Search

Mid-infrared (mid-IR) observations are powerful in identifying heavily obscured active galactic nuclei (AGN) that have weak emission in other wavelengths. Data from the Mid-Infrared Instrument (MIRI) on board the James Webb Space Telescope provides an excellent opportunity to perform such studies. We take advantage of the MIRI imaging data from the Cosmic Evolution Early Release Science Survey to investigate the AGN population in the distant universe. We estimate the source properties of MIRI-selected objects by utilizing spectral energy distribution (SED) modeling, and classify them into star-forming galaxies (SFs), SF-AGN mixed objects, and AGN. The source numbers of these types are 433, 102, and 25, respectively, from four MIRI pointings covering ∼9 arcmin ^2 . The sample spans a redshift range of ≈0–5. We derive the median SEDs for all three source types, respectively, and publicly release them. The median MIRI SED of AGN is similar to the typical SEDs of hot dust-obscured galaxies and Seyfert 2s, for which the mid-IR SEDs are dominated by emission from AGN-heated hot dust. Based on our SED-fit results, we estimate the black hole accretion density (BHAD; i.e., total BH growth rate per comoving volume) as a function of redshift. At z < 3, the resulting BHAD agrees with the X-ray measurements in general. At z > 3, we identify a total of 27 AGN and SF-AGN mixed objects, leading to that our high- z BHAD is substantially higher than the X-ray results (∼0.5 dex at z ≈ 3–5). This difference indicates MIRI can identify a large population of heavily obscured AGN missed by X-ray surveys at high redshifts.

One of the fundamental goals of modern astrophysics is to estimate the physical parameters of galaxies. We present a hierarchical Bayesian model to compute age maps from images in the H α line (taken with Taurus tunable filter, TTF), ultraviolet band (GALEX far UV, FUV), and infrared bands (Spitzer 24, 70, and 160 |$\mu$| m). We present the burst ages for young stellar populations in a sample of nearby and nearly face-on galaxies. The H α to FUV flux ratio is a good relative indicator of the very recent star formation history (SFH). As a nascent star-forming region evolves, the H α line emission declines earlier than the UV continuum, leading to a decrease in the H α/FUV ratio. Using star-forming galaxy models, sampled with a probabilistic formalism, and allowing for a variable fraction of ionizing photons in the clusters, we obtain the corresponding theoretical ratio H α/FUV to compare with our observed flux ratios, and thus to estimate the ages of the observed regions. We take into account the mean uncertainties and the interrelationships between parameters when computing H α/FUV. We propose a Bayesian hierarchical model where a joint probability distribution is defined to determine the parameters (age, metallicity, IMF) from the observed data (the observed flux ratios H α/FUV). The joint distribution of the parameters is described through independent and identically distributed (i.i.d.) random variables generated through MCMC (Markov Chain Monte Carlo) techniques. [ABSTRACT FROM AUTHOR]

The H2O Southern Galactic Plane Survey (HOPS) has mapped 100 deg² of the Galactic plane for water masers and thermal molecular line emission using the 22 m Mopra telescope. We describe the automated spectral-line fitting pipelines used to determine the properties of emission detected in HOPS data cubes, and use these to derive the physical and kinematic properties of gas in the survey. A combination of the angular resolution, sensitivity, velocity resolution and high critical density of lines targeted make the HOPS data cubes ideally suited to finding precursor clouds to the most massive and dense stellar clusters in the Galaxy. We compile a list of the most massive HOPS ammonia regions and investigate whether any may be young massive cluster progenitor gas clouds. HOPS is also ideally suited to trace the flows of dense gas in the Galactic Centre. We find the kinematic structure of gas within the inner 500 pc of the Galaxy is consistent with recent predictions for the dynamical evolution of gas flows in the centre of the Milky Way. We confirm a recent finding that the dense gas in the inner 100 pc has an oscillatory kinematic structure with characteristic length-scale of 20 pc, and also identify similar oscillatory kinematic structure in the gas at radii larger than 100 pc. Finally, we make all of the above fits and the remaining HOPS data cubes across the 100 deg² of the survey available to the community. [ABSTRACT FROM AUTHOR]

We study the distribution and evolution of the stellar mass and the star formation rate (SFR) of the brightest group galaxies (BGGs) over 0.04 < z < 1.3 using a large sample of 407 X-ray galaxy groups selected from the COSMOS, AEGIS, and XMM-LSS fields. We compare our results with predictions from the semi-analytic models based on the Millennium simulation. In contrast to model predictions, we find that, as the Universe evolves, the stellar mass distribution evolves towards a normal distribution. This distribution tends to skew to low-mass BGGs at all redshifts implying the presence of a star-forming population of the BGGs with MS ∼ 1010.5 M⊙ which results in the shape of the stellar mass distribution deviating from a normal distribution. In agreement with the models and previous studies, we find that the mean stellar mass of BGGs grows with time by a factor of ∼2 between z = 1.3 and z = 0.1, however, the significant growth occurs above z = 0.4. The BGGs are not entirely a dormant population of galaxies, as low-mass BGGs in low-mass haloes are more active in forming stars than the BGGs in more massive haloes, over the same redshift range. We find that the average SFR of the BGGs evolves steeply with redshift and fraction of the passive BGGs increases as a function of increasing stellar mass and halo mass. Finally, we show that the specific SFR of the BGGs within haloes with M200 ≤ 1013.4 M⊙ decreases with increasing halo mass at z < 0.4. [ABSTRACT FROM AUTHOR]

