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A stellar overdensity associated with the Small Magellanic Cloud

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posted on 2023-06-09, 06:12 authored by Kathy RomerKathy Romer, The DES Collaboration
We report the discovery of a stellar overdensity 8° north of the centre of the Small Magellanic Cloud (SMC; Small Magellanic Cloud Northern Over-Density; SMCNOD), using data from the first 2 yr of the Dark Energy Survey (DES) and the first year of the MAGellanic SatelLITEs Survey (MagLiteS). The SMCNOD is indistinguishable in age, metallicity and distance from the nearby SMC stars, being primarily composed of intermediate-age stars (6 Gyr, Z=0.001), with a small fraction of young stars (1 Gyr, Z=0.01). The SMCNOD has an elongated shape with an ellipticity of 0.6 and a size of ~ 6° × 2°. It has an absolute magnitude of MV ? -7.7, rh = 2.1 kpc, and µV(r < rh) = 31.2 mag arcsec-2. We estimate a stellar mass of ~105 M?, following a Kroupa mass function. The SMCNOD was probably removed from the SMC disc by tidal stripping, since it is located near the head of the Magellanic Stream, and the literature indicates likely recent Large Magellanic Cloud-SMC encounters. This scenario is supported by the lack of significant Hi gas. Other potential scenarios for the SMCNOD origin are a transient overdensity within the SMC tidal radius or a primordial SMC satellite in advanced stage of disruption.

Funding

Astronomy Centre Rolling Grant; G0679; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/F002858/1

History

Publication status

  • Published

File Version

  • Published version

Journal

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

Publisher

Oxford University Press

Issue

2

Volume

468

Page range

1349-1360

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Astronomy Centre Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2017-05-09

First Open Access (FOA) Date

2017-05-09

First Compliant Deposit (FCD) Date

2017-05-09

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