The stellar mass in and around isolated central galaxies: connections to the total mass distribution through galaxy-galaxy lensing in the Hyper Suprime-Cam survey

Kavli Affiliate: Naoki Yasuda

| First 5 Authors: Wenting Wang, Xiangchong Li, Jingjing Shi, Jiaxin Han, Naoki Yasuda

| Summary:

Using photometric galaxies from the HSC survey, we measure the stellar mass
density profiles for satellite galaxies as a function of the projected
distance, $r_p$, to isolated central galaxies (ICGs) selected from SDSS/DR7
spectroscopic galaxies at $zsim0.1$. By stacking HSC images, we also measure
the projected stellar mass density profiles for ICGs and their stellar halos.
The total mass distributions are further measured from HSC weak lensing
signals. ICGs dominate within $sim$0.15 times the halo virial radius
($0.15R_{200}$). The stellar mass versus total mass fractions drop with the
increase in $r_p$ up to $sim0.15R_{200}$, beyond which they are less than 1%
while stay almost constant, indicating the radial distribution of satellites
trace dark matter. The total stellar mass in satellites is proportional to the
virial mass of the host halo, $M_{200}$, for ICGs more massive than
$10^{10.5}M_odot$, i.e., $M_{ast,mathrm{sat}} propto M_{200}$, whereas the
relation between the stellar mass of ICGs $+$ stellar halos and $M_{200}$ is
close to $M_{ast,mathrm{ICG+diffuse}}propto M_{200}^{1/2}$. Below
$10^{10.5}M_odot$, the change in $M_{200}$ is much slower with the decrease in
$M_{ast,mathrm{ICG+diffuse}}$. At fixed stellar mass, red ICGs are hosted by
more massive dark matter halos and have more satellites. At
$M_{200}sim10^{12.7}M_odot$, both $M_{ast,mathrm{sat}}$ and the fraction of
stellar mass in satellites versus total stellar mass, $f_mathrm{sat}$, tend to
be slightly higher around blue ICGs, perhaps implying the late formation of
blue galaxies. $f_mathrm{sat}$ increases with the increase in both
$M_{ast,mathrm{ICG+diffuse}}$ and $M_{200}$, and scales more linearly with
$M_{200}$. We provide best-fitting formulas for these scaling relations and for
red and blue ICGs separately.

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