Search

We use medium-resolution JWST/NIRSpec observations from the Cosmic Evolution Early Release Science Survey to place the first constraints on dust attenuation and star formation based on Paschen lines for a sizable sample of 63 galaxies at redshifts z = 1.0-3.1. Our analysis indicates strong correlations between the Balmer decrement, H alpha/H beta, and line ratios that include Paschen lines (i.e., Pa alpha/H beta, Pa beta/H beta, and the Paschen decrement, Pa alpha/Pa beta), suggesting that the former is sensitive to the overall dust obscuration toward H ii regions in high-redshift galaxies. The line ratios are used to derive nebular reddening, E(B - V)(neb), and star formation rates (SFRs). There is marginal evidence that the SFRs deduced from Paschen lines may exceed by approximate to 25% those derived from Balmer lines alone, suggesting the presence of star formation that is optically thick in Balmer lines, though deeper observations are needed to confirm this result. Using the Paschen-line constraints on the bolometric SFRs, we reevaluate the relationship between dust obscuration and UV spectral slope, and find a reddening of the UV continuum that, on average, follows the SMC extinction curve. This analysis highlights the need for deeper spectroscopy of more representative samples to evaluate nebular dust attenuation and bolometric SFRs in high-redshift galaxies, and their relationship to the reddening of the UV continuum.

© 2011 IOP Publishing Ltd and SISSA. We would like to thank the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the Marie Curie program, by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the Academy of Finland, by the YIP of the Helmholtz Gemeinschaft, by the DFG Cluster of Excellence "Origin and Structure of the Universe", and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0., We report the results of the observation of the nearly satellite galaxy Segue 1 performed by the MAGIC-I ground-based gamma-ray telescope between November 2008 and March 2009 for a total of 43.2 hours. No significant gamma-ray emission was found above the bmkground. Differential upper limits on the grimma-ray flux are derived assuming various power-law slopes for the possible emission spectrum. Integral upper limits are also calculated for several power-law spectra and for different energy thresholds. The values are of the order of 10(-11) ph cm(-2) s(-1) above 100 GeV and 10(-12) ph cm(-2) s(-1) above 200 GeV. Segue 1 is currently considered one of the most interesting targets for indirect dark matter searches. In these terms, the upper limits have been also interpreted in the context of annihilating dark matter particles. For such purpose, we performed a grid scan over a reasonable portion of the parameter space for the minimal SuperGravity model and computed the flux upper limit for each point separately, taking fully into account the peculiar spectral features of each model. We found that in order to match the experimental upper limits with the model predictions, a minimum flux boost of 10(3) is required, and that the upper limits are quite dependent on the shape of the gamma-ray energy spectrum predicted by each specific model. Finally we compared the upper limits with the predictions of some dark matter models able to explain the PAMELA rise in the positron ratio, finding that Segue 1 data are in tension with the dark matter explanation of the PAMELA spectrum in the case of a dark matter candidate annihilating into tau(+)tau(-). A complete exclusion however is not possible due to the uncertainties in the Segue 1 astrophysical factor., German BMBF, German MPG, Italian INFN, Swiss National Fund SNF, Spanish MICINN, Marie Curie program, Spanish Consolider-Ingenio 2010 programme, Bulgarian NSF, Academy of Finland, YIP of the Helmholtz Gemeinschaft, DFG, Polish MNiSzW, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

We present visual classifications of merger-induced tidal disturbances in 143 M-* similar to 10(11)M(circle dot) post-starburst galaxies at z similar to 0.7 identified in the. SQuIGG (L) over right arrowE Sample. This sample spectroscopically selects galaxies from the Sloan Digital Sky Survey that have stopped their primary epoch of star formation within the past similar to 500 Myr. Visual classifications are performed on Hyper Suprime-Cam imaging. We compare to a control sample of mass- and redshift-matched star-forming and quiescent galaxies from the Large Early Galaxy Census and find that post-starburst galaxies are more likely to be classified as disturbed than either category. This corresponds to a factor of 3.6(-1.3)(+2.9) times the disturbance rate of older quiescent galaxies and 2.1(-.73)(+1.9) times the disturbance rate of star-forming galaxies. Assuming tidal features persist for less than or similar to 500 Myr, this suggests merging is coincident with quenching in a significant fraction of these post-starbursts. Galaxies with tidal disturbances are younger on average than undisturbed post-starburst galaxies in our sample, suggesting tidal features from a major merger may have faded over time. This may be exacerbated by the fact that, on average, the undisturbed subset is fainter, rendering low- surface-brightness tidal features harder to identify. However, the presence of 10 young (less than or similar to 150 Myr since quenching) undisturbed galaxies suggests that major mergers are not the only fast physical mechanism that shut down the primary epoch of star formation in massive galaxies at intermediate redshift.

