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QSO: Help

QSO - Hewitt & Burbidge (1993) QSO Catalog


Overview

This is (a somewhat condensed form of) the Hewitt & Burbidge (1993) Revised and Updated Catalog of Quasi-Stellar Objects, and contains all then-known (to 1992 December 31) quasi-stellar objects (QSOs) with measured emission redshifts and BL Lac objects. The catalog contains 7315 objects, nearly all of which are quasi-stellar objects, and 89 of which are BL Lac objects. It contains extensive information on names, positions, magnitudes, colors, emission-line redshifts, absorption-line systems, etc.

The published version of this catalog (Hewitt & Burbidge 1993, ApJS, 87, 451) typically contained multiple rows on information for each object. This database basically has only the information given in the first row for every object, and is based on the CDS/ADC table VII/158 table1_1.dat.gz.


Catalog Bibcode

1993ApJS...87..451H

References

"A Revised and Updated Catalog of Quasi-Stellar Objects", Hewitt, A. and Burbidge, G. 1993, ApJS, Vol. 87, pp. 451-947.

Provenance

This database was created by the HEASARC in February 2001 based on CDS/ADC Catalog VII/158 (table1_1.dat.gz).

Description

The Hewitt & Burbidge "Revised and Updated Catalog of Quasi-Stellar Objects" is a standard QSO reference catalog. It includes as QSOs objects which are starlike (with or without `fuzz') and have z >= 0.1. A small number of objects discovered by Koo and Kron (1988, ApJ,325, 92) and Boyle (1986, Ph.D. thesis, Univ. of Durham) have been included which have redshifts in the range 0.3 to 0.65, but which those authors have described as blue compact galaxies because they have emission lines narrower than those in a ``typical'' QSO.

In the ealier versions of this catalog a few objects with z < 0.1 were included as QSOs since they had been called QSOs in the earlier literature. However, in order to make a clear division at z = 0.1, these objects have been removed from this current version of the catalog. Twenty-nine objects are in this category, 28 with z < 0.1 and one (0111-015) which has z = 0.120 since it is nonstellar.

The definition of a BL Lac object used for inclusion in this catalog is an object showing strong flux variations at all wavelengths which have been observed, a high degree of radio polarization, and an optical continuum containing no emission features. Such objects may also exhibit a high degree of optical polarization.

In addition to the parameters available in this database, the published catalog gives additional names, emission line species and wavelengths used to evaluate the emission redshift, redshifts, references and notes, etc. The structure of this information would not lead to efficient storage in a relational database, and consequently it has been excluded from this database. The full information can also be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/158/table1.dat.gz Additional information such as the numerical code for the references and an index of object names and coordinate designations can be found in the files refs.dat.gz, and table2.txt.gz and table2a.txt.gz, respectively, in the same directory as above.


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 'HB93' (for Hewitt and Burbidge 1993) has been added by the HEASARC, e.g., 'HB93 0000-026'. In some cases where there are multiple QSOs 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 QSO at RA and Dec (1950) = 00 02 26.7, -00 50 31. has been given the name of 'HB93 0002-008A', while that at RA and Dec (1950) = 00 02 45.9, -00 52 0.4 is named 'HB93 0002-008B'.

RA
The right ascension of the optical object. Most listed RA positions are taken from the identification paper or from the paper containing the redshift measurement. It should be noted that for QSOs close to bright galaxies, where no coordinates have been given in the literature, the galaxy coordinates have been used. When this has been done, the name of the galaxy (generally its NGC designation) appears as the name listed here rather than the name of the QSO.

Dec
The declination of the optical object. Most listed declinations are taken from the identification paper or from the paper containing the redshift measurement. It should be noted that for QSOs close to bright galaxies, where no coordinates have been given in the literature, the galaxy coordinates have been used. When this has been done, the name of the galaxy (generally its NGC designation) appears as the name listed here rather than the name of the QSO.

LII
The Galactic longitude of the object.

BII
The Galactic latitude of the object.

BLLac_Flag
A flag that is set to 'B' to indicate a BL Lac object.

Selected_Flag
A flag that specifies the selection technique(s) thus:

       C = UV-excess
       O = Objective-prism and related techniques
       R = radio
       V = variability
       X = X-ray
       S = serendipity
  
If the object was originally detected by one technique (e.g., radio) and it is subsequently detected as a source of radiation in another part of the spectrum, (e.g., X-ray), the codes will be listed sequentially, e.g., 'RX'.

Alt_Name
An alternative name for the object, in general the name under which the object was first identified. It should be noted that for QSOs close to bright galaxies, where no QSO coordinates have been given in the literature, the name of the galaxy (generally its NGC designation) appears as the alternate name listed here rather than the name of the QSO.

App_Mag
The apparent magnitude. Often the only apparent magnitude available is the photographic magnitude m_pg, the B magnitude, or an estimate from a Schmidt plate. Thus, these magnitudes are very uncertain and non-homogeneous.

