Papers for Wednesday, Aug 10 2022

The ESPRESSO spectrograph at ESO's Very Large Telescope (VLT) has, since it began science operations in October 2018, revolutionised exoplanet science. The combination of the large VLT mirrors and the high resolution and stability of the spectrograph is enabling the detection of small, low-mass planets as well as detailed studies of the planets' atmospheres. In this article, we present a brief overview of the first results from ESPRESSO and a hopeful glimpse towards the ultimate goal of reaching the radial velocity precision of 10 cm/s needed to detect an Earth-like planet.

We use the SED-fitting code Prospector to reconstruct the nonparametric star formation history (SFH) of massive ($\log M_*>10.3$) star-forming galaxies (SFGs) and quiescent galaxies (QGs) at redshift $z_{\rm{obs}}\sim2$ to investigate the joint evolution of star-formation activity and structural properties. We find significant correlations between the SFH of the galaxies and their morphology. Compared to extended SFGs, compact SFGs are more likely to have experienced multiple star-formation episodes, with the fractional mass formed during the older ($\ge1$ Gyr) episode being larger, suggesting that high-redshift SFGs assembled their central regions earlier and then kept growing in central mass as they become more compact. The SFH of compact QGs does not significantly differ from the average for this category, and shows an early burst followed by a gradual decline of the star formation rate. The SFH of extended QGs, however, is similar to that of post-starburst galaxies and their morphology is also frequently disturbed. Knowledge of the SFH also enables us to empirically reconstruct the structural evolution of individual galaxies. While the progenitor effect is clearly observed and accounted for in our analysis, it alone is insufficient to explain the observed structural evolution. We show that, as they evolve from star-forming phase to quiescence, galaxies grow massive dense stellar cores. Quenching begins at the center and then propagates outward to the rest of the structure. We discuss possible physical scenarios for the observed evolution and find that our empirical constraints are in good quantitative agreement with the model predictions from dissipative accretion of gas to the center followed by massive starbursts before final quiescence (wet compaction).

The condensation of baryons within a dark matter (DM) halo during galaxy formation should result in some contraction of the halo as the combined system settles into equilibrium. We quantify this effect on the cuspy primordial halos predicted by DM-only simulations for the baryon distributions observed in the galaxies of the SPARC database. We find that the DM halos of high surface brightness galaxies (with $\Sigma_{\rm eff}\gtrsim100$ $L_\odot$ pc$^{-2}$ at 3.6 $\mu$m) experience strong contraction. Halos become more cuspy as a result of compression: the inner DM density slope increases with the baryonic surface mass density. We iteratively fit rotation curves to find the balance between initial halo parameters (constrained by abundance matching), compression, and stellar mass-to-light ratio. The resulting fits often require lower stellar masses than expected for stellar populations, particularly in galaxies with bulges: stellar mass must be reduced to make room for the DM it compresses. This trade off between dark and luminous mass is reminiscent of the cusp-core problem in dwarf galaxies, but occurs in more massive systems: the present-epoch DM halos cannot follow from cuspy primordial halos unless (1) the stellar mass-to-light ratios are systematically smaller than expected from standard stellar population synthesis models, and/or (2) there is a net outward mass redistribution from the initial cusp, even in massive galaxies widely considered to be immune from such effects.

Modern Galactic surveys have revealed an ancient merger that dominates the stellar halo of our Galaxy (\textit{Gaia}-Sausage-Enceladus, GSE). Using chemical abundances and kinematics from the H3 Survey, we identify 5559 halo stars from this merger in the radial range $r_{\text{Gal}}=6-60\text{ kpc}$. We forward model the full selection function of H3 to infer the density profile of this accreted component of the stellar halo. We consider a general ellipsoid with principal axes allowed to rotate with respect to the Galactocentric axes, coupled with a multiply-broken power law. The best-fit model is a triaxial ellipsoid (axes ratios 10:8:7) tilted $25^\circ$ above the Galactic plane towards the Sun and a doubly-broken power law with breaking radii at 12 kpc and 28 kpc. This result resolves the long-standing dichotomy in literature values of the halo breaking radius, being at either $\sim15\text{ kpc}$ or $\sim30\text{ kpc}$ assuming a singly-broken power law. N-body simulations suggest that the breaking radii are connected to apocenter pile-ups of stellar orbits, and so the observed double-break provides new insight into the initial conditions and evolution of the GSE merger. Furthermore, the tilt and triaxiality of the stellar halo could imply that a fraction of the underlying dark matter halo is also tilted and triaxial. This has important implications for dynamical mass modeling of the Galaxy as well as direct dark matter detection experiments.

In this work we publish stellar velocity dispersions, sizes, and dynamical masses for 8 ultra-massive galaxies (UMGs; log($M$/M$_\odot>11$, $z\gtrsim3$) from the Massive Ancient Galaxies At $z>3$ NEar-infrared (MAGAZ3NE) Survey, more than doubling the number of such galaxies with velocity dispersion measurements at this epoch. Using the deep Keck/MOSFIRE and Keck/NIRES spectroscopy of these objects in the $H$- and $K$-bandpasses, we obtain large velocity dispersions of $\sim400$ km s$^{-1}$ for most of the objects, which are some of the highest stellar velocity dispersions measured, and $\sim40$\% larger than those measured for galaxies of similar mass at $z\sim1.7$. The sizes of these objects are also smaller by a factor of 1.5-3 compared to this same $z\sim1.7$ sample. We combine these large velocity dispersions and small sizes to obtain dynamical masses. The dynamical masses are similar to the stellar masses of these galaxies, consistent with a Chabrier initial mass function (IMF). Considered alongside previous studies of massive quiescent galaxies across $0.2<z<4.0$, there is evidence for an evolution in the relation between the dynamical mass - stellar mass ratio and velocity dispersion as a function of redshift. This implies an IMF with fewer low mass stars (e.g., Chabrier IMF) for massive quiescent galaxies at higher redshifts in conflict with the bottom-heavy IMF (e.g., Salpeter IMF) found in their likely $z\sim0$ descendants, though a number of alternative explanations such as a different dynamical structure or significant rotation are not ruled out. Similar to data at lower redshifts, we see evidence for an increase of IMF normalization with velocity dispersion, though the $z\gtrsim3$ trend is steeper than that for $z\sim0.2$ early-type galaxies and offset to lower dynamical-to-stellar mass ratios.

Protoplanetary discs are crucial to understanding how planets form and evolve, but these objects are subject to the vagaries of the birth environments of their host stars. In particular, photoionising radiation from massive stars has been shown to be an effective agent in disrupting protoplanetary discs. External photoevaporation leads to the inward evolution of the radii of discs, whereas the internal viscous evolution of the disc causes the radii to evolve outwards. We couple N-body simulations of star-forming regions with a post-processing analysis of disc evolution to determine how the radius and mass distributions of protoplanetary discs evolve in young star-forming regions. To be consistent with observations, we find that the initial disc radii must be of order 100au, even though these discs are readily destroyed by photoevaporation from massive stars. Furthermore, the observed disc radii distribution in the Orion Nebula Cluster is more consistent with moderate initial stellar densities (100M$_\odot$ pc$^{-3}$), in tension with dynamical models that posit much higher inital densities for the ONC. Furthermore, we cannot reproduce the observed disc radius distribution in the Lupus star-forming region if its discs are subject to external photoevaporation. A more detailed comparison is not possible due to the well-documented uncertainties in determining the ages of pre-main sequence (disc-hosting) stars.

RR Lyrae are a well-known class of pulsating horizontal branch stars widely used as tracers of old, metal-poor stellar populations. However, mounting observational evidence shows that a significant fraction of these stars may be young and metal-rich. Here, through detailed binary stellar evolution modelling, we show that all such metal-rich RR Lyrae can be naturally produced through binary interactions. Binary companions of such RR Lyrae partly strip their progenitor's envelopes during a preceding red giant phase. As a result, stripped horizontal branch stars become bluer compared to their isolated stellar evolution counterparts and thus end up in the instability strip. In contrast, in the single evolution scenario, the stars can attain such colours only at large age and low metallicity. While RR Lyrae from binary evolution generally can have any ages and metallicities, the Galactic population is relatively young (1 - 9 Gyr) and dominated by the Thin Disc and the Bulge. We show that Galactic RR Lyrae from binary evolution are produced at rates compatible with the observed metal-rich population and have consistent G-band magnitudes, Galactic kinematics and pulsation properties. Furthermore, these systems dominate the RR Lyrae population in the Solar Neighbourhood. We predict that all metal-rich RR Lyrae have a long-period (P > 1000 d) A, F, G or K-type companion. Observationally characterising the orbital periods and masses of such stellar companions will provide valuable new constraints on mass and angular momentum-loss efficiency for Sun-like accretors and the nature of RR Lyrae populations.

