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EXGALEMOBJ: Help

EXGALEMOBJ - Hewitt & Burbidge (1991) Catalog of Extragalactic Emission-Line Objects


Overview

This is the Hewitt & Burbidge (1991) Optical Catalog of Extragalactic Emission-Line Objects Similar to Quasi-Stellar Objects. It contains a total of 935 galaxies which have optical properties similar to QSOs. Most of the objects appear to be nonstellar. The majority, more than 700, have redshifts z that are <= 0.2, and most have been classified as Seyfert galaxies, N systems, or radio galaxies. The redshift distribution peaks at z ~ 0.025, but there are about 200 powerful radio galaxies in the extended tail of the distribution which have z > 0.2. There is a separate and distinct peak in the redshift distribution at z = 0.06.

Notice that this catalog does not include star-like objects with emission-line redshifts >= 0.1 (these can be found in the HEASARC QSO database which contains the Revised and Updated Catalog of Quasi-Stellar Objects" of Hewitt, A. and Burbidge, G. 1993, ApJS, Vol. 87, pp. 451-947). Neither does it contain LINERs (sometimes called Seyfert 3 galaxies) or starburst galaxies.


Catalog Bibcode

1991ApJS...75..297H

References

"An Optical Catalog of Extragalactic Emission-Line Objects Similar to Quasi-Stellar Objects", Hewitt, A. and Burbidge, G. 1991, ApJS, Vol. 75, pp. 297-356.

Provenance

This database was created by the HEASARC in February 2001 based on CDS/ADC Catalog VII/178 (table1.dat).

Parameters

Name
The designation derived from the 1950 equatorial coordinates, using the prescription recommended by the Dictionary of Nomenclature of Celestial Objects. The original designation consisted of the RA and Dec (1950) truncated to 4 and 3 characters, respectively, and was not always unique. The Dictionary of Nomenclature of Celestial Objects recommended prefix used for objects in this catalog of 'HB91' (for Hewitt and Burbidge 1991) has been added by the HEASARC, e.g., 'HB91 0947+145'. In some cases where there are multiple objects with RA and Dec that are close enough that this designation is not unique, the Dictionary recommended adding suffixes of A, B, etc., presumably in order of increasing RA (1950), and this the HEASARC has also done, e.g., the object at RA and Dec (1950) = 00 39 09.80, +40 05 08.0 has been given the name of 'HB91 0039+400A', while that at RA and Dec (1950) = 00 39 32.34, 40 03 10.3 is named 'HB91 0039+400B'.

Alt_Name
The name by which the object is most commonly known. Sometimes only the catalog name is given, e.g., IRAS, if the full name is constructed from the RA and Dec in the standard way.

RA
The Right Ascension of the object. This was given in 1950 equinox and with varying precisions in the original published catalog.

Dec
The Declination of the object. This was given in 1950 equinox and with varying precisions in the original published catalog.

LII
The Galactic Longitude of the object.

BII
The Galactic Latitude of the object.

App_Mag
The apparent magnitude of the object. The authors have tried to use V magnitudes when they are available.

Redshift
The emission redshift z_em of the object.

Redshift_Flag
A flag that is set to ':' if the redshift is considered to be uncertain.

Ref_Redshift
A reference code for the emission redshift of the object. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/178/refs.dat

Alt_Name2
An alternative designation for the object.

Object_Type
An abbreviated expression for the object type, together with characterization of the optical emission-line spectrum, according to the following scheme:

     sy : Seyfert galaxy
     sy1: Seyfert 1
     sy2: Seyfert 2
     rg : Radio galaxy
     n  : Compact galaxy (see Morgan 1958, PASP, 70, 364; Matthews, Morgan, and
          Schmidt 1964, ApJ, 140, 35)
     e  : Emission lines present but not necessarily strong
     we : Weak emission lines
     me : Moderate emission Lines
     se : Strong emission lines
  
See Smith, Spinrad, and Smith (1976, PASP, 88, 621) for more information concerning the use of 'e', 'we', 'me', and 'se' to characterize the optical spectra of radio galaxies.

Ref_Object_Type
A reference code for the object type information. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/178/refs.dat

Alt_Name3
An alternative designation for the object.

Object_Type2
An alternative expression for the object type, using the same abbreviation scheme as for the object_type parameter (q.v.).

Ref_Object_Type2
A reference code for the alternative object type information. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/178/refs.dat

Alt_Name4
An alternative designation for the object.

Object_Type3
Another alternative expression for the object type, using the same abbreviation scheme as for the object_type parameter (q.v.).

Ref_Object_Type3
A reference code for the object_type3 parameter information. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/178/refs.dat

Alt_Name5
An alternative designation for the object.

Alt_Name6
An alternative designation for the object.

Alt_Name7
An alternative designation for the object.

Class
The HEASARC Browse object classification, based on the information given in the object_type parameter, or, failing that, the object_type2 or object_type3 parameters.


Contact Person

Questions regarding the EXGALEMOBJ 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
 
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