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1. Calibration of AGILE-GRID with in-flight data and Monte Carlo simulations

Author

F. Perotti, Ennio Morelli, Massimiliano Fiorini, Sandro Mereghetti, G. Valentini, P. W. Cattaneo, E. Moretti, C. Pittori, A. Rappoldi, V. Vittorini, P. Santolamazza, T. Contessi, G. De Paris, E. Vallazza, Francesco Longo, Fulvio Gianotti, I. Donnarumma, M. Trifoglio, A. Pellizzoni, M. Galli, Piergiorgio Picozza, M. Giusti, Alda Rubini, G. Piano, Paolo Giommi, A. Morselli, Y. Evangelista, F. Verrecchia, G. Di Cocco, Francesco Lazzarotto, E. Striani, Attilio Ferrari, Valentina Fioretti, Marco Tavani, S. Sabatini, Paolo Lipari, A. Argan, Maura Pilia, I. Lapshov, F. Lucarelli, Sergio Colafrancesco, Guido Barbiellini, E. Del Monte, Martino Marisaldi, G. Pucella, Massimo Rapisarda, Alessio Trois, F. Fuschino, Andrea Bulgarelli, M. Prest, D. Zanello, Enrico Costa, C. Labanti, A. Giuliani, P. A. Caraveo, A. W. Chen, S. Vercellone, Marco Feroci, Luigi Pacciani, Paolo Soffitta, Rapisarda, M., Pucella, G., Tadayuki Takahashi, Stephen S. Murray, Jan-Willem A. den Herder, A. W., Chen, A., Argan, A., Bulgarelli, P. W., Cattaneo, A., Giuliani, C., Pittori, G., Pucella, M., Tavani, A., Troi, G., Barbiellini, P., Caraveo, S., Colafrancesco, E., Costa, Paris, G., Monte, E., Cocco, G., I., Donnarumma, Y., Evangelista, A., Ferrari, M., Feroci, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, P., Giommi, M., Giusti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, F., Lucarelli, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Santolamazza, P., Soffitta, E., Striani, M., Trifoglio, L., Salotti, E., Vallazza, S., Vercellone, F., Verrecchia, V., Vittorini, D., Zanello, T., Contessi, BARBIELLINI AMIDEI, Guido, G., De Pari, E., Del Monte, G., Di Cocco, V., Fioretti, Moretti, Elena, and G., Valentini

Subjects
Photon, Monte Carlo method, X-ray telescope, techniques: image processing, Astrophysics, telescope, Orbital mechanics, Vela, High Energy Gamma-ray Astronomy, law.invention, law, imaging detector, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Instrumentation: detector, image processing [techniques], detector [instrumentation], Detector, agile, Astrophysics::Instrumentation and Methods for Astrophysics, Calibrations, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Interpolation, Point spread function, gamma ray source, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Telescope, Optics, data analysis [methods], Calibration, instrumentation: detectors, gamma rays: general, telescopes, methods: data analysis, Instrumentation and Methods for Astrophysics (astro-ph.IM), business.industry, Astronomy and Astrophysics, Kalman filter, calibration, silicon tracker, Computational physics, Space and Planetary Science, Gamma rays: general, Instrumentation: detectors, Methods: data analysis, Techniques: image processing, Telescopes, Orbit (dynamics), AGILE satellite, business, general [gamma rays], Methods: data analysi
Abstract

Context: AGILE is a gamma-ray astrophysics mission which has been in orbit since 23 April 2007 and continues to operate reliably. The gamma-ray detector, AGILE-GRID, has observed Galactic and extragalactic sources, many of which were collected in the first AGILE Catalog. Aims: We present the calibration of the AGILE-GRID using in-flight data and Monte Carlo simulations, producing Instrument Response Functions (IRFs) for the effective area A_eff), Energy Dispersion Probability (EDP), and Point Spread Function (PSF), each as a function of incident direction in instrument coordinates and energy. Methods: We performed Monte Carlo simulations at different gamma-ray energies and incident angles, including background rejection filters and Kalman filter-based gamma-ray reconstruction. Long integrations of in-flight observations of the Vela, Crab and Geminga sources in broad and narrow energy bands were used to validate and improve the accuracy of the instrument response functions. Results: The weighted average PSFs as a function of spectra correspond well to the data for all sources and energy bands. Conclusions: Changes in the interpolation of the PSF from Monte Carlo data and in the procedure for construction of the energy-weighted effective areas have improved the correspondence between predicted and observed fluxes and spectra of celestial calibration sources, reducing false positives and obviating the need for post-hoc energy-dependent scaling factors. The new IRFs have been publicly available from the Agile Science Data Centre since November 25, 2011, while the changes in the analysis software will be distributed in an upcoming release.

