Distance and mass of the M104 (Sombrero) group
  Distances and radial velocities of galaxies in the vicinity of the luminous
early-type galaxy M 104 (Sombrero) are used to derive its dark matter mass.
  Two dwarf galaxies: UGCA 307 and KKSG 30 situated near M 104 were observed
with the Advanced Camera for Surveys on the Hubble Space Telescope. The
distances $9.03^{+0.84}_{-0.51}$ Mpc (UGCA 307) and $9.72^{+0.44}_{-0.41}$ Mpc
(KKSG 30) were determined using the tip of the red giant branch method. These
distances are consistent with the dwarf galaxies being satellites of Sombrero.
  Using radial velocities and projected separations of UGCA 307, KKSG 30, and a
third galaxy with an accurate distance (KKSG 29), as well as 12 other assumed
companions with less accurate distances, the total mass of M 104 is estimated
to be $(1.55\pm0.49) 10^{13} M_{\odot}$. At the K-band luminosity of the
Sombrero galaxy of $2.4 10^{11} L_{\odot}$, its total mass-to-luminosity ratio
is $M_T/L_K = (65\pm20)M_{\odot}/L_{\odot}$, which is about three times higher
than that of luminous bulgeless galaxies.
