Re: Wings of Chandra Point Spread Function

From: Dan Schwartz (das@head-cfa.harvard.edu)
Date: Wed Oct 18 2000 - 18:56:56 EDT


I made an egregious error in the figure I sent yesterday, and
another in the text.

Thanks to Henric's inquiries I have investigated and fixed them.

The figure intended to plot the mid-area point of each bin, i.e., .707
of the distance to the next bin. But instead of adding .707 of a bin,
I had multiplied the bin coordinate by 0.7 so that, e.g., the point
which should have been at 48.5 arcsec appeared at ~35arcsec.

In the plot attached below, I plot the point 30% above the left
edge of each bin, giving an "eyeball" compensation for the
steeply falling wing-spread function.

Second correction is that the points for 3C273 are all statistically
signficant. They are still at about 6 sigma even for the furthest
point at each binning resolution.

Apologies for the inconveniences, and thanks for the queries which led
me to debug the problems.

Dan

> Dear Dan
>
> Thank you very much for the reply. Your plot is very interesting!
>
> Some questions:
> * The 3C279 results look good out to radii of 34''. Are the error bars on
        ^3C273 is the source.

> all points above 20'' huge?
> * All sources were located near the aimpoint of ACIS S?
        All sources were near on-axis, but the aimpoint may
be somewhat different.

>
> I will run MARX simulations and mail you the results as soon as possible.
>
> Henric
>
> ** Henric Krawczynski, email: krawcz@astro.yale.edu, tel: (203) 432 5796
> Astronomy Dept.-Yale University-P.O. Box 208101-New Haven, CT 06520-8101 USA
>
>
>
>
>




-------------------------------------------------------
Dan Schwartz, MS #3
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
-------------------------------------------------------


-------------------------------------------------------
Dan Schwartz, MS #3
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
-------------------------------------------------------


-------------------------------------------------------
Dan Schwartz, MS #3
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
-------------------------------------------------------


-------------------------------------------------------
Dan Schwartz, MS #3
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
-------------------------------------------------------


-------------------------------------------------------
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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