ACDS V10.0 - Detailed Description of VII/278

ACDS V10.0 - Sun Jan 19 16:23:58 CET 2025

| # Detailed Description of VII/278 : A Catalogue of Galactic Supernova Remnants (Green 2017) |

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/278         A Catalogue of Galactic Supernova Remnants          (Green 2017)
    ================================================================================
    A Catalogue of Galactic Supernova Remnants, 2017 June version.
       Green D.A.
      <Cavendish Laboratory, Cambridge, United Kingdom (2017)>
      =2017yCat.7278....0G
    ================================================================================
    ADC_Keywords: Supernova remnants ; Milky Way ; Nonstellar objects

    Description:
        This catalogue of known Galactic supernova remnants (SNRs) is an
        updated version of the catalogues of Galactic SNRs presented in detail
        in Green (1984, 1988), in summary form in Green (1991, 1996, 2004,
        2009, 2014), and on the Web (versions of 1995 July, 1996 August, 1998
        September, 2000 August, 2001 December, 2004 January and 2006 April).
        (Note that version published in Green (1996) was produced in 1993.)

        This the 2017 June version of the catalogue contains 295 SNRs, and is
        based on results published in the literature up to the end of 2016.
        The basic summary data included in this catalogue for each SNR are its
        Galactic coordinates, RA and Dec (J2000.0), angular size, type, flux
        density at 1 GHz, spectral index, and any other names. Notes on these
        parameters, on possible remnants not included, and questionable SNRs
        listed in the catalogue are given in the full version of the catalogue
        on the Web. It should be noted that there are selection effects which
        apply to the identification of Galactic SNRs (e.g., Green 1991, 2004,
        2005, 2009), so that care should be taken if these data are used in
        any statistical studies.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × snrs.dat          88      295   Supernova Remnant catalogue

    See also:
      VII/187 : the 1995 July version which was superseded by this catalogue
      VII/210 : the 1996 August version which was superseded by this catalogue
      VII/211 : the 1998 September version which was superseded by this catalogue
      VII/227 : the 2001 December version which was superseded by this catalogue
      VII/253 : the 2009 March version which was superseded by this catalogue
      VII/272 : the 2014 May version which was superseded by this catalogue

      http://www.mrao.cam.ac.uk/surveys/snrs/ : the detailed on-line version

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

       Bytes Format Units   Label     Explanations

       1- 11  A11   ---     SNR      *Supernova Remnant designation
      14- 15  I2    h       RAh      *Right Ascension J2000 hours
      17- 18  I2    min     RAm      *Right Ascension J2000 minutes
      20- 21  I2    s       RAs      *Right Ascension J2000 seconds
          24  A1    ---     DE-      *Declination sign
      25- 26  I2    deg     DEd      *Declination J2000 degrees
      28- 29  I2    arcmin  DEm      *Declination J2000 arcminutes
      31- 35  F5.1  arcmin  MajDiam  *Major Angular Size of remnant
          36  A1    ---     ---       [x]
      37- 41  F5.1  arcmin  MinDiam  *? Minor Angular Size of remnant
          42  A1    ---    u_MinDiam  [?] Uncertainty flag on Angular Size
      44- 45  A2    ---     type     *[CFS? ] Type of remnant
          47  A1    ---    l_S(1GHz)  [>] Limit flag on S(1GHz)
      48- 53  F6.1  Jy      S(1GHz)  *? Flux Density at 1 GHz
          54  A1    ---    u_S(1GHz)  [?] Uncertainty flag on S(1GHz)
      56- 59  F4.2  ---     Sp-Index *? Spectral Index of integrated radio emission
      60- 61  A2    ---   u_Sp-Index *[?v ] Uncertainty and variability flag on SI
      63- 88  A26   ---     Names    *Other names commonly used

