Papers for Thursday, Feb 02 2023

The dearth of planets with sizes around 1.8 $\mathrm{R_\oplus}$ is a key demographic feature discovered by the $Kepler$ mission. Two theories have emerged as potential explanations for this valley: photoevaporation and core-powered mass-loss. However, Rogers et al. (2021) shows that differentiating between the two theories is possible using the three-dimensional parameter space of planet radius, incident flux, and stellar mass. We use homogeneously-derived stellar and planetary parameters to measure the $Kepler$ exoplanet radius gap in this three-dimensional space. We compute the slope of the gap as a function of incident flux at constant stellar mass ($\alpha$ $\equiv$ $\left(\partial \log R_{\mathrm{gap}} / \partial \log S \right)_{M_\star}$) and the slope of the gap as a function of stellar mass at constant incident flux ($\beta$ $\equiv$ $\left(\partial \log R_{\mathrm{gap}} / \partial \log M_\star \right)_{S}$) and find $\alpha$ = 0.069$^{+0.019}_{-0.023}$ and $\beta$ = $-$0.046$^{+0.125}_{-0.117}$. Given that Rogers et al. (2021) shows that core-powered mass-loss predicts $\alpha$ $\approx$ 0.08 and $\beta$ $\approx$ 0.00 while photoevaporation predicts $\alpha$ $\approx$ 0.12 and $\beta$ $\approx$ --0.17, our measurements are more consistent with core-powered mass-loss than photoevaporation. However, we caution that different gap-determination methods can produce systematic offsets in both $\alpha$ and $\beta$; therefore, we motivate a comprehensive re-analysis of $Kepler$ light curves with modern, updated priors on eccentricity and mean stellar density to improve both the accuracy and precision of planet radii and subsequent measurements of the gap.

We report on the discovery of two low-luminosity, broad-line AGN at $z>5$ identified using JWST NIRSpec spectroscopy from the CEERS Survey. We detect broad H$\alpha$ emission from both sources, with FWHM of $2038\pm286$ and $1807\pm207$ km s$^{-1}$, resulting in black hole (BH) masses that are 1-2 dex below that of existing samples of luminous quasars at $z>5$. The first source, CEERS 1670 at $z=5.242$, is 2-3 dex fainter than known quasars at similar redshifts and was previously identified as a candidate low-luminosity AGN based on its rest-frame optical SED. We measure a BH mass of $M_{\rm BH}=1.3\pm0.4\times 10^{7}~M_{\odot}$, confirming that this AGN is powered by the least-massive BH known in the universe at the end of cosmic reionization. The second source, CEERS 3210 at $z=5.624$, is inferred to be a heavily obscured, broad-line AGN caught in a transition phase between a dust-obscured starburst and an unobscured quasar. We estimate its BH mass to be $M_{\rm BH}\simeq 0.9-4.7 \times 10^{7}~M_{\odot}$, depending on the level of dust obscuration assumed. We derive host stellar masses, $M_\star$, allowing us to place constraints on the BH-galaxy mass relationship in the lowest mass range yet probed in the early universe. The $M_{\rm BH}/M_\star$ ratio for CEERS 1670, in particular, is consistent with or higher than the empirical relationship seen in massive galaxies at $z=0$. We examine the emission-line ratios of both sources and find that their location on the BPT and OHNO diagrams is consistent with model predictions for low-metallicity AGN with $Z/Z_\odot \simeq 0.2-0.4$. The spectroscopic identification of low-luminosity, broad-line AGN at $z>5$ with $M_{\rm BH}\simeq 10^{7}~M_{\odot}$ demonstrates the capability of JWST to push BH masses closer to the range predicted for the BH seed population and provides a unique opportunity to study the early stages of BH-galaxy assembly.

In dense stellar clusters like galactic nuclei and globular clusters stellar densities are so high that stars might physically collide with each other. In galactic nuclei the energy and power output can be close, and even exceed, to those from supernovae events. We address the event rate and the electromagnetic characteristics of collisions of main sequence stars (MS) and red giants (RG). We also investigate the case in which the cores form a binary and emit gravitational waves. In the case of RGs this is particularly interesting because the cores are degenerate. We find that MS event rate can be as high as tens per year, and that of RGs one order of magnitude larger. The collisions are powerful enough to mimic supernovae- or tidal disruptions events. We find Zwicky Transient Facility observational data which seem to exhibit the features we describe. The cores embedded in the gaseous debris experience a friction force which has an impact on the chirping mass of the gravitational wave. As a consequence, the two small cores in principle mimic two supermassive black holes merging. However, their evolution in frequency along with the precedent electromagnetic burst and the ulterior afterglow are efficient tools to reveal the impostors. In the particular case of RGs, we derive the properties of the degenerate He cores and their H-burning shells to analyse the formation of the binaries. The merger is such that it can be misclassified with SN Ia events. Because the masses and densities of the cores are so dissimilar in values depending on their evolutionary stage, the argument about standard candles and cosmic ladder should be re-evaluated.

Low-mass X-ray binaries have long been theorised as potential sources of continuous gravitational-wave radiation, yet there is no observational evidence from recent LIGO/Virgo observing runs. Even for the theoretically 'loudest' source, Sco X-1, the upper limit on gravitational-wave strain has been pushed ever lower. Such searches require precise measurements of the source properties for sufficient sensitivity and computational feasibility. Collating over 20 years of high-quality spectroscopic observations of the system, we present a precise and comprehensive ephemeris for Sco X-1 through radial velocity measurements, performing a full homogeneous reanalysis of all relevant datasets and correcting previous analyses. Our Bayesian approach accounts for observational systematics and maximises not only precision, but also the fidelity of uncertainty estimates - crucial for informing principled continuous-wave searches. Our extensive dataset and analysis also enables us to construct the highest signal-to-noise, highest resolution phase-averaged spectrum of a low-mass X-ray binary to date. Doppler tomography reveals intriguing transient structures present in the accretion disk and flow driven by modulation of the accretion rate, necessitating further characterisation of the system at high temporal and spectral resolution. Our ephemeris corrects and supersedes previous ephemerides, and provides a factor three reduction in the number of templates in the search space, facilitating precision searches for continuous gravitational-wave emission from Sco X-1 throughout the upcoming LIGO/Virgo/KAGRA O4 observing run and beyond.

Increasing observations of white dwarf atmospheric pollution and disrupting planetesimals is driving increased studies into the fate of exo-asteroids around post-main-sequence stars. Planetesimal populations in the Solar System which are most likely to survive the violent post-main-sequence evolution, such as the Kuiper Belt, display a large binary fraction with a propensity for near equal-mass components and provide a previously unexplored population of planetesimals which are likely to exist around white dwarfs. Here we simulate the dynamical evolution of equal-mass binary asteroid systems around white dwarfs using the N-body integrator REBOUND for 1 Gyr. We confirm that giant planets are efficient at dissociating and ejecting binary asteroid systems on eccentric orbits, while Earth-mass planets are better at keeping planetesimals in their planetary systems. We find binary systems can be dissociated and ejected from their systems across Myr timescales, producing interstellar objects. We do not expect a population of free-floating binary asteroid systems as all ejected planetesimals are gravitationally unbound from each other. Further, we discuss the influence of asteroid binarity on the white dwarf pollution process and find there is little to no impact on how close a body can get to a star. However, the orbital evolution of binary asteroids changes the distribution of planetesimals available in a white dwarf planetary system to be further scattered onto white dwarf polluting orbits.

We use 28 quasar fields with high-resolution (HIRES and UVES) spectroscopy from the MUSE Analysis of Gas Around Galaxies survey to study the connection between Ly${\alpha}$ emitters (LAEs) and metal-enriched ionized gas traced by CIV in absorption at redshift $z\approx3-4$. In a sample of 220 CIV absorbers, we identify 143 LAEs connected to CIV gas within a line-of-sight separation ${\rm \pm 500\,km\,s^{-1}}$, equal to a detection rate of $36\pm 5$ per cent once we account for multiple LAEs connected to the same CIV absorber. The luminosity function of LAEs associated with CIV absorbers shows a $\approx 2.4$ higher normalization factor compared to the field. CIV with higher equivalent width and velocity width are associated with brighter LAEs or multiple galaxies, while weaker systems are less often identified near LAEs. The covering fraction in groups is up to $\approx 3$ times larger than for isolated galaxies. Compared to the correlation between optically-thick HI absorbers and LAEs, CIV systems are twice less likely to be found near LAEs especially at lower equivalent width. Similar results are found using SiIV as tracer of ionized gas. We propose three components to model the gas environment of LAEs: i) the circumgalactic medium of galaxies, accounting for the strongest correlations between absorption and emission; ii) overdense gas filaments connecting galaxies, driving the excess of LAEs at a few times the virial radius and the modulation of the luminosity and cross-correlation functions for strong absorbers; iii) an enriched and more diffuse medium, accounting for weaker CIV absorbers farther from galaxies.

Small integration timesteps for a small fraction of short-timescale regions are bottlenecks for high-resolution galaxy simulations using massively parallel computing. This is an urgent issue that needs to be resolved for future higher-resolution galaxy simulations. One possible solution is to use an (approximate) Hamiltonian splitting method, in which only regions requiring small timesteps are integrated with small timesteps, separated from the entire galaxy. In particular, gas affected by supernova (SN) explosions often requires the smallest timestep in such a simulation. To apply the Hamiltonian splitting method to the particles affected by SNe in a smoothed-particle hydrodynamics simulation, we need to identify the regions where such SN-affected particles reside during the subsequent global step (the integration timestep for the entire galaxy) in advance. In this paper, we developed a deep learning model to predict a shell expansion after a SN explosion and an image processing algorithm to identify SN-affected particles in the predicted regions. We found that we can identify more than 95 per cent of the target particles with our method, which is a better identification rate than using an analytic approach with the Sedov-Taylor solution. Combined with the Hamiltonian splitting method, our particle selection method using deep learning will improve the performance of galaxy simulations with extremely high resolution.

Ultra-stripped supernovae are different from other terminal explosions of massive stars, as they show little or no ejecta from the actual supernova event. They are thought to occur in massive binary systems after the exploding star has lost its surface through interactions with its companion. Such supernovae produce little to no kick, leading to the formation of a neutron star without loss of the binary companion, which itself may also evolve into another neutron star. Here we show that a recently discovered high-mass X-ray binary, CPD -29 2176 (CD -29 5159; SGR 0755-2933), has an evolutionary history that shows the neutron star component formed during an ultra-stripped supernova. The binary has orbital elements that are similar both in period and in eccentricity to one of 14 Be X-Ray binaries that have both known orbital periods and eccentricities. The identification of the progenitors systems for ultra-stripped supernovae is necessary as their evolution pathways leads to the formation of a binary neutron star systems. Binary neutron stars, such as the system that produced the kilonova GW170817 that was observed with both electromagnetic and gravitational energy, are known to produce a large quantity of heavy elements.

