A BeppoSAX observation of the massive X-ray binary 4U 1700-37
Abstract
A 0.5-200 keV BeppoSAX spectrum of the non-pulsating high-mass X-ray binary 4U 1700-37 is presented. The spectrum is well characterized by the standard accreting pulsar model of an absorbed power-law with a photon index of 1.07 +/- (0.02) _{0.03}, sharply modified by an exponential cutoff above 5.9 +/- 0.2 keV. The e-folding energy of the cutoff is 23.9 +/- 0.5 keV. A soft bremsstrahlung component with a temperature of 0.2 +/- 0.1 keV is also required, together with a narrow iron line at 6.5 keV. Both continuum components are absorbed by a column of (5.1 +/- 0.2)x 10(22) atom cm(-2) . There is some evidence for the presence of a broad cyclotron absorption feature at ~ 37 keV, although we cannot exclude the possibility that this is due to an incorrect modeling of the continuum, or instrumental effects. The hypothesis that the compact object is a neutron star rather than a black hole seems most likely.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1999
- DOI:
- 10.48550/arXiv.astro-ph/9904349
- arXiv:
- arXiv:astro-ph/9904349
- Bibcode:
- 1999A&A...349..873R
- Keywords:
-
- STARS: INDIVIDUAL: 4U 1700-37 = HD 153919;
- STARS: NEUTRON;
- X-RAYS: STARS;
- Astrophysics
- E-Print:
- 4 pages. Accepted for publication in A&