Inventory of Gravitational Microlenses toward the Galactic Bulge

dc.creatorHan, Cheongho
dc.creatorLee, Seunghun
dc.date1997-05-19
dc.date.accessioned2026-07-07T02:23:23Z
dc.date.available2026-07-07T02:23:23Z
dc.descriptionWe determine the microlensing event rate distribution, $Γ(t_{E})$, that is properly normalized by the first year MACHO group observations (Alcock et al. 1997). By comparing the determined $Γ(t_{E})$ with various MF models of lens populations to the observed distribution, we find that stars and WDs explain just $\sim 49%$ of the total event rate and $\sim 37%$ of the observationally determined optical depth even including very faint stars just above hydrogen-burning limit. Additionally, the expected time scale distribution of events caused by these known populations of lenses deviates significantly from the observed distribution especially in short time scale region. However, if the rest of the dynamically measured mass of the bulge ($\sim 2.1\times 10^{10} M_\odot$) is composed of brown dwarfs, both expected and observed event rate distribution matches very well.
dc.description15 pages including 1 tables and 4 figures, submitted to ApJ
dc.identifierhttps://arxiv.org/abs/astro-ph/9705137
dc.identifierhttp://arxiv.org/abs/astro-ph/9705137
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/11230
dc.subjectAstrophysics
dc.titleInventory of Gravitational Microlenses toward the Galactic Bulge
dc.typetext

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