相关论文: Microlensing by Compact Objects associated to Gas …

Microlensing searches aim to detect compact halo dark matter via its gravitational lensing effect on stars within the Large Magellanic Cloud. The most recent results have led to the claim that roughly one fifth of the galactic halo dark…

Massive Compact objects in the halo, known as MACHOs, have been postulated as the origin of a substantial fraction of `dark matter' known to exist in the haloes of galaxies$^{1,2}$. Paczy\'nski$^3$ has suggested that it might possible to…

Gravitational microlensing of gravitational waves (GWs) opens up the exciting possibility of studying the spacetime geometry around the lens. In this work, we investigate the prospects of constraining the `charged' hair of a charged…

We discuss a possible method for detection of dark companions of galactic objects of stellar mass. Such binary systems are likely to occur in the galactic disk and possibly also in the halo. The high incidence of binary and…

Gravitational lensing in clusters of galaxies is an efficient tool to probe the mass distribution of galaxies and clusters, high redshift objects thanks to the gravitational amplification, and the geometry of the universe. We review some…

We present results from a search for gravitational microlensing of stars in the Large Magellanic Cloud by low mass objects in the Galactic Halo. The search uses the CCD light curves of about 82,000 stars with up to 46 measurements per night…

Gravitational lensing describes the bending of the trajectories of light and gravitational waves due to the gravitational potential of a massive object. Strong lensing by galaxies can create multiple images with different overall…

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…

We study the influence of a cosmological population of dense gas clouds on distant sources, with emphasis on quasar optical variability. In addition to gravitational lensing such clouds affect flux measurements via refraction in the neutral…

One of the most important problems in astrophysics concerns the nature of the dark matter in galactic halos, whose presence is implied mainly by the observed flat rotation curves in spiral galaxies. In the framework of a baryonic scenario…

The population of solitary compact objects in the Galaxy is very diffcult to investigate. In this paper we analyze the possibility of using microlensing searches to detect and to analyze the properties of the solitary black holes and…

Microlensing has established itself as a powerful new method for the detection of baryonic dark matter in the Galaxy. The theory of microlensing is sketched and its similarity with the optical effect of twinkling is explained. The bulk of…

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…

Gravitational lensing of background compact objects like active galactic nuclei and quasars, by extended intermediate mass lenses such as globular clusters and and dark matter clumps with masses 10^5 - 10^8 M_sun, is considered. It is shown…

Experiments are looking for diffuse brown dwarfs in the dark galactic halo through the gravitational lens effect. If brown dwarfs are clumped in dark clusters, the event rate is not changed, but events are spatially clustered, and stars…

The measurements of the possible gravitational microlensing events are analysed with a simple yet accurate disc--halo model of the Milky Way Galaxy. This comprises a luminous exponential disc embedded in a flattened dark matter halo with…

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…

One of the most fascinating predictions of the theory of general relativity is the effect of gravitational lensing, the bending of light in close proximity to massive stellar objects. Recently, artificial optical materials have been…

Gravitational lensing is brightening of background objects due to deflection of light by foreground sources. Rich clusters of galaxies are very effective lenses because they are centrally concentrated. Such natural Gravitational Telescopes…

We study the gravitational lensing properties of a massive object in a dark matter halo, concentrating on the critical curves and caustics of the combined lens. We model the system in the simplest approximation by a point mass embedded in a…