A Carbon-enhanced Lyman Limit System: Signature of the First Generation of Stars?

Abstract

We present the study of a Lyman limit system (LLS) at $z_{\mathrm{abs}}$ = 1.5441 towards quasar J134122.50+185213.9 observed with VLT X-shooter. This is a very peculiar system with strong C I absorption seen associated with a neutral hydrogen column density of log $N$(H I) (cm${}^{-2}$) = 18.10, too small to shield the gas from any external UV flux. The low ionization absorption lines exhibit a simple kinematic structure consistent with a single component. Using CLOUDY models to correct for ionization, we find that the ionization parameter of the gas is in the range $-$ 4.5 $<$ log $U$ $<$ $-$4.2 and the gas density $-$1.5 $<$ log $n$(H) (cm${}^{-3}$) $<$ $-$1.2. The models suggest that carbon is overabundant relative to iron, [C/Fe] $>$ +2.2 at [Fe/H] $\sim$ $-$1.6. Such a metal abundance pattern is reminiscent of carbon-enhanced metal-poor stars detected in the Galaxy halo. Metal enrichment by the first generation of supernovae provides a plausible explanation for the inferred abundance pattern in this system.

arXiv comment10 pages, 5 figures. Accepted for publication in ApJ

References in corpus (52)

• The chemical composition of the Sun
• The Seventh Data Release of the Sloan Digital Sky Survey
• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• The Circumgalactic Medium
• The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
• Damped Lyman alpha Systems
• Updated stellar yields from Asymptotic Giant Branch models
• Nucleosynthesis and Evolution of Massive Metal-Free Stars
• Near-Field Cosmology with Metal-Poor Stars
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• Structure and Kinematics of the Stellar Halos and Thick Disks of the Milky Way Based on Calibration Stars from SDSS DR7
• The Stellar Abundances for Galactic Archeology (SAGA) Database - Compilation of the Characteristics of Known Extremely Metal-Poor Stars
• First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star
• The Evolution of Isotope Ratios in the Milky Way Galaxy
• The early star generations: the dominant effect of rotation on the CNO yields
• The Binary Frequency Among Carbon-Enhanced, s-Process Rich, Metal-Poor Stars
• Supernova Nucleosynthesis in Population III 13 -- 50 $M_{\odot }$ Stars and Abundance Patterns of Extremely Metal-Poor Stars
• The first chemical enrichment in the universe and the formation of hyper metal-poor stars
• The s-Process in Low Metallicity Stars. II. Interpretation of High-Resolution Spectroscopic Observations with AGB models
• HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich
• Is HE0107-5240 A Primordial Star? -- The Characteristics of Extremely Metal-Poor Carbon-Rich Stars --
• Binarity in Carbon-Enhanced Metal-Poor stars
• Detection of Pristine Gas Two Billion Years after the Big Bang
• New synthesis models of consistent extragalactic background light over cosmic time
• Abundance Profiling of Extremely Metal-Poor Stars and Supernova Properties in the Early Universe
• An X-shooter composite of bright 1 < z < 2 quasars from UV to infrared
• Stellar Archaeology -- Exploring the Universe with Metal-Poor Stars
• Carbon-Enhanced Metal-Poor Stars in the Inner and Outer Halo Components of the Milky Way
• s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models
• The Stellar Metallicity Distribution Function of the Galactic Halo from SDSS Photometry
• The chemical compositions of the extreme halo stars HE0107-5240 and HE1327-2326 inferred from 3D hydrodynamical model atmospheres
• The physical properties of z>2 Lyman limit systems: new constraints for feedback and accretion models
• Elemental abundances and classification of CEMP stars
• Carbon-Enhanced Metal-Poor Stars: Relics from the Dark Ages
• Physical conditions in QSO absorbers from fine-structure absorption lines
• The first stars: CEMP--no stars and signatures of spinstars
• Faint Population III supernovae as the origin of the most iron-poor stars
• A Carbon-enhanced Metal-poor Damped Lyman alpha System: Probing Gas from Population III Nucleosynthesis?
• The lowest detected stellar Fe abundance: The halo star SMSS J160540.18-144323.1
• Metal-Poor Stars Observed with the Magellan Telescope I. Constraints on Progenitor Mass and Metallicity of AGB Stars Undergoing s-Process Nucleosynthesis
• Chemical Enrichment in the Carbon-enhanced Damped Lyman $\alpha$ System
• How plausible are the proposed formation scenarios of CEMP-r/s stars?
• The Keck+Magellan Survey for Lyman Limit Absorption III: Sample Definition and Column Density Measurements
• Spotting high-z molecular absorbers using neutral carbon: Results from a complete spectroscopic survey with the VLT
• A new candidate for probing Population III nucleosynthesis with carbon-enhanced damped Lyman-alpha systems
• The Most Metal-Poor Stars. V. The CEMP-no Stars in 3D and Non-LTE
• A study of low-metallicity DLAs at high redshift and C II* as a probe of their physical conditions
• Formation of carbon-enhanced metal-poor stars as a consequence of inhomogeneous metal mixing
• Measurement of Noisy Absorption Lines using the Apparent Optical Depth Technique
• Near Infrared spectroscopic observations of high redshift C~{\sc i} absorbers
• Exploring the origins of a new, apparently metal-free gas cloud at z = 4.4

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• Machine learning detects multiplicity of the first stars in stellar archaeology data
• Evidence of First Stars-enriched Gas in High-redshift Absorbers
• Towards ultra metal-poor DLAs: linking the chemistry of the most metal-poor DLA to the first stars
• Metal-Poor Stars Observed with the Southern African Large Telescope II. An Extended Sample
• A survey of extremely metal-poor gas at cosmic noon: evidence of elevated [O/Fe]