Abstract
We select satellite galaxies from the galaxy group catalogue constructed with the Sloan Digital Sky Survey spectroscopic galaxies and measure the tangential shear around these galaxies with the source catalogue extracted from the Canada–France–Hawaii Telescope Stripe-82 Survey. Using the tangential shear, we constrain the mass of subhaloes associated with these satellites. The lensing signal is measured around satellites in groups with masses in the range 1013−5 × 1014h−1 M⊙, and is found to agree well with theoretical expectations. Fitting the data with a truncated NFW profile, we obtain an average subhalo mass of log (Msub/h−1 M⊙) = 11.68 ± 0.67 for satellites whose projected distances to central galaxies are in the range 0.1−0.3 h−1 and log (Msub/h−1 M⊙) = 11.68 ± 0.76 for satellites with projected halo-centric distance in [0.3, 0.5] h−1 Mpc. The best-fitting subhalo masses are comparable to the truncated subhalo masses assigned to satellite galaxies using abundance matching and are about 5–10 times higher than the average stellar mass of the lensing satellite galaxies.
Highlights
According to the cold dark matter (CDM) paradigm of structure formation, dark matter haloes form hierarchically through merging and accretion, while galaxies form at the centres of dark matter haloes through gas accretion and star formation
We have used the Y07 galaxy group catalogue constructed from the Sloan Digital Sky Survey (SDSS) spectroscopic survey to select satellite galaxies and obtained tangential shears around them using sources selected from the CFHT Stripe-82 Survey (CS82)
This has resulted in a direct measurement of the gravitational lensing effect due to dark matter subhaloes associated with satellite galaxies
Summary
According to the cold dark matter (CDM) paradigm of structure formation, dark matter haloes form hierarchically through merging and accretion, while galaxies form at the centres of dark matter haloes through gas accretion and star formation. In Li et al (2013, hereafter L13), we have proposed a method to measure the galaxy–galaxy lensing effect of subhaloes by using satellite galaxies selected from galaxy groups identified from the SDSS spectroscopic catalogue (Yang et al 2005, 2007). With such a group catalogue, one cannot only distinguish satellites from centrals and select lensing satellite galaxies both according to their host halo masses and their projected distances to the host halo centre. Throughout the paper, we adopt a CDM cosmology with parameters given by the WMAP 7-year data (Komatsu et al 2011)
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