We study the dynamics of cold molecular gas in two main-sequence galaxies at cosmic noon (zC-488879 at $z\simeq1.47$ and zC-400569 at $z\simeq2.24$) using new high-resolution ALMA observations of multiple $^{12}$CO transitions. For zC-400569 we also re-analyze high-quality H$\alpha$ data from the SINS/zC-SINF survey. We find that (1) Both galaxies have regularly rotating CO disks and their rotation curves are flat out to $\sim$8 kpc contrary to previous results pointing to outer declines in the rotation speed $V_{\rm rot}$; (2) The intrinsic velocity dispersions are low ($\sigma_{\rm CO}\lesssim15$ km/s for CO and $\sigma_{\rm H\alpha}\lesssim37$ km/s for H$\alpha$) and imply $V_{\rm rot}/\sigma_{\rm CO}\gtrsim17-22$ yielding no significant pressure support; (3) Mass models using HST images display a severe disk-halo degeneracy: models with inner baryon dominance and models with "cuspy" dark matter halos can fit the rotation curves equally well due to the uncertainties on stellar and gas masses; (4) Milgromian dynamics (MOND) can successfully fit the rotation curves with the same acceleration scale $a_0$ measured at $z\simeq0$. The question of the amount and distribution of dark matter in high-$z$ galaxies remains unsettled due to the limited spatial extent of the available kinematic data; we discuss the suitability of various emission lines to trace extended rotation curves at high $z$. Nevertheless, the properties of these two high-$z$ galaxies (high $V_{\rm rot}/\sigma_{\rm V}$ ratios, inner rotation curve shapes, bulge-to-total mass ratios) are remarkably similar to those of massive spirals at $z\simeq0$, suggesting weak dynamical evolution over more than 10 Gyr of the Universe's lifetime.

The Milky Way halo is one of the few galactic haloes that provides a unique insight into galaxy formation by resolved stellar populations. Here, we present a catalogue of $\sim$47 million halo stars selected independent of parallax and line-of-sight velocities, using a combination of Gaia DR3 proper motion and photometry by means of their reduced proper motion. We select high tangential velocity (halo) main sequence stars and fit distances to them using their simple colour-absolute-magnitude relation. This sample reaches out to $\sim$21 kpc with a median distance of $6.6$ kpc thereby probing much further out than would be possible using reliable Gaia parallaxes. The typical uncertainty in their distances is $0.57_{-0.26}^{+0.56}$ kpc. Using the colour range $0.45<(G_0-G_\mathrm{RP,0})<0.715$ where the main sequence is narrower, gives an even better accuracy down to $0.39_{-0.12}^{+0.18}$ kpc in distance. The median velocity uncertainty for stars within this colour range is 15.5 km/s. The distribution of these sources in the sky, together with their tangential component velocities, are very well-suited to study retrograde substructures. We explore the selection of two complex retrograde streams: GD-1 and Jhelum. For these streams, we resolve the gaps, wiggles and density breaks reported in the literature more clearly. We also illustrate the effect of the kinematic selection bias towards high proper motion stars and incompleteness at larger distances due to Gaia's scanning law. These examples showcase how the full RPM catalogue made available here can help us paint a more detailed picture of the build-up of the Milky Way halo.

In-ice radio detectors are a promising tool for the discovery of EeV neutrinos. For astrophysics, the implications of such a discovery will rely on the reconstruction of the neutrino arrival direction. This paper describes a first complete neutrino arrival direction reconstruction for detectors employing deep antennas such as RNO-G or planning to employ them like IceCube-Gen2. We will didactically introduce the challenges of neutrino direction reconstruction using radio emission in ice, elaborate on the detail of the algorithm used, and describe the obtainable performance based on a simulation study and discuss its implication for astrophysics.

Context: With the recent surge of planetary surveys focusing on detecting Earth-mass planets around M dwarfs, it is becoming more important to understand chromospheric activity in M dwarfs. Stellar chromospheric calcium emission is typically measured using the $R'_\mathrm{HK}$ calibrations of Noyes et al. (1984), which are only valid for $0.44 \le B-V \le 0.82$. Measurements of calcium emission for cooler dwarfs $B-V \ge 0.82$ are difficult because of their intrinsic dimness in the blue end of the visible spectrum. Aims: We measure the absolute Ca II HK and H$\alpha$ flux of a sample of 110 HARPS M dwarfs and also extend the calibration of $R'_\mathrm{HK}$ to the M dwarf regime using PHOENIX stellar atmosphere models. Methods: We normalized a template spectrum with a high signal-to-noise ratio that was obtained by coadding multiple spectra of the same star to a PHOENIX stellar atmosphere model to measure the chromospheric Ca II HK and H$\alpha$ flux in physical units. We used three different $T_\mathrm{eff}$ calibrations and investigated their effect on Ca II HK and H$\alpha$ activity measurements. We performed conversions of the Mount Wilson S index to $R'_\mathrm{HK}$ as a function of effective temperature for the range 2300 K $\le T_\mathrm{eff} \le$ 7200 K. Last, we calculated continuum luminosity $\chi$ values for Ca II HK and H$\alpha$ in the same manner as West & Hawley (2008) for $-1.0 \le \mathrm{Fe/H} \le +1.0$ in steps of $\Delta \mathrm{Fe/H} = 0.5$. Results: We compare different $T_\mathrm{eff}$ calibrations and find $\Delta T_\mathrm{eff} \sim$ several 100 K for mid- to late-M dwarfs. Using these different $T_\mathrm{eff}$ calibrations, we establish a catalog of $\log R'_\mathrm{HK}$ and $\mathcal{F}'_\mathrm{H\alpha}/\mathcal{F}_\mathrm{bol}$ measurements for 110 HARPS M dwarfs. [abridged]

Addressing the discrepancy between the late and early time measurements of the Hubble parameter, $H_0$, and the so-called $S_8$ parameter has been a challenge in precision cosmology. Several models are present to address these tensions, but very few of them can do so simultaneously. In the past, we have suggested Banks-Zaks/Unparticles as an emergent Dark Energy model and claimed that it can ameliorate the Hubble tension. In this work, we test this claim and perform a likelihood analysis of the model and its parameters are given current data and compare it to $\Lambda$CDM. The model offers a possible resolution of Hubble tension and softens the Large Scale Structure (LSS) tension without employing a scalar field or modifying the gravitational sector. Our analysis shows a higher value of $H_0 \sim 70 - 73$ km/sec/Mpc and a slightly lower value of $S_8$ for various combinations of data sets. Consideration of Planck CMB data combined with the Pantheon sample and SH0ES priors lowers the $H_0$ and $S_8$ tension to $0.96 \sigma$ and $0.94 \sigma$ respectively with best-fit $\Delta \chi^2 \approx -10$ restoring cosmological concordance. Significant improvement in the likelihood persists for other combinations of data sets as well. Evidence for the model is given by inferring one of its parameters to be $x_0\simeq-4.36$.

We report spectral and polarimeter observations of two weak, low frequency (${\approx}$85-60\,MHz) solar coronal type II radio bursts that occurred on 2020 May 29 within a time interval ${\approx}$2\,min. The bursts had fine structures, and were due to harmonic plasma emission. Our analysis indicates that the magnetohydrodynamic (MHD) shocks responsible for the 1st and 2nd type II bursts were generated by the leading edge (LE) of an extreme-ultraviolet (EUV) flux rope/coronal mass ejection (CME) and interaction of its flank with a neighbouring coronal structure, respectively. The CME deflected from the radial direction by ${\approx}25^{\arcdeg}$ during propagation in the near-Sun corona. The estimated power spectral density (PSD) and magnetic field strength ($B$) near the location of the 1st burst at heliocentric distance $r{\approx}1.35R_{\odot}$ are $\rm {\approx}2{\times}10^{-3}\,W^{2}m$ and ${\approx}$1.8\,G, respectively. The corresponding values for the 2nd burst at the same $r$ are $\rm {\approx}10^{-3}\,W^{2}m$ and ${\approx}$0.9\,G. The significant spatial scales of the coronal turbulence at the location of the two type II bursts are ${\approx}$62\,-\,1\,Mm. Our conclusions from the present work are that the turbulence and magnetic field strength in the coronal region near the CME LE are higher compared to the corresponding values close to its flank. The derived estimates of the two parameters correspond to the same $r$ for both the CME LE and its flank, with a delay of ${\approx}$2\,min for the latter.

Sonification as a complement of visualization is been under research for decades as a new ways of data deployment. ICAD conferences, gather together specialists from different disciplines to discuss about sonification. Different tools as sonoUno, starSound and Web Sandbox are attempt to reach a tool to open astronomical data sets and sonify it in conjunction to visualization. In this contribution, the sonoUno web version is presented, this version allows user to explore data sets without any installation. The data can be uploaded or a pre-loaded file can be opened, the sonification and the visual characteristics of the plot can be customized on the same window. The plot, sound and marks can be saved. The web interface were tested with the main used screen readers in order to confirm their good performance.

Even when actual technologies present the potential to augment inclusion and the United Nations has been stablished the digital access to information as a human right, people with disabilities continuously faced barriers in their profession. In many cases, in sciences, the lack of accessible and user centred tools left behind researches with disabilities and not facilitate them to conduct front-line research by using their respective strengths. In this contribution, we discuss some hurdles and solutions relevant for using new technology for data analysis, analysing the barriers found by final users. A focus group session was conducted with nine people with and without visual impairment, using the tool sonoUno with one linear function and an astronomical data set downloaded from the Sloan Digital Sky Survey. As a result of the focus group study, incorporating data analysis using sonification, we conclude that functionally diverse people require tools to be autonomous, thereby enabling precision, certainty, effectiveness and efficiency in their work, resulting in enhanced equity. This can be achieved by pursuing a user-centred design approach as integral to software development, and by adapting resources according to the research objectives. Development of tools that empower people with wide-ranging abilities to not only access data using multi-sensorial techniques, but also address the current lack of inclusion, is sorely needed.

Space-based gamma-ray telescopes such as the Fermi Large Area Telescope have used single sided silicon strip detectors to measure the position of charged particles produced by incident gamma rays with high resolution. At energies in the Compton regime and below, two dimensional position information within a single detector is required. Double sided silicon strip detectors are one option; however, this technology is difficult to fabricate and large arrays are susceptible to noise. This work outlines the development and implementation of monolithic CMOS active pixel silicon sensors, AstroPix, for use in future gamma-ray telescopes. Based upon detectors designed using the HVCMOS process at the Karlsruhe Institute of Technology, AstroPix has the potential to maintain the high energy and angular resolution required of a medium-energy gamma-ray telescope while reducing noise with the dual detection-and-readout capabilities of a CMOS chip. The status of AstroPix development and testing as well as outlook for application in future telescopes is presented.

