TITLE:   GCN CIRCULAR
NUMBER:  20523
SUBJECT: LIGO/Virgo G270580: Swift-XRT follow-up of PS17yt
DATE:    17/01/25 09:30:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester), J.A. Kennea (PSU), S.D. Barthelmy
(NASA/GSFC), A.P. Beardmore (U. Leicester), A.A. Breeveld (UCL-MSSL),
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), N. Gehrels (NASA/GSFC), P. Giommi (ASI), C. Gronwall
(PSU), H.A. Krimm (CRESST/GSFC/USRA), N.P.M. Kuin (UCL-MSSL), A.Y. Lien
(GSFC/UMBC), D. Malesani (DARK/NBI), F.E. Marshall (NASA/GSFC), A.
Melandri (INAF-OAB), B. Mingo (U. Leicester),  J.A. Nousek (PSU), S.R.
Oates (U. Warwick), P.T. O'Brien (U. Leicester), J.P. Osborne (U.
Leicester), C. Pagani (U. Leicester), K.L. Page (U.Leicester), 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:

Swift observed the location of the bright transient PS17yt (Chambers et 
al., LVC Circ. 20512) for 3ks, from 17:25:27 UT to 19:27:07 UT on 2017 
January 24.

No X-ray source is detected at the location of PS17yt. The 3-sigma upper 
limit is 3.1e-3 ct/sec. For a typical AGN power-law spectrum (NH=3e20, 
Gamma=1.7) this corresponds to an observed flux of 1.28e-13 erg cm^-2 s^-1.

This circular is an official produce of the Swift-XRT team.