We present a pilot, untargeted extragalactic carbon monoxide (CO) emission-line survey using ALMACAL, a project utilizing ALMA calibration data for scientific purposes. In 33 deep (T-exp' > 40 min) ALMACAL fields, we report six CO emission-line detections above S/N > 4, one-third confirmed by MUSE observations. With this pilot survey, we probe a cosmologically significant volume of similar to 10(5) cMpc(3), widely distributed over many pointings in the southern sky, making the survey largely insusceptible to the effects of cosmic variance. We derive the redshift probability of the CO detections using probability functions from the SHARK semi-analytical model of galaxy formation. By assuming typical CO excitations for the detections, we put constraints on the cosmic molecular gas mass density evolution over the redshift range 0 < z < 1.5. The results of our pilot survey are consistent with the findings of other untargeted emission-line surveys and the theoretical model predictions and currently cannot rule out a non-evolving molecular gas mass density. Our study demonstrates the potential of using ALMA calibrator fields as a multi-sightline untargeted CO emission-line survey. Applying this approach to the full ALMACAL database will provide an accurate, free of cosmic variance, measurement of the molecular luminosity function as a function of redshift.

Cosmic dust is an essential component shaping both the evolution of galaxies and their observational signatures. How quickly dust builds up in the early Universe remains an open question that requires deep observations at (sub-)millimetre wavelengths to resolve. Here, we use Atacama Large Millimeter Array observations of 45 galaxies from the Reionization Era Bright Emission Line Survey (REBELS) and its pilot programs, designed to target [C II] and dust emission in UV-selected galaxies at z similar to 7, to investigate the dust content of high-redshift galaxies through a stacking analysis. We find that the typical fraction of obscured star formation integral(obs) = SFRIR/SFRUV+IR depends on stellar mass, similar to what is observed at lower redshift, and ranges from f(obs) approximate to 0.3 - 0.6 for galaxies with log(10)(M*/M circle dot) = 9.4-10.4. We further adopt the z similar to 7 stellar mass function from the literature to extract the obscured cosmic star formation rate density (SFRD) from the REBELS survey. Our results suggest only a modest decrease in the SFRD between 3 less than or similar to z less than or similar to 7, with dust-obscured star formation still contributing similar to 30 per cent at z similar to 7. While we extensively discuss potential caveats, our analysis highlights the continued importance of dust-obscured star formation even well into the epoch of reionization.

© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. We are grateful with the anonymous referee for improving the manuscript contents. NEB and JZ acknowledge funding support from the Spanish Programa Nacional de Astronomía y Astrofísica under grant AYA2006-02358. NEB acknowledges support from Fac. CC. Físicas, Universidad Complutense de Madrid (UCM), and from Coordinación de Astrofísica, Instituto Nacional de Astrofísica ptica y Electrónica (INAOE). PGPG acknowledges funding support from the Spanish Government under grant PGC2018-093499-B-I00. LRM acknowledges support from grant PRIN MIUR 2017-20173ML3WW_001 and funding from the Universita degli studi di Padova - Dipartimento di Fisica e Astronomia 'G. Galilei'. This work has made use of the rainbow Cosmological Surveys Database, which is operated by the Centro de Astrobiología (CAB/CSIC-INTA)., We study in detail the properties of the stellar populations of 111 massive [log (M-*/M-circle dot) >= 10] dusty [far-infrared (FIR)-selected] starburst (SFR/SFRMS > 2) galaxies at 0.7 < z < 1.2. For that purpose, we use self-consistent methods that analyse the UV-to-FIR broad-band observations in terms of the stellar light and dust re-emission with energy-balance techniques. We find that the emission of our starburst galaxies can be interpreted as a recent star formation episode superimposed on a more evolved stellar population. On average, the burst age is similar to 80 Myr and its attenuation similar to 2.4 mag. Assuming our starburst galaxies at half their lifetimes, we infer a duration of the starburst phase of similar to 160 Myr. The median stellar mass and star formation rate (SFR) are log (M-*/M-circle dot) similar to 10.6 and similar to 220 M(circle dot)yr(-1). Assuming this SFR and the inferred duration of the starburst phase, the stellar mass added during this phase corresponds to similar to 40 per cent the median stellar mass of our sample. The young-population age determines the position of our galaxies in the M-*-SFR plane. Galaxies located at the largest distances of the MS present shorter young-population ages. The properties of the underlying stellar population cannot be constrained accurately with our broad-band data. We also discuss the impact of including the FIR data and energy-balance techniques in the analysis of the properties of the stellar populations in starburst galaxies., Ministerio de Ciencia e Innovación (MICINN), Universita degli studi di Padova - Dipartimento di Fisica e Astronomia 'G. Galilei', Facultad Ciencias Físicas, Universidad Complutense de Madrid (UCM), Coordinación de Astrofísica, Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE), Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

