We provide a coherent, uniform measurement of the evolution of the logarithmic star formation rate (SFR)-stellar mass (M*) relation, called the main sequence (MS) of star-forming galaxies , for ...star-forming and all galaxies out to . We measure the MS using mean stacks of 3 GHz radio-continuum images to derive average SFRs for ∼ 200,000 mass-selected galaxies at z > 0.3 in the COSMOS field. We describe the MS relation by adopting a new model that incorporates a linear relation at low stellar mass (log(M*/M ) < 10) and a flattening at high stellar mass that becomes more prominent at low redshift (z < 1.5). We find that the SFR density peaks at 1.5 < z < 2, and at each epoch there is a characteristic stellar mass (M* = 1-4 × 1010M ) that contributes the most to the overall SFR density. This characteristic mass increases with redshift, at least to z ∼ 2.5. We find no significant evidence for variations in the MS relation for galaxies in different environments traced by the galaxy number density at 0.3 < z < 3, nor for galaxies in X-ray groups at z ∼ 0.75. We confirm that massive bulge-dominated galaxies have lower SFRs than disk-dominated galaxies at a fixed stellar mass at z < 1.2. As a consequence, the increase in bulge-dominated galaxies in the local star-forming population leads to a flattening of the MS at high stellar masses. This indicates that "mass quenching" is linked with changes in the morphological composition of galaxies at a fixed stellar mass.
Aims.
We study the stellar (i.e., rest-optical) and dust-obscured star-forming (i.e., rest-mid-infrared) morphologies (i.e., sizes and Sérsic indices) of star-forming galaxies (SFGs) at 0.1 <
z
< ...2.5.
Methods.
We combined
Hubble
Space Telescope (HST) images from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) with JWST images from the Cosmic Evolution Early Release Science (CEERS) survey to measure the stellar and dust-obscured star formation distributions of 69 SFGs. Rest-mid-infrared (rest-MIR) morphologies were determined using a Markov chain Monte Carlo (MCMC) approach applied to the sharpest Mid-InfraRed Instrument (MIRI) images (i.e., shortest wavelength) dominated by dust emission (
S
ν
dust
/
S
ν
total
> 75%), as inferred for each galaxy from our optical-to-far-infrared spectral energy distribution fits with
CIGALE
. Rest-MIR Sérsic indices were only measured for the brightest MIRI sources, that is, with a signal-to-noise (S/N) greater than 75 (35 galaxies). At a lower S/N, simulations do indeed show that simultaneous measurements of both the size and Sérsic index become less reliable. We extended our study to fainter sources (i.e.,
S
/
N
> 10; 69 galaxies) by restricting our structural analysis to their rest-MIR sizes (
Re
MIR
) and by fixing their Sérsic index to a value of one.
Results.
Our MIRI-selected sample corresponds to a mass-complete sample (> 80%) of SFGs down to stellar masses 10
9.5
, 10
9.5
, and 10
10
M
⊙
at
z
∼ 0.3, 1, and 2, respectively. The rest-MIR Sérsic index of bright galaxies (
S
/
N
> 75) has a median value of 0.7
−0.3
+0.8
(the range corresponds to the 16th and 84th percentiles), which is in good agreement with their median rest-optical Sérsic indices. The Sérsic indices as well as the distribution of the axis ratio of these galaxies suggest that they have a disk-like morphology in the rest-MIR. Galaxies above the main sequence (MS) of star formation (i.e., starbursts) have rest-MIR sizes that are, on average, a factor ∼2 smaller than their rest-optical sizes (
Re
Opt.
). The median rest-optical to rest-MIR size ratio of MS galaxies increases with their stellar mass, from 1.1
−0.2
+0.4
at ∼10
9.8
M
⊙
to 1.6
−0.3
+1.0
at ∼10
11
M
⊙
. This mass-dependent trend resembles the one found in the literature between the rest-optical and rest-near-infrared sizes of SFGs, suggesting that it is primarily due to radial color gradients affecting rest-optical sizes and that the sizes of the stellar and star-forming components of SFGs are, on average, consistent at all masses. There is, however, a small population of SFGs (∼15%) with a compact star-forming component embedded in a larger stellar structure, with Re
Opt.
c
> 1.8 × Re
MIR
. This population could be the missing link between galaxies with an extended stellar component and those with a compact stellar component, the so-called blue nuggets.