The chemical composition of gas in galaxies can be measured in detail from absorption spectroscopy. By studying gas in galaxies in this way, it is possible to investigate the small and faint galaxies, which are the most numerous in the universe. In particular, the chemical distribution of gas in absorbing systems gives us insight into cycles of gas in and around galaxies. Here we study chemical enrichment within 64 Damped Lyman-alpha Absorption (DLA) systems between $1.7 < z < 4.2$. We use high-resolution spectra from VLT/UVES to infer dust depletion from relative abundances of several metals. We perform a component-by-component analysis within DLAs, and characterise variations in their chemical enrichment. Unlike hydrogen, the metal columns can be characterised for individual components. We use them to derive the dust depletion ([Zn/Fe]fit), as an indicator for chemical enrichment. We find that some DLAs are chemically diverse within themselves, with [Zn/Fe]fit ranging up to 0.62 dex within a single system. This suggests that absorbing gas within these galaxies is chemically diverse. Although we do not find a clear trend of decreasing dust depletion with redshift, we do see that the most chemically enriched systems are at lower redshifts. We also observe evidence for dust-poor components at all redshifts, which may be due to the accretion of pristine gas onto galaxies. We combine the chemical and kinematic properties of the individual gas components and observe potential signatures of infalling gas, with low depletion at velocities below $\sim$100km/s, and outflows, with high depletion and velocities of $\sim$600km/s. We find over-abundances of alpha-elements (an enhancement of $\sim$0.3dex) and under-abundances of Mn in several components, which is likely a signature of core-collapse SNe nucleosythesis in the ISM. We observe these effects mostly at lower levels of chemical enrichment.

We perform a series of numerical simulations to recreate small-scale two-fluid jets using the JOANNA code, considering the magnetohydrodynamics of two fluids (ions + electrons and neutral particles). We first excite the jets in a uniform magnetic field by using velocity pulse perturbations located at $y_{0}=$1.3, 1.5, and 1.8 Mm, considering the base of the photosphere at $y=0$ Mm. Then, we repeat the excitation of the jets in a magnetic field that mimics a flux tube. Mainly, the jets excited at the upper chromosphere ($y\sim1.8$ Mm) reach lower heights than those excited at the lower chromosphere ($y\sim1.3$ Mm); this is due to the higher initial vertical location because of the lesser amount of plasma dragging. In both scenarios, the dynamics of the neutral particles and ions show similar behavior; however, we can still identify some differences in the velocity drift, which in our simulations is of the order of $10^{-3}$ km s$^{-1}$ at the tips of the jets once they reached their maximum heights. Also, we estimate the heat generation due to the friction between ions and neutrals ($Q^{in}_{i,n}$), which is of the order of $0.002-0.06$ W m$^{-3}$; however it is small to contribute to the heating of the surroundings of the solar corona. The jets in the two magnetic environments do not show substantial differences other than a slight variation in the maximum heights reached, particularly in the uniform magnetic field scenario. Finally, the maximum heights reached by the three different jets are in the range of some morphological parameters corresponding to macrospicules, Type I spicules, and Type II spicules.

Low mass galaxies in the Local Group are dominated by dark matter and comprise the well studied ``dwarf Spheroidal" (dSph) class, with typical masses of $10^{9-10}M_\odot$ and also the equally numerous ``ultra faint dwarfs" (UFD), discovered recently, that are distinctly smaller and denser with masses of only $10^{7-8}M_\odot$. This bimodality amongst low mass galaxies contrasts with the scale free continuity expected for galaxies formed under gravity, as in the standard Cold Dark Matter (CDM) model for heavy particles. Within each dwarf class we find the core radius $R_c$ is inversely related to velocity dispersion $\sigma$, quite the opposite of standard expectations, but indicative of dark matter in a Bose-Einstein state, where the Uncertainty Principle requires $R_c \times \sigma$ is fixed by Planks constant, $h$. The corresponding boson mass, $m_b=h/R_c \sigma$, differs by one order of magnitude between the UDF and dSph classes, with $10^{-21.4}$eV and $10^{-20.3}$eV respectively. Two boson species is reinforced by parallel relations seen between the central density and radius of UDF and dSph dwarfs respectively, each matching the steep prediction, $\rho_c \propto R_c^{-4}$, for soliton cores in the ground state. Furthermore, soliton cores accurately fit the stellar profiles of UDF and dSph dwarfs where prominent, dense cores appear surrounded by low density halos, as predicted by our simulations. Multiple bosons may point to a String Theory interpretation for dark matter, where a discrete mass spectrum of axions is generically predicted to span many decades in mass, offering a unifying "Axiverse" interpretation for the observed "diversity" of dark matter dominated dwarf galaxies.

The stability criteria of rapid mass transfer and common envelope evolution are fundamental in binary star evolution. They determine the mass, mass ratio and orbital distribution of many important systems, such as X-ray binaries, Type Ia supernovae and merging gravitational wave sources. We use our adiabatic mass-loss model to systematically survey the intermediate-mass stars' thresholds for dynamical-timescale mass transfer. The impact of metallicity on the stellar responses and critical mass ratios is explored. Both tables ($Z=0.001$) and fitting formula ($Z=0.001$ and $Z=0.02$) of critical mass ratios of intermediate-mass stars are provided. An application of our results to intermediate-mass X-ray binaries (IMXBs) is discussed. We find that the predicted upper limit to mass ratios, as a function of orbital period, is consistent with the observed IMXBs that undergo thermal or nuclear timescale mass transfer. According to the observed peak X-ray luminosity $L_\mathrm{X}$, we predict the range of $L_\mathrm{X}$ for IMXBs as a function of the donor mass and the mass transfer timescale.

Tsinghua University-Ma Huateng Telescopes for Survey (TMTS) aims to detect fast-evolving transients in the Universe, which has led to the discovery of thousands of short-period variables and eclipsing binaries since 2020. In this paper, we present the observed properties of 125 flare stars identified by the TMTS within the first two years, with an attempt to constrain their eruption physics. As expected, most of these flares were recorded in late-type red stars with G_BP-G_RP > 2.0 mag, however, the flares associated with bluer stars tend to be on average more energetic and have broader profiles. The peak flux (F_peak) of the flare is found to depend strongly on the equivalent duration (ED) of the energy release, i.e., F_peak \propto ED^{0.72 \pm 0.04}, which is consistent with results derived from the Kepler and Evryscope samples. This relation is likely related to the magnetic loop emission, while -- for the more popular non-thermal electron heating model -- a specific time evolution may be required to generate this relation. We notice that flares produced by hotter stars have a flatter F_peak \propto ED relation compared to that from cooler stars. This is related to the statistical discrepancy in light-curve shape of flare events with different colors. In spectra from LAMOST, we find that flare stars have apparently stronger H alpha emission than inactive stars, especially at the low temperature end, suggesting that chromospheric activity plays an important role in producing flares. On the other hand, the subclass having frequent flares are found to show H alpha emission of similar strength in their spectra to that recorded with only a single flare but similar effective temperature, implying that the chromospheric activity may not be the only trigger for eruptions.

The origin and radiation mechanisms of high energy emissions from pulsars have remained mysterious since their discovery. Here we report, based on a sample of 68 pulsars, observational connection of non-thermal X-ray emissions from pulsars with their timing properties and thermal emissions, which may provide some constraints on theoretical modeling. Besides strong correlations with the spin-down power $\dot{E}$ and the magnetic field strength at the light cylinder $B_{\rm lc}$, the non-thermal X-ray luminosity in 0.5 - 8 keV, $L_{\rm p}$, represented by the power-law component in the spectral model, is found to be strongly correlated with the highest possible electric field strength in the polar gap, $E_{\rm pc}$, of the pulsar. The spectral power index $\Gamma_{\rm p}$ of that power-law component is also found, for the first time in the literature, to strongly correlate with $\dot{E}$, $B_{\rm lc}$ and $E_{\rm pc}$, thanks to the large sample. In addition, we found that $L_{\rm p}$ can be well described by $L_{\rm p}\propto T^{5.96\pm 0.64}R^{2.24\pm 0.18}$, where $T$ and $R$ are the surface temperature and the emitting-region radius of the surface thermal emission, represented by the black-body component in the spectral model. $\Gamma_{\rm p}$, on the other hand, can be well described only when timing variables are included, and the relation is $\Gamma_{\rm p} = \log(T^{-5.8\pm 1.93}R^{-2.29\pm 0.85}P^{-1.19\pm 0.88}\dot{P}^{0.94\pm 0.44})$ plus a constant. These relations strongly suggest the existence of connections between surface thermal emission and electron-positron pair production in pulsar magnetospheres.

In this paper, we report the multiwavelength observations of an erupting prominence and the associated CME on 13 May 2013. The event occurs behind the western limb in the field of view of SDO/AIA. The prominence is supported by a highly twisted magnetic flux rope and shows rapid rotation in the counterclockwise direction during the rising motion. The rotation of the prominence lasts for $\sim$47 minutes. The average period, angular speed, and linear speed are $\sim$806 s, $\sim$0.46 rad min$^{-1}$, and $\sim$355 km s$^{-1}$, respectively. The total twist angle reaches $\sim$7$\pi$, which is considerably larger than the threshold for kink instability. Writhing motion during 17:42$-$17:46 UT is clearly observed by SWAP in 174 {\AA} and EUVI on board the behind STEREO spacecraft in 304 {\AA} after reaching an apparent height of $\sim$405\,Mm. Therefore, the prominence eruption is most probably triggered by kink instability. A pair of conjugate flare ribbons and post-flare loops are created and observed by STA/EUVI. The onset time of writhing motion is consistent with the commencement of the impulsive phase of the related flare. The 3D morphology and positions of the associated CME are derived using the graduated cylindrical shell (GCS) modeling. The kinetic evolution of the reconstructed CME is divided into a slow-rise phase ($\sim$330 km s$^{-1}$) and a fast-rise phase ($\sim$1005 km s$^{-1}$) by the writhing motion. The edge-on angular width of the CME is a constant (60$^{\circ}$), while the face-on angular width increases from 96$^{\circ}$ to 114$^{\circ}$, indicating a lateral expansion. The latitude of the CME source region decreases slightly from $\sim$18$^{\circ}$ to $\sim$13$^{\circ}$, implying an equatorward deflection during propagation.

Kilonovae are approximately thermal transients, produced by mergers of binary neutron stars (BNSs) and NS-black hole binaries. As the optical counterpart of gravitational-wave event GW170817, AT2017gfo is the first kilonova detected with smoking-gun evidence. Its observation offers vital information for constraining the Hubble constant, the source of Galactic $r$-process enrichment, and the equations of state of neutron stars. The 2.5-meter Wide-Field Survey Telescope (WFST) operates at six bands (u, g, r, i, z, w), spanning from 320 to 925 nm. It will be completed in the first half of 2023, and with a field-of-view diameter of 3 degrees, aims to detect kilonovae in the near future. In this article, considering the influence of the host galaxies and sky brightness, we generate simulated images to investigate WFST's ability to detect AT2017gfo-like kilonovae. Due to their spectra, host galaxies can significantly impact kilonova detection at a longer wavelength. When kilonovae are at peak luminosity, we find that WFST performs better in g- and r-bands and can detect 90\% (50\%) kilonovae at a luminosity distance of 248 Mpc (338 Mpc) with 30 s exposures. Furthermore, to reflect actual efficiency under target-of-opportunity observations, we calculate the total time of follow-up under various localization areas and distances. We find that if the localization areas of most BNS events detected during O4 are hundreds of square degrees, WFST is expected to roughly find 30\% kilonovae in the first two nights each year during O4 period.

