Fitting the X-ray spectra of thermal neutron stars with the ATM model
Abstract
In this poster we present new results fitting Chandra ACIS and LETG/HRC-S spectra of the Cas A X-ray point source and the archival observation of isolated neutron star RXJ185635-3754 to H, H-He, Si-ash, and Fe atmosphere models calculated with our ATM model atmosphere code. In the case of the Cas A XPS, we find our atmosphere models fit significantly better than blackbody fits, although a wide range of radii are formally permitted (see analysis for details). The best fit H model is consistent with a neutron star of radius ∼ 6.5 km, but with a radiating area scale size of only ∼ 3km, consistent with a hot spot geometry. We also show the effects of the Cas A SNR on the XPS spectrum. In the case of RXJ1856 we find H and Fe spectra to provide unacceptable fits to the X-ray and optical data, but we do find physically plausible results with Si-ash fits and a fast, rotating neutron star.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AAS...20114405S