Discovery of a Damped Ly Galaxy at z ∼ 3 toward the Quasar SDSS J011852+040644

• Published in: The Astrophysical journal 2021-02, Vol.908 (2)
• Main Authors: Joshi, Ravi, Fumagalli, Michele, Srianand, Raghunathan, Noterdaeme, Pasquier, Petitjean, Patrick, Rafelski, Marc, Mackenzie, Ruari, Li, Qiong, Cai, Zheng, Martin, D. Christopher, Zou, Siwei, Wu, Xue-Bing, Jiang, Linhua, Ho, Luis C.
• Format: Article
• Language: English
• Subjects: Damped Ly; Damped Lyman-alpha systems; Quasar absorption line spectroscopy; Star formation; systems
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/abd1d5

We report the detection of the host galaxy of a damped Ly system (DLA) with log N(H i) [cm−2] = 21.0 0.10 at z 3.0091 toward the background quasar SDSS J011852+040644 using the Palomar Cosmic Web Imager at the Hale (P200) telescope. We detect Ly emission in the dark core of the DLA trough at a 3.3 confidence level, with Ly luminosity of LLy = (3.8 0.8) × 1042 erg s−1, corresponding to a star formation rate of 2 M yr−1 (considering a lower limit on Ly escape fraction f esc Ly ∼ 2 % ) as typical for Lyman break galaxies at these redshifts. The Ly emission is blueshifted with respect to the systemic redshift derived from metal absorption lines by 281 43 km s−1. The associated galaxy is at very small impact parameter of 12 kpc from the background quasar, which is in line with the observed anticorrelation between column density and impact parameter in spectroscopic searches tracing the large-scale environments of DLA host galaxies.