Papers for Tuesday, Jun 18 2024

In this paper we present the European Low Frequency Survey (ELFS), a project that will enable foregrounds-free measurements of the primordial $B$-mode polarization and a detection of the tensor-to-scalar ratio, $r$, to a level $\sigma(r) = 0.001$ by measuring the Galactic and extra-galactic emissions in the 5--120\,GHz frequency window. Indeed, the main difficulty in measuring the B-mode polarization comes from the fact that many other processes in the Universe also emit polarized microwaves, which obscure the faint Cosmic Microwave Background (CMB) signal. The first stage of this project is being carried out in synergy with the Simons Array (SA) collaboration, installing a 5.5--11\,GHz (X-band) coherent receiver at the focus of one of the three 3.5\,m SA telescopes in Atacama, Chile, followed by the installation of the QUIJOTE-MFI2 in the 10--20 GHz range. We designate this initial iteration of the ELFS program as ELFS-SA. The receivers are equipped with a fully digital back-end that will provide a frequency resolution of 1\,MHz across the band, allowing us to clean the scientific signal from unwanted radio frequency interference, particularly from low-Earth orbit satellite mega constellations. This paper reviews the scientific motivation for ELFS and its instrumental characteristics, and provides an update on the development of ELFS-SA.

JWST is revolutionizing our view of the early Universe by pushing the boundaries of detectable galaxies and black holes in redshift (upward) and mass (downward). The Little Red Dots (LRDs), detected by several surveys at $z > 4$, present a significant interpretational challenge, as their spectral energy distributions can mimic both AGN and stellar population templates. This study analyzes eight LRDs from the CEERS survey, utilizing NIRCam and MIRI photometry. By performing SED fitting across a vast parameter space, we explore a broad range of AGN fractions, defined as the ratio of the monochromatic luminosities (AGN, galaxy, and dust) at 0.53 $\mu m$ rest-frame. We find that the SEDs of all the LRDs investigated are consistent with having significant AGN contributions, with the best-fitting AGN fractions ranging between 40% and 85%. Moreover, assuming these LRDs do indeed host AGN, we can place limits on their black hole masses using the inferred AGN bolometric luminosities and adopting the Eddington limit. We find that, independent of the specific AGN fraction adopted, the LRDs' black holes are significantly overmassive relative to their host galaxies -- by $\sim 2$ dex, and up to $\sim 4$ dex in the most extreme cases -- compared to the local $M_{\bullet} - M_{\star}$ relation. The presence of overmassive black holes in the high-$z$ Universe may provide the strongest evidence yet of heavy black hole seeding occurring during the cosmic dark ages.

Strong gravitational lensing in galaxy clusters has become an essential tool in astrophysics, allowing us to directly probe the dark matter distribution and study magnified background sources. The precision and reliability of strong lensing models rely heavily on the number and quality of multiple images of background sources with spectroscopic redshifts. We present an updated strong lensing model of the galaxy cluster MACS J0416.1-2403 with the largest sample of multiple images with spectroscopic redshifts in a galaxy cluster field to date. Furthermore, we aim to demonstrate the effectiveness of JWST particularly its NIRISS camera, for strong lensing studies. We use the JWST 's NIRCam imaging and NIRSpec and NIRISS spectroscopy from the CAnadian NIRISS Unbiased Cluster Survey (CANUCS). The cluster mass model is constrained using Lenstool software. Our new dataset, used for constraining the lens model, comprises 303 secure multiple images from 111 background sources and includes systems with previously known MUSE redshift and systems for which we obtained spectroscopic redshift for the first time using NIRISS and NIRSpec spectroscopy. The total number of secure spectroscopic systems is >20% higher than in the previous strong lensing studies of this cluster. The derived strong lensing model can reproduce multiple images with the root-mean-square distance of 0.53''. We also provide a full catalogue with 415 multiple images, including less reliable candidates. We furthermore demonstrate the effectiveness of JWST particularly NIRISS, for strong lensing studies. As NIRISS F115W, F150W, and F200W grism spectroscopy captures at least two of the [OII] {\lambda}3727, [OIII] {\lambda}{\lambda}4959, 5007, and H{\alpha} lines at 1<z<3 (a redshift range particularly relevant for strong lensing studies) without target pre-selection, it complements MUSE and NIRSpec observations extremely well.

Context. Gas in protoplanetary disks mostly cools via thermal accommodation with dust particles. Thermal relaxation is thus highly sensitive to the local dust size distributions and the spatial distribution of the grains. So far, the interplay between thermal relaxation and gas turbulence has not been dynamically modeled in hydrodynamic simulations of protoplanetary disks with dust. Aims. We aim to study the effects of the vertical shear instability (VSI) on the thermal relaxation times, and vice versa. We are particularly interested in the influence of the initial dust grain size on the VSI and whether the emerging turbulence is sustained over long timescales. Results. We find that the emergence of the VSI is strongly dependent on the initial dust grain size. Coagulation also counteracts the emergence of hydrodynamic turbulence in our simulations, as shown by others before. Starting a simulation with larger grains (100 $\mu$m) generally leads to a less turbulent outcome. While the inner disk regions (within $\sim$ 70 au) develop turbulence in all three simulations, we find that the simulations with larger particles do not develop VSI in the outer disk. Conclusions. Our simulations with dynamically calculated thermal accommodation times based on the drifting and settling dust distribution show that the VSI, once developed in a disk, can be sustained over long timescales, even if grain growth is occurring. The VSI corrugates the dust layer and even diffuses the smaller grains into the upper atmosphere, where they can cool the gas. Whether the instability can emerge for a specific stratification depends on the initial dust grain sizes and the initial dust scale height. If the grains are initially $\gtrsim$ 100 $\mu$m and if the level of turbulence is initially assumed to be low, we find no VSI turbulence in the outer disk regions.

Simulations of galaxy formation are mostly unable to resolve the energy-conserving phase of individual supernova events, having to resort to subgrid models to distribute the energy and momentum resulting from stellar feedback. However, the properties of these simulated galaxies, including the morphology, stellar mass formed and the burstiness of the star formation history, are highly sensitive to numerical choices adopted in these subgrid models. Using the {\small SMUGGLE} stellar feedback model, we compute idealized simulations of a $M_{\rm vir} \sim 10^{10} \, \msun$ dwarf galaxy, a regime where most simulation codes predict significant burstiness in star formation, resulting in strong gas flows that lead to the formation of dark matter cores. We find that by varying only the directional distribution of momentum imparted from supernovae to the surrounding gas, while holding the total momentum per supernova constant, bursty star formation may be amplified or completely suppressed, and the total stellar mass formed can vary by as much as a factor of $\sim 3$. In particular, when momentum is primarily directed perpendicular to the gas disk, less bursty and lower overall star formation rates result, yielding less gas turbulence, more disky morphologies and a retention of cuspy dark matter density profiles. An improved understanding of the non-linear coupling of stellar feedback into inhomogeneous gaseous media is thus needed to make robust predictions for stellar morphologies and dark matter core formation in dwarfs independent of uncertain numerical choices in the baryonic treatment.

JWST has revealed a population of compact and extremely red galaxies at $z>4$, which likely host active galactic nuclei (AGN). We present a sample of 434 ``little red dots'' (LRDs), selected from the 0.54 deg$^2$ COSMOS-Web survey. We fit galaxy and AGN SED models to derive redshifts and physical properties; the sample spans $z\sim5$-$9$ after removing brown dwarf contaminants. We consider two extreme physical scenarios: either LRDs are all AGN, and their continuum emission is dominated by the accretion disk, or they are all compact star-forming galaxies, and their continuum is dominated by stars. If LRDs are AGN-dominated, our sample exhibits bolometric luminosities $\sim10^{45-47}$ erg\,s$^{-1}$, spanning the gap between JWST AGN in the literature and bright, rare quasars. We derive a bolometric luminosity function (LF) $\sim100$ times the (UV-selected) quasar LF, implying a non-evolving black hole accretion density of $\sim10^{-4}$ M$_\odot$ yr$^{-1}$ Mpc$^{-3}$ from $z\sim2$-$9$. By contrast, if LRDs are dominated by star formation, we derive stellar masses $\sim10^{8.5-10}\,M_\odot$. MIRI/F770W is key to deriving accurate stellar masses; without it, we derive a mass function inconsistent with $\Lambda$CDM. The median stellar mass profile is broadly consistent with the maximal stellar mass surface densities seen in the nearby universe, though the most massive $\sim50$\% of objects exceed this limit, requiring substantial AGN contribution to the continuum. Nevertheless, stacking all available X-ray, mid-IR, far-IR/sub-mm, and radio data yields non-detections. Whether dominated by dusty AGN, compact star-formation, or both, the high masses/luminosities and remarkable abundance of LRDs implies a dominant mode of early galaxy/SMBH growth.

We present a study of high-cadence, high-precision, optical light curves from the TESS satellite of 67 blazars in the southern sky. We provide descriptive flux statistics, power spectral density model parameters, and characteristic variability timescales. We find that only 15 BL Lacertae objects (BLLs) and 18 Flat Spectrum Radio Quasars (FSRQs) from the initial 26 and 41, respectively exhibit statistically-significant variability. We employ an adapted Power Spectral Response method to test the goodness of fit for the power spectral density function (PSD) to 3 power-law variant models. From our best-fitting description of the PSD, we extract the high-frequency power-spectral slopes and, if present, determine the significant bend or break in the model to identify characteristic timescales. We find no significant difference in the excess variance or rms-scatter between blazar subpopulations. We identify a linear rms-flux relation in ~69% of our sample, in which ~20% show a strong correlation. We find that both subpopulations of blazars show power spectral slope of $\alpha$~2 in which a broken power-law best fits 5 BLL & 6 FSRQ and a bending power-law best fits 1 BLL & 5 FSRQ. The shortest timescales of variability in each light curve range widely from minutes to weeks. Additionally, the objects' characteristic timescales range from ~0.8-8 days, consistent with the optical variability originating in the jet.

We present JWST NIRSpec observations in IFS mode of the galaxy GS5001 at redshift z=3.47, the brightest member of a candidate protocluster in the GOODS-S field. The data cover a field of view (FoV) of 4''$\times$4'' (~$30\times30$~kpc$^2$) and were obtained as part of the GA-NIFS GTO program. The observations include both high (R~2700) and low (R~100) spectral resolution data, spanning the rest-frame wavelength ranges 3700-6780A and 1300-11850A, respectively. We analyse the spatially resolved ionised gas kinematics and interstellar medium properties, including obscuration, gas metallicity, excitation, ionisation parameter, and electron density. In addition to the central galaxy, the NIRSpec FoV covers three components in the south, with velocities blue-shifted by -150 km/s with respect to the main galaxy, and another source in the north redshifted by ~200 km/s. The emission line ratios in the BPT diagram are consistent with star formation for all the sources in the FoV. We measure electron densities of ~500 cm$^{-3}$ in the different sources. The gas-phase metallicity in the main galaxy is 12+log(O/H) $= 8.45\pm0.04$, and slightly lower in the companions (12+log(O/H)$ = 8.34-8.42$), consistent with the mass-metallicity relation at $z\sim3$. We find peculiar line ratios (high log [NII]/H$\alpha$, low log [OIII]/H$\beta$) in the northern part of the main galaxy (GS5001). These could be attributed to either higher metallicity, or to shocks resulting from the interaction of the main galaxy with the northern source. We identify a spatially resolved outflow in the main galaxy, with an extension of about 3 kpc. We find maximum outflow velocities of ~400 km/s, an outflow mass of $(1.7\pm0.4)\times 10^8$ M$_{\odot}$, a mass outflow rate of $23\pm5$ M$_{\odot}$ yr$^{-1}$ and a mass loading factor of 0.23. These properties are compatible with star formation being the driver of the outflow.

We present a novel dataset that extends our view of the cosmic gas around z$\approx$3-4 Ly$\alpha$ emitting galaxies (LAEs) in the Muse Analysis of Gas around Galaxies (MAGG) survey by tracing a cool and enriched gas phase through 47 MgII absorbers identified in newly-obtained VLT/XSHOOTER near-infrared quasar spectra. Jointly with the more ionized gas traced by CIV systems and the neutral HI from previous work, we find that LAEs are distributed inside cosmic structures that contain multiphase gas in composition and temperature. All gas phases are a strong function of the large-scale galaxy environment: the MgII and the CIV strength and kinematics positively correlate with the number of associated galaxies, and it is $\approx$3-4 times more likely to detect metal absorbers around group than isolated LAEs. Exploring the redshift evolution, the covering factor of MgII around group and isolated LAEs remains approximately constant from z$\approx$3-4 to z<2, but the one of CIV around group galaxies drops by z<2. Adding the cool enriched gas traced by the MgII absorbers to the results we obtained for the HI and CIV gas, we put forward a picture in which LAEs lie along gas filaments that contain high column-density HI systems and are enriched by strong CIV and MgII absorbers. While the MgII gas appears to be more centrally concentrated near LAEs, weaker CIV systems trace instead a more diffuse gas phase extended up to larger distances around the galaxies.