We present Magellan/MIKE and Keck/HIRES high-resolution spectra of six red giant stars in the dwarf galaxy Segue 1. Including one additional Segue 1 star observed by Norris et al., high-resolution spectra have now been obtained for every red giant in Segue 1. Remarkably, three of these seven stars have metallicities below [Fe/H] = –3.5, suggesting that Segue 1 is the least chemically evolved galaxy known. We confirm previous medium-resolution analyses demonstrating that Segue 1 stars span a metallicity range of more than 2 dex, from [Fe/H] = –1.4 to [Fe/H] = –3.8. All of the Segue 1 stars are α-enhanced, with [α/Fe] ∼ 0.5. High α-element abundances are typical for metal-poor stars, but in every previously studied galaxy [α/Fe] declines for more metal-rich stars, which is typically interpreted as iron enrichment from supernova Ia. The absence of this signature in Segue 1 indicates that it was enriched exclusively by massive stars. Other light element abundance ratios in Segue 1, including carbon enhancement in the three most metal-poor stars, closely resemble those of metal-poor halo stars. Finally, we classify the most metal-rich star as a CH star given its large overabundances of carbon and s-process elements. The other six stars show remarkably low neutron-capture element abundances of [Sr/H] < –4.9 and [Ba/H] < –4.2, which are comparable to the lowest levels ever detected in halo stars. This suggests minimal neutron-capture enrichment, perhaps limited to a single r-process or weak s-process synthesizing event. Altogether, the chemical abundances of Segue 1 indicate no substantial chemical evolution, supporting the idea that it may be a surviving first galaxy that experienced only one burst of star formation. [ABSTRACT FROM AUTHOR]

We present the completed KMOS3D survey, an integral field spectroscopic survey of 739 galaxies at 0.6 < z < 2.7 using the K-band Multi Object Spectrograph (KMOS) at the Very Large Telescope. The KMOS3D survey provides a population-wide census of kinematics, star formation, outflows, and nebular gas conditions both on and off the star-forming galaxy main sequence through the spatially resolved and integrated properties of Hα, [N ii], and [S ii] emission lines. We detect Hα emission for 91% of galaxies on the main sequence of star formation and 79% overall. The depth of the survey has allowed us to detect galaxies with star formation rates below 1 M⊙ yr−1, as well as to resolve 81% of detected galaxies with ≥3 resolution elements along the kinematic major axis. The detection fraction of Hα is a strong function of both color and offset from the main sequence, with the detected and nondetected samples exhibiting different spectral energy distribution shapes. Comparison of Hα and UV+IR star formation rates reveal that dust attenuation corrections may be underestimated by 0.5 dex at the highest masses (). We confirm our first year results of a high rotation-dominated fraction (monotonic velocity gradient and vrot/) of 77% for the full KMOS3D sample. The rotation-dominated fraction is a function of both stellar mass and redshift, with the strongest evolution measured over the redshift range of the survey for galaxies with . With this paper, we include a final data release of all 739 observed objects (http://www.mpe.mpg.de/ir/KMOS3D). [ABSTRACT FROM AUTHOR]

Using stacked emission-line flux measurements of cool circumgalactic gas (CGM) in lower-mass galaxies (109.0 ≤ M */ M ⊙ ≤ 1010.2), we measure the dependence of the emission characteristics on orientation relative to the disk plane as a function of radius and compare to what we found previously for massive (M * > 1010.4 M ⊙) early-type galaxies. Although the line ratios (the lower [N ii ]/H α and [O iii ]/H β) suggest an overall softer ionizing source than in the more massive galaxies, consistent with previous findings, we find the same ionization hardening signature (a higher [N ii ]/H α ratio in the inner polar region) along the polar direction at small radii that we found for the more massive galaxies. The line ratio in the inner polar bin is distinct from that measured for the inner planar bin with 99.99%, confidence and with >99.9% confidence we conclude that it lies outside the star formation regime. The effective hardening of the ionization of the CGM along the polar axis, at small radii, could indicate either relic effects of active galactic nucleus activity or shock ionization. In either case, this signature appears to be ubiquitous across the stellar mass range we are able to explore with our spectral stacking technique and currently available archival data. [ABSTRACT FROM AUTHOR]

The paper presents results of studying the kinematics of the ionized gas in the galaxy of the Large Magellanic Cloud type NGC 7292 obtained with the 2.5-m telescope of the Caucasian Mountain Observatory (CMO SAI MSU) and the 6-m BTA telescope of the Special Astrophysical Observatory (SAO RAS). Analysis of the velocity fields of the ionized and neutral hydrogen showed that the kinematic center of NGC 7292 located at the center of the bar, northwest of the photometric center of the galaxy (the southeastern end of the bar) previously taken as the center of NGC 7292. In addition to the circular rotation of the gas, the radial motions associated with the bar play a significant role in the kinematics of the disk. The observed perturbations of the gaseous-disk kinematics induced by the ongoing star formation do not exceed those caused by the bar. It is possible that part of the non-circular motions (at the southeastern end of the bar which is the brightest H II region) may be related to the effects of the capture of a dwarf companion or a gaseous cloud. [ABSTRACT FROM AUTHOR]

Information about the papers discussed at the European Space Laboratory (ESLAB) Symposium on Cosmic Cataclysms and Life held in Frascati, Italy from November 10-14, 2008 is presented. Topics include violent processes in star formation, Big Bang and planetary formation. People behind the success of the event include Willy Benz, Agustin Chicarro and Charles Cockell.