Published
2013

2. AGILE detection of Cygnus X-3 {\gamma}-ray active states during the period mid-2009/mid-2010

Author

E. Moretti, Maura Pilia, Guy G. Pooley, V. Vittorini, G. De Paris, G. Di Cocco, M. Trifoglio, Alessio Trois, A. Rappoldi, E. Vallazza, L. Salotti, F. Perotti, Francesco Lazzarotto, Francesco Longo, C. Pittori, A. Zambra, Paolo Soffitta, A. Morselli, A. Giuliani, Danny Steeghs, A. Pellizzoni, Y. Evangelista, I. Donnarumma, V. Cocco, Marco Tavani, D. Zanello, T. Contessi, M. Galli, Piergiorgio Picozza, S. Vercellone, E. Striani, Fulvio Gianotti, G. Piano, Michael L. McCollough, S. Sabatini, Sergio Colafrancesco, F. Verrecchia, P. Santolamazza, I. Lapshov, Alda Rubini, N. A. Nizhelskij, E. Del Monte, Sandro Mereghetti, Paolo Giommi, P. W. Cattaneo, N. Lavonen, A. W. Chen, Anne Lähteenmäki, Alessio Aboudan, Massimo Rapisarda, S. A. Trushkin, Guido Barbiellini, Joni Tammi, M. Prest, D. Hannikainen, Marco Feroci, Luigi Pacciani, C. Labanti, Filippo D'Ammando, A. Argan, Andrea Bulgarelli, Martino Marisaldi, Enrico Costa, M. Giusti, Karri I. I. Koljonen, Ennio Morelli, Massimiliano Fiorini, P. A. Caraveo, G. Pucella, Paolo Lipari, F. Lucarelli, F. Fuschino, Riccardo Campana, A., Bulgarelli, M., Tavani, A. W., Chen, Y., Evangelista, M., Trifoglio, F., Gianotti, G., Piano, S., Sabatini, E., Striani, G., Pooley, S., Trushkin, N. A., Nizhelskij, M., Mccollough, K. I., I., D., Hannikainen, A., L\ahteenm\aki, J., Tammi, N., Lavonen, D., Steegh, A., Aboudan, A., Argan, G., Barbiellini, R., Campana, P., Caraveo, P. W., Cattaneo, V., Cocco, T., Contessi, E., Costa, F., D'Ammando, Monte, E., Paris, G., Cocco, G., I., Donnarumma, M., Feroci, M., Fiorini, F., Fuschino, M., Galli, A., Giuliani, M., Giusti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, A., Rubini, P., Soffitta, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, P., Giommi, C., Pittori, F., Verrecchia, P., Santolamazza, F., Lucarelli, S., Colafrancesco, L., Salotti, Bulgarelli A, Tavani M, Chen AW, Evangelista Y, Trifoglio M, Gianotti F, Piano G, Sabatini S, Striani E, Pooley G, Trushkin S, Nizhelskij NA, McCollough M, Koljonen KII, Hannikainen D, Lahteenmaki A, Tammi J, Lavonen N, Steeghs D, Aboudan A, Argan A, Barbiellini G, Campana R, Caraveo P, Cattaneo PW, Cocco V, Contessi T, Costa E, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Donnarumma I, Feroci M, Fiorini M, Fuschino F, Galli M, Giuliani A, Giusti M, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mereghetti S, Morelli E, Moretti E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Pilia M, Prest M, Pucella G, Rapisarda M, Rappoldi A, Rubini A, Soffitta P, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Giommi P, Pittori C, Verrecchia F, Santolamazza P, Lucarelli F, Colafrancesco S, Salotti L, Anne Lähteenmäki Group, Aalto-yliopisto, and Aalto University

Subjects
gamma-rays: stars, education, Flux, Astrophysics, 01 natural sciences, gamma-rays: stars – stars: individual: Cygnus X-3, stars [gamma-rays], Acceleration, Astrophysical jet, 0103 physical sciences, MAGIC (telescope), microquasar, Cygnus X-3, 010303 astronomy & astrophysics, QB, stars: individual: Cygnus X-3, Physics, star [gamma-rays], 010308 nuclear & particles physics, AGILE satellite, gamma rays, Gamma ray, Astronomy and Astrophysics, Particle acceleration, Wavelength, Space and Planetary Science, individual: Cygnus X-3 [stars], Production (computer science), Astrophysics - High Energy Astrophysical Phenomena
Abstract

Cygnus X-3 (Cyg X-3) is a well-known microquasar producing variable emission at all wavelengths. Cyg X-3 is a prominent X-ray binary producing relativistic jets, and studying its high energy emission is crucial for the understanding of the fundamental acceleration processes in accreting compact objects. Aims. Our goal is to study extreme particle acceleration and {\gamma}-ray production above 100 MeV during special spectral states of Cyg X- 3 usually characterized by a low hard X-ray flux and enhanced soft X-ray states. We observed Cyg X-3 with the AGILE satellite in extended time intervals from 2009 Jun.-Jul., and 2009 Nov.-2010 Jul. We report here the results of the AGILE {\gamma}-ray monitoring of Cyg X-3 as well as the results from extensive multiwavelength campaigns involving radio (RATAN-600, AMI-LA and Mets\"{a}hovi Radio Observatories) and X-ray monitoring data (XTE and Swift). We detect a series of repeated {\gamma}-ray flaring activity from Cyg X-3 that correlate with the soft X-ray states and episodes of decreasing or non-detectable hard X-ray emission. Furthermore, we detect {\gamma}-ray enhanced emission that tends to be associated with radio flares greater than 1 Jy at 15 GHz, confirming a trend already detected in previous observations. The source remained active above 100 MeV for an extended period of time (almost 1.5 months in 2009 Jun.-Jul. and 1 month in 2010 May). We study in detail the short timescale {\gamma}-ray flares that occurred before or near the radio peaks. Our results confirm the transient nature of the extreme particle acceleration from the microquasar Cyg X-3. A series of repeated {\gamma}-ray flares shows correlations with radio and X-ray emission confirming a well established trend of emission. We compare our results with Fermi-LAT and MAGIC TeV observations of Cyg X-3., Comment: 16 pages, 8 figures, 7 tables; A&A (2011)

Published
2011

3. Neutral Pion Emission from Accelerated Protons in the Supernova Remnant W44

Author

Yasuo Fukui, E. Striani, Y. Evangelista, E. Del Monte, C. Pittori, Guido Barbiellini, F. Lucarelli, A. Pellizzoni, Kazufumi Torii, Paolo Soffitta, Giovanni F. Bignami, M. Cardillo, Massimo Rapisarda, Satoshi Yoshiike, Gloria Mabel Dubner, Francesco Longo, G. Castelletti, I. Donnarumma, Andrea Bulgarelli, Enrico Costa, S. Vercellone, G. Pucella, P. Picozza, A. Rappoldi, A. Giuliani, V. Vittorini, Paolo Giommi, M. Trifoglio, A. W. Chen, Marco Feroci, Luigi Pacciani, P. A. Caraveo, Francesco Lazzarotto, Alessio Trois, F. Verrecchia, Fulvio Gianotti, Martino Marisaldi, Marco Tavani, S. Sabatini, Sergio Colafrancesco, Sandro Mereghetti, T. Contessi, P. W. Cattaneo, G. Piano, A., Giuliani, M., Cardillo, M., Tavani, Y., Fukui, S., Yoshiike, K., Torii, G., Dubner, G., Castelletti, G., Barbiellini, A., Bulgarelli, P., Caraveo, E., Costa, P. W., Cattaneo, A., Chen, T., Contessi, Monte, E., I., Donnarumma, Y., Evangelista, M., Feroci, F., Gianotti, F., Lazzarotto, F., Lucarelli, Longo, Francesco, M., Marisaldi, S., Mereghetti, L., Pacciani, A., Pellizzoni, G., Piano, P., Picozza, C., Pittori, G., Pucella, M., Rapisarda, A., Rappoldi, S., Sabatini, P., Soffitta, E., Striani, M., Trifoglio, A., Troi, S., Vercellone, F., Verrecchia, V., Vittorini, S., Colafrancesco, P., Giommi, and G., Bignami

