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Recent discussion of the effects of finite source size on high magnification microlensing events due to MACHOs motivates a study into the feasibility of observing such effects and extracting the source radius. Simulated observations are…

Astrophysics · Physics 2009-10-28 Eric Peng

We consider the dispersion on the supernova distance-redshift relation due to peculiar velocities and gravitational lensing, and the sensitivity of these effects to the amplitude of the matter power spectrum. We use the MeMo lensing…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Edward Macaulay , Tamara M. Davis , Dario Scovacricchi , David Bacon , Thomas E. Collett , Robert C. Nichol

Precise lens modeling is a critical step in time delay studies of multiply imaged quasars, which are key for measuring some important cosmological parameters (specially $H_0$). However, lens models (in particular those semi-automatically…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-16 E. Mediavilla , J. Jiménez-Vicente , V. Motta

In this paper we explore a quantitative and efficient method to constrain the halo properties of distant galaxy populations through ``galaxy--galaxy" lensing and show that the mean masses and sizes of halos can be estimated accurately,…

Astrophysics · Physics 2009-10-28 Peter Schneider , Hans-Walter Rix

In microlensing of a Galactic star by a brown dwarf or other compact object, the amplified image really consists of two unresolved images with slightly different light-travel times. The difference (of order a microsecond) is GM/c^3 times a…

Instrumentation and Methods for Astrophysics · Physics 2019-05-08 Prasenjit Saha

To overcome the high optical extinction, near-infrared observations are needed for probing the microlensing events toward the Galactic center. The 2015-2019 UKIRT microlensing survey toward the Galactic center is the first dedicated…

Earth and Planetary Astrophysics · Physics 2023-09-06 Yongxin Wen , Weicheng Zang , Bo Ma

The light received by source stars in microlensing events may be significantly polarized if both an efficient photon scattering mechanism is active in the source stellar atmosphere and a differential magnification is therein induced by the…

Solar and Stellar Astrophysics · Physics 2015-06-17 G. Ingrosso , F. De Paolis , A. A. Nucita , F. Strafella , S. Calchi Novati , Ph. Jetzer , G. Liuzzi , A. Zakharov

We determine the microlensing event rate distribution, $\Gamma(t_{E})$, that is properly normalized by the first year MACHO group observations (Alcock et al. 1997). By comparing the determined $\Gamma(t_{E})$ with various MF models of lens…

Astrophysics · Physics 2007-05-23 Cheongho Han , Seunghun Lee

We conduct the first microlensing simulation in the context of planet formation model. The planet population is taken from the Ida & Lin core accretion model for $0.3M_\odot$ stars. With $6690$ microlensing events, we find for a simplified…

Earth and Planetary Astrophysics · Physics 2015-06-19 Wei Zhu , Matthew Penny , Shude Mao , Andrew Gould , Rieul Gendron

Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several…

When a microlensing light curve is contaminated by blended light from unresolved stars near the line of sight to the lensed star, the light curve shape and corresponding parameterization for the event will differ from the values expected…

Astrophysics · Physics 2009-10-31 Cheongho Han

When there is more than one source of light along the line of sight to a gravitationally lensed object, the characteristics of the observed light curve are influenced by the presence of the light that is not lensed. In this paper we develop…

Astrophysics · Physics 2009-10-28 R. DiStefano , A. A. Esin

Pixel lensing is gravitational microlensing of unresolved stars. The main target explored up to now has been the nearby galaxy of Andromeda, M31. The scientific issues of interest are the search for dark matter in form of compact halo…

Astrophysics of Galaxies · Physics 2010-08-24 S. Calchi Novati

Hundreds of gravitational microlensing events have now been detected towards the Galactic bulge, with many more to come. The detection of fine structure in these events has been theorized to be an excellent way to discover extra-solar…

Astrophysics · Physics 2010-04-06 Kim Griest , Neda Safizadeh

In recent years various models for the Galactic distribution of massive compact halo objects (MACHOs) have been proposed for the interpretation of microlensing toward the Large Magellanic Cloud (LMC). A direct way to fit the best model is…

Astrophysics · Physics 2009-11-10 Sohrab Rahvar , Sima Ghassemi

Gravitationally lensed extragalactic sources are often subject to statistical microlensing by stars in the galaxy or cluster lens. Accurate models of the flux statistics are required for inferring source and lens properties from flux…

Astrophysics of Galaxies · Physics 2021-04-27 Liang Dai , Massimo Pascale

During microlensing events with a small impact parameter, the amplification of the source flux is sensitive to the surface brightness distribution of the source star. Such events provide a means for studying the surface structure of target…

Astrophysics · Physics 2009-10-31 David Heyrovsky , Dimitar Sasselov

We propose and evaluate the feasibility of a new strategy to search for planets via microlensing observations. This new strategy is designed to detect planets in "wide" orbits, i.e., with orbital separation, a, greater than ~1.5 R_E.…

Astrophysics · Physics 2007-05-23 Rosanne Di Stefano , Richard A. Scalzo

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…

Astrophysics · Physics 2009-10-31 Tal Alexander , Amiel Sternberg

Previous calculations of the rates and optical depths due to microlensing only considered resolved stars. However, if a faint unresolved star lens is close enough to a resolved star, the event will be seen by the microlensing experiments…

Astrophysics · Physics 2007-05-23 C. Alard