In this paper, we investigate the benefits of teaming up data from the radio to the far-infrared (FIR) regime for the characterization of dusty star-forming galaxies (DSFGs). These galaxies are thought to be the star-forming progenitors of local massive quiescent galaxies and to play a pivotal role in the reconstruction of the cosmic star formation rate density up to high redshift. Due to their dust-enshrouded nature, DSFGs are often invisible in the near-infrared/optical/UV bands. Therefore, they necessitate observations at longer wavelengths, primarily the FIR band, where dust emission occurs, and the radio band, which is not affected by dust absorption. Combining data from these two spectral windows makes it possible to characterize even the dustiest objects, enabling the retrieval of information about their age, dust temperature, and star-formation status, and facilitates the differentiation between various galaxy populations that evolve throughout cosmic history. Despite the detection of faint radio sources being a challenging task, this study demonstrates that an effective strategy to build statistically relevant samples of DSFGs would be reaching deep sensitivities in the radio band, even restricted to smaller areas, and then combining these radio observations with FIR/submm data. Additionally, this paper quantifies the improvement in the spectral energy distribution (SED) reconstruction of DSFGs by incorporating ALMA band measurements, in particular, in its upgraded status thanks to the anticipated Wideband Sensitivity Upgrade. [ABSTRACT FROM AUTHOR]

We search for local extremely metal-poor galaxies (EMPGs), selecting photometric candidates by broadband color excess and machine-learning techniques with the SDSS photometric data. After removing stellar contaminants by shallow spectroscopy with Seimei and Nayuta telescopes, we confirm that three candidates are EMPGs with 0.05–0.1 Z ⊙ by deep Magellan/MagE spectroscopy for faint [Oiii] λ 4363 lines. Using a statistical sample consisting of 105 spectroscopically confirmed EMPGs taken from our study and the literature, we calculate the cross-correlation function (CCF) of the EMPGs and all SDSS galaxies to quantify environments of EMPGs. Comparing another CCF of all SDSS galaxies and comparison of SDSS galaxies in the same stellar-mass range (107.0–108.4 M ⊙), we find no significant (>1 σ) difference between these two CCFs. We also compare mass–metallicity relations (MZRs) of the EMPGs and those of galaxies at z ∼ 0–4 with a steady chemical evolution model and find that the EMPG MZR is comparable with the model prediction on average. These clustering and chemical properties of EMPGs are explained by a scenario of stochastic metal-poor gas accretion on metal-rich galaxies showing metal-poor star formation. Extending the broadband color excess technique to a high- z EMPG search, we select 17 candidates of z ∼ 4–5 EMPGs with the deep (≃30 mag) near-infrared JWST/NIRCam images obtained by ERO and ERS programs. We find galaxy candidates with negligible [Oiii] λ λ 4959,5007 emission weaker than the local EMPGs and known high- z galaxies, suggesting that some of these candidates may fall in the range of 0–0.01 Z ⊙, which potentially breaks the lowest metallicity limit known to date. [ABSTRACT FROM AUTHOR]

The James Webb Space Telescope opens a new window to directly probe luminous quasars powered by billion solar mass black holes in the Epoch of Reionization and their coevolution with massive galaxies with unprecedented details. In this paper, we report the first results from a deep NIRSpec integral field unit spectroscopic study of a quasar at z = 7.5. We obtain a bolometric luminosity of ∼1.8 × 1047 erg s−1 and a black hole mass of ∼0.7–2.5 × 109 M ⊙ based on the H β emission line in the quasar spectrum. We discover ∼2 kpc scale, highly blueshifted (∼−870 km s−1) and broad (∼1400 km s−1) [O iii ] line emission after the quasar point-spread function has been subtracted. Such line emission most likely originates from a fast, quasar-driven outflow, the earliest one at galactic scales known so far. The dynamical properties of this outflow fall within the typical ranges of quasar-driven outflows at lower redshift, and the outflow may be fast enough to reach the circumgalactic medium. Combining both the extended and nuclear outflow together, the mass outflow rate, ∼300 M ⊙ yr−1, is ∼60%–380% of the star formation rate of the quasar host galaxy, suggesting that the outflow may expel a significant amount of gas from the inner region of the galaxy. The kinetic energy outflow rate, ∼3.6 × 1044 erg s−1, is ∼0.2% of the quasar bolometric luminosity, which is comparable to the minimum value required for negative feedback based on simulation predictions. The dynamical timescale of the extended outflow is ∼1.7 Myr, consistent with the typical quasar lifetime in this era. [ABSTRACT FROM AUTHOR]

The extraplanar diffuse ionised gas (eDIG) is a key component for understanding the feedback processes that connect galactic discs and their halos. In this paper, we present the second study of the Bidimensional Exploration of the warm-Temperature Ionised Gas (BETIS) project, the aim of which is to explore the possible ionisation mechanisms and characteristics of the eDIG. We use a sample of eight edge-on galaxies observed with the Multi-Unit Spectroscopic Explorer (MUSE) integral field spectrograph (IFS) and apply the methodology developed in the first paper of the BETIS project for obtaining binned emission line maps. We find that the vertical and radial profiles of the [N II]/Hα, [S II]/Hα, [O III]/Hβ, and [O I]/Hα ratios depict a complex ionisation structure within galactic halos – which is influenced by the spatial distribution of H II regions across the galactic plane as observed from our line of sight–, with Lyman continuum photon leakage from OB associations constituting the main ionisation source. Moreover, the electron temperature and S+/S ionisation ratio also exhibit a dependency on the distribution of H II regions within the galactic discs. Our analysis excludes low-mass, hot, and evolved stars (HOLMES) as viable candidates for secondary ionisation sources to elucidate the unusual behaviour of the line ratios at greater distances from the galactic midplane. In contrast, we ascertain that shocks induced in the interstellar medium by star formation(SF)-related feedback mechanisms represent a promising secondary ionisation source of the eDIG. We present a suite of models integrating ionisation mechanisms arising from fast shocks and photoionisation associated with star formation. When applied to the classical Baldwin–Phillips–Terlevich (BPT) diagrams, these models reveal that the ionisation budget of the eDIG ranges from 20% to 50% across our sample, with local variations of up to 20% within individual galaxy halos. This contribution correlates with the presence of filaments and other structural components observed within galaxy halos. The presence of shocks is additionally supported by the observation of a high density of high [O I]/Hα ratios, which is characteristic of shock-compressed ionised gas, and is likely induced by feedback from regions of intense SF within the galactic disc. These results demonstrate consistency across all galaxies analysed in this sample. [ABSTRACT FROM AUTHOR]

