Article Dans Une Revue The Astrophysical Journal Année : 2009

Dwarf Galaxy Clustering and Missing Satellites

R. G. Carlberg
  • Fonction : Auteur
M. Sullivan
  • Fonction : Auteur
D. Le Borgne

Résumé

At redshifts around 0.1 the Canada-France-Hawaii Telescope Legacy Survey Deep fields contain some 6 × 104 galaxies spanning the mass range from 105 to 1012 M sun. We measure the stellar mass dependence of the two-point correlation using angular measurements to largely bypass the errors, approximately 0.02 in the median, of the photometric redshifts. Inverting the power-law fits with Limber's equation we find that the autocorrelation length increases from a very low 0.4 h -1 Mpc at 105.5 M sun to the conventional 4.5 h -1 Mpc at 1010.5 M sun. The power-law fit to the correlation function has a slope which increases from γ sime 1.6 at high mass to γ sime 2.3 at low mass. The spatial cross-correlation of dwarf galaxies with more massive galaxies shows fairly similar trends, with a steeper radial dependence at low mass than predicted in numerical simulations of subhalos within galaxy halos. To examine the issue of "missing satellites" we combine the cross-correlation measurements with our estimates of the low-mass galaxy number density. We find on the average there are 60 ± 20 dwarfs in subhalos with M(total)>107 M sun for a typical Local Group M(total)/M(stars) = 30, corresponding to M/LV sime 100 for a galaxy with no recent star formation. The number of dwarfs per galaxy is about a factor of 2 larger than currently found for the Milky Way. Nevertheless, the average dwarf counts are about a factor of 30 below lambda cold dark matter (LCDM) simulation results. The divergence from LCDM predictions is one of the slope of the relation, approximately dN/dln M sime -0.5 rather than the predicted -0.9, not sudden onset at some characteristic scale. The dwarf galaxy star formation rates span the range from passive to bursting, which suggests that there are few completely dark halos.

Dates et versions

hal-03646311 , version 1 (19-04-2022)

Identifiants

Citer

R. G. Carlberg, M. Sullivan, D. Le Borgne. Dwarf Galaxy Clustering and Missing Satellites. The Astrophysical Journal, 2009, 694, pp.1131-1138. ⟨10.1088/0004-637X/694/2/1131⟩. ⟨hal-03646311⟩
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