J. P. Willis
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View article: A morphological analysis of the galaxy cluster XLSSC 122 at <i>z </i>= 1.98
A morphological analysis of the galaxy cluster XLSSC 122 at <i>z </i>= 1.98 Open
We present a morphological analysis of 29 spectroscopically confirmed members of XLSSC 122, a massive galaxy cluster at $z=1.98$. We perform photometry using statmorph on images of the cluster members from the Hubble Space Telescope (HST) …
View article: The XXL Survey
The XXL Survey Open
Context. X-ray observations of galaxy clusters are impacted by the presence of active galactic nuclei (AGNs) in a manner that is challenging to quantify, leading to biases in the detection and measurement of cluster properties for both ast…
View article: The XXL Survey L. Active galactic nucleus contamination in galaxy clusters: Detection and cosmological impact
The XXL Survey L. Active galactic nucleus contamination in galaxy clusters: Detection and cosmological impact Open
X-ray observations of galaxy clusters are impacted by the presence of active galactic nuclei (AGNs) in a manner that is challenging to quantify, leading to biases in the detection and measurement of cluster properties for both astrophysics…
View article: The XXL survey. XLIX. Linking the members star formation histories to the cluster mass assembly in the z = 1.98 galaxy cluster XLSSC 122
The XXL survey. XLIX. Linking the members star formation histories to the cluster mass assembly in the z = 1.98 galaxy cluster XLSSC 122 Open
The most massive protoclusters virialize to become clusters at z ∼ 2, which is also a critical epoch for the evolution of their member galaxies. XLSSC 122 is a z = 1.98 galaxy cluster with 37 spectroscopically confirmed members. We aim to …
View article: The XXL Survey
The XXL Survey Open
Why are some galaxy groups pervaded by a hot X-ray emitting intracluster medium, whilst others have no detectable X-ray emission? Is the presence of hot gas a reliable indicator of dynamical maturity, and can some virialised groups contain…
View article: The XXL Survey – XLVIII. X-ray follow-up of distant XXL clusters: masses, scaling relations, and AGN contamination
The XXL Survey – XLVIII. X-ray follow-up of distant XXL clusters: masses, scaling relations, and AGN contamination Open
We use deep follow-up XMM–Newton observations of six clusters discovered in the XXL Survey at z > 1 to gain robust measurements of their X-ray properties and to investigate the extent to which scaling relations at low redshift are valid…
View article: Quiescent galaxies in a virialized cluster at redshift 2: evidence for accelerated size growth
Quiescent galaxies in a virialized cluster at redshift 2: evidence for accelerated size growth Open
We present an analysis of the galaxy population in XLSSC 122, an X-ray-selected, virialized cluster at redshift z = 1.98. We utilize Hubble Space Telescope (HST)Wide Field Camera 3 (WFC3) photometry to characterize the activity and morphol…
View article: Revealing the star formation history of a mature galaxy cluster at z=2
Revealing the star formation history of a mature galaxy cluster at z=2 Open
At z=1.98, XLSSC 122 is a massive and mature galaxy cluster with 37 spectroscopically confirmed members. We employ12 band PSF-matched photometry and BAGPIPES SED modelling to investigate the star formation histories, stellar mass, dust and…
View article: Understanding X-ray and optical selection of galaxy clusters: a comparison of the XXL and CAMIRA cluster catalogues obtained in the common XXL-HSC SSP area
Understanding X-ray and optical selection of galaxy clusters: a comparison of the XXL and CAMIRA cluster catalogues obtained in the common XXL-HSC SSP area Open
Large samples of galaxy clusters provide knowledge of both astrophysics in the most massive virialized environments and the properties of the cosmological model that defines our Universe. However, an important issue that affects the interp…
View article: The XXL Survey
The XXL Survey Open
Context. Distant galaxy clusters provide an effective laboratory in which to study galaxy evolution in dense environments and at early cosmic times. Aims. We aim to identify distant galaxy clusters as extended X-ray sources that are coinci…
View article: Science, Technical and Strategic benefits of Canadian partnership with Subaru
Science, Technical and Strategic benefits of Canadian partnership with Subaru Open
