness.

Primordial magnetic fields (PMFs) generated in the early Universe may leave observable imprints in the present-day large-scale structure. However, it remains unclear on which spatial scales primordial signatures can survive the nonlinear processes accompanying structure formation. The aim of this study is to investigate the evolution of PMFs during gravitational collapse and to determine the spatial scales on which primordial signatures can persist. We perform a suite of high-resolution direct numerical simulations of self-gravitating, magnetized halos. By varying the viscosity, we probe different Reynolds-number regimes and follow the coupled evolution of gravitational collapse and magnetohydrodynamic turbulence. At sufficiently high Reynolds numbers, turbulence generated during collapse triggers the onset of a small-scale dynamo, which amplifies magnetic energy below the Jeans scale and modifies the magnetic energy spectrum significantly. Whether dynamo amplification dominates the magnetic field evolution is determined by the competition between the dynamo growth time and the free-fall time. Our results highlight the importance of resolving the Jeans scale and the associated turbulent inertial range in cosmological MHD simulations to accurately capture the interplay between gravitational compression and dynamo amplification and to assess which structures retain memory of primordial fields.

The construction of Dyson spheres, megastructures designed to capture the total radiative output of stars, can be one of the most compelling techno-signature scenarios for advanced extraterrestrial civilizations. By considering equilibrium temperatures, we investigate the luminosities and fluxes of Dyson spheres built around two promising classes of host stars: white dwarfs and red M-dwarfs. Using radiative balance arguments and representative stellar parameters, we compute the temperature-radius relationship for full energy interception and place these hypothetical structures on the Hertzsprung-Russell (H-R) diagram to assess their observational signatures. Our results show that Dyson spheres around white dwarfs produce cooler and fainter blackbody emissions, peaking in the near- to mid-infrared, while those around M-dwarfs radiate more strongly but at longer wavelengths. In both cases, the equilibrium temperature decreases as R_ D^-1/2, while the total luminosity and observed bolometric flux remain fixed by the stellar output. These findings highlight the astrophysical suitability of low-luminosity stars as Dyson sphere hosts and provide practical constraints for future techno-signature searches using infrared surveys.

The recent detection of GRB 250702B, the longest gamma-ray burst observed to date with prompt emission lasting $\sim 2.5\times 10^4$ seconds, challenges the conventional collapsar model. Its remarkable features--including an extraordinary X-ray flare at $\sim 1.3$ days post-detection, a late-time transition from steep to shallow decay in the X-ray afterglow, and hard spectra extending from keV to MeV energies--point to a novel progenitor. Here we show that these multiwavelength signatures can be consistently explained by a relativistic jet powered by successive partial tidal disruptions of a white dwarf (WD) by an intermediate-mass black hole (IMBH). By modeling the time-dependent accretion rate from repeated partial disruptions and the resulting jet evolution, we show that the external forward and reverse shocks account for the long-term X-ray, near-infrared, and radio afterglow, whereas the luminous X-ray flare originates from internal energy dissipation caused by collisions between fast and slow relativistic ejecta associated with the final complete disruption. Our findings establish IMBH-WD tidal disruption events as a viable engine for ultra-long GRBs.

