Papers for Monday, Sep 08 2025

OrbDot is a Python package for studying the secular (long-term) evolution of exoplanet orbits from observational data. It employs nested sampling algorithms to fit evolutionary models to any combination of transit and eclipse mid-times, radial velocities, and transit durations. Beyond model fitting, OrbDot offers tools for interpreting results, generating reports on model comparisons, derived tidal decay parameters, predicted precession rates, implications for planetary companions, and more.

The Einstein Probe is revolutionizing time-domain astrophysics through the discovery of new classes of X-ray transients associated with Type Ic-Broad Line supernovae. These events commonly exhibit bright early-time optical counterparts, and sudden afterglow rebrightening within the first week - features that existing models fail to explain. In particular, structured jet and cocoon scenarios are inconsistent with the observed sharp rebrightening and multi-day optical emission, while the refreshed shock model is ruled out due to its inconsistency with collapsar hydrodynamics. Drawing on 3D general-relativistic magnetohydrodynamic simulations, we present the multi-scale angular and radial structure characterizing collapsar outflows. The resulting morphology features episodic, wobbling jets with a "top-hat" geometry, embedded within a smoother global cocoon and disk ejecta angular structure. The wobbling jets give rise to variations in radiative efficiency that can account for the observed alternation between X-ray-dominated and $\gamma$-ray-dominated jet emission. The top-hat structure of individual wobbling jet episodes naturally explains the sudden rebrightening observed when the emission from the top-hat jet cores enters the observer's line of sight. The radial structure is consistent with that inferred from observations of stripped-envelope supernovae. It comprises a mildly relativistic cocoon ($0.3\lesssim\beta\Gamma\lesssim3$) that may power an early ($\sim1\,{\rm day}$) rapidly decaying emission, followed by slower, black hole accretion disk-driven outflows ($\beta\lesssim0.3$), which dominate the slowly evolving optical emission at $t\gtrsim1\,{\rm day}$. This novel multi-component outflow structure provides a unified explanation for the multiband light curves observed in Einstein Probe transients and is likely a common feature of Type Ic-Broad Line supernovae more broadly.

In order to derive unbiased cosmological parameters from Stage-IV surveys, we need models that can predict the matter power spectrum for at least $k\,\lesssim\,10\,h\mathrm{\,Mpc^{-1}}$ with percent-level precision. The main challenge in this endeavour is that baryonic feedback significantly redistributes matter on large scales, but to an unknown degree. Here, we present an improved version of the "resummation" model, which maps observed halo baryon fractions of massive haloes ($M_{\mathrm{500c}}\gtrsim 10^{12.5}\, \mathrm{M_\odot}$) to a flexible suppression signal - i.e. the ratio of baryonic to dark-matter-only (DMO) matter power spectra - using zero free parameters. We apply this model to the FLAMINGO hydrodynamical simulations, obtaining a typical precision of $\lesssim 1\%$ for $k\,\leq\,10\,h\mathrm{\,Mpc^{-1}}$ given mean halo baryon fractions within the spherical overdensity radii $R_{\mathrm{500c}}$ and $R_{\mathrm{200m}}$. When only those within $R_{\mathrm{500c}}$ are available, we still obtain $\lesssim 2\%$ precision. We show that given small-scale stellar mass fractions, the model can be extended to yield $\lesssim 3\%$ precise suppression signals for all scales measured ($k\,\leq\,25\,h\mathrm{\,Mpc^{-1}}$). We also extend the model to redshifts $z>0$. Central to the model is a seemingly mass-independent and feedback-independent relation that allows observed halo masses to be mapped to equivalent DMO halo masses using only observed mean halo baryon fractions, to $\lesssim 1\%$ precision. We demonstrate that this relation can also be used to retrieve the DMO halo mass function from observed halo masses and baryon fractions with percent-level precision, without any assumptions on the strength of feedback. A Python package implementing the resummation model is made publicly available.

The origin of obscuration in Active Galactic Nuclei (AGN) is still a matter of contention. It is unclear whether obscured AGN are primarily due to line-of-sight effects, a transitory, dust-enshrouded phase in galaxy evolution, or a combination of both. The role of an inner torus around the central SMBH also remains unclear in pure Evolution models. We use cosmological semi-analytic models and semi-empirical prescriptions to explore obscuration effects in AGN at 1<z<3. We consider a realistic object-by-object modelling of AGN evolution including different light curves (LCs) composed of phases of varying levels of obscuration, mimicking the possible clearing effects of strong AGN feedback. Evolution models characterized by AGN LCs with relatively short pre-peak obscured phases followed by more extended optical/UV visible post-peak phases, struggle to reproduce the high fraction of obscured AGN at z~2-3 inferred from X-ray surveys. Evolution models characterised by LCs with sharp post-peak declines or persistent or multiple obscuration phases are more successful, although they still face challenges in reproducing the steady drop in the fractions of obscured AGN with increasing luminosity measured by some groups. Invoking a fine-tuning in the input LCs, with more luminous AGN defined by longer optical/UV visible windows, can improve the match to the decreasing fractions of obscured AGN with luminosity. Alternatively, a long-lived central torus-like component, with thickness decreasing with increasing AGN power, naturally boosts the luminosity-dependent fractions of obscured AGN, suggesting that small-scale orientation effects may still represent a key component even in Evolution models. We also find that in our models major mergers and starbursts, when considered in isolation, fall short in accounting for the large fractions of highly obscured faint AGN detected at cosmic noon.

We report the discovery and characterization of a wide binary population in the ultrafaint dwarf galaxy Boötes I using deep JWST/NIRCam imaging. Our sample consists of 52 candidate binaries with projected separations of 7,000 - 16,000 au and stellar masses from near the hydrogen-burning limit to the main-sequence turnoff ($\sim0.1$ - $0.8~{\rm M_\odot}$). By forward-modeling selection biases and chance alignments, we find that $1.25\pm0.25\%$ of Boötes I stars are members of wide binaries with separations beyond 5,000 au. This fraction, along with the distributions of separations and mass ratios, matches that in the Solar neighborhood, suggesting that wide binary formation is largely insensitive to metallicity, even down to [Fe/H] $\approx -2.5$. The observed truncation in the separation distribution near 16,000 au is well explained by stellar flyby disruptions. We also discuss how the binaries can be used to constrain the galaxy's dark matter properties. We show that our detection places new limits on primordial black hole dark matter, finding that compact objects with $M \gtrsim 5~{\rm M_\odot}$ cannot constitute more than $\sim1\%$ of the dark matter content. In contrast to previous work, we find that wide binaries are unlikely to provide robust constraints on the dark matter profile of ultrafaint galaxies given the uncertainties in the initial binary population, flyby disruptions, and contamination from chance alignments. These findings represent the most robust detection of wide binaries in an external galaxy to date, opening a new avenue for studying binary star formation and survival in extreme environments.

The Gaia-Sausage/Enceladus (GS/E) accretion remnant is one of the most important stellar populations in the Milky Way halo. Recent simulation-based work has suggested that the anisotropy profiles of remnants like GS/E decline towards the center and may be well-fit by an Osipkov-Merritt-type distribution function (DF). We study the anisotropy profile of GS/E using a chemically-selected sample of stars from APOGEE DR17 and Gaia. We find that the anisotropy profile of GS/E is high and constant with $\beta \sim 0.9$ beyond 8 kpc, dropping to $\beta \sim 0.4$ at 2 kpc. We fit a two-component Osipkov-Merritt anisotropy profile to the GS/E data, finding that a combination of profiles with scale radii $r_{\mathrm{a}}=2$ kpc and 547 kpc, with a mixture fraction $k_\mathrm{om} = 0.88$ provide a better fit to the data than a constant anisotropy profile. Using this new DF, we re-assess the density profile and mass of the GS/E remnant from a previous work that assumed a contant-anisotropy DF, finding an increase in the derived mass from $1.5\times 10^{8}~\mathrm{M}_{\odot}$ to $2.29 ^{+0.95}_{-0.63}\times 10^{8}~\mathrm{M}_{\odot}$. In general, the combination Osipkov-Merritt DF more satisfactorily matches the kinematics of the GS/E remnant than the constant anisotropy DF, and in the future will form a more reliable basis for modelling the remnant. Additionally, these new constraints on the kinematics of GS/E near the Galactic center are an important measurement for any future theoretical or simulation-based investigation into its nature and origin.

A handful of enigmatic Jupiter-mass objects have been discovered orbiting pulsars. One such object, PSR J2322-2650b, uniquely resembles a hot Jupiter exoplanet due to its minimum density of 1.8 g/cm^3 and its ~1900 K equilibrium temperature. We use JWST to observe its emission spectrum across an entire orbit. In stark contrast to every known exoplanet orbiting a main-sequence star, we find an atmosphere rich in molecular carbon (C3, C2) with strong westward winds. Our observations open up a new exoplanetary chemical regime (ultra-high C/O and C/N ratios of >100 and >10,000 respectively) and dynamical regime (ultra-fast rotation with external irradiation) to observational study. The extreme carbon enrichment poses a severe challenge to the current understanding of "black widow" companions, which were expected to consist of a wider range of elements due to their origins as stripped stellar cores.

We present radio and X-ray observations of the recently discovered $z=6.13$ radio-powerful quasar RACS J032021.44$-$352104.1 using uGMRT, ATCA, LBA, and Chandra. The observed radio properties are in line with what is typically observed in high-$z$ radio quasars ($\alpha_{\rm r}=0.72\pm 0.02$ and L$_{\rm 1.4GHz}=5.8 \pm 0.9 \times 10^{26}$ W Hz$^{-1}$). Despite the relatively low X-ray flux observed $F_{\rm 0.5-7.0 keV}=2.3\pm0.5 \times 10^{-14}$ erg sec$^{-1}$ cm$^{-2}$, the intrinsic luminosity in the 2-10 keV rest frame is markedly high, $L_{\rm 2-10 keV}=1.8^{+1.1}_{-0.7} \times 10^{46}$ erg sec$^{-1}$, making RACS J032021.44$-$352104.1 one of the most luminous quasars currently known at $z>5.5$. The high X-ray luminosity is largely driven by an extrapolation to energies below the observable X-ray window with Chandra and the slope derived in the 0.5-7 keV band (or 3.5--50 keV in the rest-frame; $\Gamma_{\rm X}=3.3\pm0.4$). By analysing the overall spectral energy distribution of the quasar we found that the remarkably soft X-ray emission: (1) cannot be produced by relativistic jets, even when relativistic boosting is considered; and (2) is consistent with expectations for a super-Eddington accreting SMBH. If such a high accretion rate was confirmed, this source would be a unique laboratory to study high accretion in the early Universe and could help resolve some challenges inherent in early black hole growth paradigms.

Episodic mass accretion is the dominant mechanism for mass assembly in the proto-stellar phase. Although prior optical time-domain searches have allowed detailed studies of individual outbursts, these searches remain insensitive to the earliest stages of star formation. In this paper, we present the characterization of two FU Orionis (FUor) outbursts identified using the combination of the ground-based, near-infrared Wide-field Infrared Transient Explorer (WINTER) and the space-based, mid-infrared NEOWISE survey. Supplemented with near-infrared spectroscopic follow-up, we show that both objects are bona fide FUor type outbursts based on i) their proximity to star-forming regions, ii) large amplitude (2-4 magnitudes) infrared brightening over the last decade, iii) progenitor colors consistent with embedded (Class I) protostars, and iv) "mixed-temperature" infrared spectra exhibiting characteristic signatures of cool outer envelopes and a hot inner disk with a wind. While one source, WNTR24-cua, is a known FUor which we independently recover; the second source, WNTR24-egv, is a newly confirmed object. Neither source is detected in contemporaneous ground-based optical imaging, despite flux limits $\gtrsim 100\times$ fainter than their infrared brightness, demonstrating the capabilities of WINTER to identify heavily obscured young stellar object (YSO) outbursts. We highlight the capabilities of the Galactic Plane survey of the recently commissioned WINTER observatory in addressing the poorly understood FUor population with its unique combination of real-time detection capabilities, multi-color sensitivity, weekly cadence, and wide area coverage.

We review our current understanding of nuclear stellar discs (NSDs), rotating, and flattened stellar structures found in the central regions of both early- and late-type galaxies. We examine their demographics, kinematics, stellar populations, metallicity gradients and star formation histories. We derive scaling relations linking NSDs to properties of their host galaxies, and compare them with analogous relations for nuclear star clusters. The relationship between NSDs and other central galactic components, including nuclear rings, nuclear bars, and nuclear star clusters, is explored. The role of NSDs as tracers of the secular evolution of barred galaxies is highlighted, emphasising how they can be used to constrain properties of galactic bars such as their ages. Special attention is given to the Milky Way's NSD, which serves as a unique case study thanks to its proximity and the ability to resolve individual stars. The review covers the Milky Way's NSD structure, kinematics, dynamics and stellar content, addressing ongoing debates about the presence of a nuclear bar and implications of the latter for central gas dynamics. We argue that NSDs form by in-situ star formation, most of them because of bar-driven gas inflow, but possibly in some cases because of external acquisition of gas during a gas-rich merger. The review concludes by outlining open questions, future research directions and the exciting prospects provided by upcoming observational facilities.

We report Giant Metrewave Radio Telescope (GMRT) \hii\ imaging of NGC\,4141, the host galaxy of FRB\,20250316A at $z=0.0063$. Our GMRT \hii\ images have spatial resolutions, at $z\approx0.0063$, of $\approx0.48-8.0$~kpc, and find evidence for (i)~a companion galaxy, LEDA\,2582852, to the south-west, (ii)~a nearby (27-kpc distant) H{\sc{i}} cloud to the south-west, (iii)~disturbances in the H{\sc{i}} distributions of both NGC\,4141 and LEDA\,2582852, and (iv)~high H{\sc{i}} column densities in the south-western outskirts of NGC\,4141. A Sloan Digital Sky Survey spectrum shows evidence for a low metallicity and a high star-formation rate (SFR) surface density activity in the south-western disk of NGC\,4141, while H$\alpha$-based SFR estimates over the last 10~Myr are higher than radio-based SFRs over the last 100~Myr. The above evidence indicates that NGC\,4141 has recently acquired metal-poor gas, via either a merger or accretion, that resulted in the south-western starburst and that may have also triggered large-scale star-formation activity in NGC\,4141, resulting in the formation of the stellar progenitor of FRB\,20250316A and the other transients. Our highest-resolution (480~pc) GMRT H{\sc{i}} 21\,cm image finds no H{\sc{i}} 21\,cm emission from the location of FRB\,20250316A or the nearby star-forming region, suggesting that most of the H{\sc{i}} here has been either ionized or converted into the molecular phase. Our non-detection of continuum emission at the location of FRB\,20250316A yields the $3\sigma$ upper limit $<3.2\times10^{25}$~erg~s$^{-1}$~Hz$^{-1}$, on the 1.4~GHz specific luminosity of a putative persistent radio source associated with FRB\,20250316A, one of the strongest constraints on the radio luminosity of such an associated persistent radio source.

Neptunes and sub-Neptunes are typically modeled under the assumption that the interior is adiabatic and consists of distinct layers. However, formation models indicate that composition gradients can exist. Such composition gradients can significantly affect the planetary thermal evolution. In non-convective layers, the heat transport is governed by multiple processes. We investigate how the evolution and internal structure of Neptunes and sub-Neptunes is affected when considering non-convective layers and the sensitivity of the results on the assumed thermal conductivity. Methods. We simulate the planetary evolution by considering thermal transport via radiation, electrons, and vibrational conductivity. We consider planetary masses of 5, 10 and 15 ME, three different initial energy budgets, and two different primordial composition profiles. We find that the assumed conductivity significantly affects the planetary thermal evolution. We show that the commonly used conductivity assumption is inappropriate for modeling this planetary type. Furthermore, we find that the inferred radii deviate by ~20% depending on the assumed conductivity. The uncertainty on the primordial entropy in planets with non-convective layers leads to a difference of ~25% in the radii. This shows that the theoretical uncertainties are significantly larger than the observed ones, and emphasizes the importance of these parameters. We conclude that the characterization and modeling of intermediate-mass gaseous planets strongly depend on the modeling approach and the model assumptions. We demonstrate that the existence of composition gradients significantly affects the inferred radius. We suggest that more data on thermal conductivities, particularly for partially ionized material and mixtures, as well as better constraints on the primordial thermal state of such planets are necessary.

We have used the Green Bank Telescope to search for H{\sc{i}} 21\,cm emission from 30 Green Pea galaxies (GPs) at $z\approx0.012-0.045$, obtaining 7 detections of H{\sc{i}} 21\,cm emission and 17 upper limits on the H{\sc{i}} mass. Including GPs from the literature, we obtain a sample of 60 GPs at $z<0.05$, with 19 detections and 41 non-detections of H{\sc{i}} 21\,cm emission, and with stellar masses in the range $10^6-10^9\,\rm{M_{\odot}}$. We use the line luminosity ratio O32~$\equiv$~[O{\sc iii}]$\lambda 5007+\lambda 4959$/[O{\sc ii}]$\lambda$3727,3729 as an indicator of Lyman continuum (LyC) leakage, and examine the dependence of the H{\sc{i}} properties of the 60 GPs on the O32 ratio. We obtain a far higher H{\sc{i}} 21\,cm detection rate ($\approx53^{+16}_{-13}$\%) for the 32 GPs with O32~$<10$ than that ($7.1^{+9.4}_{-4.6}$\%) for the 28 GPs with O32~$>10$. We find statistically significant evidence that the H{\sc{i}} mass, the H{\sc{i}}-to-stellar mass ratio, and the H{\sc{i}} gas depletion timescale of GPs with O32~$>10$ are lower than the corresponding values for GPs with O32~$<10$. Earlier studies have shown that galaxies with O32~$>10$ tend to show significant LyC leakage: our results indicate that this is due to the lack of H{\sc{i}} in such galaxies, with most of the H{\sc{i}} consumed in the starburst. Our results further suggest that H{\sc{i}} 21\,cm studies of the galaxies that reionized the Universe at $z\gtrsim6$ are likely to find an anti-correlation between the H{\sc{i}} 21\,cm and Ly$\alpha$ emission signals, due to the paucity of H{\sc{i}} in the strongest LyC and Ly$\alpha$ leakers.

Local galaxies follow scaling relations between mass and stellar population properties such as age and metallicity, which encode key information on their evolutionary histories. We revise these relations using the largest spectroscopic dataset from SDSS DR7 (0.005<z<0.22), improved Stellar Population Synthesis (SPS) models, aperture-corrections, and statistical weights to account for selection biases. In a Bayesian framework, we estimate stellar masses, mean ages, and metallicities by comparing spectral indices and photometry with composite SPS models. We adopt updated prescriptions for Star Formation Histories (SFH) and Chemical Enrichment Histories (CEH), while also testing different models and priors. We measure light-weighted ages for 354,977 galaxies (SNR>10) and metallicities for 89,852 galaxies (SNR>20), analyzing their dependence on stellar mass. Key findings include: i) A revised bimodal mass-age distribution, with a young sequence at low mass and an old sequence at high mass, partly overlapping in mass and transitioning at 10^10.8 solar masses. ii) A Mass-Metallicity Relation (MZR) shifted upwards by 0.2 dex relative to previous works. Aperture corrections lower masses, ages, and metallicities in a mass-dependent way, enhancing the young sequence and steepening the MZR. iii) Using Halpha-based SFRs, we found that while star-forming/young and quiescent/old correspondences generally hold, exceptions exist for many galaxies. Quiescent galaxies show a flatter, less scattered MZR than star-forming ones, with convergence at high mass. iv) SPS assumptions strongly affect our results, particularly SFHs and CEHs. These revised relations provide new benchmarks for galaxy evolution studies and simulations. Systematic uncertainties of 0.15 dex may arise from aperture biases and SPS modelling choices, highlighting the need for consistent assumptions when comparing observations and models.

For synchrotron radiation from relativistic electrons having a power-law energy distribution with a power-law index $p$ in an optically thin medium with a locally uniform magnetic field, it is generally adopted that the spectral index $\alpha = (p-1)/2$ and the degree of linear polarisation $\Pi_{\rm L,pl} = (p +1)/(p+7/3)$, and hence that $\Pi_{\rm L,pl} = (\alpha +1)/(\alpha+5/3)$. These ($\alpha$, $\Pi_{\rm L,pl}$; $p$) relations are derived assuming that the electrons have an isotropic momentum distribution and a power-law energy distribution, and they have been used, almost universally, in the interpretation of polarimetry observations. In this study, we assess the validity of the ($\alpha$, $\Pi_{\rm L,pl}$; $p$) relations in different scenarios, such as anisotropic electron momenta and non-power-law distributions of electron energy. We calculate the synchrotron radiation and polarisation spectra for power-law, kappa and log-parabola electron-energy distributions, with isotropic and two anisotropic (beamed and loss cone) electron-momentum distributions. Our calculations show that when the electron momenta are isotropic, the usual ($\alpha$, $\Pi_{\rm L,pl}$; $p$) relations are generally applicable. However, if the electrons are anisotropic, the usual ($\alpha$, $\Pi_{\rm L,pl}$; $p$) relations could break down. Applying the usual ($\alpha$, $\Pi_{\rm L,pl}$; $p$) relations indiscriminately without caution on anisotropy in the electron momentum distribution, would lead to incorrect interpretations of polarimetry data.

As Radial velocity (RV) spectrographs reach unprecedented precision and stability below 1 m/s, the challenge of granulation in the context of exoplanet detection has intensified. Despite promising advancements in post-processing tools, granulation remains a significant concern for the EPRV community. We present a pilot study to detect and characterise granulation using the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph. We observed HD166620, a K2 star in the Maunder Minimum phase, intensely for two successive nights, expecting granulation to be the dominant nightly noise source in the absence of strong magnetic activity. Following the correction for a newly identified instrumental signature arising from illumination variations across the CCD, we detected the granulation signal using structure functions and a one-component Gaussian Process (GP) model. The granulation signal exhibits a characteristic timescale of 43.65$\pm$15.8 minutes, within one $\sigma$, and a standard deviation of 22.9$\pm$0.77 cm/s, with in three $\sigma$ of the predicted value. By examining spectra and RVs as a function of line formation temperature , we investigated the sensitivity of granulation-induced RV variations across different photospheric layers. We extracted RVs from various photospheric depths using both the line-by-line (LBL) and cross-correlation function (CCF) methods to mitigate any extraction method biases. Our findings indicate that granulation variability is detectable in both temperature bins, with the cooler bins, corresponding to the shallower layers of the photosphere, aligning more closely with predicted values.

Observations of gravitational waves from binary black hole mergers, including the recent signals GW231123 and GW230529, have revealed multiple progenitor black holes in the so-called upper and lower mass gaps, respectively. It is generally assumed that massive stars cannot form black holes in the upper mass gap because pair instabilities in the late stage of stellar evolution disrupt the stars, whereas the lower mass gap refers to the gap between the maximum allowed neutron star mass and the smallest black hole mass expected to form in supernova explosions. Here we explore a "premature collapse" scenario in which upper mass gap stars collapse and form black holes before they reach the late stage of stellar evolution. The mechanism for triggering a premature collapse is the capture of a smaller black hole, possibly primordial in nature. A similar capture scenario can occur to produce black holes in the lower mass gap. At least for massive stars, typical stellar rotation rates would likely result in rapidly rotating black holes in such a scenario, naturally explaining the rapid spins inferred from GW231123. Even though our estimates hinge on several parameters with rather large uncertainties, they suggest that, at least in galactic disks, the likelihood of such a capture is small for stars in the upper mass gap, but may lead to a significant population of black holes in the lower mass gap and, in fact, even below the lower mass gap.

The extreme variability of blazars, in both timescale and amplitude, is generally explained as the effect of a relativistic jet closely aligned to the observer's line-of-sight. Due to causality arguments, variability characteristics translate into spatial information about the emitting region of blazars. Since radiation at different wavelengths is emitted in different parts of the jet, multi-frequency observations provide us with a virtual view of the structure of the jet on different scales. Radio--gamma-ray correlations, moreover, are essential to reveal where and how the high-energy radiation is produced. We present here the observations collected within the blazar radio monitoring program that we are running at the Medicina and Noto telescopes. It aims at investigating how the variability characteristics and spectral energy distribution of blazars evolve in time. Since 2004, observation have been performed at 5, 8, 24, and 43 GHz on 47 targets, with monthly cadence; the monitoring program is still active at frequencies of 8 and 24 GHz. The database we built in more than twenty years of activity comprises to date about 21000 flux density measurements. Some basic analysis tools have been applied to the data to characterise the detected variability and offer a first glance at the wealth of information that such a program can provide about blazars.

