X-ray Emission likely not from Supernova 2017egm
ATel #10531; Dirk Grupe (Morehead State University), Subo Dong (KIAA-PKU), Jose L. Prieto (Universidad Diego Portales), & David Pooley (Trinity University)
on 26 Jun 2017; 01:50 UT
Credential Certification: Dirk Grupe (firstname.lastname@example.org)
Subjects: X-ray, Supernovae
We report on new Swift observations of the field of supernova 2017egm (Delgado et al, TNS Astronomical Transient Report No 11679;
->TNS; ATel #10498)
and found that the X-ray emission reported in ATel \#10499 (Grupe et al.) are likely not associated with supernova 2017egm. The new Swift observations were performed 2017-June-16 - June-24. Adding all observation (including those reported in ATel \#10499) together the field of 2017egm was observed for 26048s. The count rate of the X-ray source can be measured to be (1.04+0.22-0.20)e-3 counts/s in the Swift XRT in the 0.3-10 keV band, which is approximately 5e-17 W m^-2 (5e-14 ergs s^-1 cm^-2). This count rate is consistent with the count rate reported in ATel \#10499 and does not suggest a variation of the X-ray source.
The X-ray position of the X-ray source can be determined using the online X-ray product tool at the University of Leicester website (http://www.swift.ac.uk/user_objects/; Evans et al. 2007, Goad et al. 2007) to be RA-2000 = 10 19 05.04, Dec-2000 = 46 27 17.0 with an uncertainty of 5.4". This position is 6.7" away from the optical position of supernova 2017egm and 2.1" from the position of NGC 3191.
We conclude that the X-rays are more likely associated with the star forming region of NGC 3191 than with supernova 2017egm.
We would like to thank Brad Cenko for approving further Swift observations of 2017egm and the Swift team for their continuous support of these observations.
This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.