Papers for Monday, Feb 03 2025

In this work, I re-examine the question of a possible explanation for the anomalous advance of Mercury's perihelion by the existence of a hypothetical planet, Vulcan, which I consider to be a kind of primordial black hole of planetary-mass. The detection of this kind of celestial body has become possible with modern experimental techniques, inter alia, such as the Optical Gravitational Lensing Experiment. Recently, an excess of ultra-short microlensing events with crossing times of 0.1 to 0.3 days has been reported, suggesting the possible existence of sub-Earth-mass primordial black holes in our solar system. The primordial black hole Vulcan planetary mass hypothesis could then explain the anomalous advance of Mercury's perihelion under the influence of its gravitational attraction, still remaining hidden from astronomers' telescopes. But in this case, it will also influence the perihelion advance of the other planets. To this end, I first calculate the mutual partial contributions to the perihelion motion of all the planets by two different methods without Vulcan in a model of simplified solar system consisting of the Sun and eight planets. Next, I include Vulcan in this model within the framework of the Newtonian theory of classical gravitation and analyze Vulcan's influence on the perihelion advance of the inner planets, using Vulcan parameters from my previous work. These results are compared with the perihelion advances of the inner planets predicted by the theory of general relativity, and with the data obtained by modern observations.

The intense magnetic fields present in neutron stars are closely linked to their observed temperature and spectral characteristics, timing properties, including spin period and its derivatives. Therefore, a comprehensive theoretical analysis of magnetic field evolution is essential for understanding how the strength of the magnetic field change over time. The decay rate of magnetic field in isolated, non-accreting neutron stars can be assessed by evaluating the second derivative of the spin frequency. Another method to estimate this rate involves monitoring an increase in thermal emission beyond what is expected from standard cooling processes, assuming no additional heating mechanisms are present. Our findings indicate that for X-ray emitting isolated neutron stars, the evolution rate of spin period derivative aligns with the dissipation rate of magnetic energy from the dipolar field, provided that a substantial portion of the released energy is emitted as X-rays. The time scale of magnetic field decay is found to be much shorter than typical age of radio pulsars.

The TOV equations govern the radial evolution of pressure and energy density in static neutron stars (NSs) in hydrodynamical equilibrium. Using the reduced pressure and energy density with respect to the NS central energy density, the original TOV equations can be recast into dimensionless forms. While the traditionally used integral approach for solving the original TOV equations require an input nuclear Equation of State (EOS), the dimensionless TOV equations can be anatomized by using the reduced pressure and energy density as polynomials of the reduced radial coordinate without using any input nuclear EOS. Interesting and novel perspectives about NS core EOS can be extracted directly from NS observables using this new approach based on Intrinsic and Perturbative Analyses of the Dimensionless (IPAD) TOV equations (IPAD-TOV). In this review, we first discuss the length and energy density scales of NSs as well as the dimensionless TOV equations for scaled variables and their perturbative solutions near NS cores. We then review several new insights into NS physics gained from using the IPAD-TOV. We also demonstrate that the strong-field gravity plays a fundamental role in extruding a peak in the density/radius profile of the speed of sound squared (SSS) in massive NS cores independent of the nuclear EOS. Finally, some future perspectives of NS research using the IPAD-TOV are outlined.

The circumgalactic medium (CGM) plays a critical role in galaxy evolution, influencing gas flows, feedback processes, and galactic dynamics. Observations show a substantial cold gas reservoir in the CGM, but the mechanisms driving its formation and evolution remain unclear. Cosmic rays (CRs), as a source of non-thermal pressure, are increasingly recognized as key regulators of cold gas dynamics. This study explores how CRs affect cold clouds that condense from the hot CGM via thermal instability (TI). Using 3D CR-magnetohydrodynamic (CRMHD) simulations with AREPO, we assess the impact of various CR transport models on cold gas evolution. Under purely advective CR transport, CR pressure significantly suppresses the collapse of thermally unstable regions, altering the CGM's structure. In contrast, realistic CR transport models reveal that CRs escape collapsing regions via streaming and diffusion along magnetic fields, diminishing their influence on the thermal and dynamic structure of the cold CGM. The ratio of the CR escape time to the cloud collapse time emerges as a critical factor in determining the impact of CRs on TI. CRs remain confined within cold clouds when effective CR diffusion is slow which maximizes their pressure support and inhibits collapse. Fast effective CR diffusion, as realized in our 2-moment CRMHD model, facilitates rapid CR escape, reducing their stabilizing effect. This realistic CR transport model shows a wide dynamic range of the effective CR diffusion coefficient, ranging from $10^{29}$ to $10^{30}\,\mathrm{cm^{2}\,s^{-1}}$ for thermally- to CR-dominated atmospheres, respectively. In addition to these CR transport-related effects, we demonstrate that high numerical resolution is crucial to avoid spuriously large clouds formed in low-resolution simulations, which would result in overly long CR escape times and artificially amplified CR pressure support.

Assessing the prevalence of atmospheres on rocky planets around M-dwarf stars is a top priority of exoplanet science. High-energy activity from M-dwarfs can destroy the atmospheres of these planets, which could explain the lack of atmosphere detections to date. Volcanic outgassing has been proposed as a mechanism to replenish the atmospheres of tidally-heated rocky planets. L 98-59 b, a sub-Earth transiting a nearby M dwarf, was recently identified as the most promising exoplanet to detect a volcanic atmosphere. We present the transmission spectrum of L 98-59 b from four transits observed with JWST NIRSpec G395H. Although the airless model provides an adequate fit to the data based on its $\chi^2$, an SO$_2$ atmosphere is preferred by 3.6$\sigma$ over a flat line in terms of the Bayesian evidence. Such an atmosphere would likely be in a steady state where volcanism balances escape. If so, L 98-59 b must experience at least eight times as much volcanism and tidal heating per unit mass as Io. If volcanism is driven by runaway melting of the mantle, we predict the existence of a subsurface magma ocean in L 98-59 b extending up to $R_p\sim 60-90\%$. An SO$_2$-rich volcanic atmosphere on L 98-59 b would be indicative of an oxidized mantle with an oxygen fugacity of $f\rm{O}_2>IW+2.7$, and it would imply that L 98-59 b must have retained some of its volatile endowment despite its proximity to its star. Our findings suggest that volcanism may revive secondary atmospheres on tidally heated rocky planets around M-dwarfs.

Gamma and X-ray observatories have revealed spectacular structures in the emission of the tenuous hot gas surrounding the Milky Way (MW), known as the Fermi and eROSITA bubbles. Galaxy formation simulations suggest that MW-like bubbles could be ubiquitous, but their emission may be too faint to detect with today's instruments in individual external galaxies. In this paper, we present an analysis of stacked Chandra observations of 93 nearby galaxies. We detected soft, diffuse X-rays from the CGM, extending up to 14 kpc, with a luminosity of $(4.2\pm0.7)\times10^{39}$ erg/s in the $0.3-2$ keV band. To probe its spatial distribution, we constructed an azimuthal profile and found a significant enhancement along the galactic minor axis. When dividing our sample by stellar mass, central supermassive black hole mass, and star formation rate, we found that only high star formation rate galaxies exhibit significant anisotropies in the CGM emission. To investigate whether the observed anisotropies could be attributed to MW-like bubbles, we compared our results with TNG50 simulations. In these simulations, X-ray bubbles are strongly correlated with mass of the central supermassive black hole and typically extend to much larger, $\sim50$ kpc, scales. We conclude that the observed anisotropies are either caused by AGN-driven MW-like bubbles confined to smaller, $\sim10$ kpc, scales, or by star formation- or starburst-driven bubbles/outflows.

