A deeper look at the impact of minor mergers on the observable properties of the Milky Way
Abstract
We present an overview of our recent work which aims to characterize the impact of host-satellite interactions on the observable properties of Milky Way-like galaxies and, in particular, of our own. Our goals are to characterize how often disc corrugation patterns arise in the Local Universe and what are the main physical mechanisms driving them. We use a suite of fully cosmological high resolution simulations from the Auriga Project to analyze the present-day vertical structure of individual Milky Way-sized models. At redshift zero, about 70 of our galactic discs show strong vertical patterns, with amplitudes that can exceed 2 kpc. Half of these are typical ``integral sign'' warps. The rest are corrugation patterns, similar to those observed in the Milky Way. The associated mean vertical motions can be as large as 30 km/s. These perturbations have a variety of causes such as close encounters with satellites or accretion of misaligned cold gas from halo infall or from mergers. More interestingly, we show examples of how the halo dark matter component can react to distant fly-by interactions by developing overdensity wakes. These responses can induce strong perturbations on a galactic disc, such as warps and lopsidedness and ringing, that can be used to study unseen structure in the outskirts of galaxies. Finally, we discuss the observed vertical perturbations of our Galactic disc and present detailed numerical models for its formation, based on the interaction with the Sagittarius dwarf spheroidal galaxy the Large Magellanic Cloud.
- Publication:
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Boletin de la Asociacion Argentina de Astronomia La Plata Argentina
- Pub Date:
- August 2018
- Bibcode:
- 2018BAAA...60..160G
- Keywords:
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- methods: numerical;
- Galaxy: structure;
- Galaxy: kinematics and dynamics;
- galaxies: interactions