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97 results on '"Striani E"'

1. The first fermi large area telescope catalog of gamma-ray pulsars

Author: Abdo, A. A., Ackermann, M., Ajello, M., Atwood, W.B., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Baring, M. G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Buson, S., Caliandro, G. A., Cameron, R. A., Camilo, F., Caraveo, P. A., Casandjian, J. M., Cecchi, C., Celik, O., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cognard, I., Cohen-Tanugi, J., Cominsky, L. R., Conrad, J., Corbet, R., Cutini, S., den Hartog, P. R., Dermer, C. D., de Angelis, A., de Luca, A., de Palma, F., Digel, S. W., Dormody, M., do Couto e Silva, E., Drell, P. S., Dubois, R., Dumora, D., Espinoza, C., Farnier, C., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Focke, W. B., Fortin, P., Frailis, M., Freire, P. C. C., 深沢, 泰司, Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giavitto, G., Giebels, B., Giglietto, N., Giommi, P., Giordano, F., Glanzman, T., Godfrey, G., Gotthelf, E. V., Grenier, I. A., Grondin, M.-H., Grove, J. E., Guillemot, L., Guiriec, S., Gwon, C., 花畑, 義隆, Harding, A. K., 林田, 将明, Hays, E., Hughes, R. E., Jackson, M. S., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, T. J., Johnson, W. N., Johnston, S., 釜江, 常好, Kanbach, G., Kaspi, V. M., 片桐, 秀明, 片岡, 淳, 河合, 誠之, Kerr, M., Knodlseder, J., Kocian, M. L., Kramer, M., Kuss, M., Lande, J., Latronico, L., Lemoine-Goumard, M., Livingstone, M., Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Lyne, A. G., Madejski, G. M., Makeev, A., Manchester, R. N., Marelli, M., Mazziotta, M. N., McConville, W., McEnery, J. E., McGlynn, S., Meurer, C., Michelson, P. F., Mineo, T., Mitthumsiri, W., 水野, 恒史, Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nakamori, T., Nolan, P. L., Norris, J. P., Noutsos, A., Nuss, E., 大杉, 節, Omodei, N., Orlando, E., Ormes, J. F., 尾崎, 正伸, Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce-Rollins, M., Piron, F., Porter, T. A., Raino, S., Rando, R., Ransom, S. M., Ray, P. S., Razzano, M., Rea, N., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Rodriguez, A. Y., Romani, R. W., Roth, M., Ryde, F., Sadrozinski, H. F.-W., Sanchez, D., Sander, A., Saz Parkinson, P. M., Scargle, J. D., Schalk, T. L., Sellerholm, A., Sgro, C., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Stappers, B. W., Starck, J.-L., Striani, E., Strickman, M. S., Strong, A. W., Suson, D. J., 田島, 宏康, 高橋, 弘充, 高橋, 忠幸, 田中, 孝明, Thayer, J. B., Thayer, J. G., Theureau, G., Thompson, D. J., Thorsett, S. E., Tibaldo, L., Tibolla, O., Torres, D. F., Tosti, G., Tramacere, A., 内山, 泰伸, Fukazawa, Y., Hanabata, Y., Hayashida, M., Kamae, T., Katagiri, H., Kataoka, J., Kawai, N., Mizuno, T., Ohsugi, T., Ozaki, Masanobu, Tajima, H., Takahashi, H., Takahashi, Tadayuki, Tanaka, T., Uchiyama, Yasunobu, Abdo, A. A., Ackermann, M., Ajello, M., Atwood, W.B., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Baring, M. G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Buson, S., Caliandro, G. A., Cameron, R. A., Camilo, F., Caraveo, P. A., Casandjian, J. M., Cecchi, C., Celik, O., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cognard, I., Cohen-Tanugi, J., Cominsky, L. R., Conrad, J., Corbet, R., Cutini, S., den Hartog, P. R., Dermer, C. D., de Angelis, A., de Luca, A., de Palma, F., Digel, S. W., Dormody, M., do Couto e Silva, E., Drell, P. S., Dubois, R., Dumora, D., Espinoza, C., Farnier, C., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Focke, W. B., Fortin, P., Frailis, M., Freire, P. C. C., 深沢, 泰司, Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giavitto, G., Giebels, B., Giglietto, N., Giommi, P., Giordano, F., Glanzman, T., Godfrey, G., Gotthelf, E. V., Grenier, I. A., Grondin, M.-H., Grove, J. E., Guillemot, L., Guiriec, S., Gwon, C., 花畑, 義隆, Harding, A. K., 林田, 将明, Hays, E., Hughes, R. E., Jackson, M. S., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, T. J., Johnson, W. N., Johnston, S., 釜江, 常好, Kanbach, G., Kaspi, V. M., 片桐, 秀明, 片岡, 淳, 河合, 誠之, Kerr, M., Knodlseder, J., Kocian, M. L., Kramer, M., Kuss, M., Lande, J., Latronico, L., Lemoine-Goumard, M., Livingstone, M., Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Lyne, A. G., Madejski, G. M., Makeev, A., Manchester, R. N., Marelli, M., Mazziotta, M. N., McConville, W., McEnery, J. E., McGlynn, S., Meurer, C., Michelson, P. F., Mineo, T., Mitthumsiri, W., 水野, 恒史, Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nakamori, T., Nolan, P. L., Norris, J. P., Noutsos, A., Nuss, E., 大杉, 節, Omodei, N., Orlando, E., Ormes, J. F., 尾崎, 正伸, Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce-Rollins, M., Piron, F., Porter, T. A., Raino, S., Rando, R., Ransom, S. M., Ray, P. S., Razzano, M., Rea, N., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Rodriguez, A. Y., Romani, R. W., Roth, M., Ryde, F., Sadrozinski, H. F.-W., Sanchez, D., Sander, A., Saz Parkinson, P. M., Scargle, J. D., Schalk, T. L., Sellerholm, A., Sgro, C., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Stappers, B. W., Starck, J.-L., Striani, E., Strickman, M. S., Strong, A. W., Suson, D. J., 田島, 宏康, 高橋, 弘充, 高橋, 忠幸, 田中, 孝明, Thayer, J. B., Thayer, J. G., Theureau, G., Thompson, D. J., Thorsett, S. E., Tibaldo, L., Tibolla, O., Torres, D. F., Tosti, G., Tramacere, A., 内山, 泰伸, Fukazawa, Y., Hanabata, Y., Hayashida, M., Kamae, T., Katagiri, H., Kataoka, J., Kawai, N., Mizuno, T., Ohsugi, T., Ozaki, Masanobu, Tajima, H., Takahashi, H., Takahashi, Tadayuki, Tanaka, T., and Uchiyama, Yasunobu
Abstract: 著者人数：217名, Accepted: 2010-02-13
Published: 2015

2. The blob crashes into the mirror: modelling the exceptional gamma-ray flaring activity of 3C 454.3 in November 2010

Author: Vittorini, V., Tavani, M., Cavaliere, A., Striani, E., Vercellone, S., Vittorini, V., Tavani, M., Cavaliere, A., Striani, E., and Vercellone, S.
Abstract: We focus on the exceptional flaring activity of 3C 454.3 in November 2010 and we discuss a theoretical framework addressing all data in their overall evolution. For two weeks the source has shown a plateau of enhanced GeV emission preceding a sudden major flare lasting about 3 days before decaying. The gamma-ray flare onset is abrupt (about 6 hours), and is characterized by a prominent "Compton dominance" with the GeV flux exceeding the pre-flare values by a factor of 4-5, whereas the optical and X-ray fluxes increased only by a factor 2. We explore two alternatives. Case 1, with high-energy emission originating within the BLR; and Case 2, with most of it produced outside. We show that Case 1 has considerable problems in explaining the whole set of multifrequency data. Case 2, instead, leads to a consistent and interesting interpretation based on the enhanced inverse Compton radiation that is produced as the jet crashes onto a mirror cloud positioned at few parsec from the BH. This model explains the gamma-ray vs. optical/X-ray behavior of 3C 454.3, including the otherwise puzzling phenomena such as the prominent "orphan" optical flare, and the enhanced line emission with no appreciable gamma-ray counterpart that preceded the GeV flare. It also accounts for the delayed onset of the latter on top of the long plateau. Our modelling of the exceptional 3C 454.3 gamma-ray flare shows that, while emission inside the canonical BLR is problematic, major and rapid variations can be produced at parsec scales with moderate bulk Lorentz factors $\Gamma\approx 15$., Comment: Submitted: February 21, 2014. Accepted: July 19, 2014
Published: 2014
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3. The blob crashes into the mirror: modelling the exceptional gamma-ray flaring activity of 3C 454.3 in November 2010

Author: Vittorini, V., Tavani, M., Cavaliere, A., Striani, E., Vercellone, S., Vittorini, V., Tavani, M., Cavaliere, A., Striani, E., and Vercellone, S.
Abstract: We focus on the exceptional flaring activity of 3C 454.3 in November 2010 and we discuss a theoretical framework addressing all data in their overall evolution. For two weeks the source has shown a plateau of enhanced GeV emission preceding a sudden major flare lasting about 3 days before decaying. The gamma-ray flare onset is abrupt (about 6 hours), and is characterized by a prominent "Compton dominance" with the GeV flux exceeding the pre-flare values by a factor of 4-5, whereas the optical and X-ray fluxes increased only by a factor 2. We explore two alternatives. Case 1, with high-energy emission originating within the BLR; and Case 2, with most of it produced outside. We show that Case 1 has considerable problems in explaining the whole set of multifrequency data. Case 2, instead, leads to a consistent and interesting interpretation based on the enhanced inverse Compton radiation that is produced as the jet crashes onto a mirror cloud positioned at few parsec from the BH. This model explains the gamma-ray vs. optical/X-ray behavior of 3C 454.3, including the otherwise puzzling phenomena such as the prominent "orphan" optical flare, and the enhanced line emission with no appreciable gamma-ray counterpart that preceded the GeV flare. It also accounts for the delayed onset of the latter on top of the long plateau. Our modelling of the exceptional 3C 454.3 gamma-ray flare shows that, while emission inside the canonical BLR is problematic, major and rapid variations can be produced at parsec scales with moderate bulk Lorentz factors $\Gamma\approx 15$., Comment: Submitted: February 21, 2014. Accepted: July 19, 2014
Published: 2014
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4. Calibration of AGILE-GRID with in-flight data and Monte Carlo simulations

Author: Chen, A. W., Argan, A., Bulgarelli, A., Cattaneo, P. W., Contessi, T., Giuliani, A., Pittori, C., Pucella, G., Tavani, M., Trois, A., Verrecchia, F., Barbiellini, G., Caraveo, P., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fioretti, V., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Giommi, P., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Lucarelli, F., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, Elena, Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Striani, E., Trifoglio, M., Valentini, G., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Chen, A. W., Argan, A., Bulgarelli, A., Cattaneo, P. W., Contessi, T., Giuliani, A., Pittori, C., Pucella, G., Tavani, M., Trois, A., Verrecchia, F., Barbiellini, G., Caraveo, P., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fioretti, V., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Giommi, P., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Lucarelli, F., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, Elena, Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Striani, E., Trifoglio, M., Valentini, G., Vallazza, E., Vercellone, S., Vittorini, V., and Zanello, D.
Abstract: Context. AGILE is a γ-ray astrophysics mission which has been in orbit since 23 April 2007 and continues to operate reliably. The γ-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 γ-ray energies and incident angles, including background rejection filters and Kalman filter-based γ-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 Center since November 25, 2011, while the changes in the analysis software will be distributed in an upcoming release., QC 20131029
Published: 2013
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5. An updated list of AGILE bright gamma-ray sources and their variability in pointing mode

Author: Verrecchia, F., Pittori, C., Chen, A. W., Bulgarelli, A., Tavani, M., Lucarelli, F., Giommi, P., Vercellone, S., Pellizzoni, A., Giuliani, A., Longo, F., Barbiellini, G., Trifoglio, M., Gianotti, F., Argan, A., Antonelli, L. A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Cocco, V., Colafrancesco, S., Contessi, T., Costa, E., 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., 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., Prest, M., Primavera, R., Pucella, G., Rapisarda, M., Rappoldi, A., Rossi, E., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Stellato, S., Striani, E., Tamburelli, F., Traci, A., Trois, A., Vallazza, E., Vittorini, V., Zanello, D., Salotti, L., Valentini, G., Verrecchia, F., Pittori, C., Chen, A. W., Bulgarelli, A., Tavani, M., Lucarelli, F., Giommi, P., Vercellone, S., Pellizzoni, A., Giuliani, A., Longo, F., Barbiellini, G., Trifoglio, M., Gianotti, F., Argan, A., Antonelli, L. A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Cocco, V., Colafrancesco, S., Contessi, T., Costa, E., 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., 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., Prest, M., Primavera, R., Pucella, G., Rapisarda, M., Rappoldi, A., Rossi, E., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Stellato, S., Striani, E., Tamburelli, F., Traci, A., Trois, A., Vallazza, E., Vittorini, V., Zanello, D., Salotti, L., and Valentini, G.
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
Published: 2013
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6. Modelling the Kinked Jet of the Crab Nebula

Author: Mignone, A., Striani, E., Tavani, M., Ferrari, A., Mignone, A., Striani, E., Tavani, M., and Ferrari, A.
Abstract: We investigate the dynamical propagation of the South-East jet from the Crab pulsar interacting with supernova ejecta by means of three-dimensional relativistic MHD numerical simulations with the PLUTO code. The initial jet structure is set up from the inner regions of the Crab Nebula. We study the evolution of hot, relativistic hollow outflows initially carrying a purely azimuthal magnetic field. Our jet models are characterized by different choices of the outflow magnetization ($\sigma$ parameter) and the bulk Lorentz factor ($\gamma_{j}$). We show that the jet is heavily affected by the growth of current-driven kink instabilities causing considerable deflection throughout its propagation length. This behavior is partially stabilized by the combined action of larger flow velocities and/or reduced magnetic field strengths. We find that our best jet models are characterized by relatively large values of $\sigma$ ($\gtrsim 1$) and small values of $\gamma_{j}\simeq 2$. Our results are in good agreement with the recent X-ray (\textit{Chandra}) data of the Crab Nebula South-East jet indicating that the jet changes direction of propagation on a time scale of the order of few years. The 3D models presented here may have important implications in the investigation of particle acceleration in relativistic outflows., Comment: 15 pages, 20 figures
Published: 2013
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7. Calibration of AGILE-GRID with In-Flight Data and Monte Carlo Simulations

