Open AccessMicrolensing in dark matter haloes
Author(s) -
Holopainen Janne,
Flynn Chris,
Knebe Alexander,
Gill Stuart P.,
Gibson Brad K.
Publication year - 2006
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.1365-2966.2006.10205.x
Subject(s) - gravitational microlensing , physics , halo , dark matter , astrophysics , galactic halo , large magellanic cloud , dark matter halo , substructure , milky way , massive compact halo object , gravitational lens , astronomy , galaxy , stars , brown dwarf , redshift , structural engineering , engineering
Using eight dark matter haloes extracted from fully self‐consistent cosmological N ‐body simulations, we perform microlensing experiments. A hypothetical observer is placed at a distance of 8.5 kpc from the centre of the halo measuring optical depths, event durations and event rates towards the direction of the Large Magellanic Cloud. We simulate 1600 microlensing experiments for each halo. Assuming that the whole halo consists of massive astronomical compact halo objects (MACHOs), f = 1.0 , and a single MACHO mass is m M = 1.0 M ⊙ , the simulations yield mean values of τ= 4.7 +5.0 −2.2 × 10 −7 and Γ= 1.6 +1.3 −0.6 × 10 −6 events star −1 yr −1 . We find that triaxiality and substructure can have major effects on the measured values so that τ and Γ values of up to three times the mean can be found. If we fit our values of τ and Γ to the MACHO collaboration observations, we find f = 0.23 +0.15 −0.13 and m M = 0.44 +0.24 −0.16 . Five out of the eight haloes under investigation produce f and m M values mainly concentrated within these bounds.