Subaru HSC weak lensing of SDSS redMaPPer cluster satellite galaxies: empirical upper limit on orphan fractions

Abstract

ABSTRACT Weak gravitational lensing directly probes the matter distribution surrounding satellite galaxies in galaxy clusters. We measure the weak lensing signal induced on the shapes of background galaxies around the Sloan Digital Sky Survey (SDSS) redMaPPer cluster satellite galaxies, which have their central galaxies assigned with a probability Pcen > 0.95 in the redshift range, 0.1 ≤ z ≤ 0.33. We use the galaxy shapes from the Subaru Hyper Suprime-Cam (HSC) survey for this purpose. We bin satellite galaxies by their distance from the cluster centre and compare it to the signal around a control sample of galaxies that do not reside in clusters but have similar colours and magnitudes. We explore the effect of environmental processes on the dark matter mass around satellites. We see hints of a difference in the mass of the subhalo of the satellite compared to the halo masses of galaxies in our control sample, especially in the innermost cluster-centric radial bin (0.1 < r < 0.3 [${h^{-1}\,\rm Mpc}$]). For the first time, we put an upper limit on the prevalence of orphan galaxies that have entirely lost their dark matter haloes with cluster-centric distances with the help of our measurements. However, these upper limits could be relaxed if there is substantial contamination in the satellite galaxy sample.