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EINGALCAT - Catalog of Galaxies Observed by the Einstein Observatory IPC & HRI

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Overview

This is a catalog of galaxies observed in the X-ray band with the Einstein Observatory imaging instruments, the Imaging Proportional Counter (IPC) and the High Resolution Imager (HRI). The catalog comprises 716 observations of 493 galaxies, including those that were targets of pointed observations, and galaxies from the Revised Shapley-Ames (RSA) Catalog of Bright Galaxies and the Second Revised Catalog (RC2) Catalog of Bright Galaxies that were serendipitously included in Einstein fields, plus X-ray data on 4 other galaxies (LMC, SMC, M 31 = NGC 224, and M 32 = NGC 221) taken from the literature, for a total of 720 entries. A total of 450 of these galaxies were imaged well within the instrumental fields, resulting in 238 detections and 212 3-sigma upper limits. The other galaxies were either at the edge of the visible field of view or were confused with other X-ray sources.

Catalog Bibcode

1992ApJS...80..531F

References

An X-ray catalog and atlas of galaxies.
       Fabbiano G., Kim D.-W., Trinchieri G.
      <Astrophys. J. Suppl. Ser. 80, 531 (1992)>
      =1992ApJS...80..531F

Provenance

This database was created by the HEASARC in January 2002 based on CDS Catalog J/ApJS/80/531, tables gxatlas.dat and gxfluxes.dat.

Parameters

Name
The name of the galaxy, Object Designation (NGC, IC, UGC Number, LMC, or SMC).

RA
The Right Ascension of the galaxy, in the selected equinox. In the original ADC/CDS table, this information was given in B1950 equatorial coordinates and to a precision of 1 second of time. The 1950 equatorial coodinates were obtained from the RSA, RC2, or PGC (Principal Galaxies Catalog), notice, and thus are for the optical galaxy and not for the X-ray source.

Dec
The Declination of the galaxy, in the selected equinox. In the original ADC/CDS table, this information was given in B1950 equatorial coordinates and to a precision of 1 arcsecond. The 1950 equatorial coodinates were obtained from the RSA, RC2, or PGC (Principal Galaxies Catalog), notice, and thus are for the optical galaxy and not for the X-ray source.

LII
The Galactic Longitude of the galaxy.

BII
The Galactic Latitude of the galaxy.

NH
The line-of-sight equivalent Galactic column density of atomic hydogen H I in the direction of the galaxy in question, taken from Stark et al. (1992, ApJS, 79, 77), in units of atoms per square cm. This information is accurate to two significant digits.

Instrument
The Einstein Observatory instrument used for the observation, being either 'IPC' for the Imaging Proportional Counter or 'HRI' for the High Resolution Imager.

Sequence_Number
The Einstein Observatory Sequence Number for the observation, or 0 if the X-ray data were obtained from other sources.

Year
The year of the start of the observation.

Doy
The day of the year of the start of the observation.

Time
The date of the start of the observation in the standard HEASARC Browse format.

Live_Time
The live-time of the observation ("the time in the image"), in seconds, quoted to one decimal place.

Off_Axis
The angular offset of the optical center of the galaxy from the center of the instrument field, in arcminutes, and with a precision of 0.1 arcminutes.

Merge_Flag
This is a flag that is set to 'Y' for those galaxies for which the quoted X-ray data for a particular instrument are based on merged fields; in such cases, all of the entries for a given galaxy and instrument will have identical X-ray data tabulated.

Type_Flag
This is set to 'AGN' to identify galaxies for which the X-ray emission is likely to be dominated by an active nucles, or to 'VIR' to identify galaxies belonging to the Virgo Cluster.

Note_Flag
This is a flag that is set if there is a note on the source. The following values are used:

           `a' if the galaxy has an AGN
           `b' if it is a Virgo cluster member
           `c' X-ray data are from the following sources:
               LMC and SMC:  Long and van Speybroeck (1983) in "Accretion
                  Driven X-Ray Sources" Lewin and van den Heuvel eds.
                  (Cambridge:  Cambridge U. Press) p. 117.
               M 31 (NGC 224) and M 32 (NGC 221):
                  Trinchieri and Fabbiano (1991ApJ...382...82T)
               M 33 (NGC 598):  Trinchieri et al. (1988ApJ...325..531T)
               M 101 (NGC 5457):  Trinchieri et al. (1990ApJ...356..110T)
           `d' no morphological type available (peculiar galaxy)
           `e' combined flux of two sources (see table 8 of published paper)
  

Bmag
The B-band apparent magnitude obtaimed from the RSA, RC2 or PGC (Paturel et al., Principal Galaxies Catalog, CDS Cat. <VII/119>).