The bright gamma-ray blazar S5 1044+71 has been identified as showing very significant quasi-periodic oscillations in the Fermi-LAT data in recent studies, with a periodicity of about 3 years. With the completion of a new gamma-ray cycle, we aim to revisit the periodicity in Fermi-LAT data, and analyze all available multi-wavelength (MWL) data to search for possible correlations and time-lags. These observations will be used to test for the compatibility of the observed periodicity with a precessing jet from the supermassive black hole. We analyze data from Fermi-LAT, NuSTAR, Swift, AstroSat, ASAS-SN, ZTF, Pan-STARRS, and NEOWISE. In addition we present an analysis from historical observations from Palomar and Pulkovo. Single-band spectral variability, MWL correlations, and cross-correlations are computed. We then model the Fermi-LAT light curve with a precessing jet model, providing constraints on the geometry of the system and providing the evolution of the Doppler factor with time. The latter is used as input for MWL fitting of the spectral energy distribution. We confirm previous claims on the existence of a periodic gamma-ray signal. We detect significant spectral variability in gamma-ray, X-rays, and optical/UV data. We detect significant correlation between low-energy (infrared/optical/ultraviolet) data and gamma-rays, with a correlation index of about 1; the correlation between X-rays and gamma-ray is milder, with a correlation index of about 0.3. We do not detect any significant time-lag between bands. The Fermi-LAT light curve is successfully fit by a precessing jet model. The fit to the spectral energy distributions indicate that S5 1044+71 is a typical blazar, in which the gamma-ray emission is located beyond the broad-line region. All MWL observations we present in this work are consistent with the existence of a precessing relativistic jet from the supermassive black hole.

We present a spectroscopic study of photometrically identified extreme emission-line galaxies (EELGs) with observed-frame equivalent widths (EWs) >5000 A of either H alpha or H beta + [OIII] in the CEERS legacy deep field utilizing JWST NIRSpec spectroscopy from the CAPERS, RUBIES, THRILS and CEERS surveys. This master sample allows for performance tests of photometric selections and unveils what types of sources, either AGN or young star formation, were producing excessive ionizing radiation in the early Universe. We identify AGN through broad H alpha emission-lines and report 6 new broad-line AGN at 3.5<z<7 identified by the deep (~8 hr) G395M THRILS survey. We investigate the photometrically selected EELGs in a color-color plot designed for ``Little Red Dot'' selection and demonstrate that it effectively removes AGN with non-extreme lines from the sample. EELGs with and without broad lines show similar optical line ratios. We compare emission-line morphology to EWs and continuum morphologies and find that [OIII] morphology is more compact at higher EW. ~10% of photometrically selected EELGs have broad Balmer lines, jumping to 35% in deep spectroscopy which indicates a significant fraction of photometrically selected EELGs may host AGN. However, many AGN selected as EELGs have incorrectly high photometric EWs. For sources with extreme emission-line EWs that pass our photometric criteria and host an AGN, we find that the narrow H alpha component dominates over the broad, especially in the highest-EW sources. This implies that even when an AGN is present, it does not dominate the extreme emission.

Using advanced machine learning techniques, we developed a method for reconstructing precisely the arrival direction and energy of ultra-high-energy cosmic rays from the voltage traces they induced on ground-based radio detector arrays. In our approach, triggered antennas are represented as a graph structure, which serves as input for a graph neural network (GNN). By incorporating physical knowledge into both the GNN architecture and the input data, we improve the precision and reduce the required size of the training set with respect to a fully data-driven approach. This method achieves an angular resolution of 0.092° and an electromagnetic energy reconstruction resolution of 16.4% on simulated data with realistic noise conditions. We also employ uncertainty estimation methods to enhance the reliability of our predictions, quantifying the confidence of the GNN's outputs and providing confidence intervals for both direction and energy reconstruction. Finally, we investigate strategies to verify the model's consistency and robustness under real life variations, with the goal of identifying scenarios in which predictions remain reliable despite domain shifts between simulation and reality.

The legacy Hitomi telescope has delivered the precise measurements of the chemical abundances in the Perseus Cluster, covering the Si-group (Si, S, Ar, Ca) and Fe-group elements (Cr, Mn, Ni). In Paper I (Leung et al., ApJ 2025), we examined the role of convection parameters and presented new core-collapse supernova (CCSN) explosion models at solar metallicity, which fit the observed abundance pattern. In this article, we extend our calculation for the stellar evolutionary models and CCSN models of the initial mass $15 - 60M_{\odot}$ and the metallicity $Z = 0 - Z_{\odot}$. The detailed pre- and post-explosion chemical profiles are calculated with a large post-processing network to capture the production of $\alpha$-chain elements (e.g., Si, S, Ar), odd-number elements (e.g., P, K, Cl), and iron-group elements (e.g., Mn, Ni). We study the role of CCSNe in the production of these elements. We compare the galactic chemical evolution model based on the nucleosynthesis yield of the new massive stars and other yield tables from the literature. For each supernova yield, we perform parameter surveys and search for configurations that produce the best-fit model and best-rate model using the Perseus Cluster as the reference. From the survey, we study how individual chemical elements affect the contributions of massive stars and Type Ia supernovae in the cosmic chemical enrichment