Water vapor (H$_{2}$O) is one of the brightest molecular emitters after carbon monoxide (CO) in galaxies with high infrared (IR) luminosity, and allows us to investigate the warm dense phase of the interstellar medium (ISM) where star formation occurs. However, due to the complexity of its radiative spectrum, H$_{2}$O is not frequently exploited as an ISM tracer in distant galaxies. Therefore, H$_{2}$O studies of the warm and dense gas at high-$z$ remains largely unexplored. In this work we present observations conducted with the Northern Extended Millimeter Array (NOEMA) toward three $z>6$ IR-bright quasars J2310+1855, J1148+5251, and J0439+1634 targeted in their multiple para-/ortho-H$_{2}$O transitions ($3_{12}-3_{03}$, $1_{11}-0_{00}$, $2_{20}-2_{11}$, and $4_{22}-4_{13}$), as well as their far-IR (FIR) dust continuum. By combining our data with previous measurements from the literature we estimate dust masses and temperatures, continuum optical depths, IR luminosities, and the star-formation rates from the FIR continuum. We model the H$_{2}$O lines using the MOLPOP-CEP radiative transfer code and find that water vapor lines in our quasar host galaxies are primarily excited in warm dense (gas kinetic temperature and density of $T_{\rm kin} = 50\,{\rm K}$, $n_{\rm H_{2}}\sim 10^{4.5}-10^{5}\,{\rm cm^{-3}}$) molecular medium with water vapor column density of $N_{\rm H_{2}O}\sim 2\times10^{17}-3\times10^{18}\,{\rm cm^{-3}}$. High-$J$ H$_{2}$O lines are mainly radiatively pumped by the intense optically-thin far-IR radiation field associated with a warm dust component with temperatures of $T_{\rm dust}\sim 80-190\,{\rm K}$ that account for $<5-10\%$ of the total dust mass. Our results are in agreement with expectations based on the H$_{2}$O spectral line energy distribution of local and high-$z$ ultra-luminous IR galaxies and AGN. [abridged]

The 1215.67A HI Lyman alpha emission line dominates the ultraviolet flux of low mass stars, including the majority of known exoplanet hosts. Unfortunately, strong attenuation by the interstellar medium (ISM) obscures the line core at most stars, requiring the intrinsic Lyman alpha flux to be reconstructed based on fits to the line wings. We present a test of the widely-used Lyman alpha emission line reconstruction code LYAPY using phase-resolved, medium-resolution STIS G140M observations of the close white dwarf-M dwarf binary EG UMa. The Doppler shifts induced by the binary orbital motion move the Lyman alpha emission line in and out of the region of strong ISM attenuation. Reconstructions to each spectrum should produce the same Lyman alpha profile regardless of phase, under the well-justified assumption that there is no intrinsic line variability between observations. Instead, we find that the reconstructions underestimate the Lyman alpha flux by almost a factor of two for the lowest-velocity, most attenuated spectrum, due to a degeneracy between the intrinsic Lyman alpha and ISM profiles. Our results imply that many stellar Lyman alpha fluxes derived from G140M spectra reported in the literature may be underestimated, with potential consequences for, for example, estimates of extreme-ultraviolet stellar spectra and ultraviolet inputs into simulations of exoplanet atmospheres.

Optically luminous quasars are metal rich across all redshifts. Surprisingly, there is no significant trend in the broad-line region (BLR) metallicity with different star formation rates (SFR). The average N V/ C IV metallicity does not exceed $9.5~Z_\odot$ and the average Si IV/ C IV metallicity is similarly $\sim10~Z_\odot$. Combined, these observations are indicative of a metallicity ceiling. Here, we study whether a metallicity ceiling can exist in quasar disks due to the evolution of embedded stars. We develop a simple model that starts with gas in a closed box, which is enriched by cycles of stellar evolution until eventually newly formed stars undergo significant mass loss before they reach the supernovae stage and no further enrichment is possible. Using the MESA code, we create a grid over a parameter space of masses ($>8~M_\odot$) and metallicities ($1-10~Z_\odot$), and locate portions of the parameter space where mass loss via winds occurs on a timescale shorter than the lifetime of the stars. We find that for reasonable assumptions about stellar winds, sufficiently massive ($8-22~M_\odot$) and metal-rich ($\sim9~Z_\odot$) stars lose significant mass via winds and fail to evolve to the supernovae stage, thereby failing to enrich and increase the metallicity of their surroundings. This suggests that a metallicity ceiling is the final state of a closed-box system of gas and stars.

In flare-relevant current sheets, tearing instability may trigger explosive reconnection and plasmoid formation. We explore how the thermal and tearing modes reinforce each other in the fragmentation of a current sheet in the solar corona through an explosive reconnection process, characterized by the formation of plasmoids which interact and trap condensing plasma. We use a resistive magnetohydrodynamic (MHD) simulation of a 2D current layer, incorporating the non-adiabatic effects of optically thin radiative energy loss and background heating using \texttt{MPI-AMRVAC}. Our parametric survey explores different resistivities and plasma-$\beta$ to quantify the instability growth rate in the linear and nonlinear regimes. We notice that for dimensionless resistivity values within $10^{-4} - 5 \times 10^{-3}$, we get explosive behavior where thermal instability and tearing behavior reinforce each other. This is clearly below the usual critical Lundquist number range of pure resistive explosive plasmoid formation. The non-linear growth rates follow weak power-law dependency with resistivity. The fragmentation of the current sheet and the formation of the plasmoids in the nonlinear phase of the evolution due to the thermal and tearing instabilities are obtained. The formation of plasmoids is noticed for the Lundquist number ($S_L$) range $4.6 \times 10^3 - 2.34 \times 10^5$. We quantify the temporal variation of the plasmoid numbers and the density filling factor of the plasmoids for different physical conditions. We also find that the maximum plasmoid numbers scale as $S_L^{0.223}$. Within the nonlinearly coalescing plasmoid chains, localized cool condensations gather, realizing density and temperature contrasts similar to coronal rain or prominences.

Here we investigate the kinematics of the part of the broad line region (BLR) in active galactic nuclei (AGNs) emitting H$\beta$ and H$\alpha$ emission lines. We explore the widths and asymmetries of the broad H$\beta$ and H$\alpha$ emission lines in a sample of high quality (i.e. high signal to noise ratio) spectra of type 1 AGN taken from the Data Release 16 of the Sloan Digital Sky Survey, in order to explore possible deviation from the gravitationally bound motion. To find only the broad component of H$\beta$ and H$\alpha$ we use the FANTASY (Fully Automated pythoN Tool for AGN Spectra analYsis) code for the multi-component modeling of the AGN spectra and for careful extraction of the broad emission line parameters. We show that based on the broad line profiles widths and asymmetries, the BLR gas emitting H$\beta$ and H$\alpha$ lines follows similar kinematics, and seems to be virialized in our sample of type 1 AGN.

One of the principal challenges of 21 cm cosmology experiments is overcoming calibration error. Established calibration approaches in the field require an exquisitely accurate sky model, and low-level sky model errors introduce calibration errors that corrupt the cosmological signal. We present a novel calibration approach called Delay-Weighted Calibration, or DWCal, that enables precise calibration even in the presence of sky model error. Sky model error does not affect all power spectrum modes equally, and DWCal fits calibration solutions preferentially from error-free modes. We apply this technique to simulated data, showing that it substantially reduces calibration error in the presence of realistic levels of sky model error and can improve 21 cm power spectrum sensitivity by approximately 2 orders of magnitude.

In spite that the Crab supernova in 1054 A.D. was studied over the years, it is still not clear what type of event produced the explosion. The most detailed and reliable source of the observed light curve is recorded in the Chinese and Japanese chronicles, and suggests a quick dimming after a very bright initial peak. We shall show in this work that the Crab event can be well explained by a type of precursor, a phenomenon emerging from large supernova sampling and quite expected from Stellar Evolution considerations of low-mass progenitors. This very early bright transient is followed by the explosion itself, likely a low-luminosity supernova from ``small iron core'' type instead of an electron-capture event. The latter conclusion stems from recent simulation work, which predict that an electron-capture supernova would render the magnitude to be much brighter for $\sim 3$ months, hence visible during daytime, and would not match the Chinese records.

The Hipparcos catalog provides the first epoch of the celestial reference frame (CRF) in the optical domain and serves as an indispensable tool to verify and improve the Gaia CRF for the brighter stars ($V<11$ mag) and to identify the elusive astrometric binary stars with dim or invisible companions, including long-period exoplanets. The systems of positions in Hipparcos and Gaia cannot be directly compared, because they refer to two different mean epochs. It is shown that the proper motion systems for carefully filtered common stars are not statistically consistent within the given formal errors. The vector field of proper motion differences is fitted with 126 vector spherical harmonics up to degree 7 revealing a global pattern at high signal-to-noise ratios, including the three terms of rigid rotation. The origin of the differential spin and other large harmonic terms is investigated by producing a similar decomposition of the Gaia$-$HG proper motion field, where HG stands for the long-term proper motions derived from the Hipparcos and Gaia DR3 positions, for the same sample of stars. Hipparcos proper motions emerge as the largest source of sky-correlated distortions of the multi-epoch optical CRF with a median value of $\sim 190$ $\mu$as yr$^{-1}$ and a global spin of $\sim 226$ $\mu$as yr$^{-1}$, while the Hipparcos positions and Gaia EDR3 proper motions are explicitly consistent by construction at a level of $\sim 10$ $\mu$as yr$^{-1}$. The latter, however, include multiple distortions of higher degree, which should be taken into account in astrometric applications using the HG field.