Author: Chen, Andrew W., Argan, A., Bulgarelli, A., Cattaneo, P. W., Contessi, T., Giuliani, A., Pittori, C., Pucella, G., Tavani, M., Trois, A., Verrecchia, F., Barbiellini, G., Caraveo, P., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fioretti, V., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Giommi, P., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Lucarelli, F., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Striani, E., Trifoglio, M., Valentini, G., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Chen, Andrew W., Argan, A., Bulgarelli, A., Cattaneo, P. W., Contessi, T., Giuliani, A., Pittori, C., Pucella, G., Tavani, M., Trois, A., Verrecchia, F., Barbiellini, G., Caraveo, P., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fioretti, V., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Giommi, P., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Lucarelli, F., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Striani, E., Trifoglio, M., Valentini, G., Vallazza, E., Vercellone, S., Vittorini, V., and Zanello, D.
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
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8. The Surprising Crab Nebula

Author: Striani, E., Tavani, M., Vittorini, V., Striani, E., Tavani, M., and Vittorini, V.
Abstract: We will present our study of the flux and spectral variability of the Crab above 100 MeV on different timescales ranging from days to weeks. In addition to the four main intense and day-long flares detected by AGILE and Fermi-LAT between Sept. 2007 and Sept. 2012, we find evidence for week-long and less intense episodes of enhanced gamma-ray emission that we call "waves". Statistically significant "waves" show timescales of 1-2 weeks, and can occur by themselves or in association with shorter flares. The Sept. - Oct. 2007 gamma-ray enhancement episode detected by AGILE shows both "wave" and flaring behavior. We extend our analysis to the publicly available Fermi-LAT dataset and show that several additional "wave" episodes can be identified. We discuss the spectral properties of the September 2007 "wave"/flare event and show that the physical properties of the "waves" are intermediate between steady and flaring states. Plasma instabilities inducing "waves" appear to involve spatial distances $ l \sim 10^{16} \,$cm and enhanced magnetic fields $B \sim (0.5 - 1)\,$}mG. Day-long flares are characterized by smaller distances and larger local magnetic fields. Typically, the deduced total energy associated with the "wave" phenomenon ($E_w \sim 10^{42} \, \rm erg$, where $E_w$ is the kinetic energy of the emitting particles) is comparable with that associated to the flares, and can reach a few percent of the total available pulsar spindown energy. Most likely, flares and waves are the product of the same class of plasma instabilities that we show acting on different timescales and radiation intensities., Comment: 2012 Fermi Symposium proceedings - eConf C121028
Published: 2013

9. Gamma-ray observations of Cygnus X-1 above 100 MeV in the hard and soft states

Author: Sabatini, S., Tavani, M., Coppi, P., Pooley, G., Del Santo, M., Campana, R., Chen, A., Evangelista, Y., Piano, G., Bulgarelli, A., Cattaneo, P. W., Colafrancesco, S., Del Monte, E., Giuliani, A., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pilia, M., Striani, E., Trifoglio, M., Vercellone, S., Sabatini, S., Tavani, M., Coppi, P., Pooley, G., Del Santo, M., Campana, R., Chen, A., Evangelista, Y., Piano, G., Bulgarelli, A., Cattaneo, P. W., Colafrancesco, S., Del Monte, E., Giuliani, A., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pilia, M., Striani, E., Trifoglio, M., and Vercellone, S.
Abstract: We present the results of multi-year gamma-ray observations by the AGILE satellite of the black hole binary system Cygnus X-1. In a previous investigation we focused on gamma-ray observations of Cygnus X-1 in the hard state during the period mid-2007/2009. Here we present the results of the gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 carried out for which includes a remarkably prolonged `soft state' phase (June 2010 -- May 2011). Previous 1--10 MeV observations of Cyg X-1 in this state hinted at a possible existence of a non-thermal particle component with substantial modifications of the Comptonized emission from the inner accretion disk. Our AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1, provide a significant upper limit for gamma-ray emission above 100 MeV of F_soft < 20 x 10^{-8} ph/cm^2/s, excluding the existence of prominent non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We discuss theoretical implications of our findings in the context of high-energy emission models of black hole accretion. We also discuss possible gamma-ray flares detected by AGILE. In addition to a previously reported episode observed by AGILE in October 2009 during the hard state, we report a weak but important candidate for enhanced emission which occurred at the end of June 2010 (2010-06-30 10:00 - 2010-07-02 10:00 UT) exactly in coincidence with a hard-to-soft state transition and before an anomalous radio flare. An appendix summarizes all previous high-energy observations and possible detections of Cygnus X-1 above 1 MeV., Comment: 16 pages, 12 figures, 1 table, accepted for publication in ApJ
Published: 2013
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10. Variable gamma-ray emission from the Crab Nebula: short flares and long 'waves'

Author: Striani, E., Tavani, M., Vittorini, V., Donnarumma, I., Giuliani, A., Pucella, G., Argan, A., Bulgarelli, A., Colafrancesco, S., Cardillo, M., Costa, E., Del Monte, E., Ferrari, A., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Pittori, C., Rapisarda, M., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vercellone, S., Verrecchia, F., Striani, E., Tavani, M., Vittorini, V., Donnarumma, I., Giuliani, A., Pucella, G., Argan, A., Bulgarelli, A., Colafrancesco, S., Cardillo, M., Costa, E., Del Monte, E., Ferrari, A., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Pittori, C., Rapisarda, M., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vercellone, S., and Verrecchia, F.
Abstract: Gamma-ray emission from the Crab Nebula has been recently shown to be unsteady. In this paper, we study the flux and spectral variability of the Crab above 100 MeV on different timescales ranging from days to weeks. In addition to the four main intense and day-long flares detected by AGILE and Fermi-LAT between Sept. 2007 and Sept. 2012, we find evidence for week-long and less intense episodes of enhanced gamma-ray emission that we call "waves". Statistically significant "waves" show timescales of 1-2 weeks, and can occur by themselves or in association with shorter flares. We present a refined flux and spectral analysis of the Sept. - Oct. 2007 gamma-ray enhancement episode detected by AGILE that shows both "wave" and flaring behavior. We extend our analysis to the publicly available Fermi-LAT dataset and show that several additional "wave" episodes can be identified. We discuss the spectral properties of the September 2007 "wave"/flare event and show that the physical properties of the "waves" are intermediate between steady and flaring states. Plasma instabilities inducing "waves" appear to involve spatial distances l \sim 10^{16} cm and enhanced magnetic fields B \sim (0.5 - 1) mG. Day-long flares are characterized by smaller distances and larger local magnetic fields. Typically, the deduced total energy associated with the "wave" phenomenon (E_w \sim 10^{42} erg, where E_w is the kinetic energy of the emitting particles) is comparable with that associated to the flares, and can reach a few percent of the total available pulsar spindown energy. Most likely, flares and waves are the product of the same class of plasma instabilities that we show acting on different timescales and radiation intensities., Comment: 11 pages, 10 figures
Published: 2013
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11. An updated list of AGILE bright gamma-ray sources and their variability in pointing mode

Author: Verrecchia, F., Pittori, C., Chen, A. W., Bulgarelli, A., Tavani, M., Lucarelli, F., Giommi, P., Vercellone, S., Pellizzoni, A., Giuliani, A., Longo, F., Barbiellini, G., Trifoglio, M., Gianotti, F., Argan, A., Antonelli, L. A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Cocco, V., Colafrancesco, S., Contessi, T., Costa, E., 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., 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., Prest, M., Primavera, R., Pucella, G., Rapisarda, M., Rappoldi, A., Rossi, E., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Stellato, S., Striani, E., Tamburelli, F., Traci, A., Trois, A., Vallazza, E., Vittorini, V., Zanello, D., Salotti, L., Valentini, G., Verrecchia, F., Pittori, C., Chen, A. W., Bulgarelli, A., Tavani, M., Lucarelli, F., Giommi, P., Vercellone, S., Pellizzoni, A., Giuliani, A., Longo, F., Barbiellini, G., Trifoglio, M., Gianotti, F., Argan, A., Antonelli, L. A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Cocco, V., Colafrancesco, S., Contessi, T., Costa, E., 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., 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., Prest, M., Primavera, R., Pucella, G., Rapisarda, M., Rappoldi, A., Rossi, E., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Stellato, S., Striani, E., Tamburelli, F., Traci, A., Trois, A., Vallazza, E., Vittorini, V., Zanello, D., Salotti, L., and Valentini, G.
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
Published: 2013
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12. Calibration of AGILE-GRID with In-Flight Data and Monte Carlo Simulations

Author: Chen, Andrew W., Argan, A., Bulgarelli, A., Cattaneo, P. W., Contessi, T., Giuliani, A., Pittori, C., Pucella, G., Tavani, M., Trois, A., Verrecchia, F., Barbiellini, G., Caraveo, P., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fioretti, V., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Giommi, P., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Lucarelli, F., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Striani, E., Trifoglio, M., Valentini, G., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Chen, Andrew W., Argan, A., Bulgarelli, A., Cattaneo, P. W., Contessi, T., Giuliani, A., Pittori, C., Pucella, G., Tavani, M., Trois, A., Verrecchia, F., Barbiellini, G., Caraveo, P., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fioretti, V., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Giommi, P., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Lucarelli, F., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Santolamazza, P., Soffitta, P., Striani, E., Trifoglio, M., Valentini, G., Vallazza, E., Vercellone, S., Vittorini, V., and Zanello, D.
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
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13. Modelling the Kinked Jet of the Crab Nebula

Author: Mignone, A., Striani, E., Tavani, M., Ferrari, A., Mignone, A., Striani, E., Tavani, M., and Ferrari, A.
Abstract: We investigate the dynamical propagation of the South-East jet from the Crab pulsar interacting with supernova ejecta by means of three-dimensional relativistic MHD numerical simulations with the PLUTO code. The initial jet structure is set up from the inner regions of the Crab Nebula. We study the evolution of hot, relativistic hollow outflows initially carrying a purely azimuthal magnetic field. Our jet models are characterized by different choices of the outflow magnetization ($\sigma$ parameter) and the bulk Lorentz factor ($\gamma_{j}$). We show that the jet is heavily affected by the growth of current-driven kink instabilities causing considerable deflection throughout its propagation length. This behavior is partially stabilized by the combined action of larger flow velocities and/or reduced magnetic field strengths. We find that our best jet models are characterized by relatively large values of $\sigma$ ($\gtrsim 1$) and small values of $\gamma_{j}\simeq 2$. Our results are in good agreement with the recent X-ray (\textit{Chandra}) data of the Crab Nebula South-East jet indicating that the jet changes direction of propagation on a time scale of the order of few years. The 3D models presented here may have important implications in the investigation of particle acceleration in relativistic outflows., Comment: 15 pages, 20 figures
Published: 2013
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14. The Surprising Crab Nebula

Author: Striani, E., Tavani, M., Vittorini, V., Striani, E., Tavani, M., and Vittorini, V.
Abstract: We will present our study of the flux and spectral variability of the Crab above 100 MeV on different timescales ranging from days to weeks. In addition to the four main intense and day-long flares detected by AGILE and Fermi-LAT between Sept. 2007 and Sept. 2012, we find evidence for week-long and less intense episodes of enhanced gamma-ray emission that we call "waves". Statistically significant "waves" show timescales of 1-2 weeks, and can occur by themselves or in association with shorter flares. The Sept. - Oct. 2007 gamma-ray enhancement episode detected by AGILE shows both "wave" and flaring behavior. We extend our analysis to the publicly available Fermi-LAT dataset and show that several additional "wave" episodes can be identified. We discuss the spectral properties of the September 2007 "wave"/flare event and show that the physical properties of the "waves" are intermediate between steady and flaring states. Plasma instabilities inducing "waves" appear to involve spatial distances $ l \sim 10^{16} \,$cm and enhanced magnetic fields $B \sim (0.5 - 1)\,$}mG. Day-long flares are characterized by smaller distances and larger local magnetic fields. Typically, the deduced total energy associated with the "wave" phenomenon ($E_w \sim 10^{42} \, \rm erg$, where $E_w$ is the kinetic energy of the emitting particles) is comparable with that associated to the flares, and can reach a few percent of the total available pulsar spindown energy. Most likely, flares and waves are the product of the same class of plasma instabilities that we show acting on different timescales and radiation intensities., Comment: 2012 Fermi Symposium proceedings - eConf C121028
Published: 2013

15. Gamma-ray observations of Cygnus X-1 above 100 MeV in the hard and soft states

Author: Sabatini, S., Tavani, M., Coppi, P., Pooley, G., Del Santo, M., Campana, R., Chen, A., Evangelista, Y., Piano, G., Bulgarelli, A., Cattaneo, P. W., Colafrancesco, S., Del Monte, E., Giuliani, A., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pilia, M., Striani, E., Trifoglio, M., Vercellone, S., Sabatini, S., Tavani, M., Coppi, P., Pooley, G., Del Santo, M., Campana, R., Chen, A., Evangelista, Y., Piano, G., Bulgarelli, A., Cattaneo, P. W., Colafrancesco, S., Del Monte, E., Giuliani, A., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pilia, M., Striani, E., Trifoglio, M., and Vercellone, S.
Abstract: We present the results of multi-year gamma-ray observations by the AGILE satellite of the black hole binary system Cygnus X-1. In a previous investigation we focused on gamma-ray observations of Cygnus X-1 in the hard state during the period mid-2007/2009. Here we present the results of the gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 carried out for which includes a remarkably prolonged `soft state' phase (June 2010 -- May 2011). Previous 1--10 MeV observations of Cyg X-1 in this state hinted at a possible existence of a non-thermal particle component with substantial modifications of the Comptonized emission from the inner accretion disk. Our AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1, provide a significant upper limit for gamma-ray emission above 100 MeV of F_soft < 20 x 10^{-8} ph/cm^2/s, excluding the existence of prominent non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We discuss theoretical implications of our findings in the context of high-energy emission models of black hole accretion. We also discuss possible gamma-ray flares detected by AGILE. In addition to a previously reported episode observed by AGILE in October 2009 during the hard state, we report a weak but important candidate for enhanced emission which occurred at the end of June 2010 (2010-06-30 10:00 - 2010-07-02 10:00 UT) exactly in coincidence with a hard-to-soft state transition and before an anomalous radio flare. An appendix summarizes all previous high-energy observations and possible detections of Cygnus X-1 above 1 MeV., Comment: 16 pages, 12 figures, 1 table, accepted for publication in ApJ
Published: 2013
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16. Variable gamma-ray emission from the Crab Nebula: short flares and long 'waves'