The dynamical formation of binary black holes (BBHs) in globular clusters (GCs) may contribute significantly to the observed gravitational wave (GW) merger rate. Furthermore, LISA may detect many BBH sources from GCs at mHz frequencies, enabling the characterization of such systems within the Milky Way and nearby Universe. In this work, we use Monte Carlo N-body simulations to construct a realistic sample of Galactic clusters, thus estimating the population, detectability, and parameter measurement accuracy of BBHs hosted within them. In particular, we show that the GW signal from $0.7\pm 0.7$, $2.0\pm 1.7$, $3.6\pm 2.3$, $13.4\pm 4.7$ BBHs in Milky Way GCs can exceed the signal-to-noise ratio threshold of $\rm SNR =30$, 5, 3, and 1 for a 10-year LISA observation, with $\sim 50\%$ of detectable sources exhibiting high eccentricities ($e\gtrsim0.9$). Moreover, the Fisher matrix and Bayesian analyses of the GW signals indicate these systems typically feature highly-resolved orbital frequencies ($\delta f_{\rm orb}/ f_{\rm orb} \sim 10^{-7}-10^{-5}$) and eccentricities ($\delta e/ e \sim 10^{-3}-0.1$), as well as a measurable total mass when SNR exceeds $\sim20$. Notably, BBHs with $\rm SNR\gtrsim 20$ can be confidently localized to specific GCs within the Milky Way, with an angular resolution of $\sim 10-100$ arc minutes. The detection and localization of even a single BBH in a Galactic GC would allow accurate tracking of its long-term orbital evolution, enable a direct test of the role of GCs in BBH formation, and provide a unique probe into the evolutionary history of Galactic clusters.

We present observations of the Type IIP supernova (SN) 2024jlf, including spectroscopy beginning just 0.7 days ($\sim$17 hours) after first light. Rapid follow-up was enabled by the new $\texttt{BTSbot-nearby}$ program, which involves autonomously triggering target-of-opportunity requests for new transients in Zwicky Transient Facility data that are coincident with nearby ($D<60$ Mpc) galaxies and identified by the $\texttt{BTSbot}$ machine learning model. Early photometry and non-detections shortly prior to first light show that SN 2024jlf initially brightened by $>$4 mag/day, quicker than $\sim$90% of Type II SNe. Early spectra reveal weak flash ionization features: narrow, short-lived ($1.3 < \tau ~\mathrm{[d]} < 1.8$) emission lines of H$\alpha$, He II, and C IV. Assuming a wind velocity of $v_w=50$ km s$^{-1}$, these properties indicate that the red supergiant progenitor exhibited enhanced mass-loss in the last year before explosion. We constrain the mass-loss rate to $10^{-4} < \dot{M}~\mathrm{[M_\odot~yr^{-1}]} < 10^{-3}$ by matching observations to model grids from two independent radiative hydrodynamics codes. $\texttt{BTSbot-nearby}$ automation minimizes spectroscopic follow-up latency, enabling the observation of ephemeral early-time phenomena exhibited by transients.

Integral field units (IFU) have extended our knowledge of galactic properties to kpc (or, sometimes, even smaller) patches of galaxies. These scales are where the physics driving galaxy evolution (feedback, chemical enrichment, etc.) take place. Quantifying the spatially-resolved properties of galaxies, both observationally and theoretically, is therefore critical to our understanding of galaxy evolution. To this end, we investigate spatially-resolved scaling relations within central galaxies ($M_\star>10^{9.0}$) at $z=0$ in IllustrisTNG. We examine both the resolved star-forming main sequence (rSFMS) and the resolved mass-metallicity relation (rMZR) using $1~{\rm kpc}\times1~{\rm kpc}$ maps of galaxies. We find that the rSFMS in IllustrisTNG is well-described by a power-law, but has some dependence on the host galaxy's mass. Conversely, the rMZR for IllustrisTNG can be described by a single power-law at low stellar mass surface density that flattens at high surface densities and is independent of host galaxy mass. We find quantitative agreement in both the rSFMS and rMZR with recent IFU observational campaigns. Furthermore, we argue that the rSFMS is an indirect result of the Schmidt-Kennicutt (SK) law and local gas fraction relation, which are both independent of host galaxy properties. Finally, we expand upon a localized leaky-box model to study the evolution of idealized spaxels and find that it provides a good description of these resolved relations. The degree of agreement, however, between idealized spaxels and simulated spaxels depends on the `net' outflow rate for the spaxel, and the observed scaling relations indicate a preference for a low net outflow rate.

The first direct detection of gravitational waves in 2015 marked the beginning of a new era for the study of compact objects. Upcoming detectors, such as the Einstein Telescope, are expected to add thousands of binary coalescences to the list. However, from a theoretical perspective, our understanding of compact objects is hindered by many uncertainties, and a comprehensive study of the nature of stellar remnants from core-collapse supernovae is still lacking. In this work, we investigate the properties of stellar remnants using a homogeneous grid of rotating and non-rotating massive stars at various metallicities from Limongi and Chieffi 2018. We simulate the supernova explosion of the evolved progenitors using the HYdrodynamic Ppm Explosion with Radiation diffusION (HYPERION) code (Limongi and Chieffi 2020), assuming a thermal bomb model calibrated to match the main properties of SN1987A. We find that the heaviest black hole that can form depends on the initial stellar rotation, metallicity, and the assumed criterion for the onset of pulsational pair-instability supernovae. Non-rotating progenitors at $\big[\rm Fe/H \big]=-3$ can form black holes up to $\sim 87 M_\odot$, falling within the theorized pair-instability mass gap. Conversely, enhanced wind mass loss prevents the formation of BHs more massive than $\sim 41.6 M_\odot$ from rotating progenitors. We use our results to study the black hole mass distribution from a population of $10^6$ isolated massive stars following a Kroupa initial mass function. Finally, we provide fitting formulas to compute the mass of compact remnants as a function of stellar progenitor properties. Our up-to-date prescriptions can be easily implemented in rapid population synthesis codes.

We present the study of the gas kinematics in narrow-line regions (NLRs) of 2,009 type-2 AGNs at $z<0.34$. We construct the [O III]$\lambda$5007 emission-line images using publicly available broadband images from the Sloan Digital Sky Survey (SDSS). The [O III] emission area of the samples, measured down to $1.7\times10^{-15}$ erg/s/cm$^2$/arcsec$^2$, ranges from 3.7 kpc$^2$ up to 224 kpc$^2$. With our broadband technique, we found the strong correlation between [O III] area and AGN luminosity inferred from the [O III] luminosity and the mid-infrared luminosity at the rest-frame $15\mu$m. The isophotal threshold used to determine the [O III] area affects the correlation strength in that the brighter isophote yields the stronger correlation between the [O III] area and AGN luminosity. The presence of gas outflow is examined by the ratio of the [O III] velocity dispersion to the stellar velocity dispersion ($\sigma_{\rm [O\,III]}/\sigma_\star > 1.4$) using the SDSS spectra. At the given luminosity, the objects with and without outflows exhibit the same extension of the [O III] emission. Their correlation between the [O III] area and luminosity is almost identical. It is suggested that the size of NLRs is not affected by outflow mechanisms but rather by photoionization from the central AGNS.

