Leo P. Singer, Mansi M. Kasliwal, S. Bradley Cenko, Daniel A. Perley, Gemma E. Anderson, G. C. Anupama, Iair Arcavi, Varun Bhalerao, Brian D. Bue, Yi Cao, Valerie Connaughton, Alessandra Corsi, Antonino Cucchiara, Rob P. Fender, Derek B. Fox, Neil Gehrels, Adam Goldstein, J. Gorosabel, Assaf Horesh, Kevin HurleyJoel Johansson, D. A. Kann, Chryssa Kouveliotou, Kuiyun Huang, S. R. Kulkarni, Frank Masci, Peter Nugent, Arne Rau, Umaa D. Rebbapragada, Tim D. Staley, Dmitry Svinkin, C. C. Thöne, A. De Ugarte Postigo, Yuji Urata, Alan Weinstein

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33 Scopus citations


The Fermi Gamma-ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi GRB Monitor instrument have posed a formidable obstacle to locating the bursts' host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target-of-opportunity mode for the intermediate Palomar Transient Factory in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: 8 afterglow discoveries out of 35 searches. Two of the bursts with detected afterglows (GRBs 130702A and 140606B) were at low redshift (z = 0.145 and 0.384, respectively) and had spectroscopically confirmed broad-line Type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samples. We identify one new outlier on the Amati relation. We find that two bursts are consistent with a mildly relativistic shock breaking out from the progenitor star rather than the ultra-relativistic internal shock mechanism that powers standard cosmological bursts. Finally, in the context of the Zwicky Transient Facility, we discuss how we will continue to expand this effort to find optical counterparts of binary neutron star mergers that may soon be detected by Advanced LIGO and Virgo.

Original languageEnglish
Article number52
JournalAstrophysical Journal
Issue number1
StatePublished - Jun 10 2015


  • gamma-ray burst: individual (GRB 130702A, GRB 140606B)
  • gravitational waves
  • methods: observational
  • supernovae: general
  • surveys

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    Singer, L. P., Kasliwal, M. M., Cenko, S. B., Perley, D. A., Anderson, G. E., Anupama, G. C., Arcavi, I., Bhalerao, V., Bue, B. D., Cao, Y., Connaughton, V., Corsi, A., Cucchiara, A., Fender, R. P., Fox, D. B., Gehrels, N., Goldstein, A., Gorosabel, J., Horesh, A., ... Weinstein, A. (2015). THE NEEDLE in the 100 deg2 HAYSTACK: UNCOVERING AFTERGLOWS of FERMI GRBs with the PALOMAR TRANSIENT FACTORY. Astrophysical Journal, 806(1), [52].