Papers for Friday, Feb 02 2024

The outer areas of Jupiter and Saturn have multiple zonal winds, reaching the high latitudes, that penetrate deep into the planets' interiors, as suggested by gravity measurements. These characteristics are replicable in numerical simulations by including both a shallow stably stratified layer, below a convecting envelope, and increasing electrical conductivity. A dipolar magnetic field, assumed to be generated by a dynamo below our model, is imposed. We find that the winds' depth into the stratified layer depends on the local product of the squared magnetic field strength and electrical conductivity. The key for the drop-off of the zonal winds is a meridional circulation which perturbs the density structure in the stable layer. In the stable region its dynamics is governed by a balance between Coriolis and electromagnetic forces. Our models suggest that a stable layer extending into weakly conducting regions could account for the observed deep zonal wind structures.

Compact massive relic galaxies are a class of galaxies that exhibit characteristics suggesting they have remained largely unchanged since their initial formation, making them 'relics' of the early universe. These galaxies represent a distinct class characterized by strongly peaked high-velocity dispersion profiles with large rotational velocities. This study investigates the formation of such galaxies within the framework of Milgromian Dynamics (MOND), offering a unique perspective on their origin without invoking the presence of cold or warm dark matter. Our analysis focuses on the collapse dynamics of isolated non-rotating post-Big-Bang gas clouds, revealing kinematic and density profiles comparable to observed compact massive relic galaxies like NGC 1277, Mrk 1216, and PGC 032873. The findings underscore the natural emergence of compact massive relic galaxies within a MOND-based Universe, providing valuable insights into the interplay between gravitational dynamics and galaxy formation.

Blue Horizontal Branch (BHB) stars, excellent distant tracers for probing the Milky Way's halo density profile, are distinguished in the $(g-r)_0$ vs $(i-z)_0$ color space from another class of stars, blue straggler stars (BSs). We develop a Bayesian mixture model to classify BHB stars using high-precision photometry data from the Dark Energy Survey Data Release 2 (DES DR2). We select $\sim2100$ highly-probable BHBs based on their $griz$ photometry and the associated uncertainties, and use these stars to map the stellar halo over the Galactocentric radial range $20 \lesssim R \lesssim 70$ kpc. After excluding known stellar overdensities, we find that the number density $n_\star$ of BHBs can be represented by a power law density profile $n_\star \propto R^{-\alpha}$ with an index of $\alpha=4.28_{-0.12}^{+0.13}$, consistent with existing literature values. In addition, we examine the impact of systematic errors and the spatial inhomogeneity on the fitted density profile. Our work demonstrates the effectiveness of high-precision $griz$ photometry in selecting BHB stars. The upcoming photometric survey from the Rubin Observatory, expected to reach depths 2-3 magnitudes greater than DES during its 10-year mission, will enable us to investigate the density profile of the Milky Way's halo out to the virial radius, unravelling the complex processes of formation and evolution in our Galaxy.

This paper presents a machine learning-based method for the detection of the unique gravitational microlensing signatures of extended dark objects, such as boson stars, axion miniclusters and subhalos. We adapt MicroLIA, a machine learning-based package tailored to handle the challenges posed by low-cadence data in microlensing surveys. Using realistic observational timestamps, our models are trained on simulated light curves to distinguish between microlensing by point-like and extended lenses, as well as from other object classes which give a variable magnitude. We show that boson stars, examples of objects with a relatively flat mass distribution, can be confidently identified for $0.8 \lesssim r/r_E\lesssim 3$. Intriguingly, we also find that more sharply peaked structures, such as NFW-subhalos, can be distinctly recognized from point-lenses under regular observation cadence. Our findings significantly advance the potential of microlensing data in uncovering the elusive nature of extended dark objects. The code and dataset used are also provided.

The escape velocity profile of the Milky Way offers a crucial and independent measurement of its underlying mass distribution and dark matter properties. Using a sample of stars from Gaia DR3 with 6D kinematics and strict quality cuts, we obtain an escape velocity profile of the Milky Way from 4 kpc to 11 kpc in Galactocentric radius. To infer the escape velocity in radial bins, we model the tail of the stellar speed distribution with both traditional power law models and a new functional form that we introduce. While power law models tend to rely on extrapolation to high speeds, we find our new functional form gives the most faithful representation of the observed distribution. Using this for the escape velocity profile, we constrain the properties of the Milky Way's dark matter halo modeled as a Navarro-Frenck-White profile. Combined with constraints from the circular velocity at the solar position, we obtain a concentration and mass of $c_{200\rm{c}}^{\rm{DM}} = 13.9^{+6.2}_{-4.3}$ and $\rm{M}_{200\rm{c}}^{\rm{DM}} = 0.55^{+0.15}_{-0.14}\times 10^{12} M_\odot$. This corresponds to a total Milky Way mass of $\rm{M}_{200\rm{c}} = 0.64^{+0.15}_{-0.14}\times 10^{12} M_\odot$, which is on the low end of the historic range of the Galaxy's mass, but in line with other recent estimates.

In this work, we study the AGN radio detection effectiveness in the major deep extragalactic surveys, considering different AGN obscuration levels, redshift, and AGN bolometric luminosities. We particularly focus on comparing their radio and X-ray detectability, making predictions for present and future radio surveys. We extrapolate the predictions of AGN population synthesis model of cosmic X-ray background (CXB) to the radio band, by deriving the 1.4 GHz luminosity functions of unobscured (i.e. with hydrogen column densities $\log N_{H} <22$), obscured ($22<\log N_{H}<24$) and Compton-thick (CTK, $\log N_{H} >24$) AGN. We then use these functions to forecast the number of detectable AGN based on the area, flux limit, and completeness of a given radio survey and compare it with the AGN number resulting from X-ray predictions. When applied to deep extragalactic fields covered both by radio and X-ray observations, we show that, while X-ray selection is generally more effective in detecting unobscured AGN, the surface density of CTK AGN radio detected is on average $\sim 10$ times larger than the X-ray one, and even greater at high redshifts, considering the current surveys and facilities. Our results suggest that thousands of CTK AGN are already present in current radio catalogs, but most of them escaped any detection in the corresponding X-ray observations. We also present expectations for the number of AGN to be detected by the Square Kilometer Array Observatory (SKAO) in its future deep and wide radio continuum surveys, finding that it will be able to detect more than 2000 AGN at $z>6$ and some tens at $z>10$, more than half of which are expected to be CTK.

Upcoming cosmic shear analyses will precisely measure the cosmic matter distribution at low redshifts. At these redshifts, the matter distribution is affected by galaxy formation physics, primarily baryonic feedback from star formation and active galactic nuclei. Employing measurements from the Magneticum and IllustrisTNG simulations and a dark matter + baryon (DMB) halo model, this paper demonstrates that Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters, whose masses have been calibrated using weak gravitational lensing, can constrain the baryonic impact on cosmic shear with statistical and systematic errors subdominant to the measurement errors of DES-Y3 and LSST-Y1. We further dissect the contributions from different scales and halos with different masses to cosmic shear, highlighting the dominant role of SZ clusters at scales critical for cosmic shear analyses. These findings suggest a promising avenue for future joint analyses of Cosmic Microwave Background (CMB) and lensing surveys.

We characterize the multiphase circumgalactic medium and galaxy properties at z = 6.0-6.5 in four quasar fields from the James Webb Space Telescope A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE) program. We use the Very Large Telescope/X-shooter spectra of quasar J0305-3150 to identify one new metal absorber at z = 6.2713 with multiple transitions (OI, MgI, FeII and CII). They are combined with the published absorbing systems in Davies et al. (2023a) at the same redshift range to form of a sample of nine metal absorbers at z = 6.03 to 6.49. We identify eight galaxies within 1000 km s$^{-1}$ and 350 kpc around the absorbing gas from the ASPIRE spectroscopic data, with their redshifts secured by [OIII]($\lambda\lambda$4959, 5007) doublets and H$\beta$ emission lines. Our spectral energy distribution fitting indicates that the absorbing galaxies have stellar mass ranging from 10$^{7.2}$ to 10$^{8.8}M_{\odot}$ and metallicity between 0.02 and 0.4 solar. Notably, the z = 6.2713 system in the J0305-3150 field resides in a galaxy overdensity region, which contains two (tentatively) merging galaxies within 350 kpc and seven galaxies within 1 Mpc. We measure the relative abundances of $\alpha$ elements to iron ([$\alpha$/Fe]) and find that the CGM gas in the most overdense region exhibits a lower [$\alpha$/Fe] ratio. Our modeling of the galaxy's chemical abundance favors a top-heavy stellar initial mass function, and hints that we may be witnessing the contribution of the first generation Population III stars to the CGM at the end of reionization epoch.

