Where Are the High-Velocity Clouds?

By Vicent Quilis, B. Moore. 2001

176 citations recorded by the source corpus.

Recent observations of high-velocity clouds (HVCs) have revealed compression fronts and tail-shaped features of H I, suggesting that they are interacting with an external medium. We perform three-dimensional hydrodynamical simulations of HVCs moving through a diffuse hot gaseous component, investigating the behavior of both extragalactic dark matter-dominated HVCs and nearby pure gas clouds that may be accreting onto the Galactic disk via a Galactic fountain. Both scenarios can give rise to similar features as observed if the external medium has a density greater than 10-4 cm-3. Observations suggest that this may be too high for a hot ionized halo or intergalactic gas and supports the Galactic fountain origin, a model that can also account for the high fraction of HVCs with tails and asymmetrical morphologies.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/d52828d6af54cb957488f93eddc05ecd8542f5f9

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Citations in the corpus

Simultaneous ram pressure and tidal stripping; how dwarf spheroidals lost their gas (2005, background): “…has been widely stud- ied for galaxies in clusters in a number of numerical works since the early 80s, among them Farouki & Shapiro (1980), Toyama & Ikeuchi (1980), Vollmer et al. (1999, 2000, 2001), Schulz & Struck (2001), Abadi, Moore & Bower (1999), Quilis & Moore (2001) and Vollmer (2003).”
Star formation sustained by gas accretion (2014, background): “Extra-planar gas is also found in our own galaxy, where the existence of gas clouds falling in is long known (Oort 1966; Blitz et al. 1999; van Woerden et al. 2004; Wakker et al. 2007, 2008).”
Multiphase High-Velocity Clouds toward HE 0226–4110 and PG 0953+414 (2005, background): “…UV (S03; Fox et al. 2004; Collins et al. 2004, 2005; Ganguly et al. 2005) and X-ray high-ion absorption (Fang et al. 2003; McKernan et al. 2004) studies and from pulsar dispersion measures, X-ray emission, and properties of the Magellanic Stream (see Quilis & Moore 2001 and references therein).”
Gaseous Galaxy Halos (2012, background): “Without accretion, the SFRs indicate the star formation fuel currently in the disk will last for another few Gyrs at most.”
Dark matter in the Milky Way II. The HI gas distribution as a tracer of the gravitational potential (2007, background): “In addition, stellar activities may lead to a fountain flow and mass may be accreted from outside (van Woerden et al., 2004).”
The Magellanic Stream, High-Velocity Clouds, and the Sculptor Group (2002, background): “Quilis & Moore (2001) find head-tail features are created in HVCs with typical lifetimes of ∼ 1 Gyr as long as the Galactic wind density is higher than 10−4 cm−3.”
The Progenitors of Dwarf Spheroidal Galaxies (2002, methodology): “The present-day mean density of the IGM beyond galaxy halos in the Local Group is thought to be nH ≤ 10 −5 cm−3, which is too low to remove H i even from dIrr/dSph dwarfs (see Quilis & Moore 2001), unless peculiar velocities are very high.”
Distances to Galactic High-Velocity Clouds. I. Cohen Stream, Complex GCP, Cloud g1 (2007, methodology): “As discussed by Wakker (2001), a safety factor needs to be taken into account for such a comparison, since we do not precisely know the H I column density (see discussion of Col.”
HIPASS High-Velocity Clouds: Properties of the Compact and Extended Populations (2001, background): “Quilis & Moore (2001) find that head-tail features in HVCs (similar to the :HVC pictured in Fig.”
The Origin of the Magellanic Stream and Its Leading Arm (2007, result): “We specifically compare our figure to Figure 1a of Wakker (2004).”
H i IN LOCAL GROUP DWARF GALAXIES AND STRIPPING BY THE GALACTIC HALO (2009, background): “Also, if there is independent evidence that a dwarf is being stripped at its current radius (e.g., head-tail structure; Quilis & Moore 2001), Figure 6 could be used to estimate a lower limit on the velocity of the satellite.”
Cold gas accretion in galaxies (2008, background): “The High-Velocity Clouds (HVCs) of neutral hydrogen in our galaxy [140] (see also recent review by Van Woerden et al. (2004) [137]) (Fig.7, top panel) have been considered since their discovery as possible direct evidence for infalling gas.”
Highly Ionized High-Velocity Gas in the Vicinity of the Galaxy (2002, background): “2 in Quilis & Moore 2001).”
Chemical evolution with radial mixing (2008, background): “Moreover, the handful of high-velocity clouds for which metallicities have been measured have heavy-element abundances of the order of a tenth solar (van Woerden & Wakker 2004).”
The gravitational and hydrodynamical interaction between the Large Magellanic Cloud and the Galaxy (2004, background): “As previously noticed by several authors (Quilis, Moore & Bower 2000; Quilis & Moore 2001; Schulz & Struck 2001), a bow shock forms in front of the disc, increasing the local intracluster medium (ICM) temperature from 106 to 2.5 × 106 K.”