A quiescent galaxy at the position of the long GRB 050219A

Authors :: Rossi, A.
Piranomonte, S.
Savaglio, S.
Palazzi, E.
Michałowski, M. J.
Klose, S.
Hunt, L. K.
Amati, L.
Elliott, J.
Greiner, J.
Guidorzi, C.
Japelj, J.
Kann, D. A.
Faro, B. Lo
Guelbenzu, A. Nicuesa
Schulze, S.
Vergani, S. D.
Arnold, L. A.
Covino, S.
D'Elia, V.
Ferrero, P.
Filgas, R.
Goldoni, P.
Yoldaş, A. Küpcü
Borgne, D. Le
Pian, E.
Schady, P.
Stratta, G.
Source :: A&A 572, A47 (2014)
Publication Year :: 2014
Abstract: Long-duration gamma-ray bursts (LGRBs) are produced by the collapse of very massive stars. Due to the short lifetime of their progenitors, LGRBs pinpoint star-forming galaxies. We present here a multi-band search for the host galaxy of the long dark GRB 050219A within the enhanced Swift/XRT error circle. We used spectroscopic observations acquired with VLT/X-shooter to determine the redshift and star-formation rate of the putative host galaxy. We compared the results with the optical/IR spectral energy distribution obtained with different facilities. Surprisingly, the host galaxy is a old and quiescent early-type galaxy at z = 0.211 characterised by an unprecedentedly low specific star-formation rate. It is the first LGRB host to be also an early-type post-starburst galaxy. This is further evidence that GRBs can explode in all kind of galaxies, with the only requirement being an episode of star-formation.<br />Comment: 11 pages, 10 figures, 3 tables; accepted for publication in Astronomy & Astrophysics