ATel #10428; Thomas J. Maccarone (Texas Tech University), Arash Bahramian (Michigan State), Craig Heinke, Aarran Shaw, Greg Sivakoff (Alberta), Jamie Kennea (Penn State), Rudy Wijnands, Nathalie Degenaar (Amsterdam), Jay Strader (MSU), Jean in 't Zand (SRON), Erik Kuulkers (ESA), Deepto Chakrabarty (MIT)
on 25 May 2017; 18:23 UT
Credential Certification: Tom Maccarone (email@example.com)
Subjects: X-ray, Black Hole, Neutron Star, Transient
We observed Swift J1752339-290952 (ATel #10422) with Chandra with ACIS-S via a Director's Discretionary Time program. The data were taken starting on 2017-05-25 at 3:22:23 TT for ~8 ks. Eight photons were detected, indicating that the source has faded by a factor of several hundred since the original reported detection. The centroid position is RA 17:52:33.903 (h:m:s) DEC -29:09:47.95 (d:m:s), in J2000 coordinates, with the uncertainties likely to be dominated by the boresight correction and hence to be about 0.5".
The only star catalogued in Vizier that is within 3" is 1.7" away, with a UCAC5 position of RA=17:52:33.78, Dec=-29:09:47.4 in the same coordinate system as above (Zacharias et al. 2017, AJ, 153, 166). This star shows an infrared excess and blue colors (Zacharias et al. 2005, NOMAD catalog), which may make it consistent with being a Be star. The hardness of the X-ray spectrum reported earlier and the relatively rapid decay of the outburst are consistent with expectations for Be X-ray binary outbursts, but there would have to be an abnormally large boresight correction for this field for this star to be the real counterpart.
We thank the Chandra Director's office for approving this project in director's discretionary time.