    Note on SNR:
      This designation is based on the galactic longitude and latitude of
      the source centroid quoted to the nearest tenth of a degree.
    Note on RAh, RAm, RAs, DE-, DEd, DEm:
      The accuracy of the quoted values depends on the size of the
      remnant. For small remnants they are to the nearest few seconds of
      time and the nearest minute of arc for RA and DEC respectively. For
      the larger remnants they are rounded to coarser values. They are in
      every case sufficient to specify a point within the boundary of the
      remnant. These coordinates are generally deduced from radio maps
      rather than from X-ray or optical observations, and are J2000.0.
    Note on MajDiam, MinDiam:
      Usually taken from the highest resolution radio map available. The
      boundary of most remnants approximates reasonably well to a circle or
      an ellipse; a single value is quoted for the angular size of the more
      nearly circular remnants, which is the diameter of a circle with an area
      equal to that of the remnant, but for elongated remnants the product of
      two values is quoted, and these are the major and minor axes of the
      remnant boundary modeled as an ellipse. In a few cases an ellipse is not
      a satisfactory description of the boundary of the object (refer to the
      description of the individual object given the detailed catalogue entry
      on the Web), although an angular size is still quoted for information.
      For 'filled-centre' remnants the size quoted is for the largest extent
      of the observed radio emission, not, as at times has been used, the
      half-width of the centrally brightened peak.
    Note on S(1GHz):
      The flux density of the remnant at 1GHz in jansky. This is not a
      measured value, but that deduced from the observed radio frequency
      spectrum of the source. The frequency of 1 GHz is chosen because flux
      density measurements at frequencies both above and below this value
      are usually available. Note that some young remnants -- notably
      G111.7-2.1 (=Cassiopeia A) and G184.6-5.8 (=Crab Nebula) -- show
      secular variations in their radio flux.
    Note on Sp-Index, u_Sp-Index:
      The spectral index is of the integrated radio emission from the
      remnant, {alpha} where S({nu}) {prop.to} {nu}-{alpha}. This
      is either a value quoted from the literature, or one deduced from the
      available integrated flux densities of the remnant. For several SNRs a
      simple spectral model is not adequate to describe their radio emission
      because the spectral index varies across the face of the remnant or
      that the integrated spectrum is curved, and in these cases the spectral
      index includes the 'v' in u_SI. In some cases, for example where the
      remnant is highly confused with thermal emission, the spectral index
      is given as '?' since no value can be deduced with any confidence.
    Note on type:
      S = remnant shows a shell radio structure
      F = remnant shows a filled center ('plerion') radio structure
      C = remnant shows a composite (or combination) radio structure
      S?, C?, F? = if there is some uncertainty
      ? = object is conventionally considered a SNR although its nature is
         poorly known or not well understood.
    Note on Names:
      Other names commonly used for the object. These are given in
      parentheses if the remnant is only part of the source. For some
      objects, notably the Crab Nebula, not all other names are given.

    Remarks:
      The on-line version on the World-Wide-Web at

         http://www.mrao.cam.ac.uk/surveys/snrs/

      contains much more information on the individual objects,
      including many references, plus discussion of possible and
      probable remnants that have been reported in the literature
      but which are not included in the catalogue.

    History:
        * 30-Jun-2017: Prepared by Dave Green,

    References:
     Green, D.A., 1984, MNRAS, 209, 449        =1984MNRAS.209..449G
     Green, D.A., 1988, Ap&SS, 148, 3          =1988Ap&SS.148....3G
     Green, D.A., 1991, PASP, 103, 209         =1991PASP..103..209G
     Green, D.A., 1996, in Supernovae and Supernova Remnants, (the
       proceedings IAU Colloquium 145), eds McCray R. & Wang Z.,
       (Cambridge University Press), p419.     =1996ssr..conf..419G
     Green, D.A., 2004, BASI, 32, 335          =2004BASI...32..335G
     Green, D.A., 2005, MmSAI, 76, 534         =2005MmSAI..76..534G
     Green, D.A., 2009, BASI, 37, 45           =2009BASI...37...45G
     Green, D.A., 2014, BASI, 42, 47           =2014BASI...42...47G
    ================================================================================
    (End)   Dave Green [Cavendish Laboratory], Patricia Vannier [CDS]    30-Jun-2017