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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 present a potential test of the origin of the $\gamma$-ray Galactic Centre Excess (GCE). We demonstrate how gravitational microlensing by stellar mass objects along the line of sight to the Galactic Bulge can distinguish between the…

High Energy Astrophysical Phenomena · Physics 2025-08-28 Nada Salama , Florian List , Geraint Lewis

Recent studies have demonstrated that detailed monitoring of gravitational microlensing events can reveal the presence of planets orbiting the microlensed source stars. With the potential of probing planets in the Galactic Bulge and…

Astrophysics · Physics 2009-11-06 Ceri E. Ashton , Geraint F. Lewis

We study the time variation of the apparent flux of cosmological point sources due to the transient weak lensing by dark matter microhaloes. Assuming a transverse motion of microhaloes with respect to our line of sight, we derive the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Sohrab Rahvar , Shant Baghram , Niayesh Afshordi

We study the microlensing of Non-Radially Pulsating (NRP) stars. Pulsations are formulated for stellar radius and temperature using spherical harmonic functions with different values of l,m. The characteristics of the microlensing light…

Solar and Stellar Astrophysics · Physics 2020-09-09 Sedighe Sajadian , Richard Ignace

Here we consider the influence of the microlensing on the spectrum of a lensed object taking into account that composite emission is coming from different regions arranged subsequently around the central source. We assumed that the lensed…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 Sasa Z. Simic , Luka C. Popovic , Predrag Jovanovic

With several detections, the technique of gravitational microlensing has proven useful for studying planets that orbit stars at Galactic distances, and it can even be applied to detect planets in neighbouring galaxies. So far, planet…

Astrophysics · Physics 2010-11-02 S. Rahvar , M. Dominik

In this article, we have investigated the possibility to distinguish between different galactic models through the microlensing parallax studies. We show that a systematic search for parallax effects can be done using the currently running…

Astrophysics · Physics 2007-05-23 S. Rahvar , M. Moniez , R. Ansari , O. Perdereau

In this talk I review some of the key questions that weak lensing observations of clusters can potentially answer, and sketch the progress that has been made to date in extracting quantitative estimates of masses and density profiles. A…

Astrophysics · Physics 2007-05-23 Nick Kaiser

Polarization is one of the fundamental natures of electromagnetic radiation. The detection of polarization or polarized photons from distant X-ray radiating systems (such as X-ray binaries (XBs), active galactic nuclei (AGN), pulsars, and…

High Energy Astrophysical Phenomena · Physics 2026-01-01 Arbind Pradhan , Sree Bhattacherjee , Biplob Sarkar

Inhomogeneities can influence the polarisation emerging from a synchrotron source. However, it is shown that the frequency distribution of circular polarisation is only marginally affected, although its magnitude may change substantially.…

High Energy Astrophysical Phenomena · Physics 2020-05-13 C. -I. Bjornsson

Gravitational lensing distorts the cosmic microwave background (CMB) temperature and polarization fields and encodes valuable information on distances and growth rates at intermediate redshifts into the lensed power spectra. The…

Astrophysics · Physics 2008-11-26 Kendrick M. Smith , Wayne Hu , Manoj Kaplinghat

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…

Extended source effects can be seen in gravitational lensing events when sources cross critical lines. Those events probe the stellar intensity profile and could be used to measure limb darkening coefficients to test stellar model…

Instrumentation and Methods for Astrophysics · Physics 2019-08-14 Hans J. Witt , F. Atrio-Barandela

We point out some advantages of making observations of extrasolar planets in linearly polarized (LP) light. Older cool stars have quite low levels (~ 10^-4 to 10^-5) of fractional LP, while extrasolar planets can have relatively high…

Astrophysics · Physics 2007-05-23 S. Saar , S. Seager

We study moderate gravitational lensing where a background galaxy is magnified substantially, but not multiply imaged, by an intervening galaxy. We focus on the case where both the lens and source are elliptical galaxies. The signatures of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 S. Mao , J. Wang , M. C. Smith

The presence or lack of eclipses in the X-ray lightcurves of ultraluminous X-ray sources (ULXs) can be directly linked to the accreting system geometry. In the case where the compact object is stellar mass and radiates isotropically, we…

High Energy Astrophysical Phenomena · Physics 2016-08-03 Matthew Middleton , Andrew King

Extremely strong magnetic fields change the vacuum index of refraction. This induces a lensing effect that is not unlike the lensing phenomenon in strong gravitational fields. The main difference between the two is the polarization…

Astrophysics · Physics 2009-10-31 Nir J. Shaviv , Jeremy S. Heyl , Yoram Lithwick

We derive expressions, in terms of "polar shapelets", for the image distortion operations associated with weak gravitational lensing. Shear causes galaxy shapes to become elongated, and is sensitive to the second derivative of the projected…

Astrophysics · Physics 2008-11-26 Richard Massey , Barnaby Rowe , Alexandre Refregier , David J. Bacon , Joel Berge

Paczy\'nski (1986) suggested that ``dark" objects in the halo of our Galaxy could enhance the luminosity of foreground stars, acting as gravitational microlenses. Such events has been recently reported by different collaborations. We assume…

Astrophysics · Physics 2007-05-23 Sergio Campana