-
M. Feroci,
J. W. den Herder,
E. Bozzo,
D. Barret,
S. Brandt,
M. Hernanz,
M. van der Klis,
M. Pohl,
A. Santangelo,
L. Stella, [......],
D. Lai,
F. K. Lamb,
F. Lebrun,
D. Lin,
D. Linder,
G. Lodato,
F. Longo,
N. Lund,
T. J. Maccarone,
D. Macera
-
M. Tavani,
G. Barbiellini,
A. Argan,
A. Bulgarelli,
P. Caraveo,
A. Chen,
V. Cocco,
E. Costa,
G. De Paris,
E. Del Monte, [......],
P. Soffitta,
M. Trifoglio,
A. Trois,
E. Vallazza,
S. Vercellone,
A. Zambra,
D. Zanello,
P. Giommi, A. Antonelli,
C. Pittori
-
M. Tavani,
G. Barbiellini,
A. Argan,
A. Bulgarelli,
P. Caraveo,
A. Chen,
V. Cocco,
E. Costa,
G. De Paris,
E. Del Monte, [......],
P. Soffitta,
M. Trifoglio,
A. Trois,
E. Vallazza,
S. Vercellone,
A. Zambra,
D. Zanello,
P. Giommi, A. Antonelli,
C. Pittori
-
M. Feroci,
J. W. den Herder,
E. Bozzo,
D. Barret,
S. Brandt,
M. Hernanz,
M. van der Klis,
M. Pohl,
A. Santangelo,
L. Stella, [......],
R. Wijnands,
M. Wille,
C. A. Wilson-Hodge,
B. Winter,
K. Wood,
G. Zampa,
N. Zampa,
L. Zampieri,
A. Zdziarski,
B. Zhang
[show abstract]
[hide abstract]
ABSTRACT: The LOFT mission concept is one of four candidates selected by ESA for the M3
launch opportunity as Medium Size missions of the Cosmic Vision programme. The
launch window is currently planned for between 2022 and 2024. LOFT is designed
to exploit the diagnostics of rapid X-ray flux and spectral variability that
directly probe the motion of matter down to distances very close to black holes
and neutron stars, as well as the physical state of ultra-dense matter. These
primary science goals will be addressed by a payload composed of a Large Area
Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a collimated (<1
degree field of view) experiment operating in the energy range 2-50 keV, with a
10 m^2 peak effective area and an energy resolution of 260 eV at 6 keV. The WFM
will operate in the same energy range as the LAD, enabling simultaneous
monitoring of a few-steradian wide field of view, with an angular resolution of
<5 arcmin. The LAD and WFM experiments will allow us to investigate variability
from submillisecond QPO's to year-long transient outbursts. In this paper we
report the current status of the project.
09/2012;
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F. Ambrosino,
B. Angelucci, A. Antonelli,
F. Costantini,
G. D'Agostini,
D. Di Filippo,
R. Fantechi,
S. Gallorini,
S. Giudici,
E. Leonardi, [......],
M. Moulson,
M. Napolitano,
V. Palladino,
F. Rafaelli,
M. Raggi,
G. Saracino,
M. Serra,
T. Spadaro,
P. Valente,
S. Venditti
[show abstract]
[hide abstract]
ABSTRACT: The branching ratio (BR) for the decay K^+ \to \pi^+\nu\bar{\nu} is a
sensitive probe for new physics. The NA62 experiment at the CERN SPS will
measure this BR to within about 10%. To reject the background from dominant
kaon decays with final state photons, the large-angle photon vetoes (LAVs) must
detect photons of energy as low as 200 MeV with an inefficiency of less than
10^{-4}. The LAV detectors make use of lead glass blocks recycled from the OPAL
electromagnetic calorimeter barrel. We describe the mechanical design and
challenges faced during construction, the characterization of the lead glass
blocks and solutions adopted for monitoring their performance, and the
development of front-end electronics to allow simultaneous time and energy
measurements over an extended dynamic range using the time over-threshold
technique. Our results are based on test-beam data and are reproduced by a
detailed Monte Carlo simulation that includes the readout chain.