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Hadron, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Radiation, Spectral line, Pion, acceleration of particles, cosmic rays, gamma rays: general, ISM: supernova remnants, Ejecta, Supernova remnant, acceleration of particle, cosmic ray, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Range (particle radiation), Molecular cloud, supernova remnants [ISM], Astronomy and Astrophysics, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, general [gamma rays]
Abstract

We present the AGILE gamma-ray observations in the energy range 50 MeV - 10 GeV of the supernova remnant (SNR) W44, one of the most interesting systems for studying cosmic-ray production. W44 is an intermediate-age SNR (20, 000 years) and its ejecta expand in a dense medium as shown by a prominent radio shell, nearby molecular clouds, and bright [SII] emitting regions. We extend our gamma-ray analysis to energies substantially lower than previous measurements which could not conclusively establish the nature of the radiation. We find that gamma-ray emission matches remarkably well both the position and shape of the inner SNR shocked plasma. Furthermore, the gamma-ray spectrum shows a prominent peak near 1 GeV with a clear decrement at energies below a few hundreds of MeV as expected from neutral pion decay. Here we demonstrate that: (1) hadron-dominated models are consistent with all W44 multiwavelength constraints derived from radio, optical, X-ray, and gamma-ray observations; (2) ad hoc lepton-dominated models fail to explain simultaneously the well-constrained gamma-ray and radio spectra, and require a circumstellar density much larger than the value derived from observations; (3) the hadron energy spectrum is well described by a power-law (with index s = 3.0 \pm 0.1) and a low-energy cut-off at Ec = 6 \pm 1 GeV. Direct evidence for pion emission is then established in an SNR for the first time., accepted for publication on ApJL

Published
2011

4. Direct Evidence for Hadronic Cosmic-Ray Acceleration in the Supernova Renmant IC 443

Author

C. Pittori, Marco Feroci, F. Fuschino, Luigi Pacciani, Paolo Soffitta, G. De Paris, A. Giuliani, E. Scalise, Filippo D'Ammando, V. Cocco, M. Mastropietro, E. Del Monte, V. Vittorini, Arnaud Ferrari, Paolo Lipari, M. Trifoglio, Y. Evangelista, S. Vercellone, F. Perotti, Francesco Lazzarotto, P. Santolamazza, A. Zambra, A. Pellizzoni, G. Di Cocco, E. Striani, I. Lapshov, Fulvio Gianotti, I. Donnarumma, Martino Marisaldi, L. Salotti, Elena Moretti, Alda Rubini, P. W. Cattaneo, A. Rappoldi, A. W. Chen, P. Picozza, P. Giommi, Massimo Rapisarda, G. Pucella, F. Longo, D. Zanello, A. Argan, Andrea Bulgarelli, T. Contessi, Enrico Costa, Claudio Labanti, L. A. Antonelli, G. Piano, P. A. Caraveo, M. Galli, F. Verrecchia, Sandro Mereghetti, A. Morselli, S. Colafrancesco, M. Prest, Alessio Trois, M. Pilia, Marco Tavani, S. Sabatini, Ennio Morelli, G. Barbiellini, E. Vallazza, M., Tavani, A., Giuliani, A. W., Chen, A., Argan, G., Barbiellini, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, V., Cocco, T., Contessi, F., D'Ammando, E., Costa, G. D., Pari, E. D., Monte, G. D., Cocco, I., Donnarumma, Y., Evangelista, A., Ferrari, M., Feroci, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, M., Mastropietro, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, G., Pucella, M., Prest, M., Rapisarda, A., Rappoldi, E., Scalise, A., Rubini, S., Sabatini, E., Striani, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, P., Santolamazza, P., Giommi, S., Colafrancesco, L. A., Antonelli, L., Salotti, Tavani M, Giuliani A, Chen AW, Argan A, Barbiellini G, Bulgarelli A, Caraveo P, Cattaneo PW, Cocco V, Contessi T, DAmmando F, Costa E, De Paris G, Del Monte E, Di Cocco G, Donnarumma I, Evangelista Y, Ferrari A, Feroci M, Fuschino F, Galli M, Gianotti F, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mastropietro M, Mereghetti S, Morelli E, Moretti E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Pucella G, Prest M, Rapisarda M, Rappoldi A, Scalise E, Rubini A, Sabatini S, Striani E, Soffitta P, Trifoglio M, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Verrecchia F, Santolamazza P, Giommi P, Colafrancesco S, Antonelli LA, and Salotti L

Subjects
Agile, Photon, Supernova Remnants, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Cosmic ray, Electron, Astrophysics, High Energy Gamma-ray Astronomy, gamma ray production, supernova, Supernova remnant, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Molecular cloud, AGILE satellite, Gamma ray, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Supernova, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena, cosmic rays – gamma rays: general – ISM: supernova remnants – supernovae: general – supernovae: individual (IC 443)
Abstract