Numerical hydrodynamics simulations of gases dominated by ideal, nondegenerate matter pressure and thermal radiation pressure in equilibrium entail finding the temperature as part of the evolution. Since the temperature is not typically a variable that is evolved independently, it must be extracted from the the evolved variables (e.g. the rest-mass density and specific internal energy). This extraction requires solving a quartic equation, which, in many applications, is done numerically using an iterative root-finding method. Here we show instead how the equation can be solved analytically and provide explicit expressions for the solution. We also derive Taylor expansions in limiting regimes and discuss the respective advantages and disadvantages of the iterative versus analytic approaches to solving the quartic.

LP 791-18 d is a temperate Earth-sized planet orbiting a late M dwarf, surrounded by an interior super-Earth (LP 791-18 b, $R_P$ = 1.2 $R_{\oplus}$, $P=0.95$ days) and an exterior sub-Neptune (LP 791-18 c, $R_P$ = 2.5 $R_{\oplus}$, $P=4.99$ days). Dynamical interactions between LP 791-18 d and c produce transit timing variations (TTVs) that can be used to constrain the planet masses and eccentricities. These interactions can also force a non-zero eccentricity for LP 791-18 d, which raises its internal temperature through tidal heating and could drive volcanic outgassing. We present three new transit observations of LP 791-18 c with Palomar/WIRC, including the most precise TTV measurements ($<$ 6 seconds) of this planet to date. We fit these times with a TTV model to obtain updated constraints on the mass, eccentricity, and tidal heat flux of LP 791-18 d. We reduce the mass uncertainty by more than a factor of two ($M_d$ = 0.91 $\pm$ 0.19 $M_{\oplus}$). We perform an updated fit assuming tidally damped free eccentricities and find $e_d = 0.0011^{+0.0010}_{-0.0008}$ and $e_c = 0.0001 \pm 0.0001$, consistent with circular orbits. We find that the observed TTVs are not sensitive to $e \leq$ $\sim$0.01. Without a tidally damped eccentricity prior, $e_d = 0.056^{+0.015}_{-0.014}$, much higher than the eccentricity predicted by n-body simulations incorporating the effects of dynamical excitation and tidal damping. We predict the timing of upcoming JWST secondary eclipse observations for LP 791-18 d, which could tightly constrain the eccentricity and tidal quality factor of this Earth-sized exoplanet.

Context. The circumnuclear disk (CND) is presently the main supply of mass for the accretion onto the supermassive black hole (SMBH) in the Galactic Center (GC). While the accretion is relatively slow, it has been suspected that local episodic explosive events play an important role in the temporary mass inflow toward the SMBH, while also affecting the evolution of the CND. Aims. The aim of this study is to follow the changes in mass flows caused by supernova (SN) explosions nestled in or near the CND. Methods. We perform simulations with the grid-based MHD code FLASH of the inner 5 pc of the Milky Way GC, including gravitational potential, rotation, magnetic field, central wind source, and the warm gas of the CND, all mimicking the observed physical properties. Results. Assuming a M$_\mathrm{SN}=10$ M$_\odot$ as the mass of the precursor of the core-collapse SN event at various locations within 2 pc from the GC, we detect a temporary increase in the accretion rate, transferring an additional 2-60 M$_\odot$ of warm gas to the immediate vicinity of the SMBH, depending on the explosion site. At the same time, the kinetic energy of the SN blows away even mass from the CND; the additional warm gas leaving the simulation domain after the explosion is on the order of $\sim100$ M$_\odot$. In the studied cases, the impact on mass flows and the turbulence caused by the explosion cease after $\sim250$ kyr.

Context: The recently discovered spherical eROSITA bubbles arise up to a latitude of $\pm$80°-85°in the X-ray regime of the Milky Way halo. Similar to the $\gamma$-ray Fermi bubbles, they evolve around the Galactic center, making a common origin plausible. However, the driving mechanism and evolution of both bubbles are still under debate. Aims: We want to investigate whether hydrodynamic energy injections at the Galactic center, such as e.g. tidal disruption events (TDEs), could have inflated both bubbles. The supermassive black hole Sagittarius A* is expected to tidally disrupt a star every 10-100 kyr, potentially leading to an outflow from the central region that drives a shock propagating into the Galactic halo due to its vertically declining density distribution, ultimately forming a superbubble blown out of the disk similar to the eROSITA and Fermi bubbles. Methods: We model TDEs in the Galaxy using three-dimensional hydrodynamical simulations, considering different Milky Way mass models and TDE rates. We then generate synthetic X-ray maps and compare them to observations. Results: Our simulation results of a $\beta$-model Milky Way halo show that superbubbles, blown for 16 Myr by regular energy injections at the Galactic center that occur every 100 kyr, can have a shape, shell stability, size, and evolution time similar to estimates for the eROSITA bubbles, and an overall structure reminiscent to the Fermi bubbles. The $\gamma$-rays in our model would stem from cosmic ray interactions at the contact discontinuity, where they were previously accelerated by first order Fermi acceleration at in situ shocks. Conclusions: Regular TDEs in the past 10-20 Myr near the Galactic center could have driven an outflow resulting in both, the X-ray emission of the eROSITA bubbles and the $\gamma$-ray emission of the Fermi bubbles.

The original Kepler mission has delivered unprecedented high-quality photometry. These data have impacted numerous research fields (e.g., asteroseismology and exoplanets), and continue to be an astrophysical goldmine. Because of this, thorough investigations of the ~ 200,000 stars observed by Kepler remain of paramount importance. In this paper, we present a state-of-the-art characterization of the Kepler targets based on Gaia DR3 data. We place the stars on the color-magnitude diagram (CMD), account for the effects of interstellar extinction, and classify targets into several CMD categories (dwarfs, subgiants, red giants, photometric binaries, and others). Additionally, we report various categories of candidate binary systems spanning a range of detection methods, such as Renormalised Unit Weight Error (RUWE), radial velocity variables, Gaia non-single stars (NSS), Kepler and Gaia eclipsing binaries from the literature, among others. First and foremost, our work can assist in the selection of stellar and exoplanet host samples regarding CMD and binary populations. We further complement our catalog by quantifying the impact that astrometric differences between Gaia data releases have on CMD location, assessing the contamination in asteroseismic targets with properties at odds with Gaia, and identifying stars flagged as photometrically variable by Gaia. We make our catalog publicly available as a resource to the community when researching the stars observed by Kepler.

Supermassive black holes (SMBH) are thought to grow through accretion of matter and mergers. Models of SMBH mergers have long suffered the final parsec problem, where SMBH binaries may stall before energy loss from gravitational waves (GW) becomes significant, leaving the pair unmerged. Direct evidence of coalesced SMBH remains elusive. Theory predicts that GW recoiling black holes can occur following a black hole merger. Here we present decisive spectroscopic evidence that the gas bound to the SMBH in the spatially offset quasar 3C 186 is blue-shifted relative to the host galaxy. This is exclusively explained by the GW recoil super-kick scenario. This confirmation of the ejection process implies that the final parsec problem is resolved in nature, providing evidence that even the most massive black holes can merge.

Protoplanetary discs, when externally irradiated by Far Ultraviolet (FUV) photons from OBA-type stars, lose material through photoevaporative winds, reducing the amount of material available to form planets. Understanding the link between environmental irradiation and observed disc properties requires accurately evaluating the FUV flux at star-hosting discs, which can be challenging due stellar parallax uncertainties. In this paper, we address this issue proposing a novel approach: using the local density distribution of a star-forming region (i.e. 2D pairwise star separations distribution) and assuming isotropy, we infer 3D separations between star-hosting discs and massive stars. We test this approach on synthetic clusters, showing that it significantly improves the accuracy compared to previous methods. We compute FUV fluxes for a large sample of star-bearing discs in 7 regions within 200 pc, 6 regions in Orion, and Serpens sub-regions, providing a publicly accessible catalogue. We find that discs in regions hosting late-type B and early-type A stars can reach non-negligible irradiation levels for disc evolution (10-100 G0). We investigate dust disc masses relative to FUV fluxes detecting hints of a negative correlation when restricting to average region ages. However, we emphasize the need for more stellar and disc measurements at >10^2 G0 to probe the dependence of disc properties on the environmental irradiation. Including average interstellar dust extinction, median FUV fluxes are not significantly attenuated, though this result may change if high-resolution 3D dust extinction maps were available. The method presented in this work is a powerful tool that can be expanded to additional regions.

