Astronomy and Astrophysics – Astrophysics
Scientific paper
Apr 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007ap%26ss.308..259z&link_type=abstract
Astrophysics and Space Science, Volume 308, Issue 1-4, pp. 259-265
Astronomy and Astrophysics
Astrophysics
6
Scientific paper
Recent Chandra and XMM-Newton observations of a number of X-ray “dim” pulsating neutron stars revealed quite unexpected features in the emission from these sources. Their soft thermal spectrum, believed to originate directly from the star surface, shows evidence for a phase-varying absorption line at some hundred eVs. The pulse modulation is relatively large (pulsed fractions in the range ˜8 35% in amplitude), the pulse shape is often non-sinusoidal, and the hard X-ray color appears to be anti-correlated in phase with the total emission. Moreover, the prototype of this class, RX J0720.4-3125, has been found to undergo rather sensible changes both in its spectral and timing properties over a timescale of a few years. By modeling the light curves of two sources, RBS 1223 and RX J0720.4-3125, it has been found evidence for two hot regions located at a slightly non antipodal direction. All these new findings are difficult to reconcile with the standard picture of a cooling neutron star endowed with a purely dipolar magnetic field. Here we present more realistic models of surface emission, where the effects of different neutron star thermal and magnetic surface distributions are accounted for. We show how a star-centered field made of a dipolar and a quadrupolar component can influence the properties of the observed light curves and we present results that account self-consistently for toroidal and poloidal crustal field configurations.
No associations
LandOfFree
Neutron star surface emission: Beyond the dipole model does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Neutron star surface emission: Beyond the dipole model, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Neutron star surface emission: Beyond the dipole model will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1682391