Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/26459
 Title: The host of GRB 030323 at z = 3.372: A very high column density DLA system with a low metallicity Authors: Vreeswijk, P. M.Ellison, S. L.Ledoux, C.Ellison, S. L.Wijers, R. A. M. J.Rol, E.Kaper, L.Van Den Heuvel EPJFynbo, J. P. U.Fynbo, J. P. U.Hjorth, J.Jensen, B. L.Pedersen, H.Møller, P.Henden, A.Masi, G.Tanvir, N.Levan, A.Castro Cerón JMGorosabel, J.Fruchter, A. S.Burud, I.Rhoads, J.Gorosabel, J.Castro-Tirado, A. J.Kouveliotou, C.Masetti, N.Palazzi, E.Pian, E.Pian, E.Gilmore, A.Kilmartin, P.Buckle, J. V.Seigar, M. S.Hartmann, D. H.Lindsay, K. First Published: Jun-2004 Publisher: EDP Sciences for European Southern Observatory (ESO) Citation: Astronomy & Astrophysics, 2004, 419 (3), pp. 927-940 Abstract: We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Ly $\alpha$ (DLA) absorption and low- and high-ionization lines at a redshift $z=3.3718\pm0.0005$. The inferred neutral hydrogen column density, $\log N({\ion{H}{i}})=21.90\pm0.07$, is larger than any (GRB- or QSO-) DLA $\ion{H}{i}$ column density inferred directly from Ly $\alpha$ in absorption. From the afterglow photometry, we derive a conservative upper limit to the host-galaxy extinction: $A_{\rm V}<0.5$ mag. The iron abundance is $\rm [Fe/H]=-1.47\pm0.11$, while the metallicity of the gas as measured from sulphur is $\rm [S/H]=-1.26\pm0.20$. We derive an upper limit on the H 2 molecular fraction of $2N({\rm H_2)}/(2N{\rm (H_2)}+N({\ion{H}{i}}))\la10^{-6}$. In the Ly $\alpha$ trough, a Ly $\alpha$ emission line is detected, which corresponds to a star-formation rate (not corrected for dust extinction) of roughly 1 M $_{\odot}$ yr -1. All these results are consistent with the host galaxy of GRB 030323 consisting of a low metallicity gas with a low dust content. We detect fine-structure lines of silicon, $\ion{Si}{ii}$*, which have never been clearly detected in QSO-DLAs; this suggests that these lines are produced in the vicinity of the GRB explosion site. Under the assumption that these fine-structure levels are populated by particle collisions, we estimate the $\ion{H}{i}$ volume density to be $n_{\ion{H}{i}}=10^2{-}10^4$ cm -3. HST/ACS imaging 4 months after the burst shows an extended ${\it AB}(F606W)=28.0\pm0.3$ mag object at a distance of 014 (1 kpc) from the early afterglow location, which presumably is the host galaxy of GRB 030323. DOI Link: 10.1051/0004-6361:20040086 ISSN: 0004-6361 Links: http://hdl.handle.net/2381/26459http://www.aanda.org/articles/aa/abs/2004/21/aah4670/aah4670.html Version: Publisher Version Status: Peer-reviewed Type: Journal Article Rights: Copyright © 2004 ESO. Reproduced with permission from Astronomy & Astrophysics, © ESO. Appears in Collections: Published Articles, Dept. of Physics and Astronomy

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