Making Region Files (make-region)#

Pipeline module to generate DS9-compliant ICRS source and background regions.

This module can automate region creation, including contamination checking via XIMAGE. Thus, make-region is a good preliminary for making source and background regions. If user has DS9 installed, make-region will open DS9 so further adjustments can be made.

Positional arguments:

  • evtfile : Path to event FITS file.

  • ra, dec : Source coordinates in right ascension (RA) and declination in ICRS (decimal degrees).

  • r_in : Inner radius of source region in arcsec (default is 2” for Chandra, 45” for NuSTAR, and 25” for others).

  • r_out : Outer radius for background region in arcsec (default is 45” for Chandra, 125” for others).

  • outdir : Output directory (default: same as evtfile directory).

Options:
--ds9

Path to DS9 executable (if not available on which ds9).

--expimg

Path to exposure image file.

--help

Show help message

Output files:

  1. source.reg : circular region at the specified (RA, dec) with radius r_in in ICRS.

  2. bkg.reg : Annulus (if no contamination around source) with inner radius r_in and outer radius r_out or circular region with radius r_out in ICRS. make-region automatically relocates background if there is an XIMAGE detection to a cleaner spot within around 1’ from the source

  3. source_physical.reg : source region in physical coordinates (will only be generated if DS9 is executable)

  4. bkg_physical.reg : background region in physical coordinates (will only be generated if DS9 is executable)

Usage formula:
>>> make_region <evtfile> <ra> <dec> [r_in] [r_out] [outdir] [--ds9 DS9_PATH] [--expimg EXP_IMG]
Usage examples:
>>> make_region /path/to/event.fits 169.532 -32.456
>>> make_region /path/to/event.fits --expimg /path/to/exposure.img 169.532 -32.456
>>> make_region /path/to/event.fits --expimg /path/to/exposure.img 169.532 -32.456 25 150 ./output/
Optional requirements:

  • DS9 for more interactive region adjustments