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18 results on '"Striani E"'

1. 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., and Vercellone, S.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena
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

2. The Surprising Crab Nebula

Author

Striani, E., Tavani, M., and Vittorini, V.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena
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., 2012 Fermi Symposium proceedings - eConf C121028

Published
2013

3. 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., L., Pacciani, I., Donnarumma, K. D., Denney, R. J., Assef, Y., Ikejiri, M., Yamanaka, M., Uemura, A., Domingo, P., Giommi, A., Tarchi, F., Verrecchia, Longo, Francesco, S., Raino, M., Giusti, S., Vercellone, A. W., Chen, E., Striani, V., Vittorini, M., Tavani, A., Bulgarelli, A., Giuliani, G., Pucella, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, S., Colafrancesco, E., Costa, Paris, G., E. D., Monte, G. D., Cocco, Y., Evangelista, A., Ferrari, M., Feroci, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, D., Zanello, C., Pittori, P., Santolamazza, F., Lucarelli, L., Salotti, and G., Valentini

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Cosmology and Nongalactic Astrophysics (astro-ph.CO), gamma-ray flaring, general [quasars], Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, individual: GB6 J1239+0443 [galaxies], Astrophysics::Cosmology and Extragalactic Astrophysics, AGILE satellite, radiation mechanisms, black hole, blazar, radiation mechanisms: non-thermal, non-thermal [radiation mechanisms], galaxies: individual: GB6 J1239+0443, quasars: general, active [galaxies], astro-ph.CO, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
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

4. AGILE detection of Cygnus X-3 ��-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., L��hteenm��ki, 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.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), FOS: Physical sciences
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 ��-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 ��-ray monitoring of Cyg X-3 as well as the results from extensive multiwavelength campaigns involving radio (RATAN-600, AMI-LA and Mets��hovi Radio Observatories) and X-ray monitoring data (XTE and Swift). We detect a series of repeated ��-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 ��-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 ��-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 ��-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., 16 pages, 8 figures, 7 tables; A&A (2011)

Published
2011
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5. Magic Constraints on γ-ray Emission from Cygnus X-3

