> Dear Co-Users
>
> I am analyzing the data of a strong X-Ray source. After determining the
> spectrum of the source, I subtracted the Marx-estimate of the source
> emission from the data and a statistically highly significant residuum
> remains with an event excess at 15''-50'' angular distances from the
> source.
>
> Has anybody used in-flight data to compare the wings of the point spread
> function with the predictions of the Marx simulations?
Hi Henric, et al.
I have deduced the on-orbit wing spread using three bright quasars,
3C 273, PG1634+704, and PKS0637-752.
The energy range is 0.5 to 8 keV, events are grades 0,2,3,4,6.
The attached plot gives the counting rate, counts/(sec), which would be
measured in 1 pixel, IF the on-axis point source gave 1 count/sec. The
on-axis counting rate is the true measured count rate in ACIS-S (i.e.,
not the true incident rate counted by a perfect detector), but with
NO pile-up. Experimentally, such a no-pile up rate must be determined from
the read-out streak -- that is the key to the analysis!
I showed this in my talked at the Palermo Xray 2000 conference, and
it will be published in conference proceedings
"Analysis of the PKS0637-752 X-ray Jet System," by D. A. Schwartz et al.
Note that error bars (upper 2 sigma) appear only for PG1634. All results
are essentially noise beyond 20 arcsec radius. 3C273 is
still dominated by pile up at less than 5 arcsec from the core.
I plot points at the area midpoint of either 5 arcsec or 2 arcsec
bins. Since the scattering is steeply falling, this is an error: the
points should effectively be considered to be at smaller radial displacements.
If one treats them as a histogram, it should be okay.
I've never compared to MARX, so I would be interested to hear results.
Dan
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Dan Schwartz, Smithsonian Astrophysical Observatory
60 Garden St. Cambridge MA 02138, das@head-cfa.harvard.edu
phone: (617)495-7232 FAX: (617)495-7356
cell phone: (617)512-5627
pager: 800-759-8352 PIN 1636502; or e-mail 1636502@skytel.com
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