We introduce xCOLD GASS, a legacy survey providing a census of molecular gas in the local universe. Building on the original COLD GASS survey, we present here the full sample of 532 galaxies with CO ...(1-0) measurements from the IRAM 30 m telescope. The sample is mass-selected in the redshift interval from the Sloan Digital Sky Survey (SDSS) and therefore representative of the local galaxy population with . The CO (1-0) flux measurements are complemented by observations of the CO (2-1) line with both the IRAM 30 m and APEX telescopes, H i observations from Arecibo, and photometry from SDSS, WISE, and GALEX. Combining the IRAM and APEX data, we find that the ratio of CO (2-1) to CO (1-0) luminosity for integrated measurements is , with no systematic variations across the sample. The CO (1-0) luminosity function is constructed and best fit with a Schechter function with parameters , , and . With the sample now complete down to stellar masses of 109 , we are able to extend our study of gas scaling relations and confirm that both molecular gas fractions ( ) and depletion timescale ( ) vary with specific star formation rate (or offset from the star formation main sequence) much more strongly than they depend on stellar mass. Comparing the xCOLD GASS results with outputs from hydrodynamic and semianalytic models, we highlight the constraining power of cold gas scaling relations on models of galaxy formation.
We present the Super Eight galaxies-a set of very luminous, high-redshift (7.1 < z < 8.0) galaxy candidates found in the Brightest of Reionizing Galaxies (BoRG) Survey fields. The original sample ...includes eight galaxies that are Y-band dropout objects with H-band magnitudes of mH < 25.5. Four of these objects were originally reported in Calvi et al. Combining new Hubble Space Telescope (HST) WFC3/F814W imaging and Spitzer IRAC data with archival imaging from BoRG and other surveys, we explore the properties of these galaxies. Photometric redshift fitting places six of these galaxies in the redshift range of 7.1 < z < 8.0, resulting in three new high-redshift galaxies and confirming three of the four high-redshift galaxy candidates from Calvi et al. We calculate the half-light radii of the Super Eight galaxies using the HST F160W filter and find that the Super Eight sizes are in line with the typical evolution of size with redshift. The Super Eights have a mean mass of log (M*/M ) ∼10, which is typical for sources in this luminosity range. Finally, we place our sample on the UV z ∼ 8 luminosity function and find that the Super Eight number density is consistent with other surveys in this magnitude and redshift range.
We report on the detailed analysis of a gravitationally lensed Y-band dropout, A2744_YD4, selected from deep Hubble Space Telescope imaging in the Frontier Field cluster Abell 2744. Band 7 ...observations with the Atacama Large Millimeter/submillimeter Array (ALMA) indicate the proximate detection of a significant 1 mm continuum flux suggesting the presence of dust for a star-forming galaxy with a photometric redshift of . Deep X-SHOOTER spectra confirms the high-redshift identity of A2744_YD4 via the detection of Ly emission at a redshift z = 8.38. The association with the ALMA detection is confirmed by the presence of O iii 88 m emission at the same redshift. Although both emission features are only significant at the 4 level, we argue their joint detection and the positional coincidence with a high-redshift dropout in the Hubble Space Telescope images confirms the physical association. Analysis of the available photometric data and the modest gravitational magnification ( ) indicates A2744_YD4 has a stellar mass of ∼2 × 109 , a star formation rate of ∼20 yr−1 and a dust mass of ∼6 × 106 . We discuss the implications of the formation of such a dust mass only after the onset of cosmic reionization.
We present the Super Eight galaxies - a set of very luminous, high-redshift
($7.1<z<8.0$) galaxy candidates found in Brightest of Reionizing Galaxies
(BoRG) Survey fields. The original sample ...includes eight galaxies that are
$Y$-band dropout objects with $H$-band magnitudes of $m_H<25.5$. Four of these
objects were originally reported in Calvi et al. 2016. Combining new Hubble
Space Telescope (HST) WFC3/F814W imaging and $Spitzer$ IRAC data with archival
imaging from BoRG and other surveys, we explore the properties of these
galaxies. Photometric redshift fitting places six of these galaxies in the
redshift range of $7.1<z<8.0$, resulting in three new high-redshift galaxies
and confirming three of the four high-redshift galaxy candidates from Calvi et
al. 2016. We calculate the half-light radii of the Super Eight galaxies using
the HST F160W filter and find that the Super Eight sizes are in line with
typical evolution of size with redshift. The Super Eights have a mean mass of
log(M$_*$/M$_\odot$) $\sim10$, which is typical for sources in this luminosity
range. Finally, we place our sample on the UV $z\sim8$ luminosity function and
find that the Super Eight number density is consistent with other surveys in
this magnitude and redshift range.
We report on the detailed analysis of a gravitationally-lensed Y-band
dropout, A2744_YD4, selected from deep Hubble Space Telescope imaging in the
Frontier Field cluster Abell 2744. Band 7 ...observations with the Atacama Large
Millimeter Array (ALMA) indicate the proximate detection of a significant 1mm
continuum flux suggesting the presence of dust for a star-forming galaxy with a
photometric redshift of $z\simeq8$. Deep X-SHOOTER spectra confirms the high
redshift identity of A2744_YD4 via the detection of Lyman $\alpha$ emission at
a redshift $z$=8.38. The association with the ALMA detection is confirmed by
the presence of OIII 88$\mu$m emission at the same redshift. Although both
emission features are only significant at the 4 $\sigma$ level, we argue their
joint detection and the positional coincidence with a high redshift dropout in
the HST images confirms the physical association. Analysis of the available
photometric data and the modest gravitational magnification ($\mu\simeq2$)
indicates A2744_YD4 has a stellar mass of $\sim$ 2$\times$10$^9$ M$_{\odot}$, a
star formation rate of $\sim20$ M$_{\odot}$/yr and a dust mass of
$\sim$6$\times$10$^{6}$ M$_{\odot}$. We discuss the implications of the
formation of such a dust mass only $\simeq$200 Myr after the onset of cosmic
reionisation.
