skip to main content

Title: An empirical method for improving the quality of RXTE PCA spectra

We fitted all of the several hundred RXTE PCA spectra of the Crab individually to a simple power-law model; the total number of counts in the composite spectrum is >10{sup 9}. We then used the spectrum of residuals to derive a calibration tool, called pcacorr, that we apply to large samples of spectra for GX 339-4, H1743-322, and XTE J1550-564. Application of the tool improved the quality of all the fits, and the improvement is dramatic for spectra with ≳ 10{sup 7} counts. The Crab residual spectrum is somewhat different for each of the five Proportional Counter Array (PCA) detectors, but it was relatively stable over the course of the mission. We recommend that pcacorr be routinely applied to spectra with ≳ 10{sup 6} counts and that one include a systematic error of 0.1%, rather than the 0.5-1% value that has customarily been used. We expect that application of the tool will result in an increase in sensitivity of the PCA to faint spectral features by up to an order of magnitude.
Authors:
; ;  [1] ; ;  [2]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. MIT Kavli Institute for Astrophysics and Space Research, MIT, 70 Vassar Street, Cambridge, MA 02139 (United States)
Publication Date:
OSTI Identifier:
22370471
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CALIBRATION; CRAB NEBULA; ERRORS; POLAR-CAP ABSORPTION; PROPORTIONAL COUNTERS; SENSITIVITY; SPACE VEHICLES; SPECTRA; X RADIATION