M dwarf stars comprise 70-80% of the galaxy's stars and host most of its rocky planets. They also importantly differ from Sunlike stars in that they are "active" for billions of years or more: rotating quickly, flaring often, and emitting large amounts of UV and X-ray light. The effects of stellar activity upon both photometry and spectroscopy make their exoplanets more difficult to detect, and M dwarfs exhibit this behavior for thousands of times longer than a typical Sunlike star. While activity signals such as flaring and stellar rotation can be more readily modeled or removed from photometry, the contribution of unresolved stellar activity to transit sensitivity is harder to quantify. In this paper, we investigate the difference in the detectability of planetary transits around a sample of M dwarfs observed by NASA's TESS Mission, characterized by a common stellar radius, effective temperature, and TESS magnitude. Our sample is classified as either "active" or "inactive" based upon the presence of H$\alpha$ in emission. After removing the more readily identifiable signatures of activity: stellar rotation and large flares, we perform an injection-and-recovery analysis of transits for each star. We extract detection sensitivity as a function of planetary radius and orbital period for each star in the sample. Then, we produce averaged sensitivity maps for the "active" stars and the "inactive" stars, for the sake of comparison. We quantify the extent to which signal-to-noise is degraded for transit detection, when comparing an active star to an inactive star of the same temperature and apparent brightness. We aim for these sensitivity maps to be useful to the exoplanet community in future M dwarf occurrence rate studies.

The large distances travelled by neutrinos emitted from the Sun and core-collapse supernovae together with the characteristic energy of such neutrinos provide ideal conditions to probe their lifetime, when the decay products evade detection. We investigate the prospects of probing invisible neutrino decay capitalising on the detection of solar and supernova neutrinos as well as the diffuse supernova neutrino background (DSNB) in the next-generation neutrino observatories Hyper-Kamiokande, DUNE, JUNO, DARWIN, and RES-NOVA. We find that future solar neutrino data will be sensitive to values of the lifetime-to-mass ratio $\tau_1/m_1$ and $\tau_2/m_2$ of $\mathcal{O}(10^{-1} - 10^{-2})$ s/eV. From a core-collapse supernova explosion at $10$ kpc, lifetime-to-mass ratios of the three mass eigenstates of $\mathcal{O}(10^5)$ s/eV could be tested. After $20$ years of data taking, the DSNB would extend the sensitivity reach of $\tau_1/m_1$ to $10^{8}$ s/eV. These results promise an improvement of about $6 -15$ orders of magnitude on the values of the decay parameters with respect to existing limits.

In this paper, we use photometric data from the S-PLUS DR4 survey to identify isolated galaxy pairs and analyse their characteristics and properties. Our results align with previous spectroscopic studies, particularly in luminosity function parameters, suggesting a consistent trait among galaxy systems. Our findings reveal a high fraction of red galaxies across all samples, irrespective of projected distance, velocity difference, or luminosity ratio. We found that the proximity of a neighbour to its central galaxy influences its colour due to environmental effects. We also found that central and neighbour have different behaviours: central galaxies maintain a stable red colour regardless of luminosity, while neighbour colours vary based on luminosity ratios. When the central is significantly brighter, the neighbour tends to be less red. According to our division in red, blue and mixed pairs, we found evidence of galactic conformity. Red pair fractions increase in closer pairs and in pairs of similar luminosity, indicating shared environments promoting red galaxy formation. Analysing local density, the expected colour-density relation is of course recovered, but it is strongly determined by the stellar mass of the pair. In denser environments, the red pair fractions increase, blue pairs decrease and for mixed pairs it depends on their stellar mass: more massive mixed pairs decrease their fraction whereas the lower massive ones increase it. These results shed light on the intricate relationship between galaxy pairs, their characteristics, and environmental influences on colour, providing insights into their evolutionary histories.

Low-mass planets migrate in the type-I regime. In the inviscid limit, the contrast between the vortensity trapped inside the planet's corotating region and the background disk vortensity leads to a dynamical corotation torque, which is thought to slow down inward migration. We investigate the effect of radiative cooling on low-mass planet migration using inviscid 2D hydrodynamical simulations. We find that cooling induces a baroclinic forcing on material U-turning near the planet, resulting in vortensity growth in the corotating region, which in turn weakens the dynamical corotation torque and leads to 2-3x faster inward migration. This mechanism is most efficient when cooling acts on a timescale similar to the U-turn time of material inside the corotating region, but is nonetheless relevant for a substantial radial range in a typical disk (5-50 au). As the planet migrates inwards, the contrast between the vortensity inside and outside the corotating region increases and partially regulates the effect of baroclinic forcing. As a secondary effect, we show that radiative damping can further weaken the vortensity barrier created by the planet's spiral shocks, supporting inward migration. Finally, we highlight that a self-consistent treatment of radiative diffusion as opposed to local cooling is critical in order to avoid overestimating the vortensity growth and the resulting migration rate.

We use 3-D K Means clustering to characterize galaxy substructure in the Abell 2146 cluster of galaxies (z = 0.2343). This method objectively characterizes the cluster's substructure using projected position and velocity data for 67 galaxies within a 2.305 Mpc circular region centered on the clusters optical center. The optimal number of substructures is found to be 4. Four distinct substructures with RMS velocity typical of galaxy groups or low mass subclusters, when compared to cosmological simulations of galaxy cluster formation, suggests that Abell 2146 is in the early stages of formation. We utilize this disequilibrium, that is so prevalent in galaxy clusters at all redshifts, to construct a radial mass distribution. Substructures are bound but not virialized. This method is in contrast to previous kinematical analyses, which have assumed virialization, and ignored the ubiquitous clumping of galaxies. The best fitting radial mass profile is much less centrally concentrated than the well known NFW profile, indicating that the dark matter dominated mass distribution is flatter pre-equilibrium, becoming more centrally peaked in equilibrium through merging of substructure.

The observed Tully-Fisher and Faber-Jackson laws between the baryonic mass of galaxies and the velocity of motion of stars at the edge of galaxies are explained within the framework of the model of accretion of galaxies around supermassive black holes (SMBH). The accretion model can also explain the M-sigma relation between the mass of a supermassive black hole and the velocity of stars in the bulge. The difference in the mechanisms of origin of elliptical galaxies with low angular momentum and disk galaxies with high angular momentum can be associated with 3D and 2D accretion.

All-sky maps of the thermal Sunyaev-Zel'dovich effect (SZ) tend to suffer from systematic features arising from the component separation techniques used to extract the signal. In this work, we investigate one of these methods known as needlet internal linear combination (NILC) and test its performance on simulated data. We show that NILC estimates are strongly affected by the choice of the spatial localization parameter ($\Gamma$), which controls a bias-variance trade-off. Typically, NILC extractions assume a fixed value of $\Gamma$ over the entire sky, but we show there exists an optimal $\Gamma$ that depends on the SZ signal strength and local contamination properties. Then we calculate the NILC solutions for multiple values of $\Gamma$ and feed the results into a neural network to predict the SZ signal. This extraction method, which we call Deep-NILC, is tested against a set of validation data, including recovered radial profiles of resolved systems. Our main result is that Deep-NILC offers significant improvements over choosing fixed values of $\Gamma$.

