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ROMABZCAT - Roma-BZCAT Multi-Frequency Catalog of Blazars

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Overview

This table contains the 5th edition of the Roma-BZCAT catalog of blazars which contains coordinates and multi-frequency data of 3561 sources. It presents several relevant changes with respect to the past editions which are briefly described in the reference paper.

The Roma-BZCAT catalog contains data on 3561 sources, about 30% more than in the 1st edition, which either confirmed blazars or exhibiting characteristics close to this type of sources. With respect to the previous editions, this new edition has relevant changes in the sources' classification. The authors emphasize that all the sources in the Roma-BZCAT have a detection in the radio band. Moreover, complete spectroscopic information is published and could be accessed by the authors for all of them, with the exception of BL Lac candidates. Consequently, peculiar sources such as the so called "radio quiet BL Lacs", which are reported in some other catalogs, are not included here because of possible contamination by hot stars and other extragalactic objects.

In the 5th edition, the authors use a similar denomination for the blazars to that adopted in the previous editions. Each blazar is identified by a code, with 5BZ for all blazars, a fourth letter that specifies the type (B, G, Q or U), followed by the truncated equatorial coordinates (J2000). The authors introduced the edition number before the letters BZ to avoid possible confusion due to the fact that several sources changed their old names because of a newly adopted classification.

The 5th edition contains 1151 BZB sources (92 of which are reported as candidates because their optical spectra could not be found in the literature), 1909 BZQ sources, 274 BZG sources, and 227 BZU objects.


Catalog Bibcode

2015Ap&SS.357...75M

References

The 5th edition of the Roma-BZCAT. A Short Presentation
     Massaro E., Maselli, A., Leto C., Marchegiani P., Perri M., Giommi, P.,
     Piranomonte S.
     <Astrophys. Space Sci., 357, 75 (2015)>
     =2015Ap&SS.357...75M
     =2016yCat.7274....0M

Provenance

This database table was originally ingested by the HEASARC in September 2013, based on CDS Catalog J/A+A/495/691 file bzcat4.dat. It was updated in March 2016, and it is now based on CDS Catalog VII/274 file bzcat5.dat.

Parameters

Source_Number
A uniquely identifying source number for each blazar in the catalog in order of increasing J2000.0 Right Ascension.

Name
The Roma-BZCAT source designation, e.g., '[MML2015] 5BZx JHHMM+DDMM' where the first part stands for Massaro, Maselli, Leto et al. 2015, 5th edition of the Roma-BZCAT (and has been added by the HEASARC in accordance with a recommendation by the CDS Dictionary of Nomenclature of Celestial Objects), the character 'x' can be 'B', 'G', 'Q', or 'U', depending on the blazar sub-type:

      5BZB = BL Lac objects, used for AGNs with a featureless optical
        spectrum, or having only absorption lines of galaxian origin and weak
        and narrow emission lines;
      5BZG = sources, usually reported as BL Lac objects in the literature,
        but having a spectral energy distribution (SED) with a significant
        dominance of the galaxian emission over the nuclear one
      5BZQ = Flat Spectrum Radio Quasars, with an optical spectrum showing
        broad emission lines and dominant blazar characteristics;
      5BZU = blazars of uncertain type, adopted for a small number of sources
        having peculiar characteristics but also exhibiting blazar activity:
        for instance, occasional presence/absence of broad spectral lines or
        other features, transition objects between a radio galaxy and a BL
        Lac, galaxies hosting a low luminosity blazar nucleus, etc.
  
and the 'HHMM+DDMM' part corresponds to the (truncated) J2000.0 equatorial coordinates of the blazar.

RA
The Right Ascension of the blazar in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 or 0.1 seconds of time in the original table. The coordinates are mostly derived from VLBI (Titov and Malkin (2009, A&A, 506, 1477); Titov et al. (2011, A&A, 529, A91); Petrov and Taylor (2011, AJ, 142, 89), WISE and optical databases like SDSS.

Dec
The Declination of the blazar in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 or 0.1 arcseconds in the original table. The coordinates are mostly derived from VLBI (Titov and Malkin (2009, A&A, 506, 1477); Titov et al. (2011, A&A, 529, A91); Petrov and Taylor (2011, AJ, 142, 89), WISE and optical databases like SDSS.

LII
The Galactic Longitude of the blazar.

BII
The Galactic Latitude of the blazar.

Redshift
The redshift of the blazar.

Redshift_Flag
A flag parameter for the redshift indicating uncertainty in the value ('?').

Rmag
The R-band magnitude of the blazar taken from the USNO-B1 Catalog, the r-band magnitude from SDSS DR10, or the magnitude in other bandpasses when these data are not available.

Object_Type
The blazar sub-type classification.

Flux_1p4_GHz
The radio flux density of the blazar at 1.4GHz (from NVSS or FIRST), in mJy. Alternatively, if the 1.4-GHz flux density is not known, the flux density at 0.843 GHz from SUMSS is given instead.

Flux_143_GHz
The microwave flux density of the blazar, mostly at 143 GHz from the Planck Compact Source Catalogue Public Release 1, in mJy.

Xray_Flux
The X-ray flux of the blazar in the 0.1-2.4 keV band, taken from the ROSAT Archive or from Swift-XRT catalogs, or in a few cases from other sources, in erg cm-2 s-1.

GR_Photon_Flux
The gamma-ray flux of the blazar in the 1-100 GeV band, taken from Fermi, in photons cm-2 s-1.

RO_Spectral_Index
The radio-to-optical spectral index of the blazar.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 3-Mar-2016