SMC X-1 is a high-mass X-ray binary showing superorbital modulation with an unstable period. Previous monitoring shows three excursion events in 1996--1998, 2005--2007, and 2014--2016. The superorbital period drifts from >60 days to <40 days and then evolves back during an excursion. Here we report a new excursion event of SMC X-1 in 2020--2021, indicating that the superorbital modulation has an unpredictable, chaotic nature. We trace the spin-period evolution and find that the spin-up rate accelerated one year before the onset of this new excursion, which suggests a possible inside-out process connecting the spin-up acceleration and the superorbital excursion. This results in a deviation of the spin period residual, similar to the behaviour of the first excursion in 1996--1998. In further analysis of the pulse profile evolution, we find that the pulsed fraction shows a long-term evolution and may be connected to the superorbital excursion. These discoveries deepen the mystery of SMC X-1 because they cannot be solely interpreted by the warped disc model. Upcoming pointed observations and theoretical studies may improve our understanding of the detailed accretion mechanisms taking place.

We investigate how the dust temperature is affected by local environmental quantities, especially dust surface density ($\Sigma_\mathrm{dust}$), dust-to-gas ratio (D/G) and interstellar radiation field. We compile multi-wavelength observations in 46 nearby galaxies, uniformly processed with a common physical resolution of $2~$kpc. A physical dust model is used to fit the infrared dust emission spectral energy distribution (SED) observed with WISE and Herschel. The star formation rate (SFR) is traced with GALEX ultraviolet data corrected by WISE infrared. We find that the dust temperature correlates well with the SFR surface density ($\Sigma_{\rm SFR}$), which traces the radiation from young stars. The dust temperature decreases with increasing D/G at fixed $\Sigma_{\rm SFR}$ as expected from stronger dust shielding at high D/G, when $\Sigma_\mathrm{SFR}$ is higher than $\sim 2\times 10^{-3}~\rm M_\odot~yr^{-1}~kpc^{-2}$. These measurements are in good agreement with the dust temperature predicted by our proposed analytical model. Below this range of $\Sigma_\mathrm{SFR}$, the observed dust temperature is higher than the model prediction and is only weakly dependent on D/G, which is possibly due to the dust heating from old stellar population or the variation of SFR within the past $10^{10}~$yr. Overall, the dust temperature as a function of $\Sigma_\mathrm{SFR}$ and $\Sigma_\mathrm{dust}$ predicted by our analytical model is consistent with observations. We also notice that at fixed gas surface density, $\Sigma_{\rm SFR}$ tends to increase with D/G, i.e. we can empirically modify the Kennicutt-Schmidt law with a dependence on D/G to better match observations.

Precision antenna calibration is required for mitigating the impact of foreground contamination in 21 cm cosmological radio surveys. One widely studied source of error is the effect of missing point sources in the calibration sky model; however, poorly understood diffuse galactic emission also creates a calibration bias that can complicate the clean separation of foregrounds from the 21 cm signal. In this work, we present a technique for suppressing this bias with temporal filtering of radio interferometric visibilities observed in a drift-scan mode. We demonstrate this technique on mock simulations of the Hydrogen Epoch of Reionization Array (HERA) experiment. Inspecting the recovered calibration solutions, we find that our technique reduces spurious errors by over an order of magnitude. This improved accuracy approaches the required accuracy needed to make a fiducial detection of the 21 cm signal with HERA, but is dependent on a number of external factors that we discuss. We also explore different types of temporal filtering techniques and discuss their relative performance and tradeoffs.

We report analysis using the James Webb Space Telescope (JWST) to identify a candidate progenitor star of the Type II-plateau supernova SN 2022acko in the nearby, barred spiral galaxy NGC 1300. To our knowledge, our discovery represents the first time JWST has been used to localize a progenitor system in pre-explosion archival Hubble Space Telescope (HST) images. We astrometrically registered a JWST NIRCam image from 2023 January, in which the SN was serendipitously captured, to pre-SN HST F160W and F814W images from 2017 and 2004, respectively. A star corresponding precisely to the SN position has been isolated with reasonable confidence, although a ~2.9 sigma difference exists between the measured position for the star from HST and the transformed SN position from JWST. That star has a spectral energy distribution and overall luminosity consistent with a single-star model having an initial mass somewhat less than the canonical 8 Msun theoretical threshold for core collapse, although the star's initial mass is inconsistent with that of a super-asymptotic giant branch star which might be a forerunner of an electron-capture SN. The properties of the progenitor alone imply that SN 2022acko is a relatively normal SN II-P, albeit most likely a low-luminosity one. The progenitor candidate should be confirmed with follow-up HST imaging at late times, when the SN has sufficiently faded. This potential use of JWST opens a new era of identifying SN progenitor candidates at high spatial resolution.

Understanding the collisional outcomes of dust aggregates and dependence on material properties of the constituting particles is of great importance toward understanding planet formation. Recent numerical simulations have revealed that interparticle tangential friction plays a crucial role in energy dissipation during collisions between porous dust aggregates; however, the importance of friction on the collisional growth of dust aggregates remains poorly understood. Here we demonstrate the effects of interparticle tangential friction on the collisional growth of dust aggregates. We performed numerical simulations of collisions between equal-mass porous dust aggregates consisting of cohesive and frictionless spheres. We changed the collision velocity and impact angle systematically and calculated the collisional growth efficiency as a function of the collision velocity. We found that the threshold velocity for collisional growth decreases when dust aggregates are made of frictionless spheres as compared to frictional spheres. Our results highlight the importance of tangential interactions on the collisional behavior of dust aggregates and indicate that the predictive equation for threshold velocity should be reconstructed.

The newly installed CALLISTO spectrometer, hosted by the Department of Space Environment, Institute of Basic and Applied Sciences- EJUST, commenced operation on August 14, 2021. The system contains a cross dipole long-wavelength array antenna with high sensitivity to monitor solar radio transients. Its antenna was strategically positioned and appeared to be in the center of the CALLISTO network of spectrometers. Moreover, in the northern section of Africa, the Egypt-Alexandria CALLISTO and ALGERIA-CRAAG stations are the only ones operating. There are no stations in the West African region, while stations in the eastern part of Africa are not working. Thus, Egypt- Alexandria station serves as a reference for other stations within the e-CALLISTO network. Despite the low solar activity, the instrument detected several solar radio bursts not limited to type II, type III, and type V. A vigorous case study was conducted on two selected radio burst events to validate the authenticity of the recorded events. Other solar radio stations at different geographical locations recorded all the radio bursts detected by the spectrometer. The case study included brief analyses that indicated a type II radio burst observed on October 09, 2021, between 06:30 and 07:00 UT, was associated with an M1.6 solar flare located at N18E08 within NOAA-AR 12882 and a CME with a shock front speed of ~978 km/s. However, the type III radio burst is neither CME nor solar flare associated. These analyses examine the instrument's capacity to provide real-time solar radio transient data 24 hours a day to mitigate the challenges of data gaps faced in the African continent. Hence, the instrument has become an integral part of space weather monitoring and forecasting over the region and other parts of the globe.

We use an asteroseismology method to calculate the frequencies of gravitational waves in a long-term core-collapse supernova simulation, with a mass of 9.6 $M_\odot$. The simulation, which includes neutrino transport in general relativity is performed from core-collapse, bounce, explosion and cooling of protoneutron stars (PNSs) up to 20 s after the bounce self-consistently. Based on the hydrodynamics background, we calculate eigenmodes of the PNS oscillation through a perturbation analysis on fluid and metric. We classify the modes by the number of nodes and find that there are several eigenmodes. In the early phase before 1 s, there are a low-frequency g-mode around 0.5 kHz, a mid-frequency f-modes around 1 kHz, and high-frequency p-modes above them. Beyond 1 s, the g-modes drop too low in frequency and the p-modes become too high to be detected by ground-based interferometers. However, the f-mode persists at 1 kHz. We present a novel fitting formula for the ramp-up mode, comprising a mixture of g-mode and f-mode, using postbounce time as a fitting parameter. Our approach yields improved results for the long-term simulation compared to prior quadratic formulas. We also fit frequencies using combinations of gravitational mass and radius of the PNS. We test three types of fitting variables: compactness, surface gravity, and average density. We present results of the time evolution of each mode and the fitting for three different ranges, from 0.2 to 1, 4, and 20 s for each formula. We compare the deviation of the formulas from the eigenmodes to determine which fitting formula is the best. In conclusion, any variable fits the eigenmodes well to a similar degree. Comparing 3 variables in detail, the fitting with compactness is slightly the best among them. We also find that the fitting using less than 1 s of simulation data cannot be extrapolated to the long-term frequency prediction.

We use extensive model grids to estimate the global parameters of four partially-eclipsing W UMa contact binaries near the period cutoff. All four systems consist of K-type main sequence primaries and M-type secondaries that appear undersized and underluminous for their masses because of the energy transfer through the common envelope. Three of the four stars exhibit light curve asymmetry that is explained in terms of magnetic activity and modeled with dark spots. We discuss the reliability of the photometric mass ratios and derived absolute parameters in context of total or partial eclipses and compare them with a sample of totally-eclipsing short-period W UMa systems from the literature.

We report on the discovery of a rare case of spatially and kinematically resolved galactic scale outflow at intermediate redshift, based on VLT/MUSE optical integral field spectroscopic observation of the quasar HE 0238$-$1904. This classical non-broad absorption line (non-BAL) quasar at $z=0.631$ remains underexplored in its optical emission lines, though its UV absorption lines are well-studied. We identify a superbubble driven by HE 0238$-$1904 from the emission line morphology, line ratio diagnostics and kinematics, showing a one-sided outflow reaching a projected distance of $R \sim 55$ kpc from the nucleus. The bulk of the ionized gas, with a characteristic mass $M \sim 10^{8}~\rm M_{\odot}$, is blueshifted by $v \approx 700$ km s$^{-1}$ with respect to the quasar systemic velocity. The outflows detected using absorption line and the emission line are likely stratified components of different spatial scale and velocity in the ionized phase outflow. Although feedback in HE 0238$-$1904 is taking place on kpc scale, the kinetic power of the outflow at 55 kpc ($\ll 0.1\% L_{bol}$) implies that it is inadequate to regulate effectively the evolution of the host galaxy at this large scale.

