Evolution in the HALO Masses of Isolated Galaxies between Z~;1 andZ~;0: From Deep2 to SDSS
We measure the evolution in the virial mass-to-light ratio(M_200/L_B) and virial-to-stellar mass ratio (M_200/M*) for isolated ~;L*galaxies between z~;1 and z~;0 by combining data from the DEEP2 GalaxyRedshift Survey and the Sloan Digital Sky Survey. Utilizing the motionsof satellite galaxies around isolated galaxies, we measure line-of-sightvelocity dispersions and derive dark matter halo virial masses for thesehost galaxies. At both epochs the velocity dispersionof satellitescorrelates with host galaxy stellar mass, with sigma prop M*(0.4+-0.1),while the relation between satellite velocity dispersion and host galaxyB-band luminosity may grow somewhat shallower, from sigma propL_B(0.6+-0.1) at z~;1 to sigma proportional to L_B(0.4+-0.1) at z~;0. Theevolution in M_200/M* from z~;1 to z~;0 displays a bimodality, insofar ashost galaxies with stellar mass below M*~;1011 h-11M_Sub maintain aconstant ratio (the intrinsic increase is constrained to a factor of1.1+-0.5) while host galaxies above this mass experience a factor of3.3+-2.2 increase in their virial-to-stellar mass ratio. This result canbe easily understood if galaxies below this stellar mass scale continueto form stars while star formation in galaxies above this scale isquenched and the dark matter halos of galaxies both above and below thisscale grow in accordance with LCDM cosmological simulations. Hostgalaxies that are red in U - B color have larger satellite dispersionsand hence reside on average in more massive halos than blue galaxies atboth z~;1 and z~;0. The satellite population of host galaxies varieslittle between these epochs; the only significant difference is thatsatellites at z~;1 tend to be comparatively fainter (by ~;0.15 magnitudesin the mean) relative to their host luminosity than satellites at z ~; 0.The redshift and host galaxy stellar mass dependence of M_200/M* agreesqualitatively with the Millennium Run semi-analytic model of galaxyformation.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science; National Aeronautics andSpace Administration
- DOE Contract Number:
- DE-AC02-05CH11231; NASA:HST-HF-01165
- OSTI ID:
- 919386
- Report Number(s):
- LBNL-61742; ASJOAB; R&D Project: PHFJN; BnR: 400409900; TRN: US0806368
- Journal Information:
- The Astrophysical Journal, Vol. 654, Issue 1pt1; Related Information: Journal Publication Date: 01/01/2007; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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