We introduce xCOLD GASS, a legacy survey providing a census of molecular gas in the local Universe. Building upon the original COLD GASS survey, we present here the full sample of 532 galaxies with ...CO(1-0) measurements from the IRAM-30m telescope. The sample is mass-selected in the redshift interval \(0.01<z<0.05\) from SDSS, and therefore representative of the local galaxy population with M\(_{\ast}>10^9\)M\(_{\odot}\). The CO(1-0) flux measurements are complemented by observations of the CO(2-1) line with both the IRAM-30m and APEX telescopes, HI observations from Arecibo, and photometry from SDSS, WISE and GALEX. Combining the IRAM and APEX data, we find that the CO(2-1) to CO(1-0) luminosity ratio for integrated measurements is \(r_{21}=0.79\pm0.03\), with no systematic variations across the sample. The CO(1-0) luminosity function is constructed and best fit with a Schechter function with parameters {\(L_{\mathrm{CO}}^* = (7.77\pm2.11) \times 10^9\,\mathrm{K\,km\,s^{-1}\, pc^{2}}\), \(\phi^{*} = (9.84\pm5.41) \times 10^{-4} \, \mathrm{Mpc^{-3}}\) and \(\alpha = -1.19\pm0.05\)}. With the sample now complete down to stellar masses of \(10^9\)M\(_{\odot}\), we are able to extend our study of gas scaling relations and confirm that both molecular gas fraction and depletion timescale vary with specific star formation rate (or offset from the star-formation main sequence) much more strongly than they depend on stellar mass. Comparing the xCOLD GASS results with outputs from hydrodynamic and semi-analytic models, we highlight the constraining power of cold gas scaling relations on models of galaxy formation.
We present the Super Eight galaxies - a set of very luminous, high-redshift (\(7.1<z<8.0\)) galaxy candidates found in Brightest of Reionizing Galaxies (BoRG) Survey fields. The original sample ...includes eight galaxies that are \(Y\)-band dropout objects with \(H\)-band magnitudes of \(m_H<25.5\). Four of these objects were originally reported in Calvi et al. 2016. Combining new Hubble Space Telescope (HST) WFC3/F814W imaging and \(Spitzer\) IRAC data with archival imaging from BoRG and other surveys, we explore the properties of these galaxies. Photometric redshift fitting places six of these galaxies in the redshift range of \(7.1<z<8.0\), resulting in three new high-redshift galaxies and confirming three of the four high-redshift galaxy candidates from Calvi et al. 2016. We calculate the half-light radii of the Super Eight galaxies using the HST F160W filter and find that the Super Eight sizes are in line with typical evolution of size with redshift. The Super Eights have a mean mass of log(M\(_*\)/M\(_\odot\)) \(\sim10\), which is typical for sources in this luminosity range. Finally, we place our sample on the UV \(z\sim8\) luminosity function and find that the Super Eight number density is consistent with other surveys in this magnitude and redshift range.
We report on the detailed analysis of a gravitationally-lensed Y-band dropout, A2744_YD4, selected from deep Hubble Space Telescope imaging in the Frontier Field cluster Abell 2744. Band 7 ...observations with the Atacama Large Millimeter Array (ALMA) indicate the proximate detection of a significant 1mm continuum flux suggesting the presence of dust for a star-forming galaxy with a photometric redshift of \(z\simeq8\). Deep X-SHOOTER spectra confirms the high redshift identity of A2744_YD4 via the detection of Lyman \(\alpha\) emission at a redshift \(z\)=8.38. The association with the ALMA detection is confirmed by the presence of OIII 88\(\mu\)m emission at the same redshift. Although both emission features are only significant at the 4 \(\sigma\) level, we argue their joint detection and the positional coincidence with a high redshift dropout in the HST images confirms the physical association. Analysis of the available photometric data and the modest gravitational magnification (\(\mu\simeq2\)) indicates A2744_YD4 has a stellar mass of \(\sim\) 2\(\times\)10\(^9\) M\(_{\odot}\), a star formation rate of \(\sim20\) M\(_{\odot}\)/yr and a dust mass of \(\sim\)6\(\times\)10\(^{6}\) M\(_{\odot}\). We discuss the implications of the formation of such a dust mass only \(\simeq\)200 Myr after the onset of cosmic reionisation.
With stunning clarity, JWST has revealed the Universe's first billion years. The scientific community is analyzing a wealth of JWST imaging and spectroscopic data from that era, and is in the process ...of rewriting the astronomy textbooks. Here, 1.5 years into the JWST science mission, we provide a snapshot of the great progress made towards understanding the initial chapters of our cosmic history. We highlight discoveries and breakthroughs, topics and issues that are not yet understood, and questions that will be addressed in the coming years, as JWST continues its revolutionary observations of the Early Universe. While this compendium is written by a small number of authors, invited to ISSI Bern in March 2024 as part of the 2024 ISSI Breakthrough Workshop, we acknowledge the work of a large community that is advancing our collective understanding of the evolution of the Early Universe.
PDF