Astronomical adaptive optics (AO) is a critical approach to enable ground-based diffraction-limited imaging and high contrast science, with the potential to enable habitable exoplanet imaging on future extremely large telescopes. However, AO systems must improve significantly to enable habitable exoplanet imaging. Time lag between the end of an exposure and end of deformable mirror commands being applied in an AO loop is now the dominant error term in many extreme AO systems (e.g., Poyneer et al. 2016), and within that lag component detector read time is becoming non-negligible (e.g., Cetre et al. 2018). This term will decrease as faster detector readout capabilities are developed by vendors. In complement, we have developed a modified Shack Hartmann Wavefront Sensor (SHWFS) to address this problem called the Focal-plane Actualized Shifted Technique Realized for a SHWFS (fastrSHWFS). The novelty of this design is to replace the usual lenslet array with a bespoke pupil-plane phase mask that redistributes the spot pattern on the detector into a rectangular array with a custom aspect ratio (in an extreme case, if the detector size can accommodate it, the array can be a single line). We present the fastrSHWFS concept and preliminary laboratory tests. For some detectors and AO systems, the fastrSHWFS technique can decrease the read time per frame compared to a regular SHWFS by up to 30x, supporting the goal of reduced AO lag needed to eventually enable habitable exoplanet imaging.

The detection of Dark Matter (DM) remains a significant challenge in particle physics. This study exploits advanced machine learning models to improve detection capabilities of liquid xenon time projection chamber experiments, utilizing state-of-the-art transformers alongside traditional methods like Multilayer Perceptrons and Convolutional Neural Networks. We evaluate various data representations and find that simplified feature representations, particularly corrected S1 and S2 signals, retain critical information for classification. Our results show that while transformers offer promising performance, simpler models like XGBoost can achieve comparable results with optimal data representations. We also derive exclusion limits in the cross-section versus DM mass parameter space, showing minimal differences between XGBoost and the best performing deep learning models. The comparative analysis of different machine learning approaches provides a valuable reference for future experiments by guiding the choice of models and data representations to maximize detection capabilities.

The kinematics of about 40 single stars belonging to the $\beta$ Pictoris moving group is studied. The age of the $\beta$ Pictoris moving group is estimated from these stars with ground-based line-of-sight velocity determinations by two methods. Both estimates are kinematic. In the first method we considered the traceback trajectories of the stars, giving an estimate of $t=13.2\pm1.4$ Myr. In the second method, by analyzing the instantaneous velocities of the stars, we show that there is an expansion of the stellar system occurring in the Galactic $xy$ plane. Based on this effect, we find the time interval elapsed from the beginning of the expansion of the $\beta$ Pictoris moving group to the present day, $t=20\pm2$ Myr.

We report the discovery of two new exoplanet systems around fully convective stars, found from the radial-velocity (RV) variations of their host stars measured with the nIR spectropolarimeter CFHT/SPIRou over multiple years. GJ 3378 b is a planet with minimum mass of $5.26^{+0.94}_{-0.97}$ Mearth in an eccentric 24.73-day orbit around an M4V star of 0.26 Msun. GJ 1289 b has a minimum mass of $6.27\pm1.25$ Mearth in a 111.74-day orbit, in a circular orbit around an M4.5V star of mass 0.21 Msun. Both stars are in the solar neighbourhood, at respectively 7.73 and 8.86 pc. The low-amplitude RV signals are detected after line-by-line post-processing treatment. These potential sub-Neptune class planets around cool stars may have temperate atmospheres and be interesting nearby systems for further studies. We also recovered the large-scale magnetic field of both stars, found to be mostly axisymmetric and dipolar, and with a polar strength of 20-30 G and 200-240 G for GJ 3378 (in 2019-21) and GJ 1289 (in 2022-23), respectively. The rotation periods measured with the magnetic field differ from the orbital periods, and in general, stellar activity is not seen in the studied nIR RV time series of both stars. GJ 3378 b detection is not confirmed by optical RVs and is therefore considered a candidate at this point.

We aim to investigate the global star formation scenario in star-forming sites AFGL 5157, [FSR2007] 0807 (hereafter FSR0807), [HKS2019] E70 (hereafter E70), [KPS2012] MWSC 0620 (hereafter KPS0620), and IRAS 05331+3115 in the outer galactic arm. The distribution of young stellar objects in these sites coincides with a higher extinction and H2 column density, which agrees with the notion that star formation occurs inside the dense molecular cloud cores. We have found two molecular structures at different velocities in this direction; one contains AFGL 5157 and FSR0807, and the other contains E70, [KPS2012] MWSC 0620, and IRAS 05331+3115. All these clusters in our target region are in different evolutionary stages and might form stars through different mechanisms. The E70 cluster seems to be the oldest in our sample; AFGL 5157 and FSR0807 formed later, and KPS0620 and IRAS 05331+3115 are the youngest sites. AFGL 5157 and FSR0807 are physically connected and have cold filamentary structures and dense hub regions. Additionally, the near-infrared photometric analysis shows signatures of massive star formation in these sites. KPS0620 also seems to have cold filamentary structures with the central hub but lacks signatures of massive stars. Our analysis suggests molecular gas flow and the hub filamentary star formation scenario in these regions. IRAS 05331+3115 is a single clump of molecular gas favoring low-mass star formation. Our study suggests that the selected area is a menagerie of star-forming sites where the formation of the stars happens through different processes.

We present the basic design of a large, light weight, spaceborne antenna for the Black Hole Explorer (BHEX) space Very Long Baseline Interferometry (space-VLBI) mission, achieving high efficiency operation at mm/sub-mm wavelengths. An introductory overview of the mission and its science background are provided. The BHEX mission targets fundamental black hole physics enabled by the detection of the finely structured image feature around black holes known as the photon ring, theoretically expected due to light orbiting the black hole before reaching the observer. Interferometer baselines much longer than an earth diameter are necessary to attain the spatial resolution required to detect the photon ring, leading to a space component. The science goals require high sensitivity observations at mm/sub-mm wavelengths, placing stringent constraints on antenna performance. The design approach described, seeks to balance the antenna aperture, volume and mass constraints of the NASA Explorers mission opportunity profile and the desired high performance. A 3.5 m aperture with a 40 $\mu$m surface rms is targeted. Currently, a symmetric, dual reflector, axially displaced ellipse (Gregorian ring focus) optical design and metallized carbon fiber reinforced plastic (CFRP) sandwich construction have been chosen to deliver high efficiency and light weight. Further exploration of design choices and parameter space and reflector shaping studies are in progress

We present an analysis of high-resolution optical spectra recorded for 30 stars of the split extended main-sequence turnoff (eMSTO) of the young ($\sim$ 40 Myr) Small Magellanic Cloud (SMC) globular cluster NGC 330. Spectra were obtained with the M2FS and MIKE spectrographs located on the Magellan-Clay 6.5m telescope. These spectra revealed the presence of Be stars, occupying primarily the cool side of the split main sequence (MS). Rotational velocity ($v\sin{i}$) measurements for most of the targets are consistent with the presence of two populations of stars in the cluster: one made up of rapidly rotating Be stars ($<v\sin{i}> \approx 200$ $\rm km\,s^{-1}$), and {the other} consisting of warmer stars with slower rotation ($<\!v\sin{i}\!>\approx50$ $\rm km\,s^{-1}$). Core emission in the H$\delta$ photospheric lines was observed for most of the H$\alpha$ emitters. The shell parameter computed for the targets in our sample indicate that most of the observed stars should have inclinations below 75$^{\circ}$. These results confirm the detection of Be stars obtained through photometry, but also reveal the presence of narrow H$\alpha$ and H$\delta$ features for some targets that cannot be detected with low-resolution spectroscopy or photometry. Asymmetry variability of H$\alpha$ line profiles on the timescales of a few years is also observed, and could provide information on the geometry of the decretion disks. Observations revealed the presence of nebular H$\alpha$ emission, strong enough in faint targets to compromise the extraction of spectra and to impact narrow band photometry used to assess the presence of H$\alpha$ emission.

Circularly polarized, nearly parallel propagating waves are prevalent in the solar wind at ion-kinetic scales. At these scales, the spectrum of turbulent fluctuations in the solar wind steepens, often called the transition-range, before flattening at sub-ion scales. Circularly polarized waves have been proposed as a mechanism to couple electromagnetic fluctuations to ion gyromotion, enabling ion-scale dissipation that results in observed ion-scale steepening. Here, we study Parker Solar Probe observations of an extended stream of fast solar wind ranging from 15-55 solar radii. We demonstrate that, throughout the stream, transition-range steepening at ion-scales is associated with the presence of significant left handed ion-kinetic scale waves, which are thought to be ion-cyclotron waves. We implement quasilinear theory to compute the rate at which ions are heated via cyclotron resonance with the observed circularly polarized waves given the empirically measured proton velocity distribution functions. We apply the Von Karman decay law to estimate the turbulent decay of the large-scale fluctuations, which is equal to the turbulent energy cascade rate. We find that the ion-cyclotron heating rates are correlated with, and amount to a significant fraction of, the turbulent energy cascade rate, implying that cyclotron heating is an important dissipation mechanism in the solar wind.

Magnetic reconnection is often considered as the primary particle acceleration mechanism in a magnetized blazar zone environment. The majority of radiation in the reconnection layer comes from plasmoids and their mergers. In particular, plasmoid mergers can produce strong multi-wavelength flares and major variations in synchrotron polarization signatures. However, radiative properties of plasmoid mergers have not been well explored due to difficulties in tracking the merging processes. Here we use an image processing method that combines the magnetic vector potential and density to identify isolated and merging plasmoids. We find that this method can clearly distinguish radiation contributions from isolated plasmoids, merging plasmoids, and the primary current sheet of reconnection. This new method enables us to study the radiative properties of plasmoids and mergers statistically. Our results show that isolated plasmoids have similar emissivity regardless of their sizes, and they generally have nonzero polarization degree (PD) due to their quasi-circular shape. Flares due to plasmoid mergers have relative amplitudes that are anti-proportional to the size ratio of the plasmoids participating in the mergers. Finally, only mergers between plasmoids of comparable sizes (width ratio $\lesssim 5$) can lead to significant spectral hardening and polarization angle (PA) variations; the amplitude of the PA variations is between 0 and $180^{\circ}$ and has a mean value of $90^{\circ}$. Our analyses on 2D simulations can pave the way for future analyses and machine learning techniques on radiative properties of 3D magnetic reconnection simulations.

The X-ray morphologies of clusters of galaxies display significant variations, reflecting their dynamical histories and the nonlinear dependence of X-ray emissivity on the density of the intracluster gas. Qualitative and quantitative assessments of X-ray morphology have long been considered a proxy for determining whether clusters are dynamically active or "relaxed." Conversely, the use of circularly or elliptically symmetric models for cluster emission can be complicated by the variety of complex features realized in nature, spanning scales from Mpc down to the resolution limit of current X-ray observatories. In this work, we use mock X-ray images from simulated clusters from THE THREE HUNDRED project to define a basis set of cluster image features. We take advantage of clusters' approximate self similarity to minimize the differences between images before encoding the remaining diversity through a distribution of high order polynomial coefficients. Principal component analysis then provides an orthogonal basis for this distribution, corresponding to natural perturbations from an average model. This representation allows novel, realistically complex X-ray cluster images to be easily generated, and we provide code to do so. The approach provides a simple way to generate training data for cluster image analysis algorithms, and could be straightforwardly adapted to generate clusters displaying specific types of features, or selected by physical characteristics available in the original simulations.

Approximate N-body methods, such as FastPM and COLA, have been successful in modelling halo and galaxy clustering statistics, but their low resolution on small scales is a limitation for applications that require high precision. Full N-body simulations can provide better accuracy but are too computationally expensive for a quick exploration of cosmological parameters. This paper presents a method for correcting distinct haloes identified in fast N-body simulations, so that various halo statistics improve to a percent level accuracy. The scheme seeks to find empirical corrections to halo properties such that the virial mass is the same as that of a corresponding halo in a full N-body simulation. The modified outer density contour of the corrected halo is determined on the basis of the FastPM settings and the number of particles inside the halo. This method only changes some parameters of the halo finder, and does not require any extra CPU-cost. We demonstrate that the adjusted halo catalogues of FastPM simulations significantly improve the precision of halo mass-based statistics from redshifts $z=0.0$ to $1.0$, and that our calibration can be applied to different cosmologies without needing to be recalibrated.

