Relativistic heavy-ion physics

The study of relativistic heavy-ion collisions is an important part of the LHC research programme at CERN. This emerging field of research focuses on the study of matter under extreme conditions of temperature, density, and pressure. Here we present an introduction to the general aspects of relativistic heavy-ion physics. Afterwards we give an overview of the accelerator facility at CERN and then a quick look at the ALICE project as a dedicated experiment for heavy-ion collisions.Comment: 23 pages, Lectures given at the 5th CERN-Latin-American School of High-Energy Physics, Recinto Quirama, Colombia, 15 - 28 Mar 200

XMMPZCAT: A catalogue of photometric redshifts for X-ray sources

The third version of the XMM-Newton serendipitous catalogue (3XMM), containing almost half million sources, is now the largest X-ray catalogue. However, its full scientific potential remains untapped due to the lack of distance information (i.e. redshifts) for the majority of its sources. Here we present XMMPZCAT, a catalogue of photometric redshifts (photo-z) for 3XMM sources. We searched for optical counterparts of 3XMM-DR6 sources outside the Galactic plane in the SDSS and Pan-STARRS surveys, with the addition of near- (NIR) and mid-infrared (MIR) data whenever possible (2MASS, UKIDSS, VISTA-VHS, and AllWISE). We used this photometry data set in combination with a training sample of 5157 X-ray selected sources and the MLZ-TPZ package, a supervised machine learning algorithm based on decision trees and random forests for the calculation of photo-z. We have estimated photo-z for 100,178 X-ray sources, about 50% of the total number of 3XMM sources (205,380) in the XMM-Newton fields selected to build this catalogue (4208 out of 9159). The accuracy of our results highly depends on the available photometric data, with a rate of outliers ranging from 4% for sources with data in the optical+NIR+MIR, up to $\sim$40% for sources with only optical data. We also addressed the reliability level of our results by studying the shape of the photo-z probability density distributions.Comment: 16 pages, 14 figures, A&A accepte

The ALICE experiment at the LHC: a status review

ALICE is one of the big experiments at the LHC. It focuses on the study of heavy ion collisions at ultra-relativistic energies. Its main goal is to observe a transition of ordinary matter into a plasma of quarks and gluons. Here we review the status of the experiment just before data taking starts. Cosmic ray studies as well as the results of the past beam tests show the potential of the detector

The XMM-Newton spectral-fit database

The XMM-Newton spectral-fit database is an ongoing ESA funded project aimed to construct a catalogue of spectral-fitting results for all the sources within the XMM-Newton serendipitous source catalogue for which spectral data products have been pipeline-extracted (~ 120,000 X-ray source detections). The fundamental goal of this project is to provide the astronomical community with a tool to construct large and representative samples of X-ray sources by allowing source selection according to spectral properties.Comment: Conference proceedings of IAU Symposium 304: Multiwavelength AGN surveys and studie

Relativistic reflection in the average X-ray spectrum of AGN in the V\'eron-Cetty & V\'eron catalogue

The X-ray spectra of active galactic nuclei (AGN) unveil properties of matter around the super massive black hole (SMBH). We investigate the X-ray spectra of AGN focusing on Compton reflection and fluorescence, important processes of interaction between primary radiation and circum-nuclear material. Unresolved emission lines (most notably the Fe line) in the X-ray spectra of AGN indicate that this material is located far away from the SMBH. Contributions from the inner accretion disk, affected by relativistic effects, have also been detected in several cases. We studied the average X-ray spectrum of a sample of 263 X-ray unabsorbed AGN that yield 419023 counts in the 2-12 keV rest-frame band distributed among 388 XMM-Newton spectra. We fitted the average spectrum using a (basically) unabsorbed power law (primary radiation). From second model that represents the interaction of the primary radiation with matter located far away from the SMBH, we found that it was very significantly detected. Finally, we added a contribution from interaction with neutral material in the accretion disk close to the central SMBH, which is therefore smeared by relativistic effects, which improved the fit at 6 sigma. The reflection factors are 0.65 for the accretion disk and 0.25 for the torus. Replacing the neutral disk-reflection with low-ionisation disk reflection, also relativistically smeared, fits the data equally well, suggesting that we do not find evidence for a significant ionisation of the accretion disk. We detect distant neutral reflection in the average spectrum of unabsorbed AGN with z=0.8. Adding the disk-reflection component associated with a relativistic Fe line improves the data description at 6 sigma confidence level, suggesting that both reflection components are present. The disk-reflection component accounts for about 70 % of the total reflected flux.Comment: Accepted by A&A. 10 pages, 7 figure

Compton Thick AGN in the 70 Month Swift-BAT All-Sky Hard X-ray Survey: a Bayesian approach

The 70-month Swift/BAT catalogue provides a sensitive view of the extragalactic X-ray sky at hard energies (>10 keV) containing about 800 Active Galactic Nuclei. We explore its content in heavily obscured, Compton-thick AGN by combining the BAT (14-195 keV) with the lower energy XRT (0.3-10 keV) data. We apply a Bayesian methodology using Markov chains to estimate the exact probability distribution of the column density for each source. We find 53 possible Compton-thick sources (with probability 3 to 100%) translating to a ~7% fraction of the AGN in our sample. We derive the first parametric luminosity function of Compton-thick AGN. The unabsorbed luminosity function can be represented by a double power-law with a break at $L_{\star} 2 \times 10^{42}$ $\rm ergs~s^{-1}$ in the 20-40 keV band.Comment: 13 pages, 9 figure

Emergent Concepts on Knowledge Intensive Processes

An approach to refine and revise the general framework of KiP (Knowledge Intensive Process) is presented. The specific case of collaborative KiP is studied and the prominent role of collaborative KiPs in the general context of Business Processes is revealed. The approach is based on Formal Concept Analysis.Junta de Andalucía TIC-606

La disputa sociopolítica del excedente : Un estudio sobre el Estado y las organizaciones corporativas del trabajo en torno al Impuesto a las Ganancias

Durante el último lustro tanto en Argentina como en distintos países de la región latinoamericana se han experimentado un conjunto de transformaciones en diversas dimensiones políticas, sociales y económicas que marcaron un viraje en relación al proceso político neoliberal que caracterizó desde los años 70, pero principalmente en los años 90, su matriz societal. En esta dirección, una serie de trabajos y análisis de índole académica y periodística tienden a demarcar aspectos tanto de transformación como de persistencia de aquellas condiciones que apuntaron la singularidad del proceso neoliberal y sus alteraciones, virajes, y/o sedimentaciones en el último lustro. Con esta orientación, algunos términos y nociones conceptuales, teóricas y sobre todo de discusión política que habían sido relegadas en la agenda pública y mediática retornaron con diversa fortaleza de la mano de actores sociales y de gobierno dinamizando debates y situaciones de conflicto tanto retórico-narrativo como en la proliferación de protestas y movilizaciones sociales.Mesa 14: Acumulación, dominación y lucha de clases en la Argentina reciente (1989-2014)Facultad de Humanidades y Ciencias de la Educació