We combine near-infrared imaging in two bands from the Hubble Space Telescope (HST) with archival observations of molecular gas to study SDSS J160705.16+533558.6 (J1607), an extremely luminous broad-line quasar at $z = 3.65$ that is also bright in the submillimeter (sub-mm). Via subtraction of the quasar point spread function, we show that its host galaxy is massive, with a stellar mass of $(5.8 \pm 3.0) \times 10^{11}$ M$_{\odot}$, making it comparable to giant early-type galaxies (ETGs) at $z\sim0$. If the supermassive black hole (SMBH) in the quasar is accreting at the Eddington limit, then its mass is $3.5 \times 10^{9}$ M$_{\odot}$, which is also consistent with local massive ETGs. The host has an extremely high star formation rate (SFR) of $4300 \pm 500$\sfr and a molecular gas mass of $(2.4 \pm 0.9)\times 10^{10}$ M$_{\odot}$. The quasar has two companions: one at a projected separation of 11 kpc with a stellar mass of $(7.9 \pm 5.0) \times 10^{10}$ M$_{\odot}$ but no detected molecular gas, and one 6 kpc further away in the same direction with a molecular gas mass of $(2.6 \pm 1.3) \times 10^{10}$ M$_{\odot}$ but no detected stellar emission. Since neither companion shows evidence for AGN activity, this may represent merger-driven quenching, in which the dynamics of the merger strip molecular gas from infalling galaxies. Overall, irrespective of whether the host is merging with the companions, these properties mark J1607 as forming what will become an extremely massive ($\sim10^{12}M_{\odot}$) galaxy by $z=0$.

Photographic plates of the globular cluster M10 (NGC 6254) that were recorded at the Dominion Astrophysical Observatory between 1931 and 1934 have been digitized with a commercial scanner. The plates have numerous cosmetic issues, and the results are used to assess the information that can be extracted from such archival data. After performing a series of basic processing steps, a plate-to-plate dispersion in photometric measurements < 10% is delivered between V = 13 and 15. The light curves of known variables are constructed and evidence is presented for long term variations in the mean brightnesses of the W Vir star V3, as well as the semi-regular (SR) variable V29. Two new variable stars are identified, although cluster membership is possible for only one of these. A brightness-selected sample of candidate variable stars identified in the GAIA database that are not in the General Catalogue of Variable Stars is also examined, and some show variability in the plate photometry. Parallaxes indicate that five of the GAIA variables are at the same distance as M10. Four of the GAIA variables fall along the horizontal branch of M10 on the color-magnitude diagram. Another GAIA variable is located close to the cluster center, and may be evolving on the supra-horizontal branch. The plate photometry suggests that the Gaia variable with the most secure M10 membership based on parallax, proper motions, and velocity is an SR variable that is offset by a projected distance of 9 parsecs from the cluster center.

Stellar evolution theory predicts that electron--positron pair production in the cores of massive stars triggers unstable thermonuclear explosions that prevent the direct formation of black holes above about $50\,M_\odot$, creating a ``pair-instability gap''. Yet black holes have been detected above this mass with gravitational waves; such objects might be explained with uncertainties in the physics of massive stars and stellar collapse or with hierarchical mergers of black holes in stellar clusters. Hierarchical mergers are associated with large spins as predicted by general relativity, and isotropic spin orientations. Here we present strong evidence for the pair-instability mass gap in the LIGO--Virgo--KAGRA fourth transient catalog, with a lower edge at $45.3^{+6.5}_{-4.8}\,M_\odot$. We also obtain a measurement of the ${}^{12}\mathrm{C}(\alpha,\gamma){}^{16}\mathrm{O}$ reaction rate, yielding an $S$-factor of $242.5^{+310.4}_{-101.5}\,\mathrm{keV\,b}$, a parameter critical for modeling helium burning and stellar evolution. The new data reveal two populations: a low-spin group with no black holes above the gap, consistent with direct stellar collapse, and a high-spin, isotropic group that extends across the full mass range and occupies the gap, consistent with hierarchical mergers. These findings confirm the role of pair-instability in shaping the black hole spectrum, establish a new link between gravitational-wave astronomy and nuclear astrophysics, and highlight hierarchical mergers and star cluster dynamics as key channels in the growth of black holes.

As sites of some of the most efficient star formation in the Universe, globular clusters (GCs) have long been hypothesized to be the building blocks of young galaxies. Within the Milky Way, our best tracers of the contribution of GCs to the proto-Galaxy are stars with such anomalous overabundance in nitrogen and depletion in oxygen ("high-[N/O] stars") that they can be identified as having originated in a cluster long after they have escaped. We identify associations between these high-[N/O] field stars and GCs using integrals of motion and metallicities and compare to chemically typical halo stars to quantify any excess association, enabling a population-level exploration of the formation sites of the nitrogen-enhanced stars in the field. Relative to the halo as a whole, high-[N/O] stars show stronger associations with the most initially massive, inner Galaxy GCs, suggesting that many nitrogen-rich stars formed in these environments. However, when compared to a sample matched in orbital energy, the excess largely disappears: high-[N/O] stars are, on average, no more associated with surviving GCs than energy-matched halo stars, despite their [N/O] abundances indicating GC origins, consistent with a scenario in which a substantial fraction of low-energy inner-halo stars originate in GCs, so an energy-matched control dilutes any differential excess. We argue that associations between high-[N/O] stars and their parent GCs are further weakened because dynamical friction and the Galactic bar have altered integrals of motion, limiting the reliability of precise present-day associations and, especially, individual star-to-cluster tagging.

We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) and Mid-infrared Instrument (MIRI) integral-field spectroscopy of the nearby blue compact dwarf II Zw 40, which has a low metallicity of 25% of solar. Leveraging the high spatial/spectral resolution and wavelength coverage of JWST/NIRSpec, we present robust detections of the 3.3 um polycyclic aromatic hydrocarbon (PAH) emission on 20 pc scales. The strength of the Pf delta emission relative to the 3.3 PAH feature is significantly stronger than typical higher metallicity star-forming galaxies. We find that 3.3 um PAH emission is concentrated near the northern super star cluster and is co-spatial with CO gas. A strong correlation exists between the 3.3/11.3 PAH ratio and radiation hardness probed by NeIII/NeII, providing evidence of photodestruction of PAH molecules in intense radiation environments. Our analysis shows that while the overall PAH fraction is lower in II Zw 40 than in higher metallicity galaxies, the contribution of the 3.3 um PAH feature to the total PAH emission is higher. We propose that the PAH size distribution is fundamentally shaped by two competing mechanisms in low-metallicity environments: photo-destruction and inhibited growth. Additionally, the high radiation field intensity in II Zw 40 suggests that multi-photon heating of PAHs may be an important effect. As one of the first spatially resolved studies of aromatic emission in a low-metallicity environment, our spectroscopic results offer practical guidance for future observations of the 3.3 um PAH feature in low-metallicity galaxies using JWST.

A coronal hole formed as a result of a quiet-Sun filament eruption close to the solar disk center on 2014 June 25. We studied this formation using images from the Atmospheric Imaging Assembly (AIA), magnetograms from the Helioseismic and Magnetic Imager (HMI), and a differential emission measure (DEM) analysis derived from the AIA images. The coronal hole developed in three stages: (1) formation, (2) migration, and (3) stabilization. In the formation phase, the emission measure (EM) and temperature started to decrease six hours before the filament erupted. Then, the filament erupted and a large coronal dimming formed over the following three hours. Subsequently, in a phase lasting $15.5$~hours, the coronal dimming migrated by 150" from its formation site to a location where potential field source surface extrapolations indicate the presence of open magnetic field lines, marking the transition into a coronal hole. During this migration, the coronal hole drifted across quasi-stationary magnetic elements in the photosphere, implying the occurrence of magnetic interchange reconnection at the boundaries of the coronal hole. In the stabilization phase, the magnetic properties and area of the coronal hole became constant. The EM of the coronal hole decreased, which we interpret as a reduction in plasma density due to the onset of plasma outflow into interplanetary space. As the coronal hole rotated towards the solar limb, it merged with a nearby pre-existing coronal hole. At the next solar rotation, the coronal hole was still apparent, indicating a lifetime of >1 solar rotation.

Kete is an open-source software package for quickly and accurately predicting the positions and magnitudes of asteroids and comets in large-scale, all-sky surveys. It can predict observable objects for any ground or space-based telescope. Kete contains a collection of tools, including simple optical and thermal modeling, $n$-body orbit calculations, and custom multi-threaded SPICE kernel support. It can be used for observation planning, pre-discovery of detections at a large scale, and labeling known solar system objects in images. Here we demonstrate some of the capabilities by predicting all observations of every numbered asteroid seen by the Wide-field Infrared Survey Explorer (WISE) and Zwicky Transient Facility (ZTF) surveys during single years of their operations, predicting locations and magnitudes of 756,999 asteroids in over 11 million images.

Clusters of galaxies are unique laboratories for investigating the dependence of galaxy evolution on their environment. The Herschel Virgo Cluster Survey (HeViCS) mapped the central 84 square degrees region of the Virgo Cluster in five bands between 100 and 500 micron, which resulted in the first detailed view of cold dust in cluster galaxies. Major limitations of the HeViCS survey were the lack of data, or its limited availability, in the 20 to 80 micron range, and the quite low sensitivity of the Photodetector Array Camera and Spectrometer instrument, resulting in poor constraints on the warmer dust component. The PRIMAger instrument onboard PRIMA offers the capability to map a large portion of the Virgo Cluster -- including regions beyond its virial radius -- in hyperspectral and polarimetric bands from 25 to 265 micron, enabling a direct comparison with the area previously covered by HeViCS. By combining PRIMA and Herschel data with existing multi-wavelength photometry, it becomes possible to explore the connection between stellar and dust properties in a complete sample of cluster galaxies, to investigate environmental effects on the warm dust component within the Virgo Cluster, to map the magnetic field structure of the cold interstellar medium (ISM), to search for dust emission from the intra-cluster medium, and to study the ISM in background galaxies projected behind the cluster.

Angular momentum transport in high-mass stars is commonly modeled by extrapolating the behavior of better-observed low-mass stars. According to the conventional picture, the cores of most black hole progenitors lose almost all of their angular momentum when their outer layers are ejected before core collapse. Accordingly, most black holes are expected to be born with dimensionless spin magnitudes of $\chi \lesssim 0.01$, even if some black holes are born with non-negligible spin due to tidal interactions in a progenitor binary. One might therefore expect to find a large fraction of $\chi \lesssim 0.01$ black holes in merging binary black hole (BBH) systems. We find that the conventional picture of angular momentum transport is in tension with data from LIGO--Virgo--KAGRA's fourth gravitational-wave transient catalog. We find no support for a sub-population of BBH systems with $\chi \lesssim 0.01$. Neither do we find support for a sub-population with only one spinning black hole as expected for tidal spin-up scenarios. Instead, we find evidence for two subpopulations in which both black holes have non-negligible spin. Approximately 84% of BBH systems contain two black holes with modest spins $\chi \approx 0.1$ and approximately 16% contain two black holes with large spins $\chi \approx 0.8$. These estimates come from our best-fit model, which is favored with natural log Bayes factors $\ln B \gtrsim 3$ over models that require a sub-population of $\chi \lesssim 0.01$ black holes, and models that do not contain multiple spin sub-populations. These results are difficult to reconcile with our current understanding of angular momentum transport.

We present ultraviolet, optical, and infrared observations of the Type II-P supernova SN 2022acko in NGC 1300, located at a distance of 19.0 +/- 2.9 Mpc. Our dataset spans 1-350 days post-explosion in photometry, complemented by late-time optical spectroscopy covering 200-600 days, and includes deep pre-explosion imaging. We use this extensive multiwavelength dataset for both direct and indirect constraints on the progenitor system. Using the early-time photometry and shock-cooling models, we infer that SN 2022acko likely originated from a red supergiant with a radius of R ~ 580 solar radii and an initial mass of M ~ 9-10 solar masses. From the radioactive decay tail, we infer a synthesized Ni56 mass of 0.014 +/- 0.004 solar masses. We further model nebular-phase spectra using radiative transfer models and nucleosynthesis yields for core-collapse supernovae, which suggest a progenitor initial mass in the range of 10-15 solar masses. Meanwhile, blackbody fitting of the detected pre-explosion counterpart in the F814W and F160W bands indicates a red supergiant with a lower initial mass of approximately 7.5 solar masses. The light curve exhibits a 116 days plateau, indicative of a massive hydrogen-rich envelope, inconsistent with the pre-explosion analysis. We investigated the discrepancy between direct and indirect progenitor mass estimates, focusing on the roles of binary interaction, early-time modeling limitations, and systematic uncertainties in spectral calibration. Our results indicate that the tension among mass estimates likely arises from modeling limitations and flux calibration uncertainties rather than from insufficient data, highlighting the need for more physically realistic models and a deeper understanding of systematic effects.

I examine recent radio observations of the supernova remnant (SNR) RCW 89 and identify a point-symmetric morphology composed of two main symmetry axes. I attribute this morphology to a jet-driven explosion in the framework of the jittering jets explosion mechanism (JJEM). To reach this conclusion, I argue that the MSH 15-52 nebula associated with the pulsar PSR B1509-58, the X-ray hand-like-shaped nebula, and RCW 89 are two separate core-collapse supernova (CCSN) remnants that interact with each other. Namely, the nebula SNR G320.4-1.2 contains two CCSN remnants. In essence, I utilize the recent successes of the JJEM to account for the morphologies of point-symmetric CCSN remnants, thereby explaining the morphology of RCW 89 and identifying it as a separate CCSN remnant. I suggest a process by which somewhat more energetic pairs of jets in the JJEM have a positive feedback on the accreted gas onto the newly born neutron star, thereby prolonging the life of the jets and explaining the occurrence of two or three energetic pairs of jets in some CCSNe. This study adds RCW 89 to the growing list of point-symmetric CCSN remnants. The JJEM naturally explains these morphologies as shaped by misaligned pairs of jets that exploded these CCSNe.