The Supernova Remnant (SNR) IC 443 is an intermediate-age remnant well known for its radio, optical, X-ray and gamma-ray energy emissions. In this Letter we study the gamma-ray emission above 100 MeV from IC 443 as obtained by the AGILE satellite. A distinct pattern of diffuse emission in the energy range 100 MeV-3 GeV is detected across the SNR with its prominent maximum (source "A") localized in the Northeastern shell with a flux F = (47 \pm 10) 10^{-8} photons cm^{-2} s^{-1} above 100 MeV. This location is the site of the strongest shock interaction between the SNR blast wave and the dense circumstellar medium. Source "A" is not coincident with the TeV source located 0.4 degree away and associated with a dense molecular cloud complex in the SNR central region. From our observations, and from the lack of detectable diffuse TeV emission from its Northeastern rim, we demonstrate that electrons cannot be the main emitters of gamma-rays in the range 0.1-10 GeV at the site of the strongest SNR shock. The intensity, spectral characteristics, and location of the most prominent gamma-ray emission together with the absence of co-spatial detectable TeV emission are consistent only with a hadronic model of cosmic-ray acceleration in the SNR. A high-density molecular cloud (cloud "E") provides a remarkable "target" for nucleonic interactions of accelerated hadrons: our results show enhanced gamma-ray production near the molecular cloud/shocked shell interaction site. IC 443 provides the first unambiguous evidence of cosmic-ray acceleration by SNRs., Comment: 5 pages, 2 figures; accepted by ApJLetters on Jan 21, 2010

Published
2010
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5. Extreme particle acceleration in the microquasar Cygnus X-3

Author

Francesco Longo, Martino Marisaldi, C. Pittori, Paolo Lipari, Arnaud Ferrari, M. Prest, Sandro Mereghetti, P. W. Cattaneo, S. Sabatini, A. Pellizzoni, E. Striani, I. Lapshov, F. Perotti, S. Colafrancesco, Fulvio Gianotti, Francesco Lazzarotto, A. Giuliani, E. Rossi, Ennio Morelli, Karri I. I. Koljonen, Marco Tavani, E. Scalise, Y. Evangelista, Maura Pilia, Guy G. Pooley, M. Galli, F. Fuschino, Alessio Trois, I. Donnarumma, Massimo Rapisarda, F. Verrecchia, N. A. Nizhelskij, P. A. Caraveo, E. Del Monte, D. Zanello, L. Salotti, V. Cocco, M. Trifoglio, G. Pucella, A. Mauri, A. Rappoldi, E. Vallazza, G. De Paris, T. Contessi, G. Piano, A. W. Chen, P. Giommi, A. Argan, Andrea Bulgarelli, Enrico Costa, G. Di Persio, A. Morselli, Filippo D'Ammando, Paolo Soffitta, S. Vercellone, Michael L. McCollough, P. Picozza, P. Santolamazza, Alda Rubini, Sergei A. Trushkin, A. Zambra, M. Mastropietro, Guido Barbiellini, V. Vittorini, Marco Feroci, Luigi Pacciani, Angelo Antonelli, E. Mattaini, G. Di Cocco, Claudio Labanti, M., Tavani, A., Bulgarelli, G., Piano, S., Sabatini, E., Striani, Y., Evangelista, A., Troi, G., Pooley, S., Trushkin, N. A., Nizhelskij, M., Mccollough, K. I. I., Koljonen, G., Pucella, A., Giuliani, A. W., Chen, E., Costa, V., Vittorini, M., Trifoglio, F., Gianotti, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, V., Cocco, T., Contessi, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, G. D., Persio, I., Donnarumma, M., Feroci, A., Ferrari, F., Fuschino, M., Galli, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, E., Mattaini, M., Marisaldi, M., Mastropietro, A., Mauri, S., Mereghetti, E., Morelli, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, E., Rossi, A., Rubini, E., Scalise, P., Soffitta, E., Vallazza, S., Vercellone, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, P., Giommi, S., Colafrancesco, P., Santolamazza, A., Antonelli, L., Salotti, Tavani M, Bulgarelli A, Piano G, Sabatini S, Striani E, Evangelista Y, Trois A, Pooley G, Trushkin S, Nizhelskij NA, McCollough M, Koljonen KII, Pucella G, Giuliani A, Chen AW, Costa E, Vittorini V, Trifoglio M, Gianotti F, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Cocco V, Contessi T, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Feroci M, Ferrari A, Fuschino F, Galli M, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Mattaini E, Marisaldi M, Mastropietro M, Mauri A, Mereghetti S, Morelli E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Pilia M, Prest M, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Scalise E, Soffitta P, Vallazza E, Vercellone S, Zambra A, Zanello D, Pittori C, Verrecchia F, Giommi P, Colafrancesco S, Santolamazza P, Antonelli A, and Salotti L

Subjects
Active galactic nucleus, Black Holes, Astrophysics::High Energy Astrophysical Phenomena, super massive black holes, X-ray binary, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, High Energy Gamma-ray Astronomy, Relativistic particle, AGILE, Astrophysical jet, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Supermassive black hole, Cygnus, Multidisciplinary, particle acceleration, microquasar, Cygnus X-3, Astronomy, X-ray emission, Particle acceleration, Black hole, Neutron star, AGILE satellite
Abstract

Galactic microquasars are binaries with a neutron star or stellar-mass black hole accreting gas from a companion star. They can accelerate particles to relativistic energies and emit radio flares, but the mechanism of jet energization is not known. A survey of the Cygnus region between mid-2007 and mid-2009 has detected four major γ-ray flaring episodes with energies over 100 MeV, each lasting 1 or 2 days, emanating from the microquasar Cygnus X-3. There is a clear pattern of temporal correlation between the γ-ray flares and transitional spectral states of radio and X-ray emission. Particle acceleration occurred a few days before radio jet ejections for two of the flares, suggesting that jet formation involves the production of highly energetic particles. Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated γ-ray emission. Galactic 'microquasars' also produce relativistic jets; however, 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. Here, a report of four γ-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 illuminates this important problem. Super-massive black holes in active galaxies can accelerate particles to relativistic energies1, producing jets with associated γ-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 flares2. Apart from an isolated event detected3 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 γ-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary4,5,6 that sporadically produces radio jets7,8,9). There is a clear pattern of temporal correlations between the γ-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.

