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More reliable constraints on the microlensing optical depth comes from a better understanding of the Galactic model. Based on well-constrained Galactic bulge and disk models constructed from survey observations, such as, HST, 2MASS, and…

Astrophysics · Physics 2009-11-13 Yoon-Hyun Ryu , Heon-Young Chang , Myeong-Gu Park , Ki-Won Lee

EAGLE is the multi-object, spatially-resolved, near-IR spectrograph instrument concept for the E-ELT, relying on a distributed Adaptive Optics, so-called Multi Object Adaptive Optics. This paper presents the results of a phase A study.…

We have observed the gravitational lens system Q2237+0305 from the Maidanak Observatory over the period from August 2002 to November 2003. Here we report the results of our observations. We implemented a two-stage technique that has been…

Microlensing is a powerful and unique technique to probe isolated objects in the Galaxy. To study the characteristics of these interesting objects based on the microlensing method, measurement of the microlens parallax is required to…

We analyze the photometric data obtained by PLANET and OGLE on the caustic-crossing binary-lens microlensing event OGLE-2002-BLG-069. Thanks to the excellent photometric and spectroscopic coverage of the event, we are able to constrain the…

We measure the astrometric shifts of the light centroids for the microlensing events in the OGLE-1 database. Of the 15 consistently detected events, 7 had significant shifts which we were able to measure with a fair degree of confidence.…

Astrophysics · Physics 2007-05-23 David M. Goldberg , Przemyslaw Wozniak

One of the main objectives of the Cosmic Lens All-Sky Survey (CLASS) collaboration has been to find gravitational lens (GL) systems at radio wavelengths that are suitable for the determination of time delays between image pairs. The survey…

Astrophysics · Physics 2009-11-06 L. V. E. Koopmans , the CLASS collaboration

(abridged) Gravitationally lensed quasars can be used as powerful cosmological and astrophysical probes. We can (i) infer the Hubble constant based on the time-delay technique, (ii) unveil substructures along the l.o.s. toward distant…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-05 D. Sluse , V. Chantry , P. Magain , F. Courbin , G. Meylan

We explore three different methods based on weak lensing to extract cosmological constraints from the large-scale structure. In the first approach (method I), small-scale galaxy lensing measurements of their halo mass provide a constraint…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jaiyul Yoo , Uros Seljak

Strong gravitational lensing of active galactic nuclei (AGN) enables measurements of cosmological parameters through time-delay cosmography (TDC). With data from the upcoming LSST survey, we anticipate using a sample of O(1000) lensed AGN…

We have identified seven (field) elliptical galaxies acting as strong gravitational lenses and have used them to measure cosmological parameters. To find the most likely value for Omega_m (= Omega_matter) and Lambda, we have used the…

Astrophysics · Physics 2009-10-28 Myungshin Im , Richard E. Griffiths , Kavan U. Ratnatunga

Following the suggestion of Gould and Depoy (1998) we investigate the feasibility of studying the brightest microlensing events towards the Galactic bulge using a small aperture (~10 cm) telescope. We used one of the HAT telescopes to…

Astrophysics of Galaxies · Physics 2009-05-01 D. M. Nataf , K. Z. Stanek , G. A. Bakos

Galaxy-scale strong gravitational lenses with measured stellar velocity dispersions allow a test of the weak-field metric on kiloparsec scales and a geometric measurement of the cosmological distance-redshift relation, provided that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Josiah Schwab , Adam S. Bolton , Saul A. Rappaport

We examined light curves of 1138 stars brighter than 18.0 mag in the $I$ band and less than a mean magnitude error of 0.1 mag in the $V$ band from the OGLE-III eclipsing binary catalogue, and found 90 new binary systems exhibiting apsidal…

Solar and Stellar Astrophysics · Physics 2025-03-25 K. Hong , J. W. Lee , S. -L. Kim , J. -R. Koo , C. -U. Lee

Optical photometry is presented for the quadruple gravitational lens PG1115+080. A preliminary reduction of data taken from November 1995 to June 1996 gives component ``C'' leading component ``B'' by 23.7+/-3.4 days and components ``A1''…

We describe a new method for measuring galaxy magnification due to weak gravitational lensing. Our method makes use of a tight scaling relation between galaxy properties that are modified by gravitational lensing, such as apparent size, and…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-07 Eric M. Huff , Genevieve J. Graves

After an introduction on phenomena due to spin and mass-energy currents on clocks and photons, we review the 1995-2001 measurements of the gravitomagnetic field of Earth and Lense-Thirring effect obtained by analyzing the orbits of the two…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ignazio Ciufolini

The laws of geometric optics and their corrections are derived for scalar, electromagnetic, and gravitational waves propagating in generic curved spacetimes. Local peeling-type results are obtained, where different components of…

General Relativity and Quantum Cosmology · Physics 2019-01-08 Abraham I. Harte

We have monitored 8.6 million stars in the Large Magellanic Cloud for 1.1 years and have found 3 events consistent with gravitational microlensing. We place strong constraints on the Galactic halo content in the form of compact lensing…

We present the largest collection of delta Scuti-type stars in the Milky Way. Together with the recently published OGLE collection of delta Sct variables in the inner Galactic bulge, our sample consists of 24 488 objects distributed along…

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