Discovery of a damped Ly$\alpha$ galaxy at z $\sim$ 3 towards the quasar SDSS J011852+040644

Abstract

We report the detection of the host galaxy of a damped Ly$\alpha$ system (DLA) with log N(HI) $[\mathrm{c}{\mathrm{m}}^{-2}]$ = $21.0\pm 0.10$ at $z\approx 3.0091$ towards the background quasar SDSS J011852+040644 using the Palomar Cosmic Web Imager (PCWI) at the Hale (P200) telescope. We detect Ly$\alpha$ emission in the dark core of the DLA trough at a 3.3$\sigma$ confidence level, with Ly$\alpha$ luminosity of $L_{\mathrm{Ly}\alpha }$ $=(3.8\pm 0.8)\times 10^{42}\mathrm{erg}{\mathrm{s}}^{-1}$, corresponding to a star formation rate of $\gtrsim 2{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$ (considering a lower limit on Ly$\alpha$ escape fraction $f_{esc}^{Ly\alpha }\sim 2\%$) as typical for Lyman break galaxies at these redshifts. The Ly$\alpha$ emission is blueshifted with respect to the systemic redshift derived from metal absorption lines by $281\pm 43$ km/s. The associated galaxy is at very small impact parameter of $\lesssim 12\mathrm{kpc}$ 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.

9 Pages, 5 Figures, Accepted for the Publication in ApJ

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Cited by in corpus (3)

• MUSE-ALMA Haloes VII: Survey Science Goals & Design, Data Processing and Final Catalogues
• Damped Ly-alpha Absorbers in Star-forming Galaxies at z < 0.15 Detected with the Hubble Space Telescope and Implications for Galaxy Evolution
• A survey of Ly$\alpha$ emission around Damped Ly$\alpha$ absorbers at $z\approx 2$ with the Keck Cosmic Web Imager