One of the most prominent features of galaxy clusters is the presence of a dominant population of massive ellipticals in their cores. Stellar archaeology suggests that these gigantic beasts assembled most of their stars in the early Universe via starbursts. However, the role of dense environments and their detailed physical mechanisms in triggering starburst activities remain unknown. Here we report spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO J & x2004;=& x2004;3-2 emission line, with a resolution of about 2.5 kpc, toward a forming galaxy cluster core with starburst galaxies at z & x2004;=& x2004;2.51. In contrast to starburst galaxies in the field often associated with galaxy mergers or highly turbulent gaseous disks, our observations show that the two starbursts in the cluster exhibit dynamically cold (rotation-dominated) gas-rich disks. Their gas disks have extremely low velocity dispersion (sigma(0)& x2004;similar to & x2004;20-30 km s(-1)), which is three times lower than their field counterparts at similar redshifts. The high gas fraction and suppressed velocity dispersion yield gravitationally unstable gas disks, which enables highly efficient star formation. The suppressed velocity dispersion, likely induced by the accretion of corotating and coplanar cold gas, might serve as an essential avenue to trigger starbursts in massive halos at high redshifts.

We report 18 dust continuum detections (>= 3.3 sigma) at similar to 88 and 158 mu m out of 49 ultraviolet (UV)-bright galaxies (M-UV < -21.3 mag) at z > 6.5, observed by the Cycle-7 Atacama Large Millimeter/submillimeter Array (ALMA) Large Program, Reionization-Era Bright Emission Line Survey (REBELS) and its pilot programs. This has more than tripled the number of dust continuum detections known at z > 6.5. Out of these 18 detections, 12 are reported for the first time as part of REBELS. In addition, 15 of the dust continuum detected galaxies also show a [C II](158 mu m) emission line, providing us with accurate redshifts. We anticipate more line emission detections from six targets (including three continuum detected targets) where observations are still ongoing. We estimate that all of the sources have an infrared (IR) luminosity (L IR) in a range of 3-8 x10(11) L-circle dot. except for one with L-IR = 1.5(-0.5)(+0.8) x10(12) L-circle dot. Their fraction of obscured star formation is significant at greater than or similar to 50 per cent, despite being UV-selected galaxies. Some of the dust continuum detected galaxies show spatial offsets (similar to 0.5-1.5 arcsec) between the rest-UV and far-IR emission peaks. These separations could imply spatially decoupled phases of obscured and unobscured star formation, but a higher spatial resolution observation is required to confirm this. REBELS offers the best available statistical constraints on obscured star formation in UV-luminous galaxies at z > 6.5.

We present an ALMA-Herschel joint analysis of sources detected by the ALMA Lensing Cluster Survey (ALCS) at 1.15 mm. Herschel/PACS and SPIRE data at 100-500 mu m are deblended for 180 ALMA sources in 33 lensing cluster fields that are detected either securely (141 sources; in our main sample) or tentatively at S/N >= 4 with cross-matched HST/Spitzer counterparts, down to a delensed 1.15 mm flux density of similar to 0.02 mJy. We performed far-infrared spectral energy distribution modeling and derived the physical properties of dusty star formation for 125 sources (109 independently) that are detected at >2 sigma in at least one Herschel band. A total of 27 secure ALCS sources are not detected in any Herschel bands, including 17 optical/near-IR-dark sources that likely reside at z = 4.2 +/- 1.2. The 16th, 50th, and 84th percentiles of the redshift distribution are 1.15, 2.08, and 3.59, respectively, for ALCS sources in the main sample, suggesting an increasing fraction of z similar or equal to 1 - 2 galaxies among fainter millimeter sources (f(1150) similar to 0.1 mJy). With a median lensing magnification factor of mu = 2.6(-0.8)(+2.6), ALCS sources in the main sample exhibit a median intrinsic star formation rate of 94(-54)(+84) M-circle dot yr(-1), lower than that of conventional submillimeter galaxies at similar redshifts by a factor of similar to 3. Our study suggests weak or no redshift evolution of dust temperature with L-IR < 10(12) L-circle dot galaxies within our sample at z similar or equal to 0 - 2. At L-IR > 10(12) L-circle dot, the dust temperatures show no evolution across z similar or equal to 1-4 while being lower than those in the local universe. For the highest-redshift source in our sample (z = 6.07), we can rule out an extreme dust temperature (>80 K) that was reported for MACS0416 Y1 at z = 8.31.