In the search for life beyond our Solar system, attention should be focused on those planets that have the potential to maintain habitable conditions over the prolonged periods of time needed for the emergence and expansion of life as we know it. The observable planetary architecture is one of the determinants for long-term habitability as it controls the orbital evolution and ultimately the stellar fluxes received by the planet. With an ensemble of n-body simulations and obliquity models of hypothetical planetary systems, we demonstrate that the amplitude and period of eccentricity, obliquity, and precession cycles of an Earth-like planet are sensitive to the orbital characteristics of a giant companion planet. A series of transient, ocean-coupled climate simulations show how these characteristics of astronomical cycles are decisive for the evolving surface conditions and long-term fractional habitability relative to the modern Earth. The habitability of Earth-like planets increases with the eccentricity of a Jupiter-like companion, provided that the mean obliquity is sufficiently low to maintain temperate temperatures over large parts of its surface throughout the orbital year. A giant companion closer in results in shorter eccentricity cycles of an Earth-like planet but longer, high-amplitude, obliquity cycles. The period and amplitude of obliquity cycles can be estimated to first order from the orbital pathways calculated by the n-body simulations. In the majority of simulations, obliquity amplitude relates directly to the orbital inclination whereas the period of obliquity cycles is a function of nodal precession and the proximity of a giant companion.

We identify a sample of 27 long-period comets for which both non-gravitational accelerations and Lyman-alpha based gas production rates are available. Seven of the 27 comets (i.e. 25 percent) did not survive perihelion because of nucleus fragmentation or complete disintegration. Empirically, the latter nuclei have the smallest gas production rates and the largest non-gravitational accelerations, which are both indicators of small size. Specifically, the disintegrating nuclei have a median radius of only 0.41 km, one quarter of the 1.60 km median radius of those surviving perihelion. The disintegrating comets also have a smaller median perihelion distance (0.48 au) than do the survivors (0.99 au). We compare the order of magnitude timescale for outgassing torques to change the nucleus spin, tau, with the time spent by each comet in strong sublimation, Dt, finding that the disrupted comets are those with tau < Dt. The destruction of near-Sun long-period comets is thus naturally explained as a consequence of rotational break-up. We discuss this process as a contributor to Oort's long mysterious ``fading parameter''.

The middle corona, the region roughly spanning heliocentric altitudes from $1.5$ to $6\,R_\odot$, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. Eruptions that could disrupt the near-Earth environment propagate through it. Importantly, it modulates inflow from above that can drive dynamic changes at lower heights in the inner corona. Consequently, this region is essential for comprehensively connecting the corona to the heliosphere and for developing corresponding global models. Nonetheless, because it is challenging to observe, the middle corona has been poorly studied by major solar remote sensing missions and instruments, extending back to the Solar and Heliospheric Observatory (SoHO) era. Thanks to recent advances in instrumentation, observational processing techniques, and a realization of the importance of the region, interest in the middle corona has increased. Although the region cannot be intrinsically separated from other regions of the solar atmosphere, there has emerged a need to define the region in terms of its location and extension in the solar atmosphere, its composition, the physical transitions it covers, and the underlying physics believed to be encapsulated by the region. This paper aims to define the middle corona and give an overview of the processes that occur there.

The Vera C. Rubin Legacy Survey of Space and Time holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey's first light.

The possibility to observe transiting exoplanets from Dome C in Antarctica provides immense benefits: stable weather conditions, limited atmospheric turbulence, and a night that lasts almost three months due to the austral winter. However, this site also presents significant limitations, such as limited access for maintenance and internet speeds of only a few KB/s. This latter factor means that the approximately 6 TB of data collected annually must be processed on site automatically, with only final data products being sent once a day to Europe. In this context, we present the current state of operations of ASTEP+, a 40 cm optical telescope located at Concordia Station in Antarctica. Following a successful summer campaign, ASTEP+ has begun the 2022 observing season with a brand-new two-colour photometer with increased sensitivity. A new Python data analysis pipeline installed on a dedicated server in Concordia will significantly improve the precision of the extracted photometry, enabling us to get higher signal-to-noise transit detections. The new pipeline additionally incorporates automatic transit modelling to reduce the amount of manual post-processing required. It also handles the automatic daily transfer of the photometric lightcurves and control data to Europe. Additionally, we present the Python and web-based systems used for selection and scheduling of transit observations; these systems have wide applicability for the scheduling of other astronomical observations with strong time constraints. We also review the type of science that ASTEP+ will be conducting and analyse how unique ASTEP+ is to exoplanet transit research.

We investigate physical reasons for high dust temperatures ($T_\mathrm{dust}\gtrsim 40$ K) observed in some high-redshift ($z>5$) galaxies using analytic models. We consider two models that can be treated analytically: the radiative transfer (RT) model, {where a broad distribution of values for $T_\mathrm{dust}$ is considered}, and the one-tempearture (one-$T$) model, which assumes {uniform $T_\mathrm{dust}$}. These two extremes {serve to bracket the most realistic scenario}. We adopt the Kennicutt--Schmidt (KS) law to relate stellar radiation field to gas surface density, and vary the dust-to-gas ratio. As a consequence, our model is capable of predicting the relation between the surface density of star formation rate ($\Sigma_\mathrm{SFR}$) or dust mass ($\Sigma_\mathrm{dust}$) and $T_\mathrm{dust}$. We show that the high $T_\mathrm{dust}$ observed at $z\gtrsim 5$ favour low dust-to-gas ratios ($\lesssim 10^{-3}$). An enhanced star formation compared with the KS law gives an alternative explanation for the high $T_\mathrm{dust}$. The dust temperatures are similar between the two (RT and one-$T$) models as long as we use ALMA Bands 6--8. We also examine the relation among $\Sigma_\mathrm{SFR}$, $\Sigma_\mathrm{dust}$ and $T_\mathrm{dust}$ without assuming the KS law, and confirm the consistency with the actual observational data at $z>5$. In the one-$T$ model, we also examine a clumpy dust distribution, which predicts lower $T_\mathrm{dust}$ because of the leakage of stellar radiation. This enhances the requirement of low dust abundance or high star formation efficiency to explain the observed high $T_\mathrm{dust}$.

The ASTRI Mini-Array (MA) is an INAF project to build and operate a facility to study astronomical sources emitting at very high-energy in the TeV spectral band. The ASTRI MA consists of a group of nine innovative Imaging Atmospheric Cherenkov telescopes. The telescopes will be installed at the Teide Astronomical Observatory of the Instituto de Astrofisica de Canarias (IAC) in Tenerife (Canary Islands, Spain) on the basis of a host agreement with INAF. Thanks to its expected overall performance, better than those of current Cherenkov telescopes' arrays for energies above \sim 5 TeV and up to 100 TeV and beyond, the ASTRI MA will represent an important instrument to perform deep observations of the Galactic and extra-Galactic sky at these energies.

Markov Chain Monte Carlo approach is frequently used within Bayesian framework to sample the target posterior distribution. Its efficiency strongly depends on the proposal used to build the chain. The best jump proposal is the one that closely resembles the unknown target distribution, therefore we suggest an adaptive proposal based on Kernel Density Estimation (KDE). We group parameters of the model according to their correlation and build KDE based on the already accepted points for each group. We adapt the KDE-based proposal until it stabilizes. We argue that such a proposal could be helpful in applications where the data volume is increasing and in the hyper-model sampling. We tested it on several astrophysical datasets (IPTA and LISA) and have shown that in some cases KDE-based proposal also helps to reduce the autocorrelation length of the chains. The efficiency of this proposal is reduces in case of the strong correlations between a large group of parameters.

Since the discovery of pulsars, dozens of surveys have already been conducted with their searches. In the course of surveys in the sky, areas from thousands to tens of thousands of square degrees are explored. Despite repeated observations of the same areas, new pulsars are constantly being discovered. We present Pushchino Multibeam Pulsar Search (PUMPS), having a sensitivity that is an order of magnitude higher than the sensitivity of all previously made surveys on pulsar search. In PUMPS daily round-the-clock observations are carried out of the area located on declinations $-9^o < \delta < +42^o$. The survey is carried out on 96 beams of a Large Phased Array (LPA) at a frequency of 111 MHz. During the observation period of August 2014 - August 2022, the survey was repeated approximately 3,000 times. The expected sensitivity in the survey reaches up to 0.1 mJy. The paper considers some tasks that can be solved when processing the received data.

Radio observations of low-mass star formation in molecular spectral lines have rapidly progressed since the advent of Atacama Large Millimeter/submillimeter Array (ALMA). A gas distribution and its kinematics within a few 100s au scale around a Class 0-I protostar are spatially resolved, and the region where a protostellar disk is being formed is now revealed in detail. In such studies, it is essential to characterize the complex physical structure around a protostar consisting of an infalling envelope, a rotationally-supported disk, and an outflow. For this purpose, we have developed a general-purpose computer code `{\tt FERIA}' (Flat Envelope model with Rotation and Infall under Angular momentum conservation) generating the image cube data based on the infalling-rotating envelope model and the Keplerian disk model, both of which are often used in observational studies. In this paper, we present the description and the usage manual of {\tt FERIA} and summarize caveats in actual applications. This program outputs cube {\tt FITS} files, which can be used for direct comparison with observations. It can also be used to generate mock data for the machine/deep learnings. Examples of these applications are described and discussed to demonstrate how the model analyses work with actual observational data.