Author

Aleksic, J, Antonelli, La, Antoranz, P, Backes, M, Baixeras, C, Barrio, Ja, Bastieri, Denis, Gonzalez, Jb, Bednarek, W, Berdyugin, A, Berger, K, Bernardini, E, Biland, A, Blanch, O, Bock, Rk, Boller, A, Bonnoli, G, Bordas, P, Tridon, Db, BOSCH RAMON, V, Bose, D, Braun, I, Bretz, T, Britzger, D, Camara, M, Carmona, E, Carosi, A, Colin, P, Contreras, Jl, Cortina, J, Costado, Mt, Covino, S, Dazzi, F, DE ANGELIS, A, DEL POZO EDC, DE LOTTO, B, DE MARIA, M, DE SABATA, F, Mendez, Cd, Doert, M, Dominguez, A, Prester, Dd, Dorner, D, Doro, Michele, Elsaesser, D, Errando, M, Ferenc, D, Fonseca, Mv, Font, L, Lopez, Rjg, Garczarczyk, M, Gaug, M, Godinovic, N, Goebel, F, Hadasch, D, Herrero, A, Hildebrand, D, HOHNE MONCH, D, Hose, J, Hrupec, D, Hsu, Cc, Jogler, T, Klepser, S, Krahenbuhl, T, Kranich, D, LA BARBERA, A, Laille, A, Leonardo, E, Lindfors, E, Lombardi, S, Longo, F, Lopez, M, Lorenz, E, Majumdar, P, Maneva, G, Mankuzhiyil, N, Mannheim, K, Maraschi, L, Mariotti, Mose', Martinez, M, Mazin, D, Meucci, M, Miranda, Jm, Mirzoyan, R, Miyamoto, H, Moldon, J, Moles, M, Moralejo, A, Nieto, D, Nilsson, K, Ninkovic, J, Orito, R, Oya, I, Paiano, S, Paoletti, R, Paredes, Jm, Partini, S, Pasanen, M, Pascoli, Donatella, Pauss, F, Pegna, Rg, PEREZ TORRES MA, Persic, M, Peruzzo, L, Prada, F, Prandini, Elisa, Puchades, N, Puljak, I, Reichardt, I, Rhode, W, Ribo, M, Rico, J, Rissi, M, Rugamer, S, Saggion, Antonio, Saito, K, Saito, Ty, Salvati, M, SANCHEZ CONDE, M, Satalecka, K, Scalzotto, VILLI MARIO, Scapin, V, Schultz, C, Schweizer, T, Shayduk, M, Shore, Sn, SIERPOWSKA BARTOSIK, A, Sillanpaa, A, Sitarek, J, Sobczynska, D, Spanier, F, Spiro, S, Stamerra, A, Steinke, B, Struebig, Jc, Suric, T, Takalo, L, Tavecchio, F, Temnikov, P, Terzic, T, Tescaro, D, Teshima, M, Torres, Df, Vankov, H, Wagner, Rm, Weitzel, Q, Zabalza, V, Zandanel, F, Zanin, R, Bulgarelli, A, MAX MOERBECK, W, Piano, G, Pooley, G, Readhead, Acs, Richards, Jl, Sabatini, S, Striani, E, Tavani, M, Trushkin, S., J., Aleksic, L. A., Antonelli, P., Antoranz, M., Backe, C., Baixera, J. A., Barrio, D., Bastieri, J. B., Gonzalez, W., Bednarek, A., Berdyugin, K., Berger, E., Bernardini, A., Biland, O., Blanch, R. K., Bock, A., Boller, G., Bonnoli, P., Borda, D. B., Tridon, V., Bosch Ramon, D., Bose, I., Braun, T., Bretz, D., Britzger, M., Camara, E., Carmona, A., Carosi, P., Colin, J. L., Contrera, J., Cortina, M. T., Costado, S., Covino, F., Dazzi, A. D., Angeli, E. D. C., Del Pozo, B. D., Lotto, M. D., Maria, F. D., Sabata, C. D., Mendez, M., Doert, A., Dominguez, D. D., Prester, D., Dorner, M., Doro, D., Elsaesser, M., Errando, D., Ferenc, M. V., Fonseca, L., Font, R. J. G., Lopez, M., Garczarczyk, M., Gaug, N., Godinovic, F., Goebel, D., Hadasch, A., Herrero, D., Hildebrand, D., Hohne Monch, J., Hose, D., Hrupec, C. C., Hsu, T., Jogler, S., Klepser, T., Krahenbuhl, D., Kranich, A. L., Barbera, A., Laille, E., Leonardo, E., Lindfor, S., Lombardi, Longo, Francesco, M., Lopez, E., Lorenz, P., Majumdar, G., Maneva, N., Mankuzhiyil, K., Mannheim, L., Maraschi, M., Mariotti, M., Martinez, D., Mazin, M., Meucci, J. M., Miranda, R., Mirzoyan, H., Miyamoto, J., Moldon, M., Mole, A., Moralejo, D., Nieto, K., Nilsson, J., Ninkovic, R., Orito, I., Oya, S., Paiano, R., Paoletti, J. M., Parede, S., Partini, M., Pasanen, D., Pascoli, F., Pau, R. G., Pegna, M. A., Perez Torre, M., Persic, L., Peruzzo, F., Prada, E., Prandini, N., Puchade, I., Puljak, I., Reichardt, W., Rhode, M., Ribo, J., Rico, M., Rissi, S., Rugamer, A., Saggion, K., Saito, T. Y., Saito, M., Salvati, M., Sanchez Conde, K., Satalecka, V., Scalzotto, V., Scapin, C., Schultz, T., Schweizer, M., Shayduk, S. N., Shore, A., Sierpowska Bartosik, A., Sillanpaa, J., Sitarek, D., Sobczynska, F., Spanier, S., Spiro, A., Stamerra, B., Steinke, J. C., Struebig, T., Suric, L., Takalo, F., Tavecchio, P., Temnikov, T., Terzic, D., Tescaro, M., Teshima, D. F., Torre, H., Vankov, R. M., Wagner, Q., Weitzel, V., Zabalza, F., Zandanel, R., Zanin, A., Bulgarelli, W., Max Moerbeck, G., Piano, G., Pooley, A. C. S., Readhead, J. L., Richard, S., Sabatini, E., Striani, M., Tavani, and S., Trushkin

