Personne
Nicolas Lawrence Etienne Longeard
Publications associées (15)
Stellar Metallicities and Gradients in the Isolated, Quenched Low-mass Galaxy Tucana
Nicolas Lawrence Etienne Longeard
We measure the metallicities of 374 red giant branch (RGB) stars in the isolated, quenched dwarf galaxy Tucana using Hubble Space Telescope (HST) narrow-band (F395N) Calcium H & K (CaHK) imaging. Our sample is a factor of similar to 7 similar to 7 larger t ...
Iop Publishing Ltd2024Gaia's brightest very metal-poor (VMP) stars Metallicity catalogue of a thousand VMP stars from Gaia's radial velocity spectrometer spectra
Nicolas Lawrence Etienne Longeard
Context. Gaia DR3 has offered the scientific community a remarkable dataset of approximately one million spectra acquired with the radial velocity spectrometer (RVS) in the calcium II triplet region, which is well suited to identify very metal-poor (VMP) s ...
Edp Sciences S A2024The Pristine dwarf galaxy survey-V. The edges of the dwarf galaxy Hercules
Pascale Jablonka, Nicolas Lawrence Etienne Longeard
We present a new spectroscopic study of 175 stars in the vicinity of the dwarf galaxy Hercules (d similar to 132 kpc) with data from the Anglo-Australian Telescope and its AAOmega spectrograph together with the Two Degree Field multi-object system to solve ...
OXFORD UNIV PRESS2023Metallicity Distribution Functions of 13 Ultra-faint Dwarf Galaxy Candidates from Hubble Space Telescope Narrowband Imaging
Nicolas Lawrence Etienne Longeard
We present uniformly measured stellar metallicities of 463 stars in 13 Milky Way (MW) ultra-faint dwarf galaxies (UFDs; M-V = -7.1 to -0.8) using narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope. This represents the largest homogeneous ...
Bristol2023The Pristine dwarf galaxy survey - IV. Probing the outskirts of the dwarf galaxy Bootes I
Pascale Jablonka, Nicolas Lawrence Etienne Longeard, Romain Ely Roland Lucchesi
We present a new spectroscopic study of the dwarf galaxy Bootes I (Boo I) with data from the Anglo-Australian Telescope and its AAOmega spectrograph together with the Two Degree Field multi-object system. We observed 36 high-probability Boo I stars selecte ...
OXFORD UNIV PRESS2022Metallicity Distribution Function of the Eridanus II Ultra-faint Dwarf Galaxy from Hubble Space Telescope Narrowband Imaging
Nicolas Lawrence Etienne Longeard
We use deep narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope (HST) to construct the metallicity distribution function (MDF) of Local Group ultra-faint dwarf galaxy Eridanus II (Eri II). When combined with archival F475W and F814W data, ...
IOP Publishing Ltd2022The Pristine Dwarf-Galaxy survey - II. In-depth observational study of the faint Milky Way satellite Sagittarius II
Pascale Jablonka, Nicolas Lawrence Etienne Longeard
We present an extensive study of the Sagittarius II (Sgr II) stellar system using MegaCam g and i photometry, narrow-band, metallicity-sensitive calcium H&K doublet photometry and Keck II/DEIMOS multiobject spectroscopy. We derive and refine the Sgr II str ...
OXFORD UNIV PRESS2020The Pristine survey - X. A large population of low-metallicity stars permeates the Galactic disc
Pascale Jablonka, Pierre North, Nicolas Lawrence Etienne Longeard, Romain Ely Roland Lucchesi
The orbits of the least chemically enriched stars open a window on the formation of our Galaxy when it was still in its infancy. The common picture is that these low-metallicity stars are distributed as an isotropic, pressure-supported component since thes ...
OXFORD UNIV PRESS2020The Pristine Inner Galaxy Survey (PIGS) I: tracing the kinematics of metal-poor stars in the Galactic bulge
Nicolas Lawrence Etienne Longeard, Carmela Lardo
Our Galaxy is known to contain a central boxy/peanut-shaped bulge, yet the importance of a classical, pressure-supported component within the central part of the Milky Way is still being debated. It should be most visible at low metallicity, a regime that ...
OXFORD UNIV PRESS2020The Hidden Past of M92: Detection and Characterization of a Newly Formed 17 degrees Long Stellar Stream Using the Canada-France Imaging Survey
Nicolas Lawrence Etienne Longeard
We present an analysis of the structure, kinematics, and orbit of a newly found stellar stream emanating from the globular cluster M92 (NGC 6341). This stream was discovered in an improved matched-filter map of the outer Galaxy, based on a "color-color-mag ...
IOP PUBLISHING LTD2020