The Effects of Halo-to-halo Variation on Substructure Lensing
Abstract
We explore the halo-to-halo variation of dark matter (DM) substructure in galaxy-sized DM halos, focusing on its implications for strongly gravitational lensed systems. We find that the median value for projected substructure mass fractions within projected radii of 3% of the host halo virial radius is approximately f sub ≈ 0.25%, but that the variance is large with a 95 percentile range of 0 <= f sub <= 1%. We quantify possible effects of substructure on quadruply imaged lens systems using the cusp relation and the simple statistic, R cusp. We estimate that the probability of obtaining the large values of the R cusp which have been observed from substructure effects is roughly ~10-3 to ~10-2. We consider a variety of possible correlations between host halo properties and substructure properties in order to probe possible sample biases. In particular, low-concentration host DM halos have more large substructures and give rise to large values of R cusp more often. However, there is no known observational bias that would drive observed quadruply imaged quasars to be produced by low-concentration lens halos. Finally, we show that the substructure mass fraction is a relatively reliable predictor of the value of R cusp.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2011
- DOI:
- 10.1088/0004-637X/741/2/117
- arXiv:
- arXiv:1101.2916
- Bibcode:
- 2011ApJ...741..117C
- Keywords:
-
- cosmology: theory;
- dark matter;
- galaxies: halos;
- gravitational lensing: strong;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 14 pages, 10 figures. Replaced with version accepted for publication in ApJ. Minor changes from version 1