The Perseus Cluster has been precisely measured by the legacy Hitomi telescope on the Si-group (Si, S, Ar, Ca) and Fe-group elements (Cr, Mn, Ni). These element abundance ratios provide insight into the typical behaviour of supernovae. In Paper II, we presented new massive star explosion models at various metallicity, assuming spherical explosions. We show that while the fitting is improved, some features (e.g., Ni/Fe) remain to be improved. In this article, we extend our calculation to an aspherical explosion using the jet-induced explosion mechanism. The detailed pre- and post-explosion chemical profiles are calculated with a large post-processing network to capture the production of odd-number elements (V, Mn, Cu) and iron-group elements. We further explore how the jet-driven explosions create the diversity of models which could be compatible with the observed diversity in terms of $^{56}$Ni-mass vs ejecta mass, Ti-V relation, and stellar abundances. Finally, we apply the new collapsar models in the Galactic Chemical Evolution context. We study how the galactic stars, including the Zn-enriched star HE 1327-2326, can put constraints on the relative rates of collapsar and some of its model parameters. We show that collapsar could lead to significant changes in some elements, e.g., Zn. Our study shows that the collapsar is a necessary component to explain multiple elemental trends observed in the Milky Way Galaxy.

We present the deepest systematic search for planets around mid-to-late M dwarfs to date. We have surveyed 8134 mid-to-late M dwarfs observed by TESS with a custom built pipeline and recover 77 vetted transiting planet candidates. We characterize the sensitivity of our survey via injection-recovery and measure the occurrence rate of planets as a function of orbital period, instellation, and planet radius. We measure a cumulative occurrence rate of $1.10\pm0.16$ planets per star with radii $>1\, R_\oplus$ orbiting within 30 days. This value is consistent with the cumulative occurrence rate around early M dwarfs, making M dwarfs collectively the most prolific hosts of small close-in planets. Unlike the bimodal Radius Valley exhibited by close-in planet population around FGK and early M dwarfs, we recover a unimodal planet radius distribution peaking at $1.25\pm0.05 \, R_\oplus$. We additionally find $0.954\pm0.147$ super-Earths and $0.148\pm0.045$ sub-Neptunes per star, with super-Earths outnumbering sub-Neptunes 5.5:1, firmly demonstrating that the Radius Valley disappears around the lowest mass stars. The dearth of sub-Neptunes around mid-to-late M dwarfs is consistent with predictions from water-rich pebble accretion models that predict a fading Radius Valley with decreasing stellar mass. Our results support the emerging idea that the sub-Neptune population around M dwarfs is composed of water-rich worlds. We find no hot Jupiters in our survey and set an upper limit of 0.012 hot Jupiters per mid-to-late M dwarf within 10 days.

