Concept

Anneau d'Einstein

Publications associées (88)

Astrophysical applications of gravitationally lensed quasars

Gravitational lensing describes how light is deflected as it passes in the vicinity of a mass distribution. The amplitude of the deflection is proportional to the mass of the deflector, called "gravitational lens", and is generally weak, even for large mas ...

EPFL2008

Microlensing variability in the gravitationally lensed quasar QSO 2237+0305 equivalent to the Einstein Cross - I. Spectrophotometric monitoring with the VLT

Frédéric Courbin, Georges Meylan, Alexander Patrick Eigenbrod

We present the results of the first long-term (2.2 years) spectroscopic monitoring of a gravitationally lensed quasar, namely the Einstein Cross QSO 2237+0305. The goal of this paper is to present the observational facts to be compared in follow-up papers ...

2008

A sharp look at the gravitationally lensed quasar SDSS J0806+2006 with laser guide star adaptive optics at the VLT

Frédéric Courbin, Georges Meylan, Alexander Patrick Eigenbrod

We present the first VLT near-IR observations of a gravitationally lensed quasar, using adaptive optics and laser guide star. These observations can be considered as a test bench for future systematic observations of lensed quasars with adaptive optics, ev ...

2008

COSMOGRAIL: the COSmological MOnitoring of GRAvItational lenses - VII. Time delays and the Hubble constant from WFI J2033-4723

Frédéric Courbin, Georges Meylan, Christel Vuissoz

Gravitationally lensed quasars can be used to map the mass distribution in lensing galaxies and to estimate the Hubble constant H-0 by measuring the time delays between the quasar images. Here we report the measurement of two independent time delays in the ...

2008

Gravitational lenses

Christel Vuissoz

The Hubble constant H0 is one of the most important parameters in cosmology, as it encodes the age of the Universe and is necessary for any distance determination at a cosmological scale. It is, however, only poorly constrained by traditional methods. The ...

EPFL2008

Microlensing probes the AGN structure of the lensed quasar J1131-1231

We present the analysis of single epoch long slit spectra of the three brightest images of the gravitationally lensed system J1131-1231. These spectra provide one of the clearest observational evidence for differential micro-lensing of broad emission lines ...

Universidad Nacional Autonoma Mexico Instituto Astronomia, Apartado Postal 70-264, Mexico City 04510, Mexico2008

Simultaneous estimation of time delays and quasar structure

Frédéric Courbin, Georges Meylan, Christel Vuissoz

We expand our Bayesian Monte Carlo method for analyzing the light curves of gravitationally lensed quasars to simultaneously estimate time delays and the sizes of quasar continuum emission regions including their mutual uncertainties. We apply the method t ...

2008

Hubble Space Telescope Observations of the Lensing Cluster Abell 2218

Jean-Paul Richard Kneib

We present a striking new Hubble Space Telescope (HST) observation of the rich cluster Abell 2218 taken with the Wide-Field and Planetary Camera (WFPC2). HST's restored image quality reveals a sizeable number of gravitationally-lensed features in this clus ...

1996

Graph Chatbot

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.

Connectez-vous pour utiliser Chat avec Graph Search