The velocity dispersion function of early-type galaxies

Authors :: Sheth, Ravi K.
Bernardi, M.
Schechter, P. L.
Burles, S.
Eisenstein, D. J.
Finkbeiner, D. P.
Frieman, J.
Hogg, D. W.
Lupton, R. H.
Schlegel, D. J.
Subbarao, M.
Shimasaku, K.
Bahcall, N. A.
Brinkmann, J.
Ivezic, Z.
Sheth, Ravi K.
Bernardi, M.
Schechter, P. L.
Burles, S.
Eisenstein, D. J.
Finkbeiner, D. P.
Frieman, J.
Hogg, D. W.
Lupton, R. H.
Schlegel, D. J.
Subbarao, M.
Shimasaku, K.
Bahcall, N. A.
Brinkmann, J.
Ivezic, Z.
Publication Year :: 2003
Abstract: The distribution of early-type galaxy velocity dispersions, phi(sigma), is measured using a sample drawn from the SDSS database. Its shape differs significantly from that which one obtains by simply using the mean correlation between luminosity, L, and velocity dispersion, sigma, to transform the luminosity function into a velocity function: ignoring the scatter around the mean sigma-L relation is a bad approximation. An estimate of the contribution from late-type galaxies is also made, which suggests that phi(sigma) is dominated by early-type galaxies at velocities larger than ~ 200 km/s.<br />Comment: Minor changes, matches version to appear in ApJ, 1 September 2003