Author: Striani, E., Tavani, M., Vittorini, V., Donnarumma, I., Giuliani, A., Pucella, G., Argan, A., Bulgarelli, A., Colafrancesco, S., Cardillo, M., Costa, E., Del Monte, E., Ferrari, A., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Pittori, C., Rapisarda, M., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vercellone, S., Verrecchia, F., Striani, E., Tavani, M., Vittorini, V., Donnarumma, I., Giuliani, A., Pucella, G., Argan, A., Bulgarelli, A., Colafrancesco, S., Cardillo, M., Costa, E., Del Monte, E., Ferrari, A., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Pittori, C., Rapisarda, M., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vercellone, S., and Verrecchia, F.
Abstract: Gamma-ray emission from the Crab Nebula has been recently shown to be unsteady. In this paper, we study the flux and spectral variability of the Crab above 100 MeV on different timescales ranging from days to weeks. In addition to the four main intense and day-long flares detected by AGILE and Fermi-LAT between Sept. 2007 and Sept. 2012, we find evidence for week-long and less intense episodes of enhanced gamma-ray emission that we call "waves". Statistically significant "waves" show timescales of 1-2 weeks, and can occur by themselves or in association with shorter flares. We present a refined flux and spectral analysis of the Sept. - Oct. 2007 gamma-ray enhancement episode detected by AGILE that shows both "wave" and flaring behavior. We extend our analysis to the publicly available Fermi-LAT dataset and show that several additional "wave" episodes can be identified. We discuss the spectral properties of the September 2007 "wave"/flare event and show that the physical properties of the "waves" are intermediate between steady and flaring states. Plasma instabilities inducing "waves" appear to involve spatial distances l \sim 10^{16} cm and enhanced magnetic fields B \sim (0.5 - 1) mG. Day-long flares are characterized by smaller distances and larger local magnetic fields. Typically, the deduced total energy associated with the "wave" phenomenon (E_w \sim 10^{42} erg, where E_w is the kinetic energy of the emitting particles) is comparable with that associated to the flares, and can reach a few percent of the total available pulsar spindown energy. Most likely, flares and waves are the product of the same class of plasma instabilities that we show acting on different timescales and radiation intensities., Comment: 11 pages, 10 figures
Published: 2013
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17. Upper limits on the high-energy emission from gamma-ray bursts observed by AGILE-GRID

Author: Longo, F., Moretti, E., Nava, L., Desiante, R., Olivo, M., Del Monte, E., Rappoldi, A., Fuschino, F., Marisaldi, M., Giuliani, A., Cutini, S., Feroci, M., Costa, E., Pittori, C., Tavani, M., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Chen, A. W., D'Ammando, F., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Fiorini, M., Galli, M., Gianotti, F., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Antonelli, L. A., Colafrancesco, S., Giommi, P., Santolamazza, P., Verrecchia, F., Lucarelli, F., Salotti, L., Longo, F., Moretti, E., Nava, L., Desiante, R., Olivo, M., Del Monte, E., Rappoldi, A., Fuschino, F., Marisaldi, M., Giuliani, A., Cutini, S., Feroci, M., Costa, E., Pittori, C., Tavani, M., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Chen, A. W., D'Ammando, F., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Fiorini, M., Galli, M., Gianotti, F., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Antonelli, L. A., Colafrancesco, S., Giommi, P., Santolamazza, P., Verrecchia, F., Lucarelli, F., and Salotti, L.
Abstract: Context. The detection and the characterization of the highenergy emission component from individual gamma-ray bursts (GRBs) is one of the key science objectives of the currently operating gamma-ray satellite AGILE, launched in April 2007. In its first two years of operation AGILE detected three GRBs with photons of energy larger than 30 MeV. One more GRB was detected in AGILE third operation year, while operating in spinning mode. Aims. For the 64 other GRBs localized during the period July 2007 to October 2009 in the field of view of the AGILE Gamma-Ray Imaging Detector (GRID), but not detected by this instrument, we estimate the count and flux upper limits on the GRB high energy emission in the AGILE-GRID energy band (30 MeV-3 GeV). Methods. To calculate the count upper limits, we adopted a Bayesian approach. The flux upper limits are derived using several assumptions on the high-energy spectral behavior. For 28 GRBs with available prompt spectral information, a flux upper limit and the comparison with the expected flux estimated from spectral extrapolation of the Band spectrum to the 30 MeV-3 GeV band are provided. Moreover, upper limits on the flux under the assumption of an extra power law component dominating the 30 MeV-3 GeV band are calculated for all GRBs and considering four different values for the spectral photon index. Finally, we performed a likelihood upper limit on the possible delayed emission up to 1 h after the GRB. Results. The estimated flux upper limits range between 1 × 10 -4 and ∼2 × 10 -2 photons cm -2 s -1 and generally lie above the flux estimated from the extrapolation of the prompt emission in the 30 MeV-3 GeV band. A notable case is GRB 080721, where the AGILE-GRID upper limit suggests a steeper spectral index or the presence of a cut-off in the high energy part of the Band prompt spectrum. The four GRBs detected by AGILE-GRID show high-energy (30 MeV-3 GeV) to low-energy (1 keV-10 MeV) fluence ratios similar to those estimated in this
Published: 2012
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18. Upper limits on the high-energy emission from gamma-ray bursts observed by AGILE-GRID

Author: Longo, F., Moretti, Elena, Nava, L., Desiante, R., Olivo, M., Del Monte, E., Rappoldi, A., Fuschino, F., Marisaldi, M., Giuliani, A., Cutini, S., Feroci, M., Costa, E., Pittori, C., Tavani, M., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Chen, A. W., D'Ammando, F., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Fiorini, M., Galli, M., Gianotti, F., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Antonelli, L. A., Colafrancesco, S., Giommi, P., Santolamazza, P., Verrecchia, F., Lucarelli, F., Salotti, L., Longo, F., Moretti, Elena, Nava, L., Desiante, R., Olivo, M., Del Monte, E., Rappoldi, A., Fuschino, F., Marisaldi, M., Giuliani, A., Cutini, S., Feroci, M., Costa, E., Pittori, C., Tavani, M., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cardillo, M., Cattaneo, P. W., Chen, A. W., D'Ammando, F., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Fiorini, M., Galli, M., Gianotti, F., Giusti, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Vercellone, S., Vittorini, V., Zanello, D., Antonelli, L. A., Colafrancesco, S., Giommi, P., Santolamazza, P., Verrecchia, F., Lucarelli, F., and Salotti, L.
Abstract: Context. The detection and the characterization of the highenergy emission component from individual gamma-ray bursts (GRBs) is one of the key science objectives of the currently operating gamma-ray satellite AGILE, launched in April 2007. In its first two years of operation AGILE detected three GRBs with photons of energy larger than 30 MeV. One more GRB was detected in AGILE third operation year, while operating in spinning mode. Aims. For the 64 other GRBs localized during the period July 2007 to October 2009 in the field of view of the AGILE Gamma-Ray Imaging Detector (GRID), but not detected by this instrument, we estimate the count and flux upper limits on the GRB high energy emission in the AGILE-GRID energy band (30 MeV-3 GeV). Methods. To calculate the count upper limits, we adopted a Bayesian approach. The flux upper limits are derived using several assumptions on the high-energy spectral behavior. For 28 GRBs with available prompt spectral information, a flux upper limit and the comparison with the expected flux estimated from spectral extrapolation of the Band spectrum to the 30 MeV-3 GeV band are provided. Moreover, upper limits on the flux under the assumption of an extra power law component dominating the 30 MeV-3 GeV band are calculated for all GRBs and considering four different values for the spectral photon index. Finally, we performed a likelihood upper limit on the possible delayed emission up to 1 h after the GRB. Results. The estimated flux upper limits range between 1 × 10 -4 and ∼2 × 10 -2 photons cm -2 s -1 and generally lie above the flux estimated from the extrapolation of the prompt emission in the 30 MeV-3 GeV band. A notable case is GRB 080721, where the AGILE-GRID upper limit suggests a steeper spectral index or the presence of a cut-off in the high energy part of the Band prompt spectrum. The four GRBs detected by AGILE-GRID show high-energy (30 MeV-3 GeV) to low-energy (1 keV-10 MeV) fluence ratios similar to those estimated in this, QC 20121212
Published: 2012
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19. The AGILE monitoring of Cygnus X-3: transient gamma-ray emission and spectral constraints

Author: Piano, G., Tavani, M., Vittorini, V., Trois, A., Giuliani, A., Bulgarelli, A., Evangelista, Y., Coppi, P., Del Monte, E., Sabatini, S., Striani, E., Donnarumma, I., Hannikainen, D., Koljonen, K. I. I., McCollough, M., Pooley, G., Trushkin, S., Zanin, R., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Chen, A. W., Colafrancesco, S., Feroci, M., Fuschino, F., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Soffitta, P., Trifoglio, M., Vercellone, S., Verrecchia, F., Piano, G., Tavani, M., Vittorini, V., Trois, A., Giuliani, A., Bulgarelli, A., Evangelista, Y., Coppi, P., Del Monte, E., Sabatini, S., Striani, E., Donnarumma, I., Hannikainen, D., Koljonen, K. I. I., McCollough, M., Pooley, G., Trushkin, S., Zanin, R., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Chen, A. W., Colafrancesco, S., Feroci, M., Fuschino, F., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Soffitta, P., Trifoglio, M., Vercellone, S., and Verrecchia, F.
Abstract: We present the AGILE-GRID monitoring of Cygnus X-3, during the period between November 2007 and July 2009. We report here the whole AGILE-GRID monitoring of Cygnus X-3 in the AGILE "pointing" mode data-taking, to confirm that the gamma-ray activity coincides with the same repetitive pattern of multiwavelength emission and to analyze in depth the overall gamma-ray spectrum by assuming both leptonic and hadronic scenarios. Seven intense gamma-ray events were detected in this period, with a typical event lasting one or two days. These durations are longer than the likely cooling times of the gamma-ray emitting particles, implying we see continuous acceleration rather than the result of an impulsive event such as the ejection of a single plasmoid which then cools as it propagates outwards. Cross-correlating the AGILE-GRID light curve with X-ray and radio monitoring data, we find that the main events of gamma-ray activity have been detected while the system was in soft spectral X-ray states (RXTE/ASM count rate > 3 counts/s), that coincide with local and often sharp minima of the hard X-ray flux (Swift/BAT count rate < 0.02 counts/cm^2/s), a few days before intense radio outbursts. [...] These gamma-ray events may thus reflect a sharp transition in the structure of the accretion disk and its corona, which leads to a rebirth of the microquasar jet and subsequent enhanced radio activity. [...] Finally, we examine leptonic and hadronic emission models for the gamma-ray events and find that both scenarios are valid. In the leptonic model - based on inverse Compton scatterings of mildly relativistic electrons on soft photons from the Wolf-Rayet companion star and from the accretion disk - the emitting particles may also contribute to the overall hard X-ray spectrum, possibly explaining the hard non-thermal power-law tail sometimes seen during special soft X-ray states in Cygnus X-3., Comment: Accepted for publication in A&A on July 26, 2012
Published: 2012
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20. The characterization of the distant blazar GB6 J1239+0443 from flaring and low activity periods

Author: Pacciani, L., Donnarumma, I., Denney, K. D., Assef, R. J., Ikejiri, Y., Yamanaka, M., Uemura, M., Domingo, A., Giommi, P., Tarchi, A., Verrecchia, F., Longo, F., Rainó, S., Giusti, M., Vercellone, S., Chen, A. W., Striani, E., Vittorini, V., Tavani, M., Bulgarelli, A., Giuliani, A., Pucella, G., Argan, A., Barbiellini, G., Caraveo, P., Cattaneo, P. W., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Zanello, D., Pittori, C., Santolamazza, P., Lucarelli, F., Salotti, L., Valentini, G., Pacciani, L., Donnarumma, I., Denney, K. D., Assef, R. J., Ikejiri, Y., Yamanaka, M., Uemura, M., Domingo, A., Giommi, P., Tarchi, A., Verrecchia, F., Longo, F., Rainó, S., Giusti, M., Vercellone, S., Chen, A. W., Striani, E., Vittorini, V., Tavani, M., Bulgarelli, A., Giuliani, A., Pucella, G., Argan, A., Barbiellini, G., Caraveo, P., Cattaneo, P. W., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Zanello, D., Pittori, C., Santolamazza, P., Lucarelli, F., Salotti, L., and Valentini, G.
Abstract: In 2008 AGILE and Fermi detected gamma-ray flaring activity from the unidentified EGRET source 3EG J1236+0457, recently associated with a flat spectrum radio quasar GB6 J1239+0443 at z=1.762. The optical counterpart of the gamma-ray source underwent a flux enhancement of a factor 15-30 in 6 years, and of ~10 in six months. We interpret this flare-up in terms of a transition from an accretion-disk dominated emission to a synchrotron-jet dominated one. We analysed a Sloan Digital Sky Survey (SDSS) archival optical spectrum taken during a period of low radio and optical activity of the source. We estimated the mass of the central black hole using the width of the CIV emission line. In our work, we have also investigated SDSS archival optical photometric data and UV GALEX observations to estimate the thermal-disk emission contribution of GB6 J1239+0443. Our analysis of the gamma-ray data taken during the flaring episodes indicates a flat gamma-ray spectrum, with an extension of up to 15 GeV, with no statistically-relevant sign of absorption from the broad line region, suggesting that the blazar-zone is located beyond the broad line region. This result is confirmed by the modeling of the broad-band spectral energy distribution (well constrained by the available multiwavelength data) of the flaring activity periods and by the accretion disk luminosity and black hole mass estimated by us using archival data., Comment: 30 pages, 7 figures, 4 tables MNRAS Accepted on 2012 June 18
Published: 2012
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21. The AGILE monitoring of Cygnus X-3: transient gamma-ray emission and spectral constraints

