Census of gaseous satellites around local spiral galaxies

Abstract

ABSTRACTWe present a search for gas-containing dwarf galaxies as satellite systems around nearby spiral galaxies using 21 cm neutral hydrogen (H i) data from the Arecibo Legacy Fast ALFA (ALFALFA) Survey. We have identified 15 spiral ‘primary’ galaxies in a local volume of 10 Mpc with a range of total masses, and have found 19 gas-containing dwarf satellite candidates within the primaries’ virial volumes (R200) and 46 candidates within 2R200. Our sensitivity using ALFALFA data converts to MH i ≈ 7.4 × 106 M⊙ at 10 Mpc, which includes 13 of the 26 gaseous dwarf galaxies in the Local Group, and the H i properties of our sample are overall similar to these 13. We found 0–3 gaseous satellites per host galaxy within R200 and 0–5 within 2R200, which agrees with the low numbers present for the Milky Way and M31. There is also agreement with the star-forming satellite numbers per host in the deep optical surveys SAGA and ELVES, and the Auriga cosmological simulations. When scaled to R200, the optical surveys do not show a trend of increasing quenched fraction with host mass; there is a slight increase in the total number of gaseous satellites with host mass for our sample. The low numbers of gaseous/star-forming satellites around spiral hosts are consistent with the idea that a universal and effective satellite quenching mechanism, such as ram pressure stripping by the host halo, is likely at play.