Increase in the X-ray flux of AT2018cow
ATel #11801; L. E. Rivera Sandoval, T. Maccarone (Texas Tech University)
on 30 Jun 2018; 23:00 UT
Credential Certification: Liliana Rivera Sandoval (liliana.rivera@ttu.edu)
Subjects: X-ray, Gamma-Ray Burst, Supernovae, Transient
Referred to by ATel #: 11843
We report on Swift/XRT observations of the optical transient AT2018cow/ATLAS18qqn (ATel #11727).
Observations of the target taken on 29 June 2018 showed an increase in the X-ray flux compared to previous observations (ATel #11761), reaching a maximum flux of 1.8 +/- 0.7 e-11 erg/s/cm2 when we fit an absorbed power law model using wilm abundances (Wilms et al. 2000) and vern cross-sections (Verner et al. 1996) to the X-ray spectrum in the 0.3-10 keV energy band. The photon index at that flux was 1.2 +/- 0.8 and nh = 1.1 +/- 49.2 e20 cm-2. The most recent Swift observations, performed on 30 June 2018 (17:17:14-17:39:53 UT), suggest that the object has faded to a minimum X-ray flux of 6.05 +/- 1.32 e -12 erg/s/cm2 with nh=6.9 +/- 11.6 e20 cm-2 and photon index=1.7 +/- 0.4.
More Swift observations are planned. We thank the Swift team for approving and executing our ToO.