AD Leo is a young and active M dwarf with high flaring rates across the X-ray to radio bands. Flares accelerate particles in the outer coronal layers and often impact exospace weather. Wide-band radio dynamic spectra let us explore the evolution of particle acceleration activity across the corona. Identifying the emission features and modelling the mechanisms can provide insights into the possible physical scenarios driving the particle acceleration processes. We performed an 8 h monitoring of AD Leo across the 550 - 850 MHz band using upgraded-Giant Metrewave Radio Telescope (uGMRT). A python routine, named VISAD, was built to obtain the visibility averaged wide-band dynamic spectra. Direct imaging was also performed. Based on existing observational results on AD Leo and on solar active region models, radial profiles of electron density and magnetic fields were derived. Applying these models, we explore the possible emission mechanisms and magnetic field structure of the active region. The star displayed high brightness temperature ($\approx 10^{10} - 10^{11}$ K) throughout the observation with nearly 100% left circularly polarised bursts. Post flare phase is characterised by a highly polarised (60 - 80%) solar-like type IV burst confined above 700 MHz.The flare emission favors a Z-mode or a higher harmonic X-mode electron cyclotron maser emission mechanism. The post-flare activity above 700 MHz is consistent with a type-IV radio burst from flare-accelerated particles trapped in magnetic loops, which could be a coronal mass ejection (CME) signature. This is the first solar-like type-IV burst reported on a young active M dwarf belonging to a different age - related activity compared to the Sun. We also find that, a multipole expansion model of the active region magnetic field better accounts for the observed radio emission than a solar-like active region profile.

Evolved cool stars of various masses are major cosmic engines, delivering substantial mechanical and radiative feedback to the interstellar medium through strong stellar winds and supernova ejecta. These stars play a pivotal role in enriching the interstellar medium with vital chemical elements that constitute the essential building blocks for forming subsequent generations of stars, planets, and potentially even life. Within the complex tapestry of processes occurring in the atmospheres of these cool and luminous stars, convection takes center stage. Convection is a non-local, complex phenomenon marked by non-linear interactions across diverse length scales within a multi-dimensional framework. For these particular stars, characterized by their considerable luminosities and extensive scale heights, convection transitions to a global scale. This transition is facilitated by transmitting radiative energy through the non-uniform outer layers of their atmospheres. To fully understand this phenomenon, the application of global comprehensive 3D radiation-hydrodynamics simulations of stellar convection is of paramount importance. We present two state-of-the-art numerical codes: CO5BOLD and Athena++. Furthermore, we provide a view on their applications as: pivotal roles in enabling a comprehensive investigation into the dynamic processes linked to convection; and critical tools for accurately modeling the emissions produced during shock breakouts in Type II-P Supernovae.

A joint campaign of several space-borne and ground-based observatories, such as the GREGOR solar telescope, the Extreme-ultraviolet Imaging Spectrometer (EIS), and the Interface Region Imaging Spectrograph (Hinode Observing Plan 381, 11-22 October 2019) was conducted to investigate the plasma $\beta$ in quiet sun regions. In this work, we focus on October 13, 17, and 19, 2019, to obtain the plasma $\beta$ at different heights through the solar atmosphere based on multi-height observational data. We obtained temperature, density and magnetic field estimates from the GREGOR High-resolution Fast Imager (HiFI), and Infrared Spectrograph (GRIS), IRIS, EIS and complementary data from SDO/AIA. Using observational data and models (e.g., FALC and PFSS), we determined the plasma $\beta$ in the photosphere, chromosphere, transition region and corona. The obtained plasma $\beta$ values lie inside the expected ranges through the solar atmosphere. However, at EIS and AIA coronal heights (from $1.03\ R_{\odot}$ to $1.20\ R_{\odot}$) plasma $\beta$ values appear in the limit defined by Gary (2001); such behavior was previously reported by Rodr\'iguez G\'omez et al. (2019). Additionally, we obtained the plasma $\beta$ in the solar photosphere at different optical depths from $\log\ \tau=-1.0$ to $\log\ \tau=-2.0$. These values decrease with optical depth. This work provides a complete picture of plasma $\beta$ in quiet sun regions through the solar atmosphere, which is a pre-requisite of a better understanding of the plasma dynamics at the base of the solar corona.

The recent astrometric data of hundreds of millions of stars from Gaia DR3 has allowed a precise determination of the Milky Way rotation curve up to $28$ kpc. The data suggests a rapid decline in the density of dark matter beyond $19$ kpc. We fit the whole rotation curve with four components (gas, disk, bulge and halo) and compute the microlensing optical depth to the Large Magellanic Cloud (LMC). With this model of the galaxy we reanalize the microlensing events of the MACHO and EROS-2 Collaborations. Using their published efficiency function for the duration of their surveys, together with the rate of expected events according to the new density profile, we find that the Dark Matter halo could be composed up to 100\% of massive compact halo objects (MACHOs) for any mass between $0.001$ to $100~M_\odot$, except a narrow range around $0.3~M_\odot$, where it cannot be larger than $\sim30\%$. This result assumes that MACHOs have all the same mass. If these were distributed in an extended mass function like that of the Thermal History Model, the constraints are weakened, allowing 100\% of all DM in the form of Primordial Black Holes.

Spatially-resolved images of debris disks are necessary to determine disk morphological properties and the scattering phase function (SPF) which quantifies the brightness of scattered light as a function of phase angle. Current high-contrast imaging instruments have successfully resolved several dozens of debris disks around other stars, but few studies have investigated trends in the scattered-light, resolved population of debris disks in a uniform and consistent manner. We have combined Karhunen-Loeve Image Projection (KLIP) with radiative-transfer disk forward modeling in order to obtain the highest quality image reductions and constrain disk morphological properties of eight debris disks imaged by the Gemini Planet Imager at H-band with a consistent and uniformly-applied approach. In describing the scattering properties of our models, we assume a common SPF informed from solar system dust scattering measurements and apply it to all systems. We identify a diverse range of dust density properties among the sample, including critical radius, radial width, and vertical width. We also identify radially narrow and vertically extended disks that may have resulted from substellar companion perturbations, along with a tentative positive trend in disk eccentricity with relative disk width. We also find that using a common SPF can achieve reasonable model fits for disks that are axisymmetric and asymmetric when fitting models to each side of the disk independently, suggesting that scattering behavior from debris disks may be similar to Solar System dust.

The physical diagnosis of the solar atmosphere is achieved by solving the polarized radiative transfer problem for plasmas in Non-Local Thermodynamical Equilibrium (NLTE). This scenario poses theoretical challenges for integrating the radiative transfer equation (RTE) efficiently. Namely, current methods are limited to constant propagation matrices, thus imposing local solutions. To spark significant advances, this paper lays the foundations of a formalism that achieves an efficient non-local integration of the RTE based on the Magnus expansion. First, we revisit the problem and its solutions in Jones and Stokes formalisms. Looking at them as equivalent representations of the Lorentz/Poincar\'e group of rotations, we interpret the RTE in terms of Lie group theory to show the suitability of the Magnus expansion for obtaining non-local solutions. We then present a detailed algebraic characterization of the propagation matrix and combine it with the Magnus expansion to reformulate the homogenous solution to the RTE in Stokes formalism. Thus, we obtain a compact evolution operator supporting arbitrary variations of the propagation matrix to first order in the Magnus expansion. Finally, we reformulate the corresponding inhomogeneous solution as an equivalent homogeneous system, which is then solved with the Magnus expansion again. This gives the first efficient and consistent formal solution of the RTE that furthermore is non-local, natively accurate, and that separates the integration from the formal solution. Such disruptive formulation leads to a new whole family of numerical radiative transfer methods and suggests accelerating NLTE syntheses and inversions with non-local radiative transfer. With minor cosmetic changes, our results are valid for other universal physical problems sharing the Lorentz/Poincar\'e algebra of the RTE and special relativity

Recent observational surveys of the outer Solar System provide evidence that Neptune's distant $n$:1 mean-motion resonances may harbor relatively large reservoirs of trans-Neptunian objects (TNOs). In particular, the discovery of two securely classified 9:1 resonators, 2015 KE$_{172}$ and 2007 TC$_{434}$, by the Outer Solar System Origins Survey is consistent with a population of order $10^4$ such objects in the 9:1 resonance with absolute magnitude $H_r < 8.66$. This work investigates whether the long-term stability of such populations in Neptune's $n$:1 resonances can be used to constrain the existence of distant $5-10M_{\oplus}$ planets orbiting at hundreds of AU. The existence of such a planet has been proposed to explain a reported clustering in the orbits of highly eccentric "extreme" trans-Neptunian objects (eTNOs), although this hypothesis remains controversial. We engage in a focused computational case-study of the 9:1 resonance, generating synthetic populations and integrating them for 1 Gyr in the presence of 81 different test planets with various masses, perihelion distances, eccentricities, and inclinations. While none of the tested planets are incompatible with the existence of 9:1 resonators, our integrations shed light on the character of the interaction between such planets and nearby $n$:1 resonances, and we use this knowledge to construct a simple, heuristic method for determining whether or not a given planet could destabilize a given resonant population. We apply this method to the currently estimated properties of Planet 9, and find that a large primordial population in the 15:1 resonance (or beyond), if discovered in the future, could potentially constrain the existence of this planet.