07/2012;
-
A. Antonelli,
G. Corradi,
M. Moulson,
C. Paglia,
M. Raggi,
T. Spadaro,
D. Tagnani,
F. Ambrosino,
D. Di Filippo,
P. Massarotti, [......],
S. Gallorini,
S. Giudici,
I. Mannelli,
F. Raffaelli,
S. Venditti,
G. D'Agostini,
E. Leonardi,
V. Palladino,
M. Serra,
P. Valente
[show abstract]
[hide abstract]
ABSTRACT: The branching ratio for the decay $K^+ \to \pi^+\nu\bar{\nu}$ is sensitive to
new physics; the NA62 experiment will measure it to within about 10%. To reject
the dominant background from channels with final state photons, the large-angle
vetoes (LAVs) must detect particles with better than 1 ns time resolution and
10% energy resolution over a very large energy range. Our custom readout board
uses a time-over-threshold discriminator coupled to a TDC as a straightforward
solution to satisfy these requirements. A prototype of the readout system was
extensively tested together with the ANTI-A2 large angle veto module at CERN in
summer 2010.
11/2011;
-
M. Garczarczyk, A. Antonelli,
D. Bastieri,
J. Becerra‐González,
A. Carosi,
S. Covino,
A. Dominguez,
M. Gaug,
A. La Barbera,
F. Longo,
V. Scapin,
S. Spiro
[show abstract]
[hide abstract]
ABSTRACT: MAGIC is built to perform observations of prompt and early afterglow emission from Gamma‐Ray Bursts (GRBs) above 25 GeV. The instrument is designed to have the lowest possible energy threshold among the ground based γ‐ray detectors and the fastest reaction time to alerts distributed over the GRB Coordinates Network (GCN). The MAGIC‐I telescope observed 57 GRBs during the first six years. In no cases Very High Energy (VHE) γ‐ray emission above the threshold energy could be detected. The telescope has undergone several major improvements in sensitivity and repositioning performance. The biggest improvement in sensitivity was achieved with the installation of the second MAGIC‐II telescope. Since more than one year both telescopes are observing in stereo mode. MAGIC are the only telescopes fast and sensitive enough to extend the observational energy range of satellite detectors, while GRB prompt and early afterglow emission is still ongoing.
AIP Conference Proceedings. 10/2010; 1279(1):312-314.
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A Pellizzoni,
A Trois,
M Tavani,
M Pilia,
A Giuliani,
G Pucella,
P Esposito,
S Sabatini,
G Piano,
A Argan, [......],
F Verrecchia,
V Vittorini,
A Zambra,
D Zanello,
P Giommi,
S Colafrancesco, A Antonelli,
L Salotti,
N D'Amico,
G F Bignami
[show abstract]
[hide abstract]
ABSTRACT: Pulsars are known to power winds of relativistic particles that can produce bright nebulae by interacting with the surrounding medium. These pulsar wind nebulae are observed by their radio, optical, and x-ray emissions, and in some cases also at TeV (teraelectron volt) energies, but the lack of information in the gamma-ray band precludes drawing a comprehensive multiwavelength picture of their phenomenology and emission mechanisms. Using data from the AGILE satellite, we detected the Vela pulsar wind nebula in the energy range from 100 MeV to 3 GeV. This result constrains the particle population responsible for the GeV emission and establishes a class of gamma-ray emitters that could account for a fraction of the unidentified galactic gamma-ray sources.
Science 02/2010; 327(5966):663-5. · 31.20 Impact Factor
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M Tavani,
A Bulgarelli,
G Piano,
S Sabatini,
E Striani,
Y Evangelista,
A Trois,
G Pooley,
S Trushkin,
N A Nizhelskij, [......],
S Vercellone,
A Zambra,
D Zanello,
C Pittori,
F Verrecchia,
P Giommi,
S Colafrancesco,
P Santolamazza, A Antonelli,
L Salotti
[show abstract]
[hide abstract]
ABSTRACT: Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated gamma-ray emission. Galactic 'microquasars', which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four gamma-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the gamma-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states.
