The Gravitational Lens Effect

Refsdal, S.; Bondi, Hermann

doi:10.1093/mnras/128.4.295

Cited by 438 publications

(259 citation statements)

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“…This procedure delivers a quality index for each light curve related to how similar it is with a microlensing curve. It is then necessary to cull the sample by selecting the curves with higher quality indices for subsequent visual inspection, but before that it is crucial to perform the fitting procedure using the simplest model, assuming a point source and a point lens (PSPL; Refsdal 1964). Where F FA u t s = ( ( )), with F being the observed and F s the catalog source flux, for their non-blended fits.…”

Section: The Search For Microlensing Around the Galactic Centermentioning

confidence: 99%

VVV Survey Microlensing Events in the Galactic Center Region

Navarro

Minniti

Ramos

2017

ApJL

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We search for microlensing events in the highly reddened areas surrounding the Galactic center using the near-IR observations with the VISTA Variables in the Vía Láctea Survey (VVV). We report the discovery of 182 new microlensing events, based on observations acquired between 2010 and 2015. We present the color-magnitude diagrams of the microlensing sources for the VVV tiles b332, b333, and b334, which were independently analyzed, and show good qualitative agreement among themselves. We detect an excess of microlensing events in the central tile b333 in comparison with the other two tiles, suggesting that the microlensing optical depth keeps rising all the way to the Galactic center. We derive the Einstein radius crossing time for all of the observed events. The observed event timescales range from t E = 5 to 200 days. The resulting timescale distribution shows a mean timescale of t 30.91 E á ñ = days for the complete sample (N = 182 events), and t 29.93 E á ñ = days if restricted only for the red clump (RC) giant sources (N = 96 RC events). There are 20 long timescale events (t 100 E  days) that suggest the presence of massive lenses (black holes) or disk-disk event. This work demonstrates that the VVV Survey is a powerful tool to detect intermediate/long timescale microlensing events in highly reddened areas, and it enables a number of future applications, from analyzing individual events to computing the statistics for the inner Galactic mass and kinematic distributions, in aid of future ground-and space-based experiments.

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Section: The Search For Microlensing Around the Galactic Centermentioning

confidence: 99%

VVV Survey Microlensing Events in the Galactic Center Region

Navarro

Minniti

Ramos

2017

ApJL

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“…The lensing magnification also makes strong lenses natural cosmic telescopes in resolving high-redshift sources. In addition, strong lens systems involving time-variant sources such as quasars measure the Hubble constant (Refsdal 1964), applications of gravitationally lensed quasars such as time delay cosmography (e.g., Coles 2008;Suyu et al 2010) can constrain the quasar luminosity function (Richards et al 2006) and dark energy (e.g. Kochanek 1996;Oguri et al 2012).…”

Section: Introductionmentioning

confidence: 99%

SDSS J1640+1932: a spectacular galaxy–quasar strong lens system

Wang

Shu

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present Canada-France-Hawaii Telescope (CFHT) MegaCam observations of a galaxy-quasar strong gravitational lens system, SDSS J1640+1932. This system, located at z=0.195 (foreground elliptical galaxy) and z=0.778 (background quasar), was first visually identified by us in the Sloan Digital Sky Survey (SDSS) database. Our CFHT imaging with an angular resolution of 0.7 ′′ clearly resolves 4 lensed images and a nearly complete Einstein ring. Modeling the system with a singular isothermal ellipsoid (SIE) total mass distribution, we find an Einstein radius of 2.49 ′′+0.063 −0.049 enclosing a inferred mass of 7.25 +0.37 −0.29 × 10 11 M ⊙ . The quasar and its host galaxy have been magnified by a factor of 23, and the time delay relative to the leading image is determined to be 23.4-25.2 days. These parameters vary minimally when our model is fitted to the g-, r-or i-band images.

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“…The phenomena resulting from the deflection of electromagnetic radiation in a gravitational field are referred to as gravitational lensing (GL) and an object causing a detectable deflection is known as a gravitational lens. The basic theory of GL was developed by Liebes [1], Refsdal [2] and Bourassa, Kantowski [3]. Detailed discussions on limit (SDL)), has received wide attention in the recent past.…”

Section: Introductionmentioning

confidence: 99%

Kerr-Sen dilaton-axion black hole lensing in the strong deflection limit

2007

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In the present work we study numerically quasi-equatorial lensing by the charged, stationary, axially-symmetric Kerr-Sen dilaton-axion black hole in the strong deflection limit. In this approximation we compute the magnification and the positions of the relativistic images. The most outstanding effect is that the Kerr-Sen black hole caustics drift away from the optical axis and shift in clockwise direction with respect to the Kerr caustics. The intersections of the critical curves on the equatorial plane as a function of the black hole angular momentum are found, and it is shown that they decrease with the increase of the parameter Q 2 /M . All of the lensing quantities are compared to particular cases as Schwarzschild, Kerr and Gibbons-Maeda black holes. I. INTRODUCTIONOne of the consequences of Einstein's General Theory of Relativity is that light rays are deflected by gravity. Although this discovery was made in the last century, the possibility that there could be such a deflection had been suspected much earlier, by Newton and Laplace, for the first time. The phenomena resulting from the deflection of electromagnetic radiation in a gravitational field are referred to as gravitational lensing (GL) and an object causing a detectable deflection is known as a gravitational lens. Nowadays, gravitational lensing is a rapidly developing area of research, and it has found applications ranging from the search of extrasolar planets and compact dark matter to the estimation of the values of the cosmological parameters [10]. In most of these cases it is possible to assume that the gravitational field is weak, hence the angle of deflection of the light in the field of a spherically symmetric body with mass M can be approximated by: that the present lens model could be able to distinguish observationally a black hole from naked singularity.The study of the gravitational lensing when light passes very close to a massive body, such as a black hole (a process also known as gravitational lensing in the strong deflection

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The Gravitational Lens Effect

Cited by 438 publications

References 0 publications

VVV Survey Microlensing Events in the Galactic Center Region

VVV Survey Microlensing Events in the Galactic Center Region

SDSS J1640+1932: a spectacular galaxy–quasar strong lens system

Kerr-Sen dilaton-axion black hole lensing in the strong deflection limit

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