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ATEL # 1511; S. B. Moore, J. M. Miller (University of Michigan)
on 6 May 2008; 19:37 UT
Password Certification: Jon Miller (email@example.com)
Subjects: X-ray, Binaries, Black Holes
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.