Compilation of photometry

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This catalogue (table a107 in the database) presents the compilation of apparent fluxes (magnitudes) of galaxies. They are collected from the litterature and from surveys and are not corrected for Galactic extinction or for any other effect.

As a short introduction, see this article on astronomical magnitude systems (by Wirth) and this one on magnitude of galaxies (from NED).
Read the review article Standard Photometric Systems (Bessell 2005), and consult the Asiago Database on Photometric Systems (Munary) and the General Catalogue of Photometric Data (Mermillod).

Some other resources:
Magnitude System and Color Conversion Formulas (Seiichi Yoshida)
Conversions between Johnson and AB magnitudes: Frei and Gunn 1995
Conversions between Vega and AB magnitudes: Blanton et al., Astronomical Journal 127, 2562-2578 (2005), eqs.(5))

In March 2006, the table counted 8.6 million measurements (in any color band) for 1.65 million galaxies.

Description of the fields

Field: mag

Magnitude with its uncertainty and quality flag in parentheses. The uncertainty flag (2) indicates a detection limit (the flux is fainter than the given value). Fluxes originally given in physical flux density are converted into AB magnitude (eg. mag_AB = -2.5 * log(flux/mJy) + 16.4 ).

Field: loga

Logarithm of aperture used for aperture photometry.
The diameter of the aperture is measured in 0.1 arcmin (e.g. logA=1 means that the aperture diameter is 1 arcmin)

Field: iso

Isophote: isophotal limiting surface brightness for isophotal magnitude in mag.arcsec^-2

Field: bandname

Photometric Band. The definitions are given in the band_codes table:

Field: tel

Telescope. Used for 21cm flux corrections during the homogenisation. The definitions are given in the "telescopes_codes" table:

Field: code_mag

Code for the type of magnitude as given in the"mag_codes" table:

Field: correction

Field: quality