Abstract
The PASSAGES (Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts) collaboration has recently defined a sample of 30 gravitationally lensed dusty star-forming galaxies ...(DSFGs). These rare, submillimeter-selected objects enable high-resolution views of the most extreme sites of star formation in galaxies at cosmic noon. Here, we present the first major compilation of strong lensing analyses using
lenstool
for PASSAGES, including 15 objects spanning
z
= 1.1–3.3, using complementary information from 0.″6-resolution 1.1 mm Atacama Large Millimeter/submillimeter Array and 0.″4 5 cm Jansky Very Large Array continuum imaging, in tandem with 1.6
μ
m Hubble and optical imaging with Gemini-S. Magnifications range from
μ
= 2 to 28 (median
μ
= 7), yielding intrinsic infrared luminosities of
L
IR
= 0.2–5.9 × 10
13
L
⊙
(median 1.4 × 10
13
L
⊙
) and inferred star formation rates of 170–6300
M
⊙
yr
−1
(median 1500
M
⊙
yr
−1
). These results suggest that the PASSAGES objects comprise some of the most extreme known starbursts, rivaling the luminosities of even the brightest unlensed objects, further amplified by lensing. The intrinsic sizes of far-infrared continuum regions are large (
R
e
= 1.7–4.3 kpc; median 3.0 kpc) but consistent with
L
IR
–
R
e
scaling relations for
z
> 1 DSFGs, suggesting a widespread spatial distribution of star formation. With modestly high angular resolution, we explore if these objects might be maximal starbursts. Instead of approaching Eddington-limited surface densities, above which radiation pressure will disrupt further star formation, they are safely sub-Eddington—at least on global, galaxy-integrated scales.
We report the results of a visual inspection of images of the Rapid ASKAP Continuum Survey (RACS) in search of extended radio galaxies (ERG) that reach or exceed linear sizes on the order of one ...Megaparsec. We searched a contiguous area of 1059 deg2 from RAJ = 20h20m to 06h20m, and −50∘<DecJ<−40∘, which is covered by deep multi-band optical images of the Dark Energy Survey (DES) and in which previously only three ERGs larger than 1 Mpc had been reported. For over 1800 radio galaxy candidates inspected, our search in optical and infrared images resulted in hosts for 1440 ERG, for which spectroscopic and photometric redshifts from various references were used to convert their largest angular size (LAS) to projected linear size (LLS). This resulted in 178 newly discovered giant radio sources (GRS) with LLS >1 Mpc, of which 18 exceed 2 Mpc and the largest one is 3.4 Mpc. Their redshifts range from 0.02 to ∼2.0, but only 10 of the 178 new GRS have spectroscopic redshifts. For the 146 host galaxies, the median r-band magnitude and redshift are 20.9 and 0.64, while for the 32 quasars or candidates these are 19.7 and 0.75. Merging the six most recent large compilations of GRS results in 458 GRS larger than 1 Mpc, so we were able to increase this number by ∼39% to 636.
A fascinating topic in radio astronomy is how to associate the complexity of observed radio structures with their environment in order to understand their interplay and the reason for the plethora of ...radio structures found in surveys. In this project, we explore the distortion of the radio structure of Fanaroff–Riley (FR)-type radio sources in the VLA-COSMOS Large Project at 3 GHz and relate it to their large-scale environment. We quantify the distortion by using the angle formed between the jets/lobes of two-sided FRs, namely bent angle (BA). Our sample includes 108 objects in the redshift range 0.08<z<3, which we cross-correlate to a wide range of large-scale environments (X-ray galaxy groups, density fields, and cosmic web probes) in the COSMOS field. The median BA of FRs in COSMOS at zmed∼0.9 is 167.5−37.5+11.5 degrees. We do not find significant correlations between BA and large-scale environments within COSMOS covering scales from a few kpc to several hundred Mpc, nor between BA and host properties. Finally, we compare our observational data to magnetohydrodynamical (MHD) adaptive-mesh simulations ENZO-MHD of two FR sources at z = 0.5 and at z = 1. Although the scatter in BA of the observed data is large, we see an agreement between observations and simulations in the bent angles of FRs, following a mild redshift evolution with BA. We conclude that, for a given object, the dominant mechanism affecting the radio structures of FRs could be the evolution of the ambient medium, where higher densities of the intergalactic medium at lower redshifts as probed by our study allow more space for jet interactions.
