TITLE:   GCN CIRCULAR
NUMBER:  21686
SUBJECT: LIGO/Virgo G298048: Pierre Auger Observatory neutrino follow-up
DATE:    17/08/25 08:13:23 GMT
FROM:    Jaime Alvarez-Muniz at Pierre Auger Observatory  <jaime.alvarezmuniz@gmail.com>

J. Alvarez-Muniz, F. Pedreira, E. Zas (Univ. Santiago de Compostela, Spain),
K. H. Kampert & M. Schimp (Bergische Universitat, Wuppertal, Germany)
on behalf of the Pierre Auger Collaboration.

In response to:
LIGO/Virgo GW trigger G298048
(GCN #21505 and #21509 ,T0=2017-08-17 at 12:41:04.527 UTC)

We searched for Ultra-High-Energy (UHE) neutrinos with energies
above ~ 1e17 eV in data collected with the Surface Detector (SD)
of the Pierre Auger Observatory in a [-500,500] second interval
about the LIGO-Virgo trigger G298048 as well as 1 day after it.

The field of view (fov) where the SD of Auger is sensitive to UHE
neutrinos (corresponding to inclined directions with respect to the
vertical relative to the ground) was FULLY COINCIDENT with the
LIGO+Virgo 90% localization region (GCN #21513 bayestar-HLV.fits.gz)
at the time T0 of the merger alert as well as with the optical
counterpart detected by the Swope telescope (GCN #21529).
Also the 90% CL Fermi GBM trigger 170817.529 contour (GCN #21506)
at the trigger time was largely overlapping with the Auger fov.

NO events survived the cuts applied to reject the background due
to UHE Cosmic Rays i.e. NO neutrino candidates were detected.

-------
The Pierre Auger Observatory is an UHE Cosmic Ray detector
located in the Mendoza Province in Argentina. It consists of
an array of Water Cherenkov detectors spread over a total surface
of 3000 km^2 arranged in a triangular grid of 1.5 km side as well
as Fluorescence telescopes and other systems
(see 10.1016/j.nima.2015.06.058 for more information).
For neutrino searches from GW events with Auger, please refer to:
https://journals.aps.org/prd/pdf/10.1103/PhysRevD.94.122007