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Related papers: Magnification Bias in Galactic Microlensing Search…

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We present a catalog of 450 high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout our fields and, as expected, they show clear concentration toward the…

Stars in globular clusters can act either as sources for MACHOs (Massive Astrophysical Compact Halo Objects) located along the line of sight or as lenses for more distant background stars. Although the expected rate of microlensing events…

Astrophysics · Physics 2007-05-23 P. Jetzer , M. Strässle , U. Wandeler

Gravitational lensing magnification modifies the observed spatial distribution of galaxies and can severely bias cosmological probes of large-scale structure if not accurately modelled. Standard approaches to modelling this magnification…

Extreme magnifications of distant objects by factors of several thousand have recently become a reality. Small very luminous compact objects, such as supernovae (SNe), giant stars at z=1-2, Pop III stars at z>7 and even gravitational waves…

Astrophysics of Galaxies · Physics 2019-05-22 Jose M. Diego

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…

Previous calculations of the rates and optical depths due to microlensing only considered resolved stars. However, if a faint unresolved star lens is close enough to a resolved star, the event will be seen by the microlensing experiments…

Astrophysics · Physics 2007-05-23 C. Alard

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 follow-up observations of a gravitational microlensing candidate found by the MACHO collaboration in the Galactic bulge. The photometric data cover a period near the maximum of the event and may be used to construct complete…

Astrophysics · Physics 2009-09-25 M. Szymanski , A. Udalski , J. Kaluzny , M. Kubiak , W. Krzeminski , M. Mateo

Recently the Polish-American collaboration OGLE has reported the observation of four possible microlensing events by monitoring, over several months, the brightness of millions of stars in the region of the galactic bulge. If these events…

Astrophysics · Physics 2009-10-22 Ph. Jetzer

Foundations of standard theory of microlensing are described, namely we consider microlensing stars in Galactic bulge, the Magellanic Clouds or other nearby galaxies. We suppose that gravitational microlenses lie between an Earth observer…

Astrophysics · Physics 2017-08-23 Alexander F. Zakharov

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…

We present preliminary results of the analysis of 5 years of MACHO data on the Galactic bulge microlensing events with clump giants as sources. This class of events allows one to obtain robust conclusions because relatively bright clump…

After a decade of gravitational microlensing experiments, 13 to 17 events by MACHO (depending on quality) and two events by EROS have been detected. All of those have been observed in the direction of Large Magellanic Cloud. We use Evans…

Astrophysics · Physics 2009-11-07 Sohrab Rahvar

Massive objects located between Earth and a compact binary merger can act as a magnifying glass improving the sensitivity of gravitational wave detectors to distant events. Depending on the parameters of the system, a point mass lens…

General Relativity and Quantum Cosmology · Physics 2023-10-27 Ruxandra Bondarescu , Helena Ubach , Oleg Bulashenko , Andrew P. Lundgren

By monitoring $10^6$ quasars one could search for lensing by stars and Massive Compact Halo Objects (Machos) out to redshifts $z\sim 4$. If Machos have a present cosmological density $\Omega_{L,0}=1\%$, then the expected event rate is…

Astrophysics · Physics 2009-10-28 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

The POINT-AGAPE collaboration is carrying out a search for gravitational microlensing toward M31 to reveal galactic dark matter in the form of MACHOs (Massive Astrophysical Compact Halo Objects) in the halos of the Milky Way and M31. A…

To reveal the galactic dark matter in the form of MACHOs ("Massive Astrophysical Compact Halo Objects"), the POINT-AGAPE collaboration is carrying out a search for gravitational microlensing towards M31. A clear microlensing signal is…

Astrophysics · Physics 2007-05-23 S. Paulin-Henriksson , S. Calchi Novati

Strong gravitational lensing of gravitational waves (GWs) has been forecasted to become detectable in the upcoming observing runs. However, definitively distinguishing pairs of lensed sources from random associations is a challenging…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Mesut Çalışkan , Jose María Ezquiaga , Otto A. Hannuksela , Daniel E. Holz

Currently, gravitational microlensing survey experiments toward the Galactic bulge field utilize two different methods of minimizing blending effect for the accurate determination of the optical depth \tau. One is measuring \tau based on…

Astrophysics · Physics 2009-11-13 Cheongho Han