Solar jets are collimated plasma ejections driven by magnetic reconnection, which play a critical role in the energy release and mass transport in the solar atmosphere. Using Solar Orbiter's Extreme Ultraviolet Imager (EUI) with its unprecedented spatiotemporal resolution, we report the discovery of nine transient coronal jets associated with a filament eruption on September 30, 2024. These jets, with a median lifetime of only 22 seconds, have significantly shorter timescales than previously observed coronal jets. They exhibit diverse morphologies and properties, evolving through three distinct phases of the filament eruption: initiation, rise, and peak. The spatial and temporal distribution of the jets suggests they are driven by dynamic magnetic reconnection between the erupting filament and overlying magnetic fields. These jets represent a distinct class of phenomena different from traditional mini-filament-driven jets, being directly associated with large-scale filament eruption processes. This study reveals a previously unrecognised class of highly transient jets, highlighting the complexity of reconnection-driven processes during filament eruptions and underscoring the importance of high-resolution observations in uncovering fundamental plasma dynamics in the solar atmosphere.

Solar filament eruptions play a key role in driving space weather, yet their fine-scale evolution remains poorly understood due to observational limitations. Using unprecedented high-resolution observations from Solar Orbiter's Extreme Ultraviolet Imager (105 km/pixel) and Polarimetric and Helioseismic Imager, we reveal persistent magnetic reconnection events in a failed filament eruption. We identify magnetic reconnections between the filament and surrounding magnetic field structures, with both frequency and type far exceeding previous observations. These reconnections significantly affect the filament stability and eruption dynamics, leading to sequential coronal jets and failed eruptions. We propose a 'persistent magnetic cutting' concept, highlighting how persistent small-scale magnetic reconnections cumulatively affect filament stability during its evolution.

The rapid expansion of exoplanet survey missions such as Kepler, TESS, and the upcoming PLATO mission has generated massive light-curve datasets that challenge traditional vetting pipelines. We introduce a hybrid deep-learning framework that integrates convolutional networks, bidirectional LSTMs, and an attention mechanism to identify planetary transit signals with improved accuracy and interpretability. Trained on Kepler DR25 data, the model achieves F1 = $0.910 \pm 0.008$ (AUC--ROC = $0.984 \pm 0.004$), significantly outperforming CNN-only baselines. Attention-based visualizations highlight ingress and egress phases consistent with astrophysical expectations. Applied to 1,360 DR25 candidate dispositions, our pipeline identified 190 high-confidence signals (P(model) $<$ 0.70) that passed initial validation. Following comprehensive false positive probability (FPP) analysis and contamination tests, 13 candidates achieved statistical validation, of which three were fully confirmed as robust exoplanets: KOI-901.01 (warm mini-Neptune), KOI-1066.01 (hot Jupiter), and KOI-212.01 (warm Neptune). With an inference time of $\sim 80$ ms per candidate, this framework enables scalable real-time triage for TESS and future PLATO operations, while the validated candidates provide a prioritized list for radial velocity, timing, and atmospheric follow-up. This interpretable, efficient pipeline addresses the bottleneck in exoplanet confirmation, advancing scalable discovery in the era of large-scale surveys.

Turbulence influences the structure and dynamics of molecular clouds, and plays a key role in regulating star formation. We therefore need methods to accurately infer turbulence properties of molecular clouds from position-position-velocity (PPV) spectral observations. A previous method calibrated with simulation data exists to recover the 3D turbulent velocity dispersion from PPV data. However, that method relies on optically-thin conditions, ignoring any radiative transfer (RT) and chemical effects. In the present study we determine how opacity, RT, and chemical effects influence turbulence measurements with CO lines. We post-process a chemo-dynamical simulation of a turbulent collapsing cloud with a non-local thermodynamic equilibrium line RT code to generate PPV spectral cubes of the CO (1-0) and CO (2-1) lines, and obtain moment maps. We isolate the turbulence in the first-moment maps by using a Gaussian smoothing approach. We compare the CO results with the optically-thin scenario to explore how line excitation and RT impact the turbulence measurements. We find that the turbulent velocity dispersion (sigma_v) measured via CO requires a correction by a factor R_CO, with R_CO,1-0 = 0.88 (+0.09, -0.08) for the CO (1-0) line and R_CO,2-1 = 0.88 (+0.10, -0.08) for the CO (2-1) line. As a consequence, previous measurements of sigma_v were overestimated by about 10-15% on average, with potential overestimates as high as 40%, taking the 1-sigma uncertainty into account.

We investigate the impact of dark matter (DM) on both hybrid and twin stars within a two-fluid framework, where DM and normal matter interact only through gravity. A self-interacting fermionic DM model is considered, while for nucleonic and quark matter we employ the relativistic mean-field model and the constant sound-speed parametrization, respectively. Our results show that DM significantly influences the formation of hybrid and twin stars, depending on the transition pressure and the discontinuity in energy density at a fixed sound speed. The presence of DM reduces the number of twin or hybrid stars compared to the case without DM, and this effect directly depends on the DM mass and fraction. We further find that the formation of DM-core or DM-halo configurations is mainly governed by DM parameters, whereas the realization of twin or hybrid star scenarios is primarily controlled by quark parameters. Using the $2M_\odot$ constraint, we demonstrate that the parameter space for twin stars can be further restricted in both DM-core and DM-halo scenarios.

The work aims to assess principal physical technical constraints of the key technological concept for achieving maximal carrying capacity expansive potential of Planetary Systems. Chemical composition of most potential Biosphere Substrates is in most cases very far from optimal for full-scale habitability thus productivity potential realization. To cover all surface of a Biosphere Substrate with a dense photosynthesising layer during most of remaining Planetary System lifecycle for achieving maximal carrying capacity thus workforce productivity enabling further expansion of biosphere to new substrates importing significant amounts of the limiting chemical elements by planetesimals redirection is ubiquitously inevitable. Although the price of such operations is high the value of maximal population productivity of Biosphere Substrates during the remaining Planetary Systems lifecycle is orders of magnitude higher. The farther planetesimal is orbiting from a star the more time but less energy is required for its delivery. The more distant from a star, the more rich in volatiles planetesimals are. The most technically detailed and feasible scheme to date of Planetesimals Redirection was proposed in 1993 by Dr. Zubrin based on NTRs. Nuclear fuel is extremely scarce and might be the principal limiting factor for final stages of interstellar colonization missions. We investigate possibilities of using concentrated beamed solar power Planetesimals Redirection operations for Terraforming as it can increase the possible scale of such operations to orders of magnitude. Such a mission might consist of Planetesimal Tug Spacecraft Systems (PTSS) to redirect a planetesimal, and solar Power Harvesting Beaming System (PHBS) tracking the spacecraft with a beam to power it. We found Solarpowered Planetesimals Redirection for Terraforming is feasible within Kuiper Belt with present technologies.

The term Biosphere Substrate is introduced for celestial bodies, like terrestrial planets or big gas giant moons, suitable to sustain full-scale open biosphere after Terraforming. The purpose of the work is to examine the range of parameters for a biosphere substrate. Most importantly, Biosphere Substrate gravity should sustain full-scale open breathable atmosphere dense enough after Terraforming during the lifecycle of Planetary System. Humans can not reproduce in too low gravity, can not restore functionality after long exposure to microgravity. Extremely high gravity is also the limit for complex life forms functioning. Gravity is the main parameter that is the most difficult to change, thus the range of celestial object sizes fitting the Biosphere Substrate definition is examined first. The capability of a celestial body to retain breathable atmosphere during Planetary System lifecycle depends on planetary magnetic field strength, thus plate tectonics is necessary, sufficient satellite is needed for geodynamo. As chemical composition of Biosphere Substrate surface hydrosphere atmosphere can be drastically adjusted in most cases by importing planetesimas material, this factor in most cases does not determine whether a celestial body can become a Biosphere Substrate. But for water worlds where any solid material to build biological bodies and industrial structures can be more than thousand kilometers deep, chemical composition can become an issue. Temperature is another important parameter, as complex life can exist in rather narrow range. For a full-scale open biosphere development, there must be a sufficient source of power. A Biosphere Substrate orbit must be within technically extendable circumstellar habitable zone. For planets with solid crusts, their rotation thus daylength & tilt can be adjusted by hitting asteroids and comets strictly tangentially with high velocities.

To date, quantification of the on-sky motion for interstellar clouds have relied on proxies such as young stellar objects (YSO) and masers. We present the first direct measurement of an interstellar cloud proper motion using the VISTA Star Formation Atlas (VISIONS) multi-epoch infrared images of the Corona Australis star-forming region. Proper motions are extracted by tracking the morphology of extended structures in the cloud complex based on image registration techniques implemented in SimpleITK. Our determined values ($\mu_{\alpha^*} \sim +15$ mas/yr, $\mu_{\delta} \sim -30$ mas/yr) are in good agreement with those obtained for YSOs and young stellar clusters in the region. This study demonstrates the potential of image registration for directly mapping the kinematics of nearby molecular clouds, opening a new window into the study of cloud dynamics.

Infrared Dark Clouds (IRDCs) are cold, dense structures representative of the initial conditions of star formation. Many studies of IRDCs employ CO to investigate cloud dynamics. However, CO can be highly depleted from the gas phase in IRDCs, impacting its fidelity as tracer. CO depletion is also of great interest in astrochemistry, since CO ice in dust grain mantles provides the raw material for forming complex organic molecules. We study CO depletion toward four IRDCs to investigate how it correlates with volume density and dust temperature, calculated from Herschel images. We use 13CO(1-0) and (2-1) maps to measure CO depletion factor, $f_D$, across IRDCs G23.46-00.53, G24.49-00.70, G24.94-00.15, and G25.16-00.28. We also consider a normalized CO depletion factor, f_D', which takes a value of unity, i.e., no depletion, in the outer, lower density, warmer regions. We then investigate the dependence of f_D and f_D' on gas density, $n_H$ and dust temperature, $T_{dust}$. We find CO depletion rises as density increases, reaching maximum values of f_D'$\sim$10 in regions with $n_H>3\times10^5\:{cm}^{-3}$, although with significant scatter at a given density. We find a tighter, less scattered relation of f_D' with temperature, rising rapidly for temperatures <18 K. We propose a functional form $f_D^\prime = \:{exp}(T_0/[T_{dust}-T_1])$ with $T_0\simeq4\:$K and $T_1\simeq12\:$K to reproduce this behaviour. We conclude that CO is heavily depleted from the gas phase in cold, dense regions of IRDCs. Thus CO depletion can lead to underestimation of total cloud masses based on CO line fluxes by factors up to 5. These results indicate a dominant role for thermal desorption in setting near equilibrium abundances of gas phase CO in IRDCs, providing important constraints for both astrochemical models and the chemodynamical history of gas during the early stages of star formation.

In this work, we present an off-lattice Monte Carlo model of accretion and migration of hydrogen atoms on a rough surface of carbon dust grain. The migration of physisorbed atoms by means of thermal diffusion and quantum tunnelling through barriers between the surface potential minima is considered. The model is applied to simulations of molecular hydrogen formation in a cold interstellar medium for a temperature range 5-35 K. Eley-Rideal and Langmuir-Hinshelwood mechanisms for the formation of the H$_2$ molecule were taken into account. We found that the surface potential energy minima that hold the accreted hydrogen atoms (binding energy) has wide dispersion of its values. The minimum energy is three times smaller than the maximum energy for the uneven surface of the model grain. The large dispersion of the binding energies results in an extended range of temperatures where H$_2$ formation is efficient: 5-25 K. The dispersion of binding energies also reduces efficiency of diffusion due to tunnelling in comparison to that assumed in kinetic equation codes in which constant values of binding energies are employed. Thus, thermal hopping is the main source for the mobility of the hydrogen atoms in the presented off-lattice model. Finally, the model naturally provides the mean values for the ratio of binding-to-desorption energy. This ratio demonstrates weak dependence on temperature and is in the range of 0.5-0.6.

