HI clouds in the proximity of M33

Abstract

Neutral hydrogen clouds are found in the Milky Way and Andromeda halo both as large complexes and smaller isolated clouds. Here we present a search for Hi clouds in the halo of M33, the third spiral galaxy of the Local Group. We have used two complementary data sets: a 3^o x 3^o map of the area provided by the Arecibo Legacy Fast ALFA (ALFALFA) survey and deeper pointed observations carried out with the Arecibo telescope in two fields that permit sampling of the north eastern and south-western edges of the HI disc. The total amount of Hi around M33 detected by our survey is $\sim 10^7$ M${}_{\odot }$. At least 50% of this mass is made of HI clouds that are related both in space and velocity to the galaxy. We discuss several scenarios for the origin of these clouds focusing on the two most interesting ones: $(a)$ dark-matter dominated gaseous satellites, $(b)$ debris from filaments flowing into M33 from the intergalactic medium or generated by a previous interaction with M31. Both scenarios seem to fit with the observed cloud properties. Some structures are found at anomalous velocities, particularly an extended HI complex previously detected by Thilker et al. (2002). Even though the ALFALFA observations seem to indicate that this cloud is possibly connected to M33 by a faint gas bridge, we cannot firmly establish its extragalactic nature or its relation to M33. Taking into account that the clouds associated with M33 are likely to be highly ionised by the extragalactic UV radiation, we predict that the total gas mass associated with them is > 5 x 10^7 M${}_{\odot }$. If the gas is steadily falling towards the M33 disc it can provide the fuel needed to sustain a current star formation rate of 0.5 M${}_{\odot }$ yr${}^{-1}$.

16 pages, 19 figures. Accepted for publication in A&A

References in corpus (32)

• The Structure of Cold Dark Matter Halos
• Where are the missing galactic satellites?
• How Do Galaxies Get Their Gas?
• Radiative Transfer in a Clumpy Universe: II. The Utraviolet Extragalactic Background
• The Structure of Dark Matter Haloes in Dwarf Galaxies
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• High Velocity Clouds: Building Blocks of the Local Group
• The Magellanic Stream, High-Velocity Clouds and the Sculptor Group
• Cooling Radiation and the Lyman-alpha Luminosity of Forming Galaxies
• Arecibo Pulsar Survey Using ALFA. I. Survey Strategy and First Discoveries
• Dark matter and visible baryons in M33
• On the Continuing Formation of the Andromeda Galaxy: Detection of HI Clouds in the M31 Halo
• The Arecibo Legacy Fast ALFA Survey: III. HI Source Catalog of the Northern Virgo Cluster Region
• The Geometric Distance and Proper Motion of the Triangulum Galaxy (M33)
• The WSRT wide-field HI survey: II. Local Group features
• A new population of extended, luminous star clusters in the halo of M31
• Atomic Hydrogen Gas in Dark-Matter Minihalos and the Compact High Velocity Clouds
• The growth of galaxies in cosmological simulations of structure formation
• A warped disk model for M33 and the 21-cm line width in spiral galaxies
• Warps and Cosmic Infall
• The Contribution of Field OB Stars to the Ionization of the Diffuse Ionized Gas in M33
• Westerbork HI observations of high-velocity clouds near M31 and M33
• The Arecibo Legacy Fast ALFA Survey: II. Results of Precursor Observations
• Sharp Hi Edges in the Outskirts of Disk Galaxies
• The stellar halo and outer disk of M33
• An all-sky study of compact, isolated high-velocity clouds
• The building up of the disk galaxy M33 and the evolution of the metallicity gradient
• Constraints on the Proper Motion of the Andromeda Galaxy Based on the Survival of Its Satellite M33
• An extended star cluster at the outer edge of the spiral galaxy M33
• Very Luminous Carbon Stars in the Outer Disk of the Triangulum Spiral Galaxy
• Sharp HI edges at high z: the gas distribution from Damped Lyman-alpha to Lyman-limit absorption systems
• Are HVCs Produced in Galactic Fountains?

Cited by in corpus (31)

• Gaseous Galaxy Halos
• Fuel Efficient Galaxies: Sustaining Star Formation with Stellar Mass Loss
• The Disruption and Fueling of M33
• Evidence for a Massive, Extended Circumgalactic Medium Around the Andromeda Galaxy
• Dynamical signatures of a LCDM-halo and the distribution of the baryons in M33
• Discrete clouds of neutral gas between the galaxies M31 and M33
• Phased Array Feed Calibration, Beamforming and Imaging
• Kinematics of the Atomic ISM in M33 on 80 pc scales
• The Arecibo Galaxy Environment Survey V : The Virgo Cluster (I)
• Galaxy And Mass Assembly (GAMA): the red fraction and radial distribution of satellite galaxies
• The Neutral Hydrogen Bridge between M31 and M33
• Sensitive 21cm Observations of Neutral Hydrogen in the Local Group near M31
• The Arecibo Galaxy Environment Survey X: The Structure of Halo Gas Around M33
• Stellar structures in the outer regions of M33
• The faint outer regions of the Pegasus Dwarf Irregular galaxy: a much larger and undisturbed galaxy
• Triggering the formation of the supergiant H II region NGC 604 in M33
• Search for Diffuse Neutral Hydrogen and HI Clouds in the NGC 2403 Group
• Faint and fading tails : the fate of stripped HI gas in Virgo cluster galaxies
• Triangulum galaxy viewed by Planck
• Attack of the Flying Snakes : Formation of Isolated HI Clouds By Fragmentation of Long Streams
• The Origin of Neutral Hydrogen Clouds in Nearby Galaxy Groups: Exploring the Range Of Galaxy Interactions
• Rise and fall of molecular clouds across the M33 disk
• ALMA Observations of Giant Molecular Clouds in M33 III: Spatially Resolved Features of the Star-Formation Inactive Million-solar-mass Cloud
• New evidence for halo gas accretion onto disk galaxies
• The outskirts of M33: Tidally induced distortions versus signatures of gas accretion
• Neutral Gas Accretion onto Nearby Galaxies
• Accretion Onto the Milky Way: The Smith Cloud
• HI-selected Galaxies as a probe of Quasar Absorption Systems
• The Discovery and Origin of A Very-High Velocity Cloud Toward M33
• On the origin of the anomalous gas, non-declining rotation curve and disc asymmetries in NGC253
• The Widefield Arecibo Virgo Extragalactic Survey: Early Results on Known Dark Sources