Subjects
Photon, HIGH-ENERGY EMISSION, MICROQUASAR GRS 1915+105, X-RAY, RELATIVISTIC JET, CYG X-3, RADIO OUTBURST, CRAB-NEBULA, BINARY, TELESCOPE, PULSAR, Astrophysics, 01 natural sciences, law.invention, Raigs gamma, law, Observacions astronòmiques, 010303 astronomy & astrophysics, Estels binaris de raigs X, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Very High Energy Gamma-ray Astronomy, MAGIC telescope, Black Holes, Gamma ray, X-ray binaries, Electrónica, Física nuclear, Radio frequency, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Astronomical observations, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Compact star, Radiation, gamma ray astronomy, Cosmic rays, IMAGING CHERENKOV DETECTOR, Telescope, 0103 physical sciences, acceleration of particles, binaries: general, gamma rays: observations, X-rays: bina- ries — X-rays: individual (Cygnus X-3), Cherenkov radiation, Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, Gamma rays, Magic (programming), Astronomy, Astronomy and Astrophysics, Space and Planetary Science
Abstract

Cygnus X-3 is a microquasar consisting of an accreting compact object orbiting around a Wolf-Rayet star. It has been detected at radio frequencies and up to high-energy gamma rays (above 100 MeV). However, many models also predict a very high energy (VHE) emission (above hundreds of GeV) when the source displays relativistic persistent jets or transient ejections. Therefore, detecting such emission would improve the understanding of the jet physics. The imaging atmospheric Cherenkov telescope MAGIC observed Cygnus X-3 for about 70 hours between 2006 March and 2009 August in different X-ray/radio spectral states and also during a period of enhanced gamma-ray emission. MAGIC found no evidence for a VHE signal from the direction of the microquasar. An upper limit to the integral flux for energies higher than 250 GeV has been set to 2.2 x 10-12 photons cm-2 s-1 (95% confidence level). This is the best limit so far to the VHE emission from this source. The non-detection of a VHE signal during the period of activity in the high-energy band sheds light on the location of the possible VHE radiation favoring the emission from the innermost region of the jets, where absorption is significant. The current and future generations of Cherenkov telescopes may detect a signal under precise spectral conditions., 14 pages, 11 figures, This manuscript has been accepted by ApJ (2010)

Published
2010
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6. Discovery of extreme particle acceleration in the microquasar Cygnus X-3

Author

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

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The study of relativistic particle acceleration is a major topic of high-energy astrophysics. It is well known that massive black holes in active galaxies can release a substantial fraction of their accretion power into energetic particles, producing gamma-rays and relativistic jets. Galactic microquasars (hosting a compact star of 1-10 solar masses which accretes matter from a binary companion) also produce relativistic jets. However, no direct evidence of particle acceleration above GeV energies has ever been obtained in microquasar ejections, leaving open the issue of the occurrence and timing of extreme matter energization during jet formation. Here we report the detection of transient gamma-ray emission above 100 MeV from the microquasar Cygnus X-3, an exceptional X-ray binary which sporadically produces powerful radio jets. Four gamma-ray flares (each lasting 1-2 days) were detected by the AGILE satellite simultaneously with special spectral states of Cygnus X-3 during the period mid-2007/mid-2009. Our observations show that very efficient particle acceleration and gamma-ray propagation out of the inner disk of a microquasar usually occur a few days before major relativistic jet ejections. Flaring particle energies can be thousands of times larger than previously detected maximum values (with Lorentz factors of 105 and 102 for electrons and protons, respectively). We show that the transitional nature of gamma-ray flares and particle acceleration above GeV energies in Cygnus X-3 is clearly linked to special radio/X-ray states preceding strong radio flares. Thus gamma-rays provide unique insight into the nature of physical processes in microquasars., 29 pages (including Supplementary Information), 8 figures, 2 tables version submitted to Nature on August 7, 2009 (accepted version available at http://www.nature.com/nature/journal/vaop/ncurrent/pdf/nature08578.pdf)

