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Publications associées (15)

The first generations of stars in the Local Group

The different projects of this thesis contribute to improving our understanding of the early chemical evolution of the galaxies.The standard cosmological model states an hierarchical formation of the galaxies, the dwarf galaxies being the first stellar sys ...

EPFL2022

The Pristine survey - XV. A CHIT ESPaDOnS view on the Milky Way halo and disc populations

Pascale Jablonka, Willem Suter, Carmela Lardo, Romain Ely Roland Lucchesi

We present a one-dimensional, local thermodynamic equilibrium homogeneous analysis of 132 stars observed at high resolution with ESPaDOnS. This represents the largest sample observed at high resolution (R similar to 40 000) from the Pristine survey. This s ...

OXFORD UNIV PRESS2022

The eta Aquilae System: Radial Velocities and Astrometry in Search of eta Aql B

The classical Cepheid eta Aql was not included in past Leavitt Law work because of a presumed complicating orbit due to a known B9.8V companion. To determine the orbit of eta Aql B, we analyze a significant number of radial velocity (RV) measurements from ...

2022

Cepheids with Giant Companions. I. Revealing a Numerous Population of Double-lined Binary Cepheids* (dagger)

Richard Irving Anderson

Masses of classical Cepheids of 3-11 M are predicted by theory but those measured clump between 3.6-5 M. As a result, their mass-luminosity relation is poorly constrained, impeding our understanding of basic stellar physics and the Leavitt Law. All Cepheid ...

2021

Towards Efficient and Accurate Numerical Simulations of Galaxies using Task-based Parallelism and Application to Dwarf Galaxies

Loïc Hausammann

Numerical simulations are of a tremendous help to understand the growth of non-linear cosmological structures and how they lead to the formation of galaxies. In recent years, with the goal of improving their prediction power, new hydrodynamical techniques ...

EPFL2021

Design of a Flexure Based Low Frequency Foucault Pendulum

Simon Nessim Henein, Ilan Vardi, Patrick Robert Flückiger

The Foucault pendulum is a well-known mechanism used to demonstrate the rotation of the Earth. It consists in a pendulum launched on linear orbits and, following Mach’s Principle, this line of oscillation will remain fixed with respect to absolute space bu ...

2020

The Pristine survey II: A sample of bright stars observed with FEROS

Pascale Jablonka

Extremely metal-poor (EMP) stars are old objects formed in the first Gyr of the Universe. They are rare and, to select them the most successful strategy has been to build on large and low-resolution spectroscopic surveys. The combination of narrow- and bro ...

Wiley-V C H Verlag Gmbh2017

The Pristine survey - III. Spectroscopic confirmation of an efficient search for extremely metal-poor stars

Pascale Jablonka, Marc Gentile

The Pristine survey is a narrow-band, photometric survey focused around the wavelength region of the Ca II H&K absorption lines, designed to efficiently search for extremely metal-poor stars. In this work, we use the first results of amedium-resolution spe ...

Oxford Univ Press2017

Gaia Data Release 1 Open cluster astrometry: performance, limitations, and future prospects

Stephan Morgenthaler, Mikaël Martino, Shuangqing Liao

Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 po ...

Edp Sciences S A2017

Carbon and nitrogen abundances of individual stars in the Sculptor dwarf spheroidal galaxy

Pascale Jablonka, Carmela Lardo

We present [C/Fe] and [N/Fe] abundance ratios and CH(lambda 4300) and S(lambda 3883) index measurements for 94 red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy from VLT/VIMOS MOS observations at a resolving power R = 1150 at 4020 A. Thi ...

Edp Sciences S A2016

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