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In the self--lensing framework, we estimate the modal values of the mass of the gravitational lenses found by the MACHO collaboration towards the Large Magellanic Cloud (LMC). Our results suggest that only the events located near the center…

天体物理学 · 物理学 2011-10-18 L. Mancini , S. Calchi Novati , Ph. Jetzer , G. Scarpetta

We investigate how observations of strong lensing can be used to infer cosmological parameters, in particular the equation of state of dark energy. We focus on the growth of the critical lines of lensing clusters with the source redshift as…

宇宙学与河外天体物理 · 物理学 2012-04-03 Britta Zieser , Matthias Bartelmann

We determine the geometrical and viewing angle parameters of the Large Magellanic Cloud (LMC) using the Leavitt law based on a sample of more than $3500$ common classical Cepheids (FU and FO) in optical ($V,I$), near-infrared ($JHK_{s}$)…

星系天体物理 · 物理学 2018-05-16 Sukanta Deb , Chow-Choong Ngeow , Shashi M. Kanbur , Harinder P. Singh , Daniel Wysocki , Subhash Kumar

Variable stars with well-calibrated period-luminosity relationships provide accurate distance measurements to nearby galaxies and are therefore a vital tool for cosmology and astrophysics. While these measurements typically rely on samples…

天体物理仪器与方法 · 物理学 2019-04-09 Markus Michael Rau , Sergey E. Koposov , Hy Trac , Rachel Mandelbaum

We present the first part of a new catalog of variable stars (OIII-CVS) compiled from the data collected in the course of the third phase of the Optical Gravitational Lensing Experiment (OGLE-III). In this paper we describe the catalog of…

We present a method for solving the lightcurve of an eclipsing binary system which contains a Cepheid variable as one of its components as well as the solutions for three eclipsing Cepheids in the Large Magellanic Cloud (LMC). A geometric…

We present results from a search for gravitational microlensing of stars in the Large Magellanic Cloud by low mass objects in the Galactic Halo. The search uses the CCD light curves of about 82,000 stars with up to 46 measurements per night…

We explore the complementarity of weak lensing and galaxy peculiar velocity measurements to better constrain modifications to General Relativity. We find no evidence for deviations from GR on cosmological scales from a combination of…

宇宙学与河外天体物理 · 物理学 2012-10-26 Yong-Seon Song , Gong-Bo Zhao , David Bacon , Kazuya Koyama , Robert C Nichol , Levon Pogosian

The unknown nature of dark energy motivates continued cosmological tests of large-scale gravitational physics. We present a new consistency check based on the relative amplitude of non-relativistic galaxy peculiar motions, measured via…

Non-standard fields are assumed to be responsible for phenomena attributed to dark energy and dark matter. Being coupled to ordinary matter, these fields modify the masses and/or charges of the elementary particles, thereby violating the…

宇宙学与河外天体物理 · 物理学 2019-06-19 S. A. Levshakov , K. -W. Ng , C. Henkel , B. Mookerjea , I. I. Agafonova , S. -Y. Liu , W. -H. Wang

Aiming at providing a firm mean distance estimate to the Small Magellanic Cloud (SMC), and thus to place it within the internally consistent Local Group distance framework we recently established, we compiled the current-largest database of…

太阳与恒星天体物理 · 物理学 2015-05-20 Richard de Grijs , Giuseppe Bono

We use measurements from the Planck satellite mission and galaxy redshift surveys over the last decade to test three of the basic assumptions of the standard model of cosmology, $\Lambda$CDM: the spatial curvature of the universe, the…

宇宙学与河外天体物理 · 物理学 2016-01-20 Shadab Alam , Shirley Ho , Alessandra Silvestri

Anomalous Cepheids (ACs) are less studied metal-poor pulsating stars ([Fe/H]<-1.5) compared to Classical Cepheids (CCs) and RR Lyrae stars. They follow distinct Period-Luminosity (PL) and Period-Wesenheit (PW) relations and pulsate in…

In the era of precision cosmology it is essential to determine the Hubble Constant with an accuracy of 3% or better. Currently, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC) which as the…

In this Letter, we demonstrate that short-period stars orbiting around the supermassive black hole in our Galactic Center can successfully be used to probe the gravitational theory in a strong regime. We use 19 years of observations of the…

We present a sample of 76 double-mode Cepheids detected in the 4.5 square degree area in the central part of the LMC. 19 stars from the sample pulsate in the fundamental mode and the first overtone while 57 objects are the first and second…

天体物理学 · 物理学 2007-05-23 I. Soszynski , A. Udalski , M. Szymanski , M. Kubiak , G. Pietrzynski , P. Wozniak , K. Zebrun

We undertake a new test of the metallicity sensitivity of the Leavitt Law for Classical Cepheids. We derive an empirical calibration of the apparent luminosities of Cepheids as measured from the optical through the mid-infrared (0.45-8.0um)…

太阳与恒星天体物理 · 物理学 2015-05-27 Wendy L. Freedman , Barry F. Madore

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…

天体物理学 · 物理学 2009-10-28 Myungshin Im , Richard E. Griffiths , Kavan U. Ratnatunga

We present for the first time extended stellar density and/or surface brightness radial profiles for almost all the known Large Magellanic Cloud (LMC) old globular clusters (GCs). These were built from DECam images and reach out to ~ 4…

星系天体物理 · 物理学 2018-05-02 A. E. Piatti , A. D. Mackey

The period-change rate (PCR) of pulsating variable stars is a useful probe of changes in their interior structure, and thus of their evolutionary stages. So far, the PCRs of Classical Cepheids in the Large Magellanic Cloud (LMC) have been…