Multiwavelength Studies of HER X-1

Details Multiwavelength Studies of HER X-1 Multiwavelength Studies of HER X-1

Jan 1996

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996umd..reptq....v&link_type=abstract

Technical Report, Maryland Univ. College Park, MD United States Dept. of Astronomy.

Astronomy and Astrophysics

Astronomy

Pulsars, X Ray Binaries, Spectral Emission, Ultraviolet Emission, X Ray Spectra, Accretion Disks, Stellar Mass Accretion, Rosat Mission, Companion Stars, Precession

Scientific paper

The ROSAT observations were part of an extensive multiwavelength campaign of the X-ray, pulsar system Her X-1/HZ Her conducted in 1993 August. The source was found in an anomalous low state detected only once before. Characteristics observed during anomalous low states include a substantial, unexpected drop in flux at X-ray energies, with no change in absorbing column density; an increase in the pulse period from the previous measurement, contrary to the usual spin-up; no pulsed emission above 0.9 keV; and optical fluxes that continued to show 1.7 day modulation attributed to X-ray heating of the companion star. The 1993 campaign also detected a significant reduction in UV flux during eclipse ingress and egress. Comprehensive modeling of the ultraviolet and optical continuum flux suggests that the ultraviolet and optical lightcurves can be reproduced by assuming variations in mass-accretion rate alone; however, changes in accretion rate are insufficient to account for the observed drop in X-ray flux. Shifts in disk inclination angle and changes in mass accretion rate can consistently explain the observed changes in X-ray, ultraviolet, and optical fluxes. The changes in mass accretion rate and disk inclination angle may be related to shifts in the 35-day precession period, with the average mass accretion rate corresponding to the average 35-day period. The rapid fluctuations in soft X-ray flux observed several times during the campaign may be caused by rapid variation of the mass accretion rate. To date a total of eight publications (refereed papers and conference reports) have resulted utilizing data obtained in connection with this grant, a ninth is in preparation. These publications are listed in this report.

Affiliated with

Also associated with

No associations

Rating

Multiwavelength Studies 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 Multiwavelength Studies of HER X-1, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiwavelength Studies of HER X-1 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1130231