To study the demographics of interstellar ices in the Central Molecular Zone (CMZ) of the Milky Way, we obtain near-infrared spectra of 109 red point sources using NASA IRTF/SpeX at Maunakea. We select the sample from near- and mid-infrared photometry, including 12 objects in the previous paper of this series, to ensure that these sources trace a large amount of absorption through clouds in each line of sight. We find that most of the sample (100 objects) show CO band-head absorption at 2.3 ÎĽ m, tagging them as red (super-) giants. Despite the photospheric signature, however, a fraction of the sample with L -band spectra (9/82 = 0.11) exhibit large H2O ice column densities (N > 2 Ă— 1018 cmâˆ'2), and six of them also reveal CH3OH ice absorption. As one of such objects is identified as a young stellar object (YSO) in our previous work, these ice-rich sight lines are likely associated with background stars in projection to an extended envelope of a YSO or a dense cloud core. The low frequency of such objects in the early stage of stellar evolution implies a low star-formation rate (≲0.02 M ⊙ yrâˆ'1), reinforcing the previous claim on the suppressed star-formation activity in the CMZ. Our data also indicate that the strong “shoulder” CO2 ice absorption at 15.4 ÎĽ m observed in YSO candidates in the previous paper arises from CH3OH-rich ice grains having a large CO2 concentration [ N (CO2)/ N (CH3OH) ≈ 1/3]. [ABSTRACT FROM AUTHOR]

This document is a correction to a paper titled "Determining star-formation rates in active galactic nuclei hosts via stellar population synthesis." The correction addresses an inconsistency in the value of |$H_0$| used in the analysis. The authors have now adopted a uniform value of |$H_0=73.0$| km s|$^{-1}$| Mpc|$^{-1}$| for both star-formation rates (SFR|$_\\star$| and SFR|$_{Gas}$|). As a result, some figures and the transformation equation have been updated. The conclusions of the paper remain unchanged. The document provides the corrected equations and figures for reference. [Extracted from the article]

JWST observations of galaxies at z ≳ 8 suggest that they are more luminous and clumpier than predicted by most models, prompting several proposals on the physics of star formation and feedback in the first galaxies. In this paper, we focus on the role of ultraviolet (UV) radiation in regulating star formation by performing a set of cosmological radiation hydrodynamics simulations of one galaxy at subparsec resolution with different radiative feedback models. We find that the suppression of cooling by far-UV (FUV) radiation (i.e., H2 dissociating radiation) from Population II stars is the main physical process triggering the formation of compact and massive star clusters and is responsible for the bursty star formation observed in metal-poor galaxies at z ≳ 10. Indeed, artificially suppressing FUV radiation leads to a less intense continuous mode of star formation distributed into numerous but low-mass open star clusters. Due to the intense FUV field, low-metallicity clouds remain warm (∼104 K) until they reach a relatively high density (≳103 cm−3), before becoming self-shielded and transitioning to a colder (∼100 K), partially molecular phase. As a result, star formation is delayed until the clouds accumulate enough mass to become gravitationally unstable. At this point, the clouds undergo rapid star formation, converting gas into stars with high efficiency. We therefore observe exceptionally bright galaxies (10 times brighter than for continuous star formation) and subsequent quenched "dead" galaxies that did not form stars for tens of Myr. [ABSTRACT FROM AUTHOR]

This paper investigates a mathematical model of a star formation system, including in-fall of gas from the local environment and out-flow of gas due to supernovae explosions and perturbations. In particular, the objective is to study how the variable density of interstellar components of the system namely atomic, molecular, and stellar components, interact in the star formation cycle. Under special parametric conditions, both limit cycle and stationary state behavior are observed. This indicates a stable star formation cycle in discrete episodes and an unstable star formation cycle converging to a stationary state. Observations of duty cycles under various parameters with varying intensity of supernovae shockwaves for dwarf galaxies, showed that the system adopts a self-regulatory oscillation state beyond a particular value. Analysis of giant galaxies showed decreased oscillatory periods for higher values. This is implied by the low production rate of supernovae in dwarf galaxies, increased production of cold gas, continuation of the cyclic behavior for a longer time. Stronger shockwaves increase the rate of dissipation of gases, resulting in shredding of mass, to get transferred into a precipitous lower mass. Star-forming rate (SFR) of high-mass star systems was found to vary against higher-order perturbations of supernovae shockwave but remained the same in the case of low-mass star systems. [ABSTRACT FROM AUTHOR]

