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MCG: Help

MCG - Morphological Galaxy Catalog


Overview

The MCG database contains the "Morphological Catalogue of Galaxies," a compilation of information for approximately 34,000 galaxies found and examined on the Palomar Observatory Sky Survey (POSS). Individual identifiers are assigned for about 29,000 galaxies and information on the remaining 5,000 is present in the extensive notes of the published catalogs (Vorontsov-Velyaminov et al. 1962-1968). The catalog is structured according to the POSS zones and is numbered from +15 (corresponding to +90 deg) to +01 (+06 deg zone) and +00 (equatorial zone) to -05 (-30 deg zone); the fields are numbered with increasing right ascension. The original goal of the compilation was to be complete for galaxies brighter than magnitude 15.1, but the final catalog lists many objects considerably fainter.

Information given in the original printed volumes includes: cross- identifications to the NGC (Dreyer 1888) and IC (Dreyer 1895, 1908) catalogs, equatorial coordinates for 1950.0, magnitude, estimated sizes and intensities of the bright inner region and the entire object, estimated inclination, and coded description (by symbols) of the appearance of the galaxy. Each field is then followed by notes on individual objects. All of the above data except the coded description are included in the machine version, except that special coding (e.g. for uncertainty or source designation) is not present (other than for the NGC/IC cross identifications [added at the Astronomical Data Center for this machine version]). Although the notes are not computerized, the presence of a note in the original is flagged in the machine version

Detailed descriptions of modifications, corrections and the record format are provided for the machine-readable version of the "Morphological Catalogue of Galaxies" (Vorontsov-Velyaminov et al. 1962-68); see the Additional Information section below. In addition to hundreds of individual corrections, a detailed comparison of the machine-readable with the published catalog resulted in the addition of 116 missing objects, the deletion of 10 duplicate records, and a format modification to increase storage efficiency.


Catalog Bibcode

1962TrSht..32....1V

References

Source Catalog Reference: Vorontsov-Velyaminov, B. A. et al., 1962-1968, 1962, Morpholoqical Trudy Gos. Astron. Inst. Shternberga

Documentation Reference: Warren Jr., W. H. 1982, NSSDC/WDC-A-R&S 82-31

Vorontsov-Velyaminov, B. A. and Krasnogorskaya, A. A. 1962, Morphological Catalogue of Galaxies, Part I, Catalogue of 7200 Galaxies from +90 to +45 deg Declination (Moscow: Sternberg Institute 32).

Vorontsov-Velyaminov, B. A. and Arhipova, A. A. 1963, Morphological Catalogue of Galaxies, Part III, Catalogue of 6740 Galaxies from +15 to -9 deg Declination (Moscow: Sternberg Institute 33).

Vorontsov-Velyaminov, B. A. and Arhipova, A. A. 1964, Morphological Catalogue of Galaxies, Part II, Catalogue of 9650 Galaxies from +45 to +15 deg Declination (Moscow: Sternberg Institute 34).

Vorontsov-Velyaminov, B. A. and Arhipova, A. A. 1968, Morphological Catalogue of Galaxies, Part IV, Catalogue of 5410 Galaxies from -9 to -33 deg Declination (Moscow: Sternberg Institute 38).

Documentation Reference: Warren Jr., W. H. 1982, NSSDC/WDC-A-R&S 82-31

Bigay, J. 1951, Ann. Astrophys. 14, 319.

Dreyer, J. L. E. 1888, New General Catalogue of Nebulae and Clusters of Stars, Mem. Roy. Astron. Soc. 49, Part I (London: Royal Astronomical Society 1962, reprinted).

Dreyer, J. L. E. 1895, Index Catalogue of Nebulae found in the Years 1888-1894, with Notes and Corrections to the New General Catalogue, Mem. Roy. Astron. Soc. 51, 185 (London: Royal Astronomical Society 1962, reprinted).

Dreyer, J. L. E. 1908, Second Index Catalogue of Nebulae and Clusters of Stars, containing Objects found in the years 1895-1907, with Notes and Corrections to the New General Catalogue and to the Index Catalogue for 1888-94, Kern. Roy. Astron. Soc. 59, Part 2, 105 (London: Royal Astronomical Society 1962, reprinted).

Holmberg, E. 1937, AM. Obs. Lund. No. 6.

Holmberg, E. 1958, Lund. Medd. 2, No. 136.

Humason, M. L., Mayall, N. U. and Sandage, A. R. 1956, Astron. J. 61, 97.