If a galactic supernova explosion occurs in the future, it will be critical to rapidly alert the community to the direction of the supernova by utilizing neutrino signals in order to enable the initiation of follow-up optical observations. In addition, there is anticipation that observation of the diffuse supernova neutrino background will yield discoveries in the near future, given that experimental upper limits are approaching theoretical predictions. We have developed a new supernova event simulator for water Cherenkov neutrino detectors, such as the highly sensitive Super-Kamiokande. This simulator calculates the neutrino interaction in water for the two types of supernova neutrinos described above. Its purpose is to evaluate the precision in determining the location of supernovae and to estimate the expected number of events related to the diffuse supernova neutrino background in Super-Kamiokande. In this paper, we describe the basic structure of the simulator and its demonstration.

Machine learning photo-z methods, trained directly on spectroscopic redshifts, provide a viable alternative to traditional template fitting methods but may not generalise well on new data that deviates from that in the training set. In this work, we present a Hybrid Algorithm for WI(Y)de-range photo-z estimation with Artificial neural networks and TEmplate fitting (HAYATE), a novel photo-z method that combines template fitting and data-driven approaches and whose training loss is optimised in terms of both redshift point estimates and probability distributions. We produce artificial training data from low-redshift galaxy SEDs at z<1.3, artificially redshifted up to z=5. We test the model on data from the ZFOURGE surveys, demonstrating that HAYATE can function as a reliable emulator of EAZY for the broad redshift range beyond the region of sufficient spectroscopic completeness. The network achieves precise photo-z estimations with smaller errors ($\sigma_{NMAD}$) than EAZY in the initial low-z region (z<1.3), while being comparable even in the high-z extrapolated regime (1.3<z<5). Meanwhile, it provides more robust photo-z estimations than EAZY with the lower outlier rate ($\eta_{0.2}\lesssim 1\%$) but runs $\sim100$ times faster than the original template fitting method. We also demonstrate HAYATE offers more reliable redshift PDFs, showing a flatter distribution of Probability Integral Transform scores than EAZY. The performance is further improved using transfer learning with spec-z samples. We expect that future large surveys will benefit from our novel methodology applicable to observations over a wide redshift range.

By performing three-dimensional radiation hydrodynamics simulations, we study Bondi-Hoyle-Lyttleton accretion onto intermediate-mass black holes (BHs) wandering in the dusty gas. Here, we take into account the anisotropic radiation feedback and the sublimation of dust grains. Our simulations show that when the relative velocity between the BH and the gas is small (~20 km/s) and gas density is ~10^4/cm^3, the gas mainly accretes from near the equatorial plane of the accretion disk at a time-averaged rate of 0.6% of the Bondi-Hoyle-Lyttleton rate. An ionized region like two spheres glued together at the equatorial plane is formed, and the dense shock shell appears near the ionization front. The BH is accelerated at ~10^-8cm/s^2 due to the gravity of the shell. For denser gas (~10^6/cm^3), the time-averaged accretion rate is also 0.6% of the Bondi-Hoyle-Lyttleton rate.However, the BH is decelerated at ~10^-7cm/s^2 due to gravity of the dense downstream gas although the dense shock shell appears upstream. Our simulations imply that intermediate-mass BHs in the early universe keep floating at > several 10km/s without increasing mass in interstellar gas with density of ~10^4/cm^3, and slow down and grow into supermassive BHs in galaxies with the density of ~10^6/cm^3.

Rigorous implementation of the effects of collisions in modeling the formation of the polarized solar lines is of utmost importance in order to realistically analyze the available, highly sensitive solar spectropolarimetric observations. Indeed, even when an observation seems to fit well with theory, one can misinterpret results if important effects due to collisions are not correctly implemented in the modeling process. We point out inconsistencies in the models adopted to implement the Paschen Back effect together with collisional effects on the solar linear polarization formed by scattering of anisotropic radiation. Because the significance of these inconsistencies increases as polarization becomes increasingly responsive to collisions, we investigate the range of hydrogen densities $n_\text{H}$ to which the polarization is sensitive. We used the density matrix formalism in the tensorial irreducible basis, which was developed within the theory of atom-radiation interaction and of atomic collisions. We solved the statistical equilibrium equations for multi-level atoms with hyperfine structure (HFS) in order to evaluate the collisional depolarization of levels of the D1-D2 lines of the K I atom. We find that collisions play a prominent role, particularly at hydrogen densities of between 10$^{13}$ and 10$^{16}$ cm$^{-3}$. So far, analyses of polarized lines formed in the presence of solar magnetic field have incorporated, if at all, collisional rates calculated assuming zero magnetic field. This could be a good approximation in the Hanle regime but not in the Paschen Back regime. For typical quiet Sun magnetic fields, the latter regime could be reached, and level-crossing takes place in several atomic systems. Therefore, one must be careful when using collisional rates calculated in the zero-field case to interpret linear polarization formed in magnetized media.

Axions or axion-like particles (ALPs) are one of the most promising candidates of dark matter (DM). A prevalent method to detect axion-like DM is to seek the periodic oscillation feature in the polarization angles of linearly polarized light emitted from astrophysical sources. In this work, we use the time-resolved polarization measurements of the hyperactive repeating fast radio burst, FRB 20220912A, detected by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to search for extragalactic axion-like DM for the first time. Given a DM density profile of FRB 20220912A's host, we obtain upper limits on the ALP-photon coupling constant of $g_{a \gamma}<(2.9 \times 10^{-11}-1.1\times 10^{-9})\,\mathrm{GeV}^{-1}$ for the ALP masses $m_a \sim (1.4\times10^{-21}-5.2\times10^{-20})$ eV. Persistent polarimetric observations with FAST would further improve the constraints. We prove that FRBs offer an alternative way to detect axion-like DM on extragalactic distance scales, complementary to other galactic DM probes.

We examine critically recent claims for the presence of above-atmosphere optical transients in publicly-available digitised scans of Schmidt telescope photographic plate material derived from the National Geographic Society-Palomar Observatory Sky Survey. We employ the publicly available SuperCOSMOS Sky Survey catalogues to examine statistically the morphology of the sources. We develop a simple, objective and automated image classification scheme based on a random forest decision tree classifier. We find that the putative transients are likely to be spurious artefacts of the photographic emulsion. We suggest a possible cause of the appearance of these images as resulting from the copying procedure employed to disseminate glass copy survey atlas sets in the era before large-scale digitisation programmes.

Combining findings from New Horizons' suite of instruments reveals a bimodal haze particle distribution within Pluto's atmosphere, which haze models have not been able to reproduce. We employ the photochemical and microphysics KINAERO model to simulate seasonal cycles and their impact on the haze distribution. We find that the smaller spherical particle mode can be generated through photochemistry and coagulation, while the larger aggregate mode are formed by surface volatile deposits sublimating and subsequently lofting such particles upwards.

There are several new projects to survey the sky with millimetre eyes, the biggest being Simons Observatory and CMB-S4, in the Southern Hemisphere. The NIKA2 collaboration has acquired sufficient knowledge to build a large focal plane KID camera for a 15~m antenna. This would allow covering the whole Northern Hemisphere in five years at subarcminute resolution and with milliJansky point-source sensitivity. We describe the main scientific drivers for such a project: the SZ sky, the high-redshift millimetre Universe and the interstellar medium in our Galaxy and the nearby galaxies. We also show briefly the main difficulties (scientific, organisational, technical and financial).

