TY - JOUR
T1 - SMASHing the LMC
T2 - A Tidally Induced Warp in the Outer LMC and a Large-scale Reddening Map
AU - Choi, Yumi
AU - Nidever, David L.
AU - Olsen, Knut
AU - Blum, Robert D.
AU - Besla, Gurtina
AU - Zaritsky, Dennis
AU - Van Der Marel, Roeland P.
AU - Bell, Eric F.
AU - Gallart, Carme
AU - Cioni, Maria Rosa L.
AU - Clifton Johnson, L.
AU - Katherina Vivas, A.
AU - Saha, Abhijit
AU - De Boer, Thomas J.L.
AU - Noël, Noelia E.D.
AU - Monachesi, Antonela
AU - Massana, Pol
AU - Conn, Blair C.
AU - Martinez-Delgado, David
AU - Muñoz, Ricardo R.
AU - Stringfellow, Guy S.
N1 - Funding Information:
We are grateful to the referee for providing helpful comments to improve the paper. Y.C. and E.F.B. acknowledge support from NSF grant AST 1655677. M.-R.L.C. acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 682115). A.M. acknowledges partial support from CONICYT FONDECYT regular 1181797. B.C.C. acknowledges the support of the Australian Research Council through Discovery project DP150100862. T.D.B. acknowledges support from the European Research Council (ERC StG-335936). D.M.D. acknowledges support by Sonderforschungsbereich (SFB) 881 “The Milky Way System” of the German Research Foundation (DFG), particularly through subprojects A2. Based on observations at Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory (NOAO Prop. IDs: 2013A-0411 and 2013B-0440; PI: Nidever), which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaboration. Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Cientifico e Tecnológico and the Ministério da Ciência, Tecnologia e Inovação, the Deutsche Forschungsgemeinschaft and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne National Laboratory, the University of California at Santa Cruz, the University of Cambridge, Centro de Investiga-ciones Enérgeticas, Medioambientales y Tecnológicas-Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgenös-sische Technische Hochschule (ETH) Zürich, Fermi National Accelerator Laboratory, the University of Illinois at Urbana-Champaign, the Institut de Ciències de l’Espai (IEEC/CSIC), the Institut de Física d’Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universität München and the associated Excellence Cluster Universe, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, the Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Accelerator Laboratory, Stanford University, the University of Sussex, and Texas A&M University. Facility: Blanco (DECam).
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..
PY - 2018/10/20
Y1 - 2018/10/20
N2 - We present a study of the three-dimensional (3D) structure of the Large Magellanic Cloud (LMC) using ∼2.2 million red clump (RC) stars selected from the Survey of the MAgellanic Stellar History. To correct for line-of-sight dust extinction, the intrinsic RC color and magnitude and their radial dependence are carefully measured by using internal nearly dust-free regions. These are then used to construct an accurate 2D reddening map (165 deg2 area with ∼10′ resolution) of the LMC disk and the 3D spatial distribution of RC stars. An inclined disk model is fit to the 2D distance map, yielding a best-fit inclination angle degrees with random errors of ±0.°19 and line-of-nodes position angle degrees with random errors of ±0.°49. These angles vary with galactic radius, indicating that the LMC disk is warped and twisted likely due to the repeated tidal interactions with the Small Magellanic Cloud (SMC). For the first time, our data reveal a significant warp in the southwestern part of the outer disk starting at ρ ∼ 7° that departs from the defined LMC plane up to ∼4 kpc toward the SMC, suggesting that it originated from a strong interaction with the SMC. In addition, the inner disk encompassing the off-centered bar appears to be tilted up to 5°-15° relative to the rest of the LMC disk. These findings on the outer warp and the tilted bar are consistent with the predictions from the Besla et al. simulation of a recent direct collision with the SMC.
AB - We present a study of the three-dimensional (3D) structure of the Large Magellanic Cloud (LMC) using ∼2.2 million red clump (RC) stars selected from the Survey of the MAgellanic Stellar History. To correct for line-of-sight dust extinction, the intrinsic RC color and magnitude and their radial dependence are carefully measured by using internal nearly dust-free regions. These are then used to construct an accurate 2D reddening map (165 deg2 area with ∼10′ resolution) of the LMC disk and the 3D spatial distribution of RC stars. An inclined disk model is fit to the 2D distance map, yielding a best-fit inclination angle degrees with random errors of ±0.°19 and line-of-nodes position angle degrees with random errors of ±0.°49. These angles vary with galactic radius, indicating that the LMC disk is warped and twisted likely due to the repeated tidal interactions with the Small Magellanic Cloud (SMC). For the first time, our data reveal a significant warp in the southwestern part of the outer disk starting at ρ ∼ 7° that departs from the defined LMC plane up to ∼4 kpc toward the SMC, suggesting that it originated from a strong interaction with the SMC. In addition, the inner disk encompassing the off-centered bar appears to be tilted up to 5°-15° relative to the rest of the LMC disk. These findings on the outer warp and the tilted bar are consistent with the predictions from the Besla et al. simulation of a recent direct collision with the SMC.
KW - Magellanic Clouds Supporting material: data behind figures
KW - galaxies: ISM
KW - galaxies: dwarf
KW - galaxies: interactions
KW - galaxies: structure
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U2 - 10.3847/1538-4357/aae083
DO - 10.3847/1538-4357/aae083
M3 - Article
AN - SCOPUS:85055523582
SN - 0004-637X
VL - 866
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 90
ER -