Author: Piano, G., Tavani, M., Vittorini, V., Trois, A., Giuliani, A., Bulgarelli, A., Evangelista, Y., Coppi, P., Del Monte, E., Sabatini, S., Striani, E., Donnarumma, I., Hannikainen, D., Koljonen, K. I. I., McCollough, M., Pooley, G., Trushkin, S., Zanin, R., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Chen, A. W., Colafrancesco, S., Feroci, M., Fuschino, F., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Soffitta, P., Trifoglio, M., Vercellone, S., Verrecchia, F., Piano, G., Tavani, M., Vittorini, V., Trois, A., Giuliani, A., Bulgarelli, A., Evangelista, Y., Coppi, P., Del Monte, E., Sabatini, S., Striani, E., Donnarumma, I., Hannikainen, D., Koljonen, K. I. I., McCollough, M., Pooley, G., Trushkin, S., Zanin, R., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Chen, A. W., Colafrancesco, S., Feroci, M., Fuschino, F., Giusti, M., Longo, F., Morselli, A., Pellizzoni, A., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Soffitta, P., Trifoglio, M., Vercellone, S., and Verrecchia, F.
Abstract: We present the AGILE-GRID monitoring of Cygnus X-3, during the period between November 2007 and July 2009. We report here the whole AGILE-GRID monitoring of Cygnus X-3 in the AGILE "pointing" mode data-taking, to confirm that the gamma-ray activity coincides with the same repetitive pattern of multiwavelength emission and to analyze in depth the overall gamma-ray spectrum by assuming both leptonic and hadronic scenarios. Seven intense gamma-ray events were detected in this period, with a typical event lasting one or two days. These durations are longer than the likely cooling times of the gamma-ray emitting particles, implying we see continuous acceleration rather than the result of an impulsive event such as the ejection of a single plasmoid which then cools as it propagates outwards. Cross-correlating the AGILE-GRID light curve with X-ray and radio monitoring data, we find that the main events of gamma-ray activity have been detected while the system was in soft spectral X-ray states (RXTE/ASM count rate > 3 counts/s), that coincide with local and often sharp minima of the hard X-ray flux (Swift/BAT count rate < 0.02 counts/cm^2/s), a few days before intense radio outbursts. [...] These gamma-ray events may thus reflect a sharp transition in the structure of the accretion disk and its corona, which leads to a rebirth of the microquasar jet and subsequent enhanced radio activity. [...] Finally, we examine leptonic and hadronic emission models for the gamma-ray events and find that both scenarios are valid. In the leptonic model - based on inverse Compton scatterings of mildly relativistic electrons on soft photons from the Wolf-Rayet companion star and from the accretion disk - the emitting particles may also contribute to the overall hard X-ray spectrum, possibly explaining the hard non-thermal power-law tail sometimes seen during special soft X-ray states in Cygnus X-3., Comment: Accepted for publication in A&A on July 26, 2012
Published: 2012
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22. The characterization of the distant blazar GB6 J1239+0443 from flaring and low activity periods

Author: Pacciani, L., Donnarumma, I., Denney, K. D., Assef, R. J., Ikejiri, Y., Yamanaka, M., Uemura, M., Domingo, A., Giommi, P., Tarchi, A., Verrecchia, F., Longo, F., Rainó, S., Giusti, M., Vercellone, S., Chen, A. W., Striani, E., Vittorini, V., Tavani, M., Bulgarelli, A., Giuliani, A., Pucella, G., Argan, A., Barbiellini, G., Caraveo, P., Cattaneo, P. W., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Zanello, D., Pittori, C., Santolamazza, P., Lucarelli, F., Salotti, L., Valentini, G., Pacciani, L., Donnarumma, I., Denney, K. D., Assef, R. J., Ikejiri, Y., Yamanaka, M., Uemura, M., Domingo, A., Giommi, P., Tarchi, A., Verrecchia, F., Longo, F., Rainó, S., Giusti, M., Vercellone, S., Chen, A. W., Striani, E., Vittorini, V., Tavani, M., Bulgarelli, A., Giuliani, A., Pucella, G., Argan, A., Barbiellini, G., Caraveo, P., Cattaneo, P. W., Colafrancesco, S., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Zanello, D., Pittori, C., Santolamazza, P., Lucarelli, F., Salotti, L., and Valentini, G.
Abstract: In 2008 AGILE and Fermi detected gamma-ray flaring activity from the unidentified EGRET source 3EG J1236+0457, recently associated with a flat spectrum radio quasar GB6 J1239+0443 at z=1.762. The optical counterpart of the gamma-ray source underwent a flux enhancement of a factor 15-30 in 6 years, and of ~10 in six months. We interpret this flare-up in terms of a transition from an accretion-disk dominated emission to a synchrotron-jet dominated one. We analysed a Sloan Digital Sky Survey (SDSS) archival optical spectrum taken during a period of low radio and optical activity of the source. We estimated the mass of the central black hole using the width of the CIV emission line. In our work, we have also investigated SDSS archival optical photometric data and UV GALEX observations to estimate the thermal-disk emission contribution of GB6 J1239+0443. Our analysis of the gamma-ray data taken during the flaring episodes indicates a flat gamma-ray spectrum, with an extension of up to 15 GeV, with no statistically-relevant sign of absorption from the broad line region, suggesting that the blazar-zone is located beyond the broad line region. This result is confirmed by the modeling of the broad-band spectral energy distribution (well constrained by the available multiwavelength data) of the flaring activity periods and by the accretion disk luminosity and black hole mass estimated by us using archival data., Comment: 30 pages, 7 figures, 4 tables MNRAS Accepted on 2012 June 18
Published: 2012
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23. Variable and transient Galactic gamma-ray sources with AGILE

Author: Longo, F., Bulgarelli, A., Chen, A., Gianotti, F., Giuliani, A., Lucarelli, F., Piano, G., Pittori, C., Sabatini, S., Striani, E., Tavani, M., Trifoglio, M., Verrecchia, F., Argan, A., Barbiellini, G., Costa, E., Caraveo, P., Cattaneo, P. W., D'Ammando, F., De Paris, G., Del Monte, E., DiCocco, G., Di Persio, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Froysland, T., Fuschino, F., Galli, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Moretti, Elena, 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., Antonelli, L. A., Colafrancesco, S., Cutini, S., Giommi, P., Santolamazza, P., Salotti, L., Longo, F., Bulgarelli, A., Chen, A., Gianotti, F., Giuliani, A., Lucarelli, F., Piano, G., Pittori, C., Sabatini, S., Striani, E., Tavani, M., Trifoglio, M., Verrecchia, F., Argan, A., Barbiellini, G., Costa, E., Caraveo, P., Cattaneo, P. W., D'Ammando, F., De Paris, G., Del Monte, E., DiCocco, G., Di Persio, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Froysland, T., Fuschino, F., Galli, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Moretti, Elena, 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., Antonelli, L. A., Colafrancesco, S., Cutini, S., Giommi, P., Santolamazza, P., and Salotti, L.
Abstract: AGILE has been providing continous monitoring of the Galactic plane in its three years of operation. Thanks to its sensitivity at energies near 100 MeV, AGILE has observed variability and transient behaviour in a number of sources. Simultaneous hard-X-ray coverage, rapid alerts to the astronomical community, and multiwavelength campaigns have provided identifications for some of these sources and placed constraints on others. We provide an overview of these observations and their possible counterparts, including microquasars and colliding wind binaries., QC 20140901
Published: 2011
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24. The AGILE observations of the hard and bright GRB 100724B

Author: Del Monte, E., Barbiellini, G., Donnarumma, I., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Pucella, G., Tavani, M., Trifoglio, M., Trois, A., Argan, A., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Costa, E., D'Ammando, F., Di Cocco, G., Evangelista, Y., Feroci, M., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Vallazza, E., Vercellone, S., Vittorini, V., Antonelli, L. A., Cutini, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., Salotti, L., Del Monte, E., Barbiellini, G., Donnarumma, I., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Pucella, G., Tavani, M., Trifoglio, M., Trois, A., Argan, A., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Costa, E., D'Ammando, F., Di Cocco, G., Evangelista, Y., Feroci, M., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Vallazza, E., Vercellone, S., Vittorini, V., Antonelli, L. A., Cutini, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.
Abstract: The observation of Gamma Ray Bursts (GRBs) in the gamma-ray band has been advanced by the AGILE and Fermi satellites after the era of the Compton Gamma-Ray Observatory. AGILE and Fermi are showing that the GeV-bright GRBs share a set of common features, particularly the high fluence from the keV up to the GeV energy bands, the high value of the minimum Lorentz factor, the presence of an extended emission of gamma-rays, often delayed with respect to lower energies, and finally the possible presence of multiple spectral components. GRB 100724B, localised in a joint effort by Fermi and the InterPlanetary Newtork, is the brightest burst detected in gamma-rays so far by AGILE. Characteristic features of GRB 100724B are the simultaneous emissions at MeV and GeV, without delayed onset nor time lag as shown by the analysis of the cross correlation function, and the significant spectral evolution in hard X-rays over the event duration. In this paper we show the analysis of the AGILE data of GRB 100724B and we discuss its features in the context of the bursts observed so far in gamma-rays and the recently proposed models., Comment: 8 pages, 5 figures. Accepted for publication by A&A. Final version after the correction by the language editor
Published: 2011
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25. Characterization of a tagged $\gamma$-ray beam line at the DA$\Phi$NE Beam Test Facility

Author: Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., Salotti, L., Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., and Salotti, L.
Abstract: At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a $\gamma$-ray beam to validate the simulation used to calculate the energy response function and the effective area versus the energy and the direction of the $\gamma$ rays. A tagged $\gamma$-ray beam line was designed at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali of Frascati (LNF), based on an electron beam generating $\gamma$ rays through bremsstrahlung in a position-sensitive target. The $\gamma$-ray energy is deduced by difference with the post-bremsstrahlung electron energy \cite{prest}-\cite{hasan}. The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS system as tagged photon beam requires understanding the efficiency of $\gamma$-ray tagging, the probability of fake tagging, the energy resolution and the relation of the PTS hit position versus the $\gamma$-ray energy. This paper describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation., Comment: 23 pages; 17 figures. Second and final version accepted by Nucl. Instr. & Meth. A
Published: 2011
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26. The observation of Gamma Ray Bursts and Terrestrial Gamma-ray Flashes with AGILE

Author: Del Monte, E., Barbiellini, G., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Mereghetti, S., Moretti, E., Trifoglio, M., Vianello, G., Costa, E., Donnarumma, I., Evangelista, Y., Feroci, M., Galli, M., Lapshov, I., Lazzarotto, F., Lipari, P., Pacciani, L., Rapisarda, M., Soffitta, P., Tavani, M., Vercellone, S., Cutini, S., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Di Cocco, G., Gianotti, F., Labanti, C., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rappoldi, A., Sabatini, S., Striani, E., Trois, A., Vallazza, E., Vittorini, V., Antonelli, L. A., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., Salotti, L., Del Monte, E., Barbiellini, G., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Mereghetti, S., Moretti, E., Trifoglio, M., Vianello, G., Costa, E., Donnarumma, I., Evangelista, Y., Feroci, M., Galli, M., Lapshov, I., Lazzarotto, F., Lipari, P., Pacciani, L., Rapisarda, M., Soffitta, P., Tavani, M., Vercellone, S., Cutini, S., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Di Cocco, G., Gianotti, F., Labanti, C., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rappoldi, A., Sabatini, S., Striani, E., Trois, A., Vallazza, E., Vittorini, V., Antonelli, L. A., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.
Abstract: Since its early phases of operation, the AGILE mission is successfully observing Gamma Ray Bursts (GRBs) in the hard X-ray band with the SuperAGILE imager and in the MeV range with the Mini-Calorimeter. Up to now, three firm GRB detections were obtained above 25 MeV and some bursts were detected with lower statistical confidence in the same energy band. When a GRB is localized, either by SuperAGILE or Swift/BAT or INTEGRAL/IBIS or Fermi/GBM or IPN, inside the field of view of the Gamma Ray Imager of AGILE, a detection is searched for in the gamma ray band or an upper limit is provided. A promising result of AGILE is the detection of very short gamma ray transients, a few ms in duration and possibly identified with Terrestrial Gamma-ray Flashes. In this paper we show the current status of the observation of Gamma Ray Bursts and Terrestrial Gamma-ray Flashes with AGILE., Comment: Four pages and four figures
Published: 2011
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27. First results about on-ground calibration of the Silicon Tracker for the AGILE satellite

Author: AGILE Collaboration, Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., Salotti, L., AGILE Collaboration, Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., and Salotti, L.
Abstract: The AGILE scientific instrument has been calibrated with a tagged $\gamma$-ray beam at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali di Frascati (LNF). The goal of the calibration was the measure of the Point Spread Function (PSF) as a function of the photon energy and incident angle and the validation of the Monte Carlo (MC) simulation of the silicon tracker operation. The calibration setup is described and some preliminary results are presented., Comment: Presented at the 2nd Roma International Conference on Astroparticle Physics 2009, Villa Mondragone, Rome, Italy, May 13-15 2009. Pages 6, Figures 10
Published: 2011
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28. Neutral pion emission from accelerated protons in the supernova remnant W44

Author: Giuliani, A., Cardillo, M., Tavani, M., Fukui, Y., Yoshiike, S., Torii, K., Dubner, G., Castelletti, G., Barbiellini, G., Bulgarelli, A., Caraveo, P., Costa, E., Cattaneo, P. W., Chen, A., Contessi, T., Del Monte, E., Donnarumma, I., Evangelista, Y., Feroci, M., Gianotti, F., Lazzarotto, F., Lucarelli, F., Longo, F., Marisaldi, M., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Picozza, P., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vercellone, S., Verrecchia, F., Vittorini, V., Colafrancesco, S., Giommi, P., Bignami, G., Giuliani, A., Cardillo, M., Tavani, M., Fukui, Y., Yoshiike, S., Torii, K., Dubner, G., Castelletti, G., Barbiellini, G., Bulgarelli, A., Caraveo, P., Costa, E., Cattaneo, P. W., Chen, A., Contessi, T., Del Monte, E., Donnarumma, I., Evangelista, Y., Feroci, M., Gianotti, F., Lazzarotto, F., Lucarelli, F., Longo, F., Marisaldi, M., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Picozza, P., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vercellone, S., Verrecchia, F., Vittorini, V., Colafrancesco, S., Giommi, P., and Bignami, G.
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., Comment: accepted for publication on ApJL
Published: 2011
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29. AGILE detection of Cygnus X-3 {\gamma}-ray active states during the period mid-2009/mid-2010

