L. Costamante
A5042040359- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
- Particle Detector Development and Performance
- Pulsars and Gravitational Waves Research
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Particle physics theoretical and experimental studies
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Radiation Detection and Scintillator Technologies
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Computational Physics and Python Applications
- Medical Imaging Techniques and Applications
- Advanced Measurement and Metrology Techniques
- Geomagnetism and Paleomagnetism Studies
Agenzia Spaziale Italiana
2019-2024
Brera Astronomical Observatory
1999-2018
University of Perugia
2013-2018
National Institute for Astrophysics
2016-2017
University of Amsterdam
2016
University of Geneva
2016
Kavli Institute for Particle Astrophysics and Cosmology
2008-2015
Stanford University
2008-2015
SLAC National Accelerator Laboratory
2009-2015
Max Planck Institute for Nuclear Physics
2002-2011
(Abridged) The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on Fermi Gamma-ray Space (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering energy range from below 20 MeV to more than 300 GeV. This paper describes LAT, its pre-flight expected performance, and summarizes key science objectives that will be addressed. On-orbit performance presented in detail a subsequent paper. LAT pair-conversion telescope with precision...
(Abridged) We have conducted a detailed investigation of the broad-band spectral properties \gamma-ray selected blazars Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated gamma-ray spectra with Swift, radio, infra-red, optical and other hard X-ray/gamma-ray data, collected within three months LBAS data taking period, we were able to assemble high-quality quasi-simultaneous Spectral Energy Distributions (SED) for 48 blazars.The SED these sources is similar that...
The Crab nebula was observed with the H.E.S.S. stereoscopic Cherenkov-telescope array between October 2003 and January 2005 for a total of 22.9 hours (after data quality selection). Observations were made three operational telescopes in late complete 4 telescope - February 2004 2005. observations are discussed used as an example to detail flux spectral analysis procedures H.E.S.S., evaluate systematic uncertainties measurements. spectrum gamma-rays from source calculated on run-by-run...
The high-frequency peaked BL Lac PKS 2155-304 at redshift z = 0.116 is a well-known VHE (>100 GeV) γ-ray emitter. Since 2002 its flux has been monitored using the H.E.S.S. stereoscopic array of imaging atmospheric Cerenkov telescopes in Namibia. During 2006 July dark period, average was measured to be more than 10 times typical values observed from object. This article focuses solely on an extreme outburst detected early hours 28 (MJD 53,944). during this I(>200 (1.72 ± 0.05stat 0.34syst) ×...
The very large collection area of ground-based gamma-ray telescopes gives them a substantial advantage over balloon or satellite based instruments in the detection very-high-energy (>600 GeV) cosmic-ray electrons. Here we present electron spectrum derived from data taken with High Energy Stereoscopic System (H.E.S.S.) imaging atmospheric Cherenkov telescopes. In this measurement, first type, are able to extend measurement beyond range accessible direct measurements. We find evidence for...
The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years scientific operation is presented. LAT AGN (2LAC) includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are with a test statistic (TS) greater than 25 and associated statistically AGNs. However, some these affected analysis issues multiple Consequently, we define Clean Sample which 886 AGNs, comprising 395 BL Lacertae objects (BL Lac objects), 310...
Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Burst Monitor and Large Area Telescope onboard Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades gammaray energy. In September 2008, observed exceptionally luminous GRB 080916C, with largest apparent release yet measured. high-energy gamma rays to start later persist longer than lower photons. A simple spectral form fits entire...
We report on a survey of the inner part Galactic Plane in very high energy gamma-rays, with H.E.S.S. Cherenkov telescope system. The between +-30deg longitude and +-3deg latitude relative to Centre was observed 500 pointings for total 230 hours, reaching an average flux sensitivity 2% Crab Nebula at energies above 200 GeV. Fourteen previously unknown sources were detected significance level greater than 4 sigma after accounting all trials involved search. Initial results eight most...
We present the first catalog of active galactic nuclei (AGNs) detected by Large Area Telescope (LAT), corresponding to 11 months data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 γ-ray sources located at high Galactic latitudes (|b|>10°) that are with a test statistic greater than 25 and associated statistically AGNs. Some multiple AGNs, consequently, 709 comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs other types, 72...