In our study, we examine a 2D radiation, relativistic, magnetohydrodynamics (Rad-RMHD) accretion flows around a spinning supermassive black hole. We begin by setting an initial equilibrium torus around the black hole, with an embedded initial magnetic field inside the torus. The strength of the initial magnetic field is determined by the plasma beta parameter, which is the ratio of the gas pressure to the magnetic pressure. In this paper, we perform a comparative study of the `magnetically arrested disc (MAD)' and `standard and normal evolution (SANE)' states. We observe that MAD state is possible for comparatively high initial magnetic field strength flow. Additionally, we also adopt a self-consistent two-temperature model to evaluate the luminosity and energy spectrum for our model. We observe that the total luminosity is mostly dominated by bremsstrahlung luminosity compared to the synchrotron luminosity due to the presence of highly dense torus. We also identify similar quasi-periodic oscillations (QPOs) for both MAD and SANE states based on power density spectrum analysis. Furthermore, our comparative study of the energy spectrum does not reveal any characteristic differences between MAD and SANE states. Lastly, we note that the MAD state is possible for both prograde and retrograde accretion flow.

A sample of warm low level semi-regular variables chosen from the General Catalogue of Variable Stars is studied for their chemical compositions by analysing high resolution optical spectra. The abundance ratios from Na/Fe to Eu/Fe displayed by these and previously analysed semi-regular variables are quite similar to ratios displayed by normal red giants across the Galactic thin and thick disks and halo populations in the solar neighbourhood suggesting from this perspective that the variables may be among the more photometrically active red giants.

We present a new step in our systematic effort to develop self-consistent dynamical models with a finite radial extent. The focus is on models with simple analytical density profiles allowing for analytical calculations of many dynamical properties. In this paper, we introduce a family of models, termed Wendland models, based on compactly supported radial basis functions. The family of models is characterised by a parameter $k$ that controls the smoothness of the transition at the truncation radius. In the limit $k\to\infty$, the Wendland model reduces to a non-truncated model with a Gaussian density profile. For each Wendland model, the density, mass and gravitational potential are simple truncated polynomial functions of radius. Via the SpheCow tool we demonstrate that all Wendland models can be supported by isotropic distribution functions. Surprisingly, the isotropic distribution function exhibits varied behaviour across different Wendland models. Additionally, each model can be supported by a continuum of Osipkov--Merritt orbital structures, ranging from radially anisotropic to completely tangential at the truncation radius. To the best of our knowledge, the Wendland models presented here are the first family of models accommodating both radial and tangential Osipkov--Merritt distribution functions. Using linear superposition, these models can easily be combined to generate Wendland models with even more diverse orbital structures. While the Wendland models are not fully representative of real dynamical systems due to their Gaussian-like density profile, this study lays important groundwork for constructing more realistic models with truncated density profiles that can be supported by a range of orbital structures.

We investigated the nature of the anomalies appearing in four microlensing events KMT-2020-BLG-0757, KMT-2022-BLG-0732, KMT-2022-BLG-1787, and KMT-2022-BLG-1852. The light curves of these events commonly exhibit initial bumps followed by subsequent troughs that extend across a substantial portion of the light curves. We performed thorough modeling of the anomalies to elucidate their characteristics. Despite their prolonged durations, which differ from the usual brief anomalies observed in typical planetary events, our analysis revealed that each anomaly in these events originated from a planetary companion located within the Einstein ring of the primary star. It was found that the initial bump arouse when the source star crossed one of the planetary caustics, while the subsequent trough feature occurred as the source traversed the region of minor image perturbations lying between the pair of planetary caustics. The estimated masses of the host and planet, their mass ratios, and the distance to the discovered planetary systems are $(M_{\rm host}/M_\odot, M_{\rm planet}/M_{\rm J}, q/10^{-3}, \dl/{\rm kpc}) = (0.58^{+0.33}_{-0.30}, 10.71^{+6.17}_{-5.61}, 17.61\pm 2.25,6.67^{+0.93}_{-1.30})$ for KMT-2020-BLG-0757, $(0.53^{+0.31}_{-0.31}, 1.12^{+0.65}_{-0.65}, 2.01 \pm 0.07, 6.66^{+1.19}_{-1.84})$ for KMT-2022-BLG-0732, $(0.42^{+0.32}_{-0.23}, 6.64^{+4.98}_{-3.64}, 15.07\pm 0.86, 7.55^{+0.89}_{-1.30})$ for KMT-2022-BLG-1787, and $(0.32^{+0.34}_{-0.19}, 4.98^{+5.42}_{-2.94}, 8.74\pm 0.49, 6.27^{+0.90}_{-1.15})$ for KMT-2022-BLG-1852. These parameters indicate that all the planets are giants with masses exceeding the mass of Jupiter in our solar system and the hosts are low-mass stars with masses substantially less massive than the Sun.

We perform broadband ($0.7-100$ keV) spectral analysis of five hard state observations of the low-mass back hole X-ray binary GX~339--4 taken by AstroSat during the rising phase of three outbursts from $2019$ to $2022$. We find that the outburst in 2021 was the only successful/full outburst, while the source was unable to make transition to the soft state during the other two outbursts in 2019 and 2022. Our spectral analysis employs two different model combinations, requiring two separate Comptonizing regions and their associated reflection components, and soft X-ray excess emission. The harder Comptonizing component dominates the overall bolometric luminosity, while the softer one remains relatively weak. Our spectral fits indicate that the disk evolves with the source luminosity, where the inner disk radius decreases with increasing luminosity. However, the disk remains substantially truncated throughout all the observations at the source luminosity of $\sim2-8\%\times$ of the Eddington luminosity. We note that our assumption of the soft X-ray excess emission as disk blackbody may not be realistic, and this kind of soft excess may arise due the non-homogeneity in the disk/corona geometry. Our temporal analysis deriving the power density spectra suggests that the break frequency increases with the source luminosity. Furthermore, our analysis demonstrates a consistency between the inner disk radii estimated from break frequency of the power density spectra and those obtained from the reflection modelling, supporting the truncated disk geometry in the hard state.

The recent detection of gamma-ray burst GRB~221009A has attracted attention due to its record brightness and first-ever detection of $\gtrsim 10$ TeV $\gamma$ rays from a GRB. Despite being the second-nearest GRB ever detected, at a redshift of $z=0.151$, the distance is large enough for severe attenuation of $\gamma$-ray flux at these energies due to $\gamma\gamma\to e^\pm$ pair production with the extragalactic background light (EBL). Here, we investigate whether the presence of cosmic voids along the line of sight can significantly impact the detectability of very-high energy (VHE, $>$ 100 GeV) gamma rays from distant sources. Notably, we find that the gamma-gamma opacity for VHE gamma rays can be reduced by approximately 10\% and up to 30\% at around 13 TeV, the highest-energy photon detected from GRB~221009A, for intervening cosmic voids along the line-of-sight with a combined radius of 110 Mpc, typically found from voids catalogs, and 250 Mpc, respectively. This reduction is substantially higher for TeV photons compared to GeV photons, attributable to the broader target photon spectrum that TeV photons interact with. This finding implies that VHE photons are more susceptible to variations in the EBL spectrum, especially in regions dominated by cosmic voids. Our study sheds light on the detection of $\gtrsim 10$ TeV gamma rays from GRB 221009A in particular, and on the detection of extragalactic VHE sources in general.

We report results from a detailed study of the neutron star X-ray binary, 4U 1608-52 using observations with {\it AstroSat} (LAXPC/SXT) and {\it NICER} during its 2016 and 2020 outbursts. The 0.7--20.0 keV spectra could be well described with the disk blackbody and thermal Comptonization model. The best-fitting inner disk temperature is $\sim$ 1 keV and radius { $\sim$ 22.17$^{+2.57}_{-2.38}$--27.19$^{+2.03}_{-1.85}$} km and no significant evolution was observed in the disk radius after performing flux and time-resolved spectroscopy. We used a multi-Lorentzian approach to fit the power density spectra and obtained broad-band noise variability. We estimated the energy-dependent fractional root mean square and time-lag of the broad-band noise, and these variations are quantitatively modelled as being due to the coherent variation of the disk emission and the coronal heating rate. Thus, the rapid temporal modeling is consistent with the longer term spectral evolution where the inner disk radius does not vary, and instead the variations can be attributed to accretion rate variations which changes the inner disk temperature and the coronal heating rate.

This study explores the Doppler shift at different wavelengths in the Interface Region Imaging Spectrograph (IRIS) solar spectrum and implements a comprehensive consideration of Doppler velocity oscillations in the IRIS channels. This comprehensive consideration reveals a propagating periodic perturbation in a large number of chromosphere and transition region (TR) bright points (BPs). To our knowledge, this is the first investigation of the longitudinal oscillations with damping in BPs using comprehensive consideration of the Doppler velocity at various wavelengths. The phenomena of attenuation in the red and blue Doppler shifts of the solar wavelength range were seen several times during the experiments. We utilized deep learning techniques to examine the statistical properties of damping in network and internetwork BPs, as well as active, quiet areas, and coronal hole areas. Our results revealed varying damping rates across different regions, with 80 percent of network BPs exhibiting damping in quiet areas and 72 in coronal hole areas. In active areas, the figure approached 33. For internetwork BPs, the values were 65, 54, and 63 percent for quiet areas, coronal hole areas, and active regions, respectively. The damping rate in active regions is twice as high at Internetwork's BPs. The damping components in this study were computed, and the findings show that the damping at all points is underdamped. The observed damping process suggests the propagation and leaking of energetic waves out of TR bright points, potentially contributing to the energy transport from the bright magnetic footpoints to the upper chromosphere, transition region, and corona.

We systemically evaluate the performance of the self-interacting dark matter (SIDM) halo model proposed in arXiv:2305.16176 with matched halos from high-resolution cosmological CDM and SIDM simulations. The model incorporates SIDM effects along mass evolution histories of CDM halos and it is applicable to both isolated halos and suhbhalos. We focus on the accuracy of the model in predicting halo density profiles at $z=0$ and the evolution of maximum circular velocity. We find the model predictions agree with the simulations within $10\%-50\%$ for most of the simulated (sub)halos, $50\%-100\%$ for extreme cases. This indicates that the model effectively captures the gravothermal evolution of the halos with very strong, velocity-dependent self-interactions. For an example application, we apply the model to study the impact of various SIDM scenarios on strong lensing perturber systems, demonstrating its utility in predicting SIDM effects for small-scale structure analyses. Our findings confirm that the model is an effective tool for mapping CDM halos into their SIDM counterparts.

We present the first on-sky results from an ultra-low-readout-noise Skipper CCD focal plane prototype for the SOAR Integral Field Spectrograph (SIFS). The Skipper CCD focal plane consists of four 6k x 1k, 15 $\mu$m pixel, fully-depleted, p-channel devices that have been thinned to ~250 $\mu$m, backside processed, and treated with an anti-reflective coating. These Skipper CCDs were configured for astronomical spectroscopy, i.e., single-sample readout noise < 4.3 e- rms/pixel, the ability to achieve multi-sample readout noise $\ll$ 1 e- rms/pixel, full-well capacities ~40,000-65,000 e-, low dark current and charge transfer inefficiency (~2 x 10$^{-4}$ e-/pixel/s and 3.44 x 10$^{-7}$, respectively), and an absolute quantum efficiency of $\gtrsim$ 80% between 450 nm and 980 nm ($\gtrsim$ 90% between 600 nm and 900 nm). We optimized the readout sequence timing to achieve sub-electron noise (~0.5 e- rms/pixel) in a region of 2k x 4k pixels and photon-counting noise (~0.22 e- rms/pixel) in a region of 220 x 4k pixels, each with a readout time of $\lesssim$ 17 min. We observed two quasars (HB89 1159+123 and QSO J1621-0042) at redshift z ~ 3.5, two high-redshift galaxy clusters (CL J1001+0220 and SPT-CL J2040-4451), an emission line galaxy at z = 0.3239, a candidate member star of the Boötes II ultra-faint dwarf galaxy, and five CALSPEC spectrophotometric standard stars (HD074000, HD60753, HD106252, HD101452, HD200654). We present charge-quantized, photon-counting observations of the quasar HB89 1159+123 and show the detector sensitivity increase for faint spectral features. We demonstrate signal-to-noise performance improvements for SIFS observations in the low-background, readout-noise-dominated regime. We outline scientific studies that will leverage the SIFS-Skipper CCD data and new detector architectures that utilize the Skipper floating gate amplifier with faster readout times.

