ARF Correction Script
contamarf is an ISIS script which reads an existing ARF, reads the contamination FITS file, evaluates the contamination function on the ARF's grid at the ARF's time, scales the response by the factor, and writes a new ARF. Options allow explicit specification of the contamination data file and the time.
contamarf is run from the unix prompt and invokes isis-script. Hence, isis must be in your path. contamarf also assumes the default contamination file is in your current directory, with the default name, acisD1999-08-13contamN0001.fits.
Future releases of CIAO will automatically incorporate the contamination data into responses via ardlib and the CALDB through the usual response tools (mkarf, mkgarf, mkinstmap).
Note: Your input ARF should have been made with the "N0003" ACIS QE. "N0004", which was released for use with LETG/ACIS-S, includes some contamination. The QE file used is recorded in the file header. E.g.,
-- HISTORY ARDLIB History Records -- HISTORY -------------------------------- -- HISTORY ARDLIB Version: 0.6.3-3 -- HISTORY ACIS QE File: /nfs/cxc/a1/i686/opt/CIAO_2.2_linux/CALDB/data/chandra/aci -- HISTORY s/bcf/qe/acisD1997-04-17qeN0003.fits[AXAF_QE8]
MEG ARF (red) and corrected version output by contamarf (green)
unix> ./contamarf Usage: contamarf arf_in arf_out [tstart [contam_file]] Default TSTART read from arf_in. Default contam_file=./acisD1999-08-13contamN0001.fits Apply the contamination function to the input ARF file. Write the result to a new ARF. TSTART is in seconds since MJDREF=1998.00 Example: Compute the TSTART for a time in early 2003: isis> () = printf("%20.0f\n",(2003.0+1/12.-1998.0)*86400*365.25); 160417800 unix> contamarf arf.fits arf_new.fits 160417800
See isis for download and installation instructions.
This page was last updated Feb 7, 2003 by David P. Huenemoerder. To comment on it or the material presented here, send email to firstname.lastname@example.org.