Fermi GBM observations of LIGO gravitational-wave event GW150914

Connaughton, V. et al. (2016) Fermi GBM observations of LIGO gravitational-wave event GW150914. Astrophysical Journal, 826(1), L6. (doi: 10.3847/2041-8205/826/1/L6)

Abstract

With an instantaneous view of 70% of the sky, the Fermi Gamma-ray Burst Monitor (GBM) is an excellent partner in the search for electromagnetic counterparts to gravitational-wave (GW) events. GBM observations at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914 reveal the presence of a weak transient above 50 keV, 0.4 s after the GW event, with a false-alarm probability of 0.0022 (2.9σ). This weak transient lasting 1 s was not detected by any other instrument and does not appear to be connected with other previously known astrophysical, solar, terrestrial, or magnetospheric activity. Its localization is ill-constrained but consistent with the direction of GW150914. The duration and spectrum of the transient event are consistent with a weak short gamma-ray burst (GRB) arriving at a large angle to the direction in which Fermi was pointing where the GBM detector response is not optimal. If the GBM transient is associated with GW150914, then this electromagnetic signal from a stellar mass black hole binary merger is unexpected. We calculate a luminosity in hard X-ray emission between 1 keV and 10 MeV of ${1.8}_{-1.0}^{+1.5}\times {10}^{49}$ erg s−1. Future joint observations of GW events by LIGO/Virgo and Fermi GBM could reveal whether the weak transient reported here is a plausible counterpart to GW150914 or a chance coincidence, and will further probe the connection between compact binary mergers and short GRBs.

• Item Type: Articles
• Additional Information: The GBM project is supported by NASA. Support for the German contribution to GBM was provided by the Bundesministerium für Bildung und Forschung ( BMBF ) via the Deutsches Zentrum für Luft und Raumfahrt ( DLR ) under contract number 50 QV 0301. A.v.K. was supported by the Bundesministeriums für Wirtschaft und Technologie ( BMWi ) through DLR grant 50 OG 1101. A.G. and L.S. are funded through the NASA Postdoctoral Fellow- ship Program. O.J.R. acknowledges support from Science Foundation Ireland under grant No. 12 / IP / 1288. J.V. was supported by STFC grant, ST / K005014 / 1. N.C. acknowledges NSF grant, PHY-1505373.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Veitch, Dr John
• Authors: Connaughton, V., Burns, E., Goldstein, A., Blackburn, L., Briggs, M.S., Zhang, B.-B., Camp, J., Christensen, N., Hui, C.M., Jenke, P., Littenberg, T., McEnery, J.E., Racusin, J., Shawhan, P., Singer, L., Veitch, J., Wilson-Hodge, C.A., Bhat, P.N., Bissaldi, E., Cleveland, W., Fitzpatrick, G., Giles, M.M., Gibby, M.H., von Kienlin, A., Kippen, R.M., McBreen, S., Mailyan, B., Meegan, C.A., Paciesas, W.S., Preece, R.D., Roberts, O.J., Sparke, L., Stanbro, M., Toelge, K., and Veres, P.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Astrophysical Journal
• Publisher: American Astronomical Society
• ISSN: 0004-637X
• ISSN (Online): 1538-4357
• Published Online: 13 July 2016
• Copyright Holders: Copyright © 2016 The American Astronomical Society
• First Published: First published in Astrophysical Journal 826(1):L6
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher