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We provide a status report on our search for dark matter in our Galaxy in the form of massive compact halo objects (or Machos), using gravitational microlensing of background stars. This search uses a very large format CCD camera on the…

Stellar microlensing is a powerful method to constrain compact dark matter models, uncover binary stars, and exoplanets during caustic crossing events. At cosmological distances, {\it James-Webb Space Telescope} ({\it JWST}) is routinely…

Astrophysics of Galaxies · Physics 2026-04-14 Sung Kei Li , Thomas Broadhurst , Jose M. Diego , Jeremy Lim , Jose M. Palencia , James Nianias

Geometrical optics provides an excellent description for quasar images crossing caustics which are formed by gravitational microlensing of objects like Q2237+0305. Within this approximation the source size can be estimated from the maximum…

Astrophysics · Physics 2016-08-30 M. Jaroszynski , B. Paczynski

Black hole-like objects with mass greater than $10 M_{\odot}$, as discovered by gravitational antennas, can produce long time-scale (several years) gravitational microlensing effects. Considered separately, previous microlensing surveys…

Astrophysics of Galaxies · Physics 2022-06-13 Tristan Blaineau , Marc Moniez

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 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

Recent discussion of the effects of finite source size on high magnification microlensing events due to MACHOs motivates a study into the feasibility of observing such effects and extracting the source radius. Simulated observations are…

Astrophysics · Physics 2009-10-28 Eric Peng

In the context of this paper, microlenses present as oblate clusters of dark matter structures called massive astrophysical compact halo object(MACHO) in the galactic halo are considered. The NFW density profile [1] is derived from the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Tabib Rayed Hossain , Prabir Kumar Haldar , Mehedi Kalam

The Cosmic-Ray Extremely Distributed Observatory (CREDO) is an infrastructure for global analysis of extremely extended cosmic-ray phenomena, so-called super-preshowers, beyond the capabilities of existing, discrete, detectors and…

We study light variability of gravitationally magnified high-redshift star clusters induced by a foreground population of microlenses. This arises as the incoherent superposition of light variations from a large number of source stars…

Astrophysics of Galaxies · Physics 2021-01-13 Liang Dai

The microlensing signal in the light curves of gravitationally lensed quasars can shed light on the dark matter (DM) composition in their lensing galaxies. Here, we investigate a sample of six lensed quasars from the most recent and best…

Astrophysics of Galaxies · Physics 2023-04-05 Petra Awad , James H. H. Chan , Martin Millon , Frederic Courbin , Eric Paic

Microlensing studies of quasars can reveal dark matter lumps over a broad mass spectrum; we highlight the importance of monitoring quasars which are seen through the halos of low-redshift galaxies. For these configurations microlensing by…

Astrophysics · Physics 2009-10-30 Mark A. Walker

We present the lightcurves of 21 gravitational microlensing events from the first six years of the MACHO Project gravitational microlensing survey which are likely examples of lensing by binary systems. These events were manually selected…

Astrophysics · Physics 2012-08-27 MACHO , GMAN collaborations , : , C. Alcock et al

Can the standard cosmological model be questioned on the basis of a single observed extreme galaxy cluster? Usually, the word extreme refers directly to cluster mass, which is not a direct observable and thus subject to substantial…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-31 Jean-Claude Waizmann , Matthias Redlich , Matthias Bartelmann

Supermagnified stars are gravitationally lensed individual stars that are located close to a caustic of a lensing galaxy cluster, and have their flux magnified by a large enough factor (typically ~ 1000) to make them detectable with present…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-04 Claudi Vall Müller , Jordi Miralda-Escudé

Dark matter subhalos with extended profiles and density cores, and globular stars clusters of mass $10^6-10^8 M_\odot$, that live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing…

We present the analysis of the light curves of 8.5 million stars observed during two seasons by EROS (Experience de Recherche d'Objets Sombres), in the galactic plane away from the bulge. Three stars have been found that exhibit luminosity…

Astrophysics · Physics 2008-11-26 F. Derue , C. Afonso , C. Alard , J-N. Albert

Recent discoveries of circumbinary planets in Kepler data show that there is a viable channel of planet formation around binary main sequence stars. Motivated by these discoveries, we have investigated the caustic structures and…

Earth and Planetary Astrophysics · Physics 2016-08-17 Jacob K. Luhn , Matthew T. Penny , B. Scott Gaudi

We investigate the possibility of lens mass determination for a caustic crossing microlensing event based on a space telescope observation. We demonstrate that the parallax due to the orbital motion of a space telescope causes a periodic…

Astrophysics · Physics 2009-10-31 Mareki Honma

If the dark halo matter is primarily composed of MACHOs toward the lower end of the possible detection range ($ < 10^{-3}$ $M_{\odot}$) a fraction of the lens detection events should involve the lens crossing directly in front of the disk…

Astrophysics · Physics 2009-10-22 Robert J. Nemiroff , W. A. D. Thulsi Wickramasinghe
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