ABSTRACT Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope ( ) began a sky survey August. The Large Area (LAT) on three months produced deeper and better resolved map of γ-ray than any previous space mission. We present here initial results for energies above 100 MeV 205 most significant (statistical significance greater ∼10σ) sources these data. These are best characterized localized point-like (i.e., spatially unresolved) early mission
We report the detection of a point-like source very high energy (VHE) gamma-rays coincident within 1' Sgr A*, obtained with H.E.S.S. array Cherenkov telescopes. The exhibit power-law spectrum spectral index -2.2 +/- 0.09 0.15 and flux above 165 GeV threshold (1.82 0.22) * 10^-7 m^-2 s^-1. measured differ substantially from recent results reported in particular by CANGAROO collaboration.
The first three months of sky-survey operation with the Fermi Gamma Ray Space Telescope (Fermi) Large Area (LAT) reveals 132 bright sources at |b|>10 deg test statistic greater than 100 (corresponding to about 10 sigma). Two methods, based on CGRaBS, CRATES and BZCat catalogs, indicate high-confidence associations 106 these known AGNs. This sample is referred as LAT Bright AGN Sample (LBAS). It contains two radio galaxies, namely Centaurus A NGC 1275, 104 blazars consisting 57 flat...
A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by Large Area Telescope on board Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 lasted approximately 16 days. second was September 2010 4 During these outbursts, flux nebula increased factors of four six, respectively. brevity implies that gamma rays were emitted via...
This paper presents light curves as well the first systematic characterization of variability 106 objects in high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly this sample, obtained during 11 months survey (2008 August 4–2009 July 4), are tested for and their properties quantified through autocorrelation function structure analysis. For brightest sources, 3 or 4 day binned extracted order to determine power density spectra (PDSs) fit temporal major flares. More than...
We revisit the blazar sequence exploiting complete, flux-limited sample of blazars with known redshift detected by Fermi satellite after 4 yr operations (the 3LAC sample). divide sources into γ-ray luminosity bins, collect all archival data for blazars, and construct their spectral energy distribution (SED). describe average SED in same bin through a simple phenomenological function consisting two broken power laws connecting law describing radio emission. do that separately BL Lacs flat...
Fermi has provided the largest sample of γ-ray-selected blazars to date. In this work we use a complete flat spectrum radio quasars (FSRQs) detected during first year operation determine luminosity function (LF) and its evolution with cosmic time. The number density FSRQs grows dramatically up redshift ∼0.5–2.0 declines thereafter. peak in is dependent, more luminous sources peaking at earlier times; thus LF γ-ray follows luminosity-dependent similar that radio-quiet active galactic nuclei....
We report the discovery of very-high-energy (VHE) γ-ray emission binary system PSR B1259-63/SS 2883 a radio pulsar orbiting massive, luminous Be star in highly eccentric orbit.The observations around 2004 periastron passage were performed with four 13 m Cherenkov telescopes HESS experiment, recently installed Namibia and full operation since December 2003.Between February June 2004, signal from was detected total significance above 13σ.The flux found to vary significantly on timescales days...
The detection of fast variations the tera-electron volt (TeV) (10(12) eV) gamma-ray flux, on time scales days, from nearby radio galaxy M87 is reported. These are about 10 times as those observed in any other wave band and imply a very compact emission region with dimension similar to Schwarzschild radius central black hole. We thus can exclude several sites processes production. observations confirm that TeV gamma rays emitted by extragalactic sources than blazars, where jets not...
We present deep H.E.S.S. observations of the supernova remnant (SNR) RX J1713.7-3946. Combining data three years - from 2003 to 2005 we obtain significantly increased statistics and energy coverage as compared earlier & 2004 results. The are analysed separately for different years. Very good agreement gamma-ray morphology differential spectra is found when comparing combined image reveals J1713.7-3946 with unprecedented precision. An angular resolution 0.06 deg achieved, revealing...
We present results from deep observations of the Galactic shell-type supernova remnant (SNR) RX J1713.7-3946 (also known as G347.3-0.5) conducted with complete H.E.S.S. array in 2004. Detailed morphological and spatially resolved spectral studies reveal very-high-energy (VHE -- Energies E > 100 GeV) gamma-ray aspects this object unprecedented precision. Since is first in-depth analysis an extended VHE source, we a thorough discussion our methodology investigations possible sources...