Fermi-LAT and Suzaku Observations of the Radio Galaxy Centaurus B

Centaurus B is a nearby radio galaxy positioned in the Southern hemisphere close to the Galactic plane. Here we present a detailed analysis of about 43 months of accumulated Fermi-LAT data of the gamma-ray counterpart of the source initially reported in the 2nd Fermi-LAT catalog, and of newly acquired Suzaku X-ray data. We confirm its detection at GeV photon energies, and analyze the extension and variability of the gamma-ray source in the LAT dataset, in which it appears as a steady gamma-ray emitter. The X-ray core of Centaurus B is detected as a bright source of a continuum radiation. We do not detect however any diffuse X-ray emission from the known radio lobes, with the provided upper limit only marginally consistent with the previously claimed ASCA flux. Two scenarios that connect the X-ray and gamma-ray properties are considered. In the first one, we assume that the diffuse non-thermal X-ray emission component is not significantly below the derived Suzaku upper limit. In this case, modeling the inverse-Compton emission shows that the observed gamma-ray flux of the source may in principle be produced within the lobes. This association would imply that efficient in-situ acceleration of the radiating electrons is occurring and that the lobes are dominated by the pressure from the relativistic particles. In the second scenario, with the diffuse X-ray emission well below the Suzaku upper limits, the lobes in the system are instead dominated by the magnetic pressure. In this case, the observed gamma-ray flux is not likely to be produced within the lobes, but instead within the nuclear parts of the jet. By means of synchrotron self-Compton modeling we show that this possibility could be consistent with the broad-band data collected for the unresolved core of Centaurus B, including the newly derived Suzaku spectrum.Comment: Accepted for publication in A&A. 11 page

Comparison of the efficacy of rosuvastatin versus atorvastatin in reducing apolipoprotein B/apolipoprotein A-1 ratio in patients with acute coronary syndrome: Results of the CENTAURUS study

Background. The mechanism underlying statin-induced event reduction in patients with acute coronary syndrome remains unclear. Aims. To assess the efficacy of rosuvastatin 20 mg versus atorvastatin 80 mg in reducing the apolipoprotein B/apolipoprotein A-1 (apoB/apoA-1) ratio at 3 months. Non-inferiority of rosuvastatin 20 mg versus atorvastatin 80 mg in reducing low-density lipoprotein cholesterol at 1 and 3 months was also assessed. Methods. Patients with non-ST-elevation acute coronary syndrome were enrolled into this randomized, double blind, parallel-group trial. Results. In total, 753 patients (369, rosuvastatin 20 mg; 384, atorvastatin 80 mg) were included in the intention-to-treat analysis; 478 patients (226, rosuvastatin 20 mg; 252, atorvastatin 80 mg) were included in the per-protocol analysis. Rosuvastatin 20 mg was more effective than atorvastatin 80 mg in decreasing apoB/apoA-1 ratio at 1 month (-44.4% vs -42.9%, p = 0.02) but not at 3 months (both -44.4%, p = 0.87). Low-density lipoprotein cholesterol decreased by similar to 50% after 1 and 3 months in both groups. Non-inferiority of rosuvastatin 20 mg versus atorvastatin 80 mg was demonstrated at 1 month (difference, -0.3% [95% confidence interval, -2.7; +2.1]), but not at 3 months (+1.0% [-1.6; 3.5]) (intention-to-treat analysis). In the per-protocol analysis, non-inferiority of rosuvastatin 20 mg was demonstrated at both 1 (-0.7% [-3.5; 2.0]) and 3 (-0.5% [-3.5; 2.5]) months. Conclusion. In patients with non-ST-elevation acute coronary syndrome, rosuvastatin 20 mg decreased apoB/apoA-1 ratio at 1 month more than atorvastatin 80 mg. No difference could be shown at 3 months; thus, the primary endpoint was not met. (C) 2010 Published by Elsevier Masson SAS