Recent developments have opened up an opportunity to join the Subaru telescope under favourable terms. With the demonstrated success of SCExAO and HSC, and first light of the PFS nearly upon us, the immediate prospects for Subaru to make b…
View article: The Maunakea Spectroscopic Explorer
The Maunakea Spectroscopic Explorer Open
The Maunakea Spectroscopic Explorer (MSE) is a project to design and construct a wide-field spectroscopic telescope at a site with excellent natural seeing, and in so doing to continue the tradition of Canadian leadership in wide-field ast…
View article: X-ray versus infrared selection of distant galaxy clusters: a case study using the XMM–LSS and SpARCS cluster samples
X-ray versus infrared selection of distant galaxy clusters: a case study using the XMM–LSS and SpARCS cluster samples Open
We present a comparison of two samples of z>0.8 galaxy clusters selected\nusing different wavelength-dependent techniques and examine the physical\ndifferences between them. We consider 18 clusters from the X-ray selected\nXMM-LSS distant …
View article: A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)
A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) Open
The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band (NB) Hα +[NII] imaging survey carried out with MegaCam at the Canada–France–Hawaii Telescope. The survey covers the whole Virgo cluster region fro…
View article: The XXL Survey
The XXL Survey Open
Context. In the currently debated context of using clusters of galaxies as cosmological probes, the need for well-defined cluster samples is critical. Aims. The XXL Survey has been specifically designed to provide a well characterised samp…
View article: The XXL Survey
The XXL Survey Open
Context. The fraction of galaxies bound in groups in the nearby Universe is high (50% at z ~ 0). Systematic studies of galaxy properties in groups are important in order to improve our understanding of the evolution of galaxies and of the …
View article: The <scp>XXL</scp> survey: First results and future
The <span>XXL</span> survey: First results and future Open
The XXL survey currently covers two 25 deg 2 patches with XMM observations of ∼10 ks. We summarize the scientific results associated with the first release of the XXL dataset, which occurred in mid‐2016. We review several arguments for inc…
View article: The XXL survey XV: evidence for dry merger driven BCG growth in XXL-100-GC X-ray clusters
The XXL survey XV: evidence for dry merger driven BCG growth in XXL-100-GC X-ray clusters Open
The growth of brightest cluster galaxies (BCGs) is closely related to the properties of their host cluster. We present evidence for dry mergers as the dominant source of BCG mass growth at z ≲ 1 in the XXL 100 brightest cluster sample…
View article: The XXL Survey
The XXL Survey Open
Context. X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). Usually, a combination of deep and wide surveys is necessary to create a complete picture of the pop…
View article: The Detailed Science Case for the Maunakea Spectroscopic Explorer: the Composition and Dynamics of the Faint Universe
The Detailed Science Case for the Maunakea Spectroscopic Explorer: the Composition and Dynamics of the Faint Universe Open
MSE is an 11.25m aperture observatory with a 1.5 square degree field of view that will be fully dedicated to multi-object spectroscopy. More than 3200 fibres will feed spectrographs operating at low (R ~ 2000 - 3500) and moderate (R ~ 6000…
View article: The XXL Survey
The XXL Survey Open
Aims. Within a cluster, gravitational effects can lead to the removal of stars from their parent galaxies and their subsequent dispersal into the intracluster medium. Gas hydrodynamical effects can additionally strip gas and dust from gala…
View article: The XXL Survey
The XXL Survey Open
We present the XXL Survey, the largest XMM programme totaling some 6.9 Ms to\ndate and involving an international consortium of roughly 100 members. The XXL\nSurvey covers two extragalactic areas of 25 deg2 each at a point-source\nsensitiv…
View article: The XXL Survey
The XXL Survey Open
The XXL survey is the largest survey carried out by XMM-Newton. Covering an\narea of 50deg$^2$, the survey contains $\\sim450$ galaxy clusters out to a\nredshift $\\sim$2 and to an X-ray flux limit of\n$\\sim5\\times10^{-15}erg\\,s^{-1}cm^…