Published
2009

7. Gamma-ray blazars: The view from AGILE

Author

Filippo D'Ammando, F. Longo, P. Romano, Marco Tavani, Andrea Bulgarelli, S. Vercellone, Luigi Pacciani, C. M. Raiteri, Stefano Covino, V. Vittorini, E. Striani, Hans A. Krimm, A. W. Chen, M. Villata, G. Pucella, I. Donnarumma, A. Giuliani, F., D'Ammando, A., Bulgarelli, A. W., Chen, I., Donnarumma, A., Giuliani, Longo, Francesco, L., Pacciani, G., Pucella, E., Striani, M., Tavani, S., Vercellone, V., Vittorini, S., Covino, H. A., Krimm, C. M., Raiteri, P., Romano, M., Villata, DAmmando F, Bulgarelli A, Chen AW, Donnarumma I, Giuliani A, Longo F, Pacciani L, Pucella G, Striani E, Tavani M, Vercellone S, Vittorini V, Covino S, Krimm HA, Raiteri CM, Romano P, and Villata M

Subjects
Atmospheric Science, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, FOS: Physical sciences, Aerospace Engineering, Astrophysics, High Energy Gamma-ray Astronomy, law.invention, Telescope, Gamma-ray sources, Quasars, Active galactic nuclei, BL Lac objects, Blazars, law, MAGIC (telescope), Blazar, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Detector, Gamma ray, Astronomy, Active Galactic Nuclei, Astronomy and Astrophysics, Quasar, Geophysics, Space and Planetary Science, General Earth and Planetary Sciences, Satellite, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
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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8. The AGILE observations of the hard and bright GRB 100724B

Author

P. Santolamazza, M. Galli, Piergiorgio Picozza, S. Cutini, F. Verrecchia, V. Vittorini, Paolo Giommi, M. Trifoglio, F. Perotti, E. Striani, Sandro Mereghetti, I. Lapshov, P. W. Cattaneo, A. W. Chen, Elena Moretti, Fulvio Gianotti, M. Prest, E. Del Monte, Francesco Lazzarotto, A. Rappoldi, E. Vallazza, G. Di Cocco, Marco Feroci, Filippo D'Ammando, Paolo Soffitta, Luigi Pacciani, Guido Barbiellini, Paolo Lipari, I. Donnarumma, C. Labanti, Francesco Longo, A. Morselli, Maura Pilia, A. Argan, Andrea Bulgarelli, Alessio Trois, P. A. Caraveo, Enrico Costa, S. Vercellone, G. Piano, Marco Tavani, S. Sabatini, Martino Marisaldi, L. A. Antonelli, L. Salotti, Massimo Rapisarda, Y. Evangelista, A. Giuliani, C. Pittori, A. Pellizzoni, G. Pucella, F. Fuschino, 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 PW, Chen AW, Costa E, DAmmando 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 LA, Cutini S, Pittori C, Santolamazza P, Verrecchia F, Giommi P, Salotti L, E., Del Monte, G., Barbiellini, I., Donnarumma, F., Fuschino, A., Giuliani, Longo, Francesco, M., Marisaldi, G., Pucella, M., Tavani, M., Trifoglio, A., Troi, A., Argan, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, A. W., Chen, E., Costa, F., D'Ammando, Cocco, G., Y., Evangelista, M., Feroci, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, S., Mereghetti, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, S., Sabatini, P., Soffitta, E., Striani, E., Vallazza, S., Vercellone, V., Vittorini, L. A., Antonelli, S., Cutini, C., Pittori, P., Santolamazza, F., Verrecchia, P., Giommi, and L., Salotti

