2,546 research outputs found
INTEGRAL: science highlights and future prospects
ESA's hard X-ray and soft gamma-ray observatory INTEGRAL is covering the 3
keV to 10 MeV energy band, with excellent sensitivity during long and
uninterrupted observations of a large field of view (~100 square degrees), with
ms time resolution and keV energy resolution. It links the energy band of
pointed soft X-ray missions such as XMM-Newton with that of high-energy
gamma-ray space missions such as Fermi and ground based TeV observatories. Key
results obtained so far include the first sky map in the light of the 511 keV
annihilation emission, the discovery of a new class of high mass X-ray binaries
and detection of polarization in cosmic high energy radiation. For the
foreseeable future, INTEGRAL will remain the only observatory allowing the
study of nucleosynthesis in our Galaxy, including the long overdue next nearby
supernova, through high-resolution gamma-ray line spectroscopy. Science results
to date and expected for the coming mission years span a wide range of
high-energy astrophysics, including studies of the distribution of positrons in
the Galaxy; reflection of gamma-rays off clouds in the interstellar medium near
the Galactic Centre; studies of black holes and neutron stars particularly in
high- mass systems; gamma-ray polarization measurements for X-ray binaries and
gamma-ray bursts, and sensitive detection capabilities for obscured active
galaxies with more than 1000 expected to be found until 2014. This paper
summarizes scientific highlights obtained since INTEGRAL's launch in 2002, and
outlines prospects for the INTEGRAL mission.Comment: 39 pages, accepted, 24 October 2011, Space Science Review
The INTEGRAL Core Observing Programme
The Core Programme of the INTEGRAL mission is defined as the portion of the
scientific programme covering the guaranteed time observations for the INTEGRAL
Science Working Team. This paper describes the current status of the Core
Programme preparations and summarizes the key elements of the observing
programme.Comment: Contributed paper, 3rd INTEGRAL Workshop, Taormina/Sicily, Sep 1998,
to be published in Astrophys. Letters & Communications, 199
Swift/XRT- NuSTAR spectra of type 1 AGN]{Swift/XRT- NuSTAR spectra of type 1 AGN: confirming INTEGRAL results on the high energy cut-off
We present the 0.5 - 78 keV spectral analysis of 18 broad line AGN belonging
to the INTEGRAL complete sample. Using simultaneous Swift-XRT and NuSTAR
observations and employing a simple phenomenological model to fit the data, we
measure with a good constraint the high energy cut-off in 13 sources, while we
place lower limits on 5 objects. We found a mean high-energy cut-off of 111 keV
(standard deviation = 45 keV) for the whole sample, in perfect agreement with
what found in our previous work using non simultaneous observations and with
what recently published using NuSTAR data. This work suggests that simultaneity
of the observations in the soft and hard X-ray band is important but not always
essential, especially if flux and spectral variability are properly accounted
for. A lesser agreement is found when we compare our cut-off measurements with
the ones obtained by Ricci et al. (2017) using Swift-BAT high energy data,
finding that their values are systematically higher than ours. We have
investigated whether a linear correlation exists between photon index and the
cut-off and found a weak one, probably to be ascribed to the non perfect
modelling of the soft part of the spectra, due to the poor statistical quality
of the 2-10 keV X-ray data. No correlation is also found between the Eddington
ratio and the cut-off, suggesting that only using high statistical quality
broad-band spectra is it possible to verify the theoretical predictions and
study the physical characteristics of the hot corona and its geometry.Comment: 12 pages, 11 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Societ
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