LEDAS  
Leicester Database and Archive Service
 
ARNIE Index
ARNIE Help
ARNIE Tutorial
Search...
All databases
All helpfiles
Line
Footer
E-mail

HRIDEEP: Help

HRIDEEP - Einstein Catalog HRI Deep Survey


Overview

This database table contains primary HRI source parameters for the 202 HRI sources found in the Einstein Deep Survey. The Einstein Deep Survey (EDS) program consisted of very deep X-ray exposures in selected regions of the sky at high galactic latitude. The main purposes of the survey are to investigate the nature of the extragalactic X-ray background through direct source counts at very low flux levels and to study the nature of the very faint X-ray sources which comprise a significant fraction, if not all, of the soft X-ray background.

Catalog Bibcode

1991ApJ...374..440P

References

Primini, F.A., Murray, S.S., Huchra, J., Schild, R., Burg, R., and Giacconi, R. Imaging X-ray Astronomy, ed. M. Elvis (Cambridge, Cambridge University Press), p. 337.

Primini, F.A., Murray, S.S., Huchra, J., Schild, R., Burg, R., and Giacconi, R. 1991, Ap.J., 374, 440.


Parameters

Background_Counts
The expected background value in the standard circle determined from the background in a 5' region about the target center, scaled by the circle size and the exposure at the source location.

BII
The Galactic Longitude of the object.

Cell_Size
The size of the detection cell, in arcseconds, in which the source was detected.

Count_Rate
The count rate for each HRI source detected, in counts per second. The count rates have been corrected for vignetting, scattering, dead time, and detector efficiency.

Count_Rate_Error
The count rate error for each HRI source detected. The count rates have been corrected for vignetting, scattering, dead time, and detector efficiency.

Dead_Time
The dead time correction factor at the time of the observation.

Dec
The Declination of the object.

Detect_Counts
The number of counts in a detect cell centered at the best position for each HRI source.

E_Circle_Counts
The number of counts in a circle of equivalent area is given.

Exposure
The total exposure time, in seconds, at the source position. The exposure time is corrected for intervals lost due to unacceptable aspect solution, detector dead time, and other event screening. It may differ from the net time in the processed image if the source is not in the field of view for the entire observation.

Ext_Background_Counts
The background in the extended circle.

Ext_Circle_Counts
The number of counts in an extended circle (that circle which circumscribes all detect cells above threshold).

Ext_Circle_Radius
The radius of the extended circle in arcseconds.

Ext_Scatter_Counts
The fraction of source counts scattered out of the extended circle.

LII
The Galactic Latitude of the object.

Name
The source designation derived from position.

Pos_Error
The positional uncertainty, in arcseconds.

Quantum_Efficiency
The detector quantum efficiency at the source position.

RA
The Right Ascension of the object.

S_Circle_Counts
The source counts in the 18" circle.

Scatter_Counts
The fraction of total source counts scattered out of the standard 18" circle.

Sequence_Num
The Einstein Observatory sequence number, a two to five digit number which uniquely identifies the observation. The numbers were assigned sequentially at the time of proposal submission.

Source_Correct
The size correction factor, which adjusts intensities for extended sources. Source Correct is conceptually similar to the classical beam broadening correction used by radio astronomers when performing drift scans with single-dish telescopes. This serves to correct all intensity measurements (optimized for point sources) of resolved sources for the X-ray brightness which is outside of the detection box. It can be used with any intensity measurement (counts, count rate, or flux) to obtain an estimate for extended sources. For more information, please consult the HEASARC.

Source_Num
The HRI source number within the field of observation.

Vignetting_Correct
The telescope vignetting correction at the source position.

Y_Position
The location of the source, in pixels.

Z_Position
The location of the source, in pixels.


Contact Person

Questions regarding the HRIDEEP database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
HOME
SEARCH
SERVICES INFO SOFTWARE ViZieR BLASTA DSS
ARCHIVES ASCA CHANDRA GINGA ROSAT ARNIE