Pettit, E. 1954, Astrophys. J. 120, 413.

Reiz, A. 1941, Ann Obs. Lund. No. 9.


Additional Information

The machine readable version of the MCG was received from Dr. Robert S. Dixon of the Ohio State University Radio Observatory on 7 December 1981. As received, the catalog consisted of 28904 records of length 90 bytes. Each logical record contained a number giving the approximate sequential position of the object in the original published catalog volumes, but the machine version was ordered by right ascension. Upon listing the data and scanning some records manually, enough errors were found such that it was deemed necessary to check the records more closely.

Appreciation is expressed to B. G. Corbin of the U.S. Naval Observatory for making the published volumes of the MCG available, to Dr. R. S. Dixon of the Ohio State University Radio Observatory for supplying the original tape version, and to Dr. N. G. Roman for help with translation and interpretation of parts of the Russian preface to the published catalog.


Parameters

Name
Catalog Designation

Flag
Asterisk (*) if there is a note for this galaxy at the end of the field in the published edition; otherwise blank.

Cat_Num
Catalog number from the NGC (Dreyer 1888) or the IC (Dreyer 1895, 1908); otherwise blank. Format as follows: 'NGC' 16-18, number 20-23, component 24; 'IC' 16-17, number 19-22, component 23.

The components in byte 23 or 24 are a, b, c, etc. for components of NGC or IC object; slash (/) to denote NGC(IC) and NGC(IC) + 1 numbers together (e.g. NGC 5906/7); a colon (:) indicates an uncertain identification according to the authors (? in published catalog) [a : occurs in byte 24 in one case (MCG+10-23-065) where a / should also occur.]

RA
The Right Ascension of the object. RA Precision reported varies from whole minutes to hundredths of a minute. The greater precision is used to discriminate objects close together, but does not indicate greater accuracy.

Dec
The Declination of the object.

Mag
Magnitude taken from various sources in order of preference (Holmberg 1958; Humason, Mayall and Sandage 1956; Pettit 1954; Reiz 1941; Bigay 1951). In the published version, various symbols are used to indicate the sources above, e.g. surrounded by (), [], or //. These codes are not present in the machine version; however, magnitudes from Holmberg (1958) are reported to a hundredth and Humason et al. (1956) to a tenth. Any other coding is indistinguishable in the present machine version. Blank for missing data.

In_Maj
Diameter of the major axis of the bright inner port of the galaxy can be found in the <majaxis_in> column. This column is blank if absent. The special coding (: for uncertainty) is not present in this machine version. If only one number is given in the published version, it is given in this field and bytes 49-53 are blank. (To clarify the units, the reporting of all diameters in tenths means that MCG+15-01-001 has inner region dimensions of 0.2 x 0.05 arcmin and overall dimensions of 1.6 x 1.3 arcmin [divide diameters by ten to obtain arcminutes].)

In_Min
Diameter of the minor axis of the bright inner part of the galaxy can be found in the <minaxis_in> column. This column is blank if absent or if only one diameter is reported.

Maj_Axis
Diameter of the major axis of the entire galaxy can be found in the <majaxis> column. This column is blank if no data. The special coding (e.g. : for uncertainty) used in the published catalog is not present in the machine version. If only one number is given in the published edition (object round) it is given in this field and bytes 60-64 are blank. (The larger data field is required to accommodate M 31 at 1600 arcmin [MCG+07-02-016].)

Min_Axis
Diameter of the minor axis of the entire galaxy can be found in the <minaxis> column. This column is blank if absent or if only one diameter is reported.

Int_In
Intensity of the inner region of the galaxy I_d on a scale from 1 (completely black image) to 6 (image barely visible) can be found in the <int_in> column. This column is blank if absent.

Int_Out
Intensity of the outer region (I_D) can be found in the <int_out> column and is on same scale as above. This column is blank if absent.

Incl
Inclination of the principal Plane estimated on a scale from 1 (face on) to 5 (edge on). This column is blank if absent.

RA_1950
Right Ascension in 1950 Coordinates

Dec_1950
Declination in 1950 Coordinates

LII
The galactic latitude of the object.

BII
The galactic longitude of the object.

CRA
RA given in sexagesimal character notation, Epoch J2000 (i.e. hhmmss.s for RA and ddmmss.s for DEC).

CDec
DEC given in sexagesimal character notation, Epoch J2000 (i.e. hhmmss.s for RA and ddmmss.s for DEC).

Class
Browse Object Classification


Contact Person

Questions regarding the MCG database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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