Hard X-ray timing observation of the Crab Pulsar and Cygnus X-1

Details Hard X-ray timing observation of the Crab Pulsar and Cygnus X-1 Hard X-ray timing observation of the Crab Pulsar and Cygnus X-1

Jan 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...421..269u&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 421, no. 1, p. 269-275

Physics

10

Light Curve, Periodic Variations, Pulsars, Spectral Emission, Spectrum Analysis, Stellar Radiation, Statistical Analysis, Stellar Physics

Scientific paper

Results of a timing analysis of the Crab Pulsar and Cygnus X-1 are presented. These two strong Galactic sources were observed on 1985 August 5 with the POKER experiment in the energy range 15-130 keV. The spectral behavior, showing a canonical spectrum for the Crab and a low emission state for Cyg X-1, has already been reported in Ubertini et al. (1991a). The phase-averaged Crab pulsar emission is well represented by a power law of photon index GAMMA = 2.06 and a 30 keV intensity of 1.04 x 10-3 ph sq cm/s/keV. The pulsar light curve shows a wide first peak (2.4 ms FWHM) if compared with similar high statistics observations in the same energy range. For Cyg X-1 we find no indication of flaring activity nor any other strong time variability in our observation. Nevertheless, the 15-100 keV data are inconsistent with steady state emission at a statistical confidence level greater than 99%. Our data also confirm the presence of the recently reported quasi-periodic oscillations (QPO), showing different frequencies at different times and centered in our observation at 0.013 Hz and 0.040 Hz and modulating a few percent of the total flux. An upper limit of 24% on chaotic variability at 0.24-14 Hz is also set.

Affiliated with

Also associated with

No associations

Rating

Hard X-ray timing observation of the Crab Pulsar and Cygnus 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 Hard X-ray timing observation of the Crab Pulsar and Cygnus X-1, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hard X-ray timing observation of the Crab Pulsar and Cygnus X-1 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-866102