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We study the linear polarization from the accretion disk around a class of static traversable wormholes. Applying the simplified model of a magnetized fluid ring orbiting in the equatorial plane, we search for characteristic signatures,…

General Relativity and Quantum Cosmology · Physics 2022-06-22 Valentin Delijski , Galin Gyulchev , Petya Nedkova , Stoytcho Yazadjiev

The potential of the gravitational microlensing inside our Galaxy for testing the Einstein formula for the gravitational light deflection is discussed. For this purpose, the lens mapping is modified by introducing parameter eps, which…

General Relativity and Quantum Cosmology · Physics 2020-12-22 A. N. Alexandrov , V. M. Sliusar , V. I. Zhdanov

We model the supermassive dark object $M87^*$ as a Schwarzschild lens and study the variations in tangential, radial, and total (the product of tangential and radial) magnifications of images (primary, secondary, and relativistic) against…

General Relativity and Quantum Cosmology · Physics 2022-09-23 K. S. Virbhadra

A description of the light curves of microlensed Type Ia supernovae (SNe Ia) as extended and expanding sources is presented. We give examples of what microlensing by stellar-mass Chang-Refsdal lenses can do to a small percentage of…

Astrophysics · Physics 2007-05-23 H. Bagherpour , B. Chen , R. Kantowski , D. Branch , D. Richardson

We examine the possibility of observing gravitational lensing in the weak deflection regime by the supermassive black hole in the center of the galaxy M31. This black hole is significantly more massive than the black hole in the center of…

Astrophysics · Physics 2009-06-23 V. Bozza , S. Calchi Novati , L. Mancini

Microlensing of stars, e.g. in the Galactic bulge and Andromeda galaxy (M31), is among the most robust, powerful method to constrain primordial black holes (PBHs) that are a viable candidate of dark matter. If PBHs are in the mass range…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-31 Sunao Sugiyama , Toshiki Kurita , Masahiro Takada

The gravitational lensing effects in the weak gravitational field by exotic lenses have been investigated intensively to find nonluminous exotic objects. Gravitational lensing based on 1/r^n fall-off metric, as a one-parameter model that…

General Relativity and Quantum Cosmology · Physics 2014-09-25 Naoki Tsukamoto , Takao Kitamura , Koki Nakajima , Hideki Asada

Gravitational lens models with negative convergence(surface mass density projected onto the lens plane) inspired by modified gravity theories, exotic matter and energy have been recently discussed in such a way that a static and…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Koji Izumi , Chisaki Hagiwara , Koki Nakajima , Takao Kitamura , Hideki Asada

We consider a class of stationary and axisymmetric wormhole spacetimes that is closely related to, but not identical with, the class of Teo wormholes. We fix a point $p$ (observation event) and a timelike curve $\gamma$ (worldline of a…

General Relativity and Quantum Cosmology · Physics 2022-01-11 Mourad Halla , Volker Perlick

A fraction of Galactic stars have compact companions which could be white dwarfs (WDs), neutron stars (NSs) or stellar-mass black holes (SBHs). In a detached and edge-on binary system including a main-sequence star and a compact object…

Solar and Stellar Astrophysics · Physics 2024-09-20 Sedighe Sajadian , Niayesh Afshordi

We investigate gravitational microlensing signals produced by a spatially extended object transiting in front of a finite-sized source star. The most interesting features arise for lens and source sizes comparable to the Einstein radius of…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 Djuna Croon , David McKeen , Nirmal Raj , Zihui Wang

Gravitational microlensing within the Galaxy offers the prospect of probing the details of distant stellar sources, as well as revealing the distribution of compact (and potentially non-luminous) masses along the line-of-sight. Recently, it…

Astrophysics of Galaxies · Physics 2020-01-08 Geraint F. Lewis , Peter Tuthill

In quasars which are lensed by galaxies, the point-like images sometimes show sharp and uncorrelated brightness variations (microlensing). These brightness changes are associated with the innermost region of the quasar passing through a…

High Energy Astrophysical Phenomena · Physics 2016-04-08 Mihai Tomozeiu , Irshad Mohammed , Manuel Rabold , Prasenjit Saha , Joachim Wambsganss

It is concluded in the literature that Ellis wormhole is unstable under small perturbations and would decay either to the Schwarzschild black hole or expand away to infinity. While this deterministic conclusion of instability is correct, we…

General Relativity and Quantum Cosmology · Physics 2016-06-22 Kamal K. Nandi , Alexander A. Potapov , Ramil Izmailov , Amarjit Tamang , James C. Evans

We investigate the distortions due to this shear in the microlensing light curves and in the astrometric microlensing centroid shift trajectories. As expected, the light curve deviation increases as the shear increases and the impact…

Astrophysics · Physics 2009-11-13 Yoon-Hyun Ryu , Myeong-Gu Park

It is well known that the sum of signed magnifications is invariant for mass lens systems. In this paper, we discuss the signed magnification sums of general spherical lens models including the singular isothermal sphere, the Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2013-01-15 Naoki Tsukamoto , Tomohiro Harada

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

We present here an analysis of the light curves of 5.3 million stars in the Small Magellanic Cloud observed by EROS (Exp\'erience de Recherche d'Objets Sombres). One star exhibits a variation that is best interpreted as due to gravitational…

Astrophysics · Physics 2007-05-23 EROS collaboration , N. Palanque-Delabrouille et al

We present the analysis of the microlensing event KMT-2018-BLG-1743. The light curve of the event, with a peak magnification $A_{\rm peak}\sim 800$, exhibits two anomaly features, one around the peak and the other on the falling side of the…