Kernel phase is a method to interpret stellar point source images by considering their formation as the analytical result of an interferometric process. Using Fourier formalism, this method allows for observing planetary companions around nearby stars at separations down to half a telescope resolution element, typically 20\,mas for a 8\,m class telescope in H band. The Kernel-phase analysis has so far been mainly focused on working with a single monochromatic light image, recently providing theoretical contrast detection limits down to $10^{-4}$ at 200\,mas with JWST/NIRISS in the mid-infrared by using hypothesis testing theory. In this communication, we propose to extend this approach to data cubes provided by integral field spectrographs (IFS) on ground-based telescopes with adaptive optics to enhance the detection of planetary companions and explore the spectral characterization of their atmosphere by making use of the Kernel-phase multi-spectral information. Using ground-based IFS data cube with a spectral resolution R=20, we explore different statistical tests based on kernel phases at three wavelengths to estimate the detection limits for planetary companions. Our tests are first conducted with synthetic data before extending their use to real images from ground-based exoplanet imagers such as Subaru/SCExAO and VLT/SPHERE in the near future. Future applications to multi-wavelength data from space telescopes are also discussed for the observation of planetary companions with JWST.

'Red nuggets' are a rare population of passive compact massive galaxies thought to be the first massive galaxies that formed in the Universe. First found at $z \sim 3$, they are even less abundant at lower redshifts, and it is believed that with time they mostly transformed through mergers into today's giant ellipticals. Those red nuggets which managed to escape this fate can serve as unique laboratories to study the early evolution of massive galaxies. In this paper, we aim to make use of the VIMOS Public Extragalactic Redshift Survey to build the largest up-to-date catalogue of spectroscopically confirmed red nuggets at the intermediate redshift $0.5<z<1.0$. Starting from a catalogue of nearly 90 000 VIPERS galaxies we select sources with stellar masses $M_{star} > 8\times10^{10}$ $\rm{M}_\odot$ and effective radii $R_\mathrm{e}<1.5$ kpc. Among them, we select red, passive galaxies with old stellar population based on colour--colour NUVrK diagram, star formation rate values, and verification of their optical spectra. Verifying the influence of the limit of the source compactness on the selection, we found that the sample size can vary even up to two orders of magnitude, depending on the chosen criterion. Using one of the most restrictive criteria with additional checks on their spectra and passiveness, we spectroscopically identified only 77 previously unknown red nuggets. The resultant catalogue of 77 red nuggets is the largest such catalogue built based on the uniform set of selection criteria above the local Universe. Number density calculated on the final sample of 77 VIPERS passive red nuggets per comoving Mpc$^3$ increases from 4.7$\times10^{-6}$ at $z \sim 0.61$ to $9.8 \times 10^{-6}$ at $z \sim 0.95$, which is higher than values estimated in the local Universe, and lower than the ones found at $z>2$. It fills the gap at intermediate redshift.

Primordial black holes (PBHs) can be produced in the very early Universe due to the large density fluctuations. The cosmic background of axion-like particles (ALPs) could be non-thermally generated by PBHs. In this paper, we investigate the ALPs emitted by ultra-light PBHs with the mass range $10 \, {\rm g} \lesssim M_{\rm PBH} \lesssim 10^9 \, \rm g$, in which PBHs would have completely evaporated before the start of Big Bang Nucleosynthesis (BBN) and can therefore not be directly constrained. In this case, the minimal scenario that ALPs could interact only with photons is supposed. We study the stochastic oscillations between ALPs and photons in the cosmic magnetic field. The primordial magnetic field (PMF) is considered as the stochastic background field model with the non-helical and helical components. Using the PMF limits derived from the Planck 2015 data, we show the numerical results of ALP-photon oscillation probability distributions with the homogeneous and stochastic magnetic field scenarios. The PBH-induced ALP-photon oscillations in the PMF may have the effects on some further phenomena, such as the cosmic microwave background (CMB), the cosmic X-ray background (CXB), and the extragalactic gamma-ray background.

The focus of this paper is on inclination-only dependent lunisolar resonances, which shape the dynamics of a MEO (Medium Earth Orbit) object over secular time scales (i.e. several decades). Following the formalism of arXiv:2107.14507, we discuss an analytical model yielding the correct form of the separatrices of each one of the major lunisolar resonances in the "action" space $(i, e)$ (inclination, eccentricity) for any given semi-major axis $a$. We then highlight how our method is able to predict and explain the main structures found numerically in Fast Lyapunov Indicator (FLI) cartography. We focus on explaining the dependence of the FLI maps from the initial phase of the argument of perigee $\omega$ and of the longitude of the ascending node $\Omega$ of the object and of the moon $\Omega_L$. In addition, on the basis of our model, we discuss the role played by the $\Omega-\Omega_L$ and the $2 \Omega-\Omega_L$ resonances, which overlap with the inclination-only dependent ones as they sweep the region for increasing values of $a$, generating large domains of chaotic motion. Our results provide a framework useful in designing low-cost satellite deployment or space debris mitigation strategies, exploiting the natural dynamics of lunisolar resonances that increase an object's eccentricity up until it reaches a domain where friction leads to atmospheric re-entry.

Spectral analysis of the spatial structure of solar subphotospheric convection is carried out for subsurface flow maps constructed using the time--distance helioseismological technique. The source data are obtained from the Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO) from 2010 May to 2020 September. A spherical-harmonic transform is applied to the horizontal-velocity-divergence field at depths from 0 to 19~Mm. The range of flow scales is fairly broad in shallow layers and narrows as the depth increases. The horizontal flow scales rapidly increase with depth, from supergranulation to giant-cell values, and indicate the existence of large-scale convective motions in the near-surface shear layer. The results can naturally be interpreted in terms of a superposition of differently scaled flows localized in different depth intervals. There is some tendency toward the emergence of meridionally elongated (banana-shaped) convection structures in the deep layers. The total power of convective flows is anticorrelated with the sunspot-number variation over the solar activity cycle in shallow subsurface layers and positively correlated at larger depths, which is suggestive of the depth redistribution of the convective-flow energy due to the action of magnetic fields.

Mass composition is important for understanding the origin of ultra-high-energy cosmic rays. However, interpretation of mass composition from air shower experiments is challenging, owing to significant uncertainty in hadronic interaction models adopted in air shower simulation. A particular source of uncertainty is diffractive dissociation, as its measurements in accelerator experiments demonstrated significant systematic uncertainty. In this research, we estimate the uncertainty in $\langle X_{\rm max}\rangle$ from the uncertainty of the measurement of diffractive dissociation by the ALICE experiment. The maximum uncertainty size of the entire air shower was estimated to be $^{+4.0}_{-5.6}~\mathrm{g/cm^2}$ for air showers induced by $10^{17}$~eV proton, which is not negligible in the uncertainty of $\langle X_{\rm max}\rangle$ predictions.

The NIRSpec instrument on the James Webb Space Telescope (JWST) brings the first multi-object spectrograph (MOS) into space, enabled by a programmable Micro Shutter Array (MSA) of ~250,000 individual apertures. During the 6-month Commissioning period, the MSA performed admirably, completing ~800 reconfigurations with an average success rate of ~96% for commanding shutters open in science-like patterns. We show that 82.5% of the unvignetted shutter population is usable for science, with electrical short masking now the primary cause of inoperable apertures. In response, we propose a plan to recheck existing shorts during nominal operations, which is expected to reduce the number of affected shutters. We also present a full assessment of the Failed Open and Failed Closed shutter populations, which both show a marginal increase in line with predictions from ground testing. We suggest an amendment to the Failed Closed shutter flagging scheme to improve flexibility for MSA configuration planning. Overall, the NIRSpec MSA performed very well during Commissioning, and the MOS mode was declared ready for science operations on schedule.

Time-resolved polarizations carry more physical information about the source of gamma-ray bursts (GRBs) than the time-integrated ones. Therefore, they give more strict constrains on the models of GRB prompt phase. Both time-resolved and time-integrated polarizations are considered here. The model we use is the synchrotron emission in a large-scale ordered aligned magnetic field. Time-resolved polarizations of GRB prompt phase are derived with the corresponding time-resolved energy spectra. We found the time-integrated PDs calculated with two methods are similar. So it is convenient to estimate the time-integrated PD by the time-integrated energy spectrum. Most of the time-resolved PDs calculated in this paper will increase with time. The trend could match the observed time-resolved PD curve of GRB 170114A, but contrary to the predictions of a decaying PD of both the magnetized internal shock and magnetic reconnection models. PAs calculated in this paper, in general, are roughly constants with time. The predicted PAs here can not match with the violent PA changes observed in GRB 100826A and GRB 170114A. Therefore, more accurate time-resolved polarization observations are needed to test models and to diagnose the true physical process of GRB prompt phase.

