Kavli Affiliate: Risa H. Wechsler
| First 5 Authors: Marla Geha, Yao-Yuan Mao, Risa H. Wechsler, Yasmeen Asali, Erin Kado-Fong
| Summary:
We present the star-forming properties of 378 satellite galaxies around 101
Milky Way analogs in the Satellites Around Galactic Analogs (SAGA) Survey,
focusing on the environmental processes that suppress or quench star formation.
In the SAGA stellar mass range of 10^6 to 10^10 solar masses, we present
quenched fractions, star-forming rates, gas-phase metallicities, and gas
content. The fraction of SAGA satellites that are quenched increases with
decreasing stellar mass and shows significant system-to-system scatter. SAGA
satellite quenched fractions are highest in the central 100 kpc of their hosts
and decline out to the virial radius. Splitting by specific star formation rate
(sSFR), the least star-forming satellite quartile follows the radial trend of
the quenched population. The median sSFR of star-forming satellites increases
with decreasing stellar mass and is roughly constant with projected radius.
Star-forming SAGA satellites are consistent with the star formation
rate–stellar mass relationship determined in the Local Volume, while the
median gas-phase metallicity is higher and median HI gas mass is lower at all
stellar masses. We investigate the dependence of the satellite quenched
fraction on host properties. Quenched fractions are higher in systems with
larger host halo mass, but this trend is only seen in the inner 100 kpc; we do
not see significant trends with host color or star formation rate. Our results
suggest that lower mass satellites and satellites inside 100 kpc are more
efficiently quenched in a Milky Way-like environment, with these processes
acting sufficiently slowly to preserve a population of star-forming satellites
at all stellar masses and projected radii.
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