HyperLEDA documentation: Photometry from growth curve fitting

Asymptotic photometry of galaxies in U B V R and I

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The catalogue of aperture photometry of galaxies in U B V R and I

The present catalogue continues the compilations published by G. Longo & A. de Vaucouleurs (1983, 1988 Monographs of University of Austin). The first version (1983) may be obtained from CDS.

We have updated this catalogue by scanning the literature and extended it by adding aperture photometry derived from published surface photometry. We also included our own unpublished measurements.

The catalogue and derived magnitudes and colours are presented in Prugniel and Héraudeau 1998, A&AS 128, 299

The catalogue contains 34675 aperture measurements from diaphragm photometry and 72336 derived from surface photometry or image analysis on a total of 7567 galaxies.

The catalogue can be searched through HyperLeda (search by name or coordinates, download...), and is also available from CDS.

Global photometric parameters

We used the catalogue of aperture photometry to derive global photometric parameters from growth curve fitting. This work is described in the paper cited above. The results presented in HyperLeda are:

Asymptotic (or total) magnitude in the B band
Mean surface brightness within the effective aperture
Photometric type
Colors at the effective radius:
- B-V
- U-B
- V-R
- V-I
Quality class

(Note the effective aperture Ae can be derived from Bt and SBe as: 5*log(Ae)=SBe - Bt - 4.38, where Ae is expressed in 0.1 arcmin)

The set of curves of growth finally used is an interpolation between exponential and de Vaucouleurs profiles. The interpolation parameter is connected to the photometric type, defined to match the morphologic type (except for the diffuse elliptical galaxies for which the morphological type is -5 while the photometric type is around +10).

This work extends the effort developed for the production of the RC3 catalogue and published in:

Buta et al. (1995) ,for the U B and V
Buta and Williams (1995), for R and I

Interesting links

Photometric standards (Ricky Patterson)
Secondary Photometric Standard Stars for the Thuan-Gunn and Johnson-Kron-Cousins Systems (Inger Joergensen).
Asiago Database on Photometric Systems

HyperLeda Questions: leda@univ-lyon1.fr