We present the discovery of 528.6 Hz pulsations in the new X-ray transient MAXI J1816-195. Using NICER, we observed the first recorded transient outburst from the neutron star low-mass X-ray binary MAXI J1816-195 over a period of 28 days. From a timing analysis of the 528.6 Hz pulsations, we find that the binary system is well described as a circular orbit with an orbital period of 4.8 hours and a projected semi-major axis of 0.26 light-seconds for the pulsar, which constrains the mass of the donor star to $0.10-0.55 M_\odot$. Additionally, we observed 15 thermonuclear X-ray bursts showing a gradual evolution in morphology over time, and a recurrence time as short as 1.4 hours. We did not detect evidence for photospheric radius expansion, placing an upper limit on the source distance of 8.6 kpc.

We report results of our upgraded giant metrewave radio telescope (uGMRT) observations of an early-stage merging cluster, CIZA J1358.9-4750 (CIZA1359), in Band-3 (300--500 MHz). We achieved the image dynamic range of $\sim 17,000$ using the direction dependent calibration and found a diffuse source candidate at 4~$\sigma_{rms}$ significance. The flux density of this candidate is $24.04 \pm 2.48$~mJy at 400~MHz, which is sufficiently positive compared to noise. The radio power of the candidate is $2.40 \times 10^{24}$~W~Hz$^{-1}$, which is consistent with those of typical diffuse cluster emissions. The diffuse radio source candidate is associated with a part of a X-ray shock front where the Mach number reaches its maximum value of $\mathcal{M}\sim 1.7$. The observed spectral index ($F_\nu \propto \nu^{\alpha}$) of this source is $\alpha = - 1.06 \pm 0.33$ which consistent with the spectral index expected by the standard diffusive shock acceleration (DSA) model, but such a low Mach number with a short acceleration time would require seed cosmic-rays supplied from past active galactic nucleus (AGN) activities of member galaxies, as suggested in some other clusters. We found seven possible seeded radio sources in the same region as the candidates, which supports a model of radio emission with seeding. The magnetic field strength of this candidate was estimated assuming the energy equipartition between magnetic fields and cosmic-rays to be $2.1~\mu$G. We also find head-tail galaxies and radio phoenixes or fossils near the CIZA1359.

We present high-resolution dayside thermal emission observations of the exoplanet KELT-20b/MASCARA-2b using the MAROON-X spectrograph. Applying the cross-correlation method with both empirical and theoretical masks and a retrieval analysis, we confirm previous detections of Fe\,\textsc{i} emission lines and we detect Ni\,\textsc{i} for the first time in the planet (at 4.7$\sigma$ confidence). We do not see evidence for additional species in the MAROON-X data, including notably predicted thermal inversion agents TiO and VO, their atomic constituents Ti\,\textsc{i} and V\,\textsc{i}, and previously claimed species Fe\,\textsc{ii} and Cr\,\textsc{i}. We also perform a joint retrieval with existing \textit{Hubble Space Telescope}/WFC3 spectroscopy and \textit{Spitzer}/IRAC photometry. This allows us to place bounded constraints on the abundances of Fe\,\textsc{i}, H$_2$O, and CO, and to place a stringent upper limit on the TiO abundance. The results are consistent with KELT-20b having a solar to slightly super-solar composition atmosphere in terms of the bulk metal enrichment, and the carbon-to-oxygen and iron-to-oxygen ratios. However, the TiO volume mixing ratio upper limit (10$^{-7.6}$ at 99\% confidence) is inconsistent with this picture, which, along with the non-detection of Ti\,\textsc{i}, points to sequestration of Ti species, possibly due to nightside condensation. The lack of TiO but the presence of a large H$_2$O emission feature in the WFC3 data is challenging to reconcile within the context of 1D self-consistent, radiative-convective models.

We present Swift observations of 31 sources from the SMS4 catalog, a sample of 137 bright radio sources in the southern hemisphere. All these sources had no Chandra or XMM-Newton observations: 24 of these were observed with Swift through a dedicated proposal in 2015, and data for the remaining seven were retrieved from the Swift archive. The reduction and analysis of data collected by the Swift X-ray Telescope (XRT) led to twenty detections in the 0.3--10 keV band. We provide details of the X-ray emission in this band for these twenty detections, as well as upper limits for the remaining eleven SMS4 sources. When statistics allowed, we investigated the extent of the X-ray emission, the hardness ratio, and we carried out a spectral analysis. We matched the twenty X-ray detected sources with infrared (AllWISE, CatWISE2020) and optical (GSC 2.3.2, DES DR2) catalogs to establish associations with infrared and optical sources, and compared our results with previously published counterparts in these bands. Requiring a detection in both the infrared and the optical bands to establish a candidate counterpart for our X-ray detections, we obtain reliable counterparts for eighteen sources, while the remaining two sources need further investigation to establish firm identifications. We find that ~35% of all the SMS4 sources lie below the lower limit of 10.9 Jy for the flux density at 178 MHz. We present the list of 56 SMS4 sources that in March 2022 remain to be observed in the X-rays with narrow-field instruments.

PG 1159-035 is the prototype of the DOV hot pre-white dwarf pulsators. It was observed during the Kepler satellite K2 mission for 69 days in 59 s cadence mode and by the TESS satellite for 25 days in 20 s cadence mode. We present a detailed asteroseismic analysis of those data. We identify a total of 107 frequencies representing 32 l=1 modes, 27 frequencies representing 12 l=2 modes, and 8 combination frequencies. The combination frequencies and the modes with very high k values represent new detections. The multiplet structure reveals an average splitting of 4.0+/-0.4 muHz for l=1 and 6.8+/-0.2 muHz for l=2, indicating a rotation period of 1.4+/-0.1 days in the region of period formation. In the Fourier transform of the light curve, we find a significant peak at 8.904+/-0.003 muHz suggesting a surface rotation period of 1.299+/-0.002 days. We also present evidence that the observed periods change on timescales shorter than those predicted by current evolutionary models. Our asteroseismic analysis finds an average period spacing for l=1 of 21.28+/-0.02 s. The l=2 modes have a mean spacing of 12.97+/-0.4 s. We performed a detailed asteroseismic fit by comparing the observed periods with those of evolutionary models. The best fit model has Teff=129600+/- 11100 K, mass M*=0.565+/-0.024 Msun, and log g=7.41+0.38-0.54, within the uncertainties of the spectroscopic determinations. We argue for future improvements in the current models, e.g., on the overshooting in the He-burning stage, as the best-fit model does not predict excitation for all the pulsations detected in PG~1159-03.

The origin and evolution of Martian moons have been intensively debated in recent years. It is proposed that Phobos and Deimos may originate directly from a splitting of an ancestor moon orbiting at around the Martian synchronous orbit. At this hypothetical splitting, the apocenter of the inner moon (presumed as Phobos) and the pericenter of the outer moon (presumed as Deimos) are reported to coincide, in that, their semi-major axes reside inside and outside the Martian synchronous orbit with non-zero eccentricities, respectively. However, the successive orbital evolution of the two moons is not studied. Here, we perform direct $N$-body orbital integrations of the moons, including the Martian oblateness of the $J_2$ and $J_4$ terms. We show that the two moons, while they precess, likely collide within $\sim 10^4$ years with an impact velocity of $v_{\rm imp} \sim 100-300$ m s$^{-1}$ ($\sim 10-30$ times moons' escape velocity) and with an isotropic impact direction. The impact occurs around the apocenter and the pericenter of the inner and outer moons, respectively, where the timescale of this periodic orbital alignment is regulated by the precession. By performing additional impact simulations, we show that such a high-velocity impact likely results in a disruptive outcome, forming a debris ring at around the Martian synchronous orbit, from which several small moons would accrete. Such an evolutionary path would eventually form a different Martian moons system from the one we see today. Therefore, it seems unlikely that Phobos and Deimos are split directly from a single ancestor moon.

Even among the most irradiated gas giants, so-called ultra-hot Jupiters, KELT-9b stands out as the hottest planet thus far discovered with a dayside temperature of over 4500K. At these extreme irradiation levels, we expect an increase in heat redistribution efficiency and a low Bond albedo owed to an extended atmosphere with molecular hydrogen dissociation occurring on the planetary dayside. We present new photometric observations of the KELT-9 system throughout 4 full orbits and 9 separate occultations obtained by the 30cm space telescope CHEOPS. The CHEOPS bandpass, located at optical wavelengths, captures the peak of the thermal emission spectrum of KELT-9b. In this work we simultaneously analyse CHEOPS phase curves along with public phase curves from TESS and Spitzer to infer joint constraints on the phase curve variation, gravity-darkened transits, and occultation depth in three bandpasses, as well as derive 2D temperature maps of the atmosphere at three different depths. We find a day-night heat redistribution efficiency of $\sim$0.3 which confirms expectations of enhanced energy transfer to the planetary nightside due to dissociation and recombination of molecular hydrogen. We also calculate a Bond albedo consistent with zero. We find no evidence of variability of the brightness temperature of the planet, excluding variability greater than 1% (1$\sigma$).

