XMM-Newton observation of M101 ULX-1
ATel #409; A. K.H. Kong (MIT)
on 11 Feb 2005; 00:52 UT
Credential Certification: Albert Kong (akong@cfa.harvard.edu)
Subjects: X-ray, Binary, Black Hole, Variables
We report XMM-Newton TOO observation of the recent outburst of M101 ULX-1 (CXOU J140332.3+542103; ATEL #374). The observation was taken on 8 January 2005 with an exposure time of 32 ks. With about 20 ks useful data, there are about 1200 counts in EPIC-pn for spectral fitting. The spectrum is very soft and there is no significant X-ray emission above 1 keV. The spectrum has a peak at around 0.4-0.5 keV and can be fitted with an absorbed blackbody model (N_H=1.9e21 cm^-2, kT=56 eV). The absorbed 0.3-2.5 keV luminosity is 4.5e38 ergs/s (d=6.7 Mpc), a factor of 3 lower than the Chandra observation taken on 1 January 2005. The unabsorbed 0.3-7 keV luminosity of the source is about 5.9e39 ergs/s during the XMM-Newton observation, similar to the initial decline stage of the previous outburst in 2004 July (Kong et al. 2004, ApJ, 617, L49). The source spectrum also changed from a quasisoft (Di Stefano and Kong 2004, ApJ, 609, 710) shape (kT=166 eV; ATEL #374) back to a supersoft spectrum (kT=60 eV)
during the decline.
