TITLE:   GCN CIRCULAR
NUMBER:  21786
SUBJECT: LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
DATE:    17/09/02 16:57:54 GMT
FROM:    Raffaella Margutti at Northwestern U  <rafmargutti@gmail.com>

W. Fong, R. Margutti (Northwestern), D. Haggard (McGill) report on behalf
of a larger collaboration:


We analyzed observations of the field of the EM counterpart to LVC trigger
G298048 with the Chandra X-ray Observatory (CXO; ObsID 20728, PI Troja)
starting on 2017 Sep 1.640 UT (15.1 days after the LVC trigger time). In 50
ksec of observations, we clearly detect X-ray emission at the location of
the optical transient (Coulter et al., LVC GCN 21529; Allam et al., LVC GCN
21530; Sheng Yang et al., LVC GCN 21531; Chambers et al., LVC GCN 21553),
suggesting continued X-ray emission from the transient (Troja et al., LVC
GCN 21765). Extended emission from the host galaxy (Margutti et al., LVC
GCN 21648; Evans et al., LVC GCN 21612) is still detected. We also note the
presence of a third X-ray source in the Swift/XRT error circle (Evans et
al., LVC GCN 21612; RA,Dec = 13:09:48.014,-23:23:04.93), that has not been
previously reported.

We thank Belinda Wilkes and the entire Chandra team for their great support
with these observations.

[GCN OPS NOTE(03sep17): This circular (21786) completely replaces 21784
(whose text was the result of a copy-paste mistake).]