The mere existence of multiple stellar generations in Milky Way globular clusters indicates that each generation was unable to stop star formation, that instead persisted unimpeded for several million years. This evidence argues for an extended stage of star formation within a forming globular cluster, during which stellar feedback was substantially ineffective and the nascent globular cluster was able to accrete processed gas from its surrounding, and efficiently convert it into successive stellar generations. It has been argued that such delayed feedback results from core collapse in most massive stars failing to trigger an energetic supernova explosion, but rather leading directly to black hole formation. Thus, globular clusters offer a concrete phenomenological example for the lack of feedback in young starbursts, an option that has been widely advocated to account for the unexpected abundance of ultraviolet-luminous galaxies at z = 9–16, as revealed by JWST observations. The paper is meant to attract attention to this opportunity for a synergic cooperation of globular cluster and high-redshift research. [ABSTRACT FROM AUTHOR]

Quasars have an important role in the studies of galaxy evolution and star formation. The rare close projection of two quasars in the sky allows us to study the environment and matter exchange around the foreground quasar ( Q S O f g ) and the background quasar ( Q S O b g ). This paper proposes a pipeline DPQP for quasar pair (QP) candidates' detection based on photometric images and the corresponding spectra. The pipeline consists of three main parts: a target source detector, a regressor, and a discriminator. In the first part, the target source detection network–YOLOv4 (TSD-YOLOv4) and the target source classification network (TSCNet) are used in sequence to detect quasars in SDSS photometric images. In the second part, a depth feature extraction network of quasar images (DE-QNet) is constructed to estimate the redshifts of quasars from photometric images. In the third part, a quasar pair score (Q-Score) metric is proposed based on the spectral analysis. The larger the Q-Score, the greater the possibility of two pairs being a quasar pair. The experimental results show that between redshift 1.0 and 4.0, the MAE of DE-QNet is 0.316, which is 16.1% lower than the existing method. Samples with | Δ z| < 0.15 account for 77.1% of the test dataset. A new table with 1025 QP candidates is provided by traversing 50,000 SDSS photometric images. [ABSTRACT FROM AUTHOR]

Observed breakBRD ("break bulges in red disks") galaxies are a nearby sample of face-on disk galaxies with particularly centrally concentrated star formation: they have red disks but recent star formation in their centers as measured by the D n 4000 spectral index. In Kopenhafer et al., a comparable population of breakBRD analogs was identified in the TNG simulation, in which the central concentration of star formation was found to reflect a central concentration of dense, star-forming gas caused by a lack of dense gas in the galaxy outskirts. In this paper, we examine the circumgalactic medium of the central breakBRD analogs to determine if the extended halo gas also shows differences from that around comparison galaxies with comparable stellar mass. We examine the circumgalactic medium gas mass, specific angular momentum, and metallicity in these galaxy populations. We find less gas in the circumgalactic medium of breakBRD galaxies, and that the breakBRD circumgalactic medium is slightly more concentrated than that of comparable M * galaxies. In addition, we find that the angular momentum in the circumgalactic medium of breakBRD galaxies tends to be low for their stellar mass, and shows more misalignment to the angular momentum vector of the stellar disk. Finally, we find that the circumgalactic medium metallicity of breakBRD galaxies tends to be high for their stellar mass. Together with their low star formation rate, we argue that these circumgalactic medium properties indicate a small amount of disk feeding concentrated in the central regions and a lack of low-metallicity gas accretion from the intergalactic medium. [ABSTRACT FROM AUTHOR]

The paper is devoted to the analysis of the observation results with the single-mirror radio telescope RT-22 (PRAO, LPI) in the water vapor maser line at 22 GHz in the direction of dust clumps from the ATLASGAL and Bolocam large-scale blind surveys in the millimeter continuum. The aim of this paper is to search for masers in the water vapor line in previously unexplored sources and to study the variability of known masers. Observations of 140 sources resulted in the detection of maser emission at 22 GHz in six sources, and in four sources (ATLASGAL 016.987+00.981, 017.216+00.821, 018.701–00.229, and Bolocam 081.174–00.100) masers were detected for the first time. In two sources (ATLASGAL 034.195–0.592 and Bolocam 081.174–0.1), the water vapor line masers showed significant variability during the 8-month observation and follow-up program. Comparison of RT-22 observational data with archival data from the GBT‑100 telescope (US National Radio Astronomy Observatory) showed that 9 out of 140 sources show a significant change in the radiation flux density of masers: two sources changed from the category of masers with low brightness ( Jy) to the category bright (more than 10 Jy), and in seven relatively bright earlier (more than 3 Jy) masers, no radiation was detected. Significant changes in the characteristics of the maser emission may indicate changes in the environmental conditions in which the maser emission was produced, which is of interest for further study of maser-related processes. [ABSTRACT FROM AUTHOR]

We present JWST and Atacama Large Millimeter/submillimeter Array (ALMA) imaging for the lensing system SPT0418−47, which includes a strongly lensed, dusty, star-forming galaxy at redshift z = 4.225 and an associated multiply imaged companion. The JWST NIRCam and MIRI imaging observations presented in this paper were acquired as part of the Early Release Science program Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star formation (TEMPLATES). This data set provides robust mutiwavelength detections of stellar light in both the main (SPT0418A) and companion (SPT0418B) galaxies, while the ALMA detection of [C ii ] emission confirms that SPT0418B lies at the same redshift as SPT0418A. We infer that the projected physical separation of the two galaxies is 4.42 ± 0.05 kpc. We derive total magnifications of μ = 29 ± 1 and μ = 4.1 ± 0.7 for SPT0418A and SPT0418B, respectively. We use both prospector and cigale to derive stellar masses. We find that SPT0418A has a stellar mass of M * = 3.4 − 0.6 + 1.1 × 10 10 M ⊙ from prospector or M * = 1.5 ± 0.3 × 1010 M ⊙ from cigale. The stellar mass ratio of SPT0418A and SPT0418B is roughly between 4 and 7 ( 4.2 − 1.6 + 1.9 for prospector and 7.5 ± 3.7 for cigale). We see evidence of extended structure associated with SPT0418A that is suggestive of a tidal feature. These features, along with the close projected proximity, imply that the system is interacting. Interestingly, the star formation rates and stellar masses of both galaxies are consistent with the main sequence of star-forming galaxies at this epoch, indicating that this ongoing interaction has not noticeably elevated the star formation levels. [ABSTRACT FROM AUTHOR]

