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Related papers: Microlensing by Stellar Black Holes Around Sgr A*

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The detection of old neutron stars and black holes in isolation is one of the cornerstones of compact object astrophysics. Microlensing surveys may help on this purpose since the lensing mechanism is independent of the emission properties…

High Energy Astrophysical Phenomena · Physics 2015-06-03 N. Sartore , A. Treves

Microlensing observations toward globular clusters could be very useful to probe their low mass star and brown dwarf content. Using the large set of microlensing events detected so far toward the Galactic centre we investigated whether for…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-23 Philippe Jetzer

We show that a possible astrophysical experiment, detection of lensed images of stars orbiting close to Sgr A*, can provide insight into the form of the metric around a black hole. We model Sgr A* as a black hole and add in a…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Amitai Y. Bin-Nun

Gravitational microlensing constraints on non-standard compact objects are conventionally derived assuming lenses trace the dark matter halo with velocities following a Maxwell-Boltzmann distribution centered around $10^{-3}c$. However, a…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-06 Manish Tamta , Nirmal Raj , Himanshu Verma

The question of the origin of the gas supplying the accretion process is pertinent especially in the context of enhanced activity of Galactic Center during the past few hundred years, seen now as echo from the surrounding molecular clouds,…

Astrophysics of Galaxies · Physics 2015-06-12 Bozena Czerny , Vladimir Karas , Devaky Kunneriath , Tapas K. Das

Our knowledge of the birth mass function of neutron stars and black holes is based on observations of binary systems but the binary evolution likely affects the final mass of the compact object. Gravitational microlensing allows us to…

Solar and Stellar Astrophysics · Physics 2021-07-30 P. Mroz , A. Udalski , L. Wyrzykowski , J. Skowron , R. Poleski , M. Szymanski , I. Soszynski , K. Ulaczyk

We present the results of 16 years of monitoring stellar orbits around the massive black hole in center of the Milky Way using high resolution NIR techniques. This work refines our previous analysis mainly by greatly improving the…

Astrophysics · Physics 2011-02-11 S. Gillessen , F. Eisenhauer , S. Trippe , T. Alexander , R. Genzel , F. Martins , T. Ott

The Galactic center provides a unique astrophysical laboratory for us to study various astrophysical processes. In this paper, we review and outline the latest results from observations of Sgr~A$^*$ in terms of source structure and…

Astrophysics · Physics 2007-05-23 Feng Yuan , Jun-Hui Zhao

In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based…

We calculate the optical depth and the number of events due to gravitational microlensing towards the Galactic bulge, the spiral arm directions $\gamma$ Scutum, $\beta$ Scutum, $\gamma$ Normae, $\vartheta$ Muscae and some dwarf galaxies in…

Astrophysics · Physics 2007-05-23 Lukas Grenacher , Philippe Jetzer , Marcus Strässle , Francesco De Paolis

Observations of the Sgr A* region in the galactic center confirm the presence of a large amount of matter in a small volume, leading to the consensus that a black hole exists there. However, dynamical observations cannot rule out the…

General Relativity and Quantum Cosmology · Physics 2013-01-09 Amitai Y. Bin-Nun

Observations of the galactic center revealed a population of young massive stars within 0.4 pc from Sgr A* -- the presumed location of a supermassive black hole. The origin of these stars is a puzzle as their formation in citu should be…

Astrophysics · Physics 2010-04-06 Yuri Levin , Andrei M. Beloborodov

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

This review outlines the observations that now provide an overwhelming scientific case that the center of our Milky Way Galaxy harbors a supermassive black hole. Observations at infrared wavelength trace stars that orbit about a common…

Astrophysics · Physics 2009-07-22 Mark J. Reid

Gravitational lensing assists in the detection of quasar hosts by amplifying and distorting the host light away from the unresolved quasar core images. We present the results of HST observations of 30 quasar hosts at redshifts 1 < z < 4.5.…

We present the Catalog of microlensing events detected toward the Galactic bulge in three observing seasons, 1997--1999, during the OGLE-II microlensing survey. The search for microlensing events was performed using a database of about…

Astrophysics · Physics 2007-05-23 A. Udalski , K. Zebrun , M. Szymanski , M. Kubiak , G. Pietrzynski , I. Soszynski , P. Wozniak

Over the past decade, microlensing has developed into a powerful tool to study stellar astrophysics, especially stellar atmospheres, stellar masses, and binarity. I review this progress. Stellar atmospheres can be probed whenever the source…

Astrophysics · Physics 2016-08-30 Andrew Gould

While microlensing is very rare, occurring on average once per million stars observed, current and near-future surveys are coming online with the capability of providing photometry of almost the entire visible sky to depths up to R ~ 22 mag…

Instrumentation and Methods for Astrophysics · Physics 2020-04-30 D. Godines , E. Bachelet , G. Narayan , R. A. Street

In the near future, wide field surveys will discover 1000's of new strongly lensed quasars, and these will be monitored with unprecedented cadence by the Legacy Survey of Space and Time (LSST). Many of these will undergo caustic-crossing…

Astrophysics of Galaxies · Physics 2024-07-16 Henry Best , Joshua Fagin , Georgios Vernardos , Matthew O'Dowd
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