Abstract
We use weak gravitational lensing to analyse the dark matter halos around
satellite galaxies in galaxy groups in the CFHTLenS dataset. This dataset is
derived from the CFHTLS-Wide survey, and encompasses 154 sq. deg of
high-quality shape data. Using the photometric redshifts, we divide the sample
of lens galaxies with stellar masses in the range 10^9 Msun to 10^10.5 Msun
into those likely to lie in high-density environments (HDE) and those likely to
lie in low-density environments (LDE). Through comparison with galaxy
catalogues extracted from the Millennium Simulation, we show that the sample of
HDE galaxies should primarily (~61%) consist of satellite galaxies in groups,
while the sample of LDE galaxies should consist of mostly (~87%) non-satellite
(field and central) galaxies. Comparing the lensing signals around samples of
HDE and LDE galaxies matched in stellar mass, the lensing signal around HDE
galaxies clearly shows a positive contribution from their host groups on their
lensing signals at radii of ~500--1000 kpc, the typical separation between
satellites and group centres. More importantly, the subhalos of HDE galaxies
are less massive than those around LDE galaxies by a factor 0.65 +/- 0.12,
significant at the 2.9 sigma level. A natural explanation is that the halos of
satellite galaxies are stripped through tidal effects in the group environment.
Our results are consistent with a typical tidal truncation radius of ~40 kpc.
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