The advancement of technology has led to rampant growth in data collection across almost every field, including astrophysics, with researchers turning to machine learning to process and analyze this data. One prominent example of this data in astrophysics is the atmospheric retrievals of exoplanets. In order to help bridge the gap between machine learning and astrophysics domain experts, the 2023 Ariel Data Challenge was hosted to predict posterior distributions of 7 exoplanetary features. The procedure outlined in this paper leveraged a combination of two deep learning models to address this challenge: a Multivariate Gaussian model that generates the mean and covariance matrix of a multivariate Gaussian distribution, and a Uniform Quantile model that predicts quantiles for use as the upper and lower bounds of a uniform distribution. Training of the Multivariate Gaussian model was found to be unstable, while training of the Uniform Quantile model was stable. An ensemble of uniform distributions was found to have competitive results during testing (posterior score of 696.43), and when combined with a multivariate Gaussian distribution achieved a final rank of third in the 2023 Ariel Data Challenge (final score of 681.57).

The JWST has been collecting scientific data for over two years now. Scientists are now looking deeper into the data, which introduces the need to correct known systematic effects. Important limiting factors for the MIRI/MRS are the pointing accuracy, non-linearity, detector charge migration, detector scattering, the accuracy of the PSF model, and the complex interplay between these. The Cycle 2 programme 3779 proposed a 72-point intra-pixel dither raster of the calibration star 10-Lac. In this first work of the paper series, we aim to address the degeneracy between the non-linearity and BFE that affect the pixel voltage integration ramps of the MRS. Due to the low flux in the longer wavelengths, we only do this in the 4.9 to 11.7 micron region. We fitted the ramps per pixel and dither, in order to fold in the deviations from classical non-linearity that are caused by charge migration. The ramp shapes should be repeatable depending on the part of the PSF that is sampled. By doing so, we defined both a grid-based linearity correction, and an interpolated linearity correction. We find significant improvements compared to the uniform illumination assumption. The standard deviation on the pixel ramp residual non-linearity is between 70-90% smaller than the current standard pipeline when self-calibrating with the grid. We are able to interpolate these coefficients to apply to any unresolved source not on the grid points, resulting in an up to 70% smaller standard deviation on the residual deviation from linearity. The FWHM is up to 20% narrower. The depth of the fringes is now consistent up the ramp. Pointing-specific linearity corrections allow us to fix the systematic deviation in the slopes. We demonstrated this for unresolved sources. The discovered trends with PSF sampling suggest that, we may be able to model ramps for spatially extended and resolved illumination as well.

The Tully-Fisher Relation (TFR) is a well-known empirical relationship between the luminosity of a spiral galaxy and its circular velocity, allowing us to estimate redshift independent distances. Here we use high signal-to-noise HI 21-cm integrated spectra from the second pilot data release (PDR2, 180 deg2) of the Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY). In order to prepare for the full WALLABY survey, we have investigated the TFR in phase 2 of the pilot survey with a further three fields. The data were obtained with wide-field Phased Array Feeds on the Australian Square Kilometre Array Pathfinder (ASKAP) and have an angular resolution of 30 arcsec and a velocity resolution of ~4 km/s. Galaxy luminosities have been measured from the Wide-field Infrared Survey Explorer (WISE), and optical galaxy inclinations from the Dark Energy Camera Legacy Survey. We present TFRs for wavelengths from 0.8-3.4{\mu}m. We examine sources of galaxy inclination data and investigate magnitudes from the DECam Local Volume Exploration Survey (DELVE) and DENIS catalogues and the 4HS target catalogue based on the VISTA Hemisphere Survey (VHS). We consider the baryonic TFR. These are all of interest for TFR using the full WALLABY survey of 200,000 galaxies. We demonstrate that WALLABY TFR distances can take their place among state of the art studies of the local velocity field.

The formation of protostars and their disks has been understood as the result of the gravitational collapse phase of an accumulation of dense gas that determines the mass reservoir of the star-disk system. Against this background, the broadly applied scenario of considering the formation of disks has been to model the collapse of a dense core assuming spherical spherical symmetry. Our understanding of the formation of star-disk systems is currently undergoing a reformation though. The picture evolves from interpreting disks as the sole outcome of the collapse of an isolated prestellar core to a more dynamic picture where disks are affected by the molecular cloud environment in which they form. In this review, we provide a status report of the state-of-the-art of spherical collapse models that are highly advanced in terms of the incorporated physics together with constraints from models that account for the possibility of infall onto star-disk systems in simplified test setups, as well as in multi-scale simulations that cover a dynamical range from the Giant Molecular Cloud environment down to the disk. Considering the observational constraints that favor a more dynamical picture of star formation, we finally discuss the challenges and prospects in linking the efforts of tackle the problem of star-disk formation in combined multi-scale, multi-physics simulations.

The accretion disks of supermassive black holes (SMBHs) harboring in active galactic nuclei (AGN) are considered to be an ideal site for producing different types of gamma-ray bursts (GRBs). The detectability of these GRB phenomena hidden in AGN disks is highly dependent on the dynamical evolution of the GRB relativistic jets. By investigating the reverse and forward shock dynamics due to the interaction between the jets and AGN disk material, we find that the relativistic jets can successfully break out from the disks only for a sufficiently high luminosity and a long enough duration. In comparison, relatively normal GRB jets are inclined to be choked in the disks, unless the GRBs occur near an SMBH with relatively low mass (e.g., $\sim 10^6M_{\odot}$). For the choked jets, unlike normal GRB prompt and afterglow emission, we can only expect to detect emission from the forward shock when the shock is very close to the edge of the disks, i.e., the shock breakout emission and subsequent cooling of the shock.

The Simons Observatory (SO) is a next-generation ground-based telescope located in the Atacama Desert in Chile, designed to map the cosmic microwave background (CMB) with unprecedented precision. The observatory consists of three small aperture telescopes (SATs) and one large aperture telescope (LAT), each optimized for distinct but complementary scientific goals. To achieve these goals, optimized scan strategies have been defined for both the SATs and LAT. This paper describes a software system deployed in SO that effectively translates high-level scan strategies into realistic observing scripts executable by the telescope, taking into account realistic observational constraints. The data volume of SO also necessitates a scalable software infrastructure to support its daily data processing needs. This paper also outlines an automated workflow system for managing data packaging and daily data reduction at the site.

We search for a redshift dependence of $\sigma_8^0$ using 23 growth rate measurements from redshift space distortions and peculiar velocity measurements as a consistency check of $\Lambda$CDM. For this purpose we use the dataset from arXiv:1806.10822 consisting of 22 measurements, which has been vetted for internal consistencies. Eighteen of these measurements have been obtained from the Gold-2017 sample, collated from multiple redshift space distortion surveys between 2009 and 2016, whereas the remaining four have been obtained from the eBOSS DR14 quasar survey. We also added one additional data point from the BOSS DR12 CMASS galaxy sample. We find that for this dataset the $\sigma_8^0$ values are consistent between the low redshift and high redshift samples using three different redshift cuts. This implies that the growth rate measurements are consistent with a constant $\sigma_8^0$ in accord with $\Lambda$CDM, assuming there are no uncontrolled systematics in this dataset.

The unified models of astrophysical sources to account for ultrahigh-energy cosmic rays (UHECRs) and high-energy cosmic neutrinos with energies greater than 100 TeV have been discussed. Based on model-independent arguments, we argue that if the photomeson production is the dominant mechanism, the most probable candidate sources are x-ray transient objects, allowing for the semi-transparency for the photomeson production. We develop a generic model of high-energy neutrino emitters accompanied by x-ray emission, and present how multimessenger observations can place significant constraints on the source parameters that characterize the common sources of neutrinos and UHECRs, such as the cosmic-ray loading factor. The requirements of UHECR acceleration, escape, and energetics further constrain the magnetic field and the bulk Lorentz factor of the sources. The resulting bounds provide diagnoses of the unified models, which demonstrates the importance of current and future x-ray facilities such as MAXI and Einstein Probe.

We present our new model for the description of the very high energy Galactic gamma-ray emission based on a discrete injection of cosmic rays by individual sources. We investigate the morphology of the very high energy gamma-ray sky, the detectability of cosmic-ray sources and the clumpiness of the diffuse gamma-ray flux, assuming two different scenarios for cosmic-ray propagation. Namely, a standard isotropic and homogeneous diffusion process and an isotropic and inhomogeneous diffusion process. We notably formulate a possible explanation to the small number of hadronic PeVatrons recently detected by LHAASO. In the case of the inhomogeneous diffusion process, we constrain the number of hadronic PeVatrons to be small. Finally, we give an argument that may explain the discrepancy between the interstellar gas density distribution and the very high energy diffuse gamma-ray flux.

A new observatory site should be investigated for its local climate conditions to see its potential and limitations. In this respect, we examine several meteorological parameters at the site of Timau National Observatory, Indonesia using the ERA5 dataset from 2002 to 2021. Based on this dataset, we conclude that the surface temperature at Timau is around 18.9 C with a relatively small temperature variation (1.5 C) over the day. This temperature stability is expected to give advantages to the observatory. In terms of humidity and water vapour, Timau is poor for infrared observations as the median precipitable water vapour exceeds 18 mm, even during the dry season. However, near-infrared observations are feasible. Even though our cloud cover analysis confirms the span of the observing season in the region, we find a significant discrepancy between the clear sky fraction derived from the ERA5 dataset and the one estimated using satellite imagery. Aside from the indicated bias, our results provide insights and directions for the operation and future development of the observatory.

Fast radio bursts (FRBs) are micro-to-millisecond duration radio transients that originate mostly from extragalactic distances. The emission mechanism responsible for these high luminosity, short duration transients remains debated. The models are broadly grouped into two classes: physical processes that occur within close proximity to a central engine; and central engines that release energy which moves to large radial distances and subsequently interacts with surrounding media producing radio waves. The expected emission region sizes are notably different between these two types of models. FRB emission size constraints can therefore be used to distinguish between these competing models and inform on the physics responsible. Here we present the measurement of two mutually coherent scintillation scales in the frequency spectrum of FRB 20221022A: one originating from a scattering screen located within the Milky Way, and the second originating from a scattering screen located within its host galaxy or local environment. We use the scattering media as an astrophysical lens to constrain the size of the lateral emission region, $R_{\star\mathrm{obs}} \lesssim 3\times10^{4}$ km. We find that this is inconsistent with the expected emission sizes for the large radial distance models, and is more naturally explained with an emission process that operates within or just beyond the magnetosphere of a central compact object. Recently, FRB 20221022A was found to exhibit an S-shaped polarisation angle swing, supporting a magnetospheric emission process. The scintillation results presented in this work independently support this conclusion, while highlighting scintillation as a useful tool in our understanding of FRB emission physics and progenitors.

We present the comprehensive analysis of the high-amplitude $\delta$ Sct star V2367 Cygni. Firstly, we perform the frequency analysis for the whole available set of the {\it Kepler} and {\it TESS} photometry. Most of the frequency peaks are harmonics or combinations of the three known independent frequencies with the highest amplitudes, i.e., $\nu_1=5.66106$\,d$^{-1}$, $\nu_2=7.14898$\,d$^{-1}$ and $\nu_3=7.77557$\,d$^{-1}$. The total number of independent frequencies is 26 and 25 from the {\it Kepler} and {\it TESS} light curve, respectively. Then, using the $UBVRI$ time-series photometry, we unambiguously identify the dominant frequency $\nu_1$ as the radial mode, whereas in the case of frequencies $\nu_2$ and $\nu_3$ the most probable mode degrees are $\ell=0$ or $\ell=2$. However, only the frequency $\nu_2$ can be associated with a radial mode, and only if higher order effects of rotation are taken into account. Including the rotational mode coupling, we constructed complex seismic models of V2367\,Cyg, which fit $\nu_1$ and $\nu_2$ as radial modes, and reproduce the amplitude of bolometric flux variations (the parameter $f$) for the dominant mode. The empirical values of $f$ are derived from the $UBVRI$ amplitudes and phases. We rely on the Bayesian analysis based on Monte Carlo simulations to derive constraints on evolutionary stage, mass, rotation, overshooting from the convective core and efficiency of convective transport in the envelope. Our seismic analysis clearly indicates that V2367\,Cyg is in a post-MS phase of evolution. This is the first extensive seismic modelling that takes into account the effect of rotational coupling between pulsation modes.

