2010/07/31 by C. Tortora, N. R. Napolitano, Aaron J. Romanowsky +3 · 2 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Cosmology and Gravitation Theories #Dark matter #Dark matter halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Physics #Redshift #Star formation #Stellar mass #Weak gravitational lensing #astro-ph.CO
paper · pdf · doi:10.1088/2041-8205/721/1/l1
5 pages, 3 figures, accepted for publication on ApJL. Version including further updates and a complementary note added in proof
arxiv created 2010/08/25 · openalex publication_date 2010/08/26 · arxiv updated 2015/05/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift ( z ∼ 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z ∼ 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano et al. and suggest negligible evidence of galaxy evolution over the last ∼2.5 Gyr other than passive stellar aging.