Browsing by Author "Quintana, H."

Now showing 1 - 4 of 4
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    Distant galaxy clusters in a deep XMM-Newton field within the CFTHLS D4
    (2013) de Hoon, A.; Lamer, G.; Schwope, A.; Muehlegger, M.; Fassbender, R.; Boehringer, H.; Lerchster, M.; Nastasi, A.; Suhada, R.; Verdugo, M.; Dietrich, J. P.; Brimioulle, F.; Rosati, P.; Pierini, D.; Santos, J. S.; Quintana, H.; Rabitz, A.; Takey, A.
    Aims. The XMM-Newton distant cluster project (XDCP) aims at the identification of a well defined sample of X-ray selected clusters of galaxies at redshifts z >= 0.8. As part of this project, we analyse the deep XMM-Newton exposure covering one of the CFHTLS deep fields to quantify the cluster content. We validate the optical follow-up strategy as well as the X-ray selection function.
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    Scaling relations of the colour-detected cluster RzCS 052 at z=1.016 and some other high-redshift clusters
    (2008) Andreon, S.; De Propris, R.; Puddu, E.; Giordano, L.; Quintana, H.
    We report on the discovery of the z = 1.016 cluster RzCS 052 using a modified red-sequence method, follow up spectroscopy and X-ray imaging. This cluster has a velocity dispersion of 710 +/- 150 km s(-1), a virial mass of 4.0 x 10(14) M-circle dot (based on 21 spectroscopically confirmed members) and an X-ray luminosity of (0.68 +/- 0.47) x 10(44) erg s(-1) in the [1-4] keV band. This optically selected cluster appears to be of richness class 3 and to follow the known L-X-sigma(v) relation for high-redshift X-ray selected clusters. Using these data, we find that the halo occupation number for this cluster is only marginally consistent with what was expected assuming a self-similar evolution of cluster scaling relations, suggesting perhaps a break of them at z similar to 1. We also rule out a strong galaxy merging activity between z = 1 and today. Finally, we present a Bayesian approach to measuring cluster velocity dispersions and X-ray luminosities in the presence of a background: we critically reanalyse recent claims for X-ray underluminous clusters using these techniques and find that the clusters can be accommodated within the existing L-X-sigma(v) relation.
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    Structure and dynamics of the Shapley Supercluster -: Velocity catalogue, general morphology and mass
    (2006) Proust, D.; Quintana, H.; Carrasco, E.R.; Reisenegger, A.; Slezak, E.; Muriel, H.; Dünner, R.; Sodre, L.; Drinkwater, M.J.; Parker, Q.A.; Ragone, C.J.
    We present results of our wide-field redshift survey of galaxies in a 285 square degree region of the Shapley Supercluster (SSC), based on a set of 10 529 velocity measurements (including 1201 new ones) on 8632 galaxies obtained from various telescopes and from the literature. Our data reveal that the main plane of the SSC (v approximate to 14 500 km s(-1)) extends further than previous estimates, filling the whole extent of our survey region of 12 degrees by 30 degrees on the sky (30 x 75 h(-1) Mpc). There is also a connecting structure associated with the slightly nearer Abell 3571 cluster complex (v approximate to 12 000 km s(-1)). These galaxies seem to link two previously identified sheets of galaxies and establish a connection with a third one at v = 15 000 km s(-1) near RA = 13(h). They also tend to fill the gap of galaxies between the foreground Hydra-Centaurus region and the more distant SSC. In the velocity range of the Shapley Supercluster (9000 km s(-1) < cz < 18 000 km s(-1)), we found redshift-space overdensities with b(j) < 17.5 of similar or equal to 5.4 over the 225 square degree central region and similar or equal to 3.8 in a 192 square degree region excluding rich clusters. Over the large region of our survey, we find that the intercluster galaxies make up 48 per cent of the observed galaxies in the SSC region and, accounting for the different completeness, may contribute nearly twice as much mass as the cluster galaxies. In this paper, we discuss the completeness of the velocity catalogue, the morphology of the supercluster, the global overdensity, and some properties of the individual galaxy clusters in the Supercluster.
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    The shapley supercluster. III. Collapse dynamics and mass of the central concentration
    (2000) Reisenegger, A.; Quintana, H.; Carrasco, E.R.; Maze, J.
    We present the first application of a spherical collapse model to a supercluster of galaxies. Positions and redshifts of similar to 3000 galaxies in the Shapley supercluster (SSC) are used to define velocity caustics that limit the gravitationally collapsing structure in its central part. This is found to extend at least to 8 h(-1) Mpc of the central cluster, A3558, enclosing 11 ACO clusters. Infall velocities reach similar to 2000 km s(-1). Dynamical models of the collapsing region are used to estimate its mass profile. An upper bound on the mass, based on a pure spherical infall model, gives M(<8 h(-1) Mpc) less than or similar to 1.3 x 10(16) h(-1) M. for an Einstein-de Sitter (critical) universe and M(<8 h(-1) Mpc) less than or similar to 8.5 x 10(15) h(-1) M. for an empty universe. The Diaferio & Geller model, based on estimating the escape velocity, gives a significantly lower value, M(<8 h(-1) Mpc) approximate to 2.1 x 10(15) h(-1) M., very similar to the mass Geller et al. found around the Coma cluster by the same method and comparable to or slightly lower than the dynamical mass in the vriialized regions of clusters enclosed in the same region of the SSC. In both models, the overdensity in this region is substantial, but it is far from the value required to account for the peculiar motion of the Local Group with respect to the cosmic microwave background.