T_Type
The "T-type" of the galaxy, as defined in the RC2 (CDS Cat. <VII/112>), using morphological information taken from the RSA, RC2, or PGC.

RA1950_Xray
The Right Ascension (B1950) of the X-ray centroid for those galaxies detected by Einstein. If the parameter merge_flag is set to 'Y', the quoted X-ray data for a particular instrument are based on a merger of fields; in such a case, all of the entries for a given combination of galaxy and instrument will have identical tabulated X-ray data. This parameter was given to a precision of 1 second of time in the originating table.

Dec1950_Xray
The Declination (B1950) of the X-Ray centroid for those galaxies detected by Einstein. If the parameter merge_flag is set to 'Y', the quoted X-ray data for a particular instrument are based on a merger of fields; in such a case, all of the entries for a given combination of galaxy and instrument will have identical tabulated X-ray data. This parameter was given to a precision of 1 arcsecond in the originating table.

Extract_Radius
The radius used for the X-ray source counts extraction, in arcseconds.

Counts_Limit
A flag for the counts parameter that is set to "<" to indicate that it is a 3-sigma upper limit rather than a detection. In such cases, no value is given for the error is given for the counts_error parameter.

Counts
The total (background-subtracted) X-ray counts (or 3-sigma upper limit if counts_limit = "<") for the galaxy's X-ray emission. If the value of the merge_flag parameter is set to 'Y', then the quoted X-ray data for a particular instrument are based on a merger of fields; in such a case, all of the entries for a given combination of galaxy and instrument will have identical tabulated X-ray data.

Counts_Error
The 1-sigma error in the total (background-subtracted) X-ray counts for the galaxy's X-ray emission, for the X-ray detected galaxies.

Count_Rate_Limit
A flag for the count_rate parameter that is set to "<" in order to indicate that the quoted value is a 3-sigma upper limit rather than a detection.

Count_Rate
The count rate for the X-ray source (or 3-sigma upper limit if count_rate_limit = "<") associated with the galaxy and for the specified instrument, in ct/s. Notice that, if the parameter merge_flag is set to 'Y', then the quoted X-ray data for the particular instrument are based on a merger of fields; in such a case, all of the entries for a given combination of galaxy and instrument will have identical tabulated X-ray data.

Flux_Limit
A flag for the flux parameter that is set to "<" in order to indicate that the quoted value is a 3-sigma upper limit rather than a detection.

Flux
The 0.2-4.0 keV band flux for the X-ray source (or 3-sigma upper limit if flux_limit = "<") associated with the galaxy and for the specified instrument, in erg/cm^2/s. If the parameter merge_flag is set to 'Y', the quoted X-ray data for a particular instrument are based on a merger of fields; in such a case, all of the entries for a given combination of galaxy and instrument will have identical tabulated X-ray data.

Distance
The assumed distance to the galaxy, in megaparsecs (Mpc), derived assuming a Hubble constant of 50 km/s/Mpc, and corrected for the Virgocentric inflow.

Log_Lx_Limit
A flag for the log_lx (logarithm of the X-ray luminosity) parameter that is set to "<" in order to indicate that the quoted value corresponds to a 3-sigma upper limit rather than a detection.

Log_Lx
The logarithm of the derived X-ray luminosity (or 3-sigma upper limit if log_lx_limit = "<"), using the tabulated values of flux and distance, in units of ergs/s. If the parameter merge_flag is set to 'Y', the quoted X-ray data for a particular instrument are based on a merger of fields; in such a case, all of the entries for a given combination of galaxy and instrument will have identical tabulated X-ray data.


Contact Person

Questions regarding the EINGALCAT database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 15-Aug-2005