TY - JOUR
T1 - Identifying the host galaxy of the short GRB 100628A
AU - Nicuesa Guelbenzu, A.
AU - Klose, S.
AU - Palazzi, E.
AU - Greiner, J.
AU - Michalowski, M.~J.
AU - Kann, D.~A.
AU - Hunt, L.~K.
AU - Malesani, D.
AU - Rossi, A.
AU - Savaglio, S.
AU - Schulze, S.
AU - Xu, D.
AU - Afonso, P.~M.~J.
AU - Elliott, J.
AU - Ferrero, P.
AU - Filgas, R.
AU - Hartmann, D.~H.
AU - Krühler, T.
AU - Knust, F.
AU - Masetti, N.
AU - Olivares E., F.
AU - Rau, A.
AU - Schady, P.
AU - Schmidl, S.
AU - Tanga, M.
AU - Updike, A.~C.
AU - Varela, K.
PY - 2015/11
Y1 - 2015/11
N2 - We report on the results of a comprehensive observing campaign to reveal the host galaxy of the short GRB 100628A. This burst was followed by a faint X-ray afterglow but no optical counterpart was discovered. However, inside the X-ray error circle a potential host galaxy at a redshift of z = 0.102 was soon reported in the literature. If this system is the host, then GRB 100628A was the cosmologically most nearby unambiguous short burst with a measured redshift so far. We used the multi-colour imager GROND at the ESO/La Silla MPG 2.2 m telescope, ESO/VLT spectroscopy, and deep Australia Telescope Compact Array (ATCA) radio-continuum observations together with publicly available Gemini imaging data to study the putative host and the galaxies in the field of GRB 100628A. We confirm that inside the X-ray error circle the most probable host-galaxy candidate is the morphologically disturbed, interacting galaxy system at z = 0.102. The interacting galaxies are connected by a several kpc long tidal stream, which our VLT/FORS2 spectroscopy reveals strong emission lines of [O ii], [O iii], Hα and Hβ, characteristic for the class of extreme emission-line galaxies and indicative of ongoing star formation. The latter leaves open the possibility that the GRB progenitor was a member of a young stellar population. However, we indentify a second host-galaxy candidate slightly outside the X-ray error circle. It is a radio-bright, luminous elliptical galaxy at a redshift z = 0.311. With a K-band luminosity of 2 × 1011L⊙ this galaxy resembles the probable giant elliptical host of the first well-localized short burst, GRB 050509B. If this is the host, then the progenitor of GRB 100628A was a member of an old stellar population.
AB - We report on the results of a comprehensive observing campaign to reveal the host galaxy of the short GRB 100628A. This burst was followed by a faint X-ray afterglow but no optical counterpart was discovered. However, inside the X-ray error circle a potential host galaxy at a redshift of z = 0.102 was soon reported in the literature. If this system is the host, then GRB 100628A was the cosmologically most nearby unambiguous short burst with a measured redshift so far. We used the multi-colour imager GROND at the ESO/La Silla MPG 2.2 m telescope, ESO/VLT spectroscopy, and deep Australia Telescope Compact Array (ATCA) radio-continuum observations together with publicly available Gemini imaging data to study the putative host and the galaxies in the field of GRB 100628A. We confirm that inside the X-ray error circle the most probable host-galaxy candidate is the morphologically disturbed, interacting galaxy system at z = 0.102. The interacting galaxies are connected by a several kpc long tidal stream, which our VLT/FORS2 spectroscopy reveals strong emission lines of [O ii], [O iii], Hα and Hβ, characteristic for the class of extreme emission-line galaxies and indicative of ongoing star formation. The latter leaves open the possibility that the GRB progenitor was a member of a young stellar population. However, we indentify a second host-galaxy candidate slightly outside the X-ray error circle. It is a radio-bright, luminous elliptical galaxy at a redshift z = 0.311. With a K-band luminosity of 2 × 1011L⊙ this galaxy resembles the probable giant elliptical host of the first well-localized short burst, GRB 050509B. If this is the host, then the progenitor of GRB 100628A was a member of an old stellar population.
KW - gamma-ray burst
U2 - 10.1051/0004-6361/201425160
DO - 10.1051/0004-6361/201425160
M3 - Article
SN - 0004-6361
VL - 583
SP - 1
EP - 10
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A88
ER -