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Related papers: The Smith Cloud: HI associated with the Sgr dwarf?

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New 21cm HI observations made with the Green Bank Telescope show that the high-velocity cloud known as Smith's Cloud has a striking cometary appearance and many indications of interaction with the Galactic ISM. The velocities of interaction…

Astrophysics · Physics 2009-11-13 Felix J. Lockman , Robert A. Benjamin , A. J. Heroux , Glen I. Langston

We present Wisconsin H-Alpha Mapper observations of ionized gas in the Smith Cloud, a high velocity cloud which Lockman et al. have recently suggested is interacting with the Galactic disk. Our H-alpha map shows the brightest H-alpha…

Astrophysics of Galaxies · Physics 2009-09-17 Alex S. Hill , L. Matthew Haffner , Ronald J. Reynolds

The Smith Cloud is a gaseous high-velocity cloud (HVC) in an advanced state of accretion, only 2.9 kpc below the Galactic plane and due to impact the disk in 27 Myr. It is unique among HVCs in having a known distance (12.4+/-1.3 kpc) and a…

We report the first detection of magnetic fields associated with the Smith High Velocity Cloud. We use a catalog of Faraday rotation measures towards extragalactic radio sources behind the Smith Cloud, new HI observations from the Green…

Astrophysics of Galaxies · Physics 2013-11-05 Alex S. Hill , S. A. Mao , Robert A. Benjamin , Felix J. Lockman , Naomi M. McClure-Griffiths

We present findings of 3D filamentary structures in the Smith Cloud, a high-velocity cloud (HVC) located at $l=38^{\circ}$, $b=-13^{\circ}$. We use data from the Galactic Arecibo L-Band Feed Array \ion{H}{i} (GALFA-\ion{H}{i}) along with…

Astrophysics of Galaxies · Physics 2025-05-06 Colin Holm-Hansen , M. E. Putman , D. A. Kim

We have used the Green Bank Telescope (GBT) to search for the OH molecule at several locations in the Smith Cloud, one of the most prominent of the high-velocity clouds that surround the Milky Way. Five positions with a high HI column…

Astrophysics of Galaxies · Physics 2024-03-14 Anthony H. Minter , Felix J. Lockman , S. A. Balashev , H. Alyson Ford

We present WHAM observations of Halpha, [N II], and [S II] in the Smith Cloud. A map of Halpha emission from the cloud shows ionized gas coincident with the brightest H I emission, but nearly-as-bright Halpha in some regions with faint H I.…

Astrophysics of Galaxies · Physics 2012-09-26 Alex S. Hill , L. Matthew Haffner , Ronald J. Reynolds

High velocity clouds supply the Milky Way with gas that sustains star formation over cosmic timescales. Precise distance measurements are therefore essential to quantify their mass inflow rates and gauge their exact contribution to the…

We have identified a new structure in the Milky Way: a leading component of the Smith high velocity cloud that is now crossing the Galactic plane near longitude 25 degrees. Using new 21cm HI data from the Green Bank Telescope (GBT) we…

Astrophysics of Galaxies · Physics 2023-02-01 Felix J. Lockman , Robert A. Benjamin , Nicolas Pichette , Christopher Thibodeau

The Smith Cloud is a high-velocity cloud (HVC) on its final approach to the Milky Way that shows evidence of interaction with the Galaxy's disk. We investigate the metallicity and gas-phase chemical depletion patterns in this HVC using UV…

Motivated by the idea that a subset of HVCs trace dark matter substructure in the Local Group, we search for signs of star formation in the Smith Cloud, a nearby ~2x10^6 Msun HVC currently falling into the Milky Way. Using GALEX NUV and…

Astrophysics of Galaxies · Physics 2015-06-23 David V. Stark , Ashley D. Baker , Sheila J. Kannappan

We report results from a survey of high velocity clouds and the Magellanic Stream for faint, diffuse optical recombination emission lines. We detect H-alpha emission with surface brightness from 41 to 1680 milli-Rayleighs (mR) from HVCs,…

Astrophysics · Physics 2007-05-23 Benjamin J. Weiner , Stuart N. Vogel , T. B. Williams

We present deep Halpha spectroscopy towards several high-velocity clouds (HVCs) which vary in structure from compact (CHVCs) to the Magellanic Stream. The clouds range from being bright (~640 mR) to having upper limits on the order of 30 to…

Astrophysics · Physics 2009-11-10 M. E. Putman , J. Bland-Hawthorn , S. Veilleux , B. K. Gibson , K. C. Freeman , P. R. Maloney

The origin and survival of the Smith high-velocity HI cloud has so far defied explanation. This object has several remarkable properties: (i) its prograde orbit is ~100 km/s faster than the underlying Galactic rotation; (ii) its total gas…

Astrophysics of Galaxies · Physics 2017-12-20 Thor Tepper-Garcia , Joss Bland-Hawthorn

Using data from the Southern Galactic Plane Survey (SGPS) we analyze an HI self-absorption cloud centered on l = 318.0 deg, b = -0.5 deg, and velocity, v = -1.1 km/s. The cloud was observed with the Australia Telescope Compact Array (ATCA)…

Astrophysics · Physics 2009-11-10 D. W. Kavars , J. M. Dickey , N. M. McClure-Griffiths , B. M. Gaensler , A. J. Green

Optical emission lines have now been detected from about 20 high velocity clouds. These emission lines -- primarily H-alpha, secondarily [N II] and [S II] -- are very faint and diffuse, spread over the surfaces of the clouds. We compile…

Astrophysics · Physics 2007-05-23 Benjamin J. Weiner , Stuart N. Vogel , T. B. Williams

The Spitzer Space Telescope (formerly SIRTF) extragalactic First-Look Survey covered about 5 square degrees centered on J2000 17:18 +59:30 in order to characterize the infrared sky with high sensitivity. We used the 100-m Green Bank…

Astrophysics · Physics 2009-11-10 Felix J. Lockman , J. J. Condon

We present a study of diffuse extended ionised gas toward three clouds located in the Galactic Centre (GC). One line of sight (LOS) is toward the 20 km s$^{-1}$ cloud (LOS$-$0.11) in the Sgr A region, another LOS is toward the 50 km…

We have mapped two molecular clouds at (l, b) = (3.2 degrees, + 0.3 degrees) and (l, b) = (5.4 degrees, -0.5 degrees) in 21-cm line and continuum emission. These clouds show unusually large velocity dispersions of more than 100 km/s (FWHM)…

Astrophysics · Physics 2015-06-24 Harald Riffert , Pawan Kumar , W. K. Huchtmeier

The Wisconsin H-Alpha Mapper (WHAM) Northern Sky Survey is revealing that many intermediate-velocity (|v_LSR| <= 100 km/s) neutral clouds and complexes have an associated ionized component. We present the first map of the H-Alpha emission…

Astrophysics · Physics 2009-11-06 L. M. Haffner , R. J. Reynolds , S. L. Tufte
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