Bibcode
Choi, Yumi; Nidever, David L.; Olsen, Knut; Blum, Robert D.; Besla, Gurtina; Zaritsky, Dennis; van der Marel, Roeland P.; Bell, Eric F.; Gallart, Carme; Cioni, Maria-Rosa L.; Johnson, L. Clifton; Vivas, A. Katherina; Saha, Abhijit; de Boer, Thomas J. L.; Noël, Noelia E. D.; Monachesi, Antonela; Massana, Pol; Conn, Blair C.; Martinez-Delgado, David; Muñoz, Ricardo R.; Stringfellow, Guy S.
Bibliographical reference
The Astrophysical Journal, Volume 866, Issue 2, article id. 90, 19 pp. (2018).
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10
2018
Journal
Citations
78
Refereed citations
73
Description
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 i={25.86}-1.39+0.73
degrees with random errors of ±0.°19 and line-of-nodes
position angle θ ={149.23}-8.35+6.43
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.
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Galaxy formation and evolution is a fundamental Astrophysical problem. Its study requires “travelling back in time”, for which there are two complementary approaches. One is to analyse galaxy properties as a function of red-shift. Our team focuses on the other approach, called “Galactic Archaeology”. It is based on the determination of galaxy
Matteo
Monelli