Simulations of the Magellanic Stream in a First Infall Scenario

Besla, Gurtina; Kallivayalil, Nitya; Hernquist, Lars; Marel, Roeland P. van der; Cox, Thomas J.; Kereš, Dušan

doi:10.1088/2041-8205/721/2/l97

Cited by 251 publications

(314 citation statements)

References 48 publications

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“…Diaz & Bekki (2011) present a new tidal model in which, for the first time, structures resemble a clear bifurcation of the LA. Concerning LA4, we would like to note that the existence of this feature was predicted by Besla et al (2010), but their simulations fail to recover LA1. Hydrodynamic processes such as ram pressure are needed to shape the Magellanic Stream.…”

Section: Discussionmentioning

confidence: 90%

The four leading arms of the Magellanic Cloud system

Venzmer¹,

Kerp²,

Kalberla³

2012

A&A

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Context. The Magellanic Cloud system (MCS) interacts via tidal and drag forces with the Milky Way galaxy. Aims. Using the Parkes Galactic All-Sky Survey (GASS) of atomic hydrogen we explore the role of drag on the evolution of the so-called Leading Arm (LA).Methods. We present a new image recognition algorithm that allows us to differentiate features within a 3D data cube (longitude, latitude, radial velocity) and to parameterize individual coherent structures. We compiled an Hi object catalog of LA objects within an area of 70 • × 85 • (1.6 sr) of the LA region. This catalog comprises information of location, column density, line width, shape and asymmetries of the individual LA objects above the 4-σ threshold of ΔT b 200 mK.Results. We present evidence of a fourth arm segment (LA4). For all LA objects we find an inverse correlation of velocities v GSR in Galactic Standard of Rest frame with Magellanic longitude. High-mass objects tend to have higher radial velocities than low-mass ones. About 1/4 of all LA objects can be characterized as head-tail (HT) structures. Conclusions. Using image recognition with objective criteria, it is feasible to isolate most of LA emission from the diffuse Milky Way Hi gas. Some blended gas components (we estimate 5%) escape detection, but we find a total gas content of the LA that is about 50% higher than previously assumed. These methods allow the deceleration of the LA clouds to be traced towards the Milky Way disk by drag forces. The derived velocity gradient strongly supports the assumption that the whole LA originates entirely in the Large Magellanic Cloud (LMC). LA4 is observed opposite to LA1, and we propose that both arms are related, spanning about 52 kpc in space. HT structures trace drag forces even at tens of kpc altitudes above the Milky Way disk.

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Section: Discussionmentioning

confidence: 90%

The four leading arms of the Magellanic Cloud system

Venzmer¹,

Kerp²,

Kalberla³

2012

A&A

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“…This differs markedly from the canonical picture in which the Clouds travel on a quasi-periodic orbit about the MW (with a period of ∼2 Gyr). Without a short-period orbit about the MW, the origin of the Magellanic Stream, a young (1-2 Gyr old) coherent stream of H I gas that trails the Clouds and spans 150 • across the sky, can no longer be attributed to stripping by MW tides and/or ram pressure stripping by MW halo gas (taken from Besla et al 2010). In addition, the episodes of star-formation found in the LMC have been traditionally attributed to its repeated interaction with the MW and the SMC.…”