The cosmic X-ray background (CXB) is dominated by the obscured and unobscured coronal light of active galactic nuclei (AGN). At energies below 10 keV, the CXB can be well explained by models taking into account the known AGN and the observed distribution of their obscuring, line-of-sight column densities, $N_{\rm H,l.o.s}$. However, at energies around the Compton reflection hump ($\sim30$ keV), the models fall short of the data. This suggests the existence of a population of as yet undetected Compton-thick AGN ($N_{\rm H,l.o.s}>1.5\times10^{24}$ cm$^{-2}$) whose X-ray spectra are dominated by the light that has been reprocessed by the obscuring material. In this work, we continue the effort to find and catalog all local ($z<0.05$) Compton-thick (CT) AGN. To this end, we obtained soft X-ray data with Chandra for six local BAT detected sources lacking ROSAT (0.1-2.4 keV) counterparts, indicating potential obscuration. We fit their spectra with Bayesian and least squares methods using two different models, borus02 and UXCLUMPY. We compare the results of the different models and methods and find that the $N_{\rm H,l.o.s}$ is consistently measured in each case. Three of the sources also were observed with XMM-Newton allowing the opportunity to search for variability in soft X-ray flux or $N_{\rm H,l.o.s}$. From this sample, we find one strong CT candidate (NGC 5759) and one weaker CT candidate (CGCG 1822.3+2053). Furthermore, we find tentative evidence of $N_{\rm H,l.o.s}$ variability in 2MASX J17253053-4510279, which has $N_{\rm H,l.o.s}<10^{22}$ cm$^{-2}$.

Carbon stars (with atmospheric C/O$>1$) range widely in temperature and luminosity, from low mass dwarfs to asymptotic giant branch stars (AGB). The main sequence dwarf carbon (dC) stars have inherited carbon-rich material from an AGB companion, which has since transitioned to a white dwarf. The dC stars are far more common than C giants, but no reliable estimates of dC space density have been published to date. We present results from an all-sky survey for carbon stars using the low-resolution XP spectra from Gaia DR3. We developed and measured a set of spectral indices contrasting C$_{\rm 2}$ and CN molecular band strengths in carbon stars against common absorption features found in normal (C/O$<1$) stars such as CaI, TiO and Balmer lines. We combined these indices with the XP spectral coefficients as input to supervised machine-learning algorithms trained on a vetted sample of known C stars from LAMOST. We describe the selection of the carbon candidate sample, and provide a catalog of 43,574 candidates dominated by cool C giants in the Magellanic Clouds and at low galactic latitude in the Milky Way. We report the confirmation of candidate C stars using intermediate ($R\sim 1800$) resolution optical spectroscopy from the Fred Lawrence Whipple Observatory, and provide estimates of sample purity and completeness. From a carefully-vetted sample of over 600 dCs, we measure their local space density to be $\rho_0\,=\,1.96^{+0.14}_{-0.12}\times10^{-6}\,\text{pc}^{-3}$ (about one dC in every local disk volume of radius 50\,pc), with a relatively large disk scale height of $H_z\,=\,856^{+49}_{-43}\,$pc.

We present new multi-wavelength observations of two ultraluminous X-ray sources (ULXs) hosted by globular clusters (GCs) in the giant elliptical NGC 1399, focusing on CXO J0338318-352604 (GCU7), only the second GC ULX known to have luminous optical emission lines. Notably, only NII and OIII emission is observed in the optical spectra, suggesting H-poor material. Previous work suggested the possibility that the properties of GCU7 could be explained by the tidal disruption of a horizontal branch star by an intermediate-mass black hole. We use new data to show that the lack of evolution in the X-ray or optical properties of the source over the last 20 years rules out this scenario. Instead, we use CLOUDY simulations to demonstrate that the optical emission lines are consistent with an outflow from an ultra-compact X-ray binary where a compact object - likely a neutron star (NS) - is accreting above the Eddington limit from a helium white dwarf (He WD). This binary would have dynamically formed from a direct collision between a NS and a red giant, or else via an exchange interaction. The ULX is predicted to evolve to lower mass transfer rates over time and eventually become a doppelganger to the well-studied ultra-compact X-ray binaries in Galactic GCs such as 4U 1820-30. These results show the utility of using extragalactic GCs to study short-lived phases in dynamical binary evolution that occur too rarely to be observed in Galactic clusters.

Context: Dark photons (Dph) appear in theories beyond the Standard Model of particles (SM). Under certain conditions, it is possible to have a mixing between SM photons and Dphs that should be observed as anomalies in the spectrum of astrophysical sources. Aim: To either find evidence of, or set constraints on the existence of Dphs with masses in the range of $\mu\text{eV}$ using observations of two galactic sources observed at TeV energies. Methods: Using the flux of the Crab Nebula and MGRO J1908+06 at TeV energies reported by HAWC and LHAASO observatories, and assuming a model where Dphs can mix with SM photons in the vacuum; we compute the Test Statistic (TS) to search for evidence of Dphs in the form of variations/attenuation in the observed spectrum. Results: We do not find statistically significant evidence of the existence of $\mu\text{eV}$ Dphs. Then, we compute the 68\% C.L. and 95\% C.L. exclusion regions for Dphs with masses in the range from $10^{-8}$ to $10^{-5}~\text{eV}$ and mixing angles with values between 0.01 and 1.0.

Oscillations between axion-like particles (ALPs) and photons in astrophysical magnetic fields can lead to irregularities in the high energy gamma ray spectra of blazars. The magnetic field within the blazar jet plays a crucial role in shaping these effects, with its strength in the emission region being an important parameter determined by multi-wavelength observations. However, the origin of the high energy bump observed in the spectral energy distribution of some blazars is a topic of debate, with both leptonic and hadronic scenarios providing plausible explanations that result in different magnetic field strengths in the emission region. In this study, we investigate the impact of magnetic field configurations on the constraints of ALP parameters. We consider both leptonic and hadronic emission scenarios for the blazar Mrk 501 and derive the corresponding jet magnetic field strengths. Additionally, we explore two jet magnetic field models: one with a toroidal component and the other with helical and tangled components. By analyzing the spectra of Mrk 501 observed by MAGIC and Fermi-LAT from 2017-06-17 to 2019-07-23, which are well-described by both emission scenarios, we derive constraints on the ALP parameters. Our results demonstrate that both the emission scenario and the magnetic field structure play a significant role in deriving these constraints, with the hadronic model leading to much more stringent limits compared to the leptonic model.