We examine the computation of wide-angle corrections to the galaxy power spectrum including redshift-space distortions and relativistic Doppler corrections, and also including multiple tracers with differing clustering, magnification and evolution biases. We show that the inclusion of the relativistic Doppler contribution is crucial for a consistent wide-angle expansion for large-scale surveys, both in the single and multi-tracer cases. We also give for the first time the wide-angle cross-power spectrum associated with the Doppler magnification-galaxy cross correlation, which has been shown to be a new way to test general relativity. In the full-sky power spectrum, the wide-angle expansion allows integrals over products of spherical Bessel functions to be computed analytically as distributional functions, which are then relatively simple to integrate over. We give for the first time a complete discussion and new derivation of the finite part of the divergent integrals of the form $\int_0^\infty dr r^n j_\ell(kr) j_\ell'(qr)$, which are necessary to compute the wide-angle corrections when a general window function is included. This facilitates a novel method for integrating a general analytic function against a pair of spherical Bessel functions.

The understanding of the accretion process has a central role in the understanding of star and planet formation. We aim to test how accretion variability influences previous correlation analyses of the relation between X-ray activity and accretion rates, which is important for understanding the evolution of circumstellar disks and disk photoevaporation. We monitored accreting stars in the Orion Nebula Cluster from November 24, 2014, until February 17, 2019, for 42 epochs with the Wendelstein Wide Field Imager in the Sloan Digital Sky Survey u'g'r' filters on the 2 m Fraunhofer Telescope on Mount Wendelstein. Mass accretion rates were determined from the measured ultraviolet excess. The influence of the mass accretion rate variability on the relation between X-ray luminosities and mass accretion rates was analyzed statistically. We find a typical interquartile range of ~ 0.3 dex for the mass accretion rate variability on timescales from weeks to ~ 2 years. The variability has likely no significant influence on a correlation analysis of the X-ray luminosity and the mass accretion rate observed at different times when the sample size is large enough. The observed anticorrelation between the X-ray luminosity and the mass accretion rate predicted by models of photoevaporation-starved accretion is likely not due to a bias introduced by different observing times.

We present JWST/MIRI MRS spectroscopy of NGC7319, the largest galaxy in the Stephan's Quintet, observed as part of the Early Release Observations (ERO). NGC7319 hosts a type 2 active galactic nucleus (AGN) and a low-power radio jet (L_1.4GHz=3.3x10^22 W Hz^-1) with two asymmetric radio hotspots at 430 pc (N2) and 1.5 kpc (S2) projected distances from the unresolved radio core. The MRS data suggest that the molecular material in the disk of the galaxy decelerates the jet and causes this length asymmetry. We find enhanced emission from warm and hot H_2 (T_w=330+-40 K, T_h=900+-60 K) and ionized gas at the intersection between the jet axis and dust lanes in the disk. This emission is coincident with the radio hotspot N2 closest to the core, suggesting that the jet-interstellar medium (ISM) interaction decelerates the jet. Conversely, the mid-infrared emission at the more distant hotspot is fainter, more highly ionized, and with lower H_2 excitation, suggesting a more diffuse atomic environment where the jet can progress to farther distances. At the N2 radio hotspot, the ionized gas mass (M_ion=(2.4-12)x10^5 Msun) is comparable to that of the warm H_2, but the former is more turbulent (sigma_ion~300 vs. sigma_H2~150 km/s), so the mechanical energy of the ionized gas is ~1.3-10 times higher. From these estimates, we find that only <0.2% of the jet energy remains as mechanical energy in these two ISM phases at N2. We also find extended (r>0.3-1.5 kpc) high-ionization emission ([MgV], [NeVI], and [NeV]) close to the radio hotspots. This initial analysis of NGC7319 shows the potential of MIRI/MRS to investigate the AGN feedback mechanisms due to radio jets and their radiation field in the, often heavily dust-enshrouded, central regions of galaxies. Understanding these mechanisms is an essential ingredient in the development of cosmological simulations of galaxy evolution.

We present ALMA observations of CO $J = 2-1$ and CS $J = 5-4$ emission from the disk around TW~Hydrae. Both molecules trace a predominantly Keplerian velocity structure, although a slowing of the rotation velocity is detected at the outer edge of the disk beyond ${\approx}~140$~au in CO emission. This was attributed to the enhanced pressure support from the gas density taper near the outer edge of the disk. Subtraction of an azimuthally symmetric background velocity structure reveals localized deviations in the gas kinematics traced by each of the molecules. Both CO and CS exhibit a `Doppler flip' feature, centered nearly along the minor axis of the disk (${\rm PA} \sim 60\degr$) at a radius of $1\farcs35$, coinciding with the large gap observed in scattered light and mm~continuum. In addition, the CO emission, both through changes in intensity and its kinematics, traces a tightly wound spiral, previously seen with higher frequency CO $J = 3-2$ observations (Teague et al., 2019). Through comparison with linear models of the spiral wakes generated by embedded planets, we interpret these features in the context of interactions with a Saturn-mass planet within the gap at a position angle of ${\rm PA} = 60\degr$, consistent with the theoretical predictions of (Mentiplay et al. 2019). The lack of a corresponding spiral in the CS emission is attributed to the strong vertical dependence on the buoyancy spirals which are believed to only grow in the atmospheric of the disk, rather than those traced by CS emission.

In solar cycles 23-24, solar activity noticeably decreased, and, as a result, solar wind parameters decreased. Based on the measurements of the OMNI base for the period 1976-2019, the time profiles of the main solar wind parameters and magnetospheric indices for the main interplanetary drivers of magnetospheric disturbances (solar wind types CIR, Sheath, ejecta and MC) are studied using the double superposed epoch method. The main task of the research is to compare time profiles for the epoch of high solar activity at 21-22 solar cycles and the epoch of low activity at 23-24 solar cycles. The following results were obtained. (1) The analysis did not show a statistically significant change in driver durations during the epoch of minimum. (2) The time profiles of all parameters for all types of SW in the epoch of low activity have the same shape as in the epoch of high activity, but locate at lower values of the parameters. (3) In CIR events, the longitude angle of the solar wind flow has a characteristic S-shape, but in the epoch of low activity it varies in a larger range than in the previous epoch.

Stephan's Quintet (SQ, distance=85$\pm$6 Mpc) is unique among compact groups of galaxies. Observations have previously shown that interactions between multiple members, including a high-speed intruder galaxy currently colliding into the intragroup medium, have likely generated tidal debris in the form of multiple gaseous and stellar filaments, the formation of tidal dwarfs and intragroup-medium starbursts, as well as widespread intergalactic shocked gas. The details and timing of the interactions/collisions remain poorly understood because of the multiple nature. Here we report atomic hydrogen (HI) observations in the vicinity of SQ with a smoothed sensitivity of 1$\sigma$=4.2 $\times 10^{16}\rm cm^{-2}$ per channel ($\Delta$v=20 km s$^{-1}$; angular-resolution=4'), which are about two orders of magnitude deeper than previous observations. The data reveal a large HI structure (linear scale ~0.6 Mpc) encompassing an extended source of size ~0.4 Mpc associated with the debris field and a curved diffuse feature of length ~0.5 Mpc attached to the south edge of the extended source. The diffuse feature was likely produced by tidal interactions in early stages of SQ (>1 Gyr ago), though it is not clear how the low density HI gas (N$_{\rm HI}\leq 10^{18}\rm cm^{-2}$) can survive the ionization by the inter-galactic UV background on such a long time scale. Our observations require a rethinking of gas in outer parts of galaxy groups and demand complex modeling of different phases of the intragroup medium in simulations of group formation.

I review studies of core collapse supernovae (CCSNe) and similar transient events that attribute major roles to jets in powering most CCSNe and in shaping their ejecta. I start with reviewing the jittering jets explosion mechanism that I take to power most CCSN explosions. Neutrino heating does play a role in boosting the jets. I compare the morphologies of some CCSN remnants to planetary nebulae to conclude that jets and instabilities are behind the shaping of their ejecta. I then discuss CCSNe that are descendants of rapidly rotating collapsing cores that result in fixed-axis jets (with small jittering) that shape bipolar ejecta. A large fraction of the bipolar CCSNe are superluminous supernovae (SLSNe). I conclude that modelling of SLSNe lightcurves and bumps in the lightcurves must include jets, even when considering energetic magnetars and/or ejecta interaction with the circumstellar matter (CSM). I connect the properties of bipolar CCSNe to common envelope jets supernovae (CEJSNe) where an old neutron star or a black hole spirals-in inside the envelope and then inside the core of a red supergiant. I discuss how jets can shape the pre-explosion CSM, as in supernova 1987A, and can power pre-explosion outbursts (precursors) in binary systems progenitors of CCSNe and CEJSNe. Binary interaction facilitate also the launching of post-explosion jets.

To achieve its ambitious scientific goals, the Near-Infrared Spectrograph, NIRSpec, on board the Webb Space Telescope, needs to meet very demanding throughput requirements, here quantified in terms of photon-conversion efficiency (PCE). During the calibration activities performed for the instrument commissioning, we have obtained the first in-flight measurements of its PCE and also updated the modeling of the light losses occurring in the NIRSpec slit devices. The measured PCE of NIRSpec fixed-slit and multi-object spectroscopy modes overall meets or exceeds the pre-launch model predictions. The results are more contrasted for the integral-field spectroscopy mode, where the differences with the model can reach -20%, above 4 micron, and exceed +30%, below 2 micron. Additionally, thanks to the high quality of the JWST point-spread function, our slit-losses, at the shorter wavelength, are significantly decreased with respect to the pre-flight modeling. These results, combined with the confirmed low noise performance of the detectors, make of NIRSpec an exceptionally sensitive spectrograph.

