A Multiband Study of the Galaxy Populations of the First Four Sunyaev--Zeldovich Effect selected Galaxy Clusters

We present first results of an examination of the optical properties of the galaxy populations in SZE selected galaxy clusters. Using clusters selected by the South Pole Telescope survey and deep multiband optical data from the Blanco Cosmology Survey, we measure the radial profile, the luminosity function, the blue fraction and the halo occupation number of the galaxy populations of these four clusters with redshifts ranging from 0.3 to 1. Our goal is to understand whether there are differences among the galaxy populations of these SZE selected clusters and previously studied clusters selected in the optical and the X-ray. The radial distributions of galaxies in the four systems are consistent with NFW profiles with a galaxy concentration of 3 to 6. We show that the characteristic luminosities in $griz$ bands are consistent with passively evolving populations emerging from a single burst at redshift $z=3$. The faint end power law slope of the luminosity function is found to be on average $\alpha \approx -1.2$ in griz. Halo occupation numbers (to $m^*+2$) for these systems appear to be consistent with those based on X-ray selected clusters. The blue fraction estimated to $0.36L^*$, for the three lower redshift systems, suggests an increase with redshift, although with the current sample the uncertainties are still large. Overall, this pilot study of the first four clusters provides no evidence that the galaxy populations in these systems differ significantly from those in previously studied cluster populations selected in the X-ray or the optical.Comment: 12 pages, 12 figures and 3 tables. Accepted for publication in Ap

A Review of High School Level Astronomy Student Research Projects over the last two decades

Since the early 1990s with the arrival of a variety of new technologies, the capacity for authentic astronomical research at the high school level has skyrocketed. This potential, however, has not realized the bright-eyed hopes and dreams of the early pioneers who expected to revolutionise science education through the use of telescopes and other astronomical instrumentation in the classroom. In this paper, a general history and analysis of these attempts is presented. We define what we classify as an Astronomy Research in the Classroom (ARiC) project and note the major dimensions on which these projects differ before describing the 22 major student research projects active since the early 1990s. This is followed by a discussion of the major issues identified that affected the success of these projects and provide suggestions for similar attempts in the future.Comment: Accepted for Publication in PASA. 26 page

Towards the Chalonge 16th Paris Cosmology Colloquium 2012: Highlights and Conclusions of the Chalonge 15th Paris Cosmology Colloquium 2011

The Chalonge 15th Paris Cosmology Colloquium 2011 was held on 20-22 July in the historic Paris Observatory's Perrault building, in the Chalonge School spirit combining real cosmological/astrophysical data and hard theory predictive approach connected to them in the Warm Dark Matter Standard Model of the Universe: News and reviews from Herschel, QUIET, Atacama Cosmology Telescope (ACT), South Pole Telescole (SPT), Planck, PIXIE, the JWST, UFFO, KATRIN and MARE experiments; astrophysics, particle and nuclear physics warm dark matter (DM) searches and galactic observations, related theory and simulations, with the aim of synthesis, progress and clarification. Philippe Andre, Peter Biermann, Pasquale Blasi, Daniel Boyanovsky, Carlo Burigana, Hector de Vega, Joanna Dunkley, Gerry Gilmore, Alexander Kashlinsky, Alan Kogut, Anthony Lasenby, John Mather, Norma Sanchez, Alexei Smirnov, Sylvaine Turck-Chieze present here their highlights of the Colloquium. Ayuki Kamada and Sinziana Paduroiu present here their poster highlights. LambdaWDM (Warm Dark Matter) is progressing impressively over LambdaCDM whose galactic scale crisis and decline are staggering. The International School Daniel Chalonge issued an statement of strong support to the James Webb Space Telescope (JSWT). The Daniel Chalonge Medal 2011 was awarded to John C. Mather, Science PI of the JWST. Summary and conclusions are presented by H. J. de Vega, M. C. Falvella and N. G. Sanchez. Overall, LambdaWDM and keV scale DM particles deserve dedicated astronomical and laboratory experimental searches, theoretical work and simulations. KATRIN experiment in the future could perhaps adapt its set-up to look to keV scale sterile neutrinos. It will be a a fantastic discovery to detect dark matter in a beta decay. Photos of the Colloquium are included. (Abridged)Comment: 65 pages, 21 figure

The zCOSMOS 20k Group Catalog

We present an optical group catalog between 0.1 < z < 1 based on 16,500 high-quality spectroscopic redshifts in the completed zCOSMOS-bright survey. The catalog published herein contains 1498 groups in total and 192 groups with more than five observed members. The catalog includes both group properties and the identification of the member galaxies. Based on mock catalogs, the completeness and purity of groups with three and more members should be both about 83% with respect to all groups that should have been detectable within the survey, and more than 75% of the groups should exhibit a one-to-one correspondence to the "real" groups. Particularly at high redshift, there are apparently more galaxies in groups in the COSMOS field than expected from mock catalogs. We detect clear evidence for the growth of cosmic structure over the last seven billion years in the sense that the fraction of galaxies that are found in groups (in volume-limited samples) increases significantly with cosmic time. In the second part of the paper, we develop a method for associating galaxies that only have photo-z to our spectroscopically identified groups. We show that this leads to improved definition of group centers, improved identification of the most massive galaxies in the groups, and improved identification of central and satellite galaxies, where we define the former to be galaxies at the minimum of the gravitational potential wells. Subsamples of centrals and satellites in the groups can be defined with purities up to 80%, while a straight binary classification of all group and non-group galaxies into centrals and satellites achieves purities of 85% and 75%, respectively, for the spectroscopic sample.Comment: 26 pages, 21 figures, published in ApJ (along with machine-readable tables