Publications associées à Observatoire W. M. Keck

CEERS: Diversity of Lyα Emitters during the Epoch of Reionization

We analyze rest-frame ultraviolet to optical spectra of three z similar or equal to 7.47-7.75 galaxies whose Ly alpha emission lines were previously detected with Keck/MOSFIRE observations, using the JWST/NIRSpec observations from the Cosmic Evolution Earl ...

Iop Publishing Ltd2024

Gaia'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 A2024

Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument

Stewart Cole, Jean-Paul Richard Kneib, Andrei Variu, Xin Chen, Daniel Felipe Forero Sanchez, Eduardo Sanchez, Zheng Zheng, Hua Zhang, Sun Hee Kim, Cheng Zhao, Anand Stéphane Raichoor, David Schlegel, Jiangyan Yang, Ting Tan, Zhifeng Ding, Arjun Dey

The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg(2) over 5 yr to constrain the cosmic expansion history through precise measurements of baryon acoustic oscillations (BAO). The scientific program for DESI ...

Iop Publishing Ltd2024

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

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

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

Pristine dwarf galaxy survey - I. A detailed photometric and spectroscopic study of the very metal-poor Draco II satellite

Pascale Jablonka, Silvia Martin de Nicolas Agut, Nicolas Lawrence Etienne Longeard

We present a detailed study of the faint Milky Way satellite Draco II (Dra II) from deep CFHT/MegaCam broad-band g and i photometry and narrow-band metallicity-sensitive CaliK observations, along with follow-up Keck II/DEIMOS multi-object spectroscopy. For ...

OXFORD UNIV PRESS2018

Robust sparse image reconstruction of radio interferometric observations with PURIFY

Yves Wiaux, Rafael Eduardo Carrillo Rangel, Jason Douglas McEwen

Next-generation radio interferometers, such as the Square Kilometre Array (SKA), will revolutionise our understanding of the universe through their unprecedented sensitivity and resolution. However, to realise these goals significant challenges in image an ...

OUP2016

The two-dimensional array of 2048 tilting micromirrors for astronomical spectroscopy

Nico de Rooij, Michael David Canonica, Wilfried Noell

In multi-object spectrometers, field selectors, which are located in the focal plane of the telescopes, are required for the selection of astronomical objects, such as stars or faint galaxies. We present a two-dimensional micromirror array as a field selec ...

Institute of Physics2013

Two Accurate Time-Delay Distances From Strong Lensing: Implications For Cosmology

Frédéric Courbin, Georges Meylan, Malte Tewes

Strong gravitational lenses with measured time delays between the multiple images and models of the lens mass distribution allow a one-step determination of the time-delay distance, and thus a measure of cosmological parameters. We present a blind analysis ...

American Astronomical Society2013

Large micromirror array for generating programmable slit masks for Multi-Object Spectroscopy

Nico de Rooij, Michael David Canonica, Wilfried Noell

Multi-object spectroscopy (MOS) is a powerful tool for space and ground-based telescopes for the study of the formation and evolution of galaxies. This technique requires a programmable slit mask for astronomical object selection. We are engaged in a Europ ...

Spie-Int Soc Optical Engineering2012

Three quasi-stellar objects acting as strong gravitational lenses

Frédéric Courbin, Georges Meylan, Malte Tewes, François Henri Ambroise Rérat

We report the discovery of three new cases of quasi-stellar objects (QSOs) acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (z(QSO) = 0.293, z(s) = 0.412), SDSS J0919+2720 (z(QSO) = 0.209, z(s) = 0.558), SDSS J100 ...

2012

Large Micromirror Array Based on a Scalable Technology for Astronomical Instrumentation

Michael David Canonica

Understanding the formation of galaxies and studying the expansion of the Universe, need the spectral characterization of faint astronomical objects such as stars or galaxies. From these spectra, the distance, the velocity and the chemical composition of t ...

EPFL2012

Intrinsic advantages of the w component and spherical imaging for wide-field radio interferometry

Yves Wiaux, Jason Douglas McEwen

Incorporating wide-field considerations in interferometric imaging is of increasing importance for next-generation radio telescopes. Compressed sensing techniques for interferometric imaging have been extended to wide fields recently, recovering images in ...

2011

First case of strong gravitational lensing by a QSO: SDSS J0013+1523 at z=0.120

Frédéric Courbin, Georges Meylan, Malte Tewes, François Henri Ambroise Rérat

We present the first case of strong gravitational lensing by a QSO: SDSS J0013 + 1523 at z = 0.120. The discovery is the result of a systematic search for emission lines redshifted behind QSOs, among 22 298 spectra of the SDSS data release 7. Apart from th ...

2010

Deep optical spectroscopy of extended Ly alpha emission around three radio-quiet z=4.5 quasars

Frédéric Courbin, Pierre North, Alexander Patrick Eigenbrod

We report the first results of a spectroscopic search for Ly alpha envelopes around three z similar to 4.5 radio-quiet quasars. Our observational strategy adopts the FORS2 spectrograph mounted to the UT1 of the Very Large Telescope (VLT) in the multi-slit ...

2008