HEASARC
Archive

XCOLL - X-Ray Collimators Catalogs

HEASARC
Archive

Overview

The XCOLL database table has been deprecated. Please query the individual component catalogs (listed below) separately instead.

XCOLL was a master catalog which contained selected parameters from HEASARC X-ray catalogs containing the results of surveys made with collimated detectors. In general these sources have error boxes that are relatively large and irregularly shaped. XCOLL was created by copying all of the entries and common parameters from the following catalogs:

 * A1 - HEAO 1 A-1 X-Ray Source Catalog

 * A2LED - HEAO 1 A-2 LED Catalog

 * ARIEL3A - 3A (Third Ariel-V) Catalog

 * UHURU4 - 4th UHURU X-ray Catalog (Forman et al. 1978)
The XCOLL database table had many entries but relatively few parameters; it provides users with a general overview of X-ray sources detected with collimated detectors. Each entry in XCOLL has a parameter called 'database_table' which indicates from which original catalog database the entry was copied; users should "browse" that original catalog should they wish to examine ALL of the parameter fields for a particular entry.

Also, to obtain more detailed information about original catalog, or about the instrument used in the experiment, users should access the online help for that catalog.

For some entries in XCOLL, certain of the parameter fields are blank (or have zero values); this indicates that the original database did not contain that particular parameter. (For example, the 'flux_mCrab' parameter is often blank for this reason.)


Parameters

Name
The commonly-used name of the sources.

RA
The Right Ascension of the X-ray source, in degrees.

Dec
The Declination of the X-ray source, in degrees.

LII
The galactic longitude of the X-ray source.

BII
The galactic latitude of the X-ray source.

RA1
Right Ascension of the first corner of the error box surrounding the source.

RA2
Right Ascension of the second corner of the error box surrounding the source.

RA3
Right Ascension of the third corner of the error box surrounding the source.

RA4
Right Ascension of the fourth corner of the error box surrounding the source.

Dec1
Declination of the first corner of the error box surrounding the source.

Dec2
Declination of the second corner of the error box surrounding the source.

Dec3
Declination of the third corner of the error box surrounding the source.

Dec4
Declination of the fourth corner of the error box surrounding the source.

Catalog_Designation
The catalog designation is the name of the source as assigned in the particular catalog from which it comes.

Count_Rate
The count rate associated with the source (counts per second). The associated error parameter is 'count_rate_error'.

Count_Rate_Error
The error in count rate.

Database_Table
Database table this entry comes from

Detection_Significance
The probability that this source is a result of background fluctuation.

Error_Radius
The position error radius. (Note: All values are zero as populated.)

Exposure_Time
The exposure time for the observation, in seconds.

Filter
The name of the filter used for the observation, if any.

Flux
The flux in erg s-1 cm-2, usually obtained by multiplying the given count rate by a conversion factor. The 'flux_error' parameter contains the associated error, in the same units.

Flux_Error
The uncertainty in the flux, in erg s-1 cm-2.

Flux_mCrab
The flux in milliCrab.

Flux_mCrab_Error
This parameter contains the error associated with 'flux_mCrab', also in milliCrab.

Sequence_Number
The observation sequence number for the source, if present.

Serial_Number
This is a running serial number used within some of the catalogs to indicate source order.

Source_Size
The size of the source if it is extended, in arc seconds.


Contact Person

Questions regarding the XCOLL database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Thursday, 24-May-2012 11:22:22 EDT