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Hypervelocity runaways from the Large Magellanic Cloud

Published version
Peer-reviewed

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Authors

Boubert, D 
Erkal, D 
Evans, NW 
Izzard, RG 

Abstract

We explore the possibility that the observed population of Galactic hypervelocity stars (HVSs) originate as runaway stars from the Large Magellanic Cloud (LMC). Pairing a binary evolution code with an N-body simulation of the interaction of the LMC with the Milky Way, we predict the spatial distribution and kinematics of an LMC runaway population. We find that runaway stars from the LMC can contribute Galactic HVSs at a rate of 3 × 10¯⁶ yr‾¹. This is composed of stars at different points of stellar evolution, ranging from the main sequence to those at the tip of the asymptotic giant branch. We find that the known B-type HVSs have kinematics that are consistent with an LMC origin. There is an additional population of hypervelocity white dwarfs whose progenitors were massive runaway stars. Runaways that are even more massive will themselves go supernova, producing a remnant whose velocity will be modulated by a supernova kick. This latter scenario has some exotic consequences, such as pulsars and supernovae far from star-forming regions, and a small rate of microlensing from compact sources around the halo of the LMC.

Description

Keywords

binaries: general, stars: kinematics and dynamics, supernovae: general, Magellanic Clouds

Journal Title

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

469

Publisher

Oxford University Press
Sponsorship
Science and Technology Facilities Council (ST/L003910/1)
Science and Technology Facilities Council (ST/N000927/1)
European Research Council (308024)
DB is grateful to the Science and Technology Facilities Council (STFC) for providing PhD funding. DE acknowledges that research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no. 308024. RGI thanks the STFC for funding his Rutherford fellowship under grant ST/L003910/1 and Churchill College, Cambridge for his fellowship.