We present a systematic study of X-ray cavities using archival Chandra observations of nearby galaxy clusters selected by their Sunyaev-Zel'dovich (SZ) signature in the Planck survey, which provides a nearly unbiased mass-selected sample to explore the entire AGN feedback duty cycle. Based on X-ray image analysis, we report that 30 of the 164 clusters show X-ray cavities, which corresponds to a detection fraction of 18%. After correcting for spatial resolution to match the high-$z$ SPT-SZ sample, the detection fraction decreases to 9%, consistent with the high-z sample, hinting that the AGN feedback has not evolved across almost 8 Gyrs. Our finding agrees with the lack of evolution of cool-core clusters fraction. We calculate the cavity power, P_{\rm cav}, and find that most systems of our sample have enough AGN heating to offset the radiative losses of the intracluster medium.

We present radio pulsar emission beam analyses and models with the primary intent of examining pulsar beam geometry and physics over the broadest band of radio frequencies reasonably obtainable. We consider a set of well-studied pulsars that lie within the Arecibo sky. These pulsars stand out for the broad frequency range over which emission is detectable, and have been extensively observed at frequencies up to 4.5 GHz and down to below 100 MHz. We utilize published profiles to quantify a more complete picture of the frequency evolution of these pulsars using the core/double-cone emission beam model as our classification framework. For the low-frequency observations, we take into account measured scattering time-scales to infer intrinsic vs scatter broadening of the pulse profile. Lastly, we discuss the populational trends of the core/conal class profiles with respect to intrinsic parameters. We demonstrate that for this sub-population of pulsars, core and conal dominated profiles cluster together into two roughly segregated $P$-$\dot{P}$ populations, lending credence to the proposal that an evolution in the pair-formation geometries is responsible for core/conal emission and other emission effects such as nulling and mode-changing.

Observations suggest that coherent radio emission from pulsars is excited in a dense pulsar plasma by curvature radiation from charge bunches. Numerous studies propose that these charge bunches are relativistic charge solitons which are solutions of the non-linear Schr\"{o}dinger equation (NLSE) with a group velocity dispersion ($G$), cubic-nonlinearity($q$) and non-linear Landau damping ($s$). The formation of stable solitons crucially depends on the parameters $G, q$ and $s$ and the particle distribution function. In this work, we use realistic pulsar plasma parameters obtained from observational constraints to explore the parameter space of NLSE for two representative distribution functions (DF) of particles' momenta: Lorentzian (long-tailed) and Gaussian (short-tailed). The choice of DF critically affects the value of $|s/q|$, which, in turn, determines whether solitons can form. Numerical simulations show that well-formed solitons are obtained only for small values of $|s/q| \lesssim 0.1$ while for moderate and higher values of $|s/q| \gtrsim 0.5$ soliton formation is suppressed. Small values for $|s/q| \sim 0.1$ are readily obtained for long-tailed DF for a wide range of plasma temperatures. On the other hand, short-tailed DF provides these values only for some narrow range of plasma parameters. Thus, the presence of a prominent high-energy tail in the particle DF favours soliton formation for a wide range of plasma parameters. Besides pair plasma, we also include an iron ion component and find that they make a negligible contribution in either modifying the NLSE coefficients or contributing to charge separation.

We study the effect of temperature on beta decay rate during primordial nucleosynthesis. Using thermal contributions to the renormalized mass of electron, we re-compute thermal effects to the nucleosynthesis parameters in the early universe in relation to the thermal self-mass of electron. In this study we show how the presence of fermions in a medium cause the variation in nucleosynthesis parameters with temperature. Before and after nucleosynthesis, temperature contribution from the electron self-mass goes away. The temperature dependence of beta decay rate, helium abundance and energy density of the universe are calculated as a function of temperature during nucleosynthesis. The values of these nucleosynthesis parameters before and after the nucleosynthesis are also calculated.

We have estimated masses of components of visual binaries from their spectral classification. We have selected pairs, where the less massive component looks more evolved. Spectral observations of some of such pairs were made, and at least one pair, HD~156331, was confirmed to have components of different age. Since mass exchange is excluded in wide binaries, it means that HD~156331 can be formed by the capture.

We present integral field spectroscopic observations of NGC 5972 obtained with the Multi Unit Spectroscopic Explorer (MUSE) at VLT. NGC 5972 is a nearby galaxy containing both an active galactic nucleus (AGN), and an extended emission line region (EELR) reaching out to $\sim 17$ kpc from the nucleus. We analyze the physical conditions of the EELR using spatially-resolved spectra, focusing on the radial dependence of ionization state together with the light travel time distance to probe the variability of the AGN on $\gtrsim 10^{4}$ yr timescales. The kinematic analysis suggests multiple components: (a) a faint component following the rotation of the large scale disk; (b) a component associated with the EELR suggestive of extraplanar gas connected to tidal tails; (c) a kinematically decoupled nuclear disk. Both the kinematics and the observed tidal tails suggest a major past interaction event. Emission line diagnostics along the EELR arms typically evidence Seyfert-like emission, implying that the EELR was primarily ionized by the AGN. We generate a set of photoionization models and fit these to different regions along the EELR. This allows us to estimate the bolometric luminosity required at different radii to excite the gas to the observed state. Our results suggests that NGC 5972 is a fading quasar, showing a steady gradual decrease in intrinsic AGN luminosity, and hence the accretion rate onto the SMBH, by a factor $\sim 100$ over the past $5 \times 10^{4}$ yr.

We study the rest-frame ultraviolet (UV) continuum slopes ($\beta$) of galaxies at redshifts $8 < z < 15$, using a combination of JWST ERO and ERS NIRcam imaging and ground-based near-infrared imaging of the COSMOS field. The combination of JWST and ground-based imaging provides a wide baseline in both redshift and absolute UV magnitude ($-22.5 < M_{\rm UV} < 18.5$), sufficient to allow a meaningful comparison to previous results at lower redshift. Using a power-law fitting technique, we find that our full sample (median $M_{\rm UV}=-19.5\pm 1.1$) returns an inverse-variance weighted mean value of $\langle \beta \rangle = -2.07 \pm 0.05$, with a corresponding median value of $\beta=-2.26\pm 0.12$. These values imply that the UV colours of galaxies at $z>8$ are, on average, no bluer than the bluest galaxies in the local Universe. Moreover, we find tentative evidence for a $\beta-M_{\rm UV}$ relation, such that brighter UV galaxies display somewhat redder UV slopes ($\rm{d}\beta/ \rm{d} M_{\rm UV} = -0.12 \pm 0.05$). Comparing to results at lower redshift, we find that the slope of our $\beta-M_{\rm UV}$ relation is fully consistent with that observed at $z\simeq 5$ and that, at a given $M_{\rm UV}$, our $8<z<15$ galaxies are somewhat bluer ($\delta \beta = -0.27 \pm 0.06$) than their $z\simeq 5$ counterparts. Finally, we do not find strong evidence that any objects in our sample display ultra-blue UV continuum slopes (i.e., $\beta\lesssim-3$) that would require their UV emission to be dominated by ultra-young, dust-free stellar populations with high Lyman-continuum escape fractions.

Sites for next-generation telescopes are chosen decades before the first light of a telescope. Site selection is usually based on recent measurements over a period that is too short to account for long-term changes in observing conditions such as those arising from anthropogenic climate change. In this study, we analyse trends in astronomical observing conditions for eight sites. Most sites either already host telescopes that provide in situ measurements of weather parameters or are candidates for hosting next-generation telescopes. For a fine representation of orography, we use the highest resolution global climate model (GCM) ensemble available provided by the high-resolution model intercomparison project and developed as part of the European Union Horizon 2020 PRIMAVERA project. We evaluate atmosphere-only and coupled PRIMAVERA GCM historical simulations against in situ measurements and the fifth generation atmospheric reanalysis (ERA5) of the ECMWF. The projections of changes in current site conditions are then analysed for the period 2015-2050 using PRIMAVERA future climate simulations. Over most sites, we find that PRIMAVERA GCMs show good agreement in temperature, specific humidity, and precipitable water vapour compared to in situ observations and ERA5. The ability of PRIMAVERA to simulate those variables increases confidence in their projections. For those variables, the model ensemble projects an increasing trend for all sites. On the other hand, no significant trends are projected for relative humidity, cloud cover, or astronomical seeing and PRIMAVERA does not simulate these variables well compared to observations and reanalyses. Therefore, there is little confidence in these projections. Our results show that climate change likely increases time lost due to bad site conditions.

