|Compilation of diameters|
This catalogue (table a106 in the database) presents the compilation of apparent diameters of galaxies. They are collected from the litterature and from surveys and are not corrected for Galactic extinction or for any other effect.
These raw diameters are used to derive
They are also used for evaluating the mean surface brightnesses and corrections in the computation of some other mean parameters. See also the article on size of galaxies from the NED knowledge database (Level 5).
In March 2006, the table counted 3.1 million measurements for 1.2 million galaxies.
Major Axis: decimal log of major axis log D (D in
arcmin) with uncertainty
and quality flag in parentheses
(For instance, if the major axis logD=1, it means
that D=10 in 0.1', i.e. D=1').
Minor Axis: decimal log of minor
axis logd (d in 0.1 arcmin)
Isophote: isophotal level in mag.arsec-2 for isophotal diameters
Diameter Code: code for the type of diameter following "dcode" table:
Photometric Band. The definitions are given in the "band_codes" table:
|description of quality flag|
|1||uncertain measurement, its weight is decreased by a factor 2 when computing the average value|
|3||preliminary measurement, probably superseeded in a more recent publication, it is ignored unless no other measurement is available|
|4||compilation, it is ignored unless no other measurement is available|