Published
2009

6. First AGILE catalog of high-confidence gamma-ray sources

Author

Dario Gasparrini, I. Donnarumma, F. Mauri, E. Scalise, E. Mattaini, G. Di Cocco, E. Del Monte, E. Rossi, Geiland Porrovecchio, Fulvio Gianotti, F. Fornari, A. Morselli, G. De Paris, Marco Feroci, Luigi Pacciani, G. Di Persio, S. Cutini, A. W. Chen, Sandro Mereghetti, F. Boffelli, P. W. Cattaneo, S. Stellato, Francesco Longo, Massimo Rapisarda, R. Primavera, A. Antonelli, Filippo D'Ammando, M. Galli, Piergiorgio Picozza, F. Tamburelli, C. Pittori, L. Salotti, Paolo Soffitta, F. Verrecchia, A. Zambra, T. Froysland, B. Preger, P. Santolamazza, D. Zanello, V. Vittorini, G. Fanari, F. Fuschino, F. Perotti, Martino Marisaldi, A. Pellizzoni, Marcello Mastropietro, Francesco Lazzarotto, M. Trifoglio, A. Argan, Massimo Frutti, Andrea Bulgarelli, Maura Pilia, P. A. Caraveo, Enrico Costa, Alessio Trois, F. Liello, Claudio Labanti, Alda Rubini, E. Striani, Marco Tavani, S. Vercellone, S. Sabatini, Sergio Colafrancesco, I. Lapshov, Paolo Giommi, Ennio Morelli, M. Prest, Massimiliano Fiorini, P. Lipari, Attilio Ferrari, Guido Barbiellini, Elena Moretti, G. Pucella, A. Mauri, A. Rappoldi, E. Vallazza, Alessandro Traci, V. Cocco, A. Giuliani, Y. Evangelista, T. Contessi, G. Piano, C. Pontoni, C., Pittori, F., Verrecchia, A. W., Chen, A., Bulgarelli, A., Pellizzoni, A., Giuliani, S., Vercellone, Longo, Francesco, M., Tavani, P., Giommi, G., Barbiellini, M., Trifoglio, F., Gianotti, A., Argan, A., Antonelli, F., Boffelli, P., Caraveo, P. W., Cattaneo, V., Cocco, S., Colafrancesco, T., Contessi, E., Costa, S., Cutini, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, G. D., Persio, I., Donnarumma, Y., Evangelista, G., Fanari, M., Feroci, A., Ferrari, M., Fiorini, F., Fornari, F., Fuschino, T., Froysland, M., Frutti, M., Galli, D., Gasparrini, C., Labanti, I., Lapshov, F., Lazzarotto, F., Liello, P., Lipari, E., Mattaini, M., Marisaldi, M., Mastropietro, A., Mauri, F., Mauri, S., Mereghetti, E., Morelli, Moretti, Elena, A., Morselli, L., Pacciani, F., Perotti, G., Piano, P., Picozza, M., Pilia, C., Pontoni, G., Porrovecchio, B., Preger, M., Prest, R., Primavera, G., Pucella, M., Rapisarda, A., Rappoldi, E., Rossi, A., Rubini, S., Sabatini, P., Santolamazza, E., Scalise, P., Soffitta, S., Stellato, E., Striani, F., Tamburelli, A., Traci, A., Troi, E., Vallazza, V., Vittorini, A., Zambra, D., Zanello, L., Salotti, Pittori C, Verrecchia F, Chen AW, Bulgarelli A, Pellizzoni A, Giuliani A, Vercellone S, Longo F, Tavani M, Giommi P, Barbiellini G, Trifoglio M, Gianotti F, Argan A, Antonelli A, Boffelli F, Caraveo P, Cattaneo PW, Cocco V, Colafrancesco S, Contessi T, Costa E, Cutini S, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Evangelista Y, Fanari G, Feroci M, Ferrari A, Fiorini M, Fornari F, Fuschino F, Froysland T, Frutti M, Galli M, Gasparrini D, Labanti C, Lapshov I, Lazzarotto F, Liello F, Lipari P, Mattaini E, Marisaldi M, Mastropietro M, Mauri A, Mauri F, Mereghetti S, Morelli E, Moretti E, Morselli A, Pacciani L, Perotti F, Piano G, Picozza P, Pilia M, Pontoni C, Porrovecchio G, Preger B, Prest M, Primavera R, Pucella G, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Sabatini S, Santolamazza P, Scalise E, Soffitta P, Stellato S, Striani E, Tamburelli F, Traci A, Trois A, Vallazza E, Vittorini V, Zambra A, Zanello D, and Salotti L

Subjects
Agile, catalog, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Field of view, Astrophysics, gamma-ray source, High Energy Gamma-ray Astronomy, Pulsar, X and gamma detection, Blazar, media_common, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Detector, Gamma ray, gamma rays: observations, catalogs, Astronomy and Astrophysics, Radius, AGILE satellite, Catalogs, Space and Planetary Science, Sky, Satellite, Astrophysics - High Energy Astrophysical Phenomena
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., 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)