ABSTRACT
Hyperluminous infrared galaxies (HyLIRGs) are the most extreme star-forming systems observed in the early Universe, and their properties still elude comprehensive understanding. We have ...undertaken a large XMM–Newton observing programme to probe the total accreting black hole population in three HyLIRGs at z = 2.12, 3.25, and 3.55, gravitationally lensed by foreground galaxies. Selected from the Planck All-Sky Survey to Analyse Gravitationally lensed Extreme Starbursts (PASSAGES), these HyLIRGs have apparent infrared luminosities >1014 L⊙. Our observations revealed X-ray emission in each of them. PJ1336+49 appears to be dominated by high-mass X-ray binaries (HMXBs). Remarkably, the luminosity of this non-AGN X-ray emission exceeds by a factor of about 3 the value obtained by calibration with local galaxies with much lower star formation rates. This enhanced X-ray emission most likely highlights the efficacy of dynamical HMXB production within compact clusters, which is an important mode of star formation in HyLIRGs. The remaining two (PJ0116−24 and PJ1053+60) morphologically and spectrally exhibit a compact X-ray component in addition to the extended non-AGN X-ray emission, indicating the presence of Active Galactic Nuclei (AGNs). The AGN appears to be centrally located in the reconstructed source plane images of PJ0116−24, which manifests its star-forming activity predominantly within an extended galactic disc. In contrast, the AGN in the field of PJ1053+60 is projected 60 kpc away from the extreme star-forming galaxy and could be ejected from it. These results underline the synergistic potential of deep X-ray observations with strong lensing for the study of high-energy astrophysical phenomena in HyLIRGs.
ABSTRACT
We present a novel natural language processing (NLP) approach to deriving plain English descriptors for science cases otherwise restricted by obfuscating technical terminology. We address ...the limitations of common radio galaxy morphology classifications by applying this approach. We experimentally derive a set of semantic tags for the Radio Galaxy Zoo EMU (Evolutionary Map of the Universe) project and the wider astronomical community. We collect 8486 plain English annotations of radio galaxy morphology, from which we derive a taxonomy of tags. The tags are plain English. The result is an extensible framework, which is more flexible, more easily communicated, and more sensitive to rare feature combinations, which are indescribable using the current framework of radio astronomy classifications.
Context. In recent years, conflicting results have provided an uncertain view of the dust-attenuated star-forming properties of z ≳ 4 galaxies.Aims. To solve this, we need to accurately measure the ...mean dust-attenuated properties of star-forming galaxies (SFGs) at 4 < z < 5 and therefore constrain the cosmic dust-attenuated star formation rate density (SFRD) of the Universe 1.3 Giga-years after the Big Bang.Methods. We used the deepest optical-to-near-infrared data publicly available in the Cosmic Evolution Survey (COSMOS) field to build a mass-complete (> 109.5 M⊙) sample of SFGs at 4 < z < 5. Then, we measured their mean dust-attenuated properties (i.e., infrared luminosity, ⟨LIR⟩; dust-attenuated star formation rate, ⟨SFRIR⟩) by dividing our sample in three stellar mass (M*) bins (i.e., 109.5 < M*/M⊙ < 1010, 1010 < M*/M⊙ < 1010.5, and 1010.5 < M*/M⊙ < 1011.5) and by stacking in the uv domain all archival Atacama Large Millimeter/submillimeter Array (ALMA) band 6 and 7 observations available for these galaxies. Then, we combined this information with their mean rest-frame ultraviolet (UV) emission measured from the COSMOS2020 catalog (i.e., UV luminosity, ⟨LUV⟩; UV spectral slope, ⟨βUV⟩; and unattenuated SFR, ⟨SFRUV⟩), and constrained the IRX (≡LIR/LUV)–βUV, IRX–M*, and SFR–M* relations at z ∼ 4.5. Finally, using these relations and the stellar mass function of SFGs at z ∼ 4.5, we inferred the unattenuated and dust-attenuated SFRD at this epoch.Results. SFGs follow an IRX–βUV relation that is consistent with that observed in local starbursts. Our measurements favors a steepening of the IRX–M* relation at z ∼ 4.5, compared to the redshift-independent