Exploring the Very Extended Low-surface-brightness Stellar Populations of the Large Magellanic Cloud with SMASH

Nidever, David L., Olsen, Knut, Choi, Yumi, Boer, Thomas J. L. de, Blum, Robert D., Bell, Eric F., Zaritsky, Dennis, Martin, Nicolas F., Saha, Abhijit, Conn, Blair C. et al, Besla, Gurtina, Marel, Roeland P. van der, Noel, N.E.D, Monachesi, Antonela, Stringfellow, Guy S., Massana, Pol, Cioni, Maria-Rosa L., Gallart, Carme, Monelli, Matteo, Martinez-Delgado, David, Muñoz, Ricardo R., Majewski, Steven R., Vivas, A. Katherina, Walker, Alistair R., Kaleida, Catherine and Chu, You-Hua (2019) Exploring the Very Extended Low-surface-brightness Stellar Populations of the Large Magellanic Cloud with SMASH The Astrophysical Journal, 874 (2), 118.

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Abstract

We present the detection of very extended stellar populations around the Large Magellanic Cloud (LMC) out to R ~ 21°, or ~18.5 kpc at the LMC distance of 50 kpc, as detected in the Survey of the Magellanic Stellar History (SMASH) performed with the Dark Energy Camera on the NOAO Blanco 4 m Telescope. The deep (g ~ 24) SMASH color–magnitude diagrams (CMDs) clearly reveal old (~9 Gyr), metal-poor ([Fe/H] ≈ −0.8 dex) main-sequence stars at a distance of ~50 kpc. The surface brightness of these detections is extremely low with our most distant detection at Σ g ≈ 34 mag arcsec−2. The SMASH radial density profile breaks from the inner LMC exponential decline at ~13°–15° and a second component at larger radii has a shallower slope with power-law index α = −2.2 that contributes ~0.4% of the LMC's total stellar mass. In addition, the SMASH densities exhibit large scatter around our best-fit model of ~70% indicating that the envelope of stellar material in the LMC periphery is highly disturbed. We also use data from the NOAO Source catalog to map the LMC main-sequence populations at intermediate radii and detect a steep dropoff in density on the eastern side of the LMC (at R ≈ 8°) as well as an extended structure to the far northeast. These combined results confirm the existence of a very extended, low-density envelope of stellar material with a disturbed shape around the LMC. The exact origin of this structure remains unclear, but the leading options include an accreted halo or tidally stripped outer disk material.

Item Type:	Article
Divisions :	Faculty of Engineering and Physical Sciences > Physics
Authors :	Name Email ORCID Nidever, David L. Olsen, Knut Choi, Yumi Boer, Thomas J. L. de Blum, Robert D. Bell, Eric F. Zaritsky, Dennis Martin, Nicolas F. Saha, Abhijit Conn, Blair C. Besla, Gurtina Marel, Roeland P. van der Noel, N.E.D n.noel@surrey.ac.uk Monachesi, Antonela Stringfellow, Guy S. Massana, Pol Cioni, Maria-Rosa L. Gallart, Carme Monelli, Matteo Martinez-Delgado, David Muñoz, Ricardo R. Majewski, Steven R. Vivas, A. Katherina Walker, Alistair R. Kaleida, Catherine Chu, You-Hua
Date :	28 March 2019
DOI :	10.3847/1538-4357/aafaf7
Copyright Disclaimer :	© 2019. The American Astronomical Society. All rights reserved.
Additional Information :	Embargo OK Metadata OK No Further Action
Depositing User :	James Marshall
Date Deposited :	21 Aug 2020 08:34
Last Modified :	21 Aug 2020 08:34
URI:	http://epubs.surrey.ac.uk/id/eprint/858459

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