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ASCASIS - ASCA SIS Source Catalog

HEASARC
Archive

Overview

This preliminary ASCA SIS Source Catalog contains a list of point sources detected by the Solid-state Imaging Spectrometers (SIS) on-board the ASCA Observatory. This catalog was generated by searching for point-like sources in all data available from the HEASARC's ASCA PUBLIC archive (ASCAPUBLIC) as of 24 Oct 1996; and is populated by both target and serendipitous sources in the SIS field-of-view.

For each cataloged source various information is available, which includes the celestial coordinates of the source, the count rate, the significance of detection, and the hardness ratio, total aperture counts, exposure time, and start time of the observation. In addition, a set of three GIF "thumbnail" images is available in the broad (0.5 - 12 keV), soft (2 < keV), and hard (> 2 keV) spectral bands centered on the apparent detection. These images are convenient for accessing the quality of the source detection.

The current catalog is preliminary, the goal of the catalog authors being to make the SIS source list available as quickly as possible. To accomplish this, they took an incremental approach and placed their "work in progress" on-line, warts and all. They urge caution in using and citing these preliminary results, as they point out that the information is not, as yet, 100% reliable.


Catalog Bibcode

1997xisc.conf...31G

References

A full description of the ASCA archive and how to use it can be found under the WWW at http://heasarc.gsfc.nasa.gov/docs/asca/archive.html or in the ftp account at ftp://legacy.gsfc.nasa.gov/asca/doc/archive.txt

The current best reference for this catalog is: Gotthelf, E.V. and White, N.E. 1997, in `X-Ray Imaging and Spectroscopy of Cosmic Hot Plasmas', p. 31.


Provenance

This catalog was generated in January 1997 by Drs. Eric Gotthelf and Nicholas White and resulted from their search for point-like sources in all of the then-available SIS data files in the HEASARC's Public ASCA Data Archive as of 24 Oct 1996. The catalog is populated with both targetted and serendipitous sources that were present in the SIS field-of-view.

Data Products

Entries in the ASCASIS table have associated with them the standard ASCA public data products for the observation in which the source was detected (see http://heasarc.gsfc.nasa.gov/W3Browse/asca/ascamaster.html#dp_sets), as well as three GIF files containing the soft-band, hard-band, and broad-band images of the source that were specially constructed for this catalog.

Parameters

ObsID
A unique identifier for each ASCA observation set.

Name
The source designation within this catalog. The name is derived from the AXS prefix (for ASCA SIS X-ray source) and the apparent J2000 R.A. and Declination.

RA
The apparent Right Ascension of the source in the selected equinox.

Dec
The apparent Declination of the source in the selected equinox.

LII
The galactic longitude of the source.

BII
The galactic latitude of the source.

RA_1950
The apparent Right Ascension of the source in the B1950 equinox and in decimal degrees.

Dec_1950
The apparent Declination of the source in the B1950 equinox and in decimal degrees.

Count_Rate
The estimated total broad-band (0.5 to 12 keV) count rate at the telescope, in counts/second.

Count_Rate_Error
The error in the estimated total broad-band (0.5 to 12 keV) count rate at the telescope, in counts/second. (not currrently populated).

Sigma
The estimated significance of this source detection. Because of the complex ASCA mirror response function this number should be considered with caution.

HR
The estimated hardness ratio defined as the difference over the sum of the hard (2 - 12 keV) and soft (0.5 - 2 keV) band count rates at the source position (= [S-H] / [S+H]).

HR_Error
The estimated error on the hardness ratio (not currrently populated).

Counts
The accumulated total counts within in a 6 arcmin aperture centered on the source.

Exposure
The total "good" exposure time in seconds.

Start_Time
The start time of the observation.

File_GIF
The root filename for accessing the GIF image.


Contact Person

If you have questions regarding the ASCA SIS catalog, please contact Eric Gotthelf <evg@astro.columbia.edu> or Nick White <nwhite@lheapop.gsfc.nasa.gov> for science issues. If you have questions or problems related to the HEASARC database implementation, please contact the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 16-Feb-2005