The diffuse interstellar band (DIB) at 6196 A exhibits notable profile variations across the Milky Way. This study addresses three open issues: the unusual broadening of the DIB profile towards Upper Sco (USco), the lack of profile variations towards stars near $\eta$ Car, and the origin of the blueshift observed in Sco OB1. Using archival spectra of 453 early-type stars across the Galactic disk and in its proximity, we created a catalogue of the DIB's profile parameters. Our analysis identified Doppler-split components within the DIB profiles across most regions with no evidence for these splits being able to account for the observed broadening (23 km/s) in USco or other regions such as Orion, Vela OB2, and Melotte 20 ($\alpha$ Per cluster). We propose that neither the ages of the studied stellar populations nor the distances between clusters and nearby clouds significantly contribute to the broadening. However, we detect a gradient in the full width at half maximum within the Sco-Cen and Orion regions, where broadening decreases with distance from the star-forming centres. This result points to a possible connection between the DIB broadening and star formation (likely via the impact of recent supernovae). Regarding the Carina Nebula, we confirm the lack of DIB profile variations in a small region near $\eta$ Car, although an adjacent southern area exhibits significant variations, comparable to those in USco. In addition to the Carina Nebula, we find that the Rosette Nebula and NGC 6405 also show consistently narrow profiles (<20 km/s) with minimal deviations from the median over spatial scales of a few parsecs. Finally, regarding the origin of the blueshift observed in Sco OB1, we used a comparison with the Lagoon Nebula and argue that the most natural explanation is the presence of an unresolved kinematic component in the profile of the DIB, shifting the measured centre of the band.

The CarbON [CII] line in post-rEionisation and ReionisaTiOn epoch (CONCERTO) instrument is a low-resolution mapping Fourier-transform spectrometer, based on lumped-element kinetic inductance detector (LEKID) technology, operating at 130- 310 GHz. It was installed on the 12-meter APEX telescope in Chile in April 2021 and operated until December 2022. CONCERTO's main science goal is to constrain the [CII] line fluctuations at high redshift. To reach that goal CONCERTO observed 1.4 deg2 in the COSMOS field. To ensure accurate calibration of the data, we have developed a forward model capable of simulating both the spectral response and the corresponding interferograms for each scan of observation in the COSMOS field. We present the modeling approach that enables us to reproduce the expected instrument outputs under controlled input conditions and provides a framework for the different calibration steps, including the absolute brightness calibration of the spectra. We constructed a dedicated analysis pipeline to characterize the raw interferometric data (interferograms) obtained under a broad range of atmospheric conditions at APEX. Using the forward model, we measured the interferogram alignment with the optical path difference (zero path difference, ZPD) and the relative response of each KID (flatfield). Together, these elements enable a robust characterization of the instrument's spectral brightness calibration.

Young ($\lesssim 10$ Myr) planetary-mass companions (PMCs) provide valuable insights into the formation and early evolution of planetary systems. To date, only a dozen such objects have been identified through direct imaging. Using JWST/NIRCam observations towards the Orion Nebula, obtained as part of the \textit{PDRs4All} Early Release Science program, we have identified a faint point source near the M-type star V2376 Ori. Follow-up spectroscopic observations with the MUSE instrument on the VLT confirm that the source, V2376 Ori b, is indeed a young planetary-mass companion. It is a member of Orion D, around 80\,pc in the foreground of the Trapezium cluster of Orion and with an age of approximately $7 \pm 3$ Myr. We fit the SED of V2376 Ori b to infer a mass of $ \sim 20~M_{\rm Jup}$. The MUSE spectrum reveals several accretion tracers. Based on the H$\alpha$ line intensity, we estimate an accretion rate of $\sim$10$^{-6.5 \pm 0.7}~\rm M_{Jup}\,yr^{-1}$, which is comparable to that of young PMCs such as PDS~70b. In addition, the MUSE data cube reveals extended emission in the [O\,\textsc{ii}] doublet at 7320 and 7330~Å, which is interpreted as evidence of a dynamical interaction between the two sources that, potentially, involves mass transfer between their individual accretion disks. These results demonstrate that JWST/NIRCam imaging surveys of young stellar associations can uncover new PMCs, which can then be confirmed and characterized through ground-based spectroscopic follow-up.

By analysing the radio emissions from air showers using interferometry, we can estimate their properties. In this contribution, we apply interferometry to reconstruct air-shower parameters based on measurements taken with the Auger Engineering Radio Array (AERA) at the Pierre Auger Observatory. This reconstruction method is achievable at AERA through precise clock synchronisation with a beacon and an accurate survey of the station locations. Interferometry has been applied to several thousand inclined air-shower observations for the first time, which allows for tests on the performance of air-shower geometry reconstruction, recovery of the radio signal from low-energy air showers, and methods to study the polarisation of the radio-emission mechanisms. Additionally, in this contribution, we will also provide an overview of efforts to enable interferometry for the recently installed radio detectors that are part of the AugerPrime upgrade.

New observations with the current generation of advanced radio interferometers, such as ASKAP and MeerKAT, have led to the discovery of new classes of extended radio sources of unknown origin, including the so-called Odd Radio Circles (ORCs). These phenomena are detected exclusively in the radio continuum, with no clear counterparts at other wavelengths, making their physical nature and origin a subject of ongoing investigation. To better understand these objects, we study their radio continuum emission, spectral characteristics, and magnetic field properties. In this work, we present a radio spectropolarimetry analysis of a newly discovered ORC (ORC J0356-4216) that exhibits a rare double-ring morphology. We use data from the MeerKAT L-band and from the ASKAP Evolutionary Map of the Universe (EMU) at 943 MHz. ORC J0356-4216 shows a symmetric double-ring structure with a diameter of approximately 2 arcminutes, corresponding to a physical size of 668 kpc based on the redshift ($0.494 \pm 0.068$) of its apparent host galaxy WISEA J035609.67-421603.5. The radio spectra of both rings are steep, with spectral indices of $-1.18 \pm 0.03$ and $-1.12 \pm 0.05$, and show no significant substructure. Equipartition magnetic field strengths (assuming K0 = 1) are estimated to be 1.82 microGauss and 1.65 microGauss for the respective rings. The degree of polarisation across the object ranges between 20-30%, consistent with a non-thermal synchrotron origin. The morphology and polarisation are broadly consistent with large-scale shocks driven by powerful starburst outflows. However, the high degree of symmetry, the coherent double-ring structure, and the absence of internal substructure are features commonly associated with relic AGN lobes, making this scenario particularly compatible with the observed characteristics.

Post-asymptotic giant branch (post-AGB) stars are exquisite tracers of s-process nucleosynthesis via their surface abundances. We present a comprehensive analysis of J003643.94$-$723722.1 (J003643), a single SMC post-AGB star, using high-resolution UVES/VLT spectra analysed with E-iSpec. We find C/O = 16.21 and $[\mathrm{s}/\mathrm{Fe}]=2.09\pm0.20 \mathrm{dex}$. We also report the first direct Pb detection in a post-AGB star from the Pb II 5608.853 A line, with $[\mathrm{Pb}/\mathrm{Fe}]=3.18\,\mathrm{dex}$. Comparison with post-AGB samples in the Galaxy and Magellanic Clouds reveals that J003643 has an unusually high C/O ratio. J003643's $[\mathrm{C}/\mathrm{Fe}]=1.33\pm0.14 \mathrm{dex}$ and $[\mathrm{s}/\mathrm{Fe}]=2.09\pm0.20\,\mathrm{dex}$ are consistent with third dredge-up enrichment, but its $[\mathrm{O}/\mathrm{Fe}]=-0.08\pm0.20\,\mathrm{dex}$ is low relative to objects of similar $[\mathrm{C}/\mathrm{Fe}]$ and $[\mathrm{Fe}/\mathrm{H}]$. Together with $[\alpha/\mathrm{Fe}]\approx0\,\mathrm{dex}$ at $[\mathrm{Fe}/\mathrm{H}]\approx-1\,\mathrm{dex}$, consistent with SMC chemical evolution, this indicates the high C/O chiefly reflects oxygen deficiency rather than exceptional carbon enrichment. Additionally, we compare the full abundance pattern with yields from ATON, MONASH and FRUITY (the latter two with post-processing nucleosynthesis). Most elements are reproduced, but Pb is strongly underpredicted, highlighting a persistent gap in models of heavy-element production in AGB stars. The photospheric chemistry of J003643 adds to the growing diversity among post-AGB stars and underscores the complexity of AGB nucleosynthesis.

The X-ray Imaging and Spectroscopy Mission (XRISM), launched into low-Earth orbit in 2023, observes the reflection of solar flare X-rays in the Earth's atmosphere as a by-product of celestial observations. Using a $\sim$one-year data set covering from October 2023 to November 2024, we report on our first results of the measurement of the metal abundance pattern and high-resolution Fe-K spectroscopy. The abundances of Mg, Si, S, Ar, Ca, and Fe measured with the CCD detector Xtend during M- and X-class flares show the inverse-first-ionization-potential (inverse-FIP) effect, which is consistent with the results of Katsuda et al., ApJ, 2020 using the Suzaku satellite. The abundances of Si, S, and Ar are found to decrease with increasing flare magnitude, which is consistent with the theoretical model by Laming (Laming, ApJ, 2021), whereas Ca exhibits an opposite trend. The large effective area and field of view of Xtend allow us to trace the evolution of the abundances in several X-class flare loops on a timescale of a few 100 s, finding an enrichment of low-FIP elements before flare peaks. The high-resolution Fe-K spectrum obtained with the microcalorimeter Resolve successfully separates the Rayleigh- and Compton-scattered Fe XXIV/XXV lines and neutral or low-ionized Fe-K$\alpha$ lines. The neutral/low-ionized Fe-K$\alpha$ equivalent width shows an anti-correlation with hard X-ray flux with the best-fit power-law slope of $-0.14 \pm 0.09$, suggesting that hard X-rays from flare loops are stimulating the Fe K$\alpha$ fluorescence. This work demonstrates that XRISM can be a powerful tool in the field of solar physics, offering valuable high-statistic CCD data and high-resolution microcalorimeter spectra in the energy range extending to the Fe-K band.

Conductive cooling of the solar corona at a magnetic null is examined. An initial equilibrium is set up, balancing thermal conduction and a constant, spatially uniform coronal heating. The heating is then turned off and the subsequent conductive cooling calculated. An equation for the cooling is obtained using the method of separation of variables and it is shown that the equations for the equilibrium between conduction and heating, and the time-dependent cooling are mathematically identical with a simple change of variables. Thus the properties of the cooling phase are automatically determined by the equilibrium state. For a two-dimensional null, the characteristic cooling timescale increases over that in a straight field by a factor of between 2 and 5, with a scaling determined by the ratio of the {\it{average}} and base areas of a flux element. There is {\it{no explicit dependence}} on the very large areas that can arise near the null.

We present the discovery by the TESS mission of one transiting Neptune-sized planet, TOI-6223 b and two transiting super-Earths, TOI-1743 b and TOI-5799 b. We validate these planets using a statistical validation method, multi-color light curves and other ancillary observations. We combined TESS and ground-based photometric data to constrain the physical properties of the planets. TOI-6223-b is slightly larger than Neptune ($R_p=5.12^{+0.24}_{-0.25}$ $R_\oplus$) orbiting an early M dwarf in 3.86 days, and it has an equilibrium temperature of $T_{\rm eq}=714\pm14$ K. TOI-1743 b orbits its M4V star every 4.27 days. It has a radius of $R_p=1.83^{+0.11}_{-0.10}$ $R_\oplus$ and an equilibrium temperature of $T_{\rm eq}=485^{+14}_{-13}$ K. TOI-5799 b has a radius of $R_p=1.733^{+0.096}_{-0.090}$ $R_\oplus$, and an equilibrium temperature of $T_{\rm eq}=505\pm16$ K orbits an M2 dwarf in 4.17 days. We also present the discovery of an additional transiting planet, TOI-5799 c, that we identified in the TESS data and validated using the SHERLOCK pipeline. TOI-5799 c is a super-Earth with a radius of $R_p=1.76^{+0.11}_{-0.10}$ $R_\oplus$. Its orbital period and its equilibrium temperature are 14.01 days and $T_{\rm eq}=337\pm11$ K, which place it near the inner edge of the habitable zone of its this http URL show that these planets are suitable for both radial velocity follow-up and atmospheric characterization. They orbit bright (< 11 $K_{mag}$) early M dwarfs, making them accessible for precise mass measurements. The combination of the planet sizes and stellar brightness of their host stars also make them suitable targets for atmospheric exploration with the JWST. Such studies may provide insights into planet formation and evolution, as TOI-1743-b, TOI-5799-b, and TOI-5799-c lie within the so-called radius valley, while TOI-6223-b is located on the Neptunian ridge in the period-radius plane.

