1,722,994 research outputs found
AGILE observation of gamma-ray variability of the bright blazar 3C 273 during the MWL campaign of Dec 2007 - Jan 2008
No full textEight years after the last EGRET observations in gamma-ray, the GRID (30 MeV - 50 GeV) and SuperAGILE (18 - 60 keV) experiments on board the AGILE mission observed the Virgo sky from December 16, 2007 and January 6, 2008. We organized a multi-wavelength campaign for the FSRQ 3C 273 with joint observations from the REM observatory (covering the near-IR and optical), Swift (near-UV and 0.2-10 keV). We report the preliminary results from the campaign. The first week the source was not detectable in Gamma Rays. Then we detected gamma-ray activity, with a flux comparable to the EGRET detection in June 1991. The hard x light curve show a decrease in flux of ∼ 20% during the period of activity in Gamma-ray. İ Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Divergenze tra il testo tràdito centonario e quello dell’ipotesto nei "Vergiliocentones" del codice Salmasiano: alcune riflessioni metodologiche
No full textRaccolta e analisi di casi in cui le lezioni centonarie differiscono dalle corrispondenti lezioni virgiliane. Riflessioni metodologiche sull'opportunità di ripristinare le lezioni virgiliane o di mantenere quelle tradite dal Salmasiano
I “Vergiliocentones minores” del codice Salmasiano. Introduzione, edizione critica, traduzione e commento
No full textEdizione critica, traduzione e commento filologico-letterario a sei centoni virgiliani dell'Anthologia Latina
The science of AGILE: Part II
No full textIn this paper (Part II) we discuss the expected scientific performance of the AGILE mission, focusing on the large FOV, the spatial resolution and PSF of the gamma-ray imager, and the crucial capability of simultaneous hard-X and gamma-ray imaging with ~1-3 arcmin resolution
Discovery of New Gamma-Ray Pulsars with Agile
No full textUsing gamma-ray data collected by the Astro-rivelatore Gamma ad Immagini LEggero (AGILE) satellite over a period of almost one year (from 2007 July to 2008 June), we searched for pulsed signals from 35 potentially interesting radio pulsars, ordered according to and for which contemporary or recent radio data were available. AGILE detected three new top-ranking nearby and Vela-like pulsars with good confidence both through timing and spatial analysis. Among the newcomers we find pulsars with very high rotational energy losses, such as the remarkable PSRB1509 - 58 with a magnetic field in excess of 1013 Gauss, and PSRJ2229 + 6114 providing a reliable identification for the previously unidentified EGRET source 3EG2227 + 6122. Moreover, the powerful millisecond pulsar B1821 - 24, in the globular cluster M28, is detected during a fraction of the observations. Four other promising gamma-ray pulsar candidates, among which is the notable J2043 + 2740 with an age in excess of 1 million years, show a possible detection in the timing analysis only and deserve confirmation
Il centone virgiliano (AL 7 Riese2): una proposta interpretativa
No full textSi propone una nuova lettura, secondo cui il componimento non descriverebbe la preparazione di pane, bensì di "globi", prodotto dolciario fritto
L’influsso dello "Ione" di Euripide su "The Confidential Clerk" di T.S. Eliot
No full textRicezione dei classici nella teoria letteraria di T.S. Eliot, con particolare riferimento alla fortuna dello "Ione" di Euripide in "The Confidential Clerk"
Search of GRB with AGILE Minicalorimeter
No full textAGILE, the small scientific mission of the Italian Space Agency devoted to Hard-X and Gamma-ray astrophysics, was successfully launched on April 23, 2007. The AGILE payload is composed of a tungsten-silicon tracker (ST), operating in the gamma-ray energy range 30 MeV-50 GeV; Super-AGILE, an X-ray imager operating in the energy range 15-45 keV; the Minicalorimeter (MCAL) and an Anticoincidence shield. MCAL is a detector of about 1400 cm2 sensitive in the range 0.3-200 MeV, that can be used both as a slave of the ST to contribute to the AGILE Gamma Ray imaging Detector (GRID operative mode) and autonomously for detection of transient events (BURST operative mode). MCAL is made of 30 CsI(Tl) bar-shaped scintillation detectors with photodiode readout at both ends, arranged in two orthogonal layers. Energy and position of interaction can be derived from a proper composition of the signals readout at the bar's ends, absolute time tagging can be achieved with a micro s resolution. The Burst logic deals with various rate-meters on different time scales, energy bands, and MCAL spatial zones. Different algorithms can be chosen for Burst triggering considering also the contribution of other detectors like Super AGILE. In this paper the various trigger logic will be reviewed as well as their on-ground test performed with a dedicated experimental setup
The science of AGILE: Part I
No full textAGILE is an ASI Small Scientific Mission dedicated to gamma-ray astrophysics, which will detect and image photons in the 30 MeV - 50 GeV and in the 10-40 keV energy ranges. It is planned to be operational in early 2004 and it will be the only Mission entirely dedicated to source detection above 30 MeV during the period 2004-2006. AGILE will be an excellent gamma-ray imager with a spatial resolution of ~40 μm and a very large FOV (~1/5 of the sky). It allows simultaneous observations in the hard X-ray and in the gamma-ray bands and it is characterized by an optimal temporal resolution (absolute timing of ~2 μs and deadtimes of ~100 μs for the GRID and of ~5 μs for Super-AGILE and the Mini-Calorimeter). AGILE main scientific objectives will be: Active Galactic Nuclei, Gamma-Ray Bursts, Pulsars, unidentified gamma-ray sources and diffuse Galactic and extragalactic gamma-ray emission. In this paper (Part I) we focus on the AGILE scientific goals, the AGILE instrument and the on-board data processin
High-Resolution Timing Observations of Spin-Powered Pulsars with the Agile Gamma-Ray Telescope
No full textAstro-rivelatore Gamma ad Immagini LEggero (AGILE) is a small gamma-ray astronomy satellite mission of the Italian Space Agency dedicated to high-energy astrophysics launched in 2007 April. Its similar to 1 mu s absolute time tagging capability coupled with a good sensitivity in the 30MeV-30 GeV range, with simultaneous X-ray monitoring in the 18-60 keV band, makes it perfectly suited for the study of gamma-ray pulsars following up on the Compton Gamma RayObservatory/EGRET heritage. In this paper, we present the first AGILE timing results on the known gamma-ray pulsars Vela, Crab, Geminga, and B1706-44. The data were collected from 2007 July to 2008 April, exploiting the mission Science Verification Phase, the Instrument Timing Calibration, and the early Observing Pointing Program. Thanks to its large field of view, AGILE collected a large number of gamma-ray photons from these pulsars (similar to 10,000 pulsed counts for Vela) in only few months of observations. The coupling of AGILE timing capabilities, simultaneous radio/X-ray monitoring, and new tools aimed at precise photon phasing, also exploiting timing noise correction, unveiled new interesting features at the submillisecond level in the pulsars' high-energy light curves
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