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Johan Richard

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Related publications (46)

[C II] emission in z similar to 6 strongly lensed, star-forming galaxies

Johan Richard, Jean-Paul Richard Kneib, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

The far-infrared fine-structure line [C II] at 1900.5 GHz is known to be one of the brightest cooling lines in local galaxies, and therefore it has been suggested to be an efficient tracer for star formation in very high redshift galaxies. However, recent ...

Oxford Univ Press2016

The evolution of the [O II], H beta and [O III] emission line luminosity functions over the last nine billions years

Johan Richard, Johan Comparat, Jeffrey Newman, Jean-Paul Richard Kneib, Timothée Guy Olivier Delubac, Anand Stéphane Raichoor

Emission line galaxies are one of the main tracers of the large-scale structure to be targeted by the next-generation dark energy surveys. To provide a better understanding of the properties and statistics of these galaxies, we have collected spectroscopic ...

Oxford Univ Press2016

The extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744

Johan Richard, Céline Tchernin, Jean-Paul Richard Kneib, Huanyuan Shan, Hakim Atek, Richard Massey, Markus Rexroth, David Richard Harvey, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

We present a joint optical/X-ray analysis of the massive galaxy cluster Abell 2744 (z = 0.308). Our strong- and weak-lensing analysis within the central region of the cluster, i.e. at R < 1 Mpc from the brightest cluster galaxy, reveals eight substructures ...

Oxford Univ Press2016

4MOST: the 4-metre Multi-Object Spectroscopic Telescope project at preliminary design review

Johan Richard, Jean-Paul Richard Kneib

We present an overview of the 4MOST project at the Preliminary Design Review. 4MOST is a major new wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of ESO. 4MOST has a broad range of science goals ranging f ...

Spie-Int Soc Optical Engineering2016

A complete census of Herschel-detected infrared sources within the HST Frontier Fields

Johan Richard, Jean-Paul Richard Kneib, Benjamin Yvan Alexandre Clement

We present a complete census of all Herschel-detected sources within the six massive lensing clusters of the HST Frontier Fields (HFF). We provide a robust legacy catalogue of 263 sources with Herschel fluxes, primarily based on imaging from the Herschel L ...

Wiley-Blackwell2016

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

Johan Richard, Jean-Paul Richard Kneib

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

ARE ULTRA-FAINT GALAXIES AT z=6-8 RESPONSIBLE FOR COSMIC REIONIZATION? COMBINED CONSTRAINTS FROM THE HUBBLE FRONTIER FIELDS CLUSTERS AND PARALLELS

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

We use deep Hubble Space Telescope imaging of the Frontier Fields to accurately measure the galaxy rest-frame ultraviolet luminosity function (UV LF) in the redshift range z similar to 6-8. We combine observations in three lensing clusters, A2744, MACS 041 ...

Iop Publishing Ltd2015

Warm-hot baryons comprise 5-10 per cent of filaments in the cosmic web

Johan Richard, Céline Tchernin, Jean-Paul Richard Kneib, Huanyuan Shan, Richard Massey, Mathilde Jauzac

Observations of the cosmic microwave background indicate that baryons account for 5 per cent of the Universe's total energy content(1). In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two(2,3). Cosmolog ...

Nature Publishing Group2015

The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827

Johan Richard, Richard Massey, David Richard Harvey, Mathilde Jauzac

Galaxy cluster Abell 3827 hosts the stellar remnants of four almost equally bright elliptical galaxies within a core of radius 10 kpc. Such corrugation of the stellar distribution is very rare, and suggests recent formation by several simultaneous mergers. ...

Oxford University Press2015

Hubble Frontier Fields: the geometry and dynamics of the massive galaxy cluster merger MACSJ0416.1-2403

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Richard Massey, Markus Rexroth, David Richard Harvey, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

We use a joint optical/X-ray analysis to constrain the geometry and history of the ongoing merging event in the massive galaxy cluster MACSJ0416.1-2403 (z = 0.397). Our investigation of cluster substructure rests primarily on a combined strong-and weak-len ...

