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Related papers: A Parametric Galactic Model toward the Galactic Bu…

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We use the timescale distribution of ~3000 microlensing events measured by the OGLE-III survey, together with accurate new made-to-measure dynamical models of the Galactic bulge/bar region, to measure the IMF in the inner Milky Way. The…

Astrophysics of Galaxies · Physics 2017-07-26 Christopher Wegg , Ortwin Gerhard , Matthieu Portail

Aims. We seek to probe the Galactic bulge IMF starting from microlensing observations. Methods. We analyse the recent results of the microlensing campaigns carried out towards the Galactic bulge presented by the EROS, MACHO and OGLE…

Astrophysics · Physics 2009-06-23 S. Calchi Novati , F. De Luca , Ph. Jetzer , L. Mancini , G. Scarpetta

The number and properties of observed gravitational microlensing events depend on the distribution and kinematics of stars and other compact objects along the line of sight. In particular, precise measurements of the microlensing optical…

We present measurements of the microlensing optical depth and event rate toward the Galactic bulge using the dataset from the 2006--2014 MOA-II survey, which covers 22 bulge fields spanning ~42 deg^2 between -5 deg < l < 10 deg and -7 deg <…

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 a luminosity function (LF) for lower main sequence stars in the Galactic bulge near (l,b)=(0,-6) to J=24, corresponding to M_J~9.3. This LF is derived from HST + NICMOS observations with the F110W and F160W filters. The main…

Astrophysics · Physics 2009-10-31 M. Zoccali , S. Cassisi , J. A. Frogel , A. Gould , S. Ortolani , A. Renzini , R. M. Rich , A. W. Stephens

We use recent microlensing observations toward the central bulge of the Galaxy to probe the overall stellar plus brown dwarf initial mass function (IMF) in these regions well within the brown dwarf domain. We find that the IMF is consistent…

Astrophysics of Galaxies · Physics 2023-02-22 Gilles Chabrier , Romain Lenoble

Perhaps as many as 30 parallax microlensing events are known, thanks to the efforts of the MACHO, OGLE, EROS and MOA experiments monitoring the bulge. Using Galactic models, we construct mock catalogues of microlensing light curves towards…

Astrophysics · Physics 2009-11-11 M. C. Smith , V. Belokurov , N. W. Evans , S. Mao , J. H. An

In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based…

Microlensing provides a unique tool to break the stellar to dark matter degeneracy in the inner Milky Way. We combine N-body dynamical models fitted to the Milky Way's Boxy/Peanut bulge with exponential disk models outside this, and compute…

Astrophysics of Galaxies · Physics 2016-08-17 Christopher Wegg , Ortwin Gerhard , Matthieu Portail

Context: Gravitational microlensing is sensitive to compact-object lenses in the Milky Way, including white dwarfs, neutron stars or black holes, and could potentially probe a wide range of stellar remnant masses. However, the mass of the…

Solar and Stellar Astrophysics · Physics 2020-04-14 Łukasz Wyrzykowski , Ilya Mandel

We analyze the first-year MACHO collaboration observations of microlensing towards the Galactic center using a new direct likelihood technique that is sensitive to the distribution of the events on the sky. We consider the full set of 41…

Astrophysics · Physics 2007-05-23 Geza Gyuk

We present a statistical assessment of both, observed and reported, photometric uncertainties in the OGLE-IV Galactic bulge microlensing survey data. This dataset is widely used for the detection of variable stars, transient objects,…

Instrumentation and Methods for Astrophysics · Physics 2016-04-08 J. Skowron , A. Udalski , S. Kozłowski , M. K. Szymański , P. Mróz , Ł. Wyrzykowski , R. Poleski , P. Pietrukowicz , K. Ulaczyk , M. Pawlak , I. Soszyński

We present the microlensing optical depth towards the Galactic bulge based on the detection of 99 events found in our Difference Image Analysis (DIA) survey. This analysis encompasses three years of data, covering ~ 17 million stars in ~ 4…

We construct a large set of dynamical models of the galactic bulge, bar and inner disk using the Made-to-Measure method. Our models are constrained to match the red clump giant density from a combination of the VVV, UKIDSS and 2MASS…

Astrophysics of Galaxies · Physics 2016-12-21 Matthieu Portail , Ortwin Gerhard , Christopher Wegg , Melissa Ness

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

With the steady increase of the sample size of observed microlenses towards the central regions of the Galaxy, the main source of the uncertainty in the lens mass will shift from the simple Poisson noise to the intrinsic non-uniqueness of…

Astrophysics · Physics 2009-10-30 HongSheng Zhao , P. Tim de Zeeuw

Gravitational microlensing depends primarily on the lens mass and presents a larger occurrence rate in crowded regions, which makes it the best tool to uncover the initial mass function (IMF) of low-mass stars in the Galactic bulge. The…

We build a stellar-dynamical model of the Milky Way barred bulge and disk, using a newly implemented adaptive particle method. The underlying mass model has been previously shown to match the Galactic near-infrared surface brightness as…

Astrophysics · Physics 2009-11-10 Nicolai Bissantz , Victor P. Debattista , Ortwin Gerhard

We present the Catalog of microlensing events detected toward the Galactic bulge in three observing seasons, 1997--1999, during the OGLE-II microlensing survey. The search for microlensing events was performed using a database of about…

Astrophysics · Physics 2007-05-23 A. Udalski , K. Zebrun , M. Szymanski , M. Kubiak , G. Pietrzynski , I. Soszynski , P. Wozniak
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