Far-infrared and submillimeter observations have established the fundamental role of dust-obscured star formation in the assembly of stellar mass over the past ∼12 billion years. At z = 2–4, the so-called "cosmic noon", the bulk of star formation is enshrouded in dust, and dusty star-forming galaxies (DSFGs) contain ∼ 50 % of the total stellar mass density. Star formation occurs in dense molecular clouds, and is regulated by a complex interplay between all the ISM components that contribute to the energy budget of a galaxy: gas, dust, cosmic rays, interstellar electromagnetic fields, gravitational field, and dark matter. Molecular gas is the actual link between star-forming gas and its complex environment: much of what we know about star formation comes from observations of molecular line emissions. They provide by far the richest information about the star formation process. However, their interpretation requires complex modeling of the astrochemical networks which regulate molecular formation and establish molecular abundances in a cloud, and a modeling of the physical conditions of the gas in which molecular energy levels become populated. This paper critically reviews the main astrochemical parameters needed to obtain predictions about molecular signals in DSFGs. Molecular lines can be very bright compared to the continuum emission, but radiative transfer models are required to properly interpret the observed brightness. We review the current knowledge and the open questions about the interstellar medium of DSFGs, outlining the key role of molecular gas as a tracer and shaper of the star formation process. [ABSTRACT FROM AUTHOR]

We compare the molecular cloud properties in subgalactic regions of two galaxies, barred spiral NGC 1313, which is forming many massive clusters, and flocculent spiral NGC 7793, which is forming significantly fewer massive clusters despite having a similar star formation rate to NGC 1313. We find that there are larger variations in cloud properties between different regions within each galaxy than there are between the galaxies on a global scale, especially for NGC 1313. There are higher masses, line widths, pressures, and virial parameters in the arms of NGC 1313 and the center of NGC 7793 than in the interarm and outer regions of the galaxies. The massive cluster formation of NGC 1313 may be driven by its greater variation in environment, allowing more clouds with the necessary conditions to emerge, although no one parameter seems primarily responsible for the difference in star formation. Meanwhile NGC 7793 has clouds that are as massive and have as much kinetic energy as the clouds in the arms of NGC 1313, but have densities and pressures more similar to those in the interarm regions and so are less inclined to collapse and form stars. The cloud properties in NGC 1313 and NGC 7793 suggest that spiral arms, bars, interarm regions, and flocculent spirals each represent distinct environments with regard to molecular cloud populations. We see surprisingly little difference in surface density between the regions, suggesting that the differences in surface densities frequently seen between arm and interarm regions in lower-resolution studies are indicative of the sparsity of molecular clouds, rather than differences in their true surface density. [ABSTRACT FROM AUTHOR]

Serpens molecular cloud is one of the most active sites of ongoing star formation at a distance of about 300 pc, and hence, is very well-suited for studies of young low-mass stars and sub-stellar objects. In this paper, for the Serpens star-forming region, we found potential members of the Young Stellar Objects (YSOs) population from the Gaia DR3 data and study their kinematics and distribution. We compiled a catalog of 656 YSOs from available catalogs ranging from X-ray to the infrared. We use this as a reference set and cross-match it to find 87 Gaia DR3 member stars to produce a control sample with revised parameters. We queried the DR3 catalog with these parameters and found 1196 stars. We then applied three different density-based machine learning algorithms (DBSCAN, OPTICS and HDBSCAN) to this sample and found potential YSOs. The three clustering algorithms identified a common set of 822 YSO members from Gaia DR3 in this region. We also classified these objects using 2MASS and WISE data to study their distribution and the progress of star-formation in Serpens. [ABSTRACT FROM AUTHOR]

Understanding how stars form, evolve, and impact molecular clouds is key to understanding why star formation is such an inefficient process globally. In this paper, we use the infrared bright fraction, |$f_\text{IRB}$| (the fraction of a given molecular cloud that appears bright against the 8 |$\mu$| m Milky Way background) as a proxy for time evolution to test how cloud properties change as star formation evolves. We apply this metric to 12 000 high-mass star-forming molecular clouds we identify using the Herschel –Hi-GAL survey between |$|\ell |{\lt }70^{\circ }$| on the Milky Way plane. We find clouds are not static while forming stars. Instead, molecular clouds continuously gain mass while star formation progresses. By performing principal component analysis on the cloud properties, we find that they evolve down two paths distinguished by their mass gain. Most clouds (80 per cent) gain four times more mass as a function of |$f_\text{IRB}$|⁠. The remaining 20 per cent experience an extreme period of growth, growing in mass by a factor of 150 on average and during this period, they initially gain mass fast enough to outpace their star formation. For all clouds, it is only after half their area becomes star forming that mass-loss occurs. We expect stellar feedback and potentially galactic shear is responsible. By analysing cloud positions, we suggest that the rate of mass growth may be linked to the larger galactic environment. Altogether, these results have strong implications on how we assess star-forming ability on cloud scales when assuming molecular cloud masses are fixed in time. [ABSTRACT FROM AUTHOR]

