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Related papers: The MACHO project: Microlensing Optical Depth towa…

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The MACHO collaboration has recently analyzed 2.1 years of photometric data for about 8.5 million stars in the Large Magellanic Cloud (LMC). This analysis has revealed 8 candidate microlensing events and a total microlensing optical depth…

To improve photometric precision by removing blending effect, a newly developed technique of difference image analysis (DIA) is adopted by several gravitational microlensing experiment groups. However, the principal problem of the DIA…

Astrophysics · Physics 2009-10-31 Cheongho Han

We have monitored 8.6 million stars in the Large Magellanic Cloud for 1.1 years and have found 3 events consistent with gravitational microlensing. We place strong constraints on the Galactic halo content in the form of compact lensing…

(Abridged version): The optical depth is widely used in Galactic microlensing studies as a means to determine the density of MACHOs, since in theory it depends only upon their spatial distribution and is therefore less model-dependent than…

Astrophysics · Physics 2009-10-30 E. J. Kerins

For the first time we detected microlensing events at zero latitude in the Galactic bulge using the VISTA Variables in the Via Lactea Survey (VVV) data. We have discovered a total sample of N = 630 events within an area covering 20.7 sq.…

One of the most important problems in astrophysics concerns the nature of the dark matter in galactic halos, whose presence is implied mainly by the observed flat rotation curves in spiral galaxies. In the framework of a baryonic scenario…

Astrophysics · Physics 2007-05-23 Philippe Jetzer

We compute the predicted optical depth and duration distribution of microlensing events towards Baade's window in a model composed of a Galactic disk and a bar. The bar model is a self-consistent dynamical model built out of individual…

Astrophysics · Physics 2009-10-22 HongSheng Zhao , David N. Spergel , R. Michael Rich

We developed a parametric Galactic model toward the Galactic bulge by fitting to spatial distributions of the Gaia DR2 disk velocity, VVV proper motion, BRAVA radial velocity, OGLE-III red clump star count, and OGLE-IV star count and…

Astrophysics of Galaxies · Physics 2021-08-25 Naoki Koshimoto , Junichi Baba , David P. Bennett

We calculate the optical depth and the number of events due to gravitational microlensing towards the Galactic bulge, the spiral arm directions $\gamma$ Scutum, $\beta$ Scutum, $\gamma$ Normae, $\vartheta$ Muscae and some dwarf galaxies in…

Astrophysics · Physics 2007-05-23 Lukas Grenacher , Philippe Jetzer , Marcus Strässle , Francesco De Paolis

In a recent series of three papers, Belokurov, Evans, and Le Du, and Evans and Belokurov, reanalysed the MACHO collaboration data and gave alternative sets of microlensing events and an alternative optical depth to microlensing toward the…

Astrophysics · Physics 2009-11-10 Kim Griest , Christian L. Thomas

Modern surveys of gravitational microlensing events have progressed to detecting thousands per year. Surveys are capable of probing Galactic structure, stellar evolution, lens populations, black hole physics, and the nature of dark matter.…

We present the photometry and theoretical models for a Galactic bulge microlensing event OGLE-2000-BUL-43. The event is very bright with I=13.54 mag, and has a very long time scale, t_E=156 days. The long time scale and its light curve…

We examine the most recent observational constraints arising from i) small-scale and large-scale Galactic dynamical properties, ii) star counts at faint magnitude and iii) microlensing experiments. From these constraints, we determine the…

Astrophysics · Physics 2007-05-23 D. Méra , G. Chabrier , R. Schaeffer

Upcoming LSST survey gives an unprecedented opportunity for studying populations of intrinsically faint objects using microlensing technique. Large field of view and aperture allow effective time-series observations of many stars in…

Instrumentation and Methods for Astrophysics · Physics 2019-02-13 Sedighe Sajadian , Radoslaw Poleski

The initial results of microlensing surveys toward the Galactic bulge and the LMC are puzzling. Toward the LMC, the total mass in MACHOs is of order half that required to explain the dark matter, but the estimated MACHO mass (~0.4 Msun) is…

Astrophysics · Physics 2016-01-27 Andrew Gould

The high-magnification microlensing event MACHO-97-BLG-28 was previously determined to be a binary system composed either of two M dwarfs, or an M dwarf and a brown dwarf. We present a revised light-curve model using additional data from…

Microlensing searches toward the inner galaxy $(|l|,|b|\leq 22.\hskip-2pt'5)$ have several major advantages. First, the event rate is strongly dominated by bulge-bulge lensing events where both the source and lens lie in the bulge. Second,…

Astrophysics · Physics 2009-10-22 Andrew Gould

The EROS microlensing survey has monitored nearly 100 million stars for seven years, to search for halo brown dwarfs and compact objects in the Galactic disk. In this paper, we review the various EROS observation programs and the…

Astrophysics · Physics 2007-05-23 R. Ansari

We present an analysis of the light curves of 9.1 million stars observed during three seasons by EROS (Experience de Recherche d'Objets Sombres), in the Galactic plane away from the bulge. Seven stars exhibit luminosity variations…

Astrophysics · Physics 2012-08-27 EROS Collaboration

The MACHO project has been monitoring about ten million stars in the Large Magellanic Cloud in the search for gravitational microlensing events caused by massive compact halo objects (Machos) in the halo of the Milky Way. In our standard…