Published
2009

7. Multiwavelength Observations Of 3c 454.3. Ii. The Agile 2007 December Campaign

Author

I. Donnarumma, G. Pucella, V. Vittorini, F. D'Ammando, S. Vercellone, C. M. Raiteri, M. Villata, M. Perri, W. P. Chen, R. L. Smart, J. Kataoka, N. Kawai, Y. Mori, G. Tosti, D. Impiombato, T. Takahashi, R. Sato, M. Tavani, A. Bulgarelli, A. W. Chen, A. Giuliani, F. Longo, L. Pacciani, A. Argan, G. Barbiellini, F. Boffelli, P. Caraveo, P. W. Cattaneo, V. Cocco, T. Contessi, E. Costa, E. Del Monte, G. De Paris, G. Di Cocco, Y. Evangelista, M. Feroci, A. Ferrari, M. Fiorini, T. Froysland, M. Frutti, F. Fuschino, M. Galli, F. Gianotti, C. Labanti, I. Lapshov, F. Lazzarotto, P. Lipari, M. Marisaldi, M. Mastropietro, S. Mereghetti, E. Morelli, E. Moretti, A. Morselli, A. Pellizzoni, F. Perotti, G. Piano, P. Picozza, M. Pilia, G. Porrovecchio, M. Prest, M. Rapisarda, A. Rappoldi, A. Rubini, S. Sabatini, E. Scalise, P. Soffitta, E. Striani, M. Trifoglio, A. Trois, E. Vallazza, A. Zambra, D. Zanello, C. Pittori, P. Santolamazza, F. Verrecchia, P. Giommi, L. A. Antonelli, S. Colafrancesco, L. Salotti, Donnarumma I, Pucella G, Vittorini V, DAmmando F, Vercellone S, Raiteri CM, Villata M, Perri M, Chen WP, Smart RL, Kataoka J, Kawai N, Mori Y, Tosti G, Impiombato D, Takahashi T, Sato R, Tavani M, Bulgarelli A, Chen AW, Giuliani A, Longo F, Pacciani L, Argan A, Barbiellini G, Boffelli F, Caraveo P, Cattaneo PW, Cocco V, Contessi T, Costa E, Del Monte E, De Paris G, Di Cocco G, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Froysland T, Frutti M, Fuschino F, Galli M, Gianotti F, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Marisaldi M, Mastropietro M, Mereghetti S, Morelli E, Moretti E, Morselli A, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Porrovecchio G, Prest M, Rapisarda M, Rappoldi A, Rubini A, Sabatini S, Scalise E, Soffitta P, Striani E, Trifoglio M, Trois A, Vallazza E, Zambra A, Zanello D, Pittori C, Santolamazza P, Verrecchia F, Giommi P, Antonelli A, Colafrancesco S, Salotti L, I., Donnarumma, G., Pucella, V., Vittorini, F., D'Ammando, S., Vercellone, C. M., Raiteri, M., Villata, M., Perri, W. P., Chen, R. L., Smart, J., Kataoka, N., Kawai, Y., Mori, G., Tosti, D., Impiombato, T., Takahashi, R., Sato, M., Tavani, A., Bulgarelli, A. W., Chen, A., Giuliani, Longo, Francesco, L., Pacciani, A., Argan, G., Barbiellini, F., Boffelli, P., Caraveo, P. W., Cattaneo, V., Cocco, T., Contessi, E., Costa, E. D., Monte, G. D., Pari, G. D., Cocco, Y., Evangelista, M., Feroci, A., Ferrari, M., Fiorini, T., Froysland, M., Frutti, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, M., Marisaldi, M., Mastropietro, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, G., Porrovecchio, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, E., Scalise, P., Soffitta, E., Striani, M., Trifoglio, A., Troi, E., Vallazza, A., Zambra, D., Zanello, C., Pittori, P., Santolamazza, F., Verrecchia, P., Giommi, A., Antonelli, S., Colafrancesco, and L., Salotti

Subjects
Agile, Photon, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, Flux, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, blazar, law.invention, law, Target of opportunity, quasars: general, multiwavelength campaign, Blazar, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), We report on the second Astrorivelatore Gamma a Immagini Leggero (AGILE) multiwavelength campaign of the blazar 3C 454.3 during the first half of 2007 December. This campaign involved AGILE, Spitzer, Swift, Suzaku, the Whole Earth Blazar Telescope (WEBT) consortium, the Rapid Eye Mount (REM), and the Multicolor Imaging Telescopes for Survey and Monstrous Explosions (MITSuME) telescopes, offering a broadband coverage that allowed for a simultaneous sampling of the synchrotron and inverse Compton (IC) emissions. The two-week AGILE monitoring was accompanied by radio to optical monitoring by WEBT and REM, and by sparse observations in mid-infrared and soft/hard X-ray energy bands performed by means of Target of Opportunity observations by Spitzer, Swift, and Suzaku, respectively. The source was detected with an average flux of ~250 × 10^-8 photons cm^-2 s^-1 above 100 MeV, typical of its flaring states. The simultaneous optical and γ-ray monitoring allowed us to study the time lag associated with the variability in the two energy bands, resulting in a possible lsimone-day delay of the γ-ray emission with respect to the optical one. From the simultaneous optical and γ-ray fast flare detected on December 12, we can constrain the delay between the γ-ray and optical emissions within 12 hr. Moreover, we obtain three spectral energy distributions (SEDs) with simultaneous data for 2007 December 5, 13, and 15, characterized by the widest multifrequency coverage. We found that a model with an external Compton on seed photons by a standard disk and reprocessed by the broad-line regions does not describe in a satisfactory way the SEDs of 2007 December 5, 13, and 15. An additional contribution, possibly from the hot corona with T = 106 K surrounding the jet, is required to account simultaneously for the softness of the synchrotron and the hardness of the IC emissions during those epochs, Astronomy and Astrophysics, galaxies: jets, radiation mechanisms: non-thermal, Corona, Synchrotron, Space and Planetary Science, galaxies: individual: 3C 454.3, Astrophysics - High Energy Astrophysical Phenomena, gamma rays: observations, Astrophysics - Cosmology and Nongalactic Astrophysics, Flare
Abstract

