TG_FINDZO: Finding the Zeroth Order Centroid
TG_FINDZO: An algorithm for finding zeroth order positionTG_FINDZO is an algorithm for detecting a centroid position of a zeroth order image of Chandra HETGS and LETGS by finding an intersection between grating arms and a data transfer streak.
The new routine is designed to handle the following cases:
It is often ideal to use this algorithm for detecting the position of a extremely bright source (e.g., X-ray binaries) in the HETGS (or LETGS) + ACIS-S configuration. When the source is faint and/or the HRC-S is used as a detector (hence the pile-up is not an issue), tgdetect is recommended for the zeroth order detection.
For more information, see this detailed description of the tg_findzo algorithm.
This page was last updated Sep 20, 2011 by David P. Huenemoerder. To comment on it or the material presented here, send email to firstname.lastname@example.org.