We present a multi-wavelength study of the active nucleus and the off-nuclear X-ray sources in the nearby spiral galaxy, NGC 1365 using three simultaneous UV/X-ray observations by AstroSat over a two months period and archival IR observations performed with Spitzer and Herschel. Utilising the data from the Soft X-ray Telescope (SXT) on-board AstroSat, we find spectral variability mainly caused by the variation in the X-ray column density, (N$_H$ $\sim$ 10$^{22}$ - 10$^{23}$ cm$^{-2}$). With the accurate spatial resolution of the UVIT onboard AstroSat, we separate the intrinsic AGN flux from the host galaxy emission and then correct for the Galactic and the internal reddening. We detect no significant variation in the NUV emission over the observation period. The AGN in FUV band is undetectable due to heavy intrinsic extinction. Further, the multi-wavelength IR/UV/X-ray AGN SED reveals that the AGN is in a low luminosity phase with accretion rate $\sim$ 0.01 L$_{Edd}$. The steady UV emission and strong X-ray absorption variability suggest that the obscuring clouds are likely compact and affect the compact X-ray source only and do not possibly cover the extended UV emitting region. In addition, the UVIT is able to resolve two bright spots at a radius of 7" ($\sim$ 6.3 Kpc) from the central nucleus in the South-West (SW) direction. In the UVIT image of the entire galaxy, we identify UV counterparts to four Chandra identified bright X-ray sources. One well-known ultra-luminous X-ray source (ULX) NGC 1365 X2 is identified with its UV counterpart at 86" from the nucleus in the north-east (NE) direction from the active nucleus.

We present the first detailed investigation of six eclipsing binary systems in the TESS field. The TESS light curves of the targets are analysed by determining the initial effective temperatures via SED fits. The absolute parameters are derived and the systems are compared to well-known binaries of the same type. Results show that CD-58~791, CD-62~1257 and TYC~9356-355-1 are detached binary systems. CD-54~942 and UCAC4~136-007295 are contact binaries while TYC~8508-1413-1 is a semidetached system.

A new water-Cherenkov radiation detector, located at the Argentine Marambio Antarctic Base (64.24S-56.62W), has been monitoring the variability of galactic cosmic ray (GCR) flux since 2019. One of the main aims is to provide experimental data necessary to study interplanetary transport of GCRs during transient events at different space/time scales. In this paper we present the detector and analyze observations made during one full year. After the analysis and correction of the GCR flux variability due to the atmospheric conditions (pressure and temperature), a study of the periodicities is performed in order to analyze modulations due to heliospheric phenomena. We can observe two periods: (a) 1 day, associated with the Earth's rotation combined with the spatial anisotropy of the GCR flux; and (b) $\sim$ 30 days due to solar impact of stable solar structures combined with the rotation of the Sun. From a superposed epoch analysis, and considering the geomagnetic effects, the mean diurnal amplitude is $\sim$ 0.08% and the maximum flux is observed in $\sim$ 15 hr local time (LT) direction in the interplanetary space. In such a way, we determine the capability of Neurus to observe anisotropies and other interplanetary modulations on the GCR flux arriving at the Earth.

In the last few years the concept of an active space telescope has been greatly developed, to meet demanding requirements with a substantial reduction of tolerances, risks and costs. This is the frame of the LATT project (an ESA TRP) and its follow-up SPLATT (an INAF funded R&D project). Within the SPLATT activities, we outline a novel approach and investigate, both via simulations and in the optical laboratory, two main elements: an active segmented primary with contactless actuators and a pyramid wavefront sensor (PWFS) to drive the correction chain. The key point is the synergy between them: the sensitivity of the PWFS and the intrinsic stability of a contactless-actuated mirror segment. Voice-coil, contactless actuators are in facts a natural decoupling layer between the payload and the optical surface and can suppress the high frequency vibration as we verified in the lab. We subjected a 40 cm diameter prototype with 19 actuators to an externally injected vibration spectrum; we then measured optically the reduction of vibrations when the optical surface is floating controlled by the actuators, thus validating the concept at the first stage of the design. The PWFS, which is largely adopted on ground-based telescope, is a pupil-conjugated sensor and offers a user-selectable sampling and capture range, in order to match different use cases; it is also more sensitive than Shack-Hartmann sensor especially at the low-mid spatial scales. We run a set of numerical simulations with the PWFS measuring the misalignment and phase steps of a JWST-like primary mirrors: we investigated the PWFS sensitivity in the sub-nanometer regime in presence of photon and detector noise, and with guide star magnitudes in the range 8 to 14. In the paper we discuss the outcomes of the project and present a possible roadmap for further developments.

X-ray polarimetry, based on Gas Pixel Detectors (GPDs), have reached a high level of maturity with the Imaging X-ray Polarimeter Explorer (IXPE) leading to the first ever spatially resolved polarimetric measures. However, being this a new technique, a few unexpected effect have emerged during in flight operations. In particular it was almost immediately found that on-board unpolarized calibration sources were showing radially polarized halos. The origin of this features was recognized in a correlation between the error in reconstructing the absorption point of the X-ray photon and the direction of its electric field vector. Here we present and discuss in detail this effect, showing that it is possible to provide a simple and robust mathematical formalism to handle it. We further show its role and relevance for the recent IXPE measures, and for the use of GPD-based techniques in general, and illustrate how to model it in the study of extended sources.

We present results from the Met Office Unified Model (UM), a world-leading climate and weather model, adapted to simulate a dry Martian climate. We detail the adaptation of the basic parameterisations and analyse results from two simulations, one with radiatively active mineral dust and one with radiatively inactive dust. These simulations demonstrate how the radiative effects of dust act to accelerate the winds and create a mid-altitude isothermal layer during the dusty season. We validate our model through comparison with an established Mars model, the Laboratoire de M\'et\'eorologie Dynamique planetary climate model (PCM), finding good agreement in the seasonal wind and temperature profiles but with discrepancies in the predicted dust mass mixing ratio and conditions at the poles. This study validates the use of the UM for a Martian atmosphere, highlighting how the adaptation of an Earth general circulation model (GCM) can be beneficial for existing Mars GCMs and provides insight into the next steps in our development of a new Mars climate model.

Citizen science is gaining popularity as a valuable tool for labelling large collections of astronomical images by the general public. This is often achieved at the cost of poorer quality classifications made by amateur participants, which are usually verified by employing smaller data sets labelled by professional astronomers. Despite its success, citizen science alone will not be able to handle the classification of current and upcoming surveys. To alleviate this issue, citizen science projects have been coupled with machine learning techniques in pursuit of a more robust automated classification. However, existing approaches have neglected the fact that, apart from the data labelled by amateurs, (limited) expert knowledge of the problem is also available along with vast amounts of unlabelled data that have not yet been exploited within a unified learning framework. This paper presents an innovative learning paradigm for citizen science capable of taking advantage of expert- and amateur-labelled data, and unlabelled data. The proposed methodology first learns from unlabelled data with a convolutional autoencoder and then exploits amateur and expert labels via the pre-training and fine-tuning of a convolutional neural network, respectively. We focus on the classification of galaxy images from the Galaxy Zoo project, from which we test binary, multi-class, and imbalanced classification scenarios. The results demonstrate that our solution is able to improve classification performance compared to a set of baseline approaches, deploying a promising methodology for learning from different confidence levels in data labelling.

We developed game-changing concepts for meter(s) class very-wide-field telescopes, spanning three orders of magnitude of the covered field of view. Multiple cameras and monocentric systems: from the Smart Fast Cameras (with a quasi-monocentric aperture), through the FlyEye, toward a MezzoCielo concept (both with a truly monocentric aperture). MezzoCielo (or "half of the sky") is the last developed concept for a new class of telescopes. Such a concept is based on a fully spherical optical surface filled with a low refractive index, and high transparency liquid surrounded by multiple identical cameras. MezzoCielo is capable to reach field of views in the range of ten to twenty thousand square degrees.

Up to date, only 6 imines have been detected in the interstellar medium. The 3-carbon imine, 2-propanimine ((CH$_3$)$_2$C=NH), is predicted to be the structural isomer with the lowest energy in the C$_3$H$_7$N group, and appears to be a good candidate for astronomical searches. Unexpectedly, no microwave or millimeter wave spectrum is available for 2-propanimine. In this work, we provide the first high resolution millimeter wave spectrum of 2-propanimine and its analysis. With the guide of this laboratory measurement, we aim to search for 2-propanimine in two molecule-rich sources Sgr B2(N) and IRAS 16293-2422 using observations from the Atacama Large Millimeter/submillimeter Array (ALMA). Starting from a synthesized sample, we measured the spectrum of 2-propanimine from 50 to 500 GHz, and the ground state lines are successfully assigned and fitted using XIAM and ERHAM programs with the aid of theoretical calculations. The barriers to internal rotation of the two CH$_3$ tops are determined to be 531.956(64) cm$^{-1}$ and 465.013(26) cm$^{-1}$. These data are able to provide reliable prediction of transition frequencies for astronomical search. Although a few line matches exist, no confirmed detection of 2-propanimine has been found in the hot molecular core Sgr B2(N1S) and the Class 0 protostar IRAS 16293B. Upper-limits of its column density have been derived, and indicate that 2-propanimine is at least 18 times less abundant than methanimine in Sgr B2(N1S), and is at most 50-83 % of methanimine in IRAS 16293B.

Coupled models of quintessence are usually introduced for avoiding or mitigating the parameter fine-tuning problem. At the same time, the coupled models should avoid the fine-tuning problem related to the initial conditions as quintessence models do. One more attractive feature of coupled models might be the explanation of the timescale at which the coincidence of DE and matter energy densities occur and the understanding of reason why after this the DE takes over. And finally, all these nice features should be unaffected by the quantum corrections of the potential. Having in mind these remarks, we shall focus our discussion on mass varying neutrino model of DE with inverse power-law potential to see how naturally does it work.

The Survey for Distant Solar Twins (SDST) aims to find stars very similar to the Sun at distances 1-4 kpc, several times more distant than any currently known solar twins and analogues. The goal is to identify the best stars with which to test whether the fine-structure constant, alpha, varies with dark matter density in our Galaxy. Here we use EPIC, our line-by-line differential technique, to measure the stellar parameters - effective temperature Teff, surface gravity log g, metallicity [Fe/H] - from moderate resolution (R < 32,000) spectra of 877 solar twin and analogue candidates (547 at 1-4 kpc) observed with the HERMES spectrograph on the Anglo-Australian Telescope. These are consistent with expectations for Teff and log g from photometry, and for [Fe/H] from the Besancon stellar population model. EPIC provides small enough uncertainties (~90 K, 0.08 dex, 0.05 dex, respectively), even at the low signal-to-noise ratios available (S/N >~ 25 per pixel), to identify 299 new solar analogues (> 90% confidence), and 20 solar twins (>50% confidence), 206 and 12 of which are at 1-4 kpc. By extending EPIC to measure line broadening and lithium abundance from HERMES spectra, and with ages derived from isochrone fitting with our stellar parameters, we identify 174 solar analogues at 1-4 kpc which are relatively inactive, slowly rotating, and with no evidence of spectroscopic binarity. These are the preferred targets for follow-up spectroscopy to measure alpha.