It is well known that departure from sphericity in the geometry of primordial dark matter haloes modifies their mass function. The ellipsoidal collapse model yields a better agreement with simulations of hierarchical clustering than the original spherical model. In this paper, we examine the same issue in the context of star formation by studying the impact of non-sphericity of density perturbations in a gravoturbulent medium on the prestellar core mass function (CMF). An important question, notably, is to find out how ellipsoidal, instead of spherical, initial density fluctuations modify both the high-mass and low-mass tails of the CMF. Our study shows that triaxial density fluctuations indeed depart from a purely spherical form but the deformation (prolateness and ellipticity) remains modest, suggesting that the usual hypothesis of spherical collapse in existing theories of the IMF is reasonable. We find that, as in the cosmological case, the departure from sphericity increases the collapse barrier, stabilizing the prestellar cores. The striking difference between the stellar case and the cosmological one for the ellipsoidal collapse model is that, although in both cases the less dense structures are the most deformed, they correspond to small scales, thus low-mass haloes in cosmology but to large scales, thus large mass cores in star formation. As a result, the high-mass range of the CMF is the most affected by the ellipsoidal collapse, resulting in a slightly less steep slope than the one predicted with the spherical hypothesis and a peak slightly shifted towards lower masses. [ABSTRACT FROM AUTHOR]

Galactic double white dwarfs (DWDs) are predominant sources of gravitational waves in the millihertz frequencies accessible to space-borne gravitational wave (GW) detectors. With advances in multimessenger astronomy, an increasing number of DWD systems will be discovered through both electromagnetic (EM) and GW observations. In this paper, we simulated two populations of DWDs originating from different star formation histories (hereafter referred to as Model 1 and Model 2) using the binary population synthesis method. We predicted the number of DWDs in our Galaxy detectable by TianQin and Laser Interferometer Space Antenna (LISA) individually, as well as through their joint observation. In addition, we performed an analysis to evaluate the accuracy of the parameter estimation using the Fisher information matrix. Furthermore, we predicted the number of detached eclipsing DWDs detectable by Gaia and the Vera C. Rubin Observatory (VRO). Our study found that over the nominal mission durations, TianQin, LISA, and their joint observation can detect at least 5000 and potentially several tens of thousands of DWDs with signal-to-noise ratios greater than 7. Gaia and VRO are expected to detect at least several dozen and up to several hundred eclipsing DWDs with orbital periods less than 30 h. We also found that several dozen eclipsing DWDs can be detected jointly through EM and GW observations. [ABSTRACT FROM AUTHOR]

This paper presents near-infrared spectropolarimetric and velocimetric observations of the young planet-hosting T Tauri star PDS 70, collected with SPIRou at the 3.6-m Canada–France–Hawaii Telescope from 2020 to 2024. Clear Zeeman signatures from magnetic fields at the surface of PDS 70 are detected in our data set of 40 circularly polarized spectra. Longitudinal fields inferred from Zeeman signatures, ranging from |$-116$| to 176 G, are modulated on a time-scale of |$3.008\pm 0.006$| d, confirming that this is the rotation period of PDS 70. Applying Zeeman–Doppler imaging to subsets of unpolarized and circularly polarized line profiles, we show that PDS 70 hosts low-contrast brightness spots and a large-scale magnetic field in its photosphere, featuring in particular a dipole component of strength 200–420 G that evolves on a time-scale of months. From the broadening of spectral lines, we also infer that PDS 70 hosts a small-scale field of |$2.51\pm 0.12$| kG. Radial velocities derived from unpolarized line profiles are rotationally modulated as well, and exhibit additional longer term chromatic variability, most likely attributable to magnetic activity rather than to a close-in giant planet (with a 3 |$\sigma$| upper limit on its minimum mass of |$\simeq$| 4 at a distance of |$\simeq$| 0.2 au). We finally confirm that accretion occurs at the surface of PDS 70, generating modulated redshifted absorption in the 1083.3-nm He  i triplet, and show that the large-scale magnetic field, often strong enough to disrupt the inner accretion disc up to the corotation radius, weakens as the star gets fainter and redder (as in 2022), suggesting that dust from the disc more easily penetrates the stellar magnetosphere in such phases. [ABSTRACT FROM AUTHOR]

We present James Webb Space Telescope MIRI data of the inner ∼3 × 2 kpc2 of the galaxy IC 5063, in which the jets of a supermassive black hole interact with the gaseous disk they are crossing. Jet-driven outflows were known to be initiated along or near the jet path and to modify the stability of molecular clouds, possibly altering their star formation properties. The MIRI data, of unprecedented resolution and sensitivity in the infrared, now reveal that there are more than 10 discrete regions with outflows, nearly doubling the number of such known regions. Outflows exist near the radio lobes, at the nucleus, in a biconical structure perpendicular to the jet, and in a bubble moving against the disk. In some of them, velocities above escape velocity are observed. Stratification is also observed, with higher ionization or excitation gas attaining higher velocities. More outflows and bow shocks, found further away from the nucleus than the radio lobes, in regions without significant radio emission, reveal the existence of past or weak radio jets that interacted with the interstellar medium. The coincidence of the bow shocks with the optical extended emission line region (EELR) suggests that the jets also contributed to the gas ionization. Maps of the H2 gas excitation temperature, T ex, indicate that the molecular gas is most excited in regions with radio emission. There, T ex is >100 K higher than in the EELR interior. We argue that a combination of jet-related shocks and cosmic rays is likely responsible for this excess molecular gas excitation. [ABSTRACT FROM AUTHOR]

