Swift Observations of the Ultra-compact Binary 4U 1850-087
ATel #1551; K. J. Perry, J. M. Miller, E. Cackett, (University of Michigan), D. Altamirano (University of Amsterdam)
on 30 May 2008; 13:45 UT
Credential Certification: Jon Miller (jonmm@umich.edu)
Subjects: X-ray, Binary, Neutron Star, Transient
We report on six observations of the ultra-compact X-ray binary 4U 1850-087 (P_orb = 21
min) in a rare high flux state, taken by Swift. Observations were made on 12,
14, 15, 16, 18, and 20 May 2008. Fits to the XRT spectra were made over the 0.5-10 keV
band, assuming a column density of 2.4 E+21. The
distance was assumed to be 6.8 kpc (Sidoli et al. 2004). The photon index ranged from 2.09 to 2.30, the
unabsorbed flux ranged from 2.55 E-10 to 6.0 E-10 cgs, and the luminosity ranged from 1.1
E+36 to 3.4 E+36 erg/s. A blackbody component was not required by the spectra, with an upper limit
flux of 1.5 E-10 cgs.
