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Related papers: HI shells in the outer Milky Way

200 papers

Globular Clusters (GCs) displaying extended structures are becoming increasingly ubiquitous in the Milky Way (MW). Despite their low surface brightness, which makes disentangling the true structure from the MW overwhelmingly difficult, the…

Astrophysics of Galaxies · Physics 2025-07-09 Pete B. Kuzma , Miho N. Ishigaki , Takanobu Kirihara , Itsuki Ogami

We use A-type stars selected from Sloan Digital Sky Survey data release 9 photometry to measure the outer slope of the Milky Way stellar halo density profile beyond 50 kpc. A likelihood-based analysis is employed that models the ugr…

Astrophysics of Galaxies · Physics 2015-06-19 Alis J. Deason , Vasily Belokurov , Sergey E. Koposov , Connie M. Rockosi

In this second paper on the investigation of extraplanar diffuse ionized gas in nearby edge-on spiral galaxies we present the actual results of the individual galaxies of our H-alpha imaging survey. A grand total of 74 galaxies have been…

Astrophysics · Physics 2009-11-07 Joern Rossa , Ralf-Juergen Dettmar

A number of very small isolated HII regions have been discovered at projected distances up to 30 kpc from their nearest galaxy. These HII regions appear as tiny emission line objects in narrow band images obtained by the NOAO Survey for…

Elemental abundance patterns in the Galactic disk constrain theories of the formation and evolution of the Milky Way. HII region abundances are the result of billions of years of chemical evolution. We made radio recombination line and…

Astrophysics of Galaxies · Physics 2015-05-18 Dana S. Balser , Trey V. Wenger , L. D. Anderson , T. M. Bania

We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…

This study presents a tomographic survey of a subset of the outer halo (10-40 kpc) drawn from the Sloan Digital Sky Survey Data Release 6. Halo substructure on spatial scales of $>3$ degrees is revealed as an excess in the local density of…

Astrophysics of Galaxies · Physics 2015-05-14 Stefan C. Keller

We present evidence for a ring of stars in the plane of the Milky Way, extending at least from l = 180 deg to l = 227 deg with turnoff magnitude $g \sim 19.5$; the ring could encircle the Galaxy. We infer that the low Galactic latitude…

We provide a set of numerical N-body simulations for studying the formation of the outer Milky Ways's stellar halo through accretion events. After simulating minor mergers of prograde and retrograde orbiting satellite halo with a Dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Giuseppe Murante , Eva Poglio , Anna Curir , Alvaro Villalobos

An earlier analysis of the Milky Way Star Cluster (MWSC) catalogue revealed an apparent lack of old (> 1 Gyr) open clusters in the solar neighbourhood (< 1 kpc). To fill this gap we undertook a search for hitherto unknown star clusters,…

Astrophysics of Galaxies · Physics 2014-09-05 S. Schmeja , N. V. Kharchenko , A. E. Piskunov , S. Röser , E. Schilbach , D. Froebrich , R. -D. Scholz

Fast radio bursts offer the opportunity to place new constraints on the mass and density profile of hot and ionized gas in galactic haloes. We test here the X-ray emission and dispersion measure predicted by different gas profiles for the…

Astrophysics of Galaxies · Physics 2020-06-03 Laura C. Keating , Ue-Li Pen

Little is known about the portion of the Milky Way lying beyond the Galactic center at distances of more than 9 kilo-parsec from the Sun. These regions are opaque at optical wavelengths due to absorption by interstellar dust, and distances…

Astrophysics of Galaxies · Physics 2017-10-19 Alberto Sanna , Mark J. Reid , Thomas M. Dame , Karl M. Menten , Andreas Brunthaler

A complete map of the 3D distribution of molecular (CO) gas was constructed using a realistic dynamical model of the gas flow in the barred potential of the Milky Way. The map shows two prominent spiral arms starting at the bar ends…

Astrophysics · Physics 2008-12-19 Peter Englmaier , Martin Pohl , Nicolai Bissantz

Aims: We show the existence of a small family of inner-galaxy dust lanes and dust lane standing shocks beyond the two major ones that were previously known to exist Methods: We analyze images of CO emission in the inner regions of the…

Astrophysics of Galaxies · Physics 2009-11-13 H. S. Liszt

During the initial data reduction of the Wisconsin H-Alpha Mapper (WHAM) H-Alpha Sky Survey, we have discovered several very long (~30--80 deg) filaments superimposed on the diffuse H-Alpha background. These features have no clear…

Astrophysics · Physics 2009-10-30 L. M. Haffner , R. J. Reynolds , S. L. Tufte

Aims: On the basis of the PPMXL star catalogue we performed a survey of star clusters in the second quadrant of the Milky Way. Methods: From the PPMXL catalogue of positions and proper motions we took the subset of stars with near-infrared…

Astrophysics of Galaxies · Physics 2015-06-05 N. V. Kharchenko , A. E. Piskunov , E. Schilbach , S. Röser , R. -D. Scholz

To estimate the parameters of the Galactic spiral structure - namely, the pitch angle i and the number of spiral arms,- data on Galactic masers with known trigonometric parallaxes were used. We applied the well-known method based on…

Astrophysics of Galaxies · Physics 2015-06-17 Vadim V. Bobylev , Anisa T. Bajkova

We analyse absorption characteristics and physical conditions of extraplanar intermediate- and high-velocity gas to study the distribution of the neutral and weakly ionised Milky Way halo gas and its relevance for the evolution of the Milky…

Astrophysics · Physics 2015-05-13 N. Ben Bekhti , P. Richter , T. Westmeier , M. T. Murphy

The light distribution in the inner few kiloparsecs of the Milky Way is recovered non-parametrically from a dust-corrected near-infrared COBE/DIRBE surface brightness map of the inner Galaxy. The best fits to the photometry are obtained…

Astrophysics · Physics 2015-06-24 James Binney , Ortwin Gerhard , David Spergel

The structure, extent, and mass of the Milky Way's (MW) dark matter (DM) halo are observationally challenging to determine due to our position within the Galaxy. To overcome this limitation, we study a combined sample of 127 MW analogs from…

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