scholarly journals Cold H i ejected into the Magellanic Stream

2020 ◽  
Vol 496 (1) ◽  
pp. 913-920
Author(s):  
J Dempsey ◽  
N M McClure-Griffiths ◽  
K Jameson ◽  
F Buckland-Willis
Keyword(s):  
Absorption Line ◽  
Direct Detection ◽  
Magellanic Clouds ◽  
Spin Excitation ◽  
Excitation Temperature ◽  
Small Magellanic Cloud ◽  
Galactic Source ◽  
Magellanic Stream ◽  
Compact Array ◽  
Cold Gas

ABSTRACT We report the direct detection of cold H i gas in a cloud ejected from the Small Magellanic Cloud (SMC) towards the Magellanic Stream. The cloud is part of a fragmented shell of H i gas on the outskirts of the SMC. This is the second direct detection of cold H i associated with the Magellanic Stream using absorption. The cold gas was detected using 21-cm H i absorption-line observations with the Australia Telescope Compact Array (ATCA) towards the extra-galactic source PMN J0029−7228. We find a spin (excitation) temperature for the gas of 68 ± 20 K. We suggest that breaking super shells from the Magellanic Clouds may be a source of cold gas to supply the rest of the Magellanic Stream.

scholarly journals The interstellar medium of the Magellanic Clouds from absorption lines

1991 ◽  
Vol 148 ◽  
pp. 401-406 ◽  
Author(s):  
Klaas S. De Boer
Keyword(s):  
Interstellar Medium ◽  
Absorption Line ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Absorption Lines ◽  
Small Magellanic Cloud ◽  
General Aspects

General aspects of ISM studies using absorption line studies are given and available data are reviewed. Topics are: galactic foreground gas, individual fields in the Magellanic Clouds (MCs) and MC coronae. Overall investigations are discussed. It is demonstrated that the metals in the gas of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) are a factor of 3 and 10, respectively, in abundance below solar levels. The depletion pattern in the LMC is similar to that of the Milky Way.

scholarly journals N-Body Simulations of the Magellanic System Including Gas Dynamics and Star Formation

1999 ◽  
Vol 186 ◽  
pp. 60-60
Author(s):  
A.M. Yoshizawa ◽  
M. Noguchi
Keyword(s):  
Star Formation ◽  
Gas Dynamics ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
Tidal Distortion ◽  
Formation And Evolution ◽  
Magellanic Stream ◽  
Magellanic System

The system of the Magellanic Clouds is considered to be dynamically interacting among themselves and with our Galaxy. This interaction is thought to be the cause of many complicated features seen in the Magellanic Clouds and the Magellanic Stream (see Westerlund 1990, A&AR, 2, 27). In order to better understand the formation and evolution of the Magellanic System, we carry out realistic N-body simulations of the tidal distortion of the Small Magellanic Cloud (SMC) due to our Galaxy and the Large Magellanic Cloud (LMC).

scholarly journals The Magellanic Stream

1974 ◽  
Vol 60 ◽  
pp. 617-624
Author(s):  
D. S. Mathewson ◽  
M. N. Cleary ◽  
J. D. Murray
Keyword(s):  
Galactic Plane ◽  
Gravitational Interaction ◽  
Great Circle ◽  
Magellanic Clouds ◽  
The Other ◽  
Small Magellanic Cloud ◽  
Velocity Range ◽  
Sky Survey ◽  
The Galaxy ◽  
Magellanic Stream

A southern sky survey of Hiin the velocity range − 340 km s−1 to + 380 km s−1 has shown that a long filament of H iextends from the Small Magellanic Cloud (SMC) region down to the South Galactic Pole and connects with the long Hifilament discovered recently by Wannier and Wrixon (1972) and van Kuilenberg (1972). There is also some evidence that this continues on the other side of the Magellanic Clouds and crosses the galactic plane at l = 306°. This filament, which follows very closely a great circle over its entire 180° arc across the sky, is given the name ‘The Magellanic Stream’. It may have been produced by gravitational interaction between the SMC and the Galaxy during a close passage (20 kpc) of the SMC some 5 × 108 yr ago, although it is impossible to account for the observed radial velocities along the Stream unless some force other than gravity is invoked to act on the Stream as well.

scholarly journals The Magellanic Stream

1974 ◽  
Vol 58 ◽  
pp. 367-374 ◽  
Author(s):  
D. S. Mathewson ◽  
M. N. Cleary ◽  
J. D. Murray
Keyword(s):  
Galactic Plane ◽  
Gravitational Interaction ◽  
Great Circle ◽  
Magellanic Clouds ◽  
The Other ◽  
Small Magellanic Cloud ◽  
Velocity Range ◽  
Sky Survey ◽  
The Galaxy ◽  
Magellanic Stream

A southern sky survey of H I in the velocity range — 340 km s−1 to +380 km s−1 has shown that a long filament of H I extends from the Small Magellanic Cloud (SMC) region down to the South Galactic Pole and connects with the long H I filament discovered recently by Wannier and Wrixon (1972) and van Kuilenburg (1972). There is also some evidence that the feature continues on the other side of the Magellanic Clouds and crosses the galactic plane at l = 306°. The whole filament, which follows very closely a great circle over its entire 180° length, is given the name ‘The Magellanic Stream’. It may have been produced by gravitational interaction between the SMC and the Galaxy during a close passage (20 kpc) of the SMC some 5 × 108 yr ago although it is impossible to account for the observed radial velocities along the Stream unless some force other than gravity is invoked to act on the Stream as well.