Baryogenesis remains an unresolved problem in cosmology, with existing mechanisms facing significant caveats. We show that the effects of primordial black holes (PBHs) on neutrinos produce the lepton asymmetry $\sim 10^{-10}$ which subsequently produces the baryon asymmetry. We consider the Dirac Lagrangian in curved spacetime in local coordinates exhibiting Hermitian pseudo-vector and non-Hermitian vector terms. These terms lead to energy splitting between weakly interacting neutrinos and antineutrinos, resulting in their unequal number densities and hence a lepton asymmetry. While the non-Hermitian effect leads to a non-conserved total probability of neutrinos, the leptogenesis due to gravitational effects of a PBH could be significant until the nucleosynthesis era. This in turn produces baryon asymmetry from the symmetry of lepton and baryon numbers via the sphaleron process in the electro-weak era. We show that in the most conservative scenario, the PBHs of mass $\sim 10^{12}$ g and spin $\sim 0.01$ produce the observed baryogenesis at temperature 130 GeV, when such PBHs are available abundantly. However, massive PBHs also could produce the observed asymmetry, assuming the non/anti-Hermitian vector couplings for neutrino and anti-neutrino get canceled from the Lagrangian, leading the system to be Hermitian.

It is shown that conformal symmetry exists in force-free electrodynamics (FFE) in Minkowski spacetime, a foundational framework for describing magnetospheres around astronomical objects. In force-free magnetospheres, charges are constrained to move along magnetic field lines and experience zero Lorentz force, due to the everywhere perpendicular orientation of electric and magnetic fields. However, a general angle-preserving conformal mapping of force-free fields does not necessarily produce another physically admissible force-free configuration when sources are present. In this work, we demonstrate that such invariance can nevertheless arise for certain choices of the free functions. Specifically, the governing stream equation is shown to be invariant under Möbius transformations. This symmetry reveals a structural linkage between known solutions and, notably, maps the region inside a magnetospheric horizon (the lightsurface) of one solution to the exterior of its dual counterpart, and vice versa.

We identify a fundamental pathology in the likelihood for time delay inference which challenges standard inference methods. By analysing the likelihood for time delay inference with Gaussian process light curve models, we show that it generically develops a boundary-driven "W"-shape with a global maximum at the true delay and gradual rises towards the edges of the observation window. This arises because time delay estimation is intrinsically extrapolative. In practice, global samplers such as nested sampling are steered towards spurious edge modes unless strict convergence criteria are adopted. We demonstrate this with simulations and show that the effect strengthens with higher data density over a fixed time span. To ensure convergence, we provide concrete guidance, notably increasing the number of live points. Further, we show that methods implicitly favouring small delays, for example optimisers and local MCMC, induce a bias towards larger $H_0$. Our results clarify failure modes and offer practical remedies for robust fully Bayesian time delay inference.

Cosmic strings are topological defects arising in a variety of cosmological scenarios, as the Universe undergoes symmetry-breaking phase transitions, whose discovery would offer valuable insight into the high-energy physics that shaped the early Universe. To interpret such a detection, robust theoretical models are essential. The Velocity-dependent One-Scale (VOS) model is particularly prominent: it self-consistently treats the network as a thermodynamic system, characterizing its key properties, and predicting its large-scale evolution. This has recently been extended to include superconducting cosmic strings, which carry additional degrees of freedom, giving rise to the Charge-Velocity dependent One-Scale (CVOS) model. One limitation of the latter model is that it only included loss mechanisms for the charge and current. Here, we extend this model by phenomenologically including a possible energy source mechanism, specifically by allowing current-carrying strings interactions with an external magnetic field. We discuss how this coupling impacts the network's evolution, present and classify the physically allowed scaling solutions for this extended CVOS model, and comment on the different impacts of the external magnetic field on the evolution of the network's charge and current. Under our modeling assumptions, one of the ten physically plausible scaling solution enables the network to gain energy by this mechanism.

