Swift Observations of the ULX NGC 5408 X-1
ATel #1511; S. B. Moore, J. M. Miller (University of Michigan)
on 6 May 2008; 19:37 UT
Credential Certification: Jon Miller (jonmm@umich.edu)
Subjects: X-ray, Binary, Black Hole
We report on the ultra-luminous X-ray (ULX) source NGC 5804 X-1 using several Swift
XRT observations. These observations occurred on 2008 April 9, April 11, April 15,
April 18, and April 25. Using XSPEC v11 and fitting the spectra with a power-law
model in the 0.3-10.0 keV band (and freezing the absorbing column density along the
line of sight at 7 E+20 cm^-2), we obtained power-law indices ranging from 1.8 +/-
0.7 to 2.4 +/- 0.4 (90 percent confidence errors). The flux values ranged from 2.2
+/- 0.3 E-12 cgs to 2.7 +/- 0.2 E-12 cgs. The calculated luminosity (assuming a
distance of 4.8 Mpc) ranged from 6 +/- 2 E+39 erg/s to 7 +/-2 E +39 ergs/s. Thus, within
the limits of our sensitivity, no significant variation in the spectrum or
luminosity of the source was observed.