Stellar models indicate that the core compactness of a star, which is a common proxy for its explodability in a supernova, does not increase monotonically with the star's mass. Rather, the core compactness dips sharply over a range of carbon-oxygen core masses; this range may be somewhat sensitive to the star's metallicity and evolutionary history. Stars in this compactness dip are expected to experience supernovae leaving behind neutron stars, whereas stars on either side of this range are expected to form black holes. This results in a hypothetical mass range in which black holes should seldom form. Quantitatively, when applied to binary stripped stars, these models predict a dearth of binary black holes with component masses $\approx 10 M_\odot - 15 M_\odot$. The population of gravitational-wave signals indicates weak evidence for a dip in the distribution of chirp masses of merging binary black holes near $\approx 10 M_\odot - 12 M_\odot$. This feature could be linked to the hypothetical component mass gap described above, but this interpretation depends on what assumptions are made of the binaries' mass ratios. Here, we directly probe the distribution of binary black hole component masses to look for evidence of a gap. We find no evidence for this feature using data from the third gravitational-wave transient catalogue (GWTC-3). If this gap does exist in nature, we find that it is unlikely to be resolvable by the end of the current (fourth) LIGO-Virgo-KAGRA (LVK) observing run.

The inconsistency between experiments in the measurements of the local Universe expansion rate, the Hubble constant, suggests unknown systematics in the existing experiments or new physics. Gravitational-wave standard sirens, a method to independently provide direct measurements of the Hubble constant, have the potential to address this tension. Before that, it is critical to ensure there is no substantial systematics in the standard siren method. A significant systematic has been identified when the viewing angle of the gravitational-wave sources, the compact binary coalescences, is inferred inaccurately from electromagnetic observations of the sources. Such systematic has led to more than 10% discrepancy in the standard siren Hubble constant measurements with the observations of binary neutron star merger, GW170817. In this Letter, we develop a new formalism to infer and mitigate this systematic. We demonstrate that the systematic uncertainty of the Hubble constant measurements can be reduced to smaller than their statistical uncertainty with 5, 10, and 20 binary neutron star merger observations. We show that our formalism successfully reduces the systematics even if the shape of the biased viewing angle distribution does not follow precisely the model we choose. Our formalism ensures unbiased standard siren Hubble constant measurements when the binary viewing angles are inferred from electromagnetic observations.

This study examines the limitations of H$\alpha$ luminosity as a tracer of star formation rates (SFR) in spatially resolved observations. We carry out high-resolution simulations of a Milky Way-like galaxy including both supernova and photoionization feedback, and from these we generate synthetic H$\alpha$ emission maps that we compare to maps of the true distribution of young stellar objects (YSOs) on scales from whole-galaxy to individual molecular clouds ($\lesssim 100$ pc). Our results reveal significant spatial mismatches between H$\alpha$ and true YSO maps on sub-100 pc scales, primarily due to ionizing photon leakage, with a secondary contribution from young stars drifting away from their parent molecular clouds. On small scales these effect contribute significantly to the observed anti-correlation between gas and star formation, such that there is noticeably less anti-correlation if we replace an H$\alpha$-based star formation map with a YSO-based one; this in turn implies that previous studies have underestimated the time it takes for young stars to disperse their parent molecular clouds. However, these effects are limited in dense regions with hydrogen columns $N_\mathrm{H} > 3 \times 10^{21}$ cm$^{-2}$, where the H$\alpha$- and YSO-based SFR maps show better agreement. Based on this finding we propose a calibration model that can precisely measure the SFR of large molecular clouds (mean radius > 100 pc) with a combination of H$\alpha$ and CO observations, which provides a foundation for future study of star formation processes in extragalactic molecular clouds.

We present a numerical evidence supporting the primordial origin of secondary halo bias even on the galactic mass scale. Analyzing the data from the IllustrisTNG 300-1 simulations, we investigate the dependence of halo bias on the degree of misalignment between the protohalo inertia and initial tidal tensors, $\tau$, measured at redshift, $z_{i}=127$. From the TNG 300-1 galactic halos in logarithmic mass range of $10.5< m\equiv \log[M/(h^{-1}M_{\odot})]\le 13$ identified at $z=0,\ 0.5$ and $1$, a clear signal of $\tau$ bias is detected. For the case that $\tau$ is measured from the initial tidal field smoothed on the scale of $R_{f}/(h^{-1}\,{\rm Mpc})\lesssim 1$, the halo $\tau$ bias is found to be very similar in its tendency and amplitude to the spin bias at all of the three redshifts, if the effects of backsplash halos are properly eliminated. For the case of $R_{f}/(h^{-1}\,{\rm Mpc})=2$, the $\tau$ bias at $z=1$ turns out to behave like the age bias, diminishing rapidly in the range of $m> 12$. At $z=0$ and $0.5$, however, the $\tau$ and age bias factors show large differences in their overall strengths, which is attributed to the dominant nonlinear effects that undermine the former but enhance the latter. Given these numerical results along with the previous finding that $\tau$ shares a large amount of mutual information with the formation epochs and spin parameters of galactic halos, it is concluded that the origins of halo age and spin bias must be closely linked with the primordial factor, $\tau$, and that the difference in the tendency between the two bias factors on the galactic mass scale reflects the multi-scale influence of $\tau$ on the halo secondary properties.

We present results on the Paschen-$\alpha$ (Pa$\alpha$) emitting galaxies observed as part of the JWST FRESCO survey in the GOODS-North and GOODS-South fields. Utilizing the JWST NIRCam wide field slitless spectroscopy (WFSS), we analyze emission line fluxes, star formation rates (SFRs), and spatially resolved flux distributions of 97 Pa$\alpha$ emitters at $1<z<1.6$. To assess dust extinction within our sample, we combine Pa$\alpha$ fluxes with archival H$\alpha$ data taken with the Hubble Space Telescope (HST) WFC3 G141 grism. Our analysis reveals a significant correlation between dust extinction and galaxy stellar mass, where more massive galaxies exhibit greater dust extinction. We employ two-dimensional Pa$\alpha$ and F444W mapping to trace the distributions of star formation and stellar mass, respectively. Our observations indicate that lower mass galaxies are almost dust free in Pa$\alpha$ and exhibit smaller sizes both in star formation and underlying stellar continuum. In contrast, galaxies with a stellar mass greater than $10^{9.5}M_\odot$ display diverse dust extinction and star formation patterns. This variation suggests that the structures and properties of massive galaxies evolve through different phases, which involve, e.g., star formation in massive clumps, compaction, and inside-out quenching. This study demonstrates the capabilities of JWST WFSS in conducting systematic investigations of emission line galaxies and highlights the pivotal role of Pa$\alpha$ in advancing our understanding of dust extinction and obscured star formation in the early universe.

We report here our comparative analysis of active galactic nucleus (AGN) and star formation (SF) characteristics of a sample of narrow-line Seyfert 1 (NLS1) and broad-line Seyfert 1 (BLS1) galaxies. Our sample consisted of 373 BLS1 and 240 NLS1 galaxies spanning the redshift 0.02 to 0.8. The broad-band spectral energy distribution, constructed using data from the ultra-violet to the far-infrared, was modelled using CIGALE to derive the basic properties of our sample. We searched for differences in stellar mass, star formation rate (SFR), and AGN luminosity in the two populations. We also estimated new radiation-pressure corrected black hole masses for our sample of BLS1 and NLS1 galaxies. While the virial black hole mass (MBH) of BLS1 galaxies is similar to their radiation-pressure corrected MBH values, the virial MBH values of NLS1 galaxies are underestimated. We found that NLS1 galaxies have a lower MBH of log (MBH) = 7.45 +/- 0.27 and a higher log (Eddington ratio) of -0.72 +/- 0.22 than BLS1 galaxies, which have log (MBH) and log (Eddington ratio) of 8.04 +/- 0.26 and -1.08 +/- 0.24, respectively. The distributions of stellar mass, SFR, and specific star formation (sSFR = SFR/stellar mass) for the two populations are indistinguishable. This analysis is based on an independent approach and contradicts reports in the literature that NLS1 galaxies have a higher SF than BLS1 galaxies. While we found that AGN luminosity increases with stellar mass, luminosity of SF flattens at high stellar mass for both BLS1 and NLS1 galaxies. The reason may be that SF is suppressed by AGN feedback at stellar mass higher than 10^11 solar mass or that the AGN fuelling mechanism is decoupled from SF. Separating the sample into radio-detected and radio-undetected subsamples, we found no difference in their SF properties suggesting that the effect of AGN jets on SF is negligible.

The combination of the H I Ly{\alpha} (121.6 nm) line formation mechanism with ultraviolet (UV) Ly{\alpha} and white-light (WL) observations provides an effective method for determining the electron temperature of coronal mass ejections (CMEs). A key to ensuring the accuracy of this diagnostic technique is the precise calculation of theoretical Ly{\alpha} intensities. This study performs a modelled CME and its driven shock via the 3D MHD simulation. We generate synthetic UV and WL images of the CME and shock to quantify the impact of different assumptions on theoretical Ly{\alpha} intensities, such as the incident intensity of the Ly{\alpha} line (Idisk), the geometric scattering function (p({\theta})), and the kinetic temperature (Tn) assumed to be equal to the proton (Tp) or electron (Te) temperatures. By comparing differences of the Ly{\alpha} intensities under these assumptions, we find that: (1) Using the uniform or Carrington maps of the disk Ly{\alpha} emission underestimates the corona Ly{\alpha} intensity (< 10%) compared to the synchronic map, except for a slight overestimate (< 4%) in the partial CME core. The Carrington map yields lower uncertainties than the uniform disk. (2) The geometric scattering process has a minor impact on the Ly{\alpha} intensity, with a maximum relative uncertainty of < 5%. The Ly{\alpha} intensity is underestimated for the most part but overestimated in the CME core. (3) Compared to the assumption Tn = Tp, using Tn = Te leads to more complex relative uncertainties in CME Ly{\alpha} intensity. The CME core and void are both overestimated, with the maximum uncertainty in the core exceeding 50% and the void remaining below 35%. In the CME front, both over- and under-estimates exist with relative uncertainties of < 35%. The electron temperature assumption has a smaller impact on the shock, with an underestimated relative uncertainty of less than 20%.

Solar flares are powerful particle accelerators, and in the accepted standard flare model most of the flare energy is transported from a coronal energy-release region by accelerated electrons which stop collisionally in the chromosphere, heating and ionising the plasma, producing a broadband enhancement to the solar radiative output. We present a time-delay analysis of the infrared emission from two chromospheric sources in the flare SOL2014-09-24T17:50 taken at the McMath-Pierce telescope. By cross-correlating the intensity signals, measured with 1s cadence, from the two spatially resolved infrared sources we find a delay of 0.75 $\pm$ 0.07 s at 8.2 $\mu$m, where the uncertainties are quantified by a Monte Carlo analysis. The sources correlate well in brightness but have a time lag larger than can be reasonably explained by the energy transport dominated by non-thermal electrons precipitating from a single acceleration site in the corona. If interpreted as a time-of-flight difference between electrons traveling to each footpoint, we estimate time delays between 0.14 s and 0.42 s, for a reconnection site at the interior quasi-separatrix layer or at the null-point of the spine-fan topology inferred for this event. We employed modelling of electron transport via time-dependent Fokker-Planck and radiative hydrodynamic simulations to evaluate other possible sources of time-delay in the generation of the IR emission, such as differing ionisation timescales under different chromospheric conditions. Our results demonstrate that they are also unable to account for this discrepancy. This flare appears to require energy transport by some means other than electron beams originating in the corona.

A new model atom of nitrogen was developed using the energy levels of N I from laboratory measurements and also predicted in atomic structure calculations and the most up-to-date atomic data for computing radiative and collisional rates of the transitions. Solar abundance $\log\varepsilon_{\odot,N}$(1D NLTE) = 7.92$\pm$0.03 was determined from lines of N I by applying the synthetic spectrum method with the plane-parallel (1D) MARCS model atmosphere and taking into account the departures from local thermodynamic equilibrium (non-LTE = NLTE effects). Having implemented the 3D-corrections of Amarsi et al. (2020), we obtained $\log\varepsilon_{\odot,N}$(NLTE+3D) = 7.88$\pm$0.03 for the Sun. Based on high spectral resolution spectra, the NLTE abundances of nitrogen were derived for 11 unevolved A-F type stars with reliable atmospheric parameters. Non-LTE leads to strengthened N I lines, and the non-LTE effects grow with increasing effective temperature. For each star, non-LTE leads to smaller abundance error compared to the LTE case. For superficially normal A stars, non-LTE removes the enhancements relative to the solar nitrogen abundance obtained in the LTE case. A $\lambda$ Boo-type star HD 172167 (Vega) also has close-to-solar N abundance. The four Am stars reveal a scatter of the N abundances, from [N/H] = -0.44 to [N/H] = 0.39. The N abundances of the Sun and superficially normal A stars are consistent within 0.09 dex with the nitrogen abundance of the interstellar gas and the early B-type stars.