IRX–M* relation observed at z ∼ 1 − 3. Our galaxies lie on a linear SFR–M* relation, whose normalization varies by 0.3 dex, when we exclude or include from our stacks the ALMA primary targets (i.e., sources within 3″ from the ALMA phase center). The cosmic SFRD( > M*) converges at M* ≲ 109 M⊙, with SFGs at 108 < M*/M⊙ < 109 contributing already less than 15% of the SFRD from all SFGs with M* > 108 M⊙. The cosmic SFRD at z ∼ 4.5 is dominated by SFGs with a stellar mass of 109.5 − 10.5 M⊙. Finally, the fraction of the cosmic SFRD that is attenuated by dust, SFRDIR(> M*)/SFRD(> M*), is 90 ± 4% for M* = 1010 M⊙, 68 ± 10% for M* = 108.9 M⊙ (i.e., 0.03 × M⋆; M⋆ being the characteristic stellar mass of SFGs at this epoch) and this value converges to 60 ± 10% for M* = 108 M⊙.Conclusions. A non-evolving IRX–βUV relation suggests that the grain properties (e.g., size distribution, composition) of dust in SFGs at z ∼ 4.5 are similar to those in local starbursts. However, the mass and geometry of this dust result in lower attenuation in low-mass SFGs (≲1010 M⊙) at z ∼ 4.5 than at z ≲ 3. Nevertheless, the fraction of the cosmic SFRD that is attenuated by dust remains significant (∼68 ± 10%) even at such an early cosmic epoch.
Context. In recent years, conflicting results have provided an uncertain view of the dust-attenuated star-forming properties of z ≳ 4 galaxies. Aims. To solve this, we need to accurately measure the ...mean dust-attenuated properties of star-forming galaxies (SFGs) at 4 < z < 5 and therefore constrain the cosmic dust-attenuated star formation rate density (SFRD) of the Universe 1.3 Giga-years after the Big Bang. Methods. We used the deepest optical-to-near-infrared data publicly available in the Cosmic Evolution Survey (COSMOS) field to build a mass-complete (> 10 9.5 M ⊙ ) sample of SFGs at 4 < z < 5. Then, we measured their mean dust-attenuated properties (i.e., infrared luminosity, ⟨ L IR ⟩; dust-attenuated star formation rate, ⟨SFR IR ⟩) by dividing our sample in three stellar mass ( M * ) bins (i.e., 10 9.5 < M * / M ⊙ < 10 10 , 10 10 < M * / M ⊙ < 10 10.5 , and 10 10.5 < M * / M ⊙ < 10 11.5 ) and by stacking in the u v domain all archival Atacama Large Millimeter/submillimeter Array (ALMA) band 6 and 7 observations available for these galaxies. Then, we combined this information with their mean rest-frame ultraviolet (UV) emission measured from the COSMOS2020 catalog (i.e., UV luminosity, ⟨ L UV ⟩; UV spectral slope, ⟨ β UV ⟩; and unattenuated SFR, ⟨SFR UV ⟩), and constrained the IRX (≡ L IR / L UV )– β UV , IRX– M * , and SFR– M * relations at z ∼ 4.5. Finally, using these relations and the stellar mass function of SFGs at z ∼ 4.5, we inferred the unattenuated and dust-attenuated SFRD at this epoch. Results. SFGs follow an IRX– β UV relation that is consistent with that observed in local starbursts. Our measurements favors a steepening of the IRX– M * relation at z ∼ 4.5, compared to the redshift-independent IRX– M * relation observed at z ∼ 1 − 3. Our galaxies lie on a linear SFR– M * relation, whose normalization varies by 0.3 dex, when we exclude or include from our stacks the ALMA primary targets (i.e., sources within 3″ from the ALMA phase center). The cosmic SFRD( > M * ) converges at M * ≲ 10 9 M ⊙ , with SFGs at 10 8 < M * / M ⊙ < 10 9 contributing already less than 15% of the SFRD from all SFGs with M * > 10 8 M ⊙ . The cosmic SFRD at z ∼ 4.5 is dominated by SFGs with a stellar mass of 10 9.5 − 10.5 M ⊙ . Finally, the fraction of the cosmic SFRD that is attenuated by dust, SFRD IR (> M * )/SFRD(> M * ), is 90 ± 4% for M * = 10 10 M ⊙ , 68 ± 10% for M * = 10 8.9 M ⊙ (i.e., 0.03 × M ⋆ ; M ⋆ being the characteristic stellar mass of SFGs at this epoch) and this value converges to 60 ± 10% for M * = 10 8 M ⊙ . Conclusions. A non-evolving IRX– β UV relation suggests that the grain properties (e.g., size distribution, composition) of dust in SFGs at z ∼ 4.5 are similar to those in local starbursts. However, the mass and geometry of this dust result in lower attenuation in low-mass SFGs (≲10 10 M ⊙ ) at z ∼ 4.5 than at z ≲ 3. Nevertheless, the fraction of the cosmic SFRD that is attenuated by dust remains significant (∼68 ± 10%) even at such an early cosmic epoch.
