The Cosmic Ultraviolet Baryon Survey (CUBS) II: Discovery of an H${}_2$-Bearing DLA in the Vicinity of an Early-Type Galaxy at z = 0.576

Abstract

We report the serendipitous detection of an H${}_2$-bearing damped Lyman-$\alpha$ absorber at z = 0.576 in the spectrum of the QSO J0111-0316 in the Cosmic Ultraviolet Baryon Survey. Spectroscopic observations from HST-COS in the far-ultraviolet reveal a damped absorber with log[N(HI)/cm^-2] = 20.1 +/- 0.2 and log[N(H${}_2$)/cm^-2] = 18.97 (-0.06, +0.05). The diffuse molecular gas is found in two velocity components separated by dv = 60 km/s, with >99.9% of the total H${}_2$ column density concentrated in one component. At a metallicity of $\approx$ 50% of solar, there is evidence for Fe enhancement and dust depletion, with a dust-to-gas ratio ${\kappa }_{\text{O}}\approx$ 0.4. A galaxy redshift survey conducted with IMACS and LDSS-3C on Magellan reveals an overdensity of nine galaxies at projected distance d <= 600 proper kpc (pkpc) and line-of-sight velocity offset dv${}_g$ <= 300 km/s from the absorber. The closest is a massive, early-type galaxy at d = 41 pkpc which contains $\approx$ 70% of the total stellar mass identified at d <= 310 pkpc of the H${}_2$ absorber. The close proximity of the H${}_2$-bearing gas to the quiescent galaxy and the Fe-enhanced chemical abundance pattern of the absorber suggest a physical connection, in contrast to a picture in which DLAs are primarily associated with gas-rich dwarfs. This case study illustrates that deep galaxy redshift surveys are needed to gain insight into the diverse environments that host dense and potentially star-forming gas.

19 pages, 6 figures. Accepted for publication in ApJ

References in corpus (27)

• H3+ in Diffuse Interstellar Clouds: a Tracer for the Cosmic-Ray Ionization Rate
• Velocity-Metallicity Correlation for high-z DLA Galaxies: Evidence for a Mass-Metallicity Relation?
• Molecular hydrogen in high-redshift Damped Lyman-alpha systems: The VLT/UVES database
• Powerful High Velocity-Dispersion Molecular Hydrogen Associated with an Intergalactic Shock Wave in Stephan's Quintet
• On the possible environmental effect in distributing heavy elements beyond individual gaseous halos
• The origin of fast molecular outflows in quasars: molecule formation in AGN-driven galactic winds
• Dense Molecular Gas Tracers in the Outflow of the Starburst Galaxy NGC 253
• A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy
• Molecular Gas in the Halo Fuels the Growth of a Massive Cluster Galaxy at High Redshift
• Dust-depletion sequences in damped Lyman-α absorbers: a unified picture from low-metallicity systems to the Galaxy
• Metallicity as a criterion to select H2 bearing Damped Lyman-alpha systems
• Excitation mechanisms in newly discovered H2-bearing Damped Lyman-alpha clouds: systems with low molecular fractions
• The Clustering of MgII Absorption Systems at z=0.5 and Detection of Cold Gas in Massive Halos
• The Cosmic Ultraviolet Baryon Survey (CUBS) I. Overview and the diverse environments of Lyman limit systems at z<1
• Powerful H2 Line Cooling in Stephan's Quintet II. Group-wide Gas and Shock Modeling of the Warm H2 and a Comparison with [CII]157.7um Emission and Kinematics
• Molecular hydrogen absorption systems in Sloan Digital Sky Survey
• X-shooter observations of strong H${}_2$-bearing DLAs at high redshift
• An HST/COS survey of molecular hydrogen in DLAs & sub-DLAs at z < 1: Molecular fraction and excitation temperature
• Isolated OB Associations in Stripped HI Gas Clouds
• Extended Star Formation and Molecular Gas in the Tidal Arms near NGC3077
• Directional Radiation and Photodissociation Regions in Molecular Hydrogen Clouds
• Proximate Molecular Quasar Absorbers: Excess of damped H2 systems at zabs~zQSO in SDSS DR14
• The cold circumgalactic environment of MAMMOTH-I: dynamically cold gas in the core of an Enormous Ly-alpha Nebula
• On the radial profile of gas-phase Fe/α ratio around distant galaxies
• Cold parsec-scale gas in a zabs~0.1 sub-DLA with disparate H2 and 21-cm absorption
• Evidence for Late-Time Feedback from the Discovery of Multiphase Gas in a Massive Elliptical at $z=0.4$
• Molecular hydrogen from z = 0.0963 DLA towards the QSO J1619+3342

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