Neutral Hydrogen Clouds near Early-Type Dwarf Galaxies of the Local Group

Abstract

Parkes neutral hydrogen 21 cm line (HI) observations of the surroundings of 9 early-type Local Group dwarfs are presented. We detected numerous HI clouds in the general direction of those dwarfs and these clouds are often offset from the optical center of the galaxies. Although all the observed dwarfs, except Antlia, occupy phase-space regions where the High-Velocity Cloud (HVC) density is well above average, the measured offsets are smaller than one would expect from a fully random cloud distribution. Possible association is detected for 11 of the 16 investigated clouds, while, for two galaxies, Sextans and Leo I, no HI was detected. The galaxies where HI clouds were found not to coincide with the optical, yet have a significant probability of being associated are: Sculptor dSph, Tucanna, LGS3, Cetus, and Fornax. If the clouds are indeed associated, these galaxies have HI masses of $M_{HI}=2\times 10^5{M}_{\odot }$, $M_{HI}=2\times 10^6{M}_{\odot }$, $M_{HI}=7\times 10^5{M}_{\odot }$, $M_{HI}=7\times 10^5{M}_{\odot }$, and $M_{HI}=1\times 10^5{M}_{\odot }$, respectively. However, neither ram pressure nor tidal stripping can easily explain the offsets. In some cases, large offsets are found where ram pressure should be the least effective.

arXiv commentAccepted in AJ, June 2006

References in corpus (28)

• The Structure of Cold Dark Matter Halos
• Dark Matter Substructure in Galactic Halos
• Dwarf Galaxies of the Local Group
• Efficiencies of Low-Mass Star and Star Cluster Formation
• The Parkes HI Survey of the Magellanic System
• HIPASS High-Velocity Clouds: Properties of the Compact and Extended Populations
• Gas Rich Dwarf Spheroidals
• The Star Formation History of the Carina Dwarf Galaxy
• Measuring Mass Loss Rates from Galactic Satellites
• Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal
• Exploring Halo Substructure with Giant Stars: II. Mapping the Extended Structure of the Carina Dwarf Spheroidal Galaxy
• Galactic winds and circulation of the ISM in dwarf galaxies
• A Wide-Field Survey of the Fornax Dwarf Spheroidal Galaxy
• A New Culprit in the Second Parameter Problem in the Sculptor Dwarf Spheroidal Galaxy?
• A tidal extension in the Ursa Minor dwarf spheroidal galaxy
• Star Formation Histories of Nearby Dwarf Galaxies
• Detection of HI associated with the Sculptor Dwarf Spheroidal Galaxy
• The stellar content of the Local Group dwarf galaxy Phoenix
• Radial Velocity of the Phoenix Dwarf Galaxy: Linking Gas and Hi Gas
• The Magellanic Stream and the density of coronal gas in the Galactic halo
• Detection of neutral hydrogen in early-type dwarf galaxies of the Sculptor Group
• The Absence of Extra-Tidal Structure in the Sculptor Dwarf Spheroidal Galaxy
• On the Neutral Gas Content and Environment of NGC 3109 and the Antlia Dwarf Galaxy
• The Stellar Populations of the Cetus Dwarf Spheroidal Galaxy
• WIYN Survey for Carbon Stars in the M31 and Cetus Dwarf Spheroidal Galaxies: Evolutionary Implications
• The HI environment of the Sculptor dwarf spheroidal galaxy
• HI Imaging of LGS 3 and an Apparently Interacting High-Velocity Cloud
• The Optical Velocity of the Antlia Dwarf Galaxy

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• The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies
• HI in Local Group Dwarf Galaxies and Stripping by the Galactic Halo
• The ACS LCID project. III. The star formation history of the Cetus dSph galaxy: a post-reionization fossil
• The Dearth of Neutral Hydrogen in Galactic Dwarf Spheroidal Galaxies
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. IV: Measurement for Sculptor
• M31 Satellite Masses Compared to LCDM Subhaloes
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. V: Final Measurement for Fornax
• Life at the Periphery of the Local Group: the kinematics of the Tucana Dwarf Galaxy
• Neutral Hydrogen Clouds in the M81/M82 Group
• A Deep Survey of the Fornax dSph I: Star Formation History
• Inside the whale: the structure and dynamics of the isolated Cetus dwarf spheroidal
• Reproducing properties of MW dSphs as descendants of DM-free TDGs
• A Spitzer Space Telescope Atlas of omega Centauri: The Stellar Population, Mass Loss, and the Intracluster Medium
• Spitzer Space Telescope spectral observations of AGB stars in the Fornax dwarf spheroidal galaxy
• Spatial dependence of the Star Formation History in the Central Regions of the Fornax Dwarf Spheroidal Galaxy
• Near-infrared observations of the Fornax dwarf galaxy. I. The red giant branch
• The Environmental Influence on the Evolution of Local Galaxies
• Merger traces in the spatial distribution of stellar populations in the Fornax dSph galaxy
• A Comparative Analysis of the Chemical Compositions of Gaia-Enceladus/Sausage and Milky Way Satellites using APOGEE
• Interstellar medium disruption in the Centaurus A group
• Satellites of Milky Way- and M31-like galaxies with TNG50: quenched fractions, gas content, and star formation histories
• Schwarzschild dynamical model of the Fornax dwarf spheroidal galaxy
• Rotating stellar populations in the Fornax dSph galaxy
• Extreme r-process enhanced stars at high metallicity in Fornax
• An extended stellar halo discovered in the Fornax dwarf spheroidal using Gaia EDR3
• MHONGOOSE discovery of a gas-rich low-surface brightness galaxy in the Dorado Group
• Astrophysics in 2006
• Constraining neutrino-DM interactions with Milky Way dwarf spheroidals and supernova neutrinos
• Photometric Properties of Six Local Volume Dwarf Galaxies from Deep Near-Infrared Observations
• H-alpha survey of nearby dwarf galaxies
• MIGHTEE-\HI: Possible interactions with the galaxy NGC~895
• Morphological Mutations of Dwarf Galaxies