New PSFs available for the ASCA GIS

["Ian M George, Code 668, NASA/GSFC, USA (Usque ad mortem bibendum)" <GEORGE@lheavx.gsfc.nasa.gov>]

   Point Spread Function datasets for the ASCA GIS available
   ---------------------------------------------------------

There are new images giving the Point Spread Function of the ASCA GIS
available in the Calibration Database on legacy.gsfc.nasa.gov. These
datasets have been provided by Keith Arnaud of the ASCA GOF. 

There are 11 new files within the directory:
	/caldb/data/asca/gis/bcf/psf/
one file for each of 11 different positions in the focal plane, with a 
naming scheme psf_*_*.fits. Each file contains 10 psf images appropriate 
for 10 different energy bands. Further information is provided in the 
README file within the above directory (and appended below).

Ian M George
HEASARC Caldb

----------------------------------------------------------------------------
README for ASCA GIS Point Spread Function datasets

This directory contains files containing PSF images for the ASCA GIS.
The file naming scheme is psf_X_Y.fits, where each file contains PSF
images for a given position in the focal plane, with X giving the 
off-axis angle (theta, in arcmins) and Y giving the azimuthal angle 
(phi, in degrees). The following positions are currently available:
	pos. 1: theta= 1.8 arcmin, phi= 5 deg
	pos. 2: theta= 3.8 arcmin, phi=10 deg
	pos. 3: theta= 6.0 arcmin, phi= 9 deg
	pos. 4: theta= 6.0 arcmin, phi=19 deg	
	pos. 5: theta= 8.1 arcmin, phi=34 deg
	pos. 6: theta=13.0 arcmin, phi= 0 deg
	pos. 7: theta=13.0 arcmin, phi=22 deg
	pos. 8: theta=13.0 arcmin, phi=40 deg
	pos. 9: theta=17.0 arcmin, phi= 0 deg
	pos.10: theta=17.0 arcmin, phi=18 deg
	pos.11: theta=17.0 arcmin, phi=39 deg

Each file contains 10 PSF images (the Primary Array + 9 IMAGE extensions)
appropriate for 10 different energy bands (1-2-3-4-5-6-7-8-9-10-12 keV).

Each image is 63 x 63 pixels, where 1 image pixel = 1 arcmin (= 4 GIS pixels), 
and were constructed from observations of Cyg X-1 using the GIS. 

In all cases:
- The peak brightness is at the center of the pixel (32,32). 
- The images are normalized to have 1 photon within the 6 arcmin off-peak 
	radius.
- Background is subtracted. 
- Have the final resolution of sigma=0.5 arcmin in all energy bands. 

For further details on the construction of the datasets, contact 
Maxim Markevitch <maxim@astro.isas.ac.jp>
---------------------------------------------------------------------------