[vsnet-grb-info 24692] LIGO/Virgo S200114f: Possible X-ray transient

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26791
SUBJECT: LIGO/Virgo S200114f: Possible X-ray transient 
DATE:    20/01/16 19:14:59 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U.
Toronto), S.D. Barthelmy (NASA/GSFC), A.P. Beardmore (U. Leicester),
M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), P. Brown (TAMU),
D.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), G.
Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),
V. D'Elia(ASDC), S.W.K. Emery (UCL-MSSL), P. Giommi (ASI), C. Gronwall
(PSU), D. Hartmann (U. Clemson), H.A. Krimm (CRESST/GSFC/USRA), N.J.
Klingler (PSU), N.P.M. Kuin (UCL-MSSL), A.Y. Lien (GSFC/UMBC), F.E.
Marshall (NASA/GSFC), A. Melandri (INAF-OAB), J.A. Nousek (PSU), S.R.
Oates (U. Birmingham), P.T. O'Brien (U. Leicester), J.P. Osborne (U.
Leicester), C. Pagani (U. Leicester), K.L. Page (U.Leicester), M.J.Page
(UCL-MSSL), D.M. Palmer (LANL), M. Perri (ASDC), J.L. Racusin
(NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M.H. Siegel (PSU), G.
Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP) report on behalf of
the Swift team:


We have carried out further observations of the rank 2 source (referred to as Source 2) in GCN 26787. This source,hereafter, Source S200114f_X2 has not faded between our observations, however it is detected with a 0.3-10 keV count rate of 0.069 +/- 0.0064 ct/sec.

A spectrum created from the recent XRT data can be modelled with a power-law with photon index 1.4 (+0.4, -0.3). Using this model, a 3-sigma RASS upper limit at this location translates to 0.038 ct/sec in XRT. The recent detectionis therefore nearly 5-sigma above the upper limit from RASS, accounting for the spectral shape.

As reported in GCN 26787, this source is positionally coincident with a candidate AGN, and therefore this rise in flux may indicate nothing more than AGN activity, however it could also indicate a transient source occuring in the AGN. Our position uncertainty does not allow us to confirm whether this source is in the nuclear of the WISE galaxy.

Further observations are therefore strongly encouraged.

The source position is 

    RA: 110.3641 ( = 07h 21m 27.38s) J2000
    Dec:  +17.0360 ( = +17d 02' 09.6") J2000
    Error:  7.0 arcsec, (radius, 90% confidence).