Nature 11/2009; 462(7273):620-3. · 36.28 Impact Factor
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M. Tavani,
A. Bulgarelli,
G. Piano,
S. Sabatini,
E. Striani,
Y. Evangelista,
A. Trois,
G. Pooley,
S. Trushkin,
N. A. Nizhelskij, [......],
S. Vercellone,
A. Zambra,
D. Zanello,
C. Pittori,
F. Verrecchia,
P. Giommi,
S. Colafrancesco,
P. Santolamazza, A Antonelli,
L. Salotti
[show abstract]
[hide abstract]
ABSTRACT: The study of relativistic particle acceleration is a major topic of high-energy astrophysics. It is well known that massive black holes in active galaxies can release a substantial fraction of their accretion power into energetic particles, producing gamma-rays and relativistic jets. Galactic microquasars (hosting a compact star of 1-10 solar masses which accretes matter from a binary companion) also produce relativistic jets. However, no direct evidence of particle acceleration above GeV energies has ever been obtained in microquasar ejections, leaving open the issue of the occurrence and timing of extreme matter energization during jet formation. Here we report the detection of transient gamma-ray emission above 100 MeV from the microquasar Cygnus X-3, an exceptional X-ray binary which sporadically produces powerful radio jets. Four gamma-ray flares (each lasting 1-2 days) were detected by the AGILE satellite simultaneously with special spectral states of Cygnus X-3 during the period mid-2007/mid-2009. Our observations show that very efficient particle acceleration and gamma-ray propagation out of the inner disk of a microquasar usually occur a few days before major relativistic jet ejections. Flaring particle energies can be thousands of times larger than previously detected maximum values (with Lorentz factors of 105 and 102 for electrons and protons, respectively). We show that the transitional nature of gamma-ray flares and particle acceleration above GeV energies in Cygnus X-3 is clearly linked to special radio/X-ray states preceding strong radio flares. Thus gamma-rays provide unique insight into the nature of physical processes in microquasars. Comment: 29 pages (including Supplementary Information), 8 figures, 2 tables version submitted to Nature on August 7, 2009 (accepted version available at http://www.nature.com/nature/journal/vaop/ncurrent/pdf/nature08578.pdf)
10/2009;
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M. Feroci,
E. Costa,
E. Del Monte,
I. Donnarumma,
Y. Evangelista,
I. Lapshov,
F. Lazzarotto,
L. Pacciani,
M. Rapisarda,
P. Soffitta, [......],
A. Traci,
M. Trifoglio,
A. Trois,
E Vallazza,
S. Vercellone,
F. Verrecchia,
V. Vittorini,
A. Zambra,
D. Zanello,
L. Salotti
[show abstract]
[hide abstract]
ABSTRACT: SuperAGILE is the hard X-ray monitor of the AGILE gamma ray mission, in orbit since 23$^{rd}$ April 2007. It is an imaging experiment based on a set of four independent silicon strip detectors, equipped with one-dimensional coded masks, operating in the nominal energy range 18-60 keV. The main goal of SuperAGILE is the observation of cosmic sources simultaneously with the main gamma-ray AGILE experiment, the Gamma Ray Imaging Detector (GRID). Given its $\sim$steradian-wide field of view and its $\sim$15 mCrab day-sensitivity, SuperAGILE is also well suited for the long-term monitoring of Galactic compact objects and the detection of bright transients. The SuperAGILE detector properties and design allow for a 6 arcmin angular resolution in each of the two independent orthogonal projections of the celestial coordinates. Photon by photon data are continuously available by the experiment telemetry, and are used to derive images and fluxes of individual sources, with integration times depending on the source intensity and position in the field of view. In this paper we report on the main scientific results achieved by SuperAGILE over its first two years in orbit, until April 2009. Comment: Accepted for publication on Astronomy & Astrophysics
10/2009;
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C. Pittori,
F. Verrecchia,
A. W. Chen,
A. Bulgarelli,
A. Pellizzoni,
A Giuliani,
S. Vercellone,
F. Longo,
M. Tavani,
P. Giommi, [......],
S. Stellato,
E. Striani,
F. Tamburelli,
A. Traci,
A. Trois,
E Vallazza,
V. Vittorini,
A. Zambra,
D. Zanello,
L. Salotti
[show abstract]
[hide abstract]
