Source Region Per-Stack Detections Exposure Map Files (regexp3.fits)
The source region stack exposure map consists of a single FITS format file for source regions of each stack of observations that results from catalog processing, for each science energy band. A full resolution instrument map for each observation in the stack that covers the detected source region rectangular bounding box is generated at the equivalent monochromatic energy for each energy band, and the exposure map is computed by applying the aspect histogram sampled at 0.5 arcsec resolution and blocking in SKY coordinates before combining into a stack of exposure maps. The blocking factor matches that used for the corresponding full-field image file. The rectangular SKY region filter is equal in size to the background region of interest (ROI) corresponding to the detected source region.
Stacked ACIS Region-of-Interest Exposure Map
![[Thumbnail image: stack of ACIS exposure maps for a region of interest]](imgs/acisfJ0035508m433654_r0083_stk_regexp.png)
[Version: full-size]
Stacked ACIS Region-of-Interest Exposure Map
Example of a stack of ACIS exposure maps for a given region-of-interest of two observations.
The stacked observations region exposure map FITS file is named: 〈i〉〈s〉〈stkpos〉_〈stkver〉N〈v〉_〈r〉〈b〉_regexp3.fits
where 〈i〉 is the instrument designation; 〈s〉 is the data source; 〈stkpos〉 is the position component of the stack name, formatted as "Jhhmmsss{p|m}ddmmss"; 〈stkver〉 is the 3-digit version component of the stack name, formatted with leading zeros; 〈v〉 is the data product version number; 〈r〉 is the region ID, formatted as "rnnnn", where nnnn is the 4-digit region number, formatted with leading zeros; and 〈b〉 is the energy band designation.