ASCA measurements of the grain-scattered X-ray halos of eclipsing massive X-ray binaries: VELA X-1 and Centaurus X-3

Details ASCA measurements of the grain-scattered X-ray halos of eclipsing massive X-ray binaries: VELA X-1 and Centaurus X-3 ASCA measurements of the grain-scattered X-ray halos of eclipsing massive X-ray binaries: VELA X-1 and Centaurus X-3

Nov 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...436l...5w&link_type=abstract

Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 436, no. 1, p. L5-L8

Astronomy and Astrophysics

Astrophysics

25

Eclipsing Binary Stars, Halos, Massive Stars, Pulsars, X Ray Binaries, X Ray Scattering, Imaging Spectrometers, Interstellar Matter, Light Curve

Scientific paper

We have measured the decaying dust-scattered X-ray halo of Cen X-3 during its binary eclipse with the ASCA solid-state imaging spectrometer (SIS). The surface brightness profile (SBP) of the image in the low-energy band (0.5-3 keV) lies substantially above the point-spread function (PSF) of the X-ray telescope, while the SBP in the high-energy band (5-10 keV) exhibits no significant deviation. By contrast, the SBPs of Vela X-1 during its eclipse are consistent with the PSF in both the low- and high-energy bands -- strong evidence that a dust halo is indeed present in Cen X-3. Accordingly, we modeled the SBP of Cen X-3 taken from six consecutive time segments under the principal assumptions that the dust is distributed uniformly along a segment of the line of sight, the grains have a power-law size distribution, and the low-energy source flux was the same function of orbital phase before as during our observation. The best-fit set of parameters included a grain density value of 1.3 g/cu cm, substanially less than the density of 'astronomical silicate.' This result supports the idea that interstellar grains are 'fluffy' aggregates of smaller solid particles. We attribute the failure to detect a halo of Vela X-1 during its eclipse phase to extended strong circumsource absorption that probably occurred before the eclipse and allowed the halo to decay away before the observation began.

Affiliated with

Also associated with

No associations

Rating

ASCA measurements of the grain-scattered X-ray halos of eclipsing massive X-ray binaries: VELA X-1 and Centaurus X-3 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 ASCA measurements of the grain-scattered X-ray halos of eclipsing massive X-ray binaries: VELA X-1 and Centaurus X-3, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ASCA measurements of the grain-scattered X-ray halos of eclipsing massive X-ray binaries: VELA X-1 and Centaurus X-3 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1022710