Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-09-27
Astronomy and Astrophysics
Astrophysics
24 pages, 12 figures. To appear in ApJ 529 #2, 1 Feb 2000
Scientific paper
10.1086/308308
We report on our analysis of a large sample of energy dependent pulse profiles of the X-ray binary pulsar Hercules X-1. We find that all data are compatible with the assumption of a slightly distorted magnetic dipole field as sole cause of the asymmetry of the observed pulse profiles. Further the analysis provides evidence that the emission from both poles is equal. We determine an angle of 20 deg between the rotation axis and the local magnetic axis. One pole has an offset of 5 deg from the antipodal position of the other pole. The beam pattern shows structures that can be interpreted as pencil- and fan-beam configurations. Since no assumptions on the polar emission are made, the results can be compared with various emission models. A comparison of results obtained from pulse profiles of different phases of the 35-day cycle indicates different attenuation of the radiation from the poles being responsible for the change of the pulse shape during the main-on state. These results also suggest the resolution of an ambiguity within a previous analysis of pulse profiles of Cen X-3, leading to a unique result for the beam pattern of this pulsar as well. The analysis of pulse profiles of the short-on state indicates that a large fraction of the radiation cannot be attributed to the direct emission from the poles. We give a consistent explanation of both the evolution of the pulse profile and the spectral changes with the 35-day cycle in terms of a warped precessing accretion disk.
Blum Stefan
Kraus Ute
No associations
LandOfFree
Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of Her X-1 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 Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of Her X-1, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of Her X-1 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-59387