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Computer-readable version of General Catalogue of Variable Stars,
Vol.V. Extragalactic Variable Stars.



III. STRUCTURE OF THE CATALOGUE OF EXTRAGALACTIC SUPERNOVAE
(Files : sn_cat, sn_rem, sn_ref)
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File Summary:
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FileName Lrecl Records Explanations
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sn.txt 80 158 Extragalactic supernovae. Description
sn_cat.dat 123 984 Extragalactic supernovae. Catalogue
sn_rem.dat 80 278 Extragalactic supernovae. Remarks
sn_ref.dat 158 674 Extragalactic supernovae. References
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The total number of objects in the Catalogue of extragalactic supernovae is
984.

We have compiled the Catalogue of extragalactic supernovae using the
GCVS card catalogue. We paid attention mainly to positional and
photometric information on stars themselves. The catalogue includes
supernovae that appeared before the end of 1993. To improve information
on parent galaxies, we used in some cases a computer version of the
Third Reference Catalogue of Bright Galaxies by G. de Vaucouleurs, A. de
Vaucouleurs, H.G. Corwin, Jr., R.J. Buta, G. Paturel, P. Fouque, 1991,
New York: Springer and the NASA/IPAC Extragalactic Database (NED) which
is operated by the Jet Propulsion Laboratory, Caltech, under contract
with the National Aeronautics and Space Administration. The catalogue
is arranged in chronological order of the SN designations.

Table 3.
Byte-per-byte description of file sn_cat.dat:
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Bytes Format Units Label Explanations
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1- 6 A6 --- SN Supernova designation
7 A1 --- n_SN [-?] Doubtful (?), or rejected (-) SN
8 A1 --- RemFlag [*] The '*' indicates a remark in sn_rem.dat
10- 19 A10 --- Gal Parent galaxy designation
21- 22 I2 h RAh Right Ascension 1950 of Parent galaxy
23- 24 I2 min RAm Right Ascension 1950 (minutes)
25- 28 F4.1 s RAs Right Ascension 1950 (seconds)
29 A1 --- DE- Declination 1950 (sign)
30- 31 I2 deg DEd Declination 1950 of Parent galaxy
32- 33 I2 arcmin DEm Declination 1950 (minutes)
34- 35 I2 arcsec DEs Declination 1950 (seconds)
36 A1 --- u_DEs [":'] Accuracy flags
37- 42 A6 --- MType Type of the parent galaxy
43- 47 F5.2 mag BT Integrated magnitude of parent galaxy
48 A1 --- u_BT Uncertainty flag (:) on BT
49 A1 --- n_BT [BJV] Band indicator, blank for photographic
51- 58 A8 --- maxDate Date of the SN's maximum or of discovery
60- 64 F5.2 mag magMax Magnitude at maximum (light) of SN
65 A1 --- u_magMax Uncertainty flag (:) on magMax
66 A1 --- n_magMax [BJVRIKr] Band indicator, blank for
photographic
67 A1 --- f_magMax [*] '*' if maximum not observed
69- 71 I3 arcsec dRA Distance of SN from galaxy nucleus
72- 73 A2 arcsec oRA [NSEW:? ] Orientation of dRA
74- 76 I3 arcsec dDE Distance of SN from galaxy nucleus
77- 78 A2 arcsec oDE [NSEW:? ] Orientation of dDE
79- 80 I2 h RAhSN Right Ascension 1950 of SN
81- 82 I2 min RAmSN Right Ascension 1950 (minutes)
83- 86 F4.1 s RAsSN Right Ascension 1950 (seconds)
87 A1 --- DE-SN Declination 1950 (sign)
88- 89 I2 deg DEdSN Declination 1950 of SN
90- 91 I2 arcmin DEmSN Declination 1950 (minutes)
92- 93 I2 arcsec DEsSN Declination 1950 (seconds)
94 A1 --- u_DEsSN [":'] accuracy flags on SN position
95-100 A6 --- SNType SN classification
102-117 A16 --- Discov Name of the SN discoverer
118-120 A3 --- snRef1 Reference for study of the star,
see file sn_ref.dat
121-123 A3 --- snRef2 Reference for chart or photograph,
see file sn_ref.dat
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THE SUPERNOVA'S DESIGNATION followed by a question mark (?) refers to
doubtful or insufficiently confirmed supernovae. Sign (-) marks objects
presently rejected as supernovae. If an asterisk (*) follows the
designation, there is a remark for this object. Remarks (see file
sn_rem) indicate other cases of supernova outbursts in the same
galaxy, contain descriptions of behavior for some stars, etc. For
supernovae entering also our catalogue of extragalactic variables, there
may be a reference to Remarks of the catalogue of extragalactic
variables (see file evs_rem).