We discuss our transient search for directed energy systems in local galaxies, with calculations indicating the ability of modest searches to detect optical Search for Extraterrestrial Intelligence (SETI) sources in the closest galaxies. Our analysis follows Lubin (2016) where a messenger civilization follows a beacon strategy we call "intelligent targeting." We plot the required laser time to achieve an SNR of 10 and find the time for a blind transmission to target all stars in the Milky Way to be achievable for local galactic civilizations. As high cadence and sky coverage is the pathway to enable such a detection, we operate the Local Galactic Transient Survey (LGTS) targeting M31 (the Andromeda Galaxy), the Large Magellanic Cloud (LMC), and the Small Magellanic Cloud (SMC) via Las Cumbres Observatory's (LCO) network of 0.4 m telescopes. We explore the ability of modest searches like the LGTS to detect directed pulses in optical and near-infrared wavelengths from Extraterrestrial Intelligence (ETI) at these distances and conclude a civilization utilizing less powerful laser technology than we can construct in this century is readily detectable with the LGTS's observational capabilities. Data processing of 30,000 LGTS images spanning 5 years is in progress with the TRansient Image Processing Pipeline (TRIPP; Thomas et al. (2025)).

The Pierre Auger Observatory has conducted measurements of the energy spectrum and mass composition of cosmic rays using different methods. Utilizing both surface and fluorescence detectors (SD and FD), the Observatory provides unprecedented precision in understanding these particles. While primarily designed to measure ultra-high energy cosmic rays, the FD's high-elevation telescopes and the dense arrays of SD stations enable observations down to 6 PeV and 60 PeV, respectively. To determine the depth of shower maximum, a critical parameter for identifying primary particle types, both direct longitudinal profile measurements from the FD and indirect signal analyses from the SD are employed. An energy evolution of the mass of primary particles, as well as of the spectral index of the flux intensity, are observed and characterized by features described in the presented work. The measurements benefit from the joint operation of the FD and SD, delivering a systematic uncertainty of 14% in energy determination and an accumulated exposure reaching 80 000 km$^2$ sr yr at the highest energies.

We study in detail how massive galaxies accrete gas through cosmic time using cosmological hydrodynamical simulations from the High-z Evolution of Large and Luminous Objects (HELLO) and the Numerical Investigation of a Hundred Astrophysical Objects (NIHAO) projects. We find that accretion through cold filaments at high redshift (z ~ 2-4) is a key factor in maintaining the high star formation rates (> 100 Msun/yr) observed in these galaxies, and that more than 75% of the total gas participating in the star formation process is accreted via this channel at high z even in haloes well above 10^12 Msun. The low volume occupancy of the filaments allows plenty of space for massive gas outflows generated by the vigorous star formation and AGN activity, with the cold incoming gas and the hot outflowing gas barely interacting. We present a model based on a Bayesian hierarchical formalism that accurately describes the evolution of the cold fraction accretion with redshift and halo mass. Our model predicts a relatively constant critical mass (Mc) for the cold-to-hot transition up to z ~ 1.3 and an evolving critical mass log(Mc) proportional to log(1+z)^1.7 at higher redshift. Overall, our findings provide deeper insight into the cosmic evolution of gas accretion modes and offer a robust framework for understanding how cold accretion contributes to galaxy growth across different epochs.

Cepheid circumstellar emissions have previously been detected via both infrared excess and infrared interferometric observations at a few stellar radii. Those studies have shown that these circumstellar emission can be produced by ionized gas, however there is no direct observational evidence to confirm this hypothesis. In this letter we explore the continuum emission and a spectrum of the bright and long-period Cepheid, $\ell$~Car ($P=35.56\,$day) at millimeter-wavelengths in order to detect possible effects of ionized gas emission. We presented ALMA observations of $\ell$ Car in two spectral setups in Band~6 (near 212 and 253\,GHz, respectively) and we compared the measured flux density to one expected for the stellar continuum. We also derived the spectral index and probed the presence of Radio Recombination Lines (RRL). We report statistically significant emission of about 3.5$\,$mJy in the two spectral ranges, which is about 2.5 times the stellar continuum emission. For the first time, we are also able to derive the spectral index of the flux density ($S_\nu \propto \nu^\alpha$), $\alpha=+1.26\pm$0.44 ($\sim$3$\sigma$ error), which is characteristic of partially optically thick ionized gas emission. Additionally, we discovered an emission line from a RRL of hydrogen H29$\alpha$ centered on the stellar rest velocity, smaller in spatial extent than about 0\farcs2 ($\lesssim 100\,$AU), with a symmetric profile with a width at half power of 55.3$\pm$7.5\,\kms (1$\sigma$ error). It confirms the presence of ionized gas emission near $\ell$~Car. The millimeter emission detected from $\ell$ Car can be attributed to ionized gas emission from the Cepheid's chromosphere. Further radio interferometric observations are necessary to confirm the occurrence of these ionized gas envelopes around Cepheids of different pulsation periods.

Several processes in the Universe convert a fraction of gas kinetic energy into the acceleration of relativistic electrons, making them observable at radio wavelengths, or contributing to a dormant reservoir of low-energy cosmic rays in cosmic structures. We present a new suite of cosmological simulations, with simple galaxy formation models calibrated to work at a specific spatial resolution, tailored to study all most important processes of injection of relativistic electrons in evolving large-sale structures: accretion and merger shocks, feedback from active galactic nuclei and winds from star forming regions. We also follow the injection of magnetic fields by active galactic nuclei and star formation, and compute the observational signatures of these mechanisms. We find that the injection of cosmic ray electrons by shocks is the most volume filling process, and that it also dominates the energy density of fossil relativistic electrons in halos. The combination of the seeding mechanisms studied in this work, regardless of the uncertainties related to physical or numerical uncertainties, is more than enough to fuel large-scale radio emissions with a large amount of seed fossil electrons. We derive an approximated formula to predict the number of fossil cosmic ray electrons injected by z=0 by the total activity of shocks, AGN and star formation in the volume of halos. By looking at the maximum possible contribution to the magnetisation of the cosmic web by all our simulated sources, we conclude that galaxy formation-related processes, alone, cannot explain the values of Faraday Rotation of background polarised sources recently detected using LOFAR.

We perform fully general-relativistic hydrodynamics simulations of binary neutron star mergers over $100\,\rm ms$ post-merger to investigate the dynamics of remnant massive neutron stars (NSs). Our focus is mainly on the analysis of convective stability and mode characteristics of the massive NSs. We derive stability criteria for hot, differentially rotating relativistic stars that account for both buoyant and rotational restoring forces, and apply them for the first time to the post-merger massive NSs. Our results show no evidence of large-scale convective instability, as both angle-averaged specific entropy and specific angular momentum increase outward within the massive NSs. Rotational effects significantly enhance stability for local regions that would be otherwise unstable by the Schwarzschild criterion. Additionally, our mode analysis of matter fields and gravitational waves reveals no excitation of inertial modes after the damping of quadrupolar $f$-modes in the massive NSs, contrasting with previous studies. As in many previous works, we observe the excitation of an $m=1$ one-armed mode. However, we also find that the growth of the $m=1$ mode amplitude after the merger may correlate strongly with the violation of linear momentum conservation, indicating that we cannot reject the possibility that the excitation of the one-armed mode has a numerical origin.

The purpose of this paper is to review the most popular deep learning methods used to analyze astroparticle data obtained with Imaging Atmospheric Cherenkov Telescopes and provide references to the original papers.