We determined the full orbital architecture and true mass of the recently Doppler-detected long-period giant planet GJ 463 b using the HIPPARCOS-Gaia proper motion anomaly in combination with the available radial velocities, constraints from the knowledge of the spectroscopic orbital parameters, and supplementary information from a sensitivity analysis of Gaia Data Release 3 astrometry. We determined an orbital inclination $i_b=152^{+2}_{-3}$ deg (for a prograde orbit) and a mass ratio $q=0.0070\pm0.0007$, corresponding to a true mass of the companion $M_b=3.6\pm0.4$ M$_\mathrm{Jup}$. True mass determinations for a super-Jupiter companion at intermediate orbital separations beyond the snow line around low-mass stars ($M_\star\leq 0.5$ M$_\odot$) are a rare occurrence. Its existence is possibly explained in the context of disk-instability models of planet formation.

The class of transiting cold Jupiters, orbiting at $\gtrsim0.5-1.0$ au, is to-date underpopulated. Probing their atmospheric composition and physical characteristics is particularly valuable, as it allows for direct comparisons with the Solar System giant planets. We investigate some aspects of the synergy between Gaia astrometry and other ground-based and space-borne programs for detection and characterization of such companions. We carry out numerical simulations of Gaia observations of systems with one cold transiting gas giant, using Jovian planets around a sample of nearby low-mass stars as proxies. Using state-of-the-art orbit fitting tools, we gauge the potential of Gaia astrometry to predict the time of transit centre $T_c$ for the purpose of follow-up observations to verify that the companions are indeed transiting. Typical uncertainties on $T_c$ will be on the order of a few months, reduced to several weeks for high astrometric signal-to-noise ratios and periods shorter than $\sim3$ yr. We develop a framework for the combined analysis of Gaia astrometry and radial-velocity data from representative ground-based campaigns and show that combined orbital fits would allow to significantly reduce the transit windows to be searched for, down to about $\pm2$ weeks ($2-\sigma$ level) in the most favourable cases. These results are achievable with a moderate investment of observing time ($\sim0.5$ nights per candidate, $\sim50$ nights for the top 100 candidates), reinforcing the notion that Gaia astrometric detections of potentially transiting cold giant planets, starting with Data Release 4, will constitute a valuable sample worthy of synergistic follow-up efforts with a variety of techniques.

We present a Zeeman-Doppler imaging study of two weak-line T Tauri stars TAP 4 and TAP 40, based on the high-resolution spectropolarimetric observations with ESPaDOnS at the Canada-France-Hawaii Telescope in November 2013, in the framework of the MaTYSSE large programme. We apply two Zeeman-Doppler imaging codes to the Stokes I and V profiles to reconstruct their brightness and large-scale magnetic field images. The results given by the two imaging codes are in good agreement with each other. TAP 4 shows a large polar cool spot and several intermediate-latitude warm spots on its surface, whereas TAP 40 exhibits very weak variations in its Stokes I profiles suggesting a mostly unspotted photosphere. We detect Zeeman signatures in the Stokes V profiles of both stars. The reconstructed magnetic maps reveal dominantly toroidal fields, which enclose about 60 per cent of the total magnetic energy for both of TAP 4 and TAP 40. Both stars show prominent circular ring features of the azimuthal magnetic field. We derive a solar-like surface differential rotation on TAP 4 from the tomographic modelling. The brightness image of TAP 4 is used to predict the radial velocity jitters induced by its activity. After filtering out the activity jitter, the RMS of its RVs is reduced from 1.7 km s$^{-1}$ to 0.2 km s$^{-1}$, but we do not detect any periodic signals in the filtered RVs of TAP 4, implying that it is unlikely to host a close-in exoplanet more massive than $\sim$3.5 M$_{\rm Jup}$ at 0.1 au.

The latest high-performance telescopes for deep space observation employ very large primary mirrors that are made of smaller segments, like the JWST which employs monolithic beryllium hexagonal segments. A very promising development stage of these systems is to make them active and to operate on their reflective surfaces to change their shape and compensate for aberrations as well as to perform a very precise alignment. This is possible by employing a reference body that stores actuators to modify the shape of the shell, like in the SPLATT project where voice coil actuators are used. However, the lack of physical contact between the main body and shell places, along with the many advantages related to the physical decoupling of the two bodies, some concerns related to the retaining of the shell under all the possible acceleration conditions affecting the system during the mission lifetime. This paper aims to study the acceleration environment affecting the spacecraft during its lifetime and to use it as a baseline for operational requirements of a retaining system for the shells. Any solution is selected in this paper to leave complete freedom for the development of a constraining system, just some are qualitatively discussed.

We present a molecular line study of the Sh2-138 (IRAS 22308+5812) hub-filament system with an aim to investigate its structure and kinematics. Archival CO molecular line data from the Canadian Galactic Plane Survey (CO(J=1-0)) for the wider region (50arcminx50arcmin) and the James Clerk Maxwell Telescope (CO(3-2), 13CO(3-2), and C18O(3-2)) for the central portion (5arcminx5arcmin) have been utilised. Analysis of the CO(1-0) spectra for the extended region in conjunction with the hub and filament identification using column density map and the getsf tool, respectively, reveals a complex structure with the spectral extraction for the central position displaying multiple velocity components. Based on the Herschel 70 micron warm dust emission, one of the filaments in the extended region was inferred to be associated with active star formation, and is host to a Bolocam 1.1 mm clump of 1606 Msun. Integrated intensity map of 13CO(3-2) emission, constructed from clumps detected at above 5sigma in position-position-velocity space, reveals three filamentary structures (labelled W-f, SW-f, and SE-f) in the central portion. Velocity gradients observed in 13CO(3-2) position-velocity slices point to longitudinal gas flow along the filaments into the central region. Filaments W-f, SW-f, and SE-f were calculated to have observed line masses of 32, 33.5, and 50 Msun/pc , respectively. The cloud was found to be dominated by supersonic and non-thermal motions, with high Mach numbers (>3) and low thermal to non-thermal pressure ratio (0.01-0.1).

We present new HCN and HCO$^+$ ($J$=3-2) images of the nearby star-forming galaxies (SFGs) NGC 3351, NGC 3627, and NGC 4321. The observations, obtained with the Morita ALMA Compact Array, have a spatial resolution of $\sim$290-440 pc and resolve the inner $R_\textrm{gal} \lesssim$ 0.6-1 kpc of the targets, as well as the southern bar end of NGC 3627. We complement this data set with publicly available images of lower excitation lines of HCN, HCO$^+$, and CO and analyse the behaviour of a representative set of line ratios: HCN(3-2)/HCN(1-0), HCN(3-2)/HCO$^+$(3-2), HCN(1-0)/CO(2-1), and HCN(3-2)/CO(2-1). Most of these ratios peak at the galaxy centres and decrease outwards. We compare the HCN and HCO$^+$ observations with a grid of one-phase, non-local thermodynamic equilibrium (non-LTE) radiative transfer models and find them compatible with models that predict subthermally excited and optically thick lines. We study the systematic variations of the line ratios across the targets as a function of the stellar surface density ($\Sigma_\textrm{star}$), the intensity-weighted CO(2-1) ($\langle I_\text{CO}\rangle$), and the star formation rate surface density ($\Sigma_\text{SFR}$). We find no apparent correlation with $\Sigma_\text{SFR}$, but positive correlations with the other two parameters, which are stronger in the case of $\langle I_\text{CO}\rangle$. The HCN/CO-$\langle I_\text{CO}\rangle$ relations show $\lesssim$0.3 dex galaxy-to-galaxy offsets, with HCN(3-2)/CO(2-1)-$\langle I_\text{CO}\rangle$ being $\sim$2 times steeper than HCN(1-0)/CO(2-1). In contrast, the HCN(3-2)/HCN(1-0)-$\langle I_\text{CO}\rangle$ relation exhibits a tighter alignment between galaxies. We conclude that the overall behaviour of the line ratios cannot be ascribed to variations in a single excitation parameter (e.g. density or temperature).

The modulation of the intensity of microwave emission from a plasma slab caused by a standing linear kink fast magnetoacoustic wave is considered. The slab is stretched along a straight magnetic field, and can represent, for example, a current sheet in a flaring active region in corona of the Sun, or a streamer or pseudostreamer stalk. The plasma density is non-uniform in the perpendicular direction and described by a symmetric Epstein profile. The plasma parameter $\beta$ is taken to be zero, which is a good approximation for solar coronal active regions. The microwave emission is caused by mildly relativistic electrons which occupy a layer within the oscillating slab and radiate via the gyrosynchrotron (GS) mechanism. Light curves of the microwave emission were simulated in the optically thin part of the GS spectrum, and their typical Fourier spectra were analysed. It is shown that the microwave response to a linear kink magnetohydrodynamic wave is non-linear. It is found that, while the microwave light curves at the node oscillate with the same frequency as the frequency of the perturbing kink mode, the frequency of the microwave oscillations at the anti-node is two times higher than the kink oscillation frequency. Gradual transformation the one type of the light curves to another occurs when sliding from the node to the anti-node. This result does not depend on the width of the GS-emitting layer inside the oscillating slab. This finding should be considered in the interpretation of microwave quasi-periodic pulsations in solar and stellar flares.

It has been suggested that tidal interaction is important for shaping the orbital configurations of close orbiting giant planets. The excitation of propagating waves and normal modes (dynamical tide) will be important for estimating time scales for orbital evolution. We consider the tidal interaction of a Jupiter mass planet orbiting a solar type primary. Tidal and rotational frequencies are assumed comparable making the effect of rotation important. Although centrifugal distortion is neglected, Coriolis forces are fully taken into account. We focus in detail on the potentially resonant excitation of $r$ modes associated with spherical harmonics of degrees three and five. These are mostly sited in the radiative core but with a significant response in the convective envelope where dissipation occurs. Away from resonance significant orbital evolution over the system lifetime is unlikely. However, tidal interaction is enhanced near resonances and the orbital evolution accelerated as they are passed through. This speed up may be sustained if near resonance can be maintained. For close orbits with primaries rotating sufficiently rapidly, this could arise from angular momentum loss and stellar spin down through a stellar wind bringing about significant orbital evolution over the system lifetime.

While the direct detection of the dark-matter particle remains very challenging, the nature of dark matter could be possibly constrained by comparing the observed abundance and properties of small-scale sub-galactic mass structures with predictions from the phenomenological dark-matter models, such as cold, warm or hot dark matter. Galaxy-galaxy strong gravitational lensing provides a unique opportunity to search for tiny surface-brightness anomalies in the extended lensed images (i.e. Einstein rings or gravitational arcs), induced by possible small-scale mass structures in the foreground lens galaxy. In this paper, the first in a series, we introduce and test a methodology to measure the power spectrum of such surface-brightness anomalies from high-resolution Hubble Space Telescope (HST) imaging. In particular, we focus on the observational aspects of this statistical approach, such as the most suitable observational strategy and sample selection, the choice of modelling techniques and the noise correction. We test the feasibility of the power-spectrum measurement by applying it to a sample of galaxy-galaxy strong gravitational lens systems from the Sloan Lens ACS Survey, with the most extended, bright, high-signal-to-noise-ratio lensed images, observed in the rest frame ultraviolet. In the companion paper, we present the methodology to relate the measured power spectrum to the statistical properties of the underlying small-scale mass structures in the lens galaxy and infer the first observational constraints on the sub-galactic matter power spectrum in a massive elliptical (lens) galaxy.

