Improved Attitude Correction and Pileup Estimation for Suzaku Data
We present here two routines: aeattcor.sl and pile_estimate.sl, designed to aid in the analysis of Suzaku data. Both are scripts written in S-lang and are designed to be run on the command line using ISIS, the Interactive Spectral Analysis System, as a driver. Both utilize a number of S-Lang Modules Packages. For all intents and purposes, the scripts behave similar to typical Unix command line tools.
As documented by
"Restoring the Suzaku Source Position Accuracy and Point-Spread Function", Y. Uchiyama, Y. Maeda, M. Ebara, R. Fujimoto, Y. Ishisaki, M. Ishida, R. Iizuka, M. Ushio, H. Inoue, S. Okada, H. Mori, and M. Ozaki, 2008 PASJ, 60, p. 35thermal flexing of the Suzaku spacecraft leads to slow wobbling of the optical axis, and hence blurring of the image. Current Suzaku tools partially correct this effect by adjusting the spacecraft attitude file (based upon details of the spacecraft orbit, temperature, etc.). aeattcor.sl further improves this correction for bright sources by using their detected image to create a new attitude file. Applying this attitude file via the FTOOLS xiscoord command leads to sharper PSF images, as shown below. A more detailed description of aeattcor.sl is presented here.
Left: Standard Suzaku correction. Right: aeattcor.sl correction.
occurs in CCD detectors when two or more photons fall on the same
pixel during the same frame, and therefore are read as a single higher
energy photon or are discarded as a bad event.
pile_estimate.sl is designed to be run after
aeattcor.sl. It will create a smoothed,
discretized image for a given Suzaku chip. Rather than display count
rates, the image will show an estimated, minimum pileup fraction for
user specified levels. It then allows the user to create a region
file that excludes the most piled areas, and then estimates the
effective pileup fraction of the remaining events. An image is shown
below, and a more detailed description is presented
The estimated pileup fraction in a Suzaku image.
This page was last updated Apr 26, 2010 by Michael Nowak. To comment on it or the material presented here, send email to firstname.lastname@example.org.