Section: Discussionmentioning

confidence: 99%

The recent star-formation history of the Large and Small Magellanic Clouds

Indu

Subramaniam

2011

A&A

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Aims. Recent interactions between the Large and the Small Magellanic Clouds (LMC and SMC) and the Milky Way can be understood by studying their recent star formation history. This study aims to detect any directional or propagating star formation in the last 500 Myr. Methods. We traced the age of the last star-formation event (LSFE) in the inner Large and Small Magellanic Cloud (L&SMC) using the photometric data in V and I passbands from the Optical Gravitational Lensing Experiment (OGLE-III) and the Magellanic Cloud Photometric Survey (MCPS). The LSFE is estimated from the main sequence turn-off point in the color-magnitude diagram (CMD) of a subregion. After correcting for extinction, the turn-off magnitude is converted to age, which represents the LSFE in a region.Results. The spatial distribution of the age of the LSFE shows that the star-formation has shrunk to within the central regions in the last 100 Myr in both the galaxies. The location as well as age of LSFE is found to correlate well with those of the star cluster in both the Clouds. The SMC map shows two separate concentrations of young star-formation, one near the center and the other near the wing. We detect peaks of star-formation at 0-10 Myr and 90-100 Myr in the LMC, and 0-10 Myr and 50-60 Myr in the SMC. The quenching of star-formation in the LMC is found to be asymmetric with respect to the optical center such that most of the young star forming regions are located to the north and east. On deprojecting the data onto the LMC plane, the recent star-formation appears to be stretched in the northeast direction and the HI gas is found to be distributed preferentially in the north. We found that the centroid is shifted to the north during the time interval 200-40 Myr, whereas it is found to have shifted to the northeast in the last 40 Myr. In the SMC, we detect a shift in the centroid of the population younger than 500 Myr and as young as 40 Myr in the direction of the LMC. Conclusions. We propose that the HI gas in the LMC has been pulled to the north of the LMC in the last 200 Myr because of the gravitational attraction of our Galaxy at the time of perigalactic passage. The shifted HI gas was preferentially compressed in the north during the time interval 200-40 Myr and in the northeast in the last 40 Myr, owing to the motion of the LMC in the Galactic halo. The recent star-formation in the SMC is due to the combined gravitational effect of the LMC and the perigalactic passage.

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“…A tidal origin of the Stream from the interaction between the LMC and the Milky Way (MW) has been ruled out by new proper motion measurements (Kallivayalil et al 2006a,b). Alternative explanations are: ram pressure (Mastropietro et al 2005) and tidal origin from the interaction between the LMC and the SMC (Besla et al 2010).…”

Section: Introductionmentioning

confidence: 99%

The VMC survey

Cioni

Clementini

Girardi

et al. 2011

A&A

311

304

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Context. The new VISual and Infrared Telescope for Astronomy (VISTA) has started operations. Over its first five years it will be collecting data for six public surveys, one of which is the near-infrared Y JK s VISTA survey of the Magellanic Clouds system (VMC). This survey comprises the Large Magellanic Cloud (LMC), the Small Magellanic Cloud, the Magellanic Bridge connecting the two galaxies and two fields in the Magellanic Stream. Aims. This paper provides an overview of the VMC survey strategy and presents first science results. The main goals of the VMC survey are the determination of the spatially-resolved star-formation history and the three-dimensional structure of the Magellanic system. The VMC survey is therefore designed to reach stars as faint as the oldest main sequence turn-off point and to constrain the mean magnitude of pulsating variables such as RR Lyrae stars and Cepheids. This paper focuses on observations of VMC fields in the LMC obtained between November 2009 and March 2010. These observations correspond to a completeness of 7% of the planned LMC fields. Methods. The VMC data are comprised of multi-epoch observations which are executed following specific time constraints. The data were reduced using the VISTA Data Flow System pipeline with source catalogues, including astrometric and photometric corrections, produced and made available via the VISTA Science Archive. The VMC data will be released to the astronomical community following the European Southern Observatory's Public Survey policy. The analysis of the data shows that the sensitivity in each wave band agrees with expectations. Uncertainties and completeness of the data are also derived. Results. The first science results, aimed at assessing the scientific quality of the VMC data, include an overview of the distribution of stars in colour-magnitude and colour-colour diagrams, the detection of planetary nebulae and stellar clusters, and the K s band light-curves of variable stars. Conclusions. The VMC survey represents a tremendous improvement, in spatial resolution and sensitivity, on previous panoramic observations of the Magellanic system in the near-infrared, providing a powerful complement to deep observations at other wavelengths.

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Simulations of the Magellanic Stream in a First Infall Scenario

Cited by 251 publications

References 48 publications

The four leading arms of the Magellanic Cloud system

The four leading arms of the Magellanic Cloud system

The recent star-formation history of the Large and Small Magellanic Clouds

The VMC survey

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