The Spectrometer/Telescope for Imaging X-rays (STIX) onboard Solar Orbiter observes solar X-ray emission in the range of 4 to 150 keV and produces spectra and images of solar flares over a wide range of flare magnitudes. During nominal operation, STIX continuously generates data. A constant data flow requires fully automated data processing pipelines to process and analyze and a data platform to manage, visualize, and distribute the data products to the scientific community. The STIX Data Center has been built to fulfill these needs. In this paper, we outline its main components to help the community better understand the tools and data it provides. Methods. The STIX Data Center is operated at the University of Applied Sciences and Arts Northwestern Switzerland (FHNW) and consists of automated processing pipelines and a data platform. The pipelines process STIX telemetry data, perform common analysis tasks and generate data products at different processing levels. They have been designed to operate fully automatically with minimal human intervention. The data platform provides web-based user interfaces and application programmable interfaces for searching and downloading STIX data products. The STIX Data Center has been operating successfully for more than two years. The platform facilitates instrument operations and provides vital support to STIX data users.

We explore the properties of the host galaxies of X-ray selected AGN in the COSMOS field using the Chandra Legacy sample and the LEGA-C survey VLT optical spectra. Our main goal is to compare the relative ages of the host galaxies of the obscured and unobscured AGN by means of the calcium break Dn(4000) and the Hdelta Balmer line. The host galaxy ages are examined in conjunction with other properties such as the galaxy stellar mass, and star-formation rate as well as the AGN Eddington ratio. Our sample consists of 50 unobscured or mildly obscured (logN_H (cm-2) < 23) and 23 heavily obscured AGN (log N_H (cm-2) >23) in the redshift range z=0.6-1. We take specific caution to create control samples in order to match the exact luminosity and redshift distributions for the obscured and unobscured AGN. The majority of unobscured AGN appear to live in young galaxies in contrast to the obscured AGN which appear to live in galaxies located between the young and old galaxy populations. This finding may be in contrast to those evolutionary AGN unification models which postulate that the AGN begin their life in a heavy obscuration phase. The host galaxies of the obscured AGN have significantly lower levels of specific star-formation. At the same time the obscured AGN have lower Eddington ratios indicating a link between the star-formation and the black hole accretion. We find that the distribution of the stellar masses of the host galaxies of obscured AGN is skewed towards higher stellar masses in agreement with previous findings. Our results on the relative age of obscured AGN are valid when we match our obscured and unobscured AGN samples according to the stellar mass of their host galaxies. All the above results become less conspicuous when a lower column density (log N_H(cm-2)= 21.5 or 22) is used to separate the obscured and unobscured AGN populations.

(Shortened version) Current efforts in space weather forecasting of CMEs have been focused on predicting their arrival time and magnetic structure. To make predictions, methods have been developed to derive the true CME speed, size and position, among others. Difficulties in determining input parameters for CME forecasting arise from the lack of direct measurements of the coronal magnetic fields and uncertainties in estimating the CME 3D geometric and kinematic parameters. White-light coronagraph images are usually employed by a variety of CME reconstruction techniques. We explore how subjectivity affects the 3D CME parameters that are obtained from the GCS reconstruction technique. We have designed two different synthetic scenarios where the ``true'' geometric parameters are known in order to quantify such uncertainties for the first time. We explore this as follows: 1) Using the ray-tracing option from the GCS model software, and 2) Using 3D MHD simulation data from the MAS code. Our experiment includes different viewing configurations using single and multiple viewpoints. CME reconstructions using a single viewpoint had the largest errors and error ranges for both synthetic GCS and simulated MHD white-light data. Increasing the number of viewpoints to two, the errors decreased by about 4$^\circ$ in latitude, 22$^\circ$ in longitude, 14$^\circ$ in tilt, and 10$^\circ$ in half-angle, pointing towards a need for at least two viewpoints. We found the following CME parameter error bars as a starting point for quantifying the minimum error in CME parameters from white-light reconstructions: $\Delta\theta$ (latitude)=${6^\circ}$, $\Delta\phi$ (longitude)=${11^\circ}$, $\Delta\gamma$ (tilt)=${25^\circ}$, $\Delta\alpha$ (half-angle)=${10^\circ}$, $\Delta h$ (height)=$0.6$\,$R_{\odot}$, and $\Delta\kappa$ (ratio)=$0.1$.

Equations governing the evolution of a star involve multiple coupling constants. Thus, the time it spends as a main-sequence star can be expected to depend on whether or not such constants vary over the time scale of stellar evolution. When the star belongs to a globular cluster, the star's age cannot exceed that of the globular cluster, and the latter cannot exceed the age of the Universe. This fact can be used to constrain or verify the variation of the coupling constants, i.e., the speed of light c, the gravitational constant G, the Planck constant h, and the Boltzmann constant k. We have estimated the age of the main-sequence star analytically from the time it takes to synthesize all its hydrogen into helium under fixed and varying coupling constants scenarios. When we permitted the interrelated variation of the four constants ($G\thicksim c^{3}\thicksim h^{3}\thicksim k^{3/2}$) and differentiated between the cosmological energy and local energy conservation laws, we could show that the variation of the constants established in our earlier studies, i.e., $(\dot{G}/G)_{0}=3(\dot{c}/c)_{0}=(\dot{h}/h)_{0}=1.5 (\dot{k}/k)_{0}=5.4H_{0} =3.90(\pm 0.04)\times 10^{-10} yr^{-1}$ at the current cosmic time is consistent with the present work. Nevertheless, the challenge remains to come up with an experiment, astrometric or terrestrial, that can unequivocally prove or falsify the predicted variation.

To better understand the orbital dynamics of exoplanets around close binary stars, i.e., circumbinary planets (CBPs), we applied techniques from dynamical systems theory to a physically motivated set of solutions in the Circular Restricted Three-Body Problem (CR3BP). We applied Floquet theory to characterize the linear dynamical behavior -- static, oscillatory, or exponential -- surrounding planar circumbinary periodic trajectories (limit cycles). We computed prograde and retrograde limit cycles and analyzed their geometries, stability bifurcations, and dynamical structures. Orbit and stability calculations are exact computations in the CR3BP and reproducible through the open-source Python package pyraa. The periodic trajectories produce a set of non-crossing, dynamically cool circumbinary orbits conducive to planetesimal growth. For mass ratios $\mu \in [0.01, 0.50]$ we found recurring features in the prograde families. These features include: (1) an innermost near-circular trajectory, inside which solutions have resonant geometries, (2) an innermost stable trajectory ($a_{cr} \approx 1.61 - 1.85 \, a_\textrm{bin}$) characterized by a tangent bifurcating limit cycle, and (3) a region of dynamical instability ($a \approx 2.1 \ a_\textrm{bin}; \Delta a \approx 0.1 \ a_\textrm{bin}$), the exclusion zone, bounded by a pair of critically stable trajectories -- bifurcating limit cycles. The exterior boundary of the exclusion zone is consistent with prior determinations of $a_{cr}$ around a circular binary. We validate our analytic results with N-body simulations and apply them to the Pluto-Charon system. The absence of detected CBPs in the inner stable region, between the prograde exclusion zone and $a_{cr}$, suggests that the exclusion zone may inhibit the inward migration of CBPs.

Highly energetic stellar tidal disruption events (TDEs) provide a way to study black hole characteristics and their environment. We simulate TDEs with the PHANTOM code in a general relativistic and Newtonian description of a supermassive black hole's gravity. Stars, which are placed on parabolic orbits with different parameters $\beta$, are constructed with the stellar evolution code MESA and therefore have realistic stellar density profiles. We study the mass fallback rate of the debris $\dot{M}$ and its dependence on the $\beta$, stellar mass and age as well as the black hole's spin and the choice of the gravity's description. We calculate peak value $\dot{M}_\mathrm{peak}$, time to the peak $t_\mathrm{peak}$, duration of the super-Eddington phase $t_\mathrm{Edd}$, time $t_{>0.5\dot{M}_\mathrm{peak}}$ during which $\dot{M}>0.5\dot{M}_\mathrm{peak}$, early rise-time $\tau_\mathrm{rise}$ and late-time slope $n_\infty$. We recover the trends of $\dot{M}_\mathrm{peak}$, $t_\mathrm{peak}$, $\tau_\mathrm{rise}$ and $n_\infty$ with $\beta$, stellar mass and age, which were obtained in previous studies. We find that $t_\mathrm{Edd}$, at a fixed $\beta$, scales primarily with the stellar mass, while $t_{>0.5\dot{M}_\mathrm{peak}}$ scales with the compactness of stars. The effect of SMBH's rotation depends on the orientation of its rotational axis relative to the direction of the stellar motion on the initial orbit. Encounters on prograde orbits result in narrower $\dot{M}$ curves with higher $\dot{M}_\mathrm{peak}$, while the opposite occurs for retrograde orbits. We find that disruptions, at the same pericenter distance, are stronger in a relativistic tidal field than in a Newtonian. Therefore, relativistic $\dot{M}$ curves have higher $\dot{M}_\mathrm{peak}$, and shorter $t_\mathrm{peak}$ and $t_\mathrm{Edd}$.

The formation and subsequent migration of gas giants could significantly affect the material mixing in the Solar System. In this study, we use N-body simulations to investigate how much water is transported into the region of the terrestrial planet formation during the growth and migration phases of Jupiter in the Grand Tack model. We found that Jupiter's growth was accompanied by significant mass transport, and that a substantial amount of water (about 10 times Earth's ocean mass for the initial planetesimal distribution based on the minimum-mass solar nebula) was transported into the terrestrial planet region. The total amount delivered increased further during Jupiter's migration phase (totaling about 10-40 times Earth's ocean mass), which was less dependent on simulation parameters. In addition, at these stages, terrestrial planets were not fully grown. Therefore, water supplied during these early stages could interact with metallic iron during the core formation of protoplanets and/or growing Earth. Since hydrogen in water molecules can dissolve into their cores, this could explain the density deficit observed in the current Earth core. Notably, Jupiter could play an important role as a ''barrier'' in explaining the dichotomy of the isotopic compositions between noncarbonaceous (NC) and carbonaceous (CC) meteorites. This study's results show that Jupiter's growth necessitates some mixing of NC and CC materials.

