Source Region Per-Observation Detections Image Files (regimg3.fits, regimg3.jpg)
The source region image files consist of a set of FITS format image files, one for each source region of each observation, for each science energy band. Each source region image file is the image equivalent of the source region event file filtered by the appropriate science energy band and then ACIS observations are blocked by 1 and HRC observations are blocked by 2 in SKY coordinates. The resulting image is in flux units of photons s-1 cm-2 produced by subtracting the full-field background image in the appropriate science energy band from the filtered and blocked full-field event data and bound by the rectangular SKY region filter equivalent to the background region of interest (ROI) and further filtered by the corresponding stack-detected elliptical source region for the energy band, then dividing the result by the per-observation detections source region exposure map. A corresponding set of JPEG format image files are also produced for each source region equivalent to the source region FITS image file for each energy band.
ACIS Region Events Images
Combined per-observation source region images in FITS and JPEG format are named: 〈i〉〈s〉〈obs〉_〈obi〉N〈v〉[_〈c〉]_〈r〉〈b〉_reg.fits and 〈i〉〈s〉〈obs〉_〈obi〉N〈v〉[_〈c〉]_〈r〉〈b〉_reg.jpg
where 〈i〉 is the instrument designation, 〈s〉 is the data source; 〈obs〉 is the observation identification; 〈obi〉 is the observation interval identification; 〈v〉 is the data product version number; 〈c〉 is the cycle; 〈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. The optional discriminator identified in square brackets is included only for ACIS alternating exposure (interleaved) mode observations.