Var_Flag
A flag that is set to 'V' if the optical object is known to be variable.

BV_Color
The B-V Color. For the majority of QSOs only rather crude measures of the energy distribution in the form of colors are available.

UB_Color
The U-B Color. For the majority of QSOs only rather crude measures of the energy distribution in the form of colors are available.

Redshift
The emission redshift, z_em. In general, the emission redshift is the best measured observational quantity for a QSO. Where a redshift has been reported, the full published catalog lists all the emission lines on which this redshift is based. In the current database, only the first of these emission lines is listed.

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

Abs_Redshift_Flag
A flag that is set to 'Y' if absorption redshift(s) are reported for the object.

Element
The ion on which the emission redshift is based. The full published catalog lists all of the ions and emission lines on which this redshift is based. In the current database, only the first listed ion and emission line is listed.

Wavelength_Element
The wavelength in Angstroms of the emission line (corresponding to the ion listed in the parameter "Element") on which the emission redshift is based.

Abs_Redshift
The largest (first listed) absorption redshift z_abs in the published version of the catalog. In the published catalog all absorption redshifts that the authors considered reliable were listed, except for the very large number of Lyman-Alpha/Lyman-Beta pairs which have been reported in a few high-redshift QSOs. In cases where the QSOs have broad absorption lines (BALs), mean absorption redshifts are difficult to measure, notice. Thus, very few z_abs values are given for BALs.

Ref_ID
A reference code for the identification of the QSO. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/158/refs.dat.gz

Ref_Redshift
A reference code for the emission redshift of the QSO. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/158/refs.dat.gz

LBQS_Flag
A flag that is set to 'B' to indicates that the QSO is in the Large Bright Quasar Survey (LBQS).

Ref_Var
A reference code for the variability of the QSO. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/158/refs.dat.gz

Ref_Radio
A reference code for the radio properties of the QSO. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/158/refs.dat.gz

Ref_Abs_Redshift
A reference code for the absorption redshift(s) of the QSO. The key to this code can be found in the CDS table: ftp://cdsarc.u-strasbg.fr/pub/cats/VII/158/refs.dat.gz

Notes
Notes and additional references. Abbreviations that are used include the following:

     absr   : 21cm absorption
     B(J)mag: defined in Koo & Kron 1982 (1982A&A...105..107K)
     BAL    : broad absorption line QSO
     BAL?   : broad absorption lines questionable
     BALvar : broad absorption lines variable
     Bmag   : B magnitude
     COem   : CO emission
     elp    : emission-line profile(s)
     emlvar : emission lines variable
     euv    : extreme ultra-violet spectra
     ext    : report of optical jet or fuzz
     fc     : finding chart
     FeIIem : many FeII lines
     hfe    : high-frequency excess
     hpq    : high polarization quasar
     imag   : imaging
     ir     : infrared
     ir/r   : infrared/radio
     IRAS   : object identified in IRAS catalog
     irpol  : infrared polarization
     irvar  : infrared variable
     Jmag   : defined in Koo & Kron 1982 (1982A&A...105..107K)
     m(or)  : passband on direct plates used in UK Schmidt Survey
     mf     : multifrequency observations
     mm     : millimeter-wave observations
     mmvar  : millimeter-wave variable
     neml   : narrow emission lines
     noabs  : no absorption (?)
     OVV    : optically violent variable
     phot   : photometry
     pol    : optical polarization
     poljet : polarized jet
     pos    : position
     QSO?   : doubtful QSO
     r/ir   : radio/infrared
     rjet   : radio jet
     rmag   : r magnitude
     rmap   : ?
     rnd    : not detected as radio source
     rpol   : radio polarization
     rvar   : radio variable
     si     : speckle interferometry
     sp     : spectra
     spext  : spectroscopy of the extension
     spvar  : spectral variability
     sy1    : Seyfert 1
     syi    : Seyfert (?)
     ubv    : colors
     ubvri  : extended photometry
     uv     : ultraviolet spectra
     uv/ir  : spectrophotometry in the ultraviolet and near infrared
     uvabs  : ultraviolet absorption
     uvem   : ultraviolet emission
     uvnd   : not detected in the ultraviolet
     uvvar  : ultraviolet variable
     var?   : possibly variable in the optical (?)
     varnd  : variability in the optical not detected (?)
     vlbi   : very long baseline interferometry
     x      : X-ray
     xnd    : not detected as X-ray source
     xvar   : X-ray variable
     zgal   : redshift of galaxy apparently containing BL Lac source
  

Class
The HEASARC Browse object classification: in this catalog, all objects have been the generic class of QSO except that those flagged as BL Lac objects (bllac_flag = 'B') have been classesd as BL Lacs.


Contact Person

Questions regarding the QSO 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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