Author: Bulgarelli, A., Tavani, M., Chen, A. W., Evangelista, Y., Trifoglio, M., Gianotti, F., Piano, G., Sabatini, S., Striani, E., Pooley, G., Trushkin, S., Nizhelskij, N. A., McCollough, M., Koljonen, K. I. I., Hannikainen, D., Lähteenmäki, A., Tammi, J., Lavonen, N., Steeghs, D., Aboudan, A., Argan, A., Barbiellini, G., Campana, R., Caraveo, P., Cattaneo, P. W., Cocco, V., Contessi, T., Costa, E., D'Ammando, 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., Bulgarelli, A., Tavani, M., Chen, A. W., Evangelista, Y., Trifoglio, M., Gianotti, F., Piano, G., Sabatini, S., Striani, E., Pooley, G., Trushkin, S., Nizhelskij, N. A., McCollough, M., Koljonen, K. I. I., Hannikainen, D., Lähteenmäki, A., Tammi, J., Lavonen, N., Steeghs, D., Aboudan, A., Argan, A., Barbiellini, G., Campana, R., Caraveo, P., Cattaneo, P. W., Cocco, V., Contessi, T., Costa, E., D'Ammando, 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., and Salotti, L.
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
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30. The brightest gamma-ray flaring blazar in the sky: AGILE and multi-wavelength observations of 3C 454.3 during November 2010

Author: Vercellone, S., Striani, E., Vittorini, V., Donnarumma, I., Pacciani, L., Pucella, G., Tavani, M., Raiteri, C. M., Villata, M., Romano, P., Fiocchi, M., Bazzano, A., Bianchin, V., Ferrigno, C., Maraschi, L., Pian, E., Türler, M., Ubertini, P., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Del Monte, E., Evangelista, Y., Feroci, M., Ferrari, A., Fuschino, F., Gianotti, F., Giusti, M., Lazzarotto, F., Pellizzoni, A., Piano, G., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Giommi, P., Lucarelli, F., Pittori, C., Santolamazza, P., Verrecchia, F., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Berdyugin, A., Borman, G. A., Chigladze, R., Efimov, Yu. S., Efimova, N. V., Gómez, J. L., Gurwell, M. A., McHardy, I. M., Joshi, M., Kimeridze, G. N., Krajci, T., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lindfors, E., Molina, S. N., Morozova, D. A., Nazarov, S. V., Nikolashvili, M. G., Nilsson, K., Pasanen, M., Reinthal, R., Ros, J. A., Sadun, A. C., Sakamoto, T., Sallum, S., Sergeev, S. G., Schwartz, R. D., Sigua, L. A., Sillanpää, A., Sokolovsky, K. V., Strelnitski, V., Takalo, L., Taylor, B., Walker, G., Vercellone, S., Striani, E., Vittorini, V., Donnarumma, I., Pacciani, L., Pucella, G., Tavani, M., Raiteri, C. M., Villata, M., Romano, P., Fiocchi, M., Bazzano, A., Bianchin, V., Ferrigno, C., Maraschi, L., Pian, E., Türler, M., Ubertini, P., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Del Monte, E., Evangelista, Y., Feroci, M., Ferrari, A., Fuschino, F., Gianotti, F., Giusti, M., Lazzarotto, F., Pellizzoni, A., Piano, G., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Giommi, P., Lucarelli, F., Pittori, C., Santolamazza, P., Verrecchia, F., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Berdyugin, A., Borman, G. A., Chigladze, R., Efimov, Yu. S., Efimova, N. V., Gómez, J. L., Gurwell, M. A., McHardy, I. M., Joshi, M., Kimeridze, G. N., Krajci, T., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lindfors, E., Molina, S. N., Morozova, D. A., Nazarov, S. V., Nikolashvili, M. G., Nilsson, K., Pasanen, M., Reinthal, R., Ros, J. A., Sadun, A. C., Sakamoto, T., Sallum, S., Sergeev, S. G., Schwartz, R. D., Sigua, L. A., Sillanpää, A., Sokolovsky, K. V., Strelnitski, V., Takalo, L., Taylor, B., and Walker, G.
Abstract: Since 2005, the blazar 3C 454.3 has shown remarkable flaring activity at all frequencies, and during the last four years it has exhibited more than one gamma-ray flare per year, becoming the most active gamma-ray blazar in the sky. We present for the first time the multi-wavelength AGILE, SWIFT, INTEGRAL, and GASP-WEBT data collected in order to explain the extraordinary gamma-ray flare of 3C 454.3 which occurred in November 2010. On 2010 November 20 (MJD 55520), 3C 454.3 reached a peak flux (E>100 MeV) of F_gamma(p) = (6.8+-1.0)E-5 ph/cm2/s on a time scale of about 12 hours, more than a factor of 6 higher than the flux of the brightest steady gamma-ray source, the Vela pulsar, and more than a factor of 3 brighter than its previous super-flare on 2009 December 2-3. The multi-wavelength data make a thorough study of the present event possible: the comparison with the previous outbursts indicates a close similarity to the one that occurred in 2009. By comparing the broadband emission before, during, and after the gamma-ray flare, we find that the radio, optical and X-ray emission varies within a factor 2-3, whereas the gamma-ray flux by a factor of 10. This remarkable behavior is modeled by an external Compton component driven by a substantial local enhancement of soft seed photons., Comment: Accepted for publication in ApJ Letters. 18 Pages, 4 Figures, 1 Table
Published: 2011
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31. The remarkable gamma-ray activity in the gravitationally lensed blazar PKS 1830-211

Author: Donnarumma, I., De Rosa, A., Vittorini, V., Miller, H. R., Popovic, L. C., Simic, S., Tavani, M., Eggen, J., Maune, J., Kuulkers, E., Striani, E., Vercellone, S., Pucella, G., Verrecchia, F., Pittori, C., Giommi, P., Pacciani, L., Barbiellini, G., Bulgarelli, A., Cattaneo, P. W., Chen, A. W., Costa, E., Del Monte, E., Evangelista, Y., Feroci, M., Fuschino, F., Gianotti, F., Giuliani, A., Giusti, M., Lazzarotto, F., Longo, F., Lucarelli, F., Pellizzoni, A., Piano, G., Soffitta, P., Trifoglio, M., Trois, A., Donnarumma, I., De Rosa, A., Vittorini, V., Miller, H. R., Popovic, L. C., Simic, S., Tavani, M., Eggen, J., Maune, J., Kuulkers, E., Striani, E., Vercellone, S., Pucella, G., Verrecchia, F., Pittori, C., Giommi, P., Pacciani, L., Barbiellini, G., Bulgarelli, A., Cattaneo, P. W., Chen, A. W., Costa, E., Del Monte, E., Evangelista, Y., Feroci, M., Fuschino, F., Gianotti, F., Giuliani, A., Giusti, M., Lazzarotto, F., Longo, F., Lucarelli, F., Pellizzoni, A., Piano, G., Soffitta, P., Trifoglio, M., and Trois, A.
Abstract: We report the extraordinary gamma-ray activity (E>100 MeV) of the gravitationally lensed blazar PKS 1830-211 (z=2.507) detected by AGILE between October and November 2010. The source experienced on October 14 a flux increase of a factor of ~ 12 with respect to its average value and kept brightest at this flux level (~ 500 x 10^{-8} ph cm^-2 sec^-1) for about 4 days. The 1-month gamma-ray light curve across the flare showed a mean flux F(E>100 MeV)= 200 x 10^{-8} ph cm^-2 sec^-1, which resulted in an enhancement by a factor of 4 with respect to the average value. Following the gamma-ray flare, the source was observed in NIR-Optical energy bands at the Cerro Tololo Inter-American Observatory and in X-rays by Swift/XRT and INTEGRAL/IBIS. The main result of these multifrequency observations is that the large variability observed in gamma-rays has not a significant counterpart at lower frequencies: no variation greater than a factor of ~ 1.5 resulted in NIR and X-ray energy bands. PKS 1830-211 is then a good "gamma-ray only flaring" blazar showing substantial variability only above 10-100 MeV. We discuss the theoretical implications of our findings., Comment: 7 pages, 2 figures, 1 table, accepted for publication in ApJL
Published: 2011
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32. The Crab Nebula super-flare in April 2011: extremely fast particle acceleration and gamma-ray emission

Author: Striani, E., Tavani, M., Piano, G., Donnarumma, I., Pucella, G., Vittorini, V., Bulgarelli, A., Trois, A., Pittori, C., Verrecchia, F., Costa, E., Weisskopf, M., Tennant, A., Argan, A., Barbiellini, G., Caraveo, P., Cardillo, M, Cattaneo, P. W., Chen, A. W., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Picozza, P., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Vercellone, S., Lucarelli, F., Santolamazza, P., Giommi, P., Striani, E., Tavani, M., Piano, G., Donnarumma, I., Pucella, G., Vittorini, V., Bulgarelli, A., Trois, A., Pittori, C., Verrecchia, F., Costa, E., Weisskopf, M., Tennant, A., Argan, A., Barbiellini, G., Caraveo, P., Cardillo, M, Cattaneo, P. W., Chen, A. W., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Picozza, P., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Vercellone, S., Lucarelli, F., Santolamazza, P., and Giommi, P.
Abstract: We report on the extremely intense and fast gamma-ray are above 100 MeV detected by AGILE from the Crab Nebula in mid-April 2011. This event is the fourth of a sequence of reported major gamma-ray flares produced by the Crab Nebula in the period 2007/mid-2011. These events are attributed to strong radiative and plasma instabilities in the inner Crab Nebula, and their properties are crucial for theoretical studies of fast and efficient particle acceleration up to 10^15 eV. Here we study the very rapid flux and spectral evolution of the event that reached on April 16, 2011 the record-high peak flux of F = (26 +/- 5) x 10^-6 ph cm^-2 s^-1 with a risetime timescale that we determine to be in the range 6-10 hrs. The peak flaring gamma-ray spectrum reaches a distinct maximum near 500 MeV with no substantial emission above 1 GeV. The very rapid risetime and overall evolution of the Crab Nebula are strongly constrain the acceleration mechanisms and challenge MHD models. We briefly discuss the theoretical implications of our observations., Comment: 4 pages, 2 figures. Accepted for pubblication in ApJL
Published: 2011
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33. Discovery of Powerful Gamma-Ray Flares from the Crab Nebula

Author: Tavani, M., Bulgarelli, A., Vittorini, V., Pellizzoni, A., Striani, E., Caraveo, P., Weisskopf, M. C., 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, C. O., Trifoglio, M., Gianotti, F., Vercellone, S., Argan, A., Barbiellini, G., Cattaneo, P. W., Chen, A. W., Contessi, T., D'Ammando, F., DeParis, 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., Bignami, G. F., Tavani, M., Bulgarelli, A., Vittorini, V., Pellizzoni, A., Striani, E., Caraveo, P., Weisskopf, M. C., 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, C. O., Trifoglio, M., Gianotti, F., Vercellone, S., Argan, A., Barbiellini, G., Cattaneo, P. W., Chen, A. W., Contessi, T., D'Ammando, F., DeParis, 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, G. F.
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 MeV-10 GeV) flares observed by the AGILE satellite in September, 2010 and October, 2007. In both cases, the unpulsed flux increased by a factor of 3 compared to the non-flaring flux. The flare luminosity and short timescale favor an origin near the pulsar, and we discuss Chandra Observatory X-ray and HST 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 a ~1-day timescale., Comment: 23 pages (including Supporting On-line Material), 8 figures, 1 table. Version published in Science Express on January 6, 2011 (available at http://www.sciencemag.org/content/early/2011/01/05/science.1200083)
Published: 2011
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34. AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis

Author: D'Ammando, F., Raiteri, C. M., Villata, M., Romano, P., Pucella, G., Krimm, H. A., Covino, S., Orienti, M., Giovannini, G., Vercellone, S., Pian, E., Donnarumma, I., Vittorini, V., Tavani, M., Argan, A., Barbiellini, G., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A. W., Cocco, V., 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., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Benitez, E., Berdyugin, A., Blinov, D. A., Buemi, C. S., Chen, W. P., Di Paola, A., Dolci, M., Forne, E., Fuhrmann, L., Gomez, J. L., Gurwell, M. A., Jordan, B., Jorstad, S. G., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lahteenmaki, A., Leto, P., Lindfors, E., Marscher, A. P., McBreen, B., McHardy, I. M., Morozova, D. A., Nilsson, K., Pasanen, M., Roca-Sogorb, M., Sillanpaa, A., Takalo, L. O., Tornikoski, M., Trigilio, C., Troitsky, I. S., Umana, G., Antonelli, L. A., Colafrancesco, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., Salotti, L., D'Ammando, F., Raiteri, C. M., Villata, M., Romano, P., Pucella, G., Krimm, H. A., Covino, S., Orienti, M., Giovannini, G., Vercellone, S., Pian, E., Donnarumma, I., Vittorini, V., Tavani, M., Argan, A., Barbiellini, G., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A. W., Cocco, V., 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., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Benitez, E., Berdyugin, A., Blinov, D. A., Buemi, C. S., Chen, W. P., Di Paola, A., Dolci, M., Forne, E., Fuhrmann, L., Gomez, J. L., Gurwell, M. A., Jordan, B., Jorstad, S. G., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lahteenmaki, A., Leto, P., Lindfors, E., Marscher, A. P., McBreen, B., McHardy, I. M., Morozova, D. A., Nilsson, K., Pasanen, M., Roca-Sogorb, M., Sillanpaa, A., Takalo, L. O., Tornikoski, M., Trigilio, C., Troitsky, I. S., Umana, G., Antonelli, L. A., Colafrancesco, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.
Abstract: We report on the extreme gamma-ray activity from the FSRQ PKS 1510-089 observed by AGILE in March 2009. In the same period a radio-to-optical monitoring of the source was provided by the GASP-WEBT and REM. Moreover, several Swift ToO observations were triggered, adding important information on the source behaviour from optical/UV to hard X-rays. We paid particular attention to the calibration of the Swift/UVOT data to make it suitable to the blazars spectra. Simultaneous observations from radio to gamma rays allowed us to study in detail the correlation among the emission variability at different frequencies and to investigate the mechanisms at work. In the period 9-30 March 2009, AGILE detected an average gamma-ray flux of (311+/-21)x10^-8 ph cm^-2 s^-1 for E>100 MeV, and a peak level of (702+/-131)x10^-8 ph cm^-2 s^-1 on daily integration. The gamma-ray activity occurred during a period of increasing activity from near-IR to UV, with a flaring episode detected on 26-27 March 2009, suggesting that a single mechanism is responsible for the flux enhancement observed from near-IR to UV. By contrast, Swift/XRT observations seem to show no clear correlation of the X-ray fluxes with the optical and gamma-ray ones. However, the X-ray observations show a harder photon index (1.3-1.6) with respect to most FSRQs and a hint of harder-when-brighter behaviour, indicating the possible presence of a second emission component at soft X-ray energies. Moreover, the broad band spectrum from radio-to-UV confirmed the evidence of thermal features in the optical/UV spectrum of PKS 1510-089 also during high gamma-ray state. On the other hand, during 25-26 March 2009 a flat spectrum in the optical/UV energy band was observed, suggesting an important contribution of the synchrotron emission in this part of the spectrum during the brightest gamma-ray flare, therefore a significant shift of the synchrotron peak., Comment: 13 pages, 7 figures, 3 tables. Accepted for publication in Astronomy and Astrophysics
Published: 2011
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35. Gamma-ray blazars: the view from AGILE

