Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory

TL;DR

This study used the Pierre Auger Observatory to search for ultrahigh-energy neutrinos from gravitational wave events GW150914 and GW151226, finding no candidates and setting constraints on neutrino emission from these black hole mergers.

Contribution

First search for ultrahigh-energy neutrinos associated with GW black hole mergers using the Pierre Auger Observatory, providing constraints on neutrino emission.

Findings

No neutrino candidates detected in the search window.

Constraints placed on the energy radiated in ultrahigh-energy neutrinos.

Results improve understanding of neutrino emission from black hole mergers.

Abstract

On September 14, 2015 the Advanced LIGO detectors observed their first gravitational-wave (GW) transient GW150914. This was followed by a second GW event observed on December 26, 2015. Both events were inferred to have arisen from the merger of black holes in binary systems. Such a system may emit neutrinos if there are magnetic fields and disk debris remaining from the formation of the two black holes. With the surface detector array of the Pierre Auger Observatory we can search for neutrinos with energy above 100 PeV from point-like sources across the sky with equatorial declination from about -65 deg. to +60 deg., and in particular from a fraction of the 90% confidence-level (CL) inferred positions in the sky of GW150914 and GW151226. A targeted search for highly-inclined extensive air showers, produced either by interactions of downward-going neutrinos of all flavors in the atmosphere or by the decays of tau leptons originating from tau-neutrino interactions in the Earth's crust (Earth-skimming neutrinos), yielded no candidates in the Auger data collected within $\pm 500$ s around or 1 day after the coordinated universal time (UTC) of GW150914 and GW151226, as well as in the same search periods relative to the UTC time of the GW candidate event LVT151012. From the non-observation we constrain the amount of energy radiated in ultrahigh-energy neutrinos from such remarkable events.