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| Paper: |
M31’s Giant Southern Stream: Constraints on the Progenitor’s Mass, Phase, and Rotation |
| Volume: |
419, Galaxy Evolution: Emerging Insights and Future Challenges |
| Page: |
118 |
| Authors: |
Fardal, M.; Guhathakurta, P.; Gilbert, K.; Babul, A.; Dodge, C.; Weinberg, M. D.; Lu, Y. |
| Abstract: |
We use N-body simulations to investigate the origin of the Giant Southern Stream in M31. Our model suggests the stream resulted from the disruption of a large satellite galaxy less than 1 Gyr ago, and connects it to other debris structures in M31’s halo. The stream pumps a significant fraction of the progenitor’s mass into M31’s outer reaches, demonstrating the ongoing buildup of galaxy stellar halos. Rotating models give better fits to the observed stream structure than spherical models, adding a constraint on the progenitor’s nature. We use Bayesian sampling of the simulations to get a preliminary estimate of the progenitor’s initial mass Msat = (3.5±0.5) × 109 Msun, which would make it one of the most massive Local Group galaxies. We find its current orbital phase to be 1.1±0.1 radial periods past disruption, suggesting any intact remnant lies against the NE portion of M31’s disk. |
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