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We study a recently observed gravitational microlensing peak in the V-band light curve of Q2237+0305A using a relatively simple, but highly consistent with the data (the best-fit reduced \chi^2 is very close to 1), physical model. The…

Astrophysics · Physics 2009-11-07 L. J. Goicoechea , D. Alcalde , E. Mediavilla , J. A. Munoz

Multiply-imaged quasars and AGNs observed in the mid-infrared (MIR) range are commonly assumed to be unaffected by the microlensing produced by the stars in their lensing galaxy. In this paper, we investigate the validity domain of this…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-07 D. Sluse , M. Kishimoto , T. Anguita , O. Wucknitz , J. Wambsganss

The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the…

Astrophysics · Physics 2007-05-23 Paul Baillon , Alain Bouquet , Yannick Giraud-Héraud , Jean Kaplan

Microlensing of stars places significant constraints on sub-planetary-mass compact objects, including primordial black holes, as dark matter candidates. As the lens' Einstein radius in the source plane becomes comparable to the size of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-15 Nolan Smyth , Stefano Profumo , Samuel English , Tesla Jeltema , Kevin McKinnon , Puragra Guhathakurta

Microlensing is a powerful technique to study the Galactic population of "dark" objects such as exoplanets both bound and unbound, brown dwarfs, low-luminosity stars, old white dwarfs, neutron stars, and almost the only way to study…

We study different models of dark matter distribution for the halo of our galaxy. In particular, we consider Eddington and King-Michie models, which [C[C, which include anisotropy in the velocity space, and compute in a self-consistent way…

Astrophysics · Physics 2009-10-28 F. De Paolis , G. Ingrosso , Ph. Jetzer

The recent discovery of microlensing of stars in the Large Magellanic Cloud has excited much interest in the nature of the lensing population. Detailed analyses indicate that the mass of these objects ranges from 0.3-0.8 solar masses,…

Astrophysics · Physics 2007-05-23 Brad M. S. Hansen

Since the first discovery of microlensing events nearly two decades ago, gravitational microlensing has accumulated tens of TBytes of data and developed into a powerful astrophysical technique with diverse applications. The review starts…

Astrophysics of Galaxies · Physics 2015-06-05 Shude Mao

The interpretation of microlensing results towards the Large Magellanic Cloud (LMC) still remains controversial. White dwarfs have been proposed to explain these results and, hence, to contribute significantly to the mass budget of our…

Astrophysics · Physics 2009-11-13 J. Camacho , S. Torres , J. Isern , L. G. Althaus , E. Garcia-Berro

It has been shown by Paczy\'nski that gravitational microlensing is potentially a useful method for detecting the dark constituents of the halo of our galaxy, if their mass lies in the approximate domain $10^{-6} < M/M_{\odot} < 10^{-1}$.…

Astrophysics · Physics 2008-02-03 Philippe Jetzer

We have searched for long duration microlensing events originating from intermediate mass Black Holes (BH) in the halo of the Milky Way, using archival data from EROS-2 and MACHO photometric surveys towards the Large Magellanic Cloud. We…

Several massive black holes exhibit flux variability on time scales that correspond to source sizes of the order of few Schwarzschild radii. We survey the potential of near-infrared and X-ray polarimetry to constrain physical properties of…

High Energy Astrophysical Phenomena · Physics 2015-05-27 M. Zamaninasab , A. Eckart , M. Dovciak , V. Karas , R. Schoedel , G. Witzel , N. Sabha , M. Garcia-Marin , D. Kunneriath , K. Muzic , C. Straubmeier , M. Valencia-S , J. A. Zensus

We investigate microlensing amplification of faint stars in the dense stellar cluster in the Galactic Center (GC) by the super-massive black hole (BH). Such events would appear very close to the position of the radio source SgrA*, which is…

Astrophysics · Physics 2009-10-31 Tal Alexander , Amiel Sternberg

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

January 2000 completes the first season of intensive, wide-field observations of microlensing and stellar variability in M31 by MEGA (Microlensing Exploration of the Galaxy and Andromeda) at the Isaac Newton 2.5m Telescope, the KPNO 4m, and…

Astrophysics · Physics 2009-09-25 A. Crotts , R. Uglesich , A. Gould , G. Gyuk , P. Sackett , K. Kuijken , W. Sutherland , L. Widrow

Gravitational microlensing is a powerful tool to search for a population of invisible black holes (BHs) in the Milky Way (MW), including isolated BHs and binary BHs at wide orbits that are complementary to gravitational wave observations.…

Astrophysics of Galaxies · Physics 2021-01-06 Natasha S. Abrams , Masahiro Takada

The simplest interpretation of the microlensing events towards the Large Magellanic Cloud detected by the MACHO and EROS collaborations is that about one third of the halo of our own Milky Way galaxy exists in the form of objects of around…

Astrophysics · Physics 2009-10-30 N. W. Evans , G. Gyuk , M. S. Turner , J. J. Binney

Nearly 150 massive black hole binary (MBHB) candidates at sub-pc orbital separations have been reported in recent literature. Nevertheless, the definitive detection of even a single such object remains elusive. If at least one of the black…

High Energy Astrophysical Phenomena · Physics 2017-12-07 Daniel J. D'Orazio , Rosanne Di Stefano

The discovery of the Sgr dwarf galaxy (Ibata, Gilmore, Irwin 1994) shows that the Galactic halo contains large clumps which are not full viralized. Stars in such a clump can lense a background extragalactic source. I use parameters of Sgr…

Astrophysics · Physics 2008-02-03 HongSheng Zhao

Microlensing has established itself as a powerful new method for the detection of baryonic dark matter in the Galaxy. The theory of microlensing is sketched and its similarity with the optical effect of twinkling is explained. The bulk of…

Astrophysics · Physics 2007-05-23 Wyn Evans