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DENISIGAL: Help

DENISIGAL - First DENIS I-band Extragalactic Catalog


Overview

This database contains the release of the provisional extragalactic catalog constructed from the "Deep Near Infrared Southern Sky Survey" (DENIS) and is sometimes referred to as REDCAT (Rapid Extraction from DENIS Catalog). It was created using an automatic galaxy recognition program based on a discriminating analysis, the efficiency of which is estimated to be better than 99%. The nominal accuracy for galaxy coordinates calculated with the Guide Star Catalog is about 6 arcseconds. The cross-identification with galaxies available in the Lyon-Meudon Extragalactic DAtabase (LEDA) allows a calibration of the I-band photometry with the sample of Mathewson et al. (1992, ApJS, 81, 413) and Mathewson and Ford (1996, ApJS, 107, 97). Thus, the catalog contains total I-band magnitude, isophotal diameter, axis ratio, position angle and a rough estimate of the morphological type code for 20620 galaxies. The internal completeness of this catalog reaches a limiting I-band magnitude of 14.5, with a photometric accuracy of 0.18 mag. 25% of the Southern sky has been processed in this study.

Catalog Bibcode

1999A&AS..135..133V

References

First DENIS I-band extragalactic catalog Vauglin I., Paturel G., Borsenberger J., Fouque P., Epchtein N., Kimeswenger S., Tiphene D., Lanoix P., Di Nella-Courtois H. <Astron. Astrophys. Suppl. Ser. 135, 133 (1999)> =1999A&AS..135..133V (SIMBAD/NED BibCode)

Provenance

This database was created by the HEASARC in July 1999 based on a machine-readable version that was obtained form the CDS Data Center.

Parameters

Name
The DENIS identifier.

Pgc
The LEDA identifier. This number is identical to the Principal Galaxies Catalog or PGC (Paturel et al. 1989, A&AS, 80, 200 = CDS Cat. <VII/119>) number for LEDA number less than 73197. It is useful for retrieving a galaxy from the LEDA database.

Alt_Name
An alternate name, according to the hierarchy NGC, IC, ESO, UGC, MCG, and other miscellaneous catalogs.

RA
Right Ascension in the default equinox. The original data were provided in J2000 coordinates, with the RA specified to 0.1 seconds.

Dec
Declination in the default equinox. The original data were provided in J2000 coordinates, with the declination specified to 1 arcsecond.

LII
Galactic longitude.

BII
Galactic latitude.

Imag
The DENIS I-band total magnitude calibrated by comparison with the I-band measurements of Mathewson at al. (1992, ApJS, 81, 413) and Mathewson and Ford (1996, ApJS, 107, 97)

Log_D
The log to the base 10 of the isophotal diameter D, where D is in units of 0.1 arcminutes, following the notation of de Vaucouleurs et al. in the Reference Catalogs of Bright Galaxies.

Log_A_Over_B
The log to the base 10 of the isophotal axis ratio R, where R is the ratio of the major (a) to the minor axis (b).

Position_Angle
The position angle beta in degrees, measured from North Eastwards. Its value lies bewteen 0 and 180 degrees (excluding 180). For galaxies for which log R = log (a/b) < 0.5, the significance of beta is low, as is reflected by the size of its associated mean error.

Morph_Type
The photometric morphological type code T. The coding is given according to RC2, the 2nd Reference Catalog of Bright Galaxies, and ranges from -5 for elliptical to +10 for irregular galaxies.

Num_Measures
A quality code that gives information on the number of independent measurements (by summing the digits) and on the quality of each measurement (from their power of ten). The quality codes are: 1 for normal' galaxies, 10 for 'peculiar galaxies, 100 for 'multiple' galxies, and 1000 for 'truncated' galaxies, and this code is the sum of individual measurements. (Notice that 'truncated' galaxies will have overestimated magnitudes, while, on the contrary, 'multiple' galaxies will have underestimated magnitudes). For example, a value of 1002 means that there are 1 truncated measurement and 2 normal ones, for a total of 3 independent measurements.

Error_Radius
The mean error in the position, in arcseconds.

Imag_Error
The mean error in the I magnitude, Imag.

Log_D_Error
The mean error in log10 of the isophotal diameter D, where D is in units of 0.1 arcminutes.

Log_A_Over_B_Error
The mean error in the log10 of the isophotal axis ratio R = (a/b).

Position_Angle_Error
The mean error in the position angle, in degrees.

Morph_Type_Error
The mean error in the photometric morphological type.


Contact Person

Questions regarding the DENISIGAL 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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