Connecting GRBs and ULIRGs: A Sensitive, Unbiased Survey for Radio Emission from Gamma-Ray Burst Host Galaxies at 0 < z < 2.5
Luminous infrared galaxies and submillimeter galaxies contribute significantly to stellar mass assembly and provide an important test of the connection between the gamma-ray burst (GRB) rate and that of overall cosmic star formation. We present sensitive 3 GHz radio observations using the Karl G. Jansky Very Large Array of 32 uniformly selected GRB host galaxies spanning a redshift range from 0 < z < 2.5, providing the first fully dust- and sample-unbiased measurement of the fraction of GRBs originating from the universe's most bolometrically luminous galaxies. Four galaxies are detected, with inferred radio star formation rates (SFRs) ranging between 50 and 300 M_☉ yr^(–1). Three of the four detections correspond to events consistent with being optically obscured "dark" bursts. Our overall detection fraction implies that between 9% and 23% of GRBs between 0.5 < z < 2.5 occur in galaxies with S_(3GHz) > 10 μJy, corresponding to SFR > 50 M_☉ yr^(–1) at z ~ 1 or >250 M_☉ yr^(–1) at z ~ 2. Similar galaxies contribute approximately 10%-30% of all cosmic star formation, so our results are consistent with a GRB rate that is not strongly biased with respect to the total SFR of a galaxy. However, all four radio-detected hosts have stellar masses significantly lower than IR/submillimeter-selected field galaxies of similar luminosities. We suggest that the GRB rate may be suppressed in metal-rich environments but independently enhanced in intense starbursts, producing a strong efficiency dependence on mass but little net dependence on bulk galaxy SFR.
© 2015 American Astronomical Society. Received 2014 July 16; accepted 2015 January 12; published 2015 March 11. Support for this work was provided by NASA through Hubble Fellowship grant HST-HF-51296.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA; the Observatory was made possible by the generous financial support of the W. M. Keck Foundation. We extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Partial support for this work was provided by NASA through an award issued by JPL/Caltech. It is also based in part on observations with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. These observations are associated with program GO-12949. We thank F. Owen for discussions regarding deep radio field surveys, C. Casey for advice regarding the star formation rates and masses of submillimeter- and Herschel-selected galaxy populations, and D. A. Kann for helpful comments. We thank U. Rau for assistance with analysis of the GRB 061110A data set, and H. Knutson, M. Zhao, and J. Curtis for acquiring the J and Ks imaging of GRB 051006.We also thank the anonymous referee for helpful suggestions that improved the quality of the paper. This manuscript was completed during the "Fast and Furious: Understanding Exotic Astrophysical Transients" workshop at the Aspen Center for Physics, which is supported in part by the NSF under grant No. PHYS-1066293. Facilities: VLA, Keck:I (LRIS), Hale (WIRC), Spitzer, HST (WFC3).
Published - 0004-637X_801_2_102.pdf
Submitted - 1407.4456v3.pdf