Radio Follow-up of Gravitational-wave Triggers during Advanced LIGO O1
We present radio follow-up observations carried out with the Karl G. Jansky Very Large Array during the first observing run (O1) of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). A total of three gravitational-wave triggers were followed-up during the ≈ 4 months of O1, from 2015 September to 2016 January. Two of these triggers, GW150914 and GW151226, are binary black hole (BH) merger events of high significance. A third trigger, G194575, was subsequently declared as an event of no interest (i.e., a false alarm). Our observations targeted selected optical transients identified by the intermediate Palomar Transient Factory in the Advanced LIGO error regions of the three triggers, and a limited region of the gravitational-wave localization area of G194575 not accessible to optical telescopes due to Sun constraints, where a possible high-energy transient was identified. No plausible radio counterparts to GW150914 and GW151226 were found, in agreement with expectations for binary BH mergers. We show that combining optical and radio observations is key to identifying contaminating radio sources that may be found in the follow-up of gravitational-wave triggers, such as emission associated with star formation and active galactic nuclei. We discuss our results in the context of the theoretical predictions for radio counterparts to gravitational-wave transients, and describe our future plans for the radio follow-up of Advanced LIGO (and Virgo) triggers.
© 2016 The American Astronomical Society. Received 2016 August 22; Accepted 2016 September 14; Published 2016 September 28. A.C. thanks K. Hotokezaka and S. Nissanke for graciously providing the theoretical radio light curves of NS–NS mergers. A.C. acknowledges support from the NSF CAREER award #1455090. A.C. and N.P. acknowledge partial support from NASA/Swift Cycle 11 GI via grant NNX16AC12G. M.M.K. acknowledges partial support from the GROWTH project funded by the NSF under Grant #1545949. N.M. acknowledges support from the TTU Clark Scholars program. A.G.-Y. acknowledges support from the European Union FP7 programme through ERC grant #307260, the Quantum universe I-Core program by the Israeli Committee for Planning and Budgeting and the ISF; by Minerva and ISF grants; and by Kimmel and YeS awards. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Intermediate Palomar Transient Factory project is a scientific collaboration among the California Institute of Technology, Los Alamos National Laboratory, the University of Wisconsin, Milwaukee, the Oskar Klein Center, the Weizmann Institute of Science, the TANGO Program of the University System of Taiwan, and the Kavli Institute for the Physics and Mathematics of the universe. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Published - Palliyaguru_2016_ApJL_829_L28.pdf
Submitted - 1608.06518v2.pdf