GCN Circular 1049
Subject
SGR 1900+14: Detection of extended X-ray emission
Date
2001-04-26T00:05:20Z (23 years ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
D. W. Fox and D. L. Kaplan (Caltech) report:
"Analysis of data from the 22 April 2001 Chandra observation (GCN
1046, 1047), barycenter-corrected with the preliminary CXC ephemeris,
reveals that the source emission is pulsed at a period of P =
5.17288(5) s with a pulse strength of 14.3(2)% RMS that remains
constant (within errors) throughout the observation. Separation of
the source photons into "on-pulse" and "off-pulse" components of 1/3
cycle each reveals that the off-pulse spatial distribution is
significantly broader than the on-pulse distribution. Since the
observation is taken in continuous-clocking mode, we can only make
this determination in one dimension. Nonetheless, the sigma-widths of
the one-dimensional Gaussian PSFs are 0.98(1) arcsec for on-pulse
photons and 1.08(2) arcsec for off-pulse photons, different at
>5-sigma level. We attribute this difference in widths to the
presence of an underlying X-ray nebula."