According to the current paradigm of galaxy formation, the first galaxies have been likely formed within large dark matter haloes. The fragmentation of these massive haloes led to the formation of galaxy protoclusters, which are usually composed of one to a few bright objects, surrounded by numerous fainter (and less massive) galaxies. These early structures could have played a major role in reionising the neutral hydrogen within the first billion years of the Universe; especially, if their number density is significant. Taking advantage of the unprecedented sensitivity reached by the James Webb Space Telescope (JWST), galaxy protoclusters can now be identified and studied in increasing numbers beyond $z\geq\ $6. Characterising their contribution to the UV photon budget could supply new insights on the reionisation process. We analyse the first JWST dataset behind SMACS0723-7327 to search for protoclusters at $z\geq6$, combining the available spectroscopic and photometric data. We then compare our findings with semi-analytical models and simulations. In addition to two bright galaxies ($\leq$26.5 AB in F277W), separated by $\sim$11\arcsec and spectroscopically confirmed at $z_{spec}=7.66$, we identify 6 additional galaxies with similar colors in a $\theta\sim20$\arcsec radius around these (corresponding to R$\sim60-90$ kpc in the source plane). Using several methods, we estimate the mass of the dark matter halo of this protocluster, $\sim$4$\times$10$^{11}$M$_{\odot}$, consistent with various predictions. The physical properties of all protocluster members are also in excellent agreement with what has been previously found at lower redshifts: star-formation main sequence and protocluster size. This detection adds to just a few protoclusters currently known in the first billion years of the universe. Such $z \ge 7 $ galaxy protoclusters may play an important role in cosmic reionisation.

Aims: We characterised the properties of the bar hosted in lenticular galaxy NGC 4277, which is located behind the Virgo cluster. Methods: We measured the bar length and strength from the surface photometry obtained from the broad-band imaging of the Sloan Digital Sky Survey and we derived the bar pattern speed from the stellar kinematics obtained from the integral-field spectroscopy performed with the Multi Unit Spectroscopic Explorer at the Very Large Telescope. We also estimated the co-rotation radius from the circular velocity, which we constrained by correcting the stellar streaming motions for asymmetric drift, and we finally derived the bar rotation rate. Results: We found that NGC 4277 hosts a short ($R_{bar}=3.2^{+0.9}_{-0.6}$ kpc), weak ($S_{bar}=0.21 \pm 0.02$), and slow ($R=1.8^{+0.5}_ {-0.3}$) bar and its pattern speed ($\Omega_{bar}=24.7\pm3.4$ km s$^{-1}$ kpc$^{-1}$) is amongst the best-constrained ones ever obtained with the Tremaine-Weinberg (TW) method with relative statistical errors of $\sim0.2$. Conclusions: NGC 4277 is the first clear-cut case of a galaxy hosting a slow stellar bar ($R>1.4$ at more than a 1$\sigma$ confidence level) measured with the model-independent TW method. A possible interaction with the neighbour galaxy NGC 4273 could have triggered the formation of such a slow bar and/or the bar could be slowed down due to the dynamical friction with a significant amount of dark matter within the bar region.

The planned Laser Interferometric Space Antenna (LISA) will be able to detect gravitational waves (GWs) from intermediate mass binary black holes (IMBBHs) in the mass range $\sim 10^{2} \mbox{-} 10^{4} M_{\odot}$ up to a redshift $z\sim20$. Modulation effects due to LISA orbital motion around the Sun facilitate precise premerger localization of the sources, which in turn would help in electromagnetic (EM) follow-ups. In this work, we calculate the uncertainties in sky-position, luminosity distance, and time of coalescence as a function of time to coalescence. For representative masses of the IMBBHs, we synthesize a population of binaries uniformly located and oriented on a sphere of radius 3 Gpc and perform parameter estimation using the Fisher information matrix. We find that for systems with a total mass of $10^3 M_{\odot}$, the errors in the sky-position and luminosity distance are $\sim 0.4\,\text{deg}^2$ and $\sim 6\%$, respectively, 1 day prior to coalescence. The coalescence time can be predicted with an uncertainty $\lesssim 10$ sec, 1 day before coalescence. We also find that for $10^3M_{\odot}$, around $40\%$ ($100\%$) of the population has a source localization that is smaller than the field of view of Athena (LSST) 1 day before the merger. These extremely precise measurements can be used to alert ground-based GW detectors and EM telescopes about the time and location of these mergers. We also discuss mechanisms that may produce EM emission from IMBBH mergers and study its detectability using the planned Legacy Survey of Space and Time (LSST) in the optical and Athena in the X-ray bands. Detection of an EM transient may provide us vital clues about the environments where these mergers occur and the distance estimation can pave the way for cosmography.

The conversion of axionlike particles (ALPs) and photons in magnetised astrophysical environments provides a promising route to search for ALPs. The strongest limits to date on light ALPs use galaxy clusters as ALP--photon converters. However, such studies traditionally rely on simple models of the cluster magnetic fields, with the state-of-the-art being Gaussian random fields (GRFs). We present the first systematic study of ALP-photon conversion in more realistic, turbulent fields from dedicated magnetohydrodynamic (MHD) simulations, which we compare with GRF models. For GRFs, we analytically derive the distribution of conversion ratios at fixed energy and find that it follows an exponential law. We find that the MHD models agree with the exponential law for typical, small amplitude mixings but exhibit distinctly heavy tails for rare and large mixings. We explain how non-Gaussian, local spikes in the MHD magnetic field are mainly responsible for the heavy tail. Our results indicate that limits placed on ALPs using GRFs are conservative but that MHD models are necessary to reach the full potential of these searches.

We consider oscillons - localized, quasiperiodic, and extremely long-living classical solutions in models with real scalar fields. We develop their effective description in the limit of large size at finite field strength. Namely, we note that nonlinear long-range field configurations can be described by an effective complex field $\psi(t, \boldsymbol{x})$ which is related to the original fields by a canonical transformation. The action for $\psi$ has the form of a systematic gradient expansion. At every order of the expansion, such an effective theory has a global U(1) symmetry and hence a family of stationary nontopological solitons - oscillons. The decay of the latter objects is a nonperturbative process from the viewpoint of the effective theory. Our approach gives an intuitive understanding of oscillons in full nonlinearity and explains their longevity. Importantly, it also provides reliable selection criteria for models with long-lived oscillons. This technique is more precise in the nonrelativistic limit, in the notable cases of nonlinear, extremely long-lived, and large objects, and also in lower spatial dimensions. We test the effective theory by performing explicit numerical simulations of a $(d+1)$-dimensional scalar field with a plateau potential.

The number of events observed in neutrino telescopes depends on the neutrino fluxes in the Earth, their absorption while crossing the Earth and their interaction in the detector. In this paper, we investigate the impact of the QCD dynamics at high energies on the energy dependence of the average inelasticity and angular dependence of the absorption probability during the neutrino propagation through the Earth, as well in the determination of the properties of the incident astrophysical neutrino flux. Moreover, the number of events at the IceCube and IceCube - Gen2 are estimated considering different scenarios for the QCD dynamics and assuming the presence of a Super - Glashow flux, which peaks for energies above the Glashow resonance.

Some measurable characteristic timescales $\left\{t_\mathrm{trn}\right\}$ of transiting exoplanets are investigated in order to check preliminarily if their cumulative shifts over the years induced by the post-Newtonian (pN) gravitoelectric (Schwarzschild) and gravitomagnetic (Lense-Thirring) components of the stellar gravitational field are, at least in principle, measurable. Both the primary (planet in front of the star) and the secondary (planet behind the star) transits are considered along with their associated characteristic time intervals: the total transit duration $t_D$, the ingress/egress transit duration $\tau$, the full width at half maximum primary transit duration $t_H$, and also the time of conjunction $t_\mathrm{cj}$. For each of them, the net changes per orbit $\langle\Delta t_D\rangle,\,\langle\Delta\tau\rangle,\,\langle\Delta t_H\rangle,\,\langle\Delta t_\mathrm{cj}\rangle$ induced by the aforementioned pN accelerations are analytically obtained; also the Newtonian effect of the star's quadrupole mass moment $J_2^\star$ is worked out. They are calculated for a fictitious Sun-Jupiter system in an edge-on elliptical orbit, and the results are compared with the present-day experimental accuracies for the HD 286123 b exoplanet. Its pN gravitoelectric shift $\left\langle\Delta t_\mathrm{cj}^\mathrm{1pN}\right\rangle$ may become measurable, at least in principle, at a $\simeq 8\times 10^{-5}$ level of (formal) relative accuracy after about 30 years of continuous monitoring corresponding to about 1000 transits. Systematics like, e.g., confusing time standards, neglecting star spots, neglecting clouds, would likely deteriorate the actual accuracy. The method presented is general enough to be applied also to modified models of gravity.

Nuclear masses are predicted with the Bayesian neural networks by learning the mass surface of even-even nuclei and the correlation energies to their neighbouring nuclei. By keeping the known physics in various sophisticated mass models and performing the delicate design of neural networks, the proposed Bayesian machine learning (BML) mass model achieves an accuracy of $84$~keV, which crosses the accuracy threshold of the $100$~keV in the experimentally known region. It is also demonstrated the corresponding uncertainties of mass predictions are properly evaluated, while the uncertainties increase by about $50$~keV each step along the isotopic chains towards the unknown region. The shell structures in the known region are well described and several important features in the unknown region are predicted, such as the new magic numbers around $N = 40$, the robustness of $N = 82$ shell, the quenching of $N = 126$ shell, and the smooth separation energies around $N = 104$.