Open AccessOn mini‐halo encounters with stars
Author(s) -
Green Anne M.,
Goodwin Simon P.
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2007.11397.x
Subject(s) - physics , halo , stars , astrophysics , milky way , dark matter , impulse (physics) , velocity dispersion , dark matter halo , mass distribution , classical mechanics , galaxy
We study, analytically and numerically, the energy input into dark matter mini‐haloes by interactions with stars. We find that the fractional energy input in simulations of Plummer spheres agrees well with the impulse approximation for small and large impact parameters, with a rapid transition between these two regimes. Using the impulse approximation, the fractional energy input at large impact parameters is fairly independent of the mass and density profiles of the mini‐halo; however, low‐mass mini‐haloes experience a greater fractional energy input in close encounters. We formulate a fitting function which encodes these results and use it to estimate the disruption time‐scales of mini‐haloes, taking into account the stellar velocity dispersion and mass distribution. For mini‐haloes with mass on typical orbits which pass through the disc, we find that the estimated disruption time‐scales are independent of mini‐halo mass, and are of the order of the age of the Milky Way. For more massive mini‐haloes, the estimated disruption time‐scales increase rapidly with increasing mass.