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A Lonely Giant: The Sparse Satellite Population of M94 Challenges Galaxy Formation by Adam Smercina; Eric F. Bell; Paul A. Price; Richard D’Souza; Colin T. Slater; Jeremy Bailin; Antonela Monachesi; David Nidever is a Physics and Astronomy article available to read on EtoBox.

What is A Lonely Giant: The Sparse Satellite Population of M94 Challenges Galaxy Formation about?

The dwarf satellites of "giant" Milky Way (MW)-mass galaxies are our primary probes of low-mass dark matter halos. The number and velocities of the satellite galaxies of the MW and M31 initially puzzled galaxy formation theorists, but are now reproduced well by many models. Yet, are the MW's and M31ʼs satellites representative? Were galaxy formation models "overfit"? These questions motivate deep searches for satellite galaxies outside the Local Group. We present a deep survey of the "classical" satellites (M å 4×10 5 M e ) of the MW-mass galaxy M94 out to a 150 kpc projected distance. We find only two satellites, each with M å ∼10 6 M e , compared with 6-12 such satellites in the four other MW-mass systems with comparable data (MW, M31, M81, and M101). Using a "standard" prescription for occupying dark matter halos (halos were taken from the fully hydrodynamical EAGLE simulation) with galaxies, we find that such a sparse satellite population occurs in <0.2% of MW-mass systems-a <1% probability among a sample of five (known systems + M94). In order to produce an M94-like system more frequently we make satellite galaxy formation much more stochastic than is currently predicted

Who reads A Lonely Giant: The Sparse Satellite Population of M94 Challenges Galaxy Formation?

Author

Adam Smercina; Eric F. Bell; Paul A. Price; Richard D’Souza; Colin T. Slater; Jeremy Bailin; Antonela Monachesi; David Nidever

Publisher

University of Chicago Press; American Astronomical Society; Institute of Physics Publishing; IOP Publishing; Oxford University Press (OUP) (ISSN 0004-637X)

Published

2018

Language

EN

Field

Physics and Astronomy (Physical Sciences)