We present structural measurements of 145 spectroscopically selected intermediate-redshift (z similar to 0.7), massive (M-star similar to 10(11) M (circle dot)) post-starburst galaxies from the SQuIGG (L) over right arrowE i-band imaging. This deep imaging allows us to probe the sizes and structures of these galaxies, which we compare to a control sample of star-forming and quiescent galaxies drawn from the LEGA-C Survey. We find that post-starburst galaxies systematically lie similar to 0.1 dex below the quiescent mass-size (half-light radius) relation, with a scatter of similar to 0.2 dex. This finding is bolstered by nonparametric measures, such as the Gini coefficient and the concentration, which also reveal these galaxies to have more compact light profiles than both quiescent and star-forming populations at similar mass and redshift. The sizes of post-starburst galaxies show either negative or no correlation with the time since quenching, such that more recently quenched galaxies are larger or similarly sized. This empirical finding disfavors the formation of post-starburst galaxies via a purely central burst of star formation that simultaneously shrinks the galaxy and shuts off star formation. We show that the central densities of post-starburst and quiescent galaxies at this epoch are very similar, in contrast with their effective radii. The structural properties of z similar to 0.7 post-starburst galaxies match those of quiescent galaxies that formed in the early universe, suggesting that rapid quenching in the present epoch is driven by a similar mechanism to the one at high redshift.

Compact star formation appears to be generally common in dusty star-forming galaxies (SFGs). However, its role in the framework set by the scaling relations in galaxy evolution remains to be understood. In this work we follow up on the galaxy sample from the GOODS-ALMA 2.0 survey, an ALMA blind survey at 1.1 mm covering a continuous area of 72.42 arcmin(2) using two array configurations. We derived physical properties, such as star formation rates, gas fractions, depletion timescales, and dust temperatures for the galaxy sample built from the survey. There exists a subset of galaxies that exhibit starburst-like short depletion timescales, but they are located within the scatter of the so-called main sequence of SFGs. These are dubbed starbursts in the main sequence and display the most compact star formation and they are characterized by the shortest depletion timescales, lowest gas fractions, and highest dust temperatures of the galaxy sample, compared to typical SFGs at the same stellar mass and redshift. They are also very massive, accounting for similar to 60% of the most massive galaxies in the sample (log(M-*/M-circle dot) > 11.0). We find trends between the areas of the ongoing star formation regions and the derived physical properties for the sample, unveiling the role of compact star formation as a physical driver of these properties. Starbursts in the main sequence appear to be the extreme cases of these trends. We discuss possible scenarios of galaxy evolution to explain the results drawn from our galaxy sample. Our findings suggest that the star formation rate is sustained in SFGs by gas and star formation compression, keeping them within the main sequence even when their gas fractions are low and they are presumably on the way to quiescence.

We present an analysis of the chemical abundance properties of approximate to 650 star-forming galaxies at z approximate to 0.6-1.8. Using integral-field observations from the K-band multi-object spectrograph (KMOS), we quantify the [N II]/H alpha emission-line ratio, a proxy for the gas-phase oxygen abundance within the interstellar medium. We define the stellar mass-metallicity relation at z approximate to 0.6-1.0 and z approximate to 1.2-1.8 and analyse the correlation between the scatter in the relation and fundamental galaxy properties (e.g. H alpha star formation rate, H alpha specific star formation rate, rotation dominance, stellar continuum half-light radius, and Hubble-type morphology). We find that for a given stellar mass, more highly star-forming, larger, and irregular galaxies have lower gas-phase metallicities, which may be attributable to their lower surface mass densities and the higher gas fractions of irregular systems. We measure the radial dependence of gas-phase metallicity in the galaxies, establishing a median, beam smearing corrected, metallicity gradient of Delta Z/Delta R = 0.002 +/- 0.004 dex kpc(-1), indicating on average there is no significant dependence on radius. The metallicity gradient of a galaxy is independent of its rest-frame optical morphology, whilst correlating with its stellar mass and specific star formation rate, in agreement with an inside-out model of galaxy evolution, as well as its rotation dominance. We quantify the evolution of metallicity gradients, comparing the distribution of Delta Z/Delta R in our sample with numerical simulations and observations at z approximate to 0-3. Galaxies in our sample exhibit flatter metallicity gradients than local star-forming galaxies, in agreement with numerical models in which stellar feedback plays a crucial role redistributing metals.