Author: D'Ammando, F., Bulgarelli, A., Chen, A. W., Donnarumma, I., Giuliani, A., Longo, F., Pacciani, L., Pucella, G., Striani, E., Tavani, M., Vercellone, S., Vittorini, V., Covino, S., Krimm, H. A., Raiteri, C. M., Romano, P., Villata, M., D'Ammando, F., Bulgarelli, A., Chen, A. W., Donnarumma, I., Giuliani, A., Longo, F., Pacciani, L., Pucella, G., Striani, E., Tavani, M., Vercellone, S., Vittorini, V., Covino, S., Krimm, H. A., Raiteri, C. M., Romano, P., and Villata, M.
Abstract: During the first 3 years of operation the Gamma-Ray Imaging Detector onboard the AGILE satellite detected several blazars in a high gamma-ray activity: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae, Mrk 421, PKS 0537-441 and 4C +21.35. Thanks to the rapid dissemination of our alerts, we were able to obtain multiwavelength data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, and ARGO as well as radio-to-optical coverage by means of the GASP Project of the WEBT and the REM Telescope. This large multifrequency coverage gave us the opportunity to study the variability correlations between the emission at different frequencies and to obtain simultaneous spectral energy distributions of these sources from radio to gamma-ray energy bands, investigating the different mechanisms responsible for their emission and uncovering in some cases a more complex behaviour with respect to the standard models. We present a review of the most interesting AGILE results on these gamma-ray blazars and their multifrequency data., Comment: 25 pages, 10 figures, accepted for publication on Advances in Space Research. Talk presented at the 38th COSPAR Scientific Assembly (Bremen, Germany; July 18-25, 2010)
Published: 2011
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36. The observation of Gamma Ray Bursts and Terrestrial Gamma-ray Flashes with AGILE

Author: Del Monte, E., Barbiellini, G., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Mereghetti, S., Moretti, E., Trifoglio, M., Vianello, G., Costa, E., Donnarumma, I., Evangelista, Y., Feroci, M., Galli, M., Lapshov, I., Lazzarotto, F., Lipari, P., Pacciani, L., Rapisarda, M., Soffitta, P., Tavani, M., Vercellone, S., Cutini, S., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Di Cocco, G., Gianotti, F., Labanti, C., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rappoldi, A., Sabatini, S., Striani, E., Trois, A., Vallazza, E., Vittorini, V., Antonelli, L. A., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., Salotti, L., Del Monte, E., Barbiellini, G., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Mereghetti, S., Moretti, E., Trifoglio, M., Vianello, G., Costa, E., Donnarumma, I., Evangelista, Y., Feroci, M., Galli, M., Lapshov, I., Lazzarotto, F., Lipari, P., Pacciani, L., Rapisarda, M., Soffitta, P., Tavani, M., Vercellone, S., Cutini, S., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Di Cocco, G., Gianotti, F., Labanti, C., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Pucella, G., Rappoldi, A., Sabatini, S., Striani, E., Trois, A., Vallazza, E., Vittorini, V., Antonelli, L. A., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.
Abstract: Since its early phases of operation, the AGILE mission is successfully observing Gamma Ray Bursts (GRBs) in the hard X-ray band with the SuperAGILE imager and in the MeV range with the Mini-Calorimeter. Up to now, three firm GRB detections were obtained above 25 MeV and some bursts were detected with lower statistical confidence in the same energy band. When a GRB is localized, either by SuperAGILE or Swift/BAT or INTEGRAL/IBIS or Fermi/GBM or IPN, inside the field of view of the Gamma Ray Imager of AGILE, a detection is searched for in the gamma ray band or an upper limit is provided. A promising result of AGILE is the detection of very short gamma ray transients, a few ms in duration and possibly identified with Terrestrial Gamma-ray Flashes. In this paper we show the current status of the observation of Gamma Ray Bursts and Terrestrial Gamma-ray Flashes with AGILE., Comment: Four pages and four figures
Published: 2011
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37. First results about on-ground calibration of the Silicon Tracker for the AGILE satellite

Author: AGILE Collaboration, Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., Salotti, L., AGILE Collaboration, Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., and Salotti, L.
Abstract: The AGILE scientific instrument has been calibrated with a tagged $\gamma$-ray beam at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali di Frascati (LNF). The goal of the calibration was the measure of the Point Spread Function (PSF) as a function of the photon energy and incident angle and the validation of the Monte Carlo (MC) simulation of the silicon tracker operation. The calibration setup is described and some preliminary results are presented., Comment: Presented at the 2nd Roma International Conference on Astroparticle Physics 2009, Villa Mondragone, Rome, Italy, May 13-15 2009. Pages 6, Figures 10
Published: 2011
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38. Characterization of a tagged $\gamma$-ray beam line at the DA$\Phi$NE Beam Test Facility

Author: Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., Salotti, L., Cattaneo, P. W., Argan, A., Boffelli, F., Bulgarelli, A., Buonomo, B., Chen, A. W., D'Ammando, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Longo, F., Marisaldi, M., Mazzitelli, G., Pellizzoni, A., Prest, M., Pucella, G., Quintieri, L., Rappoldi, A., Tavani, M., Trifoglio, M., Trois, A., Valente, P., Vallazza, E., Vercellone, S., Zambra, A., Barbiellini, G., Caraveo, P., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Feroci, M., Ferrari, A., Fiorini, M., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mastropietro, M., Mereghetti, S., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Rapisarda, M., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Vittorini, V., Zanello, D., Colafrancesco, S., Giommi, P., Pittori, C., Santolamazza, P., Verrecchia, F., and Salotti, L.
Abstract: At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a $\gamma$-ray beam to validate the simulation used to calculate the energy response function and the effective area versus the energy and the direction of the $\gamma$ rays. A tagged $\gamma$-ray beam line was designed at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali of Frascati (LNF), based on an electron beam generating $\gamma$ rays through bremsstrahlung in a position-sensitive target. The $\gamma$-ray energy is deduced by difference with the post-bremsstrahlung electron energy \cite{prest}-\cite{hasan}. The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS system as tagged photon beam requires understanding the efficiency of $\gamma$-ray tagging, the probability of fake tagging, the energy resolution and the relation of the PTS hit position versus the $\gamma$-ray energy. This paper describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation., Comment: 23 pages; 17 figures. Second and final version accepted by Nucl. Instr. & Meth. A
Published: 2011
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39. Neutral pion emission from accelerated protons in the supernova remnant W44

Author: Giuliani, A., Cardillo, M., Tavani, M., Fukui, Y., Yoshiike, S., Torii, K., Dubner, G., Castelletti, G., Barbiellini, G., Bulgarelli, A., Caraveo, P., Costa, E., Cattaneo, P. W., Chen, A., Contessi, T., Del Monte, E., Donnarumma, I., Evangelista, Y., Feroci, M., Gianotti, F., Lazzarotto, F., Lucarelli, F., Longo, F., Marisaldi, M., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Picozza, P., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vercellone, S., Verrecchia, F., Vittorini, V., Colafrancesco, S., Giommi, P., Bignami, G., Giuliani, A., Cardillo, M., Tavani, M., Fukui, Y., Yoshiike, S., Torii, K., Dubner, G., Castelletti, G., Barbiellini, G., Bulgarelli, A., Caraveo, P., Costa, E., Cattaneo, P. W., Chen, A., Contessi, T., Del Monte, E., Donnarumma, I., Evangelista, Y., Feroci, M., Gianotti, F., Lazzarotto, F., Lucarelli, F., Longo, F., Marisaldi, M., Mereghetti, S., Pacciani, L., Pellizzoni, A., Piano, G., Picozza, P., Pittori, C., Pucella, G., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vercellone, S., Verrecchia, F., Vittorini, V., Colafrancesco, S., Giommi, P., and Bignami, G.
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., Comment: accepted for publication on ApJL
Published: 2011
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40. AGILE detection of Cygnus X-3 {\gamma}-ray active states during the period mid-2009/mid-2010

Author: Bulgarelli, A., Tavani, M., Chen, A. W., Evangelista, Y., Trifoglio, M., Gianotti, F., Piano, G., Sabatini, S., Striani, E., Pooley, G., Trushkin, S., Nizhelskij, N. A., McCollough, M., Koljonen, K. I. I., Hannikainen, D., Lähteenmäki, A., Tammi, J., Lavonen, N., Steeghs, D., Aboudan, A., Argan, A., Barbiellini, G., Campana, R., Caraveo, P., Cattaneo, P. W., Cocco, V., Contessi, T., Costa, E., D'Ammando, 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., Bulgarelli, A., Tavani, M., Chen, A. W., Evangelista, Y., Trifoglio, M., Gianotti, F., Piano, G., Sabatini, S., Striani, E., Pooley, G., Trushkin, S., Nizhelskij, N. A., McCollough, M., Koljonen, K. I. I., Hannikainen, D., Lähteenmäki, A., Tammi, J., Lavonen, N., Steeghs, D., Aboudan, A., Argan, A., Barbiellini, G., Campana, R., Caraveo, P., Cattaneo, P. W., Cocco, V., Contessi, T., Costa, E., D'Ammando, 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., and Salotti, L.
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
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41. The AGILE observations of the hard and bright GRB 100724B

Author: Del Monte, E., Barbiellini, G., Donnarumma, I., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Pucella, G., Tavani, M., Trifoglio, M., Trois, A., Argan, A., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Costa, E., D'Ammando, F., Di Cocco, G., Evangelista, Y., Feroci, M., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Vallazza, E., Vercellone, S., Vittorini, V., Antonelli, L. A., Cutini, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., Salotti, L., Del Monte, E., Barbiellini, G., Donnarumma, I., Fuschino, F., Giuliani, A., Longo, F., Marisaldi, M., Pucella, G., Tavani, M., Trifoglio, M., Trois, A., Argan, A., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Costa, E., D'Ammando, F., Di Cocco, G., Evangelista, Y., Feroci, M., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Vallazza, E., Vercellone, S., Vittorini, V., Antonelli, L. A., Cutini, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.
Abstract: The observation of Gamma Ray Bursts (GRBs) in the gamma-ray band has been advanced by the AGILE and Fermi satellites after the era of the Compton Gamma-Ray Observatory. AGILE and Fermi are showing that the GeV-bright GRBs share a set of common features, particularly the high fluence from the keV up to the GeV energy bands, the high value of the minimum Lorentz factor, the presence of an extended emission of gamma-rays, often delayed with respect to lower energies, and finally the possible presence of multiple spectral components. GRB 100724B, localised in a joint effort by Fermi and the InterPlanetary Newtork, is the brightest burst detected in gamma-rays so far by AGILE. Characteristic features of GRB 100724B are the simultaneous emissions at MeV and GeV, without delayed onset nor time lag as shown by the analysis of the cross correlation function, and the significant spectral evolution in hard X-rays over the event duration. In this paper we show the analysis of the AGILE data of GRB 100724B and we discuss its features in the context of the bursts observed so far in gamma-rays and the recently proposed models., Comment: 8 pages, 5 figures. Accepted for publication by A&A. Final version after the correction by the language editor
Published: 2011
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42. The brightest gamma-ray flaring blazar in the sky: AGILE and multi-wavelength observations of 3C 454.3 during November 2010

