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Concept

Objet circumbinaire

Publications associées (12)

White dwarfs as a probe of exceptionally light QCD axions

Stefan Stelzl

We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the nonderivative coupling of the axion to nucleons displaces the axion from its invacuum minimum, which implies a reduction of t ...

American Physical Society2024

The Pristine survey - XXI. Exploring the metal-poor boundary with ESPaDoNS

Pascale Jablonka

In this paper, we study high-resolution spectra of 19 stars that have metallicity estimates below -3.5 using at least two metallicity-sensitive photometric indices based on Pristine photometry. The purpose is to understand what kind of stars populate this ...

OXFORD UNIV PRESS2023

LensWatch. I. Resolved HST Observations and Constraints on the Strongly Lensed Type Ia Supernova 2022qmx ("SN Zwicky")

Frédéric Courbin

Supernovae (SNe) that have been multiply imaged by gravitational lensing are rare and powerful probes for cosmology. Each detection is an opportunity to develop the critical tools and methodologies needed as the sample of lensed SNe increases by orders of ...

IOP Publishing Ltd2023

Measuring accretion disk sizes of lensed quasars with microlensing time delay in multi-band light curves

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin, Martin Raoul Robert Millon, Karina Alexandra Rojas Olate

Time-delay cosmography in strongly lensed quasars offers an independent way of measuring the Hubble constant, H-0. However, it has been proposed that the combination of microlensing and source-size effects, also known as microlensing time delay, can potent ...

EDP SCIENCES S A2021

COSMOGRAIL XVII. Time delays for the quadruply imaged quasar PG 1115+080

Sun Hee Kim, Frédéric Courbin, Georges Meylan, Hung-Hsu Chan, Vivien François Bonvin, Malte Tewes, Martin Raoul Robert Millon, Karina Alexandra Rojas Olate, Eric Gérard Guy Paic

We present time-delay estimates for the quadruply imaged quasar PG 1115+080. Our results are based on almost daily observations for seven months at the ESO MPIA 2.2m telescope at La Silla Observatory, reaching a signal-to-noise ratio of about 1000 per quas ...

EDP SCIENCES S A2018

Constraining the microlensing effect on time delays with a new time-delay prediction model in H-0 measurements

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin, Martin Raoul Robert Millon, Karina Alexandra Rojas Olate

Time-delay strong lensing provides a unique way to directly measure the Hubble constant (H-0). The precision of the H-0 measurement depends on the uncertainties in the time-delay measurements, the mass distribution of the main deflector(s), and the mass di ...

OXFORD UNIV PRESS2018

The Time-Domain Spectroscopic Survey: Understanding The Optically Variable Sky With Sequels In Sdss-Iii

Jean-Paul Richard Kneib

The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of similar to 220,000 optically variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a ...

Iop Publishing Ltd2016

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XI. Techniques for time delay measurement in presence of microlensing

Frédéric Courbin, Georges Meylan, Malte Tewes

Measuring time delays between the multiple images of gravitationally lensed quasars is now recognized as a competitive way to constrain the cosmological parameters, and it is complementary with other cosmological probes. This requires long and well sampled ...

Edp Sciences S A2013

Microlensing of the broad line region in 17 lensed quasars

Frédéric Courbin, Georges Meylan

When an image of a strongly lensed quasar is microlensed, the different components of its spectrum are expected to be differentially magnified owing to the different sizes of the corresponding emitting region. Chromatic changes are expected to be observed ...

Edp Sciences S A2012

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses

Frédéric Courbin, Georges Meylan, Yves Revaz, Malte Tewes

We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010. With seven years of data, we clearly show that quasar ...

2011

VLT multi-object spectroscopy of 33 eclipsing binaries in the Small Magellanic Cloud New distance and depth of the SMC, and a record-breaking apsidal motion

Pierre North, Romain Gauderon

Aims. Our purpose is to provide reliable stellar parameters for a significant sample of eclipsing binaries, which are representative of a whole dwarf and metal-poor galaxy. We also aim at providing a new estimate of the mean distance to the SMC and of its ...

2010

New distance and depth estimates from observations of eclipsing binaries in the SMC

Pierre North, Romain Gauderon

A sample of 33 eclipsing binaries observed in a field of the SMC with FLAMES@VLT is presented. The radial velocity curves obtained, together with existing OGLE light curves, allowed the determination of all stellar and orbital parameters of these binary sy ...

Cambridge University Press2009