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iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-energy Trigger

Cenko, S. Bradley and Perley, Daniel A. and Cao, Yi and Kulkarni, S. R. and Laher, Russ and Kasliwal, M. M. (2015) iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-energy Trigger. Astrophysical Journal Letters, 803 (2). Art. No. L24. ISSN 2041-8205.

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We report here the discovery by the Intermediate Palomar Transient Factory (iPTF) of iPTF14yb, a luminous (M_r ≈ 27.8 mag), cosmological (redshift 1.9733), rapidly fading optical transient. We demonstrate, based on probabilistic arguments and a comparison with the broader population, that iPTF14yb is the optical afterglow of the long-duration gamma-ray burst GRB 140226A. This marks the first unambiguous discovery of a GRB afterglow prior to (and thus entirely independent of) an associated high-energy trigger. We estimate the rate of iPTF14yb-like sources (i.e., cosmologically distant relativistic explosions) based on iPTF observations, inferring an all-sky value of yr^−1 (68% confidence interval of 110–2000 yr−1). Our derived rate is consistent (within the large uncertainty) with the all-sky rate of on-axis GRBs derived by the Swift satellite. Finally, we briefly discuss the implications of the nondetection to date of bona fide "orphan" afterglows (i.e., those lacking detectable high-energy emission) on GRB beaming and the degree of baryon loading in these relativistic jets.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Cenko, S. Bradley0000-0003-1673-970X
Perley, Daniel A.0000-0001-8472-1996
Cao, Yi0000-0002-8036-8491
Kulkarni, S. R.0000-0001-5390-8563
Laher, Russ0000-0003-2451-5482
Kasliwal, M. M.0000-0002-5619-4938
Alternate Title:iPTF14yb: The First Discovery of a GRB Afterglow Independent of a High-Energy Trigger
Additional Information:© 2015 The American Astronomical Society. Received 2015 February 20; accepted 2015 March 26; published 2015 April 20. We thank David Jewitt for executing our Keck/LRIS ToO observations, and Eran Ofek, Leo Singer, and Eric Bellm for comments on this manuscript. A.L.U. was supported by NSF grants PHY-0970074 and PHY-1307429 at the UWM Research Growth Initiative. J.F.G. acknowledges the Sofja Kovalevskaja award to P. Schady from the Alexander von Humboldt Foundation Germany. D.A.K. thanks TLS Tautenburg for financial support. The work of A.V.F. was made possible by NSF grant AST-1211916, the TABASGO Foundation, Gary and Cynthia Bengier, and the Christopher R. Redlich Fund. J.X.P. received funding from NASA grants NNX13AP036 and NNX14AI95G. This paper is based in part on observations obtained with the P48 Oschin telescope as part of the Intermediate Palomar Transient Factory project, a scientific collaboration among the Caltech, LANL, UW-Milwaukee, the Oskar Klein Center, the Weizmann Institute of Science, the TANGO Program of the University System of Taiwan, and the Kavli IPMU. LANL participation in iPTF is supported by the US Department of Energy as part of the Laboratory of Directed Research and Development program. The National Energy Research Scientific Computing Center provided staff, computational resources, and data storage for this project. Part of the funding for GROND (both hardware and personnel) was generously granted from the Leibniz-Prize to Prof. G. Hasinger (DFG grant HA 1850/28-1). Some of the data presented herein were obtained at the W.M. Keck Observatory, which 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 thank the RATIR project team and the staff of the Observatorio Astronómico Nacional on Sierra San Pedro Màrtir. RATIR is a collaboration between the University of California, the Universidad Nacional Autonóma de México, NASA Goddard Space Flight Center, and Arizona State University, benefiting from the loan of an H2RG detector and hardware and software support from Teledyne Scientific and Imaging. RATIR, the automation of the Harold L. Johnson Telescope of the Observatorio Astronómico Nacional on Sierra San Pedro Mártir, and the operation of both are funded through NASA grants NNX09AH71G, NNX09AT02G, NNX10AI27G, and NNX12AE66G, CONACyT grants INFR-2009-01-122785 and CB-2008-101958, UNAM PAPIIT grant IN113810, and UC MEXUS-CONACyT grant CN 09-283. Facilities: PO:1.2m (PTF), Keck:I (LRIS), Magellan: Baade (IMACS), Lulin (TRIPOL), Max Planck:2.2m (GROND), OANSPM:HJT (RATIR), VLA, CARMA, Swift (XRT)
Group:Palomar Transient Factory
Funding AgencyGrant Number
Alexander von Humboldt FoundationUNSPECIFIED
Gary and Cynthia BengierUNSPECIFIED
Christopher R. Redlich FundUNSPECIFIED
Subject Keywords:gamma-ray burst: general; stars: flare; supernovae: general
Issue or Number:2
Record Number:CaltechAUTHORS:20150522-095957473
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Official Citation:iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-energy Trigger S. Bradley Cenko et al. 2015 ApJ 803 L24
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57771
Deposited By: Jason Perez
Deposited On:27 May 2015 14:47
Last Modified:03 Mar 2020 13:01

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