Formation of a counter-rotating stellar population in the Large Magellanic Cloud: A Magellanic triplet system?

B. Armstrong, K. Bekki

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Abstract

The Large Magellanic Cloud is observed to have a counter-rotating stellar population in its disc, which has not been reproduced in previous simulations of the Magellanic system. We propose a new scenario in which the origin of this counter-rotating stellar population is the result of a minor retrograde merger with another dwarf galaxy more than 3 Gyr ago, and investigate this scenario using our hydrodynamical simulations. Our simulations show that such merging can result in a counter-rotating stellar component and a co-rotating gaseous component.We show that this counter-rotating population would not be radially concentrated, but found throughout the Large Magellanic Cloud. The thin disc of the Large Magellanic Cloud is thickened by the merging. We suggest that the Magellanic Clouds were originally a triplet system containing this companion galaxy.We then discuss previous observations of the Magellanic Clouds in the context of a triplet dwarf system, and discuss how such a merger could occur.

Original languageEnglish
Pages (from-to)L141-L145
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume480
Issue number1
DOIs
Publication statusPublished - 1 Jan 2018

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Magellanic clouds
counters
merger
simulation
dwarf galaxies
galaxies

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title = "Formation of a counter-rotating stellar population in the Large Magellanic Cloud: A Magellanic triplet system?",
abstract = "The Large Magellanic Cloud is observed to have a counter-rotating stellar population in its disc, which has not been reproduced in previous simulations of the Magellanic system. We propose a new scenario in which the origin of this counter-rotating stellar population is the result of a minor retrograde merger with another dwarf galaxy more than 3 Gyr ago, and investigate this scenario using our hydrodynamical simulations. Our simulations show that such merging can result in a counter-rotating stellar component and a co-rotating gaseous component.We show that this counter-rotating population would not be radially concentrated, but found throughout the Large Magellanic Cloud. The thin disc of the Large Magellanic Cloud is thickened by the merging. We suggest that the Magellanic Clouds were originally a triplet system containing this companion galaxy.We then discuss previous observations of the Magellanic Clouds in the context of a triplet dwarf system, and discuss how such a merger could occur.",
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TY - JOUR

T1 - Formation of a counter-rotating stellar population in the Large Magellanic Cloud

T2 - A Magellanic triplet system?

AU - Armstrong, B.

AU - Bekki, K.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - The Large Magellanic Cloud is observed to have a counter-rotating stellar population in its disc, which has not been reproduced in previous simulations of the Magellanic system. We propose a new scenario in which the origin of this counter-rotating stellar population is the result of a minor retrograde merger with another dwarf galaxy more than 3 Gyr ago, and investigate this scenario using our hydrodynamical simulations. Our simulations show that such merging can result in a counter-rotating stellar component and a co-rotating gaseous component.We show that this counter-rotating population would not be radially concentrated, but found throughout the Large Magellanic Cloud. The thin disc of the Large Magellanic Cloud is thickened by the merging. We suggest that the Magellanic Clouds were originally a triplet system containing this companion galaxy.We then discuss previous observations of the Magellanic Clouds in the context of a triplet dwarf system, and discuss how such a merger could occur.

AB - The Large Magellanic Cloud is observed to have a counter-rotating stellar population in its disc, which has not been reproduced in previous simulations of the Magellanic system. We propose a new scenario in which the origin of this counter-rotating stellar population is the result of a minor retrograde merger with another dwarf galaxy more than 3 Gyr ago, and investigate this scenario using our hydrodynamical simulations. Our simulations show that such merging can result in a counter-rotating stellar component and a co-rotating gaseous component.We show that this counter-rotating population would not be radially concentrated, but found throughout the Large Magellanic Cloud. The thin disc of the Large Magellanic Cloud is thickened by the merging. We suggest that the Magellanic Clouds were originally a triplet system containing this companion galaxy.We then discuss previous observations of the Magellanic Clouds in the context of a triplet dwarf system, and discuss how such a merger could occur.

KW - Galaxies: interactions -Magellanic Clouds

KW - Galaxies: star formation

KW - Galaxies: stellar content

UR - http://www.scopus.com/inward/record.url?scp=85054715941&partnerID=8YFLogxK

U2 - 10.1093/mnrasl/sly143

DO - 10.1093/mnrasl/sly143

M3 - Article

VL - 480

SP - L141-L145

JO - Monthly Notices of the Royal Astronomical Society Letters

JF - Monthly Notices of the Royal Astronomical Society Letters

SN - 1745-3925

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