Detailed modelling of the spectro-spatial distributions of energetic electrons and protons in galactic discs and haloes of starburst galaxies (SBGs) is needed in order to follow their interactions with the magnetized interstellar medium and radiation fields, determine their radiative yields, and for estimating their residual spectral densities in intergalactic environments. We have developed a semi-analytical approach for calculating the particle spectro-spatial distributions in the disc and halo based on a diffusion model for particle propagation from acceleration sites in the central SB and disc regions, including all their relevant interaction modes. Important overall normalization of our models is based on previous modelling of the Galactic disc (with the GALPROP code), scaled to the higher star-formations rate in NGC253, and on spatially resolved radio measurements of the central SB and disc. These provide the essential input for determining the particle distributions and their predicted radiative yields in the outer disc and inner halo for a range of values of the key parameters that affect diffusion rate and energy losses. Results of our work clearly indicate that quantitative description of non-thermal emission in SBGs has to be based on modelling of the particle distributions in the entire disc, not just the central SB region.

Cataclysmic variables can experience short optical brightenings, which are commonly attributed to phenomena such as dwarf novae outbursts, micronovae, donor flares or magnetic gating bursts. Since these events exhibit similar observational characteristics, their identification has often been ambiguous. In particular, magnetic gating bursts and micronovae have been suggested as alternative interpretations of the same phenomena. Here we show that the timescales and energies separate the optical brightenings into separate clusters consistent with their different classifications. This suggest that micronovae and magnetic gating bursts are in fact separate phenomena. Based on our finding we develop diagnostic diagrams that can distinguish between these bursts/flares based on their properties. We demonstrate the effectiveness of this approach on observations of a newly identified intermediate polar, CTCV J0333-4451, which we classify as a magnetic gating system. CTCV J0333-4451 is the third high spin-to-orbital period ratio intermediate polar with magnetic gating, suggesting that these bursts are common among these rare systems.

JWST has recently detected numerous disc galaxies at high-redshifts and there have been observations of cold disc galaxies at z > 4 with ALMA. In the Milky Way, recent studies find metal-poor stars in cold disc orbits, suggesting an ancient disc. We investigated a sample of 565,606 stars from the hybrid-CNN analysis of the Gaia-DR3 RVS stars. The sample contains 8,500 stars with [Fe/H]<-1. For a subset of ~200,000 main sequence turnoff and subgiant stars we computed distances and ages using the StarHorse code with a mean precision of 1% and 12%, respectively. First, we confirm the existence of metal-poor stars in thin disc orbits - over 50% are older than 13 Gyr. Second, we report the discovery of the oldest thin disc of the Milky Way extending across a wide range of metallicities from metal-poor to super-solar. The metal-poor stars in disc orbits manifest as a readily visible tail of the metallicity distribution. The high-[{\alpha}/Fe] thick disc exhibits a vertical velocity dispersion of 35 km/s, while the thin disc shows 10 to 15 km/s lower at similar ages. Our old thin disc $\sigma_{V_z}$ appears similar to those estimated for the high-z disc galaxies. Third, we extend the [Y/Mg] chemical clock to the oldest ages and estimate a slope of -0.038 dex/Gyr. Finally, we show that the Splash includes both old (> 9 Gyr) high- and low-[{\alpha}/Fe] populations and extends to super-solar [Fe/H]. We find about 6 to 10% of the old thin disc was heated to thick disc orbits with the youngest splashed stars being 9 to 10 Gyrs. We conclude the Milky Way thin disc forms <1 billion years from Big Bang, building up inside-out, preceding earlier estimates by about 4-5 billion years. Considering a massive merger event such as the GSE, a Splash is expected - we find a portion of the old thin disc is heated to thick disc velocities and the Splash extends to super-solar [Fe/H] regimes.

Context: Cosmic ray acceleration in galaxy clusters is still an ongoing puzzle, with relativistic electrons forming radio relics at merger shocks and emitting synchrotron radiation. In the present work we perform hybrid-kinetic simulations in a range of various quasi-perpendicular foreshock conditions, including plasma beta, magnetic obliquity, and the shock Mach number. Aims: We study the ion kinetic physics, responsible for the shock structure and wave turbulence, that in turn affects the particle acceleration processes. Methods: We apply a recently developed generalized fluid-particle hybrid numerical code that can combine fluid modeling for both kinetic ions and fluid electrons. The model utilizes the exact form of the generalized Ohm's law, allowing for arbitrary choice of mass and energy densities, as well as the charge-to-mass ratio of the kinetic species. Results: We show that the properties of ion-driven multi-scale magnetic turbulence in merger shocks are in agreement with the ion structures observed in PIC simulations. In typical shocks with the sonic Mach number $M_s=3$, the magnetic structures and shock front density ripples grow and saturate at wavelengths reaching approximately four ion Larmor radii. Finally, we note that the steady-state structure of $M_s=3$ shocks in high-beta plasmas shows evidence that there is little difference between 2D and 3D simulations. The turbulence near the shock front seems to be a 2D-like structure in 3D simulations.

This paper presents a multiwavelength Sun-as-a-star analysis of the M8.7 flare on 2022 October 2, which were associated with a filament eruption and the following coronal mass ejection. The Sun-as-a-star analysis was performed using H$\alpha$ data taken by Solar Dynamics Doppler Imager on board the Solar Magnetic Activity Research Telescope at Hida Observatory, Kyoto University and full-disk integrated extreme ultraviolet (EUV) spectra taken by the Extreme ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory. The Sun-as-a-star H$\alpha$ spectra showed blueshifted absorption corresponding to the filament eruption. Furthermore, the EVE O {\sc v} 629.7 {\AA} spectra showed blueshifted brightening, which can also be attributed to the filament eruption. Even when the blueshifted absorption became almost invisible in the Sun-as-a-star H$\alpha$ spectra, the O {\sc v} blueshifted brightening up to $-400$ km s$^{-1}$ was still clearly visible. This result indicates that even when the shifted components--which are expected to originate from stellar eruptions--become almost invisible in the spatially integrated stellar H$\alpha$ spectra, the erupting materials may still be present and observable in EUV spectra. Additionally, the Sun-as-a-star H$\alpha$ and O {\sc v} spectra exhibited redshifted absorption and brightening, respectively, during the decay phase of the flare. These components probably originate from the post-flare loops, providing clues for the multi-temperature nature of the post-flare loops in the spatially integrated observation. Our Sun-as-a-star results suggest that the combination of H$\alpha$ and EUV lines allows the investigation of the multi-temperature structure and temporal development of stellar active phenomena even in spatially integrated spectra.

Using an excursion-set approach, we revisit the initial spatial clustering of Primordial Black Holes (PBHs) originating from the Hubble re-entry of large Gaussian density fluctuations in the early universe. We derive the two-point correlation functions of PBHs, properly accounting for the "cloud-in-cloud" mechanism. Our expressions naturally and intrinsically correlate the formation of pairs of PBHs, which is a key difference with the Poisson model of clustering. Our approach effectively includes short-range exclusion effects and clarifies the clustering behaviors at small scale: PBHs are anti-correlated at short distances. Using a scale-independent collapse threshold, we derive explicit expressions for the excess probability to find pairs of PBHs separated by a distance $r$, as well as the excess probability to find pairs with asymmetric mass ratio. Our framework is model-independent by construction and we discuss possible other applications.

This document attempts to summarize the Gamma ray section of the 38th International Cosmic Ray Conference held in Nagoya. There were 387 contributions submitted to this section distributed in 22 parallel oral and three poster sessions, plus four related highlight or review talks. The information included in this contribution is a description of what was reported at the conference, that represent the state of the art of the field.

Most tools for astrophysical research was centered on visual display. Even after some studies shows that the use of sound could help the data analysis, and on the other hand generate more accessibility. This fact motivates the creation of a tool centered on the researcher with and without visual impairments. To carry out this challenge, on this contribution, a theoretical framework based on visual impaired people was created and included on the sonoUno software. After that, the accessibility of the tool was analysed with the ISO standard 9241-171:2008.