Context. In recent years, conflicting results have provided an uncertain view of the dust-attenuated star-forming properties of z ≳ 4 galaxies.Aims. To solve this, we need to accurately measure the ...mean dust-attenuated properties of star-forming galaxies (SFGs) at 4 < z < 5 and therefore constrain the cosmic dust-attenuated star formation rate density (SFRD) of the Universe 1.3 Giga-years after the Big Bang.Methods. We used the deepest optical-to-near-infrared data publicly available in the Cosmic Evolution Survey (COSMOS) field to build a mass-complete (> 109.5 M⊙) sample of SFGs at 4 < z < 5. Then, we measured their mean dust-attenuated properties (i.e., infrared luminosity, ⟨LIR⟩; dust-attenuated star formation rate, ⟨SFRIR⟩) by dividing our sample in three stellar mass (M*) bins (i.e., 109.5 < M*/M⊙ < 1010, 1010 < M*/M⊙ < 1010.5, and 1010.5 < M*/M⊙ < 1011.5) and by stacking in the uv domain all archival Atacama Large Millimeter/submillimeter Array (ALMA) band 6 and 7 observations available for these galaxies. Then, we combined this information with their mean rest-frame ultraviolet (UV) emission measured from the COSMOS2020 catalog (i.e., UV luminosity, ⟨LUV⟩; UV spectral slope, ⟨βUV⟩; and unattenuated SFR, ⟨SFRUV⟩), and constrained the IRX (≡LIR/LUV)–βUV, IRX–M*, and SFR–M* relations at z ∼ 4.5. Finally, using these relations and the stellar mass function of SFGs at z ∼ 4.5, we inferred the unattenuated and dust-attenuated SFRD at this epoch.Results. SFGs follow an IRX–βUV relation that is consistent with that observed in local starbursts. Our measurements favors a steepening of the IRX–M* relation at z ∼ 4.5, compared to the redshift-independent IRX–M* relation observed at z ∼ 1 − 3. Our galaxies lie on a linear SFR–M* relation, whose normalization varies by 0.3 dex, when we exclude or include from our stacks the ALMA primary targets (i.e., sources within 3″ from the ALMA phase center). The cosmic SFRD( > M*) converges at M* ≲ 109 M⊙, with SFGs at 108 < M*/M⊙ < 109 contributing already less than 15% of the SFRD from all SFGs with M* > 108 M⊙. The cosmic SFRD at z ∼ 4.5 is dominated by SFGs with a stellar mass of 109.5 − 10.5 M⊙. Finally, the fraction of the cosmic SFRD that is attenuated by dust, SFRDIR(> M*)/SFRD(> M*), is 90 ± 4% for M* = 1010 M⊙, 68 ± 10% for M* = 108.9 M⊙ (i.e., 0.03 × M⋆; M⋆ being the characteristic stellar mass of SFGs at this epoch) and this value converges to 60 ± 10% for M* = 108 M⊙.Conclusions. A non-evolving IRX–βUV relation suggests that the grain properties (e.g., size distribution, composition) of dust in SFGs at z ∼ 4.5 are similar to those in local starbursts. However, the mass and geometry of this dust result in lower attenuation in low-mass SFGs (≲1010 M⊙) at z ∼ 4.5 than at z ≲ 3. Nevertheless, the fraction of the cosmic SFRD that is attenuated by dust remains significant (∼68 ± 10%) even at such an early cosmic epoch.
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