Radial gradients of cosmic rays are key parameters for understanding the transport of particles in space. Solar Orbiter, launched on 2020 February 10, approaches the Sun approximately every half year, with a closest perihelion distance of 0.29 au after the end of 2022 during the nominal mission phase. The two double-ended high energy telescopes(HET)onboard the Solar Orbiter measure energetic particles in the energy range between a few MeV/nuc and a few hundred MeV/nuc, which are dominated by anomalous cosmic rays (ACRs) and galactic cosmic rays (GCRs) during solar quiet times. By obtaining the radial gradient of the ACR helium in the inner heliosphere, we advance our understanding of how the transport of the cosmic rays is affected by the particle drift effect and the large-scale magnetic field. The helium observations at Solar Orbiter/HET between 11.1 and 49 MeV/nuc are analyzed. Since we focus on quiet time measurements, we remove the periods of solar energetic particle (SEP) events. The intensities are averaged over the Carrington rotation period. The helium observations from the Proton and Helium Instrument(EPHIN)onboard SOHO were utilized as the baseline to correct the long-term variation caused by the solar modulations. We present the first observation of ACR helium at Solar Orbiter/HET between 2020 February and 2022 July in the inner heliosphere before the sun became fully active. We derive the radial gradient of the ACR helium between 0.3 and 1 au. The averaged radial gradient between 11.1 and 49MeV/nuc is about 22$\pm$4%/au and the averaged value between 11.1 and 41.2MeV/nuc is raised to 32$\pm$8%/au after removing the GCR contribution, which is estimated by a GCR model. In addition, the temporal variation of radial gradients indicates that the gradients are increasing with the enhancement of the solar modulation and the increased tilt angle of the heliospheric current sheet.

The Canadian subatomic physics community establishes its scientific, and thus funding, priorities through periodic Long-Range Plans (LRP). The community is now putting together a new LRP, which will be in effect from 2027 through 2034, with its scope extending through 2041. As part of this process, the Canadian Institute of Nuclear Physics (CINP) has put together a strategic report, following an extensive consultation process. The report describes the broad and ambitious research program undertaken by the Canadian nuclear physics research community, both onshore and abroad, touching on key questions regarding the origin, evolution, and structure of visible matter in the universe. This document provides a grid of different Canadian nuclear physics projects undertaken now and in the future, and their associated timelines. It concludes with specific recommendations for maximizing Canadian scientific output in nuclear physics.

We consider a renormalizable extension of the minimal supersymmetric standard model (MSSM) endowed by an R and a gauged B - L symmetry. The model incorporates chaotic inflation driven by a quartic potential, associated with the Higgs superfields which lead to a spontaneous breaking of U(1)B-L. Consistency with the ACT data is achieved by considering a fractional shift-symmetric Kaehler potential which includes two free parameters (p,N) constrained in the ranges 1.355<p<6.7 and 6x10^-5<N<0.7. An explanation of the mu term of the MSSM is also provided, under the condition that a related parameter in the superpotential is somewhat small. Baryogenesis occurs via non-thermal leptogenesis which is also realized by the inflaton's decay to the lightest and/or next-to-lightest right-handed neutrinos for normal ordered light neutrino masses.

We investigate the conditions under which $\Delta(1232)$ isobars trigger a first-order phase transition within purely hadronic neutron-star matter, using the SW4L relativistic mean-field parametrization. For scalar-vector coupling differences $0.15 \lesssim x_{\sigma\Delta} - x_{\omega\Delta} \lesssim 0.2$ and $x_{\sigma\Delta} \gtrsim 1.3$, the onset of $\Delta^-$ resonances produces a van der Waals-like instability driven by a self-amplifying feedback in the scalar meson sector, in which the $\Delta^-$ particle fraction acts as the order parameter of a Landau-type transition. A Maxwell construction yields a sharp density discontinuity at baryon densities $n_b \sim (1.3$-$2)\,n_0$, separating a $\Delta$-free outer core from a $\Delta$-rich inner core. The resulting neutron-star sequences satisfy all current multimessenger constraints: maximum masses $M_{\rm max} \approx 2.15$-$2.25\,M_\odot$, radii $R_{1.4} \approx 11$-$12$ km, and tidal deformabilities $\Lambda_{1.4} \approx 190$-$480$, compatible with NICER observations and GW170817. We compute, for the first time for a $\Delta$-induced interface, the $\ell = 2$ composition $g$-mode eigenfrequencies, obtaining $\nu_g \sim 400$-$1100$ Hz with gravitational-wave damping times $\tau_g \sim 10^3$-$10^9$ s. These frequencies overlap quantitatively with those predicted for hadron-quark phase-transition interfaces, demonstrating that the mass-radius ``knee'', reduced tidal deformability, and $g$-mode spectrum conventionally regarded as signatures of quark deconfinement can be reproduced by a purely intrahadronic mechanism. This extends the masquerade problem from static observables to the domain of gravitational-wave asteroseismology, implying that a future detection of a discontinuity $g$-mode alone would not suffice to identify quark matter in neutron-star cores.