This paper presents a 610 MHz radio survey covering 1.94 deg |$^2$| around the North Ecliptic Pole (NEP), which includes parts of the |${\it AKARI}$| (ADF-N) and Euclid, Deep Fields North. The median 5 |$\sigma$| sensitivity is 28  |$\mu$| Jy beam |$^{-1}$|⁠ , reaching as low as 19  |$\mu$| Jy beam |$^{-1}$|⁠ , with a synthesized beam of 3.6 arcsec |$\times$| 4.1  arcsec. The catalogue contains 1675 radio components, with 339 grouped into multicomponent sources and 284 'isolated' components likely part of double radio sources. Imaging, cataloguing, and source identification are presented, along with preliminary scientific results. From a non-statistical sub-set of 169 objects with multiwavelength AKARI and other detections, luminous infrared galaxies (LIRGs) represent 66 |${{\ \rm per\ cent}}$| of the sample, ultra-luminous infrared galaxies (ULIRGs) 4 |${{\ \rm per\ cent}}$|⁠ , and sources with L |$_{IR}$| <  10 |$^{11}$|   |$\mathrm{ L}_{\odot }\,$| 30 |${{\ \rm per\ cent}}$|⁠. In total, 56 |${{\ \rm per\ cent}}$| of sources show some AGN presence, though only seven are AGN-dominated. ULIRGs require three times higher AGN contribution to produce high-quality SED fits compared to lower luminosity galaxies, and AGN presence increases with AGN fraction. The PAH mass fraction is not significant, although ULIRGs have about half the PAH strength of lower IR-luminosity galaxies. Higher luminosity galaxies show gas and stellar masses an order of magnitude larger, suggesting higher star formation rates. For LIRGs, AGN presence increases with redshift, indicating that part of the total luminosity could be contributed by AGN activity rather than star formation. Simple cross-matching revealed 13 ROSAT QSOs, 45 X-ray sources, and 61 sub-mm galaxies coincident with GMRT radio sources. [ABSTRACT FROM AUTHOR]

We use the Atacama Large sub/Millimetre Array (ALMA) to efficiently observe spectral lines across Bands 3, 4, 5, 6, 7, and 8 at high-resolution (0.5–0.1 arcsec) for 16 bright southern Herschel sources at |$1.5 \lt z \lt 4.2$|⁠. With only six and a half hours of observations, we reveal 66 spectral lines in 17 galaxies. These observations detect emission from CO (3−2) to CO(18−17), as well as atomic ([C  i ](1−0), (2−1), [O  i ] 145 |$\mu$| m and [N  ii ] 205 |$\mu$| m) lines. Additional molecular lines are seen in emission (⁠|${\rm H_2O}$| and |${\rm H_2O^+}$|⁠) and absorption (OH |$^+$| and CH |$^+$|⁠). The morphologies based on dust continuum ranges from extended sources to strong lensed galaxies with magnifications between 2 and 30. CO line transitions indicate a diverse set of excitation conditions with a fraction of the sources (⁠|$\sim 35$|  per cent) showcasing dense, warm gas. The resolved gas to star formation surface densities vary strongly per source, and suggest that the observed diversity of dusty star-forming galaxies could be a combination of lensed, compact dusty starbursts and extended, potentially merging galaxies. The predicted gas depletion time-scales are consistent with 100 Myr to 1 Gyr, but require efficient fuelling from the extended gas reservoirs onto the more central starbursts, in line with the Doppler-shifted absorption lines that indicate inflowing gas for two out of six sources. This pilot paper explores a successful new method of observing spectral lines in large samples of galaxies, supports future studies of larger samples, and finds that the efficiency of this new observational method will be further improved with the planned ALMA Wideband Sensitivity Upgrade. [ABSTRACT FROM AUTHOR]

High‐resolution hydrodynamical simulations are presented to follow the gravitational collapse of a uniform turbulent clump, upon which a purely radial compressive velocity pulse is activated in the midst of the evolution of the clump, when its turbulent state has been fully developed. The shape of the velocity pulse is determined basically by two free parameters: the velocity V0 and the initial radial position r0. In the present paper, models are considered in which the velocity V0 takes the values 2, 5, 10, 20, and 50 times the speed of sound of the clump c0, while r0 is fixed for all the models. The collapse of the model with 2 c0 goes faster as a consequence of the velocity pulse, while the cluster formed in the central region of the isolated clump mainly stays the same. In the models with greater velocity V0, the evolution of the isolated clump has significantly changed, so a dense shell of gas forms around r0 and moves radially inward. The radial profile of the density and velocity and the mass contained in the dense shell of gas are calculated, and it is found that (a) the higher the velocity V0, the less mass is contained in the shell, and (b) there is a critical velocity of the pulse, around 10 c0, such that, for shock models with a lower velocity, there will be a well‐defined dense central region in the shocked clump surrounded by the shell. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of nonisothermal processes on the evolution of the cloud's envelope around a newborn protostar. For this purpose, we study the evolution of a spherical cloud harboring a central hydrostatic newborn protostar. This model includes thermal effects due to heating of the cosmic rays and cooling of the gas and gas–dust energy transfer. We have ignored the effects of the magnetic field and rotation. The semianalytical Adomian decomposition method (ADM) is used to solve the system of nonlinear dynamical equations for different initial conditions. In this paper, the ADM allows us to follow the time evolution of the cloud's envelope and its mass accretion rate onto the newborn protostar. We find that the mass accretion rates of the envelope are increasing functions of time and highly depend on the choice of initial conditions. Moreover, we find that the nonisothermal processes affect the evolution of the mass accretion rates compared with the isothermal processes for different initial conditions. [ABSTRACT FROM AUTHOR]