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Related papers: Statistics Of Microlensing Optical Depth

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An expression is provided for the self-lensing optical depth of the thin LMC disk surrounded by a shroud of stars at larger scale heights. The formula is written in terms of the vertical velocity dispersion of the thin disk population. If…

Astrophysics · Physics 2009-10-31 N. W. Evans , E. J. Kerins

The MACHO Project is a search for dark matter in the form of massive compact halo objects (Machos). Photometric monitoring of millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge is used to…

The MACHO and OGLE collaborations have argued that the three longest duration bulge microlensing events are likely caused by nearby black holes, given the small velocities measured with microlensing parallax and nondetection of the lenses.…

Astrophysics · Physics 2009-11-07 Eric Agol , Marc Kamionkowski , Leon Koopmans , Roger Blandford

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

(Abridged) In this paper we refine the theory of microlensing for a planar distribution of point masses. We derive the macroimage magnification distribution P(A) at high magnification (A-1 >> tau^2) for a low optical depth (tau << 1) lens…

Astrophysics · Physics 2009-10-28 Lev Kofman , Nick Kaiser , Man Hoi Lee , Arif Babul

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

Over the past decade, microlensing has developed into a powerful tool to study stellar astrophysics, especially stellar atmospheres, stellar masses, and binarity. I review this progress. Stellar atmospheres can be probed whenever the source…

Astrophysics · Physics 2016-08-30 Andrew Gould

Current gravitational microlensing surveys are observing hundreds of millions of stars in the Galactic bulge - which makes finding rare microlensing events a challenging tasks. In almost all previous works, microlensing events have been…

Instrumentation and Methods for Astrophysics · Physics 2021-01-06 Przemek Mroz

In order to understand the nature of the lenses that generate microlensing events, one would like to measure their mass, distance, and velocity. Unfortunately, current microlensing experiments measure only one parameter of the events, the…

Astrophysics · Physics 2009-10-28 B. Scott Gaudi , Andrew Gould

The probability of detecting a planetary companion of a lensing star during a microlensing event toward the Galactic center, averaged over all relevant event and galactic parameters, when the planet-star mass ratio $q=0.001$ has a maximum…

Astrophysics · Physics 2009-11-06 S. J. Peale

We used the red clump stars from the Optical Gravitational Lensing Experiment (OGLE II) survey and the the Magellanic Cloud Photometric Survey (MCPS), to estimate the line of sight depth. The observed dispersion in the magnitude and colour…

Astrophysics · Physics 2009-11-13 Annapurni Subramaniam , Smitha Subramanian

We investigate properties of Galactic microlensing events in which a stellar object is lensed by a neutron star. For an all-sky photometric microlensing survey, we determine the number of lensing events caused by $\sim10^{5}$…

Astrophysics of Galaxies · Physics 2015-07-03 Shi Dai , Martin C. Smith , Mengxiang Lin , Youling Yue , George Hobbs , Renxin Xu

Gravitational microlensing is currently the only technique that helps study the Galactic distribution of planets as a function of distance from the Galactic center. The Galactic location of a lens system can be uniquely determined only when…

Earth and Planetary Astrophysics · Physics 2021-09-08 Naoki Koshimoto , David P. Bennett , Daisuke Suzuki , Ian A. Bond

I derive a general expression for the optical depth $\tau$ for gravitational lensing of stars in a disk by Massive Compact Objects (Machos) in the same disk. For the more restricted case where the disk is self-gravitating and the stars and…

Astrophysics · Physics 2009-10-22 Andrew Gould

We present a new analysis of the results of the EROS-2, OGLE-II, and OGLE-III microlensing campaigns towards the Small Magellanic Cloud (SMC). Through a statistical analysis we address the issue of the \emph{nature} of the reported…

Astrophysics of Galaxies · Physics 2013-09-27 S. Calchi Novati , S. Mirzoyan , Ph. Jetzer , G. Scarpetta

We propose a near-infrared microlensing survey of the central 2 degree field of the Galactic Center, in an attempt to estimate the surface density and mass distribution of distant free-floating brown dwarfs in the bulge and in the disk,…

Astrophysics · Physics 2016-08-30 Hans Zinnecker

GAIA is the ``super-Hipparcos'' survey satellite selected as a Cornerstone 6 mission by the European Space Agency. GAIA can measure microlensing by the small excursions of the light centroid that occur during events. The all-sky…

Astrophysics · Physics 2009-11-07 V. A. Belokurov , N. W. Evans

We propose a new method that can be used to constrain the properties of the Galactic bar (bulge). If the majority of the lensing objects are in the Galactic bar, then we predict a systematic offset in the apparent magnitude between lensed…

Astrophysics · Physics 2009-10-22 K. Z. Stanek

Microlensing surveys have discovered thousands of events with almost all events discovered within the Galactic bulge or toward the Magellanic clouds. The Zwicky Transient Facility (ZTF), while not designed to be a microlensing campaign, is…

Solar and Stellar Astrophysics · Physics 2021-02-23 Michael S. Medford , Jessica R. Lu , William A. Dawson , Casey Y. Lam , Nathan R. Golovich , Edward F. Schlafly , Peter Nugent

To provide criteria in the selection of target events preferable for planetary lensing follow-up observations, we investigate the variation of the probability of detecting planetary signals depending on the observables of the lensing…

Astrophysics · Physics 2009-06-23 Cheongho Han