Abstract
It has been known for decades that satellite galaxies are always less star forming than central galaxies of similar mass. New, sophisticated modeling of satellites at both z = 0 and z = 1 has shown that the quenching of star formation in satellites must be a rapid process, occurring on a timescale of only ~ 0.5 Gyr. Despite good constraints on the quenching timescale, the detailed physics of how satellites actually shut down their star formation is still heavily debated. What is now desperately needed are high-quality observations of satellite galaxies directly in the process of quenching. In particular, resolved H-alpha maps would be extremely informative because H-alpha is a near instantaneous measure of the current SFR, showing where and when star formation is quenched. Thus far, these maps are only available locally for satellite galaxies in the Virgo cluster; however, they are fascinating. In H-alpha emission Virgo satellites are completely different than central galaxies, with >50% having highly truncated and disturbed disks, suggesting an outside-in truncation of star formation. We propose to obtain the first resolved H-alpha maps of star-forming satellite galaxies in massive clusters at z ~ 1. This high-redshift data will be critical to determine how satellite quenching evolves over time, as satellites have much higher gas fractions and star formation rates at z ~ 1. We will compare the H-alpha luminosities, sizes and profiles of the satellites to central galaxies in the 3D-HST survey and quantify how quenching affects star-forming disks at z ~ 1. This information will be key input for the next generation of physical models of satellite quenching.
Original language | English |
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Publication status | Published - 1 Nov 2015 |