The number of known planets around intermediate-mass stars (1.5 M$_{\odot}$ < M$_{\star}$ < 3.5 M$_{\odot}$) is rather low. We aim to test whether the correlation between the metallicity of the star and the presence of gas-giant planets found for MS low-mass stars still holds for intermediate-mass stars. In particular, we aim to understand whether or not the planet-metallicity relation changes as stars evolve from the pre-MS to the red giant branch. Our results confirm that pre-MS stars with transitional discs with gaps show lower metallicities than pre-MS with flat discs. We show a tendency of intermediate-mass stars in the MS to follow the gas-giant planet-metallicity correlation, although the differences in metal content between planet and non-planet hosts are rather modest and the strength of the correlation is significantly lower than for the less massive FGK MS stars. For stars in the red giant branch, we find a strong planet-metallicity correlation, compatible with that found for FGK MS stars. We discuss how the evolution of the mass in the convective zone of the star's interior might affect the measured metallicity of the star. The lack of a well-established planet-metallicity correlation in pre-MS and MS intermediate-mass stars can be explained by a scenario in which planet formation leads to an accretion of metal-poor material on the surface of the star. As intermediate-mass stars are mainly radiative the metallicity of the star does not reflect its bulk composition but the composition of the accreted material. When the star leaves the MS and develops a sizeable convective envelope, a strong-planet metallicity correlation is recovered. Thus, our results are in line with core-accretion models of planet formation and the idea that the planet-metallicity correlation reflects a bulk property of the star.

We report the Australian Telescope Compact Array and Nobeyama 45 m telescope detection of a remarkably bright $S_\mathrm{1.1mm}$ = 44 mJy) submillimeter galaxy MM J154506.4-344318 in emission lines at 48.5 and 97.0 GHz, respectively. We also identify part of an emission line at $\approx$ 218.3 GHz using the Atacama Large Millimeter/submillimeter Array (ALMA). Together with photometric redshift estimates and the ratio between the line and infrared luminosities, we conclude that the emission lines are most likely to be the $J$ = 2-1, 4-3, and 9-8 transitions of $^{12}$CO at redshift $z = 3.753 \pm 0.001$. ALMA 1.3 mm continuum imaging reveals an arc and a spot separated by an angular distance of 1.6 arcsec, indicative of a strongly-lensed dusty star-forming galaxy with respective molecular and dust masses of $\log{M_{\rm mol}/M_\odot} \approx 11.5$ and $\log{M_{\rm dust}/M_\odot} \approx 9.4$ after corrected for $\approx$ 6.6$\times$ gravitational magnification. The inferred dust-to-gas mass ratio is found to be high ($\approx$ 0.0083) among coeval dusty star-forming galaxies, implying the presence of a massive, chemically-enriched reservoir of cool interstellar medium at $z \approx 4$ or 1.6 Gyr after the Big Bang.

The first few hours of a supernova contain significant information about the progenitor system. The most modern wide-field surveys that scan the sky repeatedly every few days can discover all kinds of transients in those early epochs. At such times, some progenitor footprints may be visible, elucidating critical explosion parameters and helping to distinguish between leading explosion models. A dedicated spectroscopic classification programme using the optical spectrograph OSIRIS mounted to the Gran Telescopio de Canarias was set up to try to obtain observations of supernova at those early epochs. With the time awarded, we obtained spectra for 10 SN candidates, which we present here. Half of them were thermonuclear SNe, while the other half were core-collapse SNe. Most (70\%) were observed within the first six days of the estimated explosion, with two being captured within the first 48 hours. We present a characterization of the spectra, together with other public ancillary photometry from ZTF and ATLAS. This programme shows the need for an accompanying rapid-response spectroscopic programme to existing and future deep photometric wide-field surveys located at the right longitude to be able to trigger observations in a few hours after the discovery of the supernova candidate. Both the future La Silla Southern Supernova Survey (LS4) and the Legacy Survey of Space and Time (LSST) both located in Chile will be providing discovery and follow up of most of the transients in the southern hemisphere. This paper demonstrates that with a rapid spectroscopic programme and stringent triggering criteria, obtaining a sample of SN with spectra within a day of the explosion is possible.

The weak gravitational lensing magnification of Type Ia supernovae (SNe Ia) is sensitive to the matter power spectrum on scales $k>1 h$ Mpc$^{-1}$, making it unwise to interpret SNe Ia lensing in terms of power on linear scales. We compute the probability density function of SNe Ia magnification as a function of standard cosmological parameters, plus an empirical parameter $A_{\rm mod}$ which describes the suppression or enhancement of matter power on non-linear scales compared to a cold dark matter only model. While baryons are expected to enhance power on the scales relevant to SN Ia lensing, other physics such as neutrino masses or non-standard dark matter may suppress power. Using the Dark Energy Survey Year-5 sample, we find $A_{\rm mod} = 0.77^{+0.69}_{-0.40}$ (68\% credible interval around the median). Although the median is consistent with unity there are hints of power suppression, with $A_{\rm mod} < 1.09$ at 68\% credibility.

There is an intricate relationship between the organization of large-scale magnetic fields by a stellar dynamo and the rate of angular momentum loss due to magnetized stellar winds. An essential ingredient for the operation of a large-scale dynamo is the Coriolis force, which imprints organizing flows on the global convective patterns and inhibits the complete cancellation of bipolar magnetic regions. Consequently, it is natural to expect a rotational threshold for large-scale dynamo action and for the efficient angular momentum loss that it mediates through magnetic braking. Here we present new observational constraints on magnetic braking for an evolutionary sequence of six early K-type stars. To determine the wind braking torque for each of our targets, we combine spectropolarimetric constraints on the large-scale magnetic field, Ly-alpha or X-ray constraints on the mass-loss rate, as well as uniform estimates of the stellar rotation period, mass, and radius. As identified previously from similar observations of hotter stars, we find that the wind braking torque decreases abruptly by more than an order of magnitude at a critical value of the stellar Rossby number. Given that all of the stars in our sample exhibit clear activity cycles, we suggest that weakened magnetic braking may coincide with the operation of a subcritical stellar dynamo.

There has been recent interest in the cosmological consequences of energy-momentum-powered gravity models, in which the matter side of Einstein's equations includes a term proportional to some power, $n$, of the energy-momentum tensor, in addition to the canonical linear term. Previous works have suggested that these models can lead to a recent accelerating universe without a cosmological constant, but they can also be seen as phenomenological extensions of the standard $\Lambda$CDM, which are observationally constrained to be close to the $\Lambda$CDM limit. Here we show that these models violate the temperature-redshift relation, and are therefore further constrained by astrophysical measurements of the cosmic microwave background temperature. We provide joint constraints on these models from the combination of astrophysical and background cosmological data, showing that this power is constrained to be about $|n|<0.01$ and $|n|<0.1$, respectively in models without and with a cosmological constant, and improving previous constraints on this parameter by more than a factor of three. By breaking degeneracies between this parameter and the matter density, constraints on the latter are also improved by a factor of about two.

Young low-mass protostars often possess hot corinos, compact, hot and dense regions bright in interstellar Complex Organic Molecules (iCOMs). Besides of their prebiotic role, iCOMs can be used as a powerful tool to characterize the chemical and physical properties of hot corinos. Using ALMA/FAUST data we aim to explore the iCOMs emission at < 50 au scale around the Class 0 prototypical hot corino IRAS 4A2. We imaged IRAS 4A2 in six abundant, common iCOMs (CH$_3$OH, HCOOCH$_3$, CH$_3$CHO, CH$_3$CH$_2$OH, CH$_2$OHCHO, and NH$_2$CHO), and derived their emitting size. The column density and gas temperature for each species were derived at 1$\sigma$ from a multi-line analysis by applying a non-LTE approach for CH$_3$OH, and LTE population or rotational diagram analysis for the other iCOMs. Thanks to the unique estimates of the absorption from foreground millimeter dust toward IRAS 4A2, we derived for the first time unbiased gas temperatures and column densities. We resolved the IRAS 4A2 hot corino finding evidence for a chemical spatial distribution in the inner 50 au, with the outer emitting radius increasing from ~ 22-23 au for NH$_2$CHO and CH$_2$OHCHO, followed by CH$_3$CH$_2$OH (~ 27 au), CH$_3$CHO (~ 28 au), HCOOCH$_3$ (~ 36 au), and out to ~ 40 au for CH$_3$OH. Combining our estimate of the gas temperature probed by each iCOM with their beam-deconvolved emission sizes, we inferred the gas temperature profile of the hot corino on scales of 20-50 au in radius, finding a power-law index $q$ of approximately -1. We observed, for the first time, a chemical segregation in iCOMs of the IRAS 4A2 hot corino, and derived the gas temperature profile of its inner envelope. The derived profile is steeper than when considering a simple spherical collapsing and optically-thin envelope, hinting at a partially optically-thick envelope or a gravitationally unstable disk-like structure.