From 2002 to 2025, the Hubble Space Telescope's Advanced Camera for Surveys has suffered in the harsh radiation environment above the protection of the Earth's atmosphere. We track the degradation of its image quality, as Solar protons and galactic cosmic rays have damaged its photosensitive charge-coupled device (CCD) imaging sensors. The damage is consistent with defects in the silicon lattice that have all annealed into one of three configurations. The rate of damage in low Earth orbit is modulated by $18.5^{+4.5}_{-0.5}$ per cent during an 11 year Solar cycle, peaking $430^{+11}_{-5}$ days after Solar minimum as recorded in the number of sunspots. We also present the open-source Algorithm for Charge Transfer Inefficiency correction (ArCTIc) v7. This models the (instantaneous or gradual) capture of photoelectrons into lattice defects, and their release after (a discrete set or continuum of) characteristic time delays, which creates spurious trailing in an image. Calibrated using the trailing of hot pixels, and applied during post-processing of astronomical images, ArCTIc can correct 99.5% of Charge Transfer Inefficiency trailing averaged over the camera's lifetime, and 99.9% of trailing in the worst-affected recent data.

We report on the first moderate-length time-scale observations of a young stellar object (YSO) at microwave frequencies. V830 Tau was monitored over the course of eight days with the JVLA at a frequency range of 4-8 GHz. Previous brief radio observations of this purported planet-hosting star indicated a radio-bright source with sparse evidence of dramatic intensity changes. Our observations confirm variability larger than a factor of five over the 8 days, with closer-spaced data indicating a long-lived flare event spanning multiple days. We discuss a hypothesis that the large, long-duration radio flare may be produced as a result of magnetospheric interaction between the star and its purported planet, using multi-year monitoring of a few active binary systems with the Green Bank Interferometer to augment our discussion. Although we cannot disentangle the effect of the large stellar surface area from any effects of orbital separation, the disputed star-planet system would have a large amount of power generated from stretching and breaking of magnetic fields. If this long-duration flare behavior repeats with additional data on timescales close to the planetary orbital period, microwave signatures of interacting magnetospheres could be a new observational tool to confirm the existence of planets around young, magnetically active stars.

The 21 cm signal arising from fluctuations in the neutral hydrogen field, and its cross-correlation with other tracers of cosmic density, are promising probes of the high-redshift Universe. In this study, we assess the potential of the 21 cm power spectrum, along with its cross power spectrum with dark matter density and associated bias, to constrain both astrophysics during the reionization era and the underlying cosmology. Our methodology involves emulating these estimators using an Artificial Neural Network (ANN), enabling efficient exploration of the parameter space. Utilizing a photon-conserving semi-numerical reionization model, we construct emulators at a fixed redshift ($z = 7.0$) for $k$-modes relevant to upcoming telescopes such as SKA-Low. We generate $\sim7000$ training samples by varying both cosmological and astrophysical parameters along with initial conditions, achieving high accuracy when compared to true simulation outputs. While forecasting, the model involves five free parameters: three cosmological ($\Omega_m$, $h$, $\sigma_8$) and two astrophysical (ionizing efficiency, $\zeta$, and minimum halo mass, $M_{\mathrm{min}}$). Using a fiducial model at the mid-reionization stage, we create a mock dataset and perform forecasting with the trained emulators. Assuming a 5% observational uncertainty combined with emulator error, we find that the 21 cm and 21 cm-density cross power spectra can constrain the Hubble parameter ($h$) to better than 6% at a confidence interval of 95%, with tight constraints on the global neutral fraction ($Q_{\mathrm{HI}}$). The inclusion of bias information further improves constraints on $\sigma_8$ (< 10% at 95% confidence). Finally, robustness tests with two alternate ionization states and a variant with higher observational uncertainty show that the ionization fractions are still reliably recovered, even when cosmological constraints weaken.

T CrB is a nearby symbiotic binary and a recurrent nova with a period of ca. 80 years. The next eruption is expected to take place in 2025 or 2026. We present our pre-eruption observations made in ALMA frequency Bands 1, 3, 4, 6, 7, and 8 in August to November 2024 and constrain the properties of the environment into which the imminent next nova will erupt. We find that in the second half of 2024, the quiescent T CrB was a faint mm source with a spectral energy distribution well described by a powerlaw with index $\alpha=$0.56$\pm$0.11 and a flux density of ca. 0.1 mJy at 44 GHz and 0.4 mJy at 400 GHz. There is no significant line emission. This is in agreement with expectations for free-free emission from the partially ionized wind of the red giant donor star and, in extrapolation to 35 GHz, a factor 5 fainter than the emission observed in 2016/17 during the latest high state. Comparing the spectra from that high-state between 13.5 GHz and 35 GHz with our spectrum from 2024, our spectrum is softer. The spectral index is on average lower by 0.34$\pm$0.11 . Our per-band and aggregate bandwidth images of T CrB show an unresolved point source with no evidence for extended structure. A simple model of a free-free emitting, fully-ionized stellar wind seems to describe well the 2016/17 high state of T CrB but not our 2024 ALMA measurements with their low flux and high turnover frequency suggesting that in 2024, the wind was far from fully ionized. (See the unabridged version of the abstract in the paper.)

The Pierre Auger Observatory is the largest air-shower detector in the world, offering unparalleled exposure to photons with energies above $5 \times 10^{16}$ eV. Since the start of data collection almost two decades ago, numerous searches for photons have been conducted using the detection systems of the Observatory. These searches have led to the most stringent upper limits on the diffuse photon flux. These limits place severe constraints on current models regarding the origin of ultra-high-energy cosmic rays and emphasize the significant capabilities of the Pierre Auger Observatory in the context of multimessenger astronomy at the highest energies. This contribution provides an overview of the ongoing efforts to search for high-energy photons in the data from the Pierre Auger Observatory. The latest results from searches for the diffuse photon flux will be presented, along with follow-up investigations for photons associated with transient events, such as gravitational wave detections. Furthermore, future prospects will be discussed in light of the ongoing AugerPrime detector upgrade, which will enhance the sensitivity of the Observatory to photons up to the highest energies.

Stochastic inflation rests on the separate-universe approximation, i.e. the ability to describe long-wavelength fluctuations in an inflating universe as homogeneous perturbations of its background dynamics. Although this approximation is valid in most cases, it has been recently pointed out that it breaks down during transition periods between attractor and non-attractor phases. Such transitions are ubiquitous in single-field models giving rise to enhanced perturbations at small scales, that are required to form primordial black holes. The current inability to apply the stochastic-inflation program in such models is therefore one of the main obstacles to investigating the role of backreaction in primordial-black-hole scenarios. In this work, we show how gradient interactions can be incorporated in stochastic inflation, via a set of Langevin equations of higher dimension. We apply our formalism to a few cases of interest, including one with a sharp transition. In all cases, in the classical limit we show that gradient corrections as predicted from cosmological perturbation theory are properly recovered. We uncover the existence of a "pullback" effect by which the tails of the first-passage-time distributions are dampened by gradient interactions. We finally discuss the role of backreaction in the presence of gradient interactions.

Novae, characterized by sudden brightening in binary star systems, are categorized into classical novae (CNe) and recurrent novae (RNe) based on their recurrence timescales. However, identifying RNe, which occur within 100 years, presents observational challenges. A reasonable signature of RNe has been theorized and statistically validated to address this -- the presence of a plateau in the optical light curve. Among the known RNe, except T CrB and V3890 Sgr displaying S-class light curve, the rest 9 out of 11 have a P-class light curve. But classical novae can also present plateaus, which further complicates the problem of distinguishing CNe from RNe just based on plateau. Hence, in this study, we aim to conduct a phenomenological analysis of P-class light curves to comment on the recurrence nature of novae. We utilize data primarily from the AAVSO database and identify a parameter space to represent all P-class light curves, anticipating distinct parameter distributions for CNe and RNe. Analysis of parameter distributions successfully distinguishes RNe from CNe and reveals potential connections with white dwarf mass and mass accretion rate, which are the key factors. Our method indicates KT Eri to be a recurrent nova, consistent with a recent study, despite only one observed outburst. The analysis also indicates the possibility of recurrence for V2860 Ori, a prediction that may be tested by deep search for nova super-remnant for this source. Our method demonstrates the feasibility of distinguishing P-class classical and recurrent novae based solely on the optical light curve. As observations of new novae increase, this method holds promise for more precise predictions of nova recurrence nature in the future.

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) flew in May of 2023, marking an important step towards the observation of ultra-high-energy cosmic rays (UHECR) and neutrino-induced showers from space. The ultimate goal of this endeavor is to complement ground-based detectors and achieve unprecedented exposure and nearly uniform full-sky coverage at the highest energies, thereby enabling charged particle astronomy and enriching the multi-messenger approach to high-energy astrophysics and astroparticle physics. As a pathfinder to the POEMMA mission (Probe Of Extreme Multi-Messenger Astrophysics), EUSO-SPB2 flew two distinct cameras at the focus of two Schmidt telescopes, one made of multi-anode photomultiplier tubes (MAPMTs), looking towards the nadir for fluorescence light detection, the other made of Silicon photomultipliers (SiPMs), looking towards the limb of the Earth for direct Cherenkov light detection. The flight was terminated prematurely due to a failure in the balloon, and thus no showers were detected in the fluorescence mode. However, several lower-energy (PeV scale) cosmic-ray events were observed in the Cherenkov channel. The data collected by both telescopes also confirmed the pertinence and maturity of the technology. We will report on the mission's cosmic ray results, and lessons learned for future balloon and satellite missions, notably the POEMMA Balloon with Radio (PBR), currently under development.

If nonrelativistic dark matter and radiation are allowed to interact, reaching an approximate thermal equilibrium, this interaction induces a bulk viscous pressure changing the effective one-fluid description of the universe dynamics. By modeling such components as perfect fluids, a cosmologically relevant bulk viscous pressure emerges for dark matter particle masses in the range of $1\,\text{eV} - 10\,\text{eV}$ keeping thermal equilibrium with the radiation. Such a transient bulk viscosity introduces significant effects in the expansion rate near the matter-radiation equality (redshift $z_{\text{eq}} \sim 3400$) and at late times (leading to a higher inferred value of the Hubble constant $H_0$). We use the recent DESI DR2 BAO data to place an upper bound on the free parameter of the model $\tau_\text{eq}$ which represents the time scale in which each component follows its own internal perfect fluid dynamics until thermalization occurs. Our main result is encoded in the bound $\tau_\text{eq} < 1.84 \times 10^{-10} $ s (2$\sigma$), with the corresponding dimensionless bulk coefficient $\tilde{\xi} H_0/H_{eq}<5.94\times10^{-4}$ (2$\sigma$). In practice, this rules out any possible interaction between radiation and dark matter prior to the recombination epoch.

The next generation of imaging surveys, including the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), Euclid, and the Nancy Grace Roman Space Telescope, will place unprecedented constraints on cosmology using weak gravitational lensing. To fully exploit their statistical power, shear measurement methods must achieve sub-percent accuracy while mitigating systematic biases from noise, the point-spread function (PSF), blending, and shear-dependent detection. The analytical calibration framework (\texttt{AnaCal}) has demonstrated such accuracy but requires adding noise to images, reducing their effective depth. We introduce Deep-Field Analytical Calibration (\textsc{deep-field~}\texttt{AnaCal}), an extension of \texttt{AnaCal} that leverages deep-field images to compute shear responses while preserving wide-field statistical power. We validate the method on isolated and blended galaxy simulations with LSST-like seeing and noise, showing it meets the stringent requirement of multiplicative bias $|m| < 3\times10^{-3}$ at 99.7% confidence. Relative to standard \texttt{AnaCal} on wide-field images, this method improves effective galaxy number density from $17$ to $30$ arcmin$^{-2}$ for simulated 10-year LSST data. Assuming deep fields with $10\times$ the exposure of wide fields, we find the pixel noise variance in shear estimation is reduced by $30%$ and the overall shear uncertainty by $\sim 25%$. Finally, we assess sample variance impacts using the LSST Deep Drilling Fields strategy, finding an equivalent calibration uncertainty of $\lesssim 0.3%$. These results establish \textsc{deep-field~}\texttt{AnaCal} as a promising approach for shear calibration in upcoming weak lensing surveys.

The quenching of star formation in galaxies is an important aspect of galaxy evolution, but the physical mechanisms that drive it are still not understood. Measuring the spatial distribution of quenching can help determine these mechanisms. We present the star-formation histories (SFHs) and stellar metallicity evolution of rapidly quenched regions in 86 local post-starburst (PSB) galaxies from the MaNGA integral field survey, obtained through Bayesian full spectral fitting of their rest-frame optical spectra. We found that regardless of spatial location, the PSB regions have similar past SFHs and chemical evolution, once radial metallicity gradients are accounted for. This suggests that all PSB regions are regulated by a common set of local scale processes in the interstellar medium, regardless of the broader triggering mechanism. We show that the centres of galaxies with outer PSB regions are also quenching. The central specific star-formation rate (sSFR) has declined by $\sim1.0\;$dex on average during the last 2 Gyr, a significantly steeper decline than main sequence galaxies over the same period ($\approx0.2\;$dex). This central quenching can be either synchronous, outside-in or inside-out, and slower or as fast as the outer regions, highlighting the diversity of quenching pathways for local galaxies. Our results imply a primary quenching mechanism that is both catastrophic and global in rapidly halting star formation in local galaxies. We suggest the predominant cause is galaxy mergers or interactions, with large scale feedback from a starburst or a central supermassive black hole playing a lesser role.