We present the third and final data release of the Large Early Galaxy Astrophysics Census (LEGA-C), an ESO/Very Large Telescope public spectroscopic survey targeting 0.6 < z < 1.0, K-s -selected galaxies. The data release contains 3528 spectra with measured stellar velocity dispersions and stellar population properties, a 25-fold increase in sample size compared to previous work. This K ( s )-selected sample probes the galaxy population down to similar to 0.3L*, for all colors and morphological types. Along with the spectra, we publish a value-added catalog with stellar and ionized gas velocity dispersions, stellar absorption line indices, emission-line fluxes, and equivalent widths, complemented with structural parameters measured from Hubble Space Telescope Advanced Camera for Surveys imaging. With its combination of high precision and large sample size, LEGA-C provides a new benchmark for galaxy evolution studies.

The physical and chemical properties of the circumgalactic medium at z greater than or similar to 6 have been studied successfully through the absorption in the spectra of background quasi-stellar objects(1-3). One of the most crucial questions is to Investigate the nature and location of the source galaxies that give rise to these early metal absorbers(4-6). Theoretical models suggest that momentum-driven outflows from typical star-forming galaxies can eject metals into the circumgalactic medium and the intergalactic medium at z = 5-6 (refs. (7-9)). Deep, dedicated surveys have searched for Ly alpha emission associated with strong C IV absorbers at z approximate to 6, but only a few Ly alpha-emitter candidates have been detected. Interpreting these detections is moreover ambiguous because Ly alpha is a resonant line(10-12), raising the need for complementary techniques for detecting absorbers' host galaxies. Here we report a [C II] 158 mu m emitter detected using the Atacama Large Millimeter Array that is associated with a strong low-ionization absorber, O I, at z = 5.978. The projected impact parameter between O I and [C II] emitter is 20.0 kpc. The measured [CII] luminosity is 7.0 x 10(7) solar luminosities. Further analysis indicates that strong O I absorbers may reside in the circumgalactic medium of massive halos one to two orders of magnitude more massive than expected values(8,14).

Star formation rate (SFR) measurements at z>4 have relied mostly on the rest-frame far-ultraviolet (FUV) observations. The corrections for dust attenuation based on the IRX-beta relation are highly uncertain and are still debated in the literature. Hence, rest-frame far-infrared (FIR) observations are necessary to constrain the dust-obscured component of the SFR. In this paper, we exploit the rest-frame FIR continuum observations collected by the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) to directly constrain the obscured SFR in galaxies at 4.4

In this work, we study the evolution of the mass-metallicity relations (MZRs) as predicted by the GAlaxy Evolution and Assembly (gaea) semi-analytic model. We contrast these predictions with recent results from the VANDELS survey, which allows us to expand the accessible redshift range for the stellar MZR up to z similar to 3.5. We complement our study by considering the evolution of the gas-phase MZR in the same redshift range. We show that gaea is able to reproduce the observed evolution of the z < 3.5 gas-phase MZR and z < 0.7 stellar MZR, while it overpredicts the stellar metallicity at z similar to 3.5. Furthermore, gaea also reproduces the so-called fundamental metallicity relation (FMR) between gas-phase metallicity, stellar mass, and star formation rate (SFR). In particular, the gas-phase FMR in gaea is already in place at z similar to 5 and shows almost no evolution at lower redshift. gaea predicts the existence of a stellar FMR that is, however, characterized by a relevant redshift evolution, although its shape follows closely the gas-phase FMR. We also report additional unsolved tensions between model and data: the overall normalization of the predicted MZR agrees with observations only within similar to 0.1 dex; the largest discrepancies are seen at z similar to 3.5 where models tend to slightly overpredict observed metallicities; the slope of the predicted MZR at fixed SFR is too steep below a few M-circle dot yr(-1). Finally, we provide model predictions for the evolution of the MZRs at higher redshifts, which would be useful in the context of future surveys, like those that will be performed with James Webb Space Telescope.