In this work, we present UV completions of the recently proposed number-changing Co-SIMP freeze-out mechanism. In contrast to the standard cannibalistic-type dark matter picture that occurs entirely in the dark sector, the $3\to 2$ process setting the relic abundance in this case requires one Standard Model particle in the initial and final states. This prevents the dark sector from overheating and leads to rich experimental signatures. We generate the Co-SIMP interaction with a dark sector consisting of two scalars, with the mediator coupling to either nucleons or electrons. In either case, \textit{the dark matter candidate is naturally light}: nucleophilic interactions favor the sub-GeV mass range and leptophilic interactions favor the sub-MeV mass range. Viable thermal models in these lighter mass regimes are particularly intriguing to study at this time, as new developments in low-threshold detector technologies will begin probing this region of parameter space. While particles in the sub-MeV regime can potentially impact light element formation and CMB decoupling, we show that a late-time phase transition opens up large fractions of parameter space. These thermal light dark matter models can instead be tested with dedicated experiments. We discuss the viable parameter space in each scenario in light of the current sensitivity of various experimental probes and projected future reach.

We advocate an idea that ``non-baryonic" dark matter in form of nuggets made of standard model quarks and gluons (similar to the old idea of the Witten's strangelets) could play a crucial role in structure formation. The corresponding macroscopically large objects, which are called the axion quark nuggets (AQN) behave as {\it chameleons}: they do not interact with the surrounding material in dilute environment, but they become strongly interacting objects in sufficiently dense environment. The AQN model was invented long ago with a single motivation to explain the observed similarity $\Omega_{\rm DM}\sim \Omega_{\rm visible}$ between visible and DM components. This relation represents a very generic feature of this framework, not sensitive to any parameters of the construction. We argue that the strong visible-DM interaction may dramatically modify the conventional structure formation pattern at small scales to contribute to a resolution of a variety of interconnected problems (such as Core-Cusp problem, etc) which have been a matter of active research and debates in recent years. We also argue that the same visible-DM interaction at small scales is always accompanied by a broad band diffuse radiation. We speculate that the recently observed excesses of the UV emission by JWST at high redshifts and by GALEX in our own galaxy might be a direct manifestation of this AQN-induced radiation. We also speculate that the very same source of energy injection could contribute to the resolution of another long standing problem related to the Extragalactic Background Light (EBL) with known discrepancies in many frequency bands (from UV to optical, IR light and radio emissions).

Within Einstein's General Relativity we study exotic stars made of dark energy assuming an extended Chaplygin gas equation-of-state. Taking into account the presence of anisotropies, we employ the formalism based on the complexity factor to solve the structure equations numerically, obtaining thus interior solutions describing hydrostatic equilibrium. Making use of well-established criteria we demonstrate that the solutions are well behaved and realistic. A comparison with another, more conventional approach, is made as well.

Accurate and extensive atomic data are essential for spectroscopic analyses of stellar atmospheres and other astronomical objects. We present energy levels, lifetimes, and transition probabilities for neutral nitrogen, the sixth most abundant element in the cosmos. The calculations employ the fully relativistic multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction methods, and span the 103 lowest states up to and including 2s$^2$2p$^2$5s. Our theoretical energies are in excellent agreement with the experimental data, with an average relative difference of 0.07%. In addition, our transition probabilities are in good agreement with available experimental and theoretical data. We further verify the agreement of our data with experimental results via a re-analysis of the solar nitrogen abundance, with the results from the Babushkin and Coulomb gauges consistent to 2% or 0.01 dex. We estimated the uncertainties of the computed transition data based on a statistical analysis of the differences between the transition rates in Babushkin and Coulomb gauges. Out of the 1701 computed electric dipole transitions in this work, 83 (536) are associated with uncertainties less than 5% (10%).

Gravitational waves offer a new window to probe the nature of gravity, including answering if the mediating particle, graviton, has a non-zero mass or not. Pulsar timing arrays measure stochastic gravitational wave background (SGWB) at $\sim1-100$~nanohertz. Recently, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration reported an uncorrelated common-spectrum process in their 12.5-year data set with no substantial evidence that the process comes from the SGWB predicted by general relativity. In this work, we explore the possibility of an SGWB from massive gravity in the data set and find that a massless graviton is preferred because of the relatively larger Bayes factor. Without statistically significant evidence for dispersion-related correlations predicted by massive gravity, we place upper limits on the amplitude of the SGWB for graviton mass smaller than $10^{-23}$~eV as $A_{\rm{MG}}<3.21\times 10^{-15}$ at $95\%$ confidence level.

The computational cost of searching for gravitational wave (GW) signals in low latency has always been a matter of concern. We present a self-supervised learning model applicable to the GW detection. Based on simulated massive black hole binary signals in synthetic Gaussian noise representative of space-based GW detectors Taiji and LISA sensitivity, and regarding their corresponding datasets as a GW twins in the contrastive learning method, we show that the self-supervised learning may be a highly computationally efficient method for GW signal identification.

The characteristics of a hydrogenated amorphous silicon (a-Si:H) detector are presented here for monitoring in space solar flares and the evolution of large energetic proton events up to hundreds of MeV. The a-Si:H presents an excellent radiation hardness and finds application in harsh radiation environments for medical purposes, for particle beam characterization and in space weather science and applications. The critical flux detection threshold for solar X rays, soft gamma rays, electrons and protons is discussed in detail.

We outline a new explanation for the primordial density perturbations in cosmology. Dimension zero fields are a minimal addition to the Standard Model of particle physics: if the Higgs doublet is emergent, they cancel the vacuum energy and both Weyl anomalies without introducing any new particles. Furthermore, the cancellation explains why there are three generations of elementary particles, including RH neutrinos. We show how quantum zero point fluctuations of dimension zero fields seed nearly scale-invariant, Gaussian, adiabatic density perturbations. We calculate the amplitude of the primordial perturbations in terms of Standard Model couplings and find a result consistent with large scale observations. Subject to two key theoretical assumptions, both the amplitude and the tilt we calculate agree with the observed values, with no free parameters.

The relativistic effects in cosmological observables contain critical information about the initial conditions and gravity on large scales. Compared to the matter density fluctuation, some of these relativistic contributions scale with negative powers of comoving wave number, implying a growing sensitivity to infrared modes. However, this can be inconsistent with the equivalence principle and can also lead to infrared divergences in the observable $N$-point statistics. Recent perturbative calculations have shown that this infrared sensitivity is indeed spurious due to subtle cancellations in the cosmological observables that have been missed in the bulk of the literature. Here we demonstrate that the cosmological observable statistics are infrared-insensitive in a general and fully non-linear way, assuming diffeomorphism invariance and adiabatic fluctuations on large scales.

In relativistic plasmas of sufficiently high temperature, fermion chirality can be interchanged with magnetic helicity while preserving the total chirality through the quantum chiral anomaly. Here we show, using a high resolution numerical simulation, that in the case of zero total chirality, where the magnetic helicity density balances with the appropriately scaled chiral chemical potential to zero, the magnetic energy density decays and the correlation length increases with time just like in nonhelical turbulence with vanishing chiral chemical potential. But here, the magnetic helicity density is nearly maximum and shows a novel scaling with time $t$ proportional to $t^{-2/3}$. This is unrelated to the $t^{-2/3}$ decay of magnetic {\it energy} in fully helical magnetic turbulence. The modulus of the chiral chemical potential decays in the same fashion. These decay laws can be determined from the conservation of what is known as the Hosking integral, adapted here to include the effect of the chiral chemical potential. We compute the adapted Hosking integral and confirm that it is indeed approximately conserved.

Correlation functions of primordial density fluctuations provide an exciting probe of the physics governing the earliest moments of our Universe. However, the standard approach to compute them is technically challenging. Theoretical predictions are therefore available only in restricted classes of theories. In this Letter, we present a complete method to systematically compute tree-level inflationary correlators. This method is based on following the time evolution of equal-time correlators and it accurately captures all physical effects in any theory. These theories are conveniently formulated at the level of inflationary fluctuations, and can feature any number of degrees of freedom with arbitrary dispersion relations and masses, coupled through any type of time-dependent interactions. We demonstrate the power of this approach by exploring the properties of the cosmological collider signal, a discovery channel for new high-energy physics, in theories with strong mixing and in the presence of features. This work lays the foundation for a universal program to assist our theoretical understanding of inflationary physics and generate theoretical data for an unbiased interpretation of upcoming cosmological observations.

Current templated searches for gravitational waves (GWs) emanated from compact binary coalescences (CBCs) assume that the binaries have circularized by the time they enter the sensitivity band of the LIGO-Virgo-KAGRA (LVK) network. However, certain formation channels predict that in future observing runs (O4 and beyond), a fraction of detectable binaries could enter the sensitivity band with a measurable eccentricity $e$. Constraining $e$ for each GW event with Bayesian parameter estimation methods is computationally expensive and time-consuming. This motivates the need for a machine learning based identification and classification scheme, which could weed out the majority of GW events as non-eccentric and drastically reduce the set of candidate eccentric GWs. As a proof of principle, we train a separable-convolutional neural network (SCNN) with spectrograms of synthetic GWs added to Gaussian noise characterized by O4 representative PSDs. We use the trained network to (i) segregate candidates as either eccentric or non-eccentric (henceforth called the detection problem) and (ii) classify the events as non-eccentric $(e = 0)$, moderately eccentric $(e \in (0, 0.2])$, and highly eccentric $(e \in (0.2, 0.5])$. On the detection problem, our best performing network detects eccentricity with $0.986$ accuracy and true and false positive rates of $0.984$ and $1.6\times 10^{-3}$, respectively. On the classification problem, the best performing network classifies signals with $0.962$ accuracy. We also find that our trained classifier displays close to ideal behavior for the data we consider.

We investigate the non-perturbatively generated axion-like particle (ALP) potential, involving fermions in the dark sector that couple to the ALP, in an early cosmological inflationary stage with the ALP being a spectator field. The potential here deviates from the standard cosine nature due to the presence of the two fermion masses $m_u$ and $m_d$ which couple to the ALP. The ALP is a spectator field during inflation but it starts to oscillate and dominates the energy density of the universe after inflation ends, thereby sourcing isocurvature perturbations, while standard curvature fluctuations form the inflaton are assumed to be sub-dominant. Subsequently the ALP decays converting the isocurvature perturbations to adiabatic perturbations thereby acting as the origin of the primordial density perturbations. We identify the parameter space involving the axion decay constant $f_a$, scale of confinement $\Lambda$, ALP mass $m$ and the masses of the fermions, $m_u$ and $m_d$ where it can satisfactorily behave as the curvaton and source the observed primordial density perturbation. We also predict local non-Gaussianity signals for bi-spectrum and tri-spectrum $f_{NL}$ and $g_{NL}$, as a function of the ratio $m_u/m_d$, which are within the allowed range in the latest Planck observations and are detectable with future observations. Particularly we observed that the value of $f_{NL}$ and $g_{NL}$ are dependent on the ratio of $m_u$ and $m_d$: $f_{NL}$ is more or less positive for all scenarios except $m_u = m_d$ and $g_{NL}$ is always positive irrespective of the ratio between $m_u$ and $m_d$. The results of our analysis in the limit $m_u = m_d$ resembles vanilla curvaton scenario while in the limit $m_u \gg m_d$ resembles pure axion cosine potential.