SDSS-IV MaNGA: evidence of the importance of AGN feedback in low-mass galaxies

Abstract

We present new evidence for AGN feedback in a subset of 69 quenched low-mass\ngalaxies ($M_{\\star} \\lesssim 5\\times10^{9}$ M$_{\\odot}$, $M_{\\rm{r}} > -19$)\nselected from the first two years of the SDSS-IV MaNGA survey. The majority (85\nper cent) of these quenched galaxies appear to reside in a group environment.\nWe find 6 galaxies in our sample that appear to have an active AGN that is\npreventing on-going star-formation; this is the first time such a feedback\nmechanism has been observed in this mass range. Interestingly, five of these\nsix galaxies have an ionised gas component that is kinematically offset from\ntheir stellar component, suggesting the gas is either recently accreted or\noutflowing. We hypothesise these six galaxies are low-mass equivalents to the\n"red geysers" observed in more massive galaxies. Of the other 63 galaxies in\nthe sample, we find 8 do appear for have some low-level, residual star\nformation, or emission from hot, evolved stars. The remaining galaxies in our\nsample have no detectable ionised gas emission throughout their structures,\nconsistent with them being quenched. This work shows the potential for\nunderstanding the detailed physical properties of dwarf galaxies through\nspatially resolved spectroscopy.\n