Search results for "Astrophysical"
showing 10 items of 4966 documents
Modeling an X-ray Flare on Proxima Centauri: evidence of two flaring loop components and of two heating mechanisms at work
2003
We model in detail a flare observed on Proxima Centauri with the EPIC-PN on board XMM-Newton at high statistics and high time resolution and coverage. Time-dependent hydrodynamic loop modeling is used to describe the rise and peak of the light curve, and a large fraction of the decay, including its change of slope and a secondary maximum, over a duration of more than 2 hours. The light curve, the emission measure and the temperature derived from the data allow us to constrain the loop morphology and the heating function and to show that this flare can be described with two components: a major one triggered by an intense heat pulse injected in a single flaring loop with half-length ~1.0 10^{…
"Table 12" of "Search for heavy resonances decaying to a photon and a hadronically decaying $Z/W/H$ boson in $pp$ collisions at $\sqrt{s}=13$ $\mathr…
2018
Distribution of the reconstructed J+gamma invariant mass in W+gamma search ELSE category.
"Table 10" of "Search for heavy resonances decaying to a photon and a hadronically decaying $Z/W/H$ boson in $pp$ collisions at $\sqrt{s}=13$ $\mathr…
2018
Distribution of the reconstructed J+gamma invariant mass in W+gamma search D2 category.
"Table 11" of "Search for heavy resonances decaying to a photon and a hadronically decaying $Z/W/H$ boson in $pp$ collisions at $\sqrt{s}=13$ $\mathr…
2018
Distribution of the reconstructed J+gamma invariant mass in W+gamma search VMASS category.
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
2023
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (i…
B-MINE, the balloon-borne microcalorimeter nuclear line explorer
2001
B-MINE is a concept for a balloon mission designed to probe the deepest regions of a supernova explosion by detecting Ti-44 emission at 68 keV with spatial and spectral resolutions that are sufficient to determine the extent and velocity distribution of the Ti-44 emitting region. The payload introduces the concept of focusing optics and microcalorimeter spectroscopy to nuclear line emission astrophysics. B-MINE has a thin, plastic foil telescope multilayered to maximize the reflectivity in a 20 keV band centered at 68 keV and a microcalorimeter array optimized for the same energy band. This combination provides a reduced background, an energy resolution of 50 eV and a 3sigma sensitivity in …
Electronic structure of single-crystal rocksalt CdO studied by soft x-ray spectroscopies andab initiocalculations
2008
Soft x-ray emission spectroscopy (XES) and x-ray absorption spectroscopy (XAS) are employed to investigate the occupied and unoccupied electronic structures in rocksalt-phase single-crystal CdO. Resonant XES at the OK edge reveals a clear Cd 4d-O 2p hybridized peak and momentum-dependent coherent contributions to the resonant emission spectra. Good agreement is obtained between the above-threshold XES and XAS spectra, and the calculated O 2p local partial density of states (PDOS). Calculation of the O 2p PDOS was performed within the GW framework of many-body perturbation theory.
Broadband observations of the X-ray burster 4U1705-44 with Beppo SAX
2016
4U 1705-44 is one of the most-studied type I X-ray burster and Atoll sources. This source represents a perfect candidate to test different models proposed to self-consistently track the physical changes occurring between different spectral states because it shows clear spectral state transitions. The broadband coverage, the sensitivity and energy resolution of the BeppoSAX satellite offers the opportunity to disentangle the components that form the total X-ray spectrum and to study their changes according to the spectral state. Using two BeppoSAX observations carried out in August and October 2000, respectively, for a total effective exposure time of about 100 ks, we study the spectral evol…
EBIT diagnostics using X-ray spectra of highly ionized Ne
2003
We have carried out a detailed analysis of highly ionized neon spectra collected at the NIST EBIT using an NTD germanium X-ray microcalorimeter developed at the Harvard-Smithsonian Center for Astrophysics [Nucl. Instr. and Meth. A 444 (2000) 156]. Our attention was focused especially on the Ne IX He-like triplet to check electron density diagnostics through the intercombination/forbidden line ratio. We have investigated possible effects of the ion dynamics on the plasma emission line intensities, looking at the dependence of the count-rate and the charge state distribution on the electron beam energy and current. The temperature and spatial distribution of the neon ions, and hence the overl…
The LOFT mission concept: a status update
2016
The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT will be able to study the behaviour of matter in extreme conditions such as the strong gravitational field in the innermost regions close to black holes and neutron stars and the supra-nuclear densities in the interiors of neutron stars. The science payload is based on a Large Area Detector (LAD, >8m2 effective area, 2-30 keV, 240 eV spectral resolut…