HEXTE calibration and data analysis news
Disclaimer:
Items presented here represent our latest knowledge of the HEXTE instrument
and data analysis, but may change rapidly and so should be used with
caution.
The "official" calibration products and information for the HEXTE are
provided by the RXTE Guest Observer
Facility.
A HEXTE Calibration paper is in preparation, and will contain sections
on:
- Dead-time
- Collimator response and geometric area - WWW link coming soon.
- Response matrix
- Background
- Timing
- Spectroscopy
For an overview of the HEXTE, please refer to the in-flight performance
paper by Rothschild et al. (1998): Astrophysical Journal
496, 538.
News: 1998 October 20
The PCA and HEXTE teams are working together on cross-calibration, using a
common set of public observations of the Crab Nebula, taken 1997 December.
See the new RXTE
Cross-calibration WWW page for details.
The HEXTE team are preparing new calibration products: collimator responses
and effective area files (ARFs) for release in the near future. These
products are the result of fits to Crab scans with a model for the spreading
of the collimator tubes.
The response matrix files (RMFs) are currently unchanged since the release
of 1997 March 20.
Watch this space for the new calibration products and Crab spectra,
which can be used as templates for comparison with other HEXTE
observations.
HEXTE calibration work in progress:
- Testing the HEXTE dead time model using data from the 241Am
calibration source - so far, the results validate the model currently used
by
hxtdead. See the HEXTE
Dead-time WWW page for further details.
- Verifying the collimator responses by fitting scans across other
sources - results of Crab scans to be appearing on a WWW page soon.
- Measuring the detector open areas using ground calibration data
- Understanding the origins of the residuals observed when fitting
bright-source spectra, to improve the response matrix (RMF)
- Installation of all HEXTE calibration files in the CALDB for
ease-of-use - under testing by the RXTE GOF.
Currently available:
1998 October 20:
HEXTE Crab reference spectra and latest response files are available
from the HEXTE ftp area. See the README file for details. Please contact
Philip Blanco if you intend to use these data in your research.
1997 March 20:
The latest HEXTE response matrices are available as a gzip tar file.
(These are numerically identical to the previous release, 1997 March 3, but
can now be used with RBNRMF and MARFRMF).
For a description, see the included README.
Absorption model description
of the materials in front of the HEXTE detectors' apertures.
High Energy X-ray Timing Experiment
Send questions or comments to Philip Blanco
pblanco@ucsd.edu