We report the milliarcsecond localization of a high (1379 pc/cc) dispersion measure (DM) repeating fast radio burst, FRB 20190417A. Combining European VLBI Network detections of five repeat bursts, we confirm the FRB's host to be a low-metallicity, star-forming dwarf galaxy at z = 0.12817, analogous to the hosts of FRBs 20121102A, 20190520B and 20240114A. We also show that FRB 20190417A is spatially coincident with a compact, luminous persistent radio source (PRS). Visibility-domain model fitting constrains the transverse physical size of the PRS to < 23.1 pc and yields an integrated flux density of 191(39) microJy at 1.4 GHz. Though we do not find significant evidence for DM evolution, FRB 20190417A exhibits a time-variable rotation measure (RM) ranging between +3958(11) and +5061(24) rad/m2 over three years. We find no evidence for intervening galaxy clusters in the FRB's line-of-sight and place a conservative lower limit on the rest-frame host DM contribution of 1212.0 pc/cc (90% confidence) -- the largest known for any FRB so far. This system strengthens the emerging picture of a rare subclass of repeating FRBs with large and variable RMs, above-average host DMs, and luminous PRS counterparts in metal-poor dwarf galaxies. We explore the role of these systems in the broader FRB population, either as the youngest or most extreme FRB sources, or as a distinct engine for FRB emission.

We present a hybrid active galactic nucleus (AGN) feedback model that features three accretion disc states (the thick, thin, and slim discs at low, moderate, and super-Eddington accretion rates, respectively), and two feedback modes: thermal isotropic and kinetic jets. The model includes black hole (BH) spin evolution due to gas accretion, BH mergers, jet spindown, and Lense-Thirring torques. The BH spin determines the jet directions and affects the feedback efficiencies. The model is implemented in the SWIFT code and coupled with the COLIBRE galaxy formation model. We present the first results from hybrid AGN feedback simulations run as part of the COLIBRE suite, focusing on the impact of new parameters and calibration efforts. Using the new hybrid AGN feedback model, we find that AGN feedback affects not just massive galaxies, but all galaxies down to $M_*\approx10^8$ $\mathrm{M}_\odot$. BH spins are predicted to be near-maximal for intermediate-mass BHs ($M_\mathrm{BH}\in[10^6,10^8]$ $\mathrm{M}_\odot$), and lower for other BH masses. These trends are in good agreement with observations. The intergalactic medium is hotter and impacted on larger scales in the hybrid AGN feedback simulations compared to those using purely thermal feedback. In the hybrid AGN simulations, we predict that half of the cumulative injected AGN energy is in thermal and the other half in jet form, broadly independent of BH mass and redshift. Jet feedback is important at all redshifts and dominates over thermal feedback at $z<0.5$ and $z>1.5$, but only mildly.

In recent years, the number of white dwarfs (WDs) showing infrared (IR) excesses, attributed to circumstellar dust disks, has grown significantly. Gaseous disks have also been detected in some WDs with dust. We obtained optical spectra with Gemini/GMOS for thirteen WDs exhibiting IR excesses to search for gaseous components. No Ca II emission was detected, suggesting the gas phase may be short-lived compared to the dusty stage. Combining our data with literature, we compiled the largest sample of WDs with and without gas disks. We find no significant differences in stellar properties between the two groups, although disks with gas may be, on average, brighter. The detection rate of Ca II emission supports the idea that the gas phase persists for only a fraction of the total disk lifetime. A more definitive assessment will likely require dedicated searches for both gas and dust across large WD samples.

We present the first polarimetric observations of the third discovered interstellar object, 3I/ATLAS (C/2025 N1), obtained pre-perihelion with FORS2/VLT, ALFOSC/NOT, and FoReRo2/RCC, over a phase angle range of 7.7-22.4°. This marks the second ever polarimetric study of an interstellar object, the first distinguishing 2I/Borisov from most Solar System comets by its higher positive polarisation. Our polarimetric measurements as a function of phase angle reveal that 3I is characterised by an deep and narrow negative polarisation branch, reaching a minimum value of -2.7% at phase angle 7°, and an inversion angle of 17° -- a combination unprecedented among asteroids and comets, including 2I/Borisov. At very small phase angles, the extrapolated slope of the polarisation phase curve is consistent with that of certain small trans-Neptunian objects and Centaur Pholus, consistent with independent spectroscopic evidence for a red, possibly water-ice-bearing object. Imaging confirms a diffuse coma present from our earliest observations, though no strong polarimetric features are spatial resolved. These findings may demonstrate that 3I represents a distinct type of comet, expanding the diversity of known interstellar bodies.

Rapid progress in cosmological Large Scale Structure (LSS) surveys motivates precise theoretical predictions. The Effective Field Theory of Large-Scale Structure (EFTofLSS) is routinely applied to data, and requires fast computation of its predictions when sampling the large space of cosmological parameters. Going beyond existing one-loop techniques, we present a method to rapidly evaluate the two-loop power spectrum. Our method decomposes the typically small difference between a given linear power spectrum and a reference power spectrum into a cosmology-independent basis of functions resembling massive scalar propagators in Quantum Field Theory. By taking the leading terms in such a small difference, we numerically evaluate the cosmology-independent loop integrals where in the integrand only the relevant combinations of basis functions appear. We achieve an efficient numerical evaluation via physically motivated local ultraviolet subtractions and by arranging the cancellation of infrared singularities locally in the integrands. Final predictions are obtained by contracting these precomputed integrals with the cosmology-dependent coordinates of the expansion in the fixed basis. We present and publicly release the precomputed integrals for the renormalized two-loop dark-matter power spectrum in the EFTofLSS. These require eight EFT counterterms, which include the effect of generated vorticity, and are sufficient to analyze the lensing galaxy signal in LSS surveys at this order.

Doppler shifts in chromospheric and transition-region lines during solar flares are often interpreted as chromospheric condensation or evaporation. However, alternative sources of Doppler-shifted emission have been suggested, such as filament eruptions, jets or chromospheric bubbles. We analyse high-cadence scans from SORCE/SOLSTICE, which provide one-minute resolution profiles of the transition-region Si~\textsc{iii} ($1206\,\textrm{Å}$, $\textrm{T} = 10^{4.6}\,\textrm{K}$) line. 11 X-, M-, and C-class events observed during these scans with clear impulsive phase Si~\textsc{iii} enhancements were identified. By subtracting a quiet-Sun profile and fitting Gaussian profiles to the Si~\textsc{iii} line, measurements of flare-induced Doppler shifts were made. After correcting for a systematic trend in these shifts with solar longitude, two of the 11 events were found to exhibit a significant Doppler shift, \comment{}one with a $201.36\pm21.94\;\textrm{km\,s}^{-1}$ redshift and the other with a $-39.75\pm11.00\;\textrm{km\,s}^{-1}$ blueshift\commentend{}. Intriguingly, SDO/AIA $304\,\textrm{Å}$ and $1600\,\textrm{Å}$ imaging revealed a bright eruption coincident with the event that exhibited a blueshift, suggesting the shift may have resulted from the eruption rather than evaporation alone. Our results highlight Si~\textsc{iii} as a useful diagnostic of flaring dynamics at a temperature that has received limited attention to date. Future comparisons of these observations with radiative hydrodynamic simulations, along with new observations from state-of-the-art spectrometers such as SOLAR-C/EUVST and MUSE, should clarify the mechanisms behind the observed shifts in this study.

The solar chemical composition is a fundamental yardstick in astrophysics and the topic of heated debate in recent literature. We re-evaluate the abundance of sulphur in the photosphere by studying seven S I lines in the solar disc-centre intensity spectrum. Our analysis considers independent sets of experimental and theoretical oscillator strengths together with, for the first time, three-dimensional non-local thermodynamic equilibrium (3D non-LTE) S I spectrum synthesis. Our best estimate is $A(\mathrm{S})=7.06\pm0.04$, which is $0.06$ dex to $0.10$ dex lower than that in commonly-used compilations of the solar chemical composition. Our lower solar sulphur abundance deviates from that in CI chondrites, and thereby supports the case for a systematic difference between the composition of the solar photosphere and of CI chondrites that is correlated with $50\%$ condensation temperature. We suggest that precise laboratory measurements of S I oscillator strengths and abundance analyses using 3D magnetohydrodynamic models of the solar photosphere be conducted to further substantiate our conclusions.

This study investigates the statistical behavior of plasma properties during Hot Onset Precursor Events (HOPEs) of solar flares and evaluates their potential for improving flare nowcasting. Two datasets are analyzed: (a) new Soft X-Ray (SXR) spectra of 25 flares (C2.6 to M1.0) obtained from the Dual-zone Aperture X-ray Solar Spectrometer (DAXSS), and (b) SXR irradiance data from 137 flares (C5.0 to X7.1) recorded by the X-Ray Sensor on the Geostationary Operational Environmental Satellite (GOES-XRS). Plasma temperature, emission measure (EM), and low First Ionization Potential (e.g., Mg, Si, Fe) elemental abundance factors (AFs) are derived from DAXSS using Astrophysical Plasma Emission Code model fitting. Isothermal plasma temperature and emission measure are derived from GOES-XRS using the XRS-A/XRS-B ratio method. Results indicate that the HOPE phase exhibits elevated temperatures (10-15 MK) and an order-of-magnitude increase in EM before the impulsive phase. Elemental AFs show a transition from coronal to photospheric values as the flare progresses. Using GOES-XRS data, we develop an improved nowcasting algorithm that detects flares utilizing HOPE signatures. The algorithm is tested across three categories of flares (C5.0-M1.0, M1.0-X1.0, and X1.0+), consistently predicting flare alerts 5-15 minutes ahead of the flare peak. We also explore the possibility of approximate flare magnitude prediction, by calculating correlation between onset parameters and flare peak magnitude. This HOPE-based system shows potential for earlier warnings than current NOAA R3 alerts, which could be useful for High-frequency communication systems operators and targeted flare observation campaigns.

We present the first X-ray polarimetry observations of a redback millisecond pulsar binary, \src, with the Imaging X-ray Polarimetry Explorer (IXPE). Redbacks are compact binaries in which a rotation-powered millisecond pulsar interacts with a non-degenerate companion via an intrabinary shock, forming ideal laboratories for probing pulsar winds and relativistic shock physics, where ordered magnetic fields and particle acceleration shape the observed radiation. We conduct a spectro-polarimetric analysis combining IXPE data with archival Chandra, XMM-Newton, NuSTAR, and Swift observations. We explore two limiting magnetic field configurations, parallel and perpendicular to the bulk flow, and simulate their expected polarization signatures using the {\tt 3DPol} radiative transport code. To account for the rapid rotation of the polarization angle predicted by these models, we implement a phase-dependent Stokes alignment procedure that preserves the polarization degree while correcting for phase-rotating PA. We also devise a new maximum-likelihood fitting strategy to determine the phase-dependence of the polarization angle by minimizing the polarization degree uncertainty. This technique shows a hint the binary may be rotating clockwise relative to the celestial north pole. We find no significant detection of polarization in the IXPE data, with PD<51% at 99% confidence level. Our results excludes the high-polarization degree scenario predicted by the perpendicular field model during the brightest orbital phase bin. Simulations show that doubling the current exposure would make the parallel configuration detectable. The new PA rotation technique is also applicable to IXPE data of many sources whose intrinsic PA variation is apriori not known but is strictly periodic.

Mass transfer (MT) is a fundamental process in stellar evolution. While MT in circular orbits is well studied, observations indicate that it also occurs in eccentric ones. To date, no framework simultaneously accounts for both conservative and non-conservative MT across arbitrary eccentricities while also incorporating the donor star`s spin. We present a new semi-analytic framework for the secular orbital evolution of mass-transferring binaries, treating stars as extended bodies and accounting for the donor star`s spin. The model is applicable to both circular and eccentric orbits and accommodates conservative and non-conservative MT across a broad range of mass ratios and stellar spins. We derive secular, orbit-averaged equations describing the orbital evolution by treating MT, mass loss, and angular momentum loss as perturbations to the general two-body problem. Assuming conservative MT, we compare our results to previous models and validate them against numerical integrations. Our model predicts stronger orbital widening at a given mass ratio than previous models. For circular orbits, we find that the transitional mass ratio $q_{trans,a}$, which separates orbital widening from shrinkage, increases from $q_{trans,a} = 1$ up to $q_{trans,a} \sim 1.5$ when accounting for extended bodies. For eccentric orbits, the model predicts a broader parameter space for both orbital widening and eccentricity pumping. We find that stable MT naturally explains the observed correlation between longer orbital periods and higher eccentricities, providing a robust mechanism for the formation of wide and eccentric post-interaction binaries. Our model can be integrated into binary evolution and population synthesis codes to consistently treat conservative and non-conservative MT in arbitrarily eccentric orbits with applications ranging from MT on the main sequence to gravitational-wave progenitors.

