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

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  VII/187 : the 1995 July version which was superseded by this catalogue
  VII/210 : the 1996 August version which was superseded by this catalogue
  VII/211 : the 1998 September version which was superseded by this catalogue
  VII/227 : the 2001 December version which was superseded by this catalogue
  VII/253 : the 2009 March version which was superseded by this catalogue
  VII/272 : the 2014 May version which was superseded by this catalogue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