General circulation models (GCMs) are valuable instruments to understand the most peculiar features in the atmospheres of planets and the mechanisms behind their dynamics. Venus makes no exception and it has been extensively studied thanks to GCMs. Here we validate the current version of the Institut Pierre Simon Laplace (IPSL) Venus GCM, by means of a comparison between the modelled temperature field and that obtained from data by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) and the Venus Express Radio Science Experiment (VeRa) onboard Venus Express. The modelled thermal structure displays an overall good agreement with data, and the cold collar is successfully reproduced at latitudes higher than +/-55\deg, with an extent and a behavior close to the observed ones. Thermal tides developing in the model appear to be consistent in phase and amplitude with data: diurnal tide dominates at altitudes above 10^2 Pa pressure level and at high-latitudes, while semidiurnal tide dominates between 10^2 and 10^4 Pa, from low to mid-latitudes. The main difference revealed by our analysis is located poleward of 50\deg, where the model is affected by a second temperature inversion arising at 10^3 Pa. This second inversion, possibly related to the adopted aerosols distribution, is not observed in data.

Blazars are a highly variable subclass of active galactic nuclei that have been observed to vary significantly during a single night. This intranight variability remains a debated phenomenon, with various mechanisms proposed to explain the behaviour including jet energy density evolution or system geometric changes. We present the results of an intranight optical monitoring campaign of four blazars: TXS 0506+056, OJ287, PKS 0735+178, and OJ248 using the Carlos S\'anchez Telescope. We detect significant but colourless behaviour in OJ287 and both bluer- and redder-when-brighter colour trends in PKS 0735+178. Additionally, the g band shows a lag of ~10 min with respect to the r,i,z_s bands for PKS 0735+178 on 2023 January 17. This unexpected hard-lag in PKS 0735+178 is not in accordance with the standard synchrotron shock cooling model (which would predict a soft lag) and instead suggests the variability may be a result of changes in the jet's electron energy density distribution, with energy injection from Fermi acceleration processes into a post-shocked medium.

X-ray emission is an important tracer of stellar magnetic activity. We carried out a systematic correlation analysis for the X-ray luminosity $\log L_{\rm X}$, bolometric luminosity $\log L_{\rm bol}$, and X-ray activity level $\log(L_{\textrm{X}}$/$L_{\textrm{bol}})$ versus the binary parameters including orbital period $P$, Rossby number $R_{\rm O}$, effective temperature $T_{\rm eff}$, metallicity [Fe/H] and the surface gravity $\log g$, and the stellar mass $M$ \& radius $R$, by assembling a large sample of semi-detached (EB-type) binaries with X-ray emission (EBXs). The fact that both $\log L_{\rm X}$ and $\log L_{\rm bol}$ change in accordance with $\log P$ indicates that X-ray emission originates from the convection zone, while $\log L_{\rm X}$ is proportional to the convection zone area. We found that EBXs with main-sequence components exhibit an upward and then a downward trend in both the $\log T_{\rm eff}$-$\log L_{\textrm{X}}$ and $M$-$\log L_{\textrm{X}}$ relations, which is different from the monotonically decreasing trend shown by EBXs containing sub-giant and giant components. The magnetic activity level is negatively correlated with $\log T_{\rm eff}$ and stellar mass. Based on the magnetic dynamo model, the variations in the size and thickness of the surface convection zones can explain the observed relations. EBXs with main-sequence components have similar $R_{\rm O}$-$\log(L_{\textrm{X}}/L_{\textrm{bol}})$ relationship to that of the binaries in the clusters as Praesepe and Hyade. We compared the X-ray radiation properties of EBXs with those of the X-ray-emitting contact binaries and found that EBXs have broader value ranges for $\log L_{\rm X}$ and $\log(L_{\textrm{X}}$/$L_{\textrm{bol}})$.

We consider an intermediate Dirac-Born-Infeld (DBI) inflationary model in the presence of a minimal measurable length in the theory. We show that, the presence of a minimal measurable length modifies the definitions of the scalar and tensor spectral indices and also other inflation observables. This is due to modification of the momentum and corresponding wave number of the perturbations in the presence of a minimal length. By using the deformed definition of the scalar and tensor spectral indices, we perform numerical analysis on the intermediate DBI inflation model to find some constraints on the deformation parameter. In this regard, we compare our numerical results with both Planck2018 TT, TE, EE +lowE +lensing +BAO+ BK14 and Planck2018 TT, TE,EE +lowE+lensing+BK14 +BAO+LIGO $\&$ Virgo2016 data at the $68\%$ CL and $95\%$ CL. Our numerical study shows that the intermediate DBI inflation model in the presence of a minimal measurable length is observationally viable if the upper bound on the deformation parameter to be considered of the order of $10^{48}$ at $68\%$ CL and $10^{49}$ at $95\%$ CL. This is consistent with the results of other approaches to constrain such a quantity.

1RXS J083842.1$-$282723 is a nearly synchronous magnetic cataclysmic variable with a simple X-ray light curve. While its orbital period was fairly well established at $P_{\rm orb}=98.4$ minutes from optical spectroscopy, indirect estimates of $P_{\rm spin}/P_{\rm orb}$ ranged from 0.90 to 0.96 because the short X-ray light curves could not determine the beat period to a factor of 2. We analyze a recent 50 day TESS observation, and ground-based optical time-series photometry spanning 9 years, that together measure precise beat, orbit, and spin periods and enable the X-ray and optical modulations to be phase aligned. Although the X-ray light curves do not distinguish between a beat period of 16.11 or 32.22 hours, all of the optical evidence favors the longer value, with complete pole switching of accretion every half beat cycle. This would require $P_{\rm spin}/P_{\rm orb}=0.952$. Long-term optical monitoring also shows a decline in accretion rate, and a change in the beat-folded light curve. It would be useful to obtain a new X-ray/optical observation of at least 32 hours duration to examine any associated change in accretion structure, and confirm the spin and beat periods.

Venus' atmosphere shows highly variable warm vortices over both of the planet's poles. The nature of the mechanism behind their formation and properties is still unknown. Potential vorticity is a conserved quantity when advective processes dominate over friction and diabatic heating, and is a quantity frequently used to model balanced flows. As a step toward understanding the vortices' dynamics, we present maps of Ertel's potential vorticity (EPV) at Venus' south polar region. We analyze three configurations of the South Polar Vortex at the upper cloud level ($P\sim 240 mbar$; $z\sim 58 km$), based on our previous analyses of cloud motions and thermal structure from data acquired by the VIRTIS instrument onboard Venus Express. Additionally, we tentatively estimate EPV at the lower cloud level ($P\sim 2200 mbar$; $z\sim 43 km$), based on our previous wind measurements and on static stability data from Pioneer Venus and the VIRA model. Values of EPV are on the order of $10^{-6}$ and $10^{-8} K m^2 kg^{-1} s^{-1}$ at the upper and lower cloud levels, respectively, being 3 times larger than the estimated errors. The morphology observed in EPV maps is mainly determined by the structures of the vertical component of the relative vorticity. This is in contrast to the vortex's morphology observed in 3.8 or 5 $\mu m$ images which are related to the thermal structure of the atmosphere at the cloud top. Some of the EPV maps point to a weak ringed structure in the upper cloud while a more homogenous EPV field is found in the lower cloud.

The expanding ejecta of supernova remnants (SNRs) are believed to form dust in dense clumps of gas. Before the dust can be expelled into the interstellar medium and contribute to the interstellar dust budget, it has to survive the reverse shock that is generated through the interaction of the preceding supernova blast wave with the surrounding medium. The conditions under which the reverse shock hits the clumps change with remnant age and define the dust survival rate. To study the dust destruction in the SNR Cassiopeia A, we conduct magnetohydrodynamical simulations of the evolution of a supernova blast wave and of the reverse shock. In a second step we use these evolving conditions to model clumps that are disrupted by the reverse shock at different remnant ages. Finally, we compute the amount of dust that is destroyed by the impact of the reverse shock. We find that most of the dust in the SNR is hit by the reverse shock within the first 350 yr after the SN explosion. While the dust destruction in the first 200 yr is almost complete, we expect greater dust survival rates at later times and almost total survival for clumps that are first impacted at ages beyond 1000 yr. Integrated over the entire evolution of the SNR, the dust mass shows the lowest survival fraction (17 per cent) for the smallest grains (1 nm) and the highest survival fraction (28 per cent) for the largest grains (1000 nm).