著者人数：79名, Accepted: 2009-10-29, 資料番号: SA1000754000

Published
2009

8. Detection of Gamma-Ray Emission from the Vela Pulsar Wind Nebula with AGILE

Author

A. Pellizzoni, M. Galli, A. Giuliani, F. Verrecchia, Francesco Lazzarotto, E. Vallazza, C. Pittori, T. Contessi, N. D'Amico, G. Piano, G. De Paris, A. Argan, Sandro Mereghetti, E. Rossi, E. Scalise, A. Morselli, Arnaud Ferrari, E. Striani, P. Santolamazza, Andrea Bulgarelli, F. Fuschino, I. Lapshov, S. Colafrancesco, L. Salotti, I. Donnarumma, Y. Evangelista, Massimo Rapisarda, G. Di Cocco, A. Possenti, Enrico Costa, S. Sabatini, Alda Rubini, P. W. Cattaneo, G. Pucella, P. Picozza, Marco Tavani, G. Barbiellini, Elena Moretti, Martino Marisaldi, A. Rappoldi, D. Zanello, M. Prest, V. Cocco, M. Mastropietro, F. Perotti, M. Burgay, V. Vittorini, A. W. Chen, Claudio Labanti, A. Zambra, Paolo Lipari, P. Giommi, J. Palfreyman, Giovanni F. Bignami, P. A. Caraveo, M. Trifoglio, M. Fiorini, E. Del Monte, Aidan Hotan, F. Longo, Angelo Antonelli, Marco Feroci, Luigi Pacciani, Maura Pilia, Alessio Trois, Paolo Esposito, Fulvio Gianotti, G. Di Persio, Filippo D'Ammando, Paolo Soffitta, S. Vercellone, Pellizzoni A, Trois A, Tavani M, Pilia M, Giuliani A, Pucella G, Esposito P, Sabatini S, Piano G, Argan A, Barbiellini G, Bulgarelli A, Burgay M, Caraveo P, Cattaneo PW, Chen AW, Cocco V, Contessi T, Costa E, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Fuschino F, Galli M, Gianotti F, Hotan A, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mastropietro M, Mereghetti S, Moretti E, Morselli A, Pacciani L, Palfreyman J, Perotti F, Picozza P, Pittori C, Possenti A, Prest M, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Santolamazza P, Scalise E, Soffitta P, Striani E, Trifoglio M, Vallazza E, Vercellone S, Verrecchia F, Vittorini V, Zambra A, Zanello D, Giommi P, Colafrancesco S, Antonelli A, Salotti L, D'Amico N, Bignami GF, A., Pellizzoni, A., Troi, M., Tavani, M., Pilia, A., Giuliani, G., Pucella, P., Esposito, S., Sabatini, G., Piano, A., Argan, G., Barbiellini, A., Bulgarelli, M., Burgay, P., Caraveo, P. W., Cattaneo, A. W., Chen, V., Cocco, T., Contessi, E., Costa, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, G. D., Persio, I., Donnarumma, Y., Evangelista, M., Feroci, A., Ferrari, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, A., Hotan, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, M., Mastropietro, S., Mereghetti, E., Moretti, A., Morselli, L., Pacciani, J., Palfreyman, F., Perotti, P., Picozza, C., Pittori, A., Possenti, M., Prest, M., Rapisarda, A., Rappoldi, E., Rossi, A., Rubini, P., Santolamazza, E., Scalise, P., Soffitta, E., Striani, M., Trifoglio, E., Vallazza, S., Vercellone, F., Verrecchia, V., Vittorini, A., Zambra, D., Zanello, P., Giommi, S., Colafrancesco, A., Antonelli, L., Salotti, N., D'Amico, and G. F., Bignami

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Vela, Pulsar wind nebula, High Energy Gamma-ray Astronomy, gamma detection, Relativistic particle, AGILE, Pulsar Wind Nebulae, Pulsar, Astrophysics::Solar and Stellar Astrophysics, AGILE satellite, education, Astrophysics::Galaxy Astrophysics, pulsar, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, Multidisciplinary, Vela Pulsar Wind Nebula, AGILE, gamma-rays, Gamma ray, Astronomy, Physics::Space Physics, Astrophysics - High Energy Astrophysical Phenomena, Phenomenology (particle physics), X-ray pulsar
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 (PWNe) are observed in the radio, optical, x-rays and, in some cases, also at TeV energies, but the lack of information in the gamma-ray band prevents from 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, probing multivavelength PWN models, and establishes a class of gamma-ray emitters that could account for a fraction of the unidentified Galactic gamma-ray sources., Comment: Accepted by Science; first published online on December 31, 2009 in Science Express. Science article and Supporting Online Material are available at http://www.sciencemag.org

Published
2009
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9. An updated list of AGILE bright gamma-ray sources and their variability in pointing mode

Author

L. Salotti, A. Trois, E. Mattaini, G. Di Cocco, Francesco Lucarelli, F. Gianotti, G. Barbiellini, R. Primavera, A. Rubini, F. Mauri, M. Prest, Alessandro Traci, F. Perotti, P. A. Caraveo, I. Donnarumma, Y. Evangelista, E. Moretti, Massimo Frutti, G. Valentini, Claudio Labanti, F. Liello, F. Fornari, L. A. Antonelli, G. De Paris, C. Pittori, M. Tavani, D. Zanello, F. Lazzarotto, G. Di Persio, L. Pacciani, A. Rappoldi, T. Froysland, G. Fanari, Martino Marisaldi, F. Fuschino, Geiland Porrovecchio, A. Argan, A. Morselli, P. Giommi, M. Pilia, P. Lipari, Andrea Bulgarelli, V. Cocco, S. Stellato, C. Pontoni, E. Morelli, M. Trifoglio, F. Longo, P. Picozza, E. Striani, S. Vercellone, T. Contessi, G. Piano, A. W. Chen, I. Lapshov, E. Del Monte, G. Pucella, S. Sabatini, A. Mauri, Sandro Mereghetti, A. Pellizzoni, E. Costa, M. Feroci, A. Giuliani, M. Fiorini, Elena M. Rossi, S. Colafrancesco, M. Mastropietro, V. Vittorini, M. Cardillo, Arnaud Ferrari, P. Santolamazza, P. W. Cattaneo, M. Rapisarda, P. Soffitta, E. Vallazza, M. Galli, F. Tamburelli, F. Verrecchia, F., Verrecchia, C., Pittori, A. W., Chen, A., Bulgarelli, M., Tavani, F., Lucarelli, P., Giommi, S., Vercellone, A., Pellizzoni, A., Giuliani, Longo, Francesco, BARBIELLINI AMIDEI, Guido, M., Trifoglio, F., Gianotti, A., Argan, L. A., Antonelli, P., Caraveo, M., Cardillo, P. W., Cattaneo, V., Cocco, S., Colafrancesco, T., Contessi, E., Costa, E., Del Monte, G., De Pari, G., Di Cocco, G., Di Persio, I., Donnarumma, Y., Evangelista, G., Fanari, M., Feroci, A., Ferrari, M., Fiorini, F., Fornari, F., Fuschino, T., Froysland, M., Frutti, M., Galli, C., Labanti, I., Lapshov, F., Lazzarotto, F., Liello, P., Lipari, E., Mattaini, M., Marisaldi, M., Mastropietro, A., Mauri, F., Mauri, S., Mereghetti, E., Morelli, Moretti, Elena, A., Morselli, L., Pacciani, F., Perotti, G., Piano, P., Picozza, M., Pilia, C., Pontoni, G., Porrovecchio, M., Prest, R., Primavera, G., Pucella, M., Rapisarda, A., Rappoldi, E., Rossi, A., Rubini, S., Sabatini, P., Santolamazza, P., Soffitta, S., Stellato, E., Striani, F., Tamburelli, A., Traci, A., Troi, E., Vallazza, V., Vittorini, D., Zanello, L., Salotti, and G., Valentini

