1,721,039 research outputs found
Exoplanet Searches in the Habitable Zone with Gravitational Microlensing
No full textThere are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing, etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potential of detecting Earth-like planets at distances about a few astronomical units from their host stars. Here we emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models. In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source
Monte Carlo analysis of MEGA microlensing events towards M 31
No full textWe perform an analytical study and a Monte Carlo (MC) analysis of the main features for microlensing events in pixel lensing observations towards M 31. Our main aim is to investigate the lens nature and location of the 14 candidate events found by the MEGA collaboration. Assuming a reference model for the mass distribution in M 31 and the standard model for our galaxy, we estimate the MACHO-to-self lensing probability and the event time duration towards M 31. Reproducing the MEGA observing conditions, as a result we get the MC event number density distribution as a function of the event full-width half-maximum duration t1/2 and the magnitude at maximum R_max. For a MACHO mass of 0.5~Msun we find typical values of t1/2 ≃ 20 day and Rmax ≃ 22, for both MACHO-lensing and self-lensing events occurring beyond about 10 arcmin from the M 31 center. A comparison of the observed features (t1/2 and Rmax) with our MC results shows that for a MACHO mass > 0.1~Msun the four innermost MEGA events are most likely self-lensing events, whereas the six outermost events must be genuine MACHO-lensing events
Exoplanet searches with gravitational microlensing
Full text linkDifferent regimes of gravitational lensing depend on
lens masses and roughly correspond to angular dis-
tance between images. If a gravitational lens has a
typical stellar mass, this regime is named microlens-
ing because the typical angular distance between im-
ages is about microarcseconds in the case for sources
and lenses at cosmological distances. The angular dis-
tance depends on as a squared root of lens mass and
therefore, for Earth-like planet mass lens (10−6 M ),
such a regime is called nanolensing. So, one can
name searches for exoplanets with gravitational lens
method as gravitational nanolensing. There are differ-
ent methods for finding exoplanets such as radial spec-
tral shifts, astrometrical measurements, transits, tim-
ing etc. Gravitational microlensing (including pixel-
lensing) is among the most promising techniques with
the potentiality of detecting Earth-like planets at dis-
tances about a few astronomical units from their host
stars
Exoplanet Searches with Gravitational Microlensing
No full textThere are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potentiality of detecting Earth-like planets at distances about a few astronomical units from their host star. We emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models. In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source
Exoplanetary searches with gravitational microlensing: Polarization issues
Full text linkThere are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potentiality of detecting Earth-like planets at distances about a few astronomical units from their host star or near the so-called snow line with a temperature in the range 0-100 °C on a solid surface of an exoplanet. We emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models. In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source
Detection of exoplanets in M31 with pixel-lensing: the Event PA-99-N2 Case
No full textWe show that exoplanets in the M31 galaxy may be detected with the pixel-lensing method by using telescopes making high cadence observations of an ongoing microlensing event
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