X-ray astronomy in the new Millenium. A Summary

Recent X-ray observations have had a major impact on topics ranging from protostars to cosmology. They have also drawn attention to important and general physical processes that currently limit our understanding of thermal and nonthermal X-ray sources. These include unmeasured atomic astrophysics data (wavelengths, oscillator strengths etc.), basic hydromagnetic processes (e.g. shock structure, reconnection), plasma processes (such as electron-ion equipartition and heat conduction) and radiative transfer (in disks and accretion columns). Progress on these problems will probably come from integrative studies that draw upon observations, throughout the electromagnetic spectrum, of different classes of source. X-ray observations are also giving a new perspective on astronomical subjects, like the nature of galactic nuclei and the evolution of stellar populations. They are contributing to answering central cosmological questions including the measurement of the matter content of the universe, understanding its overall luminosity density, describing its chemical evolution and locating the first luminous objects. X-ray astronomy has a healthy future with several international space missions under construction and in development.Comment: 12 page

Suppression of Upsilon(1S) at forward rapidity in Pb-Pb collisions at root s(NN)=2.76 TeV

We report on the measurement of the inclusive Upsilon(1S) production in Pb-Pb collisions at root s(NN) = 2.76 TeV carried out at forward rapidity (2.5 < y < 4) and down to zero transverse momentum using its mu(+)mu(-) decay channel with the ALICE detector at the Large Hadron Collider. Astrong suppression of the inclusive Upsilon(1S) yield is observed with respect to pp collisions scaled by the number of independent nucleo-nnucleon collisions. The nuclear modification factor, for events in the 0-90% centrality range, amounts to 0.30 +/- 0.05(stat) +/- 0.04(syst). The observed Upsilon(1S) suppression tends to increase with the centrality of the collision and seems more pronounced than in corresponding mid-rapidity measurements. Our results are compared with model calculations, which are found to underestimate the measured suppression and fail to reproduce its rapidity dependence. (C) 2014 The Authors. Published by Elsevier B. V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). Funded by SCOAP(3)

Measurement of visible cross sections in proton-lead collisions at 1asNN= 5.02 TeV in van der Meer scans with the ALICE detector

In 2013, the Large Hadron Collider provided proton-lead and lead-proton collisions at the center-of-mass energy per nucleon pair root s NN=5.02 TeV . Van der Meer scans were performed for both configurations of colliding beams, and the cross section was measured for two reference processes, based on particle detection by the T0 and V0 detectors, with pseudo-rapidity coverage 4.6 < \u3b7 < 4.9, -3.3 < \u3b7 < -3.0 and 2.8 < \u3b7 < 5.1, -3.7 < \u3b7 < -1.7, respectively. Given the asymmetric detector acceptance, the cross section was measured separately for the two configurations. The measured visible cross sections are used to calculate the integrated luminosity of the proton-lead and lead-proton data samples, and to indirectly measure the cross section for a third, configuration-independent, reference process, based on neutron detection by the Zero Degree Calorimeters