We present the study of CI/H$_2$ relative abundance in the diffuse cold neutral medium. Using the chemical and thermal balance model we calculated the dependence of CI/H$_2$ on the main parameters of the medium: hydrogen number density, metallicity, strength of the UV field, and cosmic ray ionization rate (CRIR). We show that observed relative CI and H$_2$ column densities in damped Lyman alpha systems (DLAs) at high redshifts can be reproduced within our model assuming the typically expected conditions in the diffuse cold neutral medium (CNM). Using the additional observed information the on metallicity, HI column density, and excitation of CI fine-structure levels, as well as temperature we estimated for a wide range metallicities in the CNM at high redshifts that CRIRs to be in the range from $\sim10^{-16}$ to $\rm few \times 10^{-15}\rm s^{-1}$, hydrogen number densities to be in range $\sim10 - 10^3$cm$^{-3}$, and UV field in range from $10^{-2}$ to $\rm few \times 10^2$ of Mathis field. We argue, that since the observed quantities used in this work are quite homogeneous and much less affected by the radiative transfer effects (in comparison with e.g. dissociation of HD and UV pumping of H$_2$ rotational levels) our estimates are quite robust against the assumption of the exact geometrical model of the cloud and local sources of the UV field.

We study the star-disc interaction in the presence of the strong magnetic field ($B_\star=6.2kG$) of a slowly rotating star. This situation describes a post-merger of the spectral type B and has not been previously investigated. We perform a set of resistive and viscosity $2.5D$-magnetohydrodynamical simulations using the PLUTO code. Based on our previous work, we consider the initial gas disc density $\rho_{d0}=10^{-13}\mathrm{gcm}^{-3}$ since it describes the conditions around IRAS 17449+2320 well. We find that the fall of gas towards the star occurs in the mid-plane, and remarkably, intermittent backflow takes place in the mid-plane in all of our models for $R\geq10R_\star$. However, we do not rule out that the funnel effect may occur and cause the accretion closer to the poles. Also, when larger values of viscosity ($\alpha_\nu=1$) and stellar rotation rate ($\delta_\star=0.2$) are considered, we find that the disc exhibits a thickening which is characteristic of FS~CMa-type stellar objects. Additionally, we find that the poloidal magnetic field lines twist over short periods of time, leading to magnetic reconnection causing coronal heating that could explain the presence of the Raman lines found observationally in several FS~CMa stars. Lastly, we find the formation of several knots in the magnetic field lines near and in the mid-plane of the disc which produce perturbations in the density and velocity components, as well as the formation of shallow gaps whose position depends on the inflation of the magnetic field lines.

We aim to characterise the magnetic field of the eclipsing binary CU Cnc. The determination of magnetic field parameters of this target enables comparisons with both observations of similar stars and theoretical predictions of the magnetic field strength for CU Cnc. The target is therefore providing an excellent opportunity to test our understanding of the generation of magnetic fields in low-mass stars and its impact on stellar structure. We use spectropolarimetric observations obtained with ESPaDOnS to investigate the magnetic properties of CU Cnc. We generate average line profiles with LSD, which are used to extract information about the radial velocities of the components, expanding the number of radial velocity measurements available and allowing for a determination of orbital parameters. Stokes V LSD profiles are used with ZDI to obtain large-scale magnetic field structures on both components. We also use polarised radiative transfer modelling to investigate the small-scale fields by utilising Zeeman splitting of magnetically sensitive Ti I lines in non-polarised spectra. The large-scale fields are dominantly poloidal and have an average strength of ~100 G on both components. This analysis of the large-scale fields likely suffers from some amount of hemisphere degeneracy due to the high inclination of the target. Both components also show unusual magnetic field configurations compared to stars with similar parameters, the primary is weakly axisymmetric (~10%) and the secondary has a strong torroidal contribution (~20%). The small-scale fields are significantly stronger, at 3.1 and 3.6 kG for the primary and secondary respectively. This measurement is in excellent agreement with surface field strength predictions for CU Cnc from magnetoconvective stellar evolution models. These results indicates that magnetic fields play a significant role in radius inflation of active stars.

According to the strange quark matter hypothesis, strange planets may exist, which are planetary mass objects composed of almost equal numbers of up, down and strange quarks. A strange planet can revolve around its host strange star in a very close-in orbit. When it finally merges with the host, strong gravitational wave emissions will be generated. Here the gravitational waveforms are derived for the merging process, taking into account the effects of the strange star's magnetic field on the dynamics. Effects of the inclination angle are also considered. Templates of the gravitational waveforms are derived. It is found that the magnetic interactions significantly speed up the merging process. Coalescence events of such strange planetary systems occurring in our Galaxy as well as in local galaxies can be effectively detected by current and future gravitational experiments, which may hopefully provide a new method to test the strange quark matter hypothesis and probe the magnetic field of compact stars.

Disequilibrium chemistry due to vertical mixing in the atmospheres of many brown dwarfs and giant exoplanets is well-established. Atmosphere models for these objects typically parameterize mixing with the highly uncertain $K_{\rm zz}$ diffusion parameter. The role of mixing in altering the abundances of C-N-O-bearing molecules has mostly been explored for solar composition atmospheres. However, atmospheric metallicity and the C/O ratio also impact atmospheric chemistry. Therefore, we present the \texttt{Sonora Elf Owl} grid of self-consistent cloud-free 1D radiative-convective equilibrium model atmospheres for JWST observations, which includes a variation of $K_{\rm zz}$ across several orders of magnitude and also encompasses sub-solar to super-solar metallicities and C/O ratios. We find that the impact of $K_{\rm zz}$ on the $T(P)$ profile and spectra is a strong function of both $T_{\rm eff}$ and metallicity. For metal-poor objects $K_{\rm zz}$ has large impacts on the atmosphere at significantly higher $T_{\rm eff}$ compared to metal-rich atmospheres where the impact of $K_{\rm zz}$ is seen to occur at lower $T_{\rm eff}$. We identify significant spectral degeneracies between varying $K_{\rm zz}$ and metallicity in multiple wavelength windows, in particular at 3-5 $\mu$m. We use the \texttt{Sonora Elf Owl} atmospheric grid to fit the observed spectra of a sample of 9 early to late T- type objects from $T_{\rm eff}=550-1150$ K. We find evidence for very inefficient vertical mixing in these objects with inferred $K_{\rm zz}$ values lying in the range between $\sim$ 10$^1$-10$^4$ cm$^2$s$^{-1}$. Using self-consistent models, we find that this slow vertical mixing is due to the observations probing mixing in the deep detached radiative zone in these atmospheres.

We present a new grid of cloudy atmosphere and evolution models for substellar objects. These models include the effect of refractory cloud species, including silicate clouds, on the spectra and evolution. We include effective temperatures from 900 to 2400 K and surface gravities from log g=3.5-5.5, appropriate for a broad range of objects with masses between 1 and 84 Jupiter masses. Model pressure-temperature structures are calculated assuming radiative-convective and chemical equilibrium. We consider the effect of both clouds and metallicity on the atmospheric structure, resulting spectra, and thermal evolution of substellar worlds. We parameterize clouds using the Ackerman & Marley (2001) cloud model, including cloud parameter fsed values from 1-8; we include three metallicities (-0.5, 0.0, and +0.5). Refractory clouds and metallicity both alter the evolution of substellar objects, changing the inferred temperature at a given age by up to 100-200 K. We compare to the observed photometry of brown dwarfs, finding broad agreement with the measured photometry. We publish the spectra, evolution, and other data products online with open access.