scholarly journals The Magellanic Stream and its Related Problems

1984 ◽  
Vol 108 ◽  
pp. 115-123 ◽  
Author(s):  
M. Fujimoto ◽  
T. Murai
Keyword(s):  
Radial Velocity ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Optical Observations ◽  
Dark Halo ◽  
Small Magellanic Cloud ◽  
Characteristic Structure ◽  
Tidal Model ◽  
Space Orientation ◽  
Magellanic Stream

A brief survey is made of recent 21-cm and optical observations of the Magellanic Stream(MS). The space orientation of the Magellanic Clouds is touched upon in relation to modelling the MS. After summarizing a variety of models for the MS, we show that if our Galaxy is massive with a huge dark halo, a tidal model is most suitable for reproducing its characteristic structure and high-negative radial velocity. Past orbits of the Large and the Small Magellanic Cloud (LMC and SMC) are determined uniquely for the last 2×109 yr, if we postulate that the LMC and SMC are bound together for 1010 yr: Highly-noncircular motion of the SMC around the LMC could give a clue to understand some peculiar features associated with the Magellanic Clouds.

scholarly journals An overview of the structure and kinematics of the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 15-23 ◽  
Author(s):  
B. E. Westerlund
Keyword(s):  
Star Formation ◽  
Observational Data ◽  
Spiral Structure ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Line Of Sight ◽  
Small Magellanic Cloud ◽  
Complex Velocity ◽  
The Past

A vast amount of observational data concerning the structure and kinematics of the Magellanic Clouds is now available. Many basic quantities (e.g. distances and geometry) are, however, not yet sufficiently well determined. Interactions between the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC) and our Galaxy have dominated the evolution of the Clouds, causing bursts of star formation which, together with stochastic self-propagating star formation, produced the observed structures. In the youngest generation in the LMC it is seen as an intricate pattern imitating a fragmented spiral structure. In the SMC much of the fragmentation is along the line of sight complicating the reconstruction of its history. The violent events in the past are also recognizable in complex velocity patterns which make the analysis of the kinematics of the Clouds difficult.

scholarly journals Probing the cool ISM in galaxies via 21 cm H i absorption

2012 ◽  
Vol 8 (S292) ◽  
pp. 188-188
Author(s):  
J. R. Allison ◽  
E. M. Sadler ◽  
S. J. Curran ◽  
S. N. Reeves
Keyword(s):  
Spectral Line ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Host Galaxies ◽  
The Galaxy ◽  
Early Type Galaxy ◽  
Finding Method ◽  
Compact Array ◽  
Cold Gas

AbstractRecent targeted studies of associated H i absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated H i absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).

scholarly journals Comparison of Discrete Sources in Radio and Hα Surveys of the Magellanic Clouds and the Potential for the New Hα Survey

1998 ◽  
Vol 15 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Miroslav D. Filipović ◽  
Paul A. Jones ◽  
Graeme L. White ◽  
Raymond F. Haynes
Keyword(s):  
Supernova Remnants ◽  
Hii Regions ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud

AbstractWe present a comparison between the latest Parkes radio surveys (Filipović et al. 1995, 1996, 1997) and Hα surveys of the Magellanic Clouds (Kennicutt & Hodge 1986). We have found 180 discrete sources in common for the Large Magellanic Cloud (LMC) and 40 in the field of the Small Magellanic Cloud (SMC). Most of these sources (95%) are HII regions and supernova remnants (SNRs). A comparison of the radio and Hα flux densities shows a very good correlation and we note that many of the Magellanic Clouds SNRs are embedded in HII regions.

scholarly journals How to Model the Chemical Evolution of Galaxies

1993 ◽  
Vol 155 ◽  
pp. 557-566
Author(s):  
Joachim Köppen
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Time Scale ◽  
Life Time ◽  
Magellanic Clouds ◽  
Formation Time ◽  
List Type ◽  
The Galaxy ◽  
H Ii Region ◽  
Magellanic Stream

For a first interpretation of the comparison of observational data, the crude “Simple Model” of chemical evolution is quite useful. Since it has well been described in the literature (e.g. Pagel and Patchett 1975, Tinsley 1980), let us here just review the assumptions and whether they are satisfied: 1.The galaxy is a closed system, with no exchange of matter with its surroundings: For the solar neighbourhood this probably is not true (the infamous Gdwarf-“problem”, Pagel 1989b). For the Magellanic Clouds this is most certainly wrong, because of the presence of the Inter-Cloud Region and the Magellanic Stream, and evidence for interaction with each other and the Galaxy as well (cf. e.g. Westerlund 1990).2.It initially consists entirely of gas (without loss of generality of primordial composition): This is good approximation also for models with gas infall, as long as the infall occurs with a time scale shorter than the star formation time scale.3.The metal production of the average stellar generation (the yield y) is constant with time: Initially, it is reasonable to make this assumption. For tables of the oxygen yield see Koppen and Arimoto (1991).4.The metal rich gas ejected by the stars is completely mixed with the ambient gas. To neglect the finite stellar life times (“instantaneous recycling approximation”) is appropriate for elements synthesized in stars whose life time is much shorter than the star formation time scale, such as oxygen, neon, sulphur, and argon.5.The gas is well mixed at all times: We don't know. The dispersion of H II region abundances may give an indication. In the Magellanic Clouds Dufour (1984) finds quite a low value (±0.08 dex for oyxgen).

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