ABSTRACT: We present the first catalog of high-confidence gamma-ray sources detected by the AGILE satellite during observations performed from July 9, 2007 to June 30, 2008. Catalogued sources are detected by merging all the available data over the entire time period. AGILE, launched in April 2007, is an ASI mission devoted to gamma-ray observations in the 30 MeV - 50 GeV energy range, with simultaneous X-ray imaging capability in the 18-60 keV band. This catalog is based on Gamma-Ray Imaging Detector (GRID) data for energies greater than 100 MeV. For the first AGILE catalog we adopted a conservative analysis, with a high-quality event filter optimized to select gamma-ray events within the central zone of the instrument Field of View (radius of 40 degrees). This is a significance-limited (4 sigma) catalog, and it is not a complete flux-limited sample due to the non-uniform first year AGILE sky coverage. The catalog includes 47 sources, 21 of which are associated with confirmed or candidate pulsars, 13 with Blazars (7 FSRQ, 4 BL Lacs, 2 unknown type), 2 with HMXRBs, 2 with SNRs, 1 with a colliding-wind binary system, 8 with unidentified sources. Comment: Revised version, 15 pages, 3 figures, 3 tables. To be published in Astronomy and Astrophysics. Text improved and clarified. Refined analysis of complex regions of the Galactic plane yields a new list of high-confidence sources including 47 sources (compared with the 40 sources appearing in the first version)
02/2009;
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[show abstract]
[hide abstract]
ABSTRACT: After the launch and successful beginning of operations of the FERMI satellite, the topics related to high-energy observations of gamma-ray bursts have obtained a considerable attention by the scientific community. Undoubtedly, the diagnostic power of high-energy observations in constraining the emission processes and the physical conditions of gamma-ray burst is relevant. We briefly discuss how gamma-ray burst observations with ground-based imaging array Cerenkov telescopes, in the GeV-TeV range, can compete and cooperate with FERMI observations, in the MeV-GeV range, to allow researchers to obtain a more detailed and complete picture of the prompt and afterglow phases of gamma-ray bursts. Comment: 9 pages, two figures. Proceeding for the 6th "Science with the New Generation of High Energy Gamma-Ray Experiments" workshop
01/2009;
-
C. Labanti,
M. Tavani,
G. Barbiellini,
A. Argan,
F. Boffelli,
A. Bulgarelli,
P. Caraveo,
P. W. Cattaneo,
A. W. Chen,
V. Cocco, [......],
P. Giommi,
S. Colafrancesco,
C. Pittori,
B. Preger,
P. Santolamazza,
F. Verrecchia, A. Antonelli,
F. Viola,
G. Guarrera,
L. Salotti
[show abstract]
[hide abstract]
ABSTRACT: AGILE, an Italian Space Agency (ASI) mission dedicated to the exploration of the gamma-ray Universe, was successfully launched on April 23, 2007 from the Indian base of Sriharikota in an low-particle background equatorial orbit at 550 km height. AGILE gamma ray range cover the 30 MeV – 50 GeV band with its detectors combined together in the Gamma-Ray Imaging Detector (GRID). An X-ray imager (SuperAGILE) operates in the 18 – 60 keV band. Some of the payload instruments are also operated to detect transient X and gamma events with the main target being the Gamma Ray Burst in the SuperAGILE band and above 300 keV. The GRID instrument consists of a Silicon-Tungsten Tracker, a Caesium Iodide Mini-Calorimeter (MCAL), and a plastic-scintillator Anticoincidence system (ACS). The GRID achieves an angular resolution of about 15’ for bright sources with an unprecedented large field-of-view about 2.5 sr with a time resolution of few microsec and a very reduced dead-time (less than 200 microsec for a gamma detection). The hard X-ray imager (SuperAGILE) combines a tungsten coded mask with Si detector with a technology identical to the Si-Tracker. It is on top of the gamma-ray detector and has an optimal angular resolution (about 6 arcmin) with good sensitivity over about 1 sr field of view (10–15 mCrab on axis for a 1-day integration). The burst monitoring combines the data from SuperAGILE and from MCAL which operates independently with a specific operative mode from 300 keV up to several tens of MeV. All the detector operations are mastered by the Payload Data Handling Unit (PDHU) that includes several operation for data selection and background rejection. AGILE has very innovative scientific payload for what concern both its detectors and its operative mode. After more than one year of in orbit operation the in-flight performances of the instruments as well as the operation of the background reducing algorithm are presented and the main scientifi-
-
c results achieved are discussed.
Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE; 11/2008
-
S. Mereghetti,
A De Luca,
M Fiorini,
N. La Palombara,
A. Tiengo,
M. Uslenghi,
G. Vianello,
G Villa,
A. Zambra,
A. Moretti, [......],
G. Ghisellini,
G. Pareschi,
G. Tagliaferri,
M. Trifoglio,
L. Amati,
F Gianotti,
L. Stella, A Antonelli,
B. Cordier,
D. Gotz
[show abstract]
[hide abstract]
ABSTRACT: The study of Gamma-ray bursts (GRBs) is a key field to expand our understanding of several astrophysical and cosmological phenomena. SVOM is a Chinese-French Mission which will permit to detect and rapidly locate GRBs, in particular those at high redshift, and to study their multiwavelength emission. The SVOM satellite, to be launched in 2013, will carry wide field instruments operating in the X/gamma-ray band and narrow field optical and soft X-ray telescopes. Here we describe a small soft X-ray telescope (XIAO) proposed as an Italian contribution to the SVOM mission. Thanks to a grazing incidence X-ray telescope with effective area of ~120 cm^2 and a short focal length, coupled to a very compact, low noise, fast read out CCD camera, XIAO can substantially contribute to the overall SVOM capabilities for both GRB and non-GRB science. Comment: 12 pages, 7 figures; Presented at ``SPIE Astronomical Telescopes and Instrumentation 2008'' - Marseille, June 23-28, 2008
07/2008;
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M Alvarez,
D. D'Armiento,
G. Agnetta,
A. Alberdi, A Antonelli,
A. Argan,
P. Assis,
E. A. Baltz,
C. Bambi,
G. Barbiellini, [......],
P. Vallania,
E Vallazza,
S. Vercellone,
S Vernetto,
V Vitale,
N. Wild,
Z. P. Ye,
A. Zambra,
F. Zandanel,
D. Zanello
[show abstract]
[hide abstract]
ABSTRACT: This Conference is the fifth of a series of Workshops on High Energy Gamma- ray Experiments, following the Conferences held in Perugia 2003, Bari 2004, Cividale del Friuli 2005, Elba Island 2006. This year the focus was on the use of gamma-ray to study the Dark Matter component of the Universe, the origin and propagation of Cosmic Rays, Extra Large Spatial Dimensions and Tests of Lorentz Invariance.
01/2008;
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M. Tavani,
G. Barbiellini,
A. Argan,
A. Bulgarelli,
P. Caraveo,
A. Chen,
V. Cocco,
E. Costa,
G. De Paris,
E. Del Monte, [......],
P. Soffitta,
M. Trifoglio,
A. Trois,
E. Vallazza,
S. Vercellone,
A. Zambra,
D. Zanello,
P. Giommi, A. Antonelli,
C. Pittori
[show abstract]
[hide abstract]
ABSTRACT: AGILE is an Italian Space Agency mission dedicated to the exploration of the gamma-ray Universe. The AGILE, very innovative instrument, combines for the first time a gamma-ray imager (sensitive in the range 30 MeV–50 GeV) and a hard X-ray imager (sensitive in the range 18–60 keV). An optimal angular resolution and very large fields of view are obtained by the use of state-of-the-art Silicon detectors integrated in a very compact instrument. AGILE was successfully launched on April 23, 2007 from the Indian base of Sriharikota and was inserted in an optimal low-particle background equatorial orbit. AGILE will provide crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, unidentified gamma-ray sources, galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. The AGILE Cycle-1 pointing program started on 2007 December 1, and is open to the international community through a Guest Observer Program.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2008;
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08/2006;
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Luciano Nicastro,
G. Cusumano, A. Antonelli,
L. Amati,
F. Frontera,
E. Palazzi,
E. Pian,
E. Costa,
M. Feroci,
L. Piro,
J. in’t Zand,
J. Heise
[show abstract]
[hide abstract]
ABSTRACT: GRB000615 was detected simultaneously by the BeppoSAX GRBM and WFC 1 with a localization uncertainty of
2¢2^\prime
(error circle radius). X-ray emission was detected only in the 0.1-4 keV range during a NFI observation started
@ 10\simeq 10
hours after the trigger time. The positional and temporal analysis shows the presence of two sources, one of which may be
related to the GRB.
02/2006: pages 198-200;
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[show abstract]
[hide abstract]
ABSTRACT: on behalf of E. Molinari, G. Chincarini, F.M. Zerbi, S. Covino, G.
Tosti, P. Conconi, G. Cutispoto, L. Nicastro, E. Palazzi, F. Vitali, F.
D'Alessio, E. Meurs, P. Goldoni and the REMIR/ROSS collaboration
We report on infrared observations of the newly discovered transient
X-ray pulsar SWIFT J1626.6-5156 (Palmer et al., ATEL #678, Markwardt
& Swank, ATEL #679 and Campana et al., ATEL #688).
The Astronomer's Telegram. 12/2005; 713:1.
