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arXiv · 1603.09498

The tangential velocity of M31: CLUES from constrained simulations

Edoardo Carlesi·Yehuda Hoffman·Jenny G. Sorce·Stefan Gottloeber·Gustavo Yepes·Helene Courtois·R. Brent Tully
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Abstract

Determining the precise value of the tangential component of the velocity of M31 is a non trivial astrophysical issue, that relies on complicated modeling. This has recently lead to con- flicting estimates, obtained by several groups that used different methodologies and assump- tions. This letter addresses the issue by computing a Bayesian posterior distribution function of this quantity, in order to measure the compatibility of those estimates with LambdaCDM. This is achieved using an ensemble of local group (LG) look-alikes collected from a set of Con- strained Simulations (CSs) of the local Universe, and a standard unconstrained LambdaCDM. The latter allows us to build a control sample of LG-like pairs and to single out the influence of the environment in our results. We find that neither estimate is at odds with LambdaCDM; how- ever, whereas CSs favour higher values of vtan , the reverse is true for estimates based on LG samples gathered from unconstrained simulations, overlooking the environmental element

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Edoardo Carlesi, Yehuda Hoffman, Jenny G. Sorce, Stefan Gottloeber, Gustavo Yepes, Helene Courtois, R. Brent Tully. 2016-03-31. The tangential velocity of M31: CLUES from constrained simulations. https://doi.org/10.1093/mnrasl/slw059

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