Planck early results V : The Low Frequency Instrument data processing

Peer reviewe

Planck early results III : First assessment of the Low Frequency Instrument in-flight performance

Peer reviewe

The x-ray polarimetry view of the accreting pulsar Cen X-3

Galaxie

Prolonged, low dose alpha-tocopherol therapy counteracts intercellular cell adhesion molecule-1 activation.

Up-regulation of ICAM-1 at the vascular endothelial level is one of the most important promoters in the slow progression of a healthy vessel to an atherosclerotic one. The current study aimed to evaluate whether low dose of the antioxidant alpha-tocopherol affects the circulating soluble (s) ICAM-1 in healthy subjects. Either alpha-tocopherol E (50 I.U./day) or placebo was randomly, double-blindly given to 39 healthy male volunteers (mean age 41.6+/-5.9 years) over a period of 20 weeks. At the baseline, sICAM-1 levels were inversely correlated with alpha-tocopherol concentrations (r=-0.525, p<0.0001). Twenty weeks of alpha-tocopherol supplementation (n=20 subjects) significantly decreased the circulating sICAM-1 levels (from 149.2+/-18.4 to 131.5+/-17.2 microg l(-1), p<0.004) while it increased the alpha-tocopherol concentrations (from 25.8+/-5.0 to 31.2+/-5.7 micromol l(-1), p<0.003). No significant changes in plasma sICAM-1 and alpha-tocopherol levels were observed in placebo-treated subjects (n=19). In actively treated subjects, changes in circulating sICAM-1 were inversely correlated with changes in alpha-tocopherol concentrations (r=-0.597, p=0.005). Plasma sICAM-1 concentrations are stable in healthy subjects over a period of 20 weeks while they significantly decreased with low dose of alpha-tocopherol. Thus, antioxidant vitamins are likely to counteract with endothelial changes that could potentially trigger the atherogenetic process

Determination of X-ray pulsar geometry with IXPE polarimetry

Galaxie

The x-ray polarimetry view of the accreting pulsar Cen X-3

Galaxie

Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer

International audienceWe report on the Imaging X-ray Polarimetry Explorer (IXPE) observation of the closest and X-ray brightest Compton-thick active galactic nucleus (AGN), the Circinus galaxy. We find the source to be significantly polarized in the 2-6 keV band. From previous studies, the X-ray spectrum is known to be dominated by reflection components, both neutral (torus) and ionized (ionization cones). Our analysis indicates that the polarization degree is 28 ± 7 per cent (at 68 per cent confidence level) for the neutral reflector, with a polarization angle of 18○ ± 5○, roughly perpendicular to the radio jet. The polarization of the ionized reflection is unconstrained. A comparison with Monte Carlo simulations of the polarization expected from the torus shows that the neutral reflector is consistent with being an equatorial torus with a half-opening angle of 45○-55○. This is the first X-ray polarization detection in a Seyfert galaxy, demonstrating the power of X-ray polarimetry in probing the geometry of the circumnuclear regions of AGNs, and confirming the basic predictions of standard Unification Models

XIPE

XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially-resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics. Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega launcher. XIPE is designed as an observatory for X-ray astronomers with 75 % of the time dedicated to a Guest Observer competitive program and it is organized as a consortium across Europe with main contributions from Italy, Germany, Spain, United Kingdom, Poland, Sweden.Peer reviewe

Euclid. I. Overview of the Euclid mission

International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance