Gas-Rich Dwarf Spheroidals

By L. Blitz, T. Robishaw. 2000

139 citations recorded by the source corpus.

We present evidence that 10 of the 21 dwarf spheroidal galaxies (dSph and dSph/dIrr) in the Local Group are associated with large reservoirs of atomic gas, reservoirs that are, in some cases, larger than the stellar mass. The gas is sometimes found at a large distance (~10 kpc) from the center of a galaxy and is not necessarily centered on it. Similarly large quantities of ionized gas could be hidden in these systems as well. The properties of some of the gas reservoirs are similar to the median properties of the high-velocity clouds (HVCs); two of the H I reservoirs are cataloged HVCs. The association of the H I with the dwarf spheroidals might thus provide a link between the HVCs and stars. We show that the H I content of the Local Group dSphs and dIrrs exhibits a sharp decline if the galaxy is within 250 kpc of either the Milky Way or M31. This can be explained if both galaxies have a sufficiently massive X-ray-emitting halo that produces ram-pressure stripping if a dwarf ventures too close to either giant spiral. We also investigate tidal stripping of the dwarf galaxies and find that although it may play a role, it cannot explain the apparent total absence of neutral gas in most dSph galaxies at distances less than 250 kpc. For the derived mean density of the hot gas, n° = 2.5 × 10-5 cm-3, ram-pressure stripping is found to be more than an order of magnitude more effective in removing the gas from the dSph galaxies. The hot halo, with an inferred mass of 1 × 1010 M☉, may represent a reservoir of ~103 destroyed dwarf systems—either HVCs or true dwarf galaxies similar to those we observe now.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/ded5462e81125ffb4d147de2da4fc6b117f14f95

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

In Statistical and Nonlinear Physics

Citations in the corpus

Where Are the High-Velocity Clouds? (2001, background): “Blitz & Robishaw (2000) derive a halo gas density that is a factor of 2 lower than this at a distance of 200 kpc by applying ram pressure stripping to the halo dwarf spheroidals.”
The Progenitors of Dwarf Spheroidal Galaxies (2002, background): “Blitz & Robishaw (2000) suggest that ram pressure stripping is the most probable cause for the removal of the gas, if the nearby H i clouds were indeed once part of the dSphs.”
DO HOT HALOS AROUND GALAXIES CONTAIN THE MISSING BARYONS? (2010, background): “Blitz & Robishaw (2000) measure H i mass for the dwarf spheroidal galaxies in the Local Group, and use these masses to place upper limits on the amount of ram-pressure stripping that these galaxies could have experiences.”
The Origin of C IV Absorption Systems at Redshifts z < 1: Discovery of Extended C IV Envelopes around Galaxies (2001, background): “In addition, H I 21 cm analysis of local dwarf spheroidals suggests that the presence of satellite galaxies may contribute to extended gas in galactic halos (Blitz & Robishaw 2000).”
Tracing Galaxy Formation with Stellar Halos. I. Methods (2005, background): “Physically, this could result from gas loss via ram-pressure stripping from the background hot gas halo (Lin & Faber 1983; Moore & Davis 1994; Blitz & Robishaw 2000; Maller & Bullock 2004; Mayer et al. 2005).”
Gaseous Galaxy Halos (2012, background): “2) Satellite galaxies are stripped of their gas out to large radii, most likely as they move through this diffuse hot halo medium (Grcevich & Putman, 2009; Blitz & Robishaw, 2000).”
THE STRUCTURE OF THE MILKY WAY'S HOT GAS HALO (2013, methodology): “Blitz & Robishaw (2000) found that dwarf spheroidal galaxies orbiting the Milky Way will effectively lose their cold gas due to ram-pressure stripping for an ambient halo with density of n 2.4 × 10−5 cm−3 out to the virial radius of the Milky Way.”
THE OBSERVED PROPERTIES OF DWARF GALAXIES IN AND AROUND THE LOCAL GROUP (2012, unknown): “N/A N/A N/A N/A N/A . . . (35) (34) (5) Not associated with H i detection in Blitz & Robishaw (2000) Andromeda X 0.096 3.9 1.2 . . . . . .”
The Metamorphosis of Tidally Stirred Dwarf Galaxies (2001, background): “Among mechanisms related to the local environment, the ram pressure stripping scenario has been invoked frequently for the dwarfs in the Local Group (Einasto et al. 1974 ; Faber & Lin 1983 ; van den Bergh 1999 ; Blitz & Robishaw 2000).”
Highly Ionized High-Velocity Gas in the Vicinity of the Galaxy (2002, background): “…1, 2003 HIGHLY IONIZED HIGH-VELOCITY GAS 203 postulated a hot, low-density corona to provide ram pressure stripping of some of theMagellanic Cloud gas and to explain the absence of gas in globular clusters and nearby dwarf spheroidal companions to the Milky Way (see also Blitz & Robishaw 2000).”
Abundance Patterns in the Draco, Sextans, and Ursa Minor Dwarf Spheroidal Galaxies (2000, background): “These three galaxies contain little or no gas (Blitz & Robishaw 2000) and are comprised predominantly of old stars, although Mateo, Fischer & Krzeminski (1995 report the presence of a modest intermediate-age population in Sextans.”
Farthest Neighbor: The Distant Milky Way Satellite Eridanus II (2016, background): “250 kpc) and the more distant gas-rich star-forming dwarfs (Einasto et al. 1974; Blitz & Robishaw 2000; Grcevich & Putman 2009; Spekkens et al. 2014).”
The gravitational and hydrodynamical interaction between the Large Magellanic Cloud and the Galaxy (2004, methodology): “At larger distances from the Galactic Centre, constraints on the halo density are poor, although Blitz & Robishaw (2000) derive a value of 2.5 × 10−5 cm−3 at a distance of 200 kpc by applying ram-pressure stripping to dwarf spheroidal galaxies within the Galactic halo.”
The Search for the Missing Baryons at Low Redshift (2007, background): “At greater radii, there is a useful density estimate from Blitz & Robishaw (2000) who point out that the nearer dwarf galaxies are devoid of cold gas while the more distant ones sometimes have HI.”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, background): “F or p er so na l u se o nl y. Table 8 Total mass estimates for the Galaxy Reference Method M200 M100 Mrkpc R200 R100 r Wilkinson & Evans (1999) Distribution function based 1.67 2.39 0.54 243.9 346.0 50 Sakamoto et al. (2003) Mixed halo object kinematics 1.67 2.39 0.54 243.9 346.0 50 Dehnen et al. (”
Constraints on the distribution and energetics of fast radio bursts using cosmological hydrodynamic simulations (2014, methodology): “…density distributions representative of the Galactic halo, overplotted with observational data and constrain s covering the entire virial radius, as presented by Miller & Bregman (2013), Grcevich & Putman (2009), Blitz & Robishaw (2000), Bregman & Lloyd-Davies (2007) and Gupta et al. (2012).”
ELVIS: Exploring the Local Volume in Simulations (2013, background): “…future resolved-star surveys promise to discover faint optical galaxies throughout the Local Volume, HI surveys offer a complementary approach for the discovery of dwarfs in the near-field (Blitz et al. 1999; Blitz & Robishaw 2000; Sternberg et al. 2002; Adams et al. 2013; Faerman et al. 2013).”
Simultaneous ram pressure and tidal stripping; how dwarf spheroidals lost their gas (2005, background): “Ram pressure stripping of gas from dIrr-like progenitors caused by a hot diffuse gaseous corona surrounding the Milky Way has been proposed as a way to explain the low gas contents of dSphs together with the similar stellar light distributions of the two types of dwarfs (Einasto et al. 1974; Faber &”