We present the first statistical study of geomagnetic storm forecasting using in situ data from the STEREO-A spacecraft as a sub-L1 monitor. Between November 2022 and June 2024, STEREO-A crossed the Sun-Earth line, covering longitudinal and radial separations of +/-15° from the Sun-Earth line and 0.01-0.06 au from Earth. This passage provides a unique opportunity to assess future sub-L1 mission concepts by ESA, such as HENON and SHIELD. We identify 32 coronal mass ejections (CMEs) observed by both STEREO-A and L1 spacecraft. Eight of these 32 CME events are first detected at L1, indicating that radial spacecraft separations of up to ~0.05 au do not always yield lead time advantages. Furthermore, we find greater (smaller) gains in lead time when STEREO-A is east (west) of the Sun-Earth line. We develop a baseline methodology for the use of future sub-L1 in situ data to enable time-shifting and real-time modeling of the geomagnetic SYM-H index. This is run continuously over the entire time period, therefore modeling the geomagnetic response of all solar wind structures. Our methodology is empirically motivated and should be considered a first approach in addressing the use of sub-L1 data. Following this methodology, 26 of 47 observed geomagnetic storms are correctly identified from STEREO-A data. Intense events (82%, SYM-H<-100 nT) are well detected, most of which are also associated with an identified CME event. Most SYM-H minima are predicted later (72%) and stronger (58%) than those observed due to biases introduced by our methodology.

The thermodynamics of the $SU(4)$ gauge theory with a single flavor of fundamental quarks is analyzed on the lattice with dynamical fermion simulations, which is the low-energy sector of a realistic, strongly-interacting dark matter model -- the Hyper Stealth Dark Matter. The gravitational wave spectrum from the first-order confinement transition in the early universe is further calculated, where the effect of the dark sea quarks, which decrease the interface tension in the effective potential of the Polyakov loop, is shown numerically to lower the gravitational wave amplitude.

The dark matter (DM) density profile in the innermost region of the Galaxy remains an open question. In particular, while adiabatic growth of the supermassive black hole Sgr A$^\ast$ at the Galactic Center (GC) can induce a 'spike' in central DM density, the existence of such a spike is still under debate. Here we present new constraints on the spike slope $\gamma_{\rm sp}$ using conventional DM indirect detection searches. We first recast existing photon and neutrino line searches, which include the contribution from the GC region, into constraints on the thermally-averaged DM annihilation cross section $\langle\sigma v\rangle$ in the presence of a DM spike. We then derive new bounds on the spike profile for a generic Weakly Interacting Massive Particle (WIMP) DM scenario, where the thermal freeze-out mechanism fixes the annihilation cross-section at $\langle\sigma v\rangle\sim (2-3) \times 10^{-26}~{\rm cm}^3~{\rm s}^{-1}$. We find that for DM annihilation to photons, constraints from Fermi-LAT and MAGIC rule out spike profiles at the GC for a broad range of WIMP DM masses from 10 GeV to 100 TeV. Our result holds even if the photon channel constitutes only $1\%$ of the total annihilation rate. For the neutrino channel, we use the IceCube data to constrain the existence of an extremely steep spike in the $\mathscr{O}(1-10)$ TeV DM mass range. Our analysis can be easily extended to other annihilation channels.