TY - JOUR
T1 - The host of GRB 030323 at z = 3.372
T2 - A very high column density DLA system with a low metallicity
AU - Vreeswijk, P. M.
AU - Ellison, S. L.
AU - Ledoux, C.
AU - Wijers, R. A.M.J.
AU - Fynbo, J. P.U.
AU - Møller, P.
AU - Henden, A.
AU - Hjorth, J.
AU - Masi, G.
AU - Rol, E.
AU - Jensen, B. L.
AU - Tanvir, N.
AU - Levan, A.
AU - Castro Cerón, J. M.
AU - Gorosabel, J.
AU - Castro-Tirado, A. J.
AU - Fruchter, A. S.
AU - Kouveliotou, C.
AU - Burud, I.
AU - Rhoads, J.
AU - Masetti, N.
AU - Palazzi, E.
AU - Pian, E.
AU - Pedersen, H.
AU - Kaper, L.
AU - Gilmore, A.
AU - Kilmartin, P.
AU - Buckle, J. V.
AU - Seigar, M. S.
AU - Hartmann, D. H.
AU - Lindsay, K.
AU - Van Den Heuvel, E. P.J.
PY - 2004/6
Y1 - 2004/6
N2 - We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Lyα (DLA) absorption and low- and high-ionization lines at a redshift z = 3.3718 ± 0.0005. The inferred neutral hydrogen column density, log N(H I) = 21.90 ± 0.07, is larger than any (GRB- or QSO-) DLA H I column density inferred directly from Lyα in absorption. From the afterglow photometry, we derive a conservative upper limit to the host-galaxy extinction: Av < 0.5 mag. The iron abundance is [Fe/H] = -1.47 ± 0.11, while the metallicity of the gas as measured from sulphur is [S/HJ = -1.26 ± 0.20. We derive an upper limit on the H2 molecular fraction of 2N(H2)/(2N(H2) + N(H I)) ≲ 10-6. In the Lyα trough, a Lyα emission line is detected, which corresponds to a star-formation rate (not corrected for dust extinction) of roughly 1 Modot; 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, 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 H I volume density to be nH I = 102-102 cm-3. HST/ACS imaging 4 months after the burst shows an extended AB(F606W) = 28.0 ± 0.3 mag object at a distance of 0″.14 (1 kpc) from the early afterglow location, which presumably is the host galaxy of GRB 030323.
AB - We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Lyα (DLA) absorption and low- and high-ionization lines at a redshift z = 3.3718 ± 0.0005. The inferred neutral hydrogen column density, log N(H I) = 21.90 ± 0.07, is larger than any (GRB- or QSO-) DLA H I column density inferred directly from Lyα in absorption. From the afterglow photometry, we derive a conservative upper limit to the host-galaxy extinction: Av < 0.5 mag. The iron abundance is [Fe/H] = -1.47 ± 0.11, while the metallicity of the gas as measured from sulphur is [S/HJ = -1.26 ± 0.20. We derive an upper limit on the H2 molecular fraction of 2N(H2)/(2N(H2) + N(H I)) ≲ 10-6. In the Lyα trough, a Lyα emission line is detected, which corresponds to a star-formation rate (not corrected for dust extinction) of roughly 1 Modot; 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, 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 H I volume density to be nH I = 102-102 cm-3. HST/ACS imaging 4 months after the burst shows an extended AB(F606W) = 28.0 ± 0.3 mag object at a distance of 0″.14 (1 kpc) from the early afterglow location, which presumably is the host galaxy of GRB 030323.
KW - Galaxies: distances and redshifts
KW - Galaxies: quasars: absorption lines
KW - Gamma rays: bursts
KW - ISM: dust, extinction
UR - http://www.scopus.com/inward/record.url?scp=19244372889&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=19244372889&partnerID=8YFLogxK
U2 - 10.1051/0004-6361:20040086
DO - 10.1051/0004-6361:20040086
M3 - Article
AN - SCOPUS:19244372889
SN - 0004-6361
VL - 419
SP - 927
EP - 940
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
IS - 3
ER -