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Astrophysics, gamma-ray burst: individual: GRB 100724B, individual: GRB 100724B [gamma-ray burst], emission at MeV and GeV, gamma ray burst, symbols.namesake, Observatory, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Cross-correlation, AGILE satellite, Astronomy and Astrophysics, gamma rays: general, gamma rays: general / gamma-ray burst: individual: GRB 100724B, Lorentz factor, Space and Planetary Science, symbols, Gamma-ray burst, Interplanetary spaceflight, Astrophysics - High Energy Astrophysical Phenomena, Event (particle physics), general [gamma rays], Fermi Gamma-ray Space Telescope
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., 8 pages, 5 figures. Accepted for publication by A&A. Final version after the correction by the language editor

Published
2011

9. Study of the γ-ray source 1AGL J2022+4032 in the Cygnus region

Author

F. Longo, Elsa Beatriz Giacani, G. Piano, Arnaud Ferrari, A. Zambra, F. D'Ammando, C. Pittori, M. Feroci, M. Fiorini, P. Picozza, M. Rapisarda, G. De Paris, Gloria Mabel Dubner, A. Pellizzoni, E. Costa, E. Del Monte, G. Pucella, V. Vittorini, F. Perotti, A. Trois, M. Trifoglio, A. Morselli, M. Tavani, E. Vallazza, F. Gianotti, P. A. Caraveo, A. Argan, M. Pilia, A. Giuliani, Francesco Lucarelli, P. Soffitta, Andrea Bulgarelli, F. Lazzarotto, F. Fuschino, S. Vercellone, P. Lipari, P. Santolamazza, A. Rappoldi, E. Scalise, E. Striani, M. Giusti, L. Pacciani, P. W. Cattaneo, A. W. Chen, L. A. Antonelli, M. Galli, F. Verrecchia, M. Prest, S. Sabatini, P. Giommi, E. Moretti, Claudio Labanti, L. Salotti, D. Zanello, G. Di Cocco, Sandro Mereghetti, I. Donnarumma, Y. Evangelista, S. Colafrancesco, Martino Marisaldi, G. Barbiellini, A. W., Chen, G., Piano, M., Tavani, A., Troi, G., Dubner, E., Giacani, A., Argan, G., Barbiellini, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, E., Costa, F., D'Ammando, Paris, G., Monte, E., Cocco, G., I., Donnarumma, Y., Evangelista, M., Feroci, A., Ferrari, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, A., Giuliani, M., Giusti, C., Labanti, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, S., Sabatini, E., Scalise, P., Soffitta, E., Striani, M., Trifoglio, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, P., Giommi, F., Verrecchia, F., Lucarelli, P., Santolamazza, S., Colafrancesco, L. A., Antonelli, L., Salotti, Chen AW, Piano G, Tavani M, Trois A, Dubner G, Giacani E, Argan A, Barbiellini G, Bulgarelli A, Caraveo P, Cattaneo PW, Costa E, DAmmando F, De Paris G, Del Monte E, Di Cocco G, Donnarumma I, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Fuschino F, Galli M, Gianotti F, Giuliani A, Giusti M, Labanti C, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mereghetti S, Moretti E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Pilia M, Prest M, Pucella G, Rapisarda M, Rappoldi A, Sabatini S, Scalise E, Soffitta P, Striani E, Trifoglio M, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Giommi P, Verrecchia F, Lucarelli F, Santolamazza P, Colafrancesco S, Antonelli LA, and Salotti L