In this paper, two models of interest for Celestial Mechanics are presented and analysed, using both analytic and numerical techniques, from the point of view of the possible presence of regular and/or chaotic motion, as well as the stability of the considered orbits. The first model, presented in a Hamiltonian formalism, can be used to describe the motion of a satellite around the Earth, taking into account both the non-spherical shape of our planet and the third-body gravitational influence of Sun and Moon. Using semi-analytical techniques coming from Normal Form and Nekhoroshev theories it is possible to provide stability estimates for the orbital elements of its geocentric motion. The second dynamical system presented can be used as a simplified model to describe the motion of a particle in an elliptic galaxy having a central massive core, and is constructed as a refraction billiard where an inner dynamics, induced by a Keplerian potential, is coupled with an external one, where a harmonic oscillator-type potential is considered. The investigation of the dynamics is carried on by using tools of ODEs' theory and is focused on studying the trajectories' properties in terms of periodicity, stability and, possibly, chaoticity.

In this paper, we explore the significant, non-linear impact that stellar winds have on H ii regions. We perform a parameter study using three-dimensional radiative magnetohydrodynamic simulations of wind and ultraviolet radiation feedback from a 35 Msun star formed self-consistently in a turbulent, self-gravitating cloud, similar to the Orion Nebula (M42) and its main ionizing source Theta 1 Ori C. Stellar winds suppress early radiative feedback by trapping ionizing radiation in the shell around the wind bubble. Rapid breakouts of warm photoionized gas ('champagne flows') still occur if the star forms close to the edge of the cloud. The impact of wind bubbles can be enhanced if we detect and remove numerical overcooling caused by shocks crossing grid cells. However, the majority of the energy in the wind bubble is still lost to turbulent mixing between the wind bubble and the gas around it. These results begin to converge if the spatial resolution at the wind bubble interface is increased by refining the grid on pressure gradients. Wind bubbles form a thin chimney close to the star, which then expands outwards as an extended plume once the wind bubble breaks out of the dense core the star formed in, allowing them to expand faster than a spherical wind bubble. We also find wind bubbles mixing completely with the photoionized gas when the H ii region breaks out of the cloud as a champagne flow, a process we term 'hot champagne'.

The interaction between dark matter and dark energy can be incorporated into field theory models of dark energy that have proved successful in alleviating the coincidence problem. We review recent advances in this field, including new models and constraints from different astronomical data sets. We show that interactions are allowed by observations and can reduce the current tensions among different measurements of cosmological parameters. We extend our discussion to include constraints from non-linear effects and results from cosmological simulations. Finally, we discuss forthcoming multi-messenger data from current and future observational facilities that will help to improve our understanding of the interactions within the dark sector.

We present MIRI MRS observations of the large, multi-gapped protoplanetary disk around the T-Tauri star AS 209. The observations reveal hundreds of water vapor lines from 4.9 to 25.5 $\mu$m towards the inner $\sim1$ au in the disk, including the first detection of ro-vibrational water emission in this disk. The spectrum is dominated by hot ($\sim800$ K) water vapor and OH gas, with only marginal detections of CO$_2$, HCN, and a possible colder water vapor component. Using slab models with a detailed treatment of opacities and line overlap, we retrieve the column density, emitting area, and excitation temperature of water vapor and OH, and provide upper limits for the observable mass of other molecules. Compared to MIRI spectra of other T-Tauri disks, the inner disk of AS 209 does not appear to be atypically depleted in CO$_2$ nor HCN. Based on \textit{Spitzer IRS} observations, we further find evidence for molecular emission variability over a 10-year baseline. Water, OH, and CO$_2$ line luminosities have decreased by factors 2-4 in the new MIRI epoch, yet there are minimal continuum emission variations. The origin of this variability is yet to be understood.

It has been claimed in I. Arraut, 2023 EPL 144 29003 [arXiv:2311.05652] that General Relativity can generate effects equivalent to dark matter, based on a "new modified symmetry that emerges at galactic scale". We show that (i) the spacetime considered is unphysical, violating energy conditions everywhere; (ii) actually no new symmetry emerges, which results from incorrect definitions of angular momentum, velocity, and arclength in the proposed geometry; (iii) no Tully-Fisher law, or flat rotation curves are obtained either, they simply result from a series of errors in the equations.

Relativistic axions can be readily produced in a broad variety of transient sources, such as axion star bosenova explosions or supernovae. We develop a general framework describing the resulting persistent diffuse axion background (D$a$B) due to accumulated axions from historic transient events. We derive strong constraints on the D$a$B flux from light axions $m\lesssim 10^{-3}\,{\rm eV}$ emitted from sources with energies $\omega\gtrsim{\rm MeV}$ considering the non-observation of excess photons associated with axion-photon coupling from experiments, including COMPTEL, NuSTAR, XMM-Newton, INTEGRAL, EGRET and Fermi. Future searches in experiments such as SKA, JWST, XRISM, Vera C. Rubin Observatory, AMEGO/e-ASTROGAM will allow probing D$a$B and associated axion-photon couplings with unprecedented sensitivity covering a wide range of possible source energies as low as $0.1\,\mu$eV and multiple decades in axion masses. We highlight the differences between astrophysical and dark sector sources of D$a$B. Further, we discuss complementarity with direct detection as well as prospects for other D$a$B searches. Our analysis demonstrates that D$a$B can act as a promising probe of populations of axion emission sources as well as emission mechanisms.

The study of the extreme weather space events is important for a technological dependent society. Extreme Value Theory could be decisive to characterize those extreme events in order to have the knowledge to make decisions in technological, economic and social matters, in all fields with possible impacts. In this work, the hourly values of the Dst geomagnetic index has been studied for the period 1957-2014 using the peaks-over-threshold technique. The shape parameter obtained from the fit of the generalized Pareto distribution to the extreme values of the |Dst| index leads to a negative value implying an upper bound for this time series. This result is relevant, because the estimation of this limit for the extreme values lead to 850 nT as the highest expected value for this geomagnetic index. Thus, from the previous characterization of the Carrington geomagnetic storm and our results, it could be considered the worst case scenario.

Modern hydrodynamic simulations of core-collapse supernovae and neutron-star mergers require knowledge not only of the equilibrium properties of strongly interacting matter, but also of the system's response to perturbations, encoded in various transport coefficients. Using perturbative and holographic tools, we derive here an improved weak-coupling and a new strong-coupling result for the most important transport coefficient of unpaired quark matter, its bulk viscosity. These results are combined in a simple analytic pocket formula for the quantity that is rooted in perturbative Quantum Chromodynamics at high densities but takes into account nonperturbative holographic input at neutron-star densities, where the system is strongly coupled. This expression can be used in the modeling of unpaired quark matter at astrophysically relevant temperatures and densities.

We perform the lattice simulation to estimate the axion dark matter abundance radiated from the global cosmic strings in the post-inflationary scenario. The independent numerical confirmation on the recently observed logarithmic growth in both the number of strings per Hubble patch and the spectral index of the power-law scaling for the axion spectrum is reported. These logarithmic scalings are checked against two different prescriptions for generating initial random field configurations, namely fat-string type and thermal phase transition. We discuss a possible strong correlation between axion spectrum and the string evolutions with different initial conditions to support the insensitivity of scaling behaviors against different initial data and we provide a qualitative understanding of it. The impact of various combinations of the power law of the axion spectrum, nonlinearities around the QCD scale, and average inter-string distances on the axion abundance is discussed. Additionally, we introduce a new novel string identification method, based on the tetrahedralization of the space, which guarantees the connectedness of the strings and provides a convenient way of assigning the core location. Finally we derive the lower bound on the axion mass.

In this paper we study the effects of torsion of space-time in the expansion of the universe as a candidate to dark energy. The analysis is done by reconstructing the torsion function along cosmic evolution by using observational data of Supernovae type Ia and Hubble parameter measurements. We have used a kinematic model for the parameterization of the comoving distance and the Hubble parameter, then the free parameters of the models are constrained by observational data. The reconstruction of the torsion function is obtained directly from the data, using the kinematic parameterizations, and the values for the Hubble parameter and the deceleration parameter are in good agreement to the standard model estimates.