ACDS V10.0 - Detailed Description of VII/274

ACDS V10.0 - Tue May 19 22:26:58 CEST 2026

| # Detailed Description of VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015) |

Note : this is the description file of the original catalog. This HTML page corresponds well to the original description, but some minor changes in the format may have been introduced in the FITS output files in order to allow for arithmetic operations on quantities such as coordinates and times. h:m:s and d:m:s units are normally converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the units; the value given in the HTML files supersedes the value indicated in the ReadMe file for this catalogue.

    VII/274             The Roma BZCAT - 5th edition                (Massaro+, 2015)
    ================================================================================
    The 5th edition of the Roma-BZCAT.
         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
    ================================================================================
    ADC_Keywords: QSOs ; BL Lac objects ; Galaxy catalogs ; Redshifts ; Photometry

    Keywords: BL Lacertae objects: general - galaxies: quasars: general - catalogs

    Abstract:
        The Roma-BZCAT is now at the 5th Edition which contains coordinates
        and multi-frequency data of 3561 sources, about 30% more than in the
        1st edition, 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
        and has a new format for the notes in the tables. We emphasize that
        all the sources in the Roma-BZCAT have a detection in the radio
        band. Moreover, a complete spectroscopic information is published
        and could be accessed by us for all of them, with the exception of BL
        Lac candidates. Consequently, peculiar sources as the so called
        "radio quiet BL Lacs", which are reported in some other
        catalogues, are not included here because of possible contamination
        with hot stars and other extragalactic objects.

    Description:
        In the 5th Edition we use similar denomination of
        blazars 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). We 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 the new
        adopted classification.

        The codes are defined in the "Note (G1)" below.

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

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × bzcat5.dat       133     3561   The Roma BZCAT - 5th edition

    See also:
     J/A+A/495/691 : Multifrequency catalogue of blazars, Roma-BZCAT (Massaro+ 2009)
     http://www.asdc.asi.it/bzcat : BZCAT Home Page

    Byte-by-byte Description of file:  bzcat5.dat

       Bytes Format Units   Label     Explanations

       1-  4  I4    ---     Seq       Sequential number
       6- 20  A15   ---     Name      Source name (based on J2000 position),
                                       5BZA JHHMM+DDMM (G1)
      22- 23  I2    h       RAh       Right ascension (J2000.0)
      25- 26  I2    min     RAm       Right ascension (J2000.0)
      28- 32  F5.2  s       RAs       Right ascension (J2000.0)
          34  A1    ---     DE-       Declination sign (J2000.0)
      35- 36  I2    deg     DEd       Declination (J2000.0)
      38- 39  I2    arcmin  DEm       Declination (J2000.0)
      41- 45  F5.2  arcsec  DEs       Declination (J2000.0)
      47- 52  F6.2  deg     GLON      Galactic longitude
      54- 59  F6.2  deg     GLAT      Galactic latitude
      61- 65  F5.3  ---     z         Redshift
          66  A1    ---     u_z       [?] uncertainty flag on z
      68- 71  F4.1  mag     Rmag      ?=0 R magnitude
      73- 96  A24   ---     Class     Source classification
      98-105  F8.1  mJy     FR        ?=0 Flux density at 1.4/0.843GHz
     107-111  I5    mJy     F143      ?=0 Flux density at 143GHz
     113-118  F6.2  fW/m2   FX        ?=0 X-ray flux 0.1-2.4keV
     120-126  E7.3  cm2/s   FF        ?=0 Fermi flux1-100GeV (in ph/cm2/s)
     128-133  F6.3  ---     aro       Spectral index radio-optical

    Global Notes:

    Note (G1): The classifications are:
        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;
        BZU  = 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.

    History:
        Copied at http://www.asdc.asi.it/bzcat
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    (End)                                      Patricia Vannier [CDS]    11-Feb-2016