Wiley-Blackwell2015

Hubble Frontier Fields: a high-precision strong-lensing analysis of the massive galaxy cluster Abell 2744 using similar to 180 multiple images

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Richard Massey, Markus Rexroth, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

We present a high-precision mass model of galaxy cluster Abell 2744, based on a strong gravitational-lensing analysis of the Hubble Space Telescope Frontier Fields (HFF) imaging data, which now include both Advanced Camera for Surveys and Wide Field Camera ...

Oxford University Press2015

New constraints on the faint end of the UV luminosity function at z∼ 7-8 using the gravitational lensing of the hubble frontier fields cluster A2744

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

Exploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant universe far beyond the limits of blank field surveys. Using the complete Hubble Space Telescope ob ...

American Astronomical Society2015

The 0.1 < z < 1.65 evolution of the bright end of the [O II] luminosity function

Johan Richard, Johan Comparat, Jean-Paul Richard Kneib, Timothée Guy Olivier Delubac, Jun Ma, David Schlegel, Zhenyu Wu

We present the [O II] (lambda lambda 3729; 3726) luminosity function measured in the redshift range 0.1 < z < 1.65 with unprecedented depth and accuracy. Our measurements are based on medium resolution flux-calibrated spectra of emission line galaxies with ...

EDP Sciences2015

Star formation histories, extinction, and dust properties of strongly lensed z similar to 1.5-3 star-forming galaxies from the Herschel Lensing Survey

Johan Richard, Jean-Paul Richard Kneib

Context. Multi-wavelength, optical to IR/submm observations of strongly lensed galaxies identified by the Herschel Lensing Survey are used to determine the physical properties of high-redshift star-forming galaxies close to or below the detection limits of ...

EDP Sciences2014

Lensed Type Ia supernovae as probes of cluster mass models

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek

Using three magnified Type Ia supernovae (SNe Ia) detected behind CLASH (Cluster Lensing and Supernovae with Hubble) clusters, we perform a first pilot study to see whether standardizable candles can be used to calibrate cluster mass maps created from stro ...

Wiley-Blackwell2014

The first Frontier Fields cluster: 4.5 mu m excess in a z similar to 8 galaxy candidate in Abell 2744

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Benjamin Yvan Alexandre Clement

Aims. We present in this letter the first analysis of a: 8 galaxy candidate found in the Hubble and Spitzer imaging data of Abell 2744 as part of the Hubble Frontier Fields legacy program. Methods. We applied the most commonly used methods to select except ...

EDP Sciences2014

[C II] and 12CO (1-0) emission maps in HLSJ091828. 6+ 514223: a strongly lensed interacting system at z= 5.24

Johan Richard, Jean-Paul Richard Kneib, Benjamin Yvan Alexandre Clement

We present Submillimeter Array [ C II] 158 mu m and Karl G. Jansky Very Large Array (CO)-C-12(1-0) line emission maps for the bright, lensed, submillimeter source at z = 5.2430 behind A 773: HLSJ091828.6+514223 (HLS0918). We combine these measurements with ...

American Astronomical Society2014

Probing the z> 6 universe with the first Hubble frontier fields cluster A2744

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

The Hubble Frontier Fields program combines the capabilities of the Hubble Space Telescope (HST) with the gravitational lensing of massive galaxy clusters to probe the distant universe to an unprecedented depth. Here, we present the results of the first co ...

American Astronomical Society2014

Disentangling a group of lensed submm galaxies at z similar to 2.9

Johan Richard, Jean-Paul Richard Kneib

MS 0451.6-0305 is a rich galaxy cluster whose strong lensing is particularly prominent at submm wavelengths. We combine new Submillimetre Common-User Bolometer Array (SCUBA)-2 data with imaging from Herschel Spectral and Photometric Imaging Receiver (SPIRE ...

Oxford University Press2014

Hubble Frontier Fields: a high-precision strong-lensing analysis of galaxy cluster MACSJ0416.1-2403 using similar to 200 multiple images

Johan Richard, Jean-Paul Richard Kneib, Hakim Atek, Richard Massey, Markus Rexroth, Mathilde Jauzac, Benjamin Yvan Alexandre Clement

We present a high-precision mass model of the galaxy cluster MACSJ0416.1-2403, based on a strong-gravitational-lensing analysis of the recently acquired Hubble Space Telescope Frontier Fields (HFF) imaging data. Taking advantage of the unprecedented depth ...

Oxford University Press2014

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