Author: Vercellone, S., Striani, E., Vittorini, V., Donnarumma, I., Pacciani, L., Pucella, G., Tavani, M., Raiteri, C. M., Villata, M., Romano, P., Fiocchi, M., Bazzano, A., Bianchin, V., Ferrigno, C., Maraschi, L., Pian, E., Türler, M., Ubertini, P., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Del Monte, E., Evangelista, Y., Feroci, M., Ferrari, A., Fuschino, F., Gianotti, F., Giusti, M., Lazzarotto, F., Pellizzoni, A., Piano, G., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Giommi, P., Lucarelli, F., Pittori, C., Santolamazza, P., Verrecchia, F., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Berdyugin, A., Borman, G. A., Chigladze, R., Efimov, Yu. S., Efimova, N. V., Gómez, J. L., Gurwell, M. A., McHardy, I. M., Joshi, M., Kimeridze, G. N., Krajci, T., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lindfors, E., Molina, S. N., Morozova, D. A., Nazarov, S. V., Nikolashvili, M. G., Nilsson, K., Pasanen, M., Reinthal, R., Ros, J. A., Sadun, A. C., Sakamoto, T., Sallum, S., Sergeev, S. G., Schwartz, R. D., Sigua, L. A., Sillanpää, A., Sokolovsky, K. V., Strelnitski, V., Takalo, L., Taylor, B., Walker, G., Vercellone, S., Striani, E., Vittorini, V., Donnarumma, I., Pacciani, L., Pucella, G., Tavani, M., Raiteri, C. M., Villata, M., Romano, P., Fiocchi, M., Bazzano, A., Bianchin, V., Ferrigno, C., Maraschi, L., Pian, E., Türler, M., Ubertini, P., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Barbiellini, G., Cardillo, M., Cattaneo, P. W., Del Monte, E., Evangelista, Y., Feroci, M., Ferrari, A., Fuschino, F., Gianotti, F., Giusti, M., Lazzarotto, F., Pellizzoni, A., Piano, G., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Giommi, P., Lucarelli, F., Pittori, C., Santolamazza, P., Verrecchia, F., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Berdyugin, A., Borman, G. A., Chigladze, R., Efimov, Yu. S., Efimova, N. V., Gómez, J. L., Gurwell, M. A., McHardy, I. M., Joshi, M., Kimeridze, G. N., Krajci, T., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lindfors, E., Molina, S. N., Morozova, D. A., Nazarov, S. V., Nikolashvili, M. G., Nilsson, K., Pasanen, M., Reinthal, R., Ros, J. A., Sadun, A. C., Sakamoto, T., Sallum, S., Sergeev, S. G., Schwartz, R. D., Sigua, L. A., Sillanpää, A., Sokolovsky, K. V., Strelnitski, V., Takalo, L., Taylor, B., and Walker, G.
Abstract: Since 2005, the blazar 3C 454.3 has shown remarkable flaring activity at all frequencies, and during the last four years it has exhibited more than one gamma-ray flare per year, becoming the most active gamma-ray blazar in the sky. We present for the first time the multi-wavelength AGILE, SWIFT, INTEGRAL, and GASP-WEBT data collected in order to explain the extraordinary gamma-ray flare of 3C 454.3 which occurred in November 2010. On 2010 November 20 (MJD 55520), 3C 454.3 reached a peak flux (E>100 MeV) of F_gamma(p) = (6.8+-1.0)E-5 ph/cm2/s on a time scale of about 12 hours, more than a factor of 6 higher than the flux of the brightest steady gamma-ray source, the Vela pulsar, and more than a factor of 3 brighter than its previous super-flare on 2009 December 2-3. The multi-wavelength data make a thorough study of the present event possible: the comparison with the previous outbursts indicates a close similarity to the one that occurred in 2009. By comparing the broadband emission before, during, and after the gamma-ray flare, we find that the radio, optical and X-ray emission varies within a factor 2-3, whereas the gamma-ray flux by a factor of 10. This remarkable behavior is modeled by an external Compton component driven by a substantial local enhancement of soft seed photons., Comment: Accepted for publication in ApJ Letters. 18 Pages, 4 Figures, 1 Table
Published: 2011
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43. The remarkable gamma-ray activity in the gravitationally lensed blazar PKS 1830-211

Author: Donnarumma, I., De Rosa, A., Vittorini, V., Miller, H. R., Popovic, L. C., Simic, S., Tavani, M., Eggen, J., Maune, J., Kuulkers, E., Striani, E., Vercellone, S., Pucella, G., Verrecchia, F., Pittori, C., Giommi, P., Pacciani, L., Barbiellini, G., Bulgarelli, A., Cattaneo, P. W., Chen, A. W., Costa, E., Del Monte, E., Evangelista, Y., Feroci, M., Fuschino, F., Gianotti, F., Giuliani, A., Giusti, M., Lazzarotto, F., Longo, F., Lucarelli, F., Pellizzoni, A., Piano, G., Soffitta, P., Trifoglio, M., Trois, A., Donnarumma, I., De Rosa, A., Vittorini, V., Miller, H. R., Popovic, L. C., Simic, S., Tavani, M., Eggen, J., Maune, J., Kuulkers, E., Striani, E., Vercellone, S., Pucella, G., Verrecchia, F., Pittori, C., Giommi, P., Pacciani, L., Barbiellini, G., Bulgarelli, A., Cattaneo, P. W., Chen, A. W., Costa, E., Del Monte, E., Evangelista, Y., Feroci, M., Fuschino, F., Gianotti, F., Giuliani, A., Giusti, M., Lazzarotto, F., Longo, F., Lucarelli, F., Pellizzoni, A., Piano, G., Soffitta, P., Trifoglio, M., and Trois, A.
Abstract: We report the extraordinary gamma-ray activity (E>100 MeV) of the gravitationally lensed blazar PKS 1830-211 (z=2.507) detected by AGILE between October and November 2010. The source experienced on October 14 a flux increase of a factor of ~ 12 with respect to its average value and kept brightest at this flux level (~ 500 x 10^{-8} ph cm^-2 sec^-1) for about 4 days. The 1-month gamma-ray light curve across the flare showed a mean flux F(E>100 MeV)= 200 x 10^{-8} ph cm^-2 sec^-1, which resulted in an enhancement by a factor of 4 with respect to the average value. Following the gamma-ray flare, the source was observed in NIR-Optical energy bands at the Cerro Tololo Inter-American Observatory and in X-rays by Swift/XRT and INTEGRAL/IBIS. The main result of these multifrequency observations is that the large variability observed in gamma-rays has not a significant counterpart at lower frequencies: no variation greater than a factor of ~ 1.5 resulted in NIR and X-ray energy bands. PKS 1830-211 is then a good "gamma-ray only flaring" blazar showing substantial variability only above 10-100 MeV. We discuss the theoretical implications of our findings., Comment: 7 pages, 2 figures, 1 table, accepted for publication in ApJL
Published: 2011
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44. The Crab Nebula super-flare in April 2011: extremely fast particle acceleration and gamma-ray emission

Author: Striani, E., Tavani, M., Piano, G., Donnarumma, I., Pucella, G., Vittorini, V., Bulgarelli, A., Trois, A., Pittori, C., Verrecchia, F., Costa, E., Weisskopf, M., Tennant, A., Argan, A., Barbiellini, G., Caraveo, P., Cardillo, M, Cattaneo, P. W., Chen, A. W., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Picozza, P., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Vercellone, S., Lucarelli, F., Santolamazza, P., Giommi, P., Striani, E., Tavani, M., Piano, G., Donnarumma, I., Pucella, G., Vittorini, V., Bulgarelli, A., Trois, A., Pittori, C., Verrecchia, F., Costa, E., Weisskopf, M., Tennant, A., Argan, A., Barbiellini, G., Caraveo, P., Cardillo, M, Cattaneo, P. W., Chen, A. W., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Picozza, P., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Vercellone, S., Lucarelli, F., Santolamazza, P., and Giommi, P.
Abstract: We report on the extremely intense and fast gamma-ray are above 100 MeV detected by AGILE from the Crab Nebula in mid-April 2011. This event is the fourth of a sequence of reported major gamma-ray flares produced by the Crab Nebula in the period 2007/mid-2011. These events are attributed to strong radiative and plasma instabilities in the inner Crab Nebula, and their properties are crucial for theoretical studies of fast and efficient particle acceleration up to 10^15 eV. Here we study the very rapid flux and spectral evolution of the event that reached on April 16, 2011 the record-high peak flux of F = (26 +/- 5) x 10^-6 ph cm^-2 s^-1 with a risetime timescale that we determine to be in the range 6-10 hrs. The peak flaring gamma-ray spectrum reaches a distinct maximum near 500 MeV with no substantial emission above 1 GeV. The very rapid risetime and overall evolution of the Crab Nebula are strongly constrain the acceleration mechanisms and challenge MHD models. We briefly discuss the theoretical implications of our observations., Comment: 4 pages, 2 figures. Accepted for pubblication in ApJL
Published: 2011
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45. AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis

Author: D'Ammando, F., Raiteri, C. M., Villata, M., Romano, P., Pucella, G., Krimm, H. A., Covino, S., Orienti, M., Giovannini, G., Vercellone, S., Pian, E., Donnarumma, I., Vittorini, V., Tavani, M., Argan, A., Barbiellini, G., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A. W., Cocco, V., 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., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Benitez, E., Berdyugin, A., Blinov, D. A., Buemi, C. S., Chen, W. P., Di Paola, A., Dolci, M., Forne, E., Fuhrmann, L., Gomez, J. L., Gurwell, M. A., Jordan, B., Jorstad, S. G., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lahteenmaki, A., Leto, P., Lindfors, E., Marscher, A. P., McBreen, B., McHardy, I. M., Morozova, D. A., Nilsson, K., Pasanen, M., Roca-Sogorb, M., Sillanpaa, A., Takalo, L. O., Tornikoski, M., Trigilio, C., Troitsky, I. S., Umana, G., Antonelli, L. A., Colafrancesco, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., Salotti, L., D'Ammando, F., Raiteri, C. M., Villata, M., Romano, P., Pucella, G., Krimm, H. A., Covino, S., Orienti, M., Giovannini, G., Vercellone, S., Pian, E., Donnarumma, I., Vittorini, V., Tavani, M., Argan, A., Barbiellini, G., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A. W., Cocco, V., 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., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Benitez, E., Berdyugin, A., Blinov, D. A., Buemi, C. S., Chen, W. P., Di Paola, A., Dolci, M., Forne, E., Fuhrmann, L., Gomez, J. L., Gurwell, M. A., Jordan, B., Jorstad, S. G., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Lahteenmaki, A., Leto, P., Lindfors, E., Marscher, A. P., McBreen, B., McHardy, I. M., Morozova, D. A., Nilsson, K., Pasanen, M., Roca-Sogorb, M., Sillanpaa, A., Takalo, L. O., Tornikoski, M., Trigilio, C., Troitsky, I. S., Umana, G., Antonelli, L. A., Colafrancesco, S., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.
Abstract: We report on the extreme gamma-ray activity from the FSRQ PKS 1510-089 observed by AGILE in March 2009. In the same period a radio-to-optical monitoring of the source was provided by the GASP-WEBT and REM. Moreover, several Swift ToO observations were triggered, adding important information on the source behaviour from optical/UV to hard X-rays. We paid particular attention to the calibration of the Swift/UVOT data to make it suitable to the blazars spectra. Simultaneous observations from radio to gamma rays allowed us to study in detail the correlation among the emission variability at different frequencies and to investigate the mechanisms at work. In the period 9-30 March 2009, AGILE detected an average gamma-ray flux of (311+/-21)x10^-8 ph cm^-2 s^-1 for E>100 MeV, and a peak level of (702+/-131)x10^-8 ph cm^-2 s^-1 on daily integration. The gamma-ray activity occurred during a period of increasing activity from near-IR to UV, with a flaring episode detected on 26-27 March 2009, suggesting that a single mechanism is responsible for the flux enhancement observed from near-IR to UV. By contrast, Swift/XRT observations seem to show no clear correlation of the X-ray fluxes with the optical and gamma-ray ones. However, the X-ray observations show a harder photon index (1.3-1.6) with respect to most FSRQs and a hint of harder-when-brighter behaviour, indicating the possible presence of a second emission component at soft X-ray energies. Moreover, the broad band spectrum from radio-to-UV confirmed the evidence of thermal features in the optical/UV spectrum of PKS 1510-089 also during high gamma-ray state. On the other hand, during 25-26 March 2009 a flat spectrum in the optical/UV energy band was observed, suggesting an important contribution of the synchrotron emission in this part of the spectrum during the brightest gamma-ray flare, therefore a significant shift of the synchrotron peak., Comment: 13 pages, 7 figures, 3 tables. Accepted for publication in Astronomy and Astrophysics
Published: 2011
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46. Gamma-ray blazars: the view from AGILE

Author: D'Ammando, F., Bulgarelli, A., Chen, A. W., Donnarumma, I., Giuliani, A., Longo, F., Pacciani, L., Pucella, G., Striani, E., Tavani, M., Vercellone, S., Vittorini, V., Covino, S., Krimm, H. A., Raiteri, C. M., Romano, P., Villata, M., D'Ammando, F., Bulgarelli, A., Chen, A. W., Donnarumma, I., Giuliani, A., Longo, F., Pacciani, L., Pucella, G., Striani, E., Tavani, M., Vercellone, S., Vittorini, V., Covino, S., Krimm, H. A., Raiteri, C. M., Romano, P., and Villata, M.
Abstract: During the first 3 years of operation the Gamma-Ray Imaging Detector onboard the AGILE satellite detected several blazars in a high gamma-ray activity: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae, Mrk 421, PKS 0537-441 and 4C +21.35. Thanks to the rapid dissemination of our alerts, we were able to obtain multiwavelength data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, and ARGO as well as radio-to-optical coverage by means of the GASP Project of the WEBT and the REM Telescope. This large multifrequency coverage gave us the opportunity to study the variability correlations between the emission at different frequencies and to obtain simultaneous spectral energy distributions of these sources from radio to gamma-ray energy bands, investigating the different mechanisms responsible for their emission and uncovering in some cases a more complex behaviour with respect to the standard models. We present a review of the most interesting AGILE results on these gamma-ray blazars and their multifrequency data., Comment: 25 pages, 10 figures, accepted for publication on Advances in Space Research. Talk presented at the 38th COSPAR Scientific Assembly (Bremen, Germany; July 18-25, 2010)
Published: 2011
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47. Discovery of Powerful Gamma-Ray Flares from the Crab Nebula

Author: Tavani, M., Bulgarelli, A., Vittorini, V., Pellizzoni, A., Striani, E., Caraveo, P., Weisskopf, M. C., 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, C. O., Trifoglio, M., Gianotti, F., Vercellone, S., Argan, A., Barbiellini, G., Cattaneo, P. W., Chen, A. W., Contessi, T., D'Ammando, F., DeParis, 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., Bignami, G. F., Tavani, M., Bulgarelli, A., Vittorini, V., Pellizzoni, A., Striani, E., Caraveo, P., Weisskopf, M. C., 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, C. O., Trifoglio, M., Gianotti, F., Vercellone, S., Argan, A., Barbiellini, G., Cattaneo, P. W., Chen, A. W., Contessi, T., D'Ammando, F., DeParis, 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, G. F.
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 MeV-10 GeV) flares observed by the AGILE satellite in September, 2010 and October, 2007. In both cases, the unpulsed flux increased by a factor of 3 compared to the non-flaring flux. The flare luminosity and short timescale favor an origin near the pulsar, and we discuss Chandra Observatory X-ray and HST 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 a ~1-day timescale., Comment: 23 pages (including Supporting On-line Material), 8 figures, 1 table. Version published in Science Express on January 6, 2011 (available at http://www.sciencemag.org/content/early/2011/01/05/science.1200083)
Published: 2011
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48. Multiwavelength observations of 3C 454.3. III. Eighteen months of agile monitoring of the 'Crazy Diamond'

