Publications associées à Diagramme de Hertzsprung-Russell

Tracing the rise of supermassive black holes A panchromatic search for faint, unobscured quasars at z ≥ 6 with COSMOS-Web and other surveys

We report the identification of 64 new candidates of compact galaxies, potentially hosting faint quasars with bolometric luminosities of L-bol = 10(43)-10(46) erg s(-1), residing in the reionization epoch within the redshift range of 6 less than or similar ...

Edp Sciences S A2024

How much metal did the first stars provide to the ultra-faint dwarfs?

Pascale Jablonka, Yves Revaz, Mahsa Sanati

Numerical simulations of dwarf galaxies have so far failed to reproduce the observed metallicity-luminosity relation, down to the regime of ultra-faint dwarfs (UFDs). We address this issue by exploring how the first generations of metal-free stars (Pop III ...

EDP SCIENCES S A2023

Impact of a companion and of chromospheric emission on the shape of chromosome maps for globular clusters

Carmela Lardo

Context. Globular clusters (GCs) host multiple populations of stars that are well-separated in a photometric diagram - the chromosome map - built from specific Hubble Space Telescope (HST) filters. Stars from different populations feature at various locati ...

EDP SCIENCES S A2020

How stellar rotation shapes the colour-magnitude diagram of the massive intermediate-age star cluster NGC 1846

Carmela Lardo

We present a detailed study of stellar rotation in the massive 1.5 Gyr old cluster NGC 1846 in the Large Magellanic Cloud. Similar to other clusters at this age, NGC 1846 shows an extended main-sequence turn-off (eMSTO), and previous photometric studies ha ...

OXFORD UNIV PRESS2020

Extended main sequence turnoffs in open clusters as seen by Gaia - II. The enigma of NGC 2509

Carmela Lardo

We investigate the morphology of the colour-magnitude diagram (CMD) of the open cluster NGC 2509 in comparison with other Galactic open clusters of similar age using Gaia photometry. At similar to 900 Myr Galactic open clusters in our sample all show an ex ...

OXFORD UNIV PRESS2020

The Tucana dwarf spheroidal galaxy: not such a massive failure after all

Pascale Jablonka

Context. Isolated local group (LG) dwarf galaxies have evolved most or all of their life unaffected by interactions with the large LG spirals and therefore offer the opportunity to learn about the intrinsic characteristics of this class of objects. Aims. O ...

2020

Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era

Pierre North

Context. Li is extensively known to be a good tracer of non-standard mixing processes occurring in stellar interiors. Aims. We present the results of a new large Li survey in red giant stars and combine it with surveys from the literature to probe the impa ...

EDP SCIENCES S A2020

Disappearance of the extended main sequence turn-off in intermediate age clusters as a consequence of magnetic braking

Tomás Alfredo Trewhela Palacios, Carmela Lardo

Context. Extended main sequence turn-offs are features commonly found in the colour-magnitude diagrams of young and intermediate age (less than about 2 Gyr) massive star clusters, where the main sequence turn-off is broader than can be explained by photome ...

EDP SCIENCES S A2019

Barium and related stars, and their white-dwarf companions

Pierre North, Conrad Johnston, Shreeya Sushil Shetye

Barium (Ba) dwarfs and CH subgiants are the less evolved analogues of Ba and CH giants. They are F- to G-type main-sequence stars polluted with heavy elements by their binary companions when the companion was on the asymptotic giant branch (AGB). This comp ...

EDP SCIENCES S A2019

Chemical inhomogeneities amongst first population stars in globular clusters Evidence for He variations

Carmela Lardo

Spreads in light element abundances among stars (also known as multiple populations) are observed in nearly all globular clusters. One way to map such chemical variations using high-precision photometry is to employ a suitable combination of stellar magnit ...

EDP SCIENCES S A2018

Population gradient in the Sextans dSph: comprehensive mapping of a dwarf galaxy by Suprime-Cam

Pascale Jablonka

We present the deep and wide V and I-c photometry of the Sextans dwarf spheroidal galaxy (dSph) taken by the Suprime-Cam imager on the Subaru Telescope, which extends out to the tidal radius. The colour-magnitude diagram (CMD) reaches two magnitudes below ...

Oxford Univ Press2017

Testing parallaxes with local Cepheids and RR Lyrae stars

Stephan Morgenthaler, Mikaël Martino, Shuangqing Liao

Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the HIPPARCOS and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Ai ...

Edp Sciences S A2017

Evaluating the effect of stellar multiplicity on the point spread function of space-based weak lensing surveys

Frédéric Courbin, Georges Meylan, Thibault Adrien Kuntzer

The next generation of space-based telescopes used for weak lensing surveys will require exquisite point spread function (PSF) determination. Previously negligible effects may become important in the reconstruction of the PSF, in part because of the improv ...

Edp Sciences S A2016

Molecular gas content in strongly lensed z similar to 1.5-3 star-forming galaxies with low infrared luminosities

Jean-Paul Richard Kneib, Johan Richard

To extend the molecular gas measurements to more typical star-forming galaxies (SFGs) with star formation rates SFR < 40 M-circle dot yr(-1) and stellar masses M-* < 2.5 x 10(10) M-circle dot at z similar to 1.5-3, we have observed CO emission with the IRA ...

EDP Sciences2015

Physical properties and evolutionary state of the Lyman alpha emitting starburst galaxy IRAS 08339+6517

Hakim Atek

Context. Though Ly alpha emission is one of the most used tracers of massive star formation at high redshift, it is strongly affected by neutral gas radiation transfer effects. A correct understanding of these effects is required to properly quantify the s ...

EDP Sciences2014

Uvudf: Ultraviolet Imaging Of The Hubble Ultra Deep Field With Wide-Field Camera 3

Hakim Atek

We present an overview of a 90 orbit Hubble Space Telescope treasury program to obtain near-ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey is designed to: ...

Institute of Physics2013

The colour-magnitude relation of elliptical and lenticular galaxies in the ESO Distant Cluster Survey

Pascale Jablonka

In this paper we study the colour-magnitude relation (CMR) for a sample of 172 morphologically classified elliptical and S0 cluster galaxies from the ESO Distant Cluster Survey (EDisCS) at 0.4 less than or similar to z less than or similar to 0.8. The intr ...

Blackwell Publishing Ltd, Oxford2011

The fundamental plane of EDisCS galaxies The effect of size evolution

Pascale Jablonka

We study the evolution of spectral early-type galaxies in clusters, groups, and the field up to redshift 0.9 using the ESO Distant Cluster Survey (EDisCS) dataset. We measure structural parameters (circularized half-luminosity radii R-e, surface brightness ...

2010

The Low-Mass Initial Mass Function In The 30 Doradus Starburst Cluster

Marilyne Andersen, Georges Meylan

We present deep Hubble Space Telescope NICMOS 2 F160W band observations of the central 56 '' x 57 '' (14 pc x 14.25 pc) region around R136 in the starburst cluster 30Dor (NGC 2070) located in the Large Magellanic Cloud. Our aim is to derive the stellar ini ...

2009

THE REST-FRAME OPTICAL LUMINOSITY FUNCTION OF CLUSTER GALAXIES AT z < 0.8 AND THE ASSEMBLY OF THE CLUSTER RED SEQUENCE

Pascale Jablonka, Anja Von der Linden

We present the rest-frame optical luminosity function (LF) of red-sequence galaxies in 16 clusters at 0.4 < z < 0.8 drawn from the ESO Distant Cluster Survey (EDisCS). We compare our clusters to an analogous sample from the Sloan Digital Sky Survey (SDSS) ...

2009