[vsnet-grb-info 24678] LIGO/Virgo S200115j High Rank XRT sources are spurious

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26777
SUBJECT: LIGO/Virgo S200115j High Rank XRT sources are spurious
DATE:    20/01/15 17:52:12 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

P.A. Evans (U. Leicester) reports

Recently a significant number of GCN/COUNTERPART notices have been issued by the automated Swift/XRT analysis reporting sources with ranks 1 or 2, i.e. a strong candidate to be the counterpart. Unfortunately, none of these are real. Due to a period of unusually high XRT temperature, the background in some of our GW follow up is very elevated and inhomoegnious which has given rise to these spurious sources with apparently high fluxes. We apologise for any inconvenience.

Users are reminded that all COUNTERPART notices are preliminary - they are produced from automated systems, pre human vetting; sources identified once manually confirmed will be made available through the website: https://www.swift.ac.uk/LVC/ and naturally, should we identify something which we consider of significant interest we shall of course confirm it in a circular at the earliest possible opportunity.

We have disabled the distribution of the counterpart notices for S200115j due to these issues.