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Researchers identified 127 gas-containing dwarf galaxies orbiting 56 larger galaxies within 30 million parsecs of Earth using radio telescope data. These satellite galaxies show lower gas fractions than previously studied samples and appear in small numbers around their host galaxies (0-2 around dwarf hosts, 0-5 around Milky Way-sized hosts). The findings indicate that environmental processes effectively remove gas from these satellite galaxies, suppressing their star formation when they orbit within Milky Way-mass galactic systems.
Why it matters
This study provides observational evidence for how galaxies lose their gas and stop forming stars when influenced by their larger galactic neighbors. Understanding these environmental quenching processes helps explain why dwarf galaxies in different cosmic environments evolve differently and contributes to models of galaxy formation and evolution.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: We present a sample of 127 gas-bearing dwarf galaxies around 56 late-type host galaxies within 30 Mpc using 21-cm HI data from the WALLABY, MHONGOOSE, and ALFALFA surveys. We characterize the environment of each dwarf galaxy based on its host galaxy halo and derive optical properties using the DESI Legacy Surveys for 110. The gaseous satellites span $log (M_{rm HI}/M_{odot}) = 5.8-9.7$ and $log (M_{star}/M_{odot}) = 5.6-10.0$, with a median velocity line-width of $W_{50}=40$ km/s, comparable to the Local Group gaseous dwarf galaxies. We assess the HI mass sensitivity of the data by injecting model dwarf galaxies and find $M_{rm HI,lim} approx 10^{6.7} M_{odot}$ for WALLABY and $M_{rm HI,lim} approx 10^{5.4} M_{odot}$ for MHONGOOSE at 10 Mpc. Our sample has lower average atomic gas fractions ($M_{rm HI}/M_{star}$) than previous gaseous dwarf samples in field and satellite environments, although this offset partly reflects differences in HI sensitivity. The abundance of gaseous satellites per host is low and increases with host mass: $0-2$ for dwarf centrals and $0-5$ for Milky Way-mass spiral hosts. These numbers are consistent with the Milky Way, M31, and star-forming satellite abundances from recent deep optical surveys. The inferred quenched fractions and gas-depleted satellites indicate that environmental quenching is effective in Milky Way-mass hosts, likely driven by gas stripping processes.
Source: Baryonic Masses and Properties of Gaseous Satellite Galaxies