相关论文: Microlensing and the Stellar Mass Function
Gravitational lensing directly measures mass density fluctuations along the lines of sight to very distant objects. No assumptions need to be made concerning bias, the ratio of fluctuations in galaxy density to mass density. Hence, lensing…
Four ongoing microlensing experiments have produced important new results but also big puzzles, the major one being that the expected classes of lenses cannot account for the observed distribution of time scales. I discuss future…
Gravitational Microlensing has been used as a powerful tool for astrophysical studies and exoplanet detections. In the gravitational microlensing, we have two images with negative and positive parities. The negative-parity image is a…
If a light-emitting star is responsible for a gravitational microlensing event, the lens can be characterized by analyzing the blended light from the lens. In this paper, we investigate the feasibility of characterizing lenses by using this…
Since the first microlensing planet discovery in 2003, more than 200 planets have been detected with gravitational microlensing, in addition to several free-floating planet and black hole candidates. In this chapter the microlensing theory…
Microlensing is the only known direct method to measure the masses of stars that lack visible companions. In terms of microlensing observables, the mass is given by M=(c^2/4G)\tilde r_E \theta_E and so requires the measurement of both the…
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…
We introduce a new method of searching for and characterizing extra-solar planets. We show that by monitoring the center-of-light motion of microlensing alerts using the next generation of high precision astrometric instruments the…
Galactic Exoplanet Survey Telescope (GEST) was proposed for a discovery mission to search for microlensing terrestrial planets toward the Galactic bulge and also Kuiper Belt Objects (KBOs) that are believed to hold vital information of the…
Microlensing by stars within distant galaxies acting as strong gravitational lenses of multiply-imaged quasars, provides a unique and direct measurement of the internal structure of the lensed quasar on nano-arcsecond scales. The…
Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this…
We present a new approach in the study of the Initial Mass function (IMF) in external galaxies based on quasar microlensing observations. We use measurements of quasar microlensing magnifications in 24 lensed quasars to estimate the average…
We measure the stellar mass surface densities of early type galaxies by observing the micro-lensing of macro-lensed quasars caused by individual stars, including stellar remnants, brown dwarfs and red dwarfs too faint to produce photometric…
We propose a new technique to directly measure the shapes of dark matter halos of galaxies using weak gravitational lensing. Extending the standard galaxy-galaxy lensing method, we show that the shape parameters of the mass distribution of…
Je presente une revue des microlentilles gravitationnelles en quatre lecons. Dans un premier temps, je discute la theorie des microlentilles dans le contexte general des lentilles, en incluant les effets de la taille finie des sources, de…
Microlensing events can be used to directly measure the masses of single field stars to a precision of $\sim$1-10\%. The majority of direct mass measurements for stellar and sub-stellar objects typically only come from observations of…
The study of extra-solar planetary systems has emerged as a new discipline of observational astronomy in the past few years with the discovery of a number of extra-solar planets. The properties of most of these extra-solar planets were not…
We study the benefits of polarimetry observations of microlensing events to detect and characterize circumstellar disks around the microlensed stars located at the Galactic bulge. These disks which are unresolvable from their host stars…
Galactic bulges are central to understanding galaxy formation and evolution. Here we report on recent studies using micro-lensing events to obtain spectra of high resolution and moderately high signal-to-noise ratios of dwarf stars in the…
Gravitational microlensing of planetary-mass objects (or "nanolensing", as it has been termed) can be used to probe the distribution of mass in a galaxy that is acting as a gravitational lens. Microlensing and nanolensing light curve…