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.
Description
[1307.5103] Evidence that Gamma-ray Burst 130702A Exploded in a Dwarf Satellite of a Massive Galaxy
%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
}