Subjects
pulsars: individual: 1FGL J2021.5+4026, Astrophysics::High Energy Astrophysical Phenomena, Ciencias Físicas, pulsars: individual: 1AGL J2022+4032, gamma rays: stars, pulsars: individual: LAT PSR J2021+4026, pulsars: individual: 3EG J2020+4017, individual: LAT PSR J2021+4026 [pulsars], Flux, FOS: Physical sciences, Astrophysics, star [gamma rays], law.invention, Telescope, purl.org/becyt/ford/1 [https], Pulsar, law, Blazar, Supernova remnant, individual: 1FGL J2021.5+4026 [pulsars], Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Gamma ray, Astronomy and Astrophysics, individual: 3EG J2020+4017 [pulsars], purl.org/becyt/ford/1.3 [https], Light curve, stars [gamma rays], Astronomía, gamma ray, Space and Planetary Science, AGILE satellite, galactic source, supernova remnant Gamma Cygni, individual: 1AGL J2022+4032 [pulsars], pulsars: individual: 1AGL J2022+4032 / gamma rays: stars / pulsars: individual: 1FGL J2021.5+4026 / pulsars: individual: LAT PSR J2021+4026 / pulsars: individual: 3EG J2020+4017, Astrophysics - High Energy Astrophysical Phenomena, CIENCIAS NATURALES Y EXACTAS, Fermi Gamma-ray Space Telescope
Abstract

Identification of gamma-ray-emitting Galactic sources is a long-standing problem in astrophysics. One such source, 1AGL J2022+4032, coincident with the interior of the radio shell of the supernova remnant Gamma Cygni (SNR G78.2+2.1) in the Cygnus Region, has recently been identified by Fermi as a gamma-ray pulsar, LAT PSR J2021+4026. We present long-term observations of 1AGL J2022+4032 with the AGILE gamma-ray telescope, measuring its flux and light curve. We compare the light curve of 1AGL J2022+4032 with that of 1AGL J2021+3652 (PSR J2021+3651), showing that the flux variability of 1AGL J2022+4032 appears to be greater than the level predicted from statistical and systematic effects and producing detailed simulations to estimate the probability of the apparent observed variability. We evaluate the possibility that the gamma-ray emission may be due to the superposition of two or more point sources, some of which may be variable, considering a number of possible counterparts. We consider the possibility of a nearby X-ray quiet microquasar contributing to the flux of 1AGL J2022+4032 to be more likely than the hypotheses of a background blazar or intrinsic gamma-ray variabilty of LAT PSR J2021+4026., 7 pages, 7 figures, accepted for publication in Astronomy & Astrophysics

Published
2010

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

Author

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

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

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

Published
2010
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11. A year-long AGILE observation of Cygnus X-1 in hard spectral state

Author

A. W. Chen, Francesco Lazzarotto, A. Morselli, Marco Feroci, Luigi Pacciani, E. Striani, S. Vercellone, M. Prest, C. Pittori, I. Lapshov, I. Donnarumma, E. Del Monte, Sandro Mereghetti, A. Argan, M. Galli, P. W. Cattaneo, Piergiorgio Picozza, Massimo Rapisarda, F. Fuschino, Andrea Bulgarelli, F. Perotti, A. Pellizzoni, G. Di Cocco, F. Verrecchia, Enrico Costa, Elena Moretti, Filippo D'Ammando, G. Piano, A. Rappoldi, E. Vallazza, S. Cutini, A. Giuliani, P. A. Caraveo, L. Salotti, Paolo Soffitta, Claudio Labanti, A. Zambra, Francesco Longo, L. A. Antonelli, Guido Barbiellini, Martino Marisaldi, Paolo Lipari, P. Santolamazza, Paolo Giommi, Marco Tavani, S. Sabatini, V. Vittorini, M. Trifoglio, Maura Pilia, Alessio Trois, Fulvio Gianotti, B. Preger, F. Boffelli, Y. Evangelista, G. Pucella, Del Monte E, Feroci M, Evangelista Y, Costa E, Donnarumma I, Lapshov I, Lazzarotto F, Pacciani L, Rapisarda M, Soffitta P, Argan A, Barbiellini G, Boffelli F, Bulgarelli A, Caraveo P, Cattaneo PW, