Related papers: Resolving Microlensing Events with Triggered VLBI

The longest microlensing events provide enough information to estimate the mass and distance of the lens. Among hundreds of millions of stars which were monitored for many years by the OGLE project we selected those with clear parallax…

Microlensing events provide a unique way to detect and measure the masses of isolated, non-luminous objects, particularly dark stellar remnants. Under certain conditions, it is possible to measure the mass of these objects using photometry…

We present an analysis of the longest timescale microlensing events discovered by the MACHO Collaboration during a 7 year survey of the Galactic bulge. We find 6 events that exhibit very strong microlensing parallax signals due, in part, to…

Until now, the detailed interpretation of the observed microlensing events has suffered from the fact that the physical parameters of the phenomenon cannot be uniquely determined from the available astronomical measurements, i.e. the…

We investigate microlensing amplification of faint stars in the dense stellar cluster in the Galactic Center (GC) by the super-massive black hole (BH). Such events would appear very close to the position of the radio source SgrA*, which is…

In this paper we investigate the properties of astrometric microlensing of distant radio sources (QSOs and radio galaxies) due to MACHOs, and discuss their implications for VERA (VLBI Exploration of Radio Astrometry). First we show that in…

We report on the first results from a large-scale observing campaign aiming to use astrometric microlensing to detect and place limits on the mass of single objects, including stellar remnants. We used the Hubble Space Telescope to monitor…

Observations of caustic-crossing galaxies at redshift $0.7<z<1$ show a wealth of transient events. Most of them are believed to be microlensing events of highly magnified stars. Earlier work predicted such events should be common near the…

Microlensing experiments today have a tantalizing result; they have detected an excess of microlensing events beyond what is expected from known stellar populations. These events could be due to a possible form of Halo dark matter. However,…

We investigate properties of astrometric microlensing of distant sources (such as QSOs and radio galaxies) caused by stars in the Galaxy, mainly focusing on application to the VERA (VLBI Exploration of Radio Astrometry) project. Assuming…

The effect of stars on the lensing properties of the supermassive black hole in the Galactic Center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around SgrA* increases by factors of a…

This paper presents an investigation into the gravitational microlensing of quasars by stars and stellar remnants in the Milky Way. We present predictions for the all-sky microlensing optical depth, time-scale distributions and event rates…

Interferometric observations of microlensing events have the potential to provide unique constraints on the physical properties of the lensing systems. In this work, we first present a formalism that closely combines interferometric and…

Microlensing searches toward the inner galaxy $(|l|,|b|\leq 22.\hskip-2pt'5)$ have several major advantages. First, the event rate is strongly dominated by bulge-bulge lensing events where both the source and lens lie in the bulge. Second,…

By monitoring $10^6$ quasars one could search for lensing by stars and Massive Compact Halo Objects (Machos) out to redshifts $z\sim 4$. If Machos have a present cosmological density $\Omega_{L,0}=1\%$, then the expected event rate is…

We describe the results of a search for microlensing events affecting stars in the outer bulge and inner disk of M31, due both to masses in M31 and the Galaxy. These observations, from 1994 and 1995 on the Vatican Advanced Technology…

The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the…

Though stellar-mass black holes (BHs) are likely abundant in the Milky Way (N=10^8-10^9), only ~20 have been detected to date, all in accreting binary systems (Casares 2006). Gravitational microlensing is a proposed technique to search for…

Gravitational microlensing is a robust tool to detect and directly measure the abundance and mass of any kind of compact objects, either in our galaxy or in the extragalatic domain. On basis to generic, broadly applicable arguments, it is…

We present measurements of the microlensing optical depth and event rate toward the Galactic Bulge based on two years of the MOA-II survey. This sample contains ~1000 microlensing events, with an Einstein Radius crossing time of t_E < 200…