Subjects
catalog, Brightness, FOS: Physical sciences, Field of view, Astrophysics, gamma-ray source, gamma rays: galaxies, galaxie [gamma rays], Blazar, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Nebula, Crab Pulsar, Mode (statistics), Gamma ray, Astronomy and Astrophysics, gamma rays: general, Galactic plane, silicon tracker, AGILE satellite, Space and Planetary Science, catalogs, Astrophysics - High Energy Astrophysical Phenomena, general [gamma rays]
Abstract

We present a variability study of a sample of bright gamma-ray (30 MeV -- 50 GeV) sources. This sample is an extension of the first AGILE catalogue of gamma-ray sources (1AGL), obtained using the complete set of AGILE observations in pointing mode performed during a 2.3 year period from July 9, 2007 until October 30, 2009. The dataset of AGILE pointed observations covers a long time interval and its gamma-ray data archive is useful for monitoring studies of medium-to-high brightness gamma-ray sources. In the analysis reported here, we used data obtained with an improved event filter that covers a wider field of view, on a much larger (about 27.5 months) dataset, integrating data on observation block time scales, which mostly range from a few days to thirty days. The data processing resulted in a better characterized source list than 1AGL was, and includes 54 sources, 7 of which are new high galactic latitude (|BII| >= 5) sources, 8 are new sources on the galactic plane, and 20 sources from the previous catalogue with revised positions. Eight 1AGL sources (2 high-latitude and 6 on the galactic plane) were not detected in the final processing either because of low OB exposure and/or due to their position in complex galactic regions. We report the results in a catalogue of all the detections obtained in each single OB, including the variability results for each of these sources. In particular, we found that 12 sources out of 42 or 11 out of 53 are variable, depending on the variability index used, where 42 and 53 are the number of sources for which these indices could be calculated. Seven of the 11 variable sources are blazars, the others are Crab pulsar+nebula, LS I +61{\deg}303, Cyg X-3, and 1AGLR J2021+4030., Comment: 30 pages, 12 figures

10. Discovery of powerful gamma-ray flares from the Crab Nebula.

Author

Tavani M, Bulgarelli A, Vittorini V, Pellizzoni A, Striani E, Caraveo P, Weisskopf MC, Tennant A, Pucella G, Trois A, Costa E, Evangelista Y, Pittori C, Verrecchia F, Del Monte E, Campana R, Pilia M, De Luca A, Donnarumma I, Horns D, Ferrigno C, Heinke CO, Trifoglio M, Gianotti F, Vercellone S, Argan A, Barbiellini G, Cattaneo PW, Chen AW, Contessi T, D'Ammando F, DePris G, Di Cocco G, Di Persio G, Feroci M, Ferrari A, Galli M, Giuliani A, Giusti M, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Fuschino F, Marisaldi M, Mereghetti S, Morelli E, Moretti E, Morselli A, Pacciani L, Perotti F, Piano G, Picozza P, Prest M, Rapisarda M, Rappoldi A, Rubini A, Sabatini S, Soffitta P, Vallazza E, Zambra A, Zanello D, Lucarelli F, Santolamazza P, Giommi P, Salotti L, and Bignami GF

Abstract

The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (100 mega-electron volts to 10 giga-electron volts) flares observed by the AGILE satellite in September 2010 and October 2007. In both cases, the total gamma-ray flux increased by a factor of three compared with the non-flaring flux. The flare luminosity and short time scale favor an origin near the pulsar, and we discuss Chandra Observatory x-ray and Hubble Space Telescope optical follow-up observations of the nebula. Our observations challenge standard models of nebular emission and require power-law acceleration by shock-driven plasma wave turbulence within an approximately 1-day time scale.

Published
2011
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11. Detection of gamma-ray emission from the Vela pulsar wind nebula with AGILE.

Author

Pellizzoni A, Trois A, Tavani M, Pilia M, Giuliani A, Pucella G, Esposito P, Sabatini S, Piano G, Argan A, Barbiellini G, Bulgarelli A, Burgay M, Caraveo P, Cattaneo PW, Chen AW, Cocco V, Contessi T, Costa E, D'Ammando F, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Fuschino F, Galli M, Gianotti F, Hotan A, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mastropietro M, Mereghetti S, Moretti E, Morselli A, Pacciani L, Palfreyman J, Perotti F, Picozza P, Pittori C, Possenti A, Prest M, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Santolamazza P, Scalise E, Soffitta P, Striani E, Trifoglio M, Vallazza E, Vercellone S, Verrecchia F, Vittorini V, Zambra A, Zanello D, Giommi P, Colafrancesco S, Antonelli A, Salotti L, D'Amico N, and Bignami GF

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.

Published
2010
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12. Extreme particle acceleration in the microquasar Cygnus X-3.

Author

Tavani M, Bulgarelli A, Piano G, Sabatini S, Striani E, Evangelista Y, Trois A, Pooley G, Trushkin S, Nizhelskij NA, McCollough M, Koljonen KI, Pucella G, Giuliani A, Chen AW, Costa E, Vittorini V, Trifoglio M, Gianotti F, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Cocco V, Contessi T, D'Ammando F, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Feroci M, Ferrari A, Fuschino F, Galli M, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Mattaini E, Marisaldi M, Mastropietro M, Mauri A, Mereghetti S, Morelli E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Pilia M, Prest M, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Scalise E, Soffitta P, Vallazza E, Vercellone S, Zambra A, Zanello D, Pittori C, Verrecchia F, Giommi P, Colafrancesco S, Santolamazza P, Antonelli A, and Salotti L

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.

Published
2009
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