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Microlensing by stars within distant galaxies acting as strong gravitational lenses of multiply-imaged quasars, provides a unique and direct measurement of the internal structure of the lensed quasar on nano-arcsecond scales. The…

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

Strong gravitational lensing of quasars has the potential to unlock the poorly understood physics of these fascinating objects, as well as serve as a probe of the lensing mass distribution and of cosmological parameters. In particular,…

Astrophysics of Galaxies · Physics 2023-12-05 G. Vernardos , D. Sluse , D. Pooley , R. W. Schmidt , M. Millon , L. Weisenbach , V. Motta , T. Anguita , P. Saha , M. O'Dowd , A. Peel , P. L. Schechter

Gravitational microlensing is a powerful tool for probing the physical properties of quasar accretion disks and properties of the lens galaxy such as its dark matter fraction and mean stellar mass. Unfortunately the number of lensed quasars…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-19 Ana M. Mosquera , Christopher S. Kochanek

We investigate the possibilities that pulsars act as the lens in gravitational microlensing events towards the galactic bulge or a spiral arm. Our estimation is based on expectant survey and observations of FAST (Five hundred meter Aperture…

High Energy Astrophysical Phenomena · Physics 2015-05-14 S. Dai , R. X. Xu , A. Esamdin

We consider the signature and detectability of gravitational microlensing of distant quasars by cosmic strings. Because of the simple image configuration such events will have a characteristic light curve, in which a source would appear to…

Astrophysics · Physics 2009-11-13 Konrad Kuijken , Xavier Siemens , Tanmay Vachaspati

Quasar microlensing is both a very useful tool in cosmology and astrophysics, and a source of uncertainty in some studies like the determination of the Hubble constant from lensed quasars. Microlensing probability and time-scales have been…

Astrophysics of Galaxies · Physics 2026-05-06 F. Ávila-Vera , V. Motta , E. Mediavilla

Microlensing of gravitationally lensed quasars by the stars in the foreground lens galaxy can be used to probe the nature of dark matter, to determine the mean stellar mass in the lens galaxy, and to measure the internal structure of quasar…

Astrophysics · Physics 2007-05-23 C. S. Kochanek , X. Dai , C. Morgan , N. Morgan , S. Poindexter , G. Chartas

Variability in gravitationally lensed quasars can be due to intrinsic fluctuations of the quasar or due to ``microlensing'' by compact objects along the line of sight. If disentangled from each other, microlens-induced variability can be…

Astrophysics · Physics 2007-05-23 Joachim Wambsganss

We present a quantitative analysis of the effect of microlensing caused by random motion of individual stars in the galaxy which is lensing a background quasar. We calculate a large number of magnification patterns for positions of the…

Astrophysics · Physics 2016-08-30 Joachim Wambsganss , Tomislav Kundic

Optical and X-ray observations of strongly gravitationally lensed quasars (especially when four separate images of the quasar are produced) determine not only the amount of matter in the lensing galaxy but also how much is in a smooth…

We present a tool to generate mock quasar microlensing light curves and sample them according to any observing strategy. An updated treatment of the fixed and random velocity components of observer, lens, and source is used, together with a…

Astrophysics of Galaxies · Physics 2020-11-02 Favio Neira , Timo Anguita , Georgios Vernardos

A small fraction of all quasars are strongly lensed and multiply imaged, with usually a galaxy acting as the main lens. Some, maybe all of these quasars are also affected by microlensing, the effects of stellar mass objects in the lensing…

Astrophysics · Physics 2009-11-10 Marie Treyer , Joachim Wambsganss

Gravitational microlensing of planetary-mass objects (or "nanolensing", as it has been termed) can be used to probe the distribution of mass in a galaxy that is acting as a gravitational lens. Microlensing and nanolensing light curve…

Astrophysics of Galaxies · Physics 2015-06-03 H. Garsden , N. F. Bate , G. F. Lewis

We estimate the fraction of mass that is composed of compact objects in gravitational lens galaxies. This study is based on microlensing measurements (obtained from the literature) of a sample of 29 quasar image pairs seen through 20 lens…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 E. Mediavilla , J. A. Munoz , E. Falco , V. Motta , E. Guerras , H. Canovas , C. Jean , A. Oscoz , A. M. Mosquera

Gravitational microlensing method is a powerful method to detect isolated black holes in the Milky Way. During a microlensing event brightness of the source increases and this feature is used by many photometric surveys to alert on…

Solar and Stellar Astrophysics · Physics 2024-02-06 I. Gezer , Ł. Wyrzykowski , P. Zieliński , G. Marton , K. Kruszyńska , K. A. Rybicki , N. Ihanec , M. Jabłońska , O. Ziółkowska

Microlensing events can be used to directly measure the masses of single field stars to a precision of $\sim$1-10\%. The majority of direct mass measurements for stellar and sub-stellar objects typically only come from observations of…

Solar and Stellar Astrophysics · Physics 2018-11-09 M. B. Nielsen , D. M. Bramich

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

In the companion paper we began the task of systematically studying the detection of planets in wide orbits ($a > 1.5 R_E$) via microlensing surveys. In this paper we continue, focusing on repeating events. We find that, if all planetary…

Astrophysics · Physics 2009-10-31 Rosanne Di Stefano , Richard A. Scalzo

The fraction of quasar's and gamma-ray burst (GRB) afterglows that vary due to microlensing by the stellar populations of intervening elliptical/S0 galaxies is computed by combining the joint distribution of effective microlensing…

Astrophysics · Physics 2009-11-07 J. S. B. Wyithe , E. L. Turner
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