Using the first 25 % of DEEP2 Redshift Survey data , we probe the line-of-sight velocity dispersion profile for isolated galaxies with absolute B-band magnitude -22 < M _ { B } -5 \log ( h ) < -21 at z =0.7-1.0 , using satellite galaxies as luminous tracers of the underlying velocity distribution .
Measuring the velocity dispersion beyond a galactocentric radius of \sim 200 h ^ { -1 } kpc ( physical ) permits us to determine the total mass , including dark matter , around these bright galaxies .
Tests with mock catalogs based on N-body simulations indicate that this mass measurement method is robust to selection effects .
We find a line-of-sight velocity dispersion ( \sigma _ { los } ) of 162 ^ { +44 } _ { -30 } km s ^ { -1 } at \sim 110 h ^ { -1 } kpc , 136 ^ { +26 } _ { -20 } km s ^ { -1 } at \sim 230 h ^ { -1 } kpc , and 150 ^ { +55 } _ { -38 } km s ^ { -1 } at \sim 320 h ^ { -1 } kpc .
Assuming an NFW model for the dark matter density profile , this corresponds to a mass within r _ { 200 } of M _ { 200 } = 5.5 ^ { +2.5 } _ { -2.0 } \times 10 ^ { 12 } h ^ { -1 } M _ { \sun } for our sample of satellite hosts with mean luminosity \sim 2.5 L ^ { \ast } .
Roughly \sim 60 \% of these host galaxies have early-type spectra and are red in restframe ( U - B ) color , consistent with the overall DEEP2 sample in the same luminosity and redshift range .
The halo mass determined for DEEP2 host galaxies is consistent with that measured in the Sloan Digital Sky Survey for host galaxies within a similar luminosity range relative to M ^ { \ast } _ { B } .
This comparison is insensitive to the assumed halo mass profile , and implies an increase in the dynamical mass-to-light ratio ( M _ { 200 } / L _ { B } ) of isolated galaxies which host satellites by a factor of \sim 2.5 from z \sim 1 to z \sim 0 .
Our results can be used to constrain the halo occupation distribution and the conditional luminosity function used to populate dark matter halos with galaxies .
In particular , our results are consistent with scenarios in which galaxies populate dark matter halos similarly from z \sim 0 to z \sim 1 , except for \sim 1 magnitude of evolution in the luminosity of all galaxies .
With the full DEEP2 sample , it will be possible to extend this analysis to multiple luminosity or color bins .