For a precise determination of cosmological parameters we need to understand the effects of the local large-scale structure of the Universe on the measurements. They include modifications of the cosmic microwave background, distortions of sky images by large-scale gravitational lensing, and the influence of large-scale streaming motions on measurements of the Hubble constant. The streaming motions, for example, originate from mass concentrations with distances up to 250 Mpc. In this paper we provide the first all-sky assessment of the largest structures at distances between 130 and 250 Mpc and discuss their observational consequences, using X-ray galaxy clusters to map the matter density distribution. Among the five most prominent superstructures found, the largest has a length longer than 400 Mpc with an estimated mass of about 2 10e17 Msun. This entity, which we named Quipu, is the largest cosmic structure discovered to date. These superstructures contain about 45% of the galaxy clusters, 30% of the galaxies, 25% of the matter, and occupy a volume fraction of 13%, thus constituting a major part of the Universe. The galaxy density is enhanced in the environment of superstructures out to larger distances from the nearest member clusters compared to the outskirts of clusters in the field. We find superstructures with similar properties in simulations based on Lambda-CDM cosmology models. We show that the superstructures should produce a modification on the cosmic microwave background through the integrated Sachs-Wolf effect. Searching for this effect in the Planck data we found a signal of the expected strength, however, with low significance. Characterising these superstructures is also important for astrophysical research, for example the study of the environmental dependence of galaxy evolution as well as for precision tests of cosmological models.

The interplay between stellar multiplicity and protoplanetary discs represents a cornerstone of modern astrophysics, offering key insights into the processes of planet formation. Protoplanetary discs act as cradles for planetary systems, yet their evolution and capacity to form planets are profoundly affected by gravitational forces within multiple stellar systems. This review synthesises recent advancements in observational and theoretical studies to explore the rich diversity of circumstellar and circumbinary discs within multiple stellar systems. We examine how stellar companions shape disc morphology through truncation, spirals, and misalignment. We also outline how dust dynamics and planetesimal formation are impacted by stellar multiplicity. On top of this, observations at high angular resolution reveal detailed disc structures, while simulations offer key insights into their evolution. Last, we consider the implications of stellar multiplicity for planetary system architectures, emphasising the diversity of planetary outcomes in such environments. Looking ahead, coordinated efforts combining high-resolution observations with advanced numerical models will be critical for unravelling the role of multiple stellar systems in shaping planetary formation and evolution.

We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape fractions. Using a sample of 268 spectroscopically confirmed background galaxies at 2.7<z<3.0 and a galaxy density map at z~2.5 within the COSMOS field, we measure the Lya transmission photometrically, leveraging the multiwavelength data available from the COSMOS2020 catalog. Our results reveal a weak but statistically significant positive correlation between Lya optical depth and galaxy density contrast, suggesting that overdense regions are enriched in neutral gas, which could bias escape fraction measurements. This emphasizes the need to account for the large-scale structure of the IGM in analyses of ionizing radiation escape fractions, and highlights the advantages of a photometric approach for increasing the number of sampled lines of sight across large fields. The photometric redshifts provided by upcoming all-sky surveys, such as Euclid, will make it possible to account for this effect across widely separated fields.

Kilonova is an optical-infrared transient powered by the radioactive decay of heavy nuclei from binary neutron star mergers. Its observational characteristics depend on the mass and the nuclide composition of meger ejecta, which are sensitive to the equation of state (EoS) of neutron star. We use astrophysical conditions derived from different EoSs as nucleosynthesis inputs to explore the impact of various EoS on the $r$-process nucleosynthesis and the kilonova emission. Our results show that both the abundance patterns of merger ejecta and kilonova light curves are strongly dependent on the neutron star EoSs. Given the mass of two neutron stars, the merger with a softer EoS tends to generate a larger amount of ejected material, and may lead to a brighter kilonova peak luminosity. The relationship between the neutron star EoS and the peak luminosity provides a probe for constraining the properties of EoS in multi-messenger observations of neutron star mergers.

Various phenomena of physics beyond that of the Standard Model could occur at high scale. Ultra-high energy cosmic rays are the only particles available to explore scales above a few dozens of TeV. Although these explorations are much more limited than those carried out with colliders, they provide a series of constraints in several topics such as tests of Lorentz invariance, dark matter, phase transitions in the early universe or sterile neutrinos. Several of these constraints are reviewed in these proceedings of UHECR2024 based on searches for anomalous characteristics in extensive air showers or searches for ultra-high energy gamma rays and neutrinos.

Submillimeter galaxies (SMGs) constitute a key population of bright star-forming galaxies at high redshift. These galaxies challenge galaxy formation models, particularly in reproducing their observed number counts and redshift distributions. Furthermore, although SMGs contribute significantly to the cosmic star formation rate density (SFRD), their precise role remains uncertain. Upcoming surveys, such as the Ultra Deep Survey with the TolTEC camera, are expected to offer valuable insights into SMG properties and their broader impact. Robust modeling of SMGs in a cosmologically representative volume is necessary to investigate their nature in preparation for next-generation submillimeter surveys. We implement and test parametric relations derived from radiative transfer calculations across three cosmological simulations: EAGLE, IllustrisTNG, and FLAMINGO. Particular emphasis is placed on the FLAMINGO due to their large volume and robust statistical sampling of SMGs. Based on the model that best reproduces observations, we forecast submillimeter fluxes within the simulations, analyze the properties of SMGs, and evaluate their evolution over cosmic time. Our results show that the FLAMINGO reproduces the observed redshift distribution and source number counts of SMGs without requiring a top-heavy initial mass function. On the other hand, the EAGLE and IllustrisTNG show a deficit of bright SMGs. We find that SMGs with S850 > 1 mJy contribute up to 27% of the SFRD at z=2.6 in the FLAMINGO, consistent with recent observations. Flux density functions reveal a rise in SMG abundance from z = 6 to 2.5, followed by a sharp decline in the number of brighter SMGs from z = 2.5 to 0. Leveraging the SMG population in FLAMINGO, we forecast that the TolTEC UDS will detect 80,000 sources over 0.8 deg^2 at 1.1 mm (at the 4{\sigma} detection limit), capturing about 50% of the cosmic SFRD at z=2.5.