Kaniadakis ($\kappa$-deformed) statistics is being widely used for describing relativistic systems with non-extensive behavior and/or interactions. It is built upon a one-parameter generalization of the classical Boltzmann-Gibbs-Shannon entropy, possessing the latter as a particular sub-case. Recently, Kaniadakis model has been adapted to accommodate the complexities of systems under the influence of gravity. The ensuing framework exhibits a rich phenomenology that allows for a deeper understanding of the most extreme conditions of the Universe. Here we present the state-of-the-art of $\kappa$-statistics, discussing its virtues and drawbacks at different energy scales. Special focus is dedicated to gravitational and cosmological implications, including effects on the expanding Universe in dark energy scenarios. This review highlights the versatility of Kaniadakis paradigm, demonstrating its broad application across various fields and setting the stage for further advancements in statistical modeling and theoretical physics.

Both simulations and observations suggest that the disk assembly of galaxies is governed by the interplay between coplanar gas inflow, ex-planar gas outflow and in-situ star formation on the disk, known as the leaky accretion disk. This scenario predicts a strong connection between radial distributions of star formation and chemical abundances. The Milky Way, being the sole galaxy where we can reliably measure star formation histories and the corresponding temporally-resolved chemical abundances with individual stars, provides a unique opportunity to scrutinize this scenario. Based on the recent large spectroscopic and photometric surveys of Milky Way stars, we obtain the radial profiles of magnesium abundance ([Mg/H]) and star formation rate (SFR) surface density at different lookback time. We find the radial profiles of [Mg/H] can be well-reproduced using the leaky accretion disk model with only two free parameters for stars formed within 4 Gyr, as well as the flattening at large radii of metallicity profiles traced by HII regions and Cepheids. Furthermore, the constraint effective yield of the Milky Way and nearby galaxies show broad consistency with the theoretical predictions from stellar chemical evolution model with a mass-loading factor of 0-2. These results support that the recent assembly of the Milky Way adheres to the leaky accretion disk scenario, bridging the disk formation of our home galaxy to the big picture of disk formation in the Universe.

We use a sample of 64 nearby (D=7-45 Mpc) disk galaxies including 45 AGN and 19 non-AGN, that have high spatial resolution multiline CO observations obtained with the ALMA and/or PdBI arrays to study the distribution of cold molecular gas in their circumunuclear disks (CND). We analyze whether the concentration of cold molecular gas changes as a function of the X-ray luminosity in the 2-10 keV range ($L_{\rm X}$). We also study the concentration of the hot molecular gas using NIR data obtained for the H2 1-0S(1) line. We find a turnover in the distribution of the cold molecular gas concentration as a function of $L_{\rm X}$ with a breakpoint which divides the sample into two branches: the AGN build-up branch ($L_{\rm X}\leq10^{41.5\pm0.3}$erg/s) and the AGN feedback branch ($L_{\rm X}\geq10^{41.5\pm0.3}$erg/s) . Lower luminosity AGN and non-AGN of the AGN build-up branch show high cold molecular gas concentrations and centrally peaked radial profiles on nuclear ($r\leq50$~pc) scales. Higher luminosity AGN of the AGN feedback branch, show a sharp decrease in the concentration of molecular gas and flat or inverted radial profiles. The cold molecular gas concentration index ($CCI$), defined as the ratio of surface densities at $r\leq50$~pc and $r\leq200$~pc , namely $CCI \equiv$~log$_{\rm 10}(\Sigma^{\rm gas}_{\rm 50}/\Sigma^{\rm gas}_{\rm 200}$), spans a factor ~4-5 between the galaxies lying at the high end of the AGN build-up branch and the galaxies of the AGN feedback branch. The concentration and radial distributions of the hot molecular gas in our sample follow less extreme trends as a function of the X-ray luminosity. These observations confirm, on a three times larger sample, previous evidence found by the GATOS survey that the imprint of AGN feedback on the CND-scale distribution of molecular gas is more extreme in higher luminosity Seyfert galaxies of the local universe.

We present a systematic study of mid-infrared spectra of galaxies including star-forming galaxies and Active Galactic Nuclei observed with JWST MIRI-MRS and NIRSpec-IFU. We focus on the relative variations of the 3.3, 6.2, 7.7, 11.3, 12.7 and 17 micron Polycyclic Aromatic Hydrocarbon (PAH) features within spatially resolved regions of galaxies including NGC 3256, NGC 7469, VV 114, II Zw96 and NGC 5728. Using theoretical PAH models and extending our earlier work, we introduce a new PAH diagnostic involving the 17 micron PAH feature. To determine the drivers of PAH band variations in galaxies, we compare observed PAH spectral bands to predictions from theoretical PAH models. We consider extinction, dehydrogenation and PAH size and charge as possible drivers of PAH band variations. We find a surprising uniformity in PAH size distribution among the spatially resolved regions of the galaxies studied here, with no evidence for preferential destruction of the smallest grains, contrary to earlier findings. Neither extinction nor dehydrogenation play a crucial role in setting the observed PAH bands. Instead, we find that PAH charge plays a significant role in PAH inter-band variations. We find a tight relation between PAH charge and the intensity of the radiation field as traced by the [NeIII]/[NeII] maps. In agreement with recent JWST results, we find a predominance of neutral PAH molecules in the nuclei of Active Galaxies and their outflows. Ionised PAHs are the dominant population in star-forming galaxies. We discuss the implications of our findings for the use of PAHs as ISM tracers in high redshift galaxies.

Primordial black holes (PBHs) may be part of the dark matter. It is shown here that PBHs form more easily during cosmic phase transitions. For approximately scale-invariant primordial curvature fluctuations the PBH mass function may therefore leave a record of the thermal history of the early Universe. In particular a peak is expected on the 1.9 solar mass scale due to the cosmic QCD transition.

Pulsars are rapidly rotating neutron stars that emit radiation across the electromagnetic spectrum, from radio to gamma-rays. We use the rapid binary population synthesis suite COMPAS to model the Galactic population of canonical pulsars. We account for both radio and gamma-ray selection effects, as well as the motion of pulsars in the Galactic potential due to natal kicks. We compare our models to the catalogs of pulsars detected in the radio, and those detected in gamma-rays by Fermi, and find broad agreement with both populations. We reproduce the observed ratio of radio-loud to radio-quiet gamma-ray pulsars. We further examine the possibility of low spin-down luminosity (Edot) pulsars emitting weak, unpulsed gamma-ray emission and attempt to match this with recent stacking results. We demonstrate that the apparent correlation between the latitude of a pulsar and its Edot arises due to natal kicks imparted to pulsars at birth, assuming that all pulsars are born in the Galactic disk.

3C 275.1 is a blue quasar at $z=0.55522$, hosting powerful outflows and residing in a complex environment. We present a serendipitously detected giant nebula surrounding 3C 275.1, which shows morphological features resembling those of objects known as "jellyfish galaxy", with extremely long tails of ionized gas extending to 170 kpc in projection. We analyze its optical spectra taken by the MUSE on the VLT. The brighter part of this giant nebula exceeds 100 kpc, whose rotation curve does not flatten out, is very different from those of normal spiral galaxies. This system shares some characteristics common to those formed via ram pressure stripping (RPS), yet its long narrow tails and higher ionization are unusual compared to known tails in jellyfish galaxies, not fully consistent with a simple RPS scenario. Our photoionization simulation and the inferred short recombination timescale both suggest that besides the quasar 3C 275.1, an extra source of ionization is necessary to keep the gas ionized at such distance from the nucleus, which could be related to RPS, tidal interaction or AGN outflow, providing new evidence of active dynamical interaction of a galaxy with the intracluster medium.

This second paper presents an in-depth analysis of the composition of the planetary material that has been accreted onto seven white dwarfs with circumstellar dust and gas emission discs with abundances reported in Paper I. The white dwarfs are accreting planetary bodies with a wide range of oxygen, carbon, and sulfur volatile contents, including one white dwarf that shows the most enhanced sulfur abundance seen to date. Three white dwarfs show tentative evidence (2-3$\sigma$) of accreting oxygen-rich material, potentially from water-rich bodies, whilst two others are accreting dry, rocky material. One white dwarf is accreting a mantle-rich fragment of a larger differentiated body, whilst two white dwarfs show an enhancement in their iron abundance and could be accreting core-rich fragments. Whilst most planetary material accreted by white dwarfs display chondritic or bulk Earth-like compositions, these observations demonstrate that core-mantle differentiation, disruptive collisions, and the accretion of core-mantle differentiated material are important. Less than one percent of polluted white dwarfs host both observable circumstellar gas and dust. It is unknown whether these systems are experiencing an early phase in the disruption and accretion of planetary bodies, or alternatively if they are accreting larger planetary bodies. From this work there is no substantial evidence for significant differences in the accreted refractory abundance ratios for those white dwarfs with or without circumstellar gas, but there is tentative evidence for those with circumstellar gas discs to be accreting more water rich material which may suggest that volatiles accrete earlier in a gas-rich phase.

The Atacama Large Aperture Submillimeter Telescope (AtLAST) aims to be the premier next generation large diameter (50-meter) single dish observatory capable of observations across the millimeter/sub-millimeter spectrum, from 30 to 950~GHz. The large primary mirror diameter, the 2-degree field of view and its large 4.7-meter focal surface give AtLAST a high throughput (aperture size times field of view) and grasp (throughput times spectral reach), with the ability to illuminate $>\mathcal{O}(10^7)$ detectors. The optical design concept for AtLAST consists of a numerically optimized two-mirror Ritchey-Chrétien system with an additional flat folding mirror, which enables a quick selection among its planned six instrument positions. We present the optical design concept and discuss the expected optical performance of AtLAST. We then present design concepts that can be implemented in the receiver and instrument optics to correct for astigmatism and mitigate the high degree of curvature of the focal surface in order to recover significant fractions of the geometric field of view at sub-millimeter wavelengths.

AT 2022cmc is a recently documented tidal disruption event (TDE) that exhibits a luminous jet, accompanied by fast-declining X-ray and long-lasting radio/millimeter emission. Motivated by the distinct spectral and temporal signatures between X-ray and radio observations, we propose a multizone model involving relativistic jets with different Lorentz factors. We systematically study the evolution of the faster and slower jets in an external density profile, considering the continuous energy injection rate associated with the time-dependent accretion rates before and after the mass fallback time. We investigate time-dependent multiwavelength emission from both the forward shock and reverse shock regions of the fast and slow jets, in a self-consistent manner. Our analysis demonstrates that the energy injection rate can significantly impact the jet evolution and subsequently influence the lightcurves. We find that the X-ray spectra and lightcurves can be described by the electron synchrotron emission from the reverse shock of the faster jet, in which the late-time X-ray upper limits, extending to 400 days after the disruption, could be interpreted as the jet break steepening. Meanwhile, the radio observations can be interpreted as a result of synchrotron emissions from the forward shock region of the slower jet. We also discuss prospects for testing the model with current and future observations.

This study, placed in the context of the preparation for the Uranus Orbiter Probe mission, aims to predict the bulk volatile compositions of Uranus and Neptune. Using a protoplanetary disk model, it examines the evolution of trace species through vapor and solid transport as dust and pebbles. Due to the high carbon abundance found in their envelopes, the two planets are postulated to have formed at the carbon monoxide iceline within the protosolar nebula. The time evolution of the abundances of the major volatile species at the location of the CO iceline is then calculated to derive the abundance ratios of the corresponding key elements, including the heavy noble gases, in the feeding zones of Uranus and Neptune. Supersolar metallicity in their envelopes likely results from accreting solids in these zones. Two types of solids are considered: pure condensates (Case 1) and a mixture of pure condensates and clathrates (Case 2). The model, calibrated to observed carbon enrichments, predicts deep compositions. In Case 1, argon is deeply depleted, while nitrogen, oxygen, krypton, phosphorus, sulfur, and xenon are significantly enriched relative to their protosolar abundances in the two planets. Case 2 predicts significant enrichments for all species, including argon, relative to their protosolar abundances. Consequently, Case 1 predicts near-zero Ar/Kr or Ar/Xe ratios, while Case 2 suggests these ratios are 0.1 and 0.5-1 times their protosolar ratios. Both cases predict a bulk sulfur-to-nitrogen ratio consistent with atmospheric measurements.