The concept of prominence is familiar to signal engineers, topographers and mountaineers. We introduce Prominence $\mathcal P$ as a discriminator of gravitational wave (GW) signals. We treat black hole and neutron star binaries as astrophysical background sources, and show how $\mathcal P$ can be used to distinguish between GW spectra produced by first-order phase transitions, domain walls and cosmic strings, and combinations thereof. Prominence can also be used to discriminate between these and off-piste sources of GWs. The uncertainty in the measured energy density in GWs at Pulsar Timing Arrays needs to be smaller than $\sim 4\%$ for $\mathcal{P}$ to achieve discrimination at 3$\sigma$. LISA and ET data are expected to have sufficiently small uncertainties that Prominence can play a central role in their analysis.

We investigate interacting dark energy (IDE) models with phenomenological, non-linear interaction kernels $Q$, specifically $Q_{1}=3H\delta \left(\frac{\rho_{\rm dm}\rho_{\rm de}}{\rho_{\rm dm}+\rho_{\rm de}}\right)$, $Q_{2}=3H\delta \left(\frac{\rho_{\rm dm}^2}{\rho_{\rm dm}+\rho_{\rm de}}\right)$, and $Q_{3}=3H\delta \left(\frac{\rho_{\rm de}^2}{\rho_{\rm dm}+\rho_{\rm de}}\right)$. Using dynamical system techniques developed in our companion paper on linear kernels, we derive new conditions that ensure positive and well-defined energy densities, as well as criteria to avoid future big rip singularities. We find that for $Q_{1}$, all densities remain positive, while for $Q_{2}$ and $Q_{3}$ negative values of either DM or DE are unavoidable if energy flows from DM to DE. We also show that for $Q_{1}$ and $Q_{2}$ a big rip singularity always arises in the phantom regime $w<-1$, whereas for $Q_{3}$ this fate may be avoided if energy flows from DE to DM. In addition, we provide new exact analytical solutions for $\rho_{\rm dm}$ and $\rho_{\rm de}$ in the cases of $Q_{2}$ and $Q_{3}$, and obtain new expressions for the effective equations of state of DM, DE, the total fluid, and the reconstructed dynamical DE equation of state ($w_{\rm dm}^{\rm eff}$, $w_{\rm de}^{\rm eff}$, $w_{\rm tot}^{\rm eff}$, and $\tilde{w}$). Using these results, we discuss phantom crossings, evaluate how each kernel addresses the coincidence problem, and apply statefinder diagnostics to compare the models. These findings extend the theoretical understanding of non-linear IDE models and provide analytical tools for future observational constraints.

Interacting dark energy (IDE) models, in which dark matter (DM) and dark energy (DE) exchange energy through a non-gravitational interaction, have long been proposed as candidates to address key challenges in modern cosmology. These include the coincidence problem, the $H_0$ and $S_8$ tensions, and, more recently, the hints of dynamical dark energy reported by the DESI collaboration. Given the renewed interest in IDE models, it is crucial to fully understand their parameter space when constraining them observationally, especially with regard to the often-neglected issues of negative energy densities and future big rip singularities. In this work, we present a comparative study of the general linear interaction $Q=3H(\delta_{\rm dm}\rho_{\rm dm} + \delta_{\rm de}\rho_{\rm de})$ and four special cases: $Q=3H\delta(\rho_{\rm dm}+\rho_{\rm de})$, $Q=3H\delta(\rho_{\rm dm}-\rho_{\rm de})$, $Q=3H\delta \rho_{\rm dm}$, and $Q=3H\delta \rho_{\rm de}$. For these five models, we perform a dynamical system analysis and derive new conditions that ensure positive, real, and well-defined energy densities throughout cosmic evolution, as well as criteria to avoid future big rip singularities. We obtain exact analytical solutions for $\rho_{\rm{dm}}$, $\rho_{\rm{de}}$, the effective equations of state ($w_{\mathrm{eff}}^{\rm{dm}}$, $w_{\mathrm{eff}}^{\rm{de}}$, $w_{\mathrm{eff}}^{\rm{tot}}$), and a reconstructed dynamical DE equation of state $\tilde{w}$. Using these results, we examine phantom crossings, address the coincidence problem, and apply the statefinder diagnostic to distinguish between models. We show that energy transfer from DM to DE inevitably produces negative energy densities and make future singularities more likely, while transfer from DE to DM avoids these pathologies and is thus theoretically favored.

We present an overview of the main results from our two companion papers that are relevant for observational constraints on interacting dark energy (IDE) models. We provide analytical solutions for the dark matter and dark energy densities, $\rho_{\rm dm}$ and $\rho_{\rm de}$, as well as the normalized Hubble function $h(z)$, for eight IDE models. These include five linear IDE models, namely $Q=3H(\delta_{\rm dm} \rho_{\rm dm} + \delta_{\rm de} \rho_{\rm de})$ and four special cases: $Q=3H\delta(\rho_{\rm dm}+\rho_{\rm de})$, $Q=3H\delta(\rho_{\rm dm}-\rho_{\rm de})$, $Q=3H\delta \rho_{\rm dm}$, and $Q=3H\delta \rho_{\rm de}$, together with three non-linear IDE models: $Q=3H\delta \left( \tfrac{\rho_{\rm dm} \rho_{\rm de}}{\rho_{\rm dm}+\rho_{\rm de}} \right)$, $Q=3H\delta \left( \tfrac{\rho_{\rm dm}^2}{\rho_{\rm dm}+\rho_{\rm de}} \right)$, and $Q=3H\delta \left( \tfrac{\rho_{\rm de}^2}{\rho_{\rm dm}+\rho_{\rm de}} \right)$. For these eight models, we present conditions to avoid imaginary, undefined, and negative energy densities. In seven of the eight cases, negative densities arise if energy flows from DM to DE, implying a strong theoretical preference for energy transfer from DE to DM. We also provide conditions to avoid future big rip singularities and evaluate how each model addresses the coincidence problem in both the past and the future. Finally, we propose a set of approaches and simplifying assumptions that can be used when constraining IDE models, by defining regimes that restrict the parameter space according to the behavior researchers are willing to tolerate.

Turbulence in curved spacetimes in general, and in the vicinity of black holes (BHs) in particular, represents a poorly understood phenomenon that is often analysed employing techniques developed for flat spacetimes. We here propose a novel approach to study turbulence in strong gravitational fields that is based on the computation of structure functions on generic manifolds and is thus applicable to arbitrary curved spacetimes. In particular, we introduce, for the first time, a formalism to compute the characteristic properties of turbulence, such as the second-order structure function or the power spectral density, in terms of proper lengths and volumes and not in terms of coordinate lengths and volumes, as customarily done. By applying the new approach to the turbulent rest-mass density field from simulations of magnetised disc accretion onto a Kerr BH, we inspect in a rigorous way turbulence in regions close to the event horizon, but also in the disc, the wind, and in the jet. We demonstrate that the new approach can capture the typical behavior of an inertial-range cascade and that differences up to $40-80\%$ emerge in the vicinity of the event horizon with respect to the standard flat-spacetime approach. While these differences become smaller at larger distances, our study highlights that special care needs to be paid when analysing turbulence in strongly curved spacetimes.

Numerical weather prediction requires initial estimates of the atmospheric state. Since the atmospheric density field is intricately woven into the atmosphere's governing equations, advancing atmospheric density estimation will improve numerical weather prediction. However, current meteorological instrumentation cannot directly measure the atmospheric density field over large volumes. Existing techniques rely on sparse point measurements, limiting our ability to accurately estimate the three-dimensional atmospheric density field. One potential solution is to employ measurements of the atmospheric muon flux. Atmospheric muons are particles produced when energetic atomic nuclei (cosmic rays) collide with nuclei in the upper atmosphere, producing a shower of secondary particles (muons) that propagates to the Earth's surface. The surface atmospheric muon flux is known to be proportional to the local atmospheric density field, implying that this technique can be used as a measurement of atmospheric density. This study examines the potential for using atmospheric muon flux measurements to improve atmospheric state estimation via a case study of simulated atmospheric muon observations in the path of tropical cyclone Freddy. We show that improvement in data assimilation performance can be achieved using data from a relatively small astroparticle detector, well within the capabilities of existing astroparticle technology. We additionally show that the improvements to atmospheric state estimates associated with muon flux assimilation are at least partially unique to muon flux measurements, as comparable surface pressure point measurements do not reproduce a similar effect.

We propose a novel non-singular cosmological scenario within the framework of Horndeski gravity, consisting of three successive stages: (i) a Genesis phase, in which the Universe slowly expands from an asymptotically flat spacetime; (ii) a brief transition stage restoring General Relativity; and (iii) a Starobinsky inflationary phase. This construction is fully consistent within a viable parameter space: it remains weakly coupled, free from ghost and gradient instabilities, with luminal tensor and subluminal scalar perturbations throughout the entire evolution. Importantly, the Genesis phase induces characteristic corrections to the Starobinsky potential, which cannot be captured by simple $\sum_i c_i R^i$-type modifications. These corrections robustly enhance the scalar spectral index, thereby improving the agreement of Starobinsky inflation with recent CMB measurements, in particular the data from the Atacama Cosmology Telescope (ACT).

A thermodynamic description of cosmological spacetimes may provide insights into the fundamentals of the cosmic evolution that remain otherwise obscure, in close analogy with 'black hole thermodynamics'. We investigate the thermodynamic properties of late-time cosmological evolution using the dynamical systems approach, focusing on the $\Lambda$CDM model and quintessence models with an exponential potential. Thermodynamic quantities obtained through the Hayward-Kodama formalism are mapped onto the phase space of these models, allowing us to investigate thermodynamic stability and phase transitions in a manner independent of the initial condition of the evolution of the universe. In both models, the universe inevitably undergoes a thermodynamic phase transition, marked by diverging specific heats, irrespective of its initial configuration. We further demonstrate that the thermodynamic stability can occur only during an accelerating phase of the universe. However, the necessary stability conditions are never satisfied anywhere in the phase space, rendering both models inherently thermodynamically unstable within the Hayward-Kodama framework. Importantly, our analysis highlights the dynamical system approach as a natural and powerful framework to probe the thermodynamic aspects of cosmological evolution.

We study gravitational waves induced by scalar primordial fluctuations in Gleyzes-Langlois-Piazza-Vernizzi (GLPV), beyond Horndeski, scalar-tensor theories. We uncover, at the level of the action, a new scalar-scalar-tensor interaction, unique to GLPV models disconnected from Horndeski via disformal transformation. The new interaction leads to third derivatives in the source for scalar-induced tensor modes, which are absent in Horndeski-related theories. Such new higher-derivative terms lead to a further enhanced production of induced gravitational waves. We predict that for a scale-invariant primordial spectrum, the induced gravitational wave spectral density has a characteristic frequency dependence proportional to $f^5$. Such a fast-rising spectrum offers a potential unique signature of modified gravity in the early universe.

We study the possibility that the Right-handed neutrino is a five-dimensional state propagating along a micron size extra dimension, as required in the dark dimension proposal. We work out the signatures of R-neutrino production in KATRIN experiment and compare them with those of a sterile neutrino which manifests by a kink in the electron energy spectrum of the beta-decay at a value corresponding to the sterile neutrino mass. We explore the allowed parameter space of the compactification scale and the R-neutrino bulk mass versus the Yukawa coupling, and show that a large part of it is within KATRIN's sensitivity. When the bulk mass is much smaller than the compactification scale, several kinks could be observed corresponding to the positions of the R-neutrino Kaluza-Klein excitations, while for large bulk mass there will be effectively one kink at the position of the bulk mass.

We propose that the infrared (IR) running of Newton's coupling provides a simple and universal explanation for large--distance modifications of gravity relevant to dark matter phenomenology. Within the effective field theory (EFT) framework, we model $G(k)$ as a scale--dependent coupling governed by an anomalous dimension $\eta$. We show that the marginal case $\eta = 1$ is singled out by renormalization group (RG) and dimensional arguments, leading to a logarithmic potential and a $1/r$ force law at large distances, while smoothly recovering Newtonian gravity at short scales. The logarithmic correction is universal and regulator independent, indicating that the $1/r$ force arises as the robust IR imprint of quantum--field--theoretic scaling. This provides a principled alternative to particle dark matter, suggesting that galactic rotation curves and related anomalies may be understood as manifestations of the IR running of Newton's constant.