The Quick Ultra-Violet Kilonova surveyor (QUVIK), a two-band UV space telescope approved for funding as a Czech national science and technology mission, will focus on detecting early UV light of kilonovae (Werner et al., 2024). In addition, it will study the UV emission of stars and stellar systems (Krtička et al., 2024) as well as the intense and variable emission of active galactic nuclei (AGN) or galactic nuclei activated by tidal disruption events (Zajaček et al., 2024). In this contribution, we describe the role of this small ($\sim 30$-cm diameter) UV telescope for studying bright, nearby AGN. With its NUV and FUV bands, the telescope will perform high-cadence ($\sim$ 0.1-1 day) two-band photometric monitoring of nearby AGN ($z<1$), which will allow us to probe accretion disk sizes/temperature profiles via photometric reverberation mapping. Thanks to its versatility, QUVIK will be able to perform a moderately fast repointing ($<20$ min) to target candidates for tidal disruption events (TDEs). Early detection of the UV emission following a TDE optical flare, in combination with the subsequent two-band UV monitoring performed simultaneously with other observatories, will enable us to infer the time delay (or its lack of) between the optical, UV, and X-ray emission. In combination with theoretical models, it will be possible to shed more light on the origin of the UV/optical emission of TDEs. Furthermore, the two-band monitoring of nuclear transients will be beneficial in distinguishing between TDEs (nearly constant blue colour) and supernovae (progressive reddening).

We investigate the dust mass build-up and star formation efficiency of two galaxies at $z>12$, GHZ2 and GS-z14-0, by combining ALMA and JWST observations with an analytical model that assumes dust at thermal equilibrium. We obtained $3\sigma$ constraints on dust mass of $\log M_{\rm dust}/M_{\odot}<5.0$ and $<5.3$, respectively. These constraints are in tension with a high dust condensation efficiency in stellar ejecta but are consistent with models with a short metal accretion timescale at $z>12$. Given the young stellar ages of these galaxies ($t_{\rm age}\sim10\,{\rm Myrs}$), dust grain growth via accretion may still be ineffective at this stage, though it likely works efficiently to produce significant dust in galaxies at $z\sim7$. The star formation efficiencies, defined as the SFR divided by molecular gas mass, reach $\sim10\,{\rm Gyr}^{-1}$ in a 10\,Myr timescale, aligning with the expected redshift evolution of `starburst' galaxies with efficiencies that are $\sim0.5$--$1\,{\rm dex}$ higher than those in main-sequence galaxies. This starburst phase seems to be common in UV-bright galaxies at $z>12$ and is likely associated with the unique conditions of the early phases of galaxy formation, such as bursty star formation and/or negligible feedback from super-Eddington accretion. Direct observations of molecular gas tracers like [C\,{\sc ii}] will be crucial to further understanding the nature of bright galaxies at $z>12$.

We introduce a prescription for estimating the flux of the 7.7 micron and 11.3 micron\ polycyclic aromatic hydrocarbon (PAH) features from broadband JWST/MIRI images. Probing PAH flux with MIRI imaging data has advantages in field of view, spatial resolution, and sensitivity compared with MIRI spectral maps, but comparisons with spectra are needed to calibrate these flux estimations over a wide variety of environments. For 267 MIRI/MRS spectra from independent regions in the four luminous infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey (GOALS) early release science program, we derive synthetic filter photometry and directly compare estimated PAH fluxes to those measured from detailed spectral fits. We find that for probing PAH 7.7 micron, the best combination of filters is F560W, F770W, and either F1500W or F2100W, and the best for PAH 11.3 micron is F560W, F1000W, F1130W, and F1500W. The prescription with these combinations yields predicted flux densities that typically agree with values from spectral decomposition within ~7% and ~5% for PAH 7.7 and 11.3 micron, respectively.

It has recently been revealed [R. Gervalle and M. S. Volkov, Phys. Rev. Lett. (2024)] that magnetically charged black holes of the composed Einstein-Weinberg-Salam field theory can support bound-state hairy configurations of electroweak fields. In the present paper we study, using {\it analytical} techniques, the physical and mathematical properties of the supported linearized electroweak fields (spatially regular electroweak 'clouds') in the dimensionless large-mass $\mu\equiv m_{\text{w}} r_+\gg1$ regime of the composed black-hole-field system (here $m_{\text{w}}$ is the mass of the supported W-boson field and $r_+$ is the outer horizon radius of the central supporting black hole). In particular, we derive a remarkably compact formula for the discrete resonance spectrum $\{\mu_k(n)\}_{k=0}^{k=\infty}$ that characterizes the composed black-hole-linearized-field configurations, where the integer $n\equiv 2Pe\in\mathbb{Z}$ characterizes the discrete charge parameter $P$ of the central magnetic Reissner-Nordström black hole and $e$ is the electron charge. The physical significance of the analytically derived resonant spectrum stems from the fact that, in the dimensionless large-charge $n\gg1$ regime, the fundamental (largest) eigenvalue $\mu_0(n)$ determines the critical existence-line of the composed Einstein-Weinberg-Salam theory, a boundary line that separates hairy magnetic-black-hole-electroweak-field bound-state configurations from bald magnetic Reissner-Nordström black holes.

The lifetime of free neutrons measured in the lab has a long standing disparity of $\sim$9~s. A space-based technique has recently been proposed to independently measure the neutron lifetime using interactions between the galactic cosmic rays and a low atmosphere planetary body. This technique has not produced competitive results yet due to constraints of non-optimized data that contain large systematic errors. We use data from the neutron spectrometer on-board NASA's Lunar Prospector, and quantify the effects of lunar sub-surface temperature and the composition on the measurement of neutron lifetime. We use the HeCd and HeSn neutron spectrometer data when the spacecraft was in a highly elliptical orbit during the orbit insertion period. We report the neutron lifetime using lunar composition maps at different resolutions: 5$^{\circ}$ Prettyman+2006 and 2$^{\circ}$ re-binned Wilson+2021 maps to be 777.59$\pm$11.71~s and 739.64$\pm$10.83~s respectively. Further, for the 20$^{\circ}$ map, we apply both a constant equatorial and a latitude-dependent temperature model and report 738.63$\pm$10.75~s and 767.33$\pm$11.17~s respectively. We report the weighted average of the four measurements to be $\tau_n = 754.72 ^{+34.58}_{-25.91}$~s.

The physics of particle acceleration in turbulent plasmas is a topic of broad interest, which is making rapid progress thanks to dedicated, large-scale numerical experiments. The first part of this paper presents an effective theory of stochastic Fermi acceleration, which subsumes all forms of non-resonant acceleration in ideal electric fields and is applicable in generic settings. It combines an exact equation connecting the energization rate to the statistics of the velocity field with a statistical model of particle transport through the structures (i.e., the regions of strong velocity gradients). In a second part, this formalism is applied to MHD turbulence to obtain a comprehensive assessment of the scale-by-scale contributions to the advection and diffusion coefficients. Acceleration is found to be maximal on scales where particles can be trapped inside structures for an eddy turn-around timescale, or in intense structures associated with sharp bends of the magnetic field lines in large-amplitude turbulence (as reported earlier). These fast acceleration regimes, which are inhomogeneous in space, pave the way for a rich phenomenology. We discuss the scalings obtained, their interpretation and show that the findings compare satisfactorily with existing numerical results.

In this work, we study the propagation and spin oscillations of neutrinos in their scattering by a supermassive black hole (SMBH) surrounded by a realistic accretion disk. We use a semi-analytical model of a thick accretion disk which can co-rotate and counter-rotate with respect to BH. Moreover, we assume that a disk contains only a toroidal magnetic magnetic field of moderate strength. Spin precession of neutrinos, which are supposed to be Dirac particles, is caused by the interaction of the neutrino magnetic moment with the magnetic field in the disk. We consider the incoming flux of neutrinos having an arbitrary angle with respect to the BH spin since the recent results of the Event Horizon Telescope indicate that the BH spin in the galactic center is not always perpendicular to the galactic plane. For our study, we consider a large number of incoming test neutrinos. We briefly discuss our results and their applications in the observations of astrophysical neutrinos.