The origin of strong sodium absorption, which has been observed for a few nearby Type Ia supernovae (SNe Ia), remains elusive. Here we analyse two high-signal-to-noise, intermediate-resolution VLT/X-shooter spectra at epochs $+$18 and $+$27 days past peak brightness of the strongly lensed and multiply-imaged Type Ia SN 2016geu which exploded at a redshift of $z = 0.4$. We show that SN 2016geu exhibits very strong, multiple Na I and Ca II absorption lines with a large total Na I D restframe equivalent width of 5.2 $\pm$ 0.2 A, among the highest ever detected for a SN Ia and similar to only a handful of nearby SNe Ia with extraordinary large Na I D EWs. The absorption system is time-invariant and extends over a large velocity span $\sim$ 250 km s$^{-1}$. The majority of the absorption is blueshifted relative to the strongest component, while there are both blueshifted and redshifted components relative to the systemic redshift of the galaxy. The column density ratios and widths of the absorption lines indicate that the absorption likely arises from a combination of interstellar dusty molecular clouds and circumgalactic in- and outflowing material, rather than circumstellar matter around the SN.

The full sky measurements of the Cosmic Microwave Background (CMB) temperature anisotropies by $\textit{WMAP}$ and $\textit{Planck}$ have highlighted the presence of several unexpected isotropy-breaking features on the largest angular scales. In this work, we investigate the impact of the local large-scale structure on these anomalies through the thermal and kinetic Sunyaev-Zeldovich effects. We use a constrained hydrodynamical simulation that reproduces the local Universe in a box of $500\,h^{-1}\,$Mpc to construct full sky maps of the temperature anisotropies produced by these two CMB secondary effects and discuss their statistical properties on large angular scales. We show the significant role played by the Virgo cluster on these scales, and compare it to theoretical predictions and random patches of the universe obtained from the hydrodynamical simulation $\textit{Magneticum}$. We explore three of the main CMB large-scale anomalies -- i.e., lack of correlation, quadrupole-octopole alignment and hemispherical asymmetry -- , both in the latest $\textit{Planck}$ data (PR4), where they are detected at a similar level to the previous releases, and using the simulated secondaries from the local Universe, verifying their negligible impact.

We present a search for luminous, long-duration ambiguous nuclear transients (ANTs) similar to the unprecedented discovery of the extreme, ambiguous event AT2021lwx with a $>150$ d rise time and luminosity $10^{45.7}$ erg s$^{-1}$. We use the Lasair transient broker to search Zwicky Transient Facility (ZTF) data for transients lasting more than one year and exhibiting smooth declines. Our search returns 59 events, seven of which we classify as ANTs assumed to be driven by accretion onto supermassive black holes. We propose the remaining 52 are stochastic variability from regular supermassive black hole accretion rather than distinct transients. We supplement the seven ANTs with three nuclear transients in ZTF that fail the light curve selection but have clear single flares and spectra that do not resemble typical AGN. All but one of these 10 ANTs have a mid-infrared flare from an assumed dust echo, implying the ubiquity of dust around the black holes giving rise to ANTs. No events are more luminous than AT2021lwx, but one (ZTF19aamrjar) has twice the duration and a higher integrated energy release. On the other extreme, ZTF20abodaps reaches a luminosity close to AT2021lwx with a rise time $<20$ d and that fades smoothly in $>600$ d. We define a portion of rise-time versus flare amplitude space that selects ANTs with $\sim50$ per cent purity against variable active galactic nuclei. We calculate a volumetric rate of $\gtrsim 3\times10^{-11}$ Mpc$^{-1}$ yr$^{-1}$, consistent with the events being caused by tidal disruptions of intermediate and high-mass stars.

Context. A thousand new magnetic candidate CP stars have been identified with LAMOST, among which about 700 prime targets have rotational modulation determined from TESS. Aims. We aim to check for the presence of a magnetic field in a subsample of these LAMOST CP stars, test the viability of the 5200 A depression used to select the mCP candidates in the LAMOST survey as a reliable indicator of magnetism, and expand on the limited database of known magnetic hot stars. The sample includes some pulsators that would be valuable targets for magneto-asteroseismology. Methods. We selected approx. 100 magnetic candidate LAMOST CP stars, presenting a depression at 5200 A in their spectrum and that also display rotational modulation in their TESS photometric lightcurves. We obtained spectropolarimetric observations of 39 targets from this sample with ESPaDOnS at CFHT. We utilise the Least Squares Deconvolution method to generate the mean profile of the Stokes V and I parameters, from which the longitudinal magnetic field strength for each target can be determined. For HD 49198, we performed more in-depth analysis to determine the polar magnetic field strength and configuration. Results. We detect fields in at least 36 of our sample of 39 targets. This success rate in detecting magnetic field (above 92%) is very high compared to the occurrence of magnetic fields in hot stars (about 10%). Four of these newly discovered magnetic stars are magnetic pulsators. In particular, we detect the strongest field around a delta Scuti star discovered to date: a 12 kG dipolar field in HD 49198. Conclusions. From our analysis, we conclude that using the 5200 A depression displayed in the spectra in combination with rotational modulation in photometric data is a very reliable method for identifying magnetic candidates in this population of stars.

ESA's PLATO mission aims the detection and characterization of terrestrial planets around solar-type stars as well as the study of host star properties. The noise-to-signal ratio (NSR) is the main performance parameter of the PLATO instrument, which consists of 24 Normal Cameras and 2 Fast Cameras. In order to justify, verify and breakdown NSR-relevant requirements the software simulator PINE was developed. PINE models the signal pathway from a target star to the digital output of a camera based on physical models and considers the major noise contributors. In this paper, the simulator's coarse mode is introduced which allows fast performance analyses on instrument level. The added value of PINE is illustrated by exemplary applications.

Optical emission line diagnostics, which are a common tool to constrain the properties of the interstellar medium (ISM) of galaxies, become progressively inaccessible at higher redshifts for ground-based facilities. Far-infrared (FIR) emission lines, which are redshifted into atmospheric windows accessible by ground-based sub-millimeter facilities, could provide alternative ISM diagnostics to optical emission lines. We investigate FIR line ratios involving [CII]$\lambda 158 \mu$m, [OIII]$\lambda 88 \mu$m, [OIII]$\lambda 52 \mu$m, [NII]$\lambda 122 \mu$m and [NIII$\lambda 57 \mu$m, using synthetic emission lines applied to a high-resolution (m$_{\rm gas}$= 883.4 M$_{\odot}$) cosmological zoom-in simulation, including radiative-transfer post processing with KramsesRT at z = 6.5. We find that the [CII]/[NII]122 ratio is sensitive to the temperature and density of photo-dissociation regions, and thus could be a useful tool to trace the properties of this gas phase in galaxies. We also find that [NII]/[NIII] is a good tracer of the temperature and [OIII]52/[OIII]88 a good tracer of the gas density of HII regions. Emission line ratios containing the [OIII]$\lambda 88 \mu$m line are sensitive to high velocity outflowing gas.

The stellar structures of star-forming galaxies (SFGs) undergo significant size growth during their mass assembly and must pass through a compaction phase as they evolve into quiescent galaxies (QGs). To shed light on the mechanisms behind this structural evolution, we study the morphology of the star-forming components of 665 SFGs at 0<z<2.5 measured using JWST/MIRI observation and compare them with the morphology of their stellar components taken from the literature. The stellar and star-forming components of most SFGs (66%) have extended disk-like structures that are aligned with each other and are of the same size. The star-forming components of these galaxies follow a mass-size relation, similar to that followed by their stellar components. At the highest mass, the optical Sérsic index of these SFGs increases to 2.5, suggesting the presence of a dominant stellar bulge. Because their star-forming components remain disk-like, these bulges cannot have formed by secular in-situ growth. We identify a second population of galaxies lying below the MIR mass-size relation, with compact star-forming components embedded in extended stellar components (EC galaxy). These galaxies are overall rare (15%) but become more dominant (30%) at high mass ($>10^{10.5}M_\odot$). The compact star-forming components of these galaxies are also concentrated and slightly spheroidal, suggesting that this compaction phase can build dense bulge in-situ. Finally, we identify a third population of SFGs (19%), with both compact stellar and star-forming components. The density of their stellar cores resemble those of QGs and are compatible with being the descendants of EC galaxy. Overall, the structural evolution of SFGs is mainly dominated by a secular inside-out growth, which can, however, be interrupted by violent compaction phase(s) that can build dominant stellar bulges like those in massive SFGs or QGs.

This tutorial covers the use of absolute astrometry, in particular from the combination of the Hipparcos and Gaia missions, to identify faint companions to nearby stars and to measure the masses and orbits of those companions. Absolute astrometry has been used with increasing success to discover new planets and brown dwarfs and to measure masses and orbits for systems with periods as long as centuries. This tutorial summarizes the nature of the underlying astrometric data, the approach typically used to fit orbits, and the assumptions about that data implicit throughout the process. It attempts to provide intuition for the sensitivity of astrometry as a function of stellar and companion properties and how the available constraints depend on the character and quantity of data available. This tutorial is written for someone with some background in astronomy but with no more than a minimal acquaintance with astrometry or orbit fitting.

Sympathetic eruptions of solar prominences have been studied for decades, however, it is usually difficult to identify their causal links. Here we present two failed prominence eruptions on 26 October 2022 and explore their connections. Using stereoscopic observations, the south prominence (PRO-S) erupts with untwisting motions, flare ribbons occur underneath, and new connections are formed during the eruption. The north prominence (PRO-N) rises up along with PRO-S, and its upper part disappears due to catastrophic mass draining along an elongated structure after PRO-S failed eruption. We suggest that the eruption of PRO-S initiates due to a kink instability, further rises up, and fails to erupt due to reconnection with surrounding fields. The elongated structure connecting PRO-N overlies PRO-S, which causes the rising up of PRO-N along with PRO-S and mass drainage after PRO-S eruption. This study suggests that a prominence may end its life through mass drainage forced by an eruption underneath.

The cosmic expansion rate can be directly measured with gravitational waves (GWs) of the compact binary mergers, by jointly constraining the mass function of the population and the cosmological model via the so called spectral sirens. Such a method relies on the features in the mass functions, which may originate from some individual sub-populations, and hence become blurred/indistinct due to the superposition of different sub-populations. In this work we propose a novel approach to constrain the cosmic expansion rate with sub-populations of GW events, named multi-spectral sirens. We illustrate the advantage of the multi-spectral sirens compared to the traditional spectral sirens by simulation with mock data. The application of this approach to the GWTC-3 data yields $H_0=73.25^{+29.87}_{-25.55}~{\rm Mpc}^{-1}~{\rm km}~{\rm s}^{-1}$ (median and symmetric 68.3\% credible level). The incorporation of the bright standard siren GW170817 with a uniform prior in $ [10,200] ~{\rm Mpc}^{-1}~{\rm km}~{\rm s}^{-1}$ gives $H_0=72.38^{+15.03}_{-9.13}~{\rm Mpc}^{-1}~{\rm km}~{\rm s}^{-1}$ (68.3\% confidence level), corresponding to an improvement of $\sim28\%$ with respect to the measurement from sole GW170817.

We propose and discuss a new experimental approach to measure the centroid shift induced by gravitational microlensing in the images of lensed quasars (astrometric microlensing). Our strategy is based on taking the photocenter of a region in the quasar large enough as to be insensitive to microlensing as reference to measure the centroid displacement of the continuum. In this way, single-epoch measurements of astrometric microlensing can be performed. Using numerical simulations, we show that, indeed, the centroid shift monotonically decreases as the size of the emitting region increases, and only for relatively large regions, like the broad line region (BLR), does the centroid shift become negligible. This opens interesting possibilities to study the stratification of the different emitters in the accretion disk and the BLR. We estimate the amplitude of the centroid shifts for 79 gravitationally lensed images and study more thoroughly the special cases Q2237+030 A, RXJ1131-1231 A, PG1115+080 A2 and SDSS J1004+4112 A. We propose to use spectro-astrometry to simultaneously obtain the photocenters of the continuum and of different emission line regions since, with the precision of forthcoming instruments, astrometric microlensing by $\sim 1 M_\odot$ mass microlenses may be detected in many quasar lensed images. When we consider more massive micro/millilenses, $M\gtrsim 10 M_\odot$, often proposed as the constituents of dark matter, the BLR becomes sensitive to microlensing and can no longer be used as a positional reference to measure centroid shifts. Differential microlensing between the images of a lensed quasar along several epochs should be used instead.

