%0 Generic %1 kelly2013evidence %A Kelly, Patrick L. %A Filippenko, Alexei V. %A Fox, Ori D. %A Zheng, Weikang %A Clubb, Kelsey I. %D 2013 %K galaxy grb metallicity %T Evidence that Gamma-ray Burst 130702A Exploded in a Dwarf Satellite of a Massive Galaxy %U http://arxiv.org/abs/1307.5103 %X GRB 130702A is a nearby long-duration gamma-ray burst (LGRB) discovered by the Fermi satellite whose associated afterglow was detected by the Palomar Transient Factory. Subsequent photometric and spectroscopic monitoring has identified a coincident broad-lined Type Ic supernova (SN), and nebular emission detected near the explosion site is consistent with a redshift of z=0.145. The SN-GRB exploded at an offset of ~7.6" from the center of an inclined r=18.1 mag red disk-dominated galaxy, and ~0.6" from the center of a much fainter r=23 mag object. We obtained Keck-II DEIMOS spectra of the two objects and find a 2\sigma upper limit on their line-of-sight velocity offset of ~<60 km/s. If we project the SN-GRB coordinates onto the plane of the inclined massive disk galaxy, the explosion would have a ~61+-10 kpc offset, or ~6 times the galaxy's half-light radius. This large estimated nuclear offset suggests that the faint source is not a star-forming region of the massive red galaxy but is instead a dwarf galaxy. The star-formation rate of the dwarf galaxy is ~0.05 solar masses per year, and we place an upper limit on its oxygen abundance of 12 + log(O/H) < 8.16 dex. The identification of an LGRB in a dwarf satellite of a massive, metal-rich primary galaxy suggests that recent detections of LGRBs spatially coincident with metal-rich galaxies may be, in some cases, superpositions.

@misc{kelly2013evidence, abstract = {GRB 130702A is a nearby long-duration gamma-ray burst (LGRB) discovered by the Fermi satellite whose associated afterglow was detected by the Palomar Transient Factory. Subsequent photometric and spectroscopic monitoring has identified a coincident broad-lined Type Ic supernova (SN), and nebular emission detected near the explosion site is consistent with a redshift of z=0.145. The SN-GRB exploded at an offset of ~7.6" from the center of an inclined r=18.1 mag red disk-dominated galaxy, and ~0.6" from the center of a much fainter r=23 mag object. We obtained Keck-II DEIMOS spectra of the two objects and find a 2{\sigma} upper limit on their line-of-sight velocity offset of ~<60 km/s. If we project the SN-GRB coordinates onto the plane of the inclined massive disk galaxy, the explosion would have a ~61+-10 kpc offset, or ~6 times the galaxy's half-light radius. This large estimated nuclear offset suggests that the faint source is not a star-forming region of the massive red galaxy but is instead a dwarf galaxy. The star-formation rate of the dwarf galaxy is ~0.05 solar masses per year, and we place an upper limit on its oxygen abundance of 12 + log(O/H) < 8.16 dex. The identification of an LGRB in a dwarf satellite of a massive, metal-rich primary galaxy suggests that recent detections of LGRBs spatially coincident with metal-rich galaxies may be, in some cases, superpositions.}, added-at = {2013-07-22T18:58:38.000+0200}, author = {Kelly, Patrick L. and Filippenko, Alexei V. and Fox, Ori D. and Zheng, Weikang and Clubb, Kelsey I.}, biburl = {https://www.bibsonomy.org/bibtex/202341899cd73d354067a48290cf3208f/miki}, description = {[1307.5103] Evidence that Gamma-ray Burst 130702A Exploded in a Dwarf Satellite of a Massive Galaxy}, interhash = {ee38fb1d0d3807df05b7ba6c063a8870}, intrahash = {02341899cd73d354067a48290cf3208f}, keywords = {galaxy grb metallicity}, note = {cite arxiv:1307.5103Comment: Submitted to ApJ Letters, comments welcome}, timestamp = {2013-07-22T18:58:38.000+0200}, title = {Evidence that Gamma-ray Burst 130702A Exploded in a Dwarf Satellite of a Massive Galaxy}, url = {http://arxiv.org/abs/1307.5103}, year = 2013 }