PARENT GALAXY'S DESIGNATION. Here "N" means NGC catalogue numbers,
"I" refers to the IC catalogue, "U", to the UGC catalogue, "M", to the
MCG catalogue, and "E", to ESO survey lists. The symbol "An" means an
anonymous galaxy (i.e., a galaxy absent in major catalogues of bright
galaxies), and the symbol "Intergal" is for cases when the supernova
cannot be reliably attributed to a particular galaxy and is considered
intergalactic.

EQUATORIAL CO-ORDINATES OF THE PARENT GALAXY (EQUINOX 1950.0) are
given. The standard accuracy of presented coordinates is to 0.1 s in
right ascension and to 1" in declination, but in many cases we had to
give coordinates of lower accuracy. In such cases, the column following
the coordinates contains a flag similar to those described above, in the
section devoted to the Catalogue of extragalactic variables.

GALAXY'S MORPHOLOGICAL TYPE and its INTEGRATED MAGNITUDE taken from
available sources. The integrated magnitude may be followed by a symbol
indicating the photometric band (MAGNITUDE CODE); we preferred B
magnitudes. If the photometric system symbol is missing, the magnitude
is a photographic one.

MAXIMUM MAGNITUDE (LIGHT) OF SN - the supernova's maximum brightness
date and its apparent magnitude in maximum. If a value is followed by
an asterisk (*), it means that the date and/or the magnitude refer not
to the maximum (not covered with observations), but to the EPOCH OF
DISCOVERY or to an isolated observation at high brightness. As a rule,
we did not include information about maxima if it was based on
considerable extrapolation. Lack of photometric band symbol (MAGNITUDE
CODE) indicates photographic magnitudes. If the magnitude is given with
two digits after the decimal point, it is based on photoelectric or CCD
photometry.

The positional information on the supernova itself follows. It
consists in the DISTANCE FROM THE GALAXY'S NUCLEUS TO THE SUPERNOVA in
right ascension and declination, in arcseconds, or immediately in the
SUPERNOVA'S EQUATORIAL CO-ORDINATES FOR THE EQUINOX 1950.0. The
standard accuracy of equatorial co-ordinates is the same as in the case
of parent galaxies. For a number of supernovae, information on
rectangular and on equatorial co-ordinates is not in complete agreement
if we take into account published co-ordinates of parent galaxies. To
remove such contradictions completely, it would be necessary to
determine anew and independently the co-ordinates for supernovae and
their parent galaxies. The equatorial coordinates may also have lower
accuracy flags (see above).

SUPERNOVA'S CLASSIFICATION - The system of classification for
supernovae is being permanently improved; however, we are not able to
extend the application of some recently introduced and already
frequently used types, like I-C, to supernovae discovered in earlier
years. So we have limited ourselves to the use of types I (I-A, I-B)
and II (II-l, II-pl), with possible indications of peculiarities (pec).

NAME OF THE SUPERNOVA'S DISCOVERER is given next. In cases of
several discoverers, we give the name of the first author of the
discovery followed by "+" symbol. As a rule, we did not present
information on independent rediscoveries in the remarks, for the sake of
brevity. The abbreviation "BASST" in this column means that the
supernova was discovered by the Berkeley Automated Supernova Search
Team.

BIBLIOGRAPHIC REFERENCES - three-digit numbers corresponding to the
reference list (sn_ref). The first reference is usually to the
source of photometric information. The second one is to a paper where
the galaxy's photograph with the supernova or a finding chart was
published.