Star-galaxy separation is a crucial step in creating target catalogues for extragalactic spectroscopic surveys. A classifier biased towards inclusivity risks including spurious stars, wasting fibre hours, while a more conservative classifier might overlook galaxies, compromising completeness and hence survey objectives. To avoid bias introduced by a training set in supervised methods, we employ an unsupervised machine learning approach. Using photometry from the Wide Area VISTA Extragalactic Survey (WAVES)-Wide catalogue comprising 9-band $u-K_s$ data, we create a feature space with colours, fluxes, and apparent size information extracted by ${\rm P{\scriptsize RO} F{\scriptsize OUND}}$. We apply the non-linear dimensionality reduction method UMAP (Uniform Manifold Approximation and Projection) combined with the classifier ${\rm{\scriptsize HDBSCAN}}$ to classify stars and galaxies. Our method is verified against a baseline colour and morphological method using a truth catalogue from Gaia, SDSS, GAMA, and DESI. We correctly identify 99.72% of galaxies within the AB magnitude limit of $Z = 21.2$, with an F1 score of 0.9970 across the entire ground truth sample, compared to 0.9871 from the baseline method. Our method's higher purity (0.9966) compared to the baseline (0.9780) increases efficiency, identifying 11% fewer galaxy or ambiguous sources, saving approximately 70,000 fibre hours on the 4MOST instrument. We achieve reliable classification statistics for challenging sources including quasars, compact galaxies, and low surface brightness galaxies, retrieving 95.1%, 84.6%, and 99.5% of them respectively. Angular clustering analysis validates our classifications, showing consistency with expected galaxy clustering, regardless of the baseline classification.

While high resolution ALMA observations reveal a wealth of substructure in protoplanetary discs, they remain incapable of resolving the types of small scale dust structures predicted, for example, by numerical simulations of the streaming instability. In this Letter, we propose a method to find evidence for unresolved, optically thick dusty rings in protoplanetary disks. We demonstrate that, in presence of unresolved rings, the brightness of an inclined disc exhibits a distinctive emission peak at the minor axis. Furthermore, the azimuthal brightness depends on both the geometry of the rings and the dust optical properties; we can therefore use the azimuthal brightness variations to both detect unresolved rings and probe their properties. By analyzing the azimuthal brightness in the test-case of ring-like substructures formed by streaming instability, we show that the resulting peak is likely detectable by ALMA for typical disc parameters. Moreover, we present an analytic model that not only qualitatively but also quantitatively reproduces the peak found in the simulations, validating its applicability to infer the presence of unresolved rings in observations and characterize their optical properties and shape. This will contribute to the identification of disk regions where streaming instability (and thus planet formation) is occurring.

Planets may be rotationally flattened, and their oblateness thus provide useful information on their formation and evolution. Here we develop a new algorithm that can compute the transit light curve due to an oblate planet very efficiently and use it to study the detectability of planet oblateness (and spin obliquity) with the James Webb Space Telescope (JWST). Using the Jupiter analog, Kepler-167e, as an example, we show that observations of a single transit with JWST are able to detect a Saturn-like oblateness ($f=0.1$) with high confidence, or set a stringent upper limit on the oblateness parameter, as long as the planetary spin is slightly misaligned ($\gtrsim 20^\circ$) with respect to its orbital direction. Based on known obliquity measurements and theoretical arguments, it is reasonable to believe that this level of misalignment may be common. We estimate the sensitivity limit of JWST in oblateness detections and highlight the importance of better characterizations of cold planets in planning future JWST transit observations. The potential to detect rings, moons, and atmospheric species of the cold giants with JWST is also discussed.

We present AsterX, a novel open-source, GPU-accelerated, fully general relativistic magnetohydrodynamic (GRMHD) code designed for dynamic spacetimes in 3D Cartesian coordinates, and tailored for exascale computing. We utilize block-structured adaptive mesh refinement (AMR) through CarpetX, the new driver for the Einstein Toolkit, which is built on AMReX, a software framework for massively parallel applications. AsterX employs the Valencia formulation for GRMHD, coupled with the 'Z4c' formalism for spacetime evolution, while incorporating high resolution shock capturing schemes to accurately handle the hydrodynamics. AsterX has undergone rigorous testing in both static and dynamic spacetime, demonstrating remarkable accuracy and agreement with other codes in literature. Benchmarking the code through scaling tests on OLCF's Frontier supercomputer, we demonstrate a weak scaling efficiency of about 67%-77% on 4096 nodes compared to an 8-node performance.

The unprecedented statistics of detected Type Ia supernovae (SNe Ia) brought by the Zwicky Transient Facility enables us to probe the impact of the Large-Scale Structure on the properties of these objects. The goal of this paper is to explore the possible impact of the under-dense part of the large-scale structure on the intrinsic SALT2 light curve properties of SNe Ia and uncover possible biases in SN Ia analyses. With a volume-limited selection of ZTF-Cosmo-DR2 Type Ia supernovae overlapping with the SDSS-DR7 survey footprint, we investigate the distribution of their properties with regard to voids detected in the SDSS-DR7 galaxy sample. We further use Voronoi volumes as proxy for local density environments within the large-scale structure. We find a moderate dependency of the stretch toward the localisation around the void centre and none when considering colour. The local Voronoi volumes mostly affect the fraction of low/high stretch supernovae. With the current statistics available, we consider that the impact of high or low local density environment can be considered as a proxy for the colour of the host galaxy. Under-dense environments should not cause any biases in supernova analyses.

The properties of satellite dwarf galaxies pose important empirical constraints to verify cosmological models on galaxy scales. Their phase-space correlations, in particular, offer interesting insights into various models. Next to the planes-of-satellites phenomenon, the lopsided distribution of satellites relative to their host galaxy has been studied observationally and in cosmological simulations. It is still unclear how observed lopsidedness aligns with expectations from simulations. We measure lopsidedness in observed isolated satellite systems using six different metrics. We study 47 systems from the MATLAS survey beyond the Local Volume (LV) as well as 21 LV satellite systems from the ELVES survey. We find that the so-called wedge metric, counting the number of dwarfs in wedges with varying opening angles, is best suited to capture a system's overall lopsidedness. Under this metric, our analysis reveals that ~16 percent of the tested satellite systems exhibit a statistically significant degree of lopsidedness when compared to systems with randomly generated satellite position angles. This presents a notable excess over the expected 5% (2 sigma level) of significantly lopsided systems in a sample with no overall inherent lopsidedness. However, using multiple metrics provides a more complete picture. Combining all tested metrics, the number of significantly lopsided systems increases to ~21 percent. Contrary to recent results from the literature, we find more lopsided systems among the red early-type galaxies in the MATLAS survey compared to the mostly blue late-type hosts in ELVES. We further find that satellite galaxies at larger distances from the host, potentially recently accreted, are likely the primary contributors to the reported excess of lopsidedness. Our results enable comparisons with similar systems in simulations to assess consistency with the standard model.

The search for a space-time variation of the fundamental constants has been explored over the years to test our physical theories. In this paper, we use the dispersion measure ($DM$) of fast radio bursts (FRB) combined with type Ia supernovae (SNe) data to investigate a possible redshift evolution of the fine-structure constant ($\alpha$), considering the runaway dilaton scenario, which predicts $\frac{\Delta \alpha}{\alpha} = - \gamma\ln{(1+z)}$, where $\gamma$ is a constant proportional to the current value of the coupling between the dilaton field and hadronic matter. We derive all the relevant expressions for the $DM$ dependence concerning the fine-structure constant and constrain the parameter $\gamma$ from measurements of 17 well-localized FRBs and 1048 SNe data from the Pantheon compilation. We also use Monte Carlo simulations to forecast the constraining power of larger samples of FRB measurements for data sets with $N = 500$ and $N = 1000$ points. We found that the uncertainty on $\gamma$ can be improved by one order of magnitude and that limits on $\frac{\Delta \alpha}{\alpha}$ beyond $\sigma \sim 10^{-2}$ will depend crucially on better control of statistical and systematic uncertainties of upcoming FRB data.

MHD kink instability can trigger the fragmentation of a twisted magnetic flux tube into small-scale current sheets that dissipate as aperiodic impulsive heating events. This instability propagates as an avalanche to nearby flux tubes and leads to a nanoflare storm. Our previous work was devoted to related 3D MHD numerical modeling with a stratified and realistic atmosphere. This work addresses predictions for the EUV imaging spectroscopy of such structure and evolution of a loop, with an average temperature of 2.5 MK in the solar corona. We set a particular focus on the forthcoming MUSE mission. From the output of the numerical simulations, we synthesized the intensities, Doppler shifts, and non-thermal line broadening in 3 EUV spectral lines in the MUSE passbands: Fe IX 171A, Fe XV 284 A, and Fe XIX 108 A, at 1 MK, 2 MK, and 10 MK, respectively, according to the MUSE expected pixel size, temporal resolution, and temperature response functions. We provide maps showing different view angles and realistic spectra. Finally, we discuss the relevant evolutionary processes from the perspective of possible observations. We find that the MUSE observations might be able to detect the fine structure determined by tube fragmentation. In particular, the Fe IX line is mostly emitted at the loop footpoints, where we track the motions that drive the magnetic stressing and detect the upward motion of evaporating plasma from the chromosphere. In Fe XV, we see the bulk of the loop with increasing intensity. The Fe XIX line is very faint within the chosen simulation parameters; thus, any transient brightening around the loop apex may possibly be emphasized by the folding of sheet-like structure. In conclusion, we show that coronal loop observations with MUSE can pinpoint some crucial features of MHD-modeled ignition processes, such as the related dynamics, helping to identify the heating processes.

We study detection prospects of a gravitational-wave background (GWB) sourced by SU(2) gauge fields considering all possible observational constraints. More precisely, we consider bounds set by cosmic microwave background measurements, primordial black hole overproduction, as well as backreaction of the gauge fields on the background evolution. Gravitational-waves data from the first three observing runs of the LIGO-Virgo-KAGRA Collaboration show no evidence for a GWB contribution from axion inflation. However, we are able to place conservative constraints on the parameters of the SU(2) inflation with current data. We investigate conditions on the inflationary potential that would lead to a detectable signal that evades astrophysical and cosmological constraints and discuss detection prospects for third generation networks.

The WHT Enhanced Area Velocity Explorer (WEAVE) is a new, massively multiplexing spectrograph. This new instrument will be exploited to obtain high S/N spectra of $\sim$25000 galaxies at intermediate redshifts for the WEAVE Stellar Population Survey (WEAVE-StePS). We test machine learning methods for retrieving the key physical parameters of galaxies from WEAVE-StePS-like spectra using both photometric and spectroscopic information at various S/Ns and redshifts. We simulated $\sim$105000 galaxy spectra assuming SFH with an exponentially declining star formation rate, covering a wide range of ages, stellar metallicities, sSFRs, and dust extinctions. We then evaluated the ability of the random forest and KNN algorithms to correctly predict such parameters assuming no measurement errors. We checked how much the predictive ability deteriorates for different S/Ns and redshifts, finding that both algorithms still accurately estimate the ages and metallicities with low bias. The dispersion varies from 0.08-0.16 dex for ages and 0.11-0.25 dex for metallicity, depending on the redshift and S/N. For dust attenuation, we find a similarly low bias and dispersion. For the sSFR, we find a very good constraining power for star-forming galaxies, log sSFR$\gtrsim$ -11, where the bias is $\sim$ 0.01 dex and the dispersion is $\sim$ 0.10 dex. For more quiescent galaxies, with log sSFR$\lesssim$ -11, we find a higher bias, 0.61-0.86 dex, and a higher dispersion, $\sim$ 0.4 dex, for different S/Ns and redshifts. Generally, we find that the RF outperforms the KNN. Finally, the retrieved sSFR was used to successfully classify galaxies as part of the blue cloud, green valley, or red sequence. We demonstrate that machine learning algorithms can accurately estimate the physical parameters of simulated galaxies even at relatively low S/N=10 per angstrom spectra with available ancillary photometric information.

We report the first arcsecond-resolution observations of the magnetic field in the mini starburst complex Sgr B2. SMA polarization observations revealed magnetic field morphology in three dense cores of Sgr B2 N(orth), M(ain), and S(outh). The total plane-of-sky magnetic field strengths in these cores are estimated to be 4.3-10.0 mG, 6.2-14.7 mG, and 1.9-4.5 mG derived from the angular dispersion function method after applying the correction factors of 0.21 and 0.5. Combining with analyses of the parsec-scale polarization data from SOFIA, we found that a magnetically supercritical condition is present from the cloud-scale ($\sim$10 pc) to core-scale ($\sim$0.2 pc) in Sgr B2, which is consistent with the burst of star formation activities in the region likely resulted from a multi-scale gravitational collapse from the cloud to dense cores.