Author: Vercellone, S., D'Ammando, F., Vittorini, V., Donnarumma, I., Pucella, G., Tavani, M., Ferrari, A., Raiteri, C. M., Villata, M., Romano, P., Krimm, H., Tiengo, A., Chen, A. W., Giovannini, G., Venturi, T., Giroletti, M., Kovalev, Y. Y., Sokolovsky, K., Pushkarev, A. B., Lister, M. L., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Cocco, V., Costa, E., Del Monte, E., De Paris, G., Di Cocco, G., Evangelista, Y., Feroci, M., Fiorini, M., Fornari, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Giuliani, A., Marisaldi, M., Mereghetti, S., Morselli, A., Pellizzoni, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Pittori, C., Verrecchia, F., Santolamazza, P., Giommi, P., Colafrancesco, S., Salotti, L., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Bachev, R., Beltrame, P., Benitez, E., Bottcher, M., Buemi, C. S., Calcidese, P., Capezzali, D., Carosati, D., Chen, W. P., Da Rio, D., Di Paola, A., Dolci, M., Dultzin, D., Forne, E., Gomez, J. L., Gurwell, M. A., Hagen-Thorn, V. A., Halkola, A., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Jorstad, S. G., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O., Lahteenmaki, A., Larionov, V. M., Leto, P., Ligustri, R., Lindfors, E., Lopez, J. M., Marscher, A. P., Mujica, R., Nikolashvili, M., Nilsson, K., Mommert, M., Palma, N., Pasanen, M., Roca-Sogorb, M., Ros, J. A., Roustazadeh, P., Sadun, A. C., Saino, J., Sigua, L., Sorcia, M., Takalo, L. O., Tornikoski, M., Trigilio, C., Turchetti, R., Umana, G., Vercellone, S., D'Ammando, F., Vittorini, V., Donnarumma, I., Pucella, G., Tavani, M., Ferrari, A., Raiteri, C. M., Villata, M., Romano, P., Krimm, H., Tiengo, A., Chen, A. W., Giovannini, G., Venturi, T., Giroletti, M., Kovalev, Y. Y., Sokolovsky, K., Pushkarev, A. B., Lister, M. L., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Cocco, V., Costa, E., Del Monte, E., De Paris, G., Di Cocco, G., Evangelista, Y., Feroci, M., Fiorini, M., Fornari, F., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Giuliani, A., Marisaldi, M., Mereghetti, S., Morselli, A., Pellizzoni, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Striani, E., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Pittori, C., Verrecchia, F., Santolamazza, P., Giommi, P., Colafrancesco, S., Salotti, L., Agudo, I., Aller, H. D., Aller, M. F., Arkharov, A. A., Bach, U., Bachev, R., Beltrame, P., Benitez, E., Bottcher, M., Buemi, C. S., Calcidese, P., Capezzali, D., Carosati, D., Chen, W. P., Da Rio, D., Di Paola, A., Dolci, M., Dultzin, D., Forne, E., Gomez, J. L., Gurwell, M. A., Hagen-Thorn, V. A., Halkola, A., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Jorstad, S. G., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O., Lahteenmaki, A., Larionov, V. M., Leto, P., Ligustri, R., Lindfors, E., Lopez, J. M., Marscher, A. P., Mujica, R., Nikolashvili, M., Nilsson, K., Mommert, M., Palma, N., Pasanen, M., Roca-Sogorb, M., Ros, J. A., Roustazadeh, P., Sadun, A. C., Saino, J., Sigua, L., Sorcia, M., Takalo, L. O., Tornikoski, M., Trigilio, C., Turchetti, R., and Umana, G.
Abstract: We report on 18 months of multiwavelength observations of the blazar 3C 454.3 ( Crazy Diamond) carried out in the period 2007 July-2009 January. In particular, we show the results of the AGILE campaigns which took place on 2008 May-June, 2008 July-August, and 2008 October-2009 January. During the 2008 May-2009 January period, the source average flux was highly variable, with a clear fading trend toward the end of the period, from an average. gamma-ray flux F-E>100 (MeV) greater than or similar to 200 x 10(-8) photons cm(-2) s(-1) in 2008 May-June, to F-E>100 MeV similar to 80 x 10(-8) photons cm(-2) s(-1) in 2008 October-2009 January. The average gamma-ray spectrum between 100 MeV and 1 GeV can be fit by a simple power law, showing a moderate softening ( from Gamma(GRID) similar to 2.0 to Gamma(GRID) similar to 2.2) toward the end of the observing campaign. Only 3 sigma upper limits can be derived in the 20-60 keV energy band with Super-AGILE, because the source was considerably off-axis during the whole time period. In 2007 July-August and 2008 May-June, 3C 454.3 was monitored by Rossi X-ray Timing Explorer (RXTE). The RXTE/Proportional Counter Array (PCA) light curve in the 3-20 keV energy band shows variability correlated with the gamma-ray one. The RXTE/PCA average flux during the two time periods is F3-20 keV = 8.4 x 10(-11) erg cm(-2) s(-1), and F3-20 keV = 4.5 x 10(-11) erg cm(-2) s(-1), respectively, while the spectrum ( a power law with photon index Gamma(PCA) = 1.65 +/- 0.02) does not show any significant variability. Consistent results are obtained with the analysis of the RXTE/High-Energy X-Ray Timing Experiment quasi-simultaneous data. We also carried out simultaneous Swift observations during all AGILE campaigns. Swift/XRT detected 3C 454.3 with an observed flux in the 2-10 keV energy band in the range (0.9-7.5) x 10(-11) erg cm(-2) s(-1) and a photon index in the range Gamma(XRT) = 1.33-2.04. In the 15-150 keV energy band, when detected, the source ha
Published: 2010

49. 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, P. W., Chen, A. W., 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, Elena, 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, G. F., 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, P. W., Chen, A. W., 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, Elena, 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, G. F.
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., QC 20120302
Published: 2010
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50. FERMI LARGE AREA TELESCOPE FIRST SOURCE CATALOG

Author: Abdo, A. A., Ackermann, M., Ajello, M., Allafort, A., Antolini, E., Atwood, W. B., Axelsson, Magnus, Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Belli, F., Berenji, B., Bisello, D., Blandford, R. D., Bloom, E. D., Bonamente, E., Bonnell, J., Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Busetto, G., Buson, S., Caliandro, G. A., Cameron, R. A., Campana, R., Canadas, B., Caraveo, P. A., Carrigan, S., Casandjian, J. M., Cavazzuti, E., Ceccanti, M., Cecchi, C., Celik, Oe., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Cillis, A. N., Ciprini, S., Claus, R., Cohen-Tanugi, J., Conrad, J., Corbet, R., Davis, D. S., DeKlotz, M., den Hartog, P. R., Dermer, C. D., de Angelis, A., de Luca, A., de Palma, F., Digel, S. W., Dormody, M., do Couto E Silva, E., Drell, P. S., Dubois, R., Dumora, D., Fabiani, D., Farnier, C., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Focke, W. B., Fortin, P., Frailis, M., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giavitto, G., Giebels, B., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grondin, M. -H, Grove, J. E., Guillemot, L., Guiriec, S., Gustafsson, M., Hadasch, D., Hanabata, Y., Harding, A. K., Hayashida, M., Hays, E., Healey, S. E., Hill, A. B., Horan, D., Hughes, R. E., Iafrate, G., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, T. J., Johnson, W. N., Kamae, T., Katagiri, H., Kataoka, J., Kawai, N., Kerr, M., Knoedlseder, J., Kocevski, D., Kuss, M., Lande, J., Landriu, D., Latronico, L., Lee, S. -H, Lemoine-Goumard, M., Lionetto, A. M., Garde, M. Llena, Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Makeev, A., Marangelli, B., Marelli, M., Massaro, E., Mazziotta, M. N., McConville, W., McEnery, J. E., Michelson, P. F., Minuti, M., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Mongelli, M., Monte, C., Monzani, M. E., Moretti, Elena, Morselli, A., Moskalenko, I. V., Murgia, S., Nakajima, H., Nakamori, T., Naumann-Godo, M., Nolan, P. L., Norris, J. P., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Ozaki, M., Paccagnella, A., Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce-Rollins, M., Pinchera, M., Piron, F., Porter, T. A., Poupard, L., Raino, S., Rando, R., Ray, P. S., Razzano, M., Razzaque, S., Rea, N., Reimer, A., Reimer, O., Reposeur, T., Ripken, J., Ritz, S., Rochester, L. S., Rodriguez, A. Y., Romani, R. W., Roth, M., Sadrozinski, H. F. -W, Salvetti, D., Sanchez, D., Sander, A., Parkinson, P. M. Saz, Scargle, J. D., Schalk, T. L., Scolieri, G., Sgro, C., Shaw, M. S., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Starck, J. -L, Stephens, T. E., Striani, E., Strickman, M. S., Strong, A. W., Suson, D. J., Tajima, H., Takahashi, H., Takahashi, T., Tanaka, T., Thayer, J. B., Thayer, J. G., Thompson, D. J., Tibaldo, L., Tibolla, O., Tinebra, F., Torres, D. F., Tosti, G., Tramacere, A., Uchiyama, Y., Usher, T. L., Van Etten, A., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wallace, E., Wang, P., Watters, K., Winer, B. L., Wood, K. S., Yang, Z., Ylinen, Tomi, Ziegler, M., Abdo, A. A., Ackermann, M., Ajello, M., Allafort, A., Antolini, E., Atwood, W. B., Axelsson, Magnus, Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Belli, F., Berenji, B., Bisello, D., Blandford, R. D., Bloom, E. D., Bonamente, E., Bonnell, J., Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Busetto, G., Buson, S., Caliandro, G. A., Cameron, R. A., Campana, R., Canadas, B., Caraveo, P. A., Carrigan, S., Casandjian, J. M., Cavazzuti, E., Ceccanti, M., Cecchi, C., Celik, Oe., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Cillis, A. N., Ciprini, S., Claus, R., Cohen-Tanugi, J., Conrad, J., Corbet, R., Davis, D. S., DeKlotz, M., den Hartog, P. R., Dermer, C. D., de Angelis, A., de Luca, A., de Palma, F., Digel, S. W., Dormody, M., do Couto E Silva, E., Drell, P. S., Dubois, R., Dumora, D., Fabiani, D., Farnier, C., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Focke, W. B., Fortin, P., Frailis, M., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giavitto, G., Giebels, B., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grondin, M. -H, Grove, J. E., Guillemot, L., Guiriec, S., Gustafsson, M., Hadasch, D., Hanabata, Y., Harding, A. K., Hayashida, M., Hays, E., Healey, S. E., Hill, A. B., Horan, D., Hughes, R. E., Iafrate, G., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, T. J., Johnson, W. N., Kamae, T., Katagiri, H., Kataoka, J., Kawai, N., Kerr, M., Knoedlseder, J., Kocevski, D., Kuss, M., Lande, J., Landriu, D., Latronico, L., Lee, S. -H, Lemoine-Goumard, M., Lionetto, A. M., Garde, M. Llena, Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Makeev, A., Marangelli, B., Marelli, M., Massaro, E., Mazziotta, M. N., McConville, W., McEnery, J. E., Michelson, P. F., Minuti, M., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Mongelli, M., Monte, C., Monzani, M. E., Moretti, Elena, Morselli, A., Moskalenko, I. V., Murgia, S., Nakajima, H., Nakamori, T., Naumann-Godo, M., Nolan, P. L., Norris, J. P., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Ozaki, M., Paccagnella, A., Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce-Rollins, M., Pinchera, M., Piron, F., Porter, T. A., Poupard, L., Raino, S., Rando, R., Ray, P. S., Razzano, M., Razzaque, S., Rea, N., Reimer, A., Reimer, O., Reposeur, T., Ripken, J., Ritz, S., Rochester, L. S., Rodriguez, A. Y., Romani, R. W., Roth, M., Sadrozinski, H. F. -W, Salvetti, D., Sanchez, D., Sander, A., Parkinson, P. M. Saz, Scargle, J. D., Schalk, T. L., Scolieri, G., Sgro, C., Shaw, M. S., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Starck, J. -L, Stephens, T. E., Striani, E., Strickman, M. S., Strong, A. W., Suson, D. J., Tajima, H., Takahashi, H., Takahashi, T., Tanaka, T., Thayer, J. B., Thayer, J. G., Thompson, D. J., Tibaldo, L., Tibolla, O., Tinebra, F., Torres, D. F., Tosti, G., Tramacere, A., Uchiyama, Y., Usher, T. L., Van Etten, A., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wallace, E., Wang, P., Watters, K., Winer, B. L., Wood, K. S., Yang, Z., Ylinen, Tomi, and Ziegler, M.
Abstract: We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), during the first 11 months of the science phase of the mission, which began on 2008 August 4. The First Fermi-LAT catalog (1FGL) contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range. Source detection was based on the average flux over the 11 month period, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4 sigma. The 1FGL catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and power-law spectral fits as well as flux measurements in five energy bands for each source. In addition, monthly light curves are provided. Using a protocol defined before launch we have tested for several populations of gamma-ray sources among the sources in the catalog. For individual LAT-detected sources we provide firm identifications or plausible associations with sources in other astronomical catalogs. Identifications are based on correlated variability with counterparts at other wavelengths, or on spin or orbital periodicity. For the catalogs and association criteria that we have selected, 630 of the sources are unassociated. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, with the result that 161 sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having properties that are strongly dependent on the model or as potentially being due to incorrectly modeled structure in the Galactic diffuse emission., QC 20101210
Published: 2010
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