SIMBAD references

2025ApJ...988...79R - Astrophys. J., 988, 79 (2025/July-3)

Response of the LMC's Bar to a Recent SMC Collision and Implications for the SMC's Dark Matter Profile.

RATHORE H., BESLA G., DANIEL K.J. and BERALDO E SILVA L.

Abstract (from CDS):

The LMC's stellar bar is offset from the outer disk center, tilted from the disk plane, and does not drive gas inflows. These properties are atypical of bars in gas-rich galaxies, yet the LMC bar's strength and radius are similar to typical barred galaxies. Using N-body hydrodynamic simulations, we show that the LMC's unusual bar is explainable if there was a recent collision (impact parameter ≈2 kpc) between the LMC and SMC. Pre-collision, the simulated bar is centered and coplanar. Post-collision, the simulated bar is offset (≈1.5 kpc) and tilted (≈8$\mathop{.}\limits^{\unicode{x000b0}}$6). The simulated bar offset reduces with time, and comparing with the observed offset (≈0.8 kpc) suggests the timing of the true collision to be 150-200 Myr ago. Then, 150 Myr post-collision, the LMC's bar is centered with its dark matter (DM) halo, whereas the outer disk center is separated from the DM center by ≈1 kpc. The SMC collision produces a tilted-ring structure for the simulated LMC, consistent with observations. Post-collision, the simulated LMC bar's pattern speed decreases by a factor of 2. We also provide a generalizable framework to quantitatively compare the LMC's central gas distribution in different LMC-SMC interaction scenarios. We demonstrate that the SMC's torques on the LMC's bar during the collision are sufficient to explain the observed bar tilt, provided the SMC's total mass within 2 kpc was (0.8-2.4) × 109M⊙. Therefore, the LMC bar's tilt constrains the SMC's pre-collision DM profile, and requires the SMC to be a DM-dominated galaxy.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Large Magellanic Cloud - Small Magellanic Cloud - Galaxy bars - Hydrodynamical simulations - Galaxy interactions - Dwarf galaxies

Simbad objects: 3

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