Catalog galaxies

Following the example catalogs of stars, the catalogs of galaxies are compilation of the positions and certain properties of Galaxie S.

The interest of the catalogs of galaxies is that they make it possible to carry out statistics on these populations of objects. In Cosmology, it is especially their space distribution which is the their interest object. It is necessary for that not only to know their position on the celestial Sphère, but also their distance. In practice, one measures to primarily them Décalage towards the red, which one can then translate into term of distance by using the parameters cosmological Modèle subjacent. In certain cases, the measurement of the shift towards the red by Spectroscopie, although specifies, is too long to carry out. One then measures it by photometric methods .

Just like the star catalogs, the catalogs of galaxies in general cover a limited area of the sky and limit to some maximum magnitude. Certain catalogs of galaxies are focused on certain specific types of galaxies, as the active galaxies (Catalog Markarian, for example).

Some catalogs of galaxies

Catalog Arp, list some irregular galaxies or in interaction
Catalog Markarian, list of the active galaxies
Catalog Abel, list of the Galaxy cluster
General Catalog of Uppsala
Catalog APM
Catalog 2dF, including/understanding approximately 250 000 galaxies and 23 000 Quasar S
Sloan DIGITAL Sky Survey, including/understanding approximately 675 000 galaxies and 90 000 quasars

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