Swift Observations of the Ultra-compact Binary 4U 1850-087
Abstract
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.
- Publication:
-
The Astronomer's Telegram
- Pub Date:
- May 2008
- Bibcode:
- 2008ATel.1551....1P
- Keywords:
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- X-ray;
- Binaries;
- Neutron Stars;
- Transients