Outburst of the Ultraluminous Supersoft X-ray Source in M101
ATel #306; A. K.H. Kong (Harvard-Smithsonian Center for Astrophysics)
on 14 Jul 2004; 08:11 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Albert Kong (akong@cfa.harvard.edu)
Subjects: X-ray, Binary, Black Hole, Transient
Referred to by ATel #: 311
We report further Chandra observations of the ultraluminous supersoft X-ray source in M101, currently in outburst (ATEL #305). Data taken on 2004 July 6 (for 28 ks) and 2004 July 8 (for 54 ks) show that the source is in high/supersoft state. Preliminary analysis shows that the energy spectrum of the first observation can be fit with an absorbed blackbody model (N_H=2.8e21 cm^-2, kT=105 eV) plus two absorption edges at 0.66 keV and 0.87 keV. The 0.3-7 keV luminosity is 1e40 erg/s and the bolometric luminosity is 1.7e40 erg/s (d=6.7 Mpc). During the second observation on July 8, the energy spectrum can be fit with an absorbed blackbody model (N_H=1.4e21 cm^-2, kT=56 eV) plus two absorption edges at 0.33 keV and 0.56 keV. The 0.3-7 keV luminosity is 8e39 erg/s and the bolometric luminosity is 8e40 erg/s. During both observations, the source exhibits significant timing variability. The spectra of the two observations can be obtained at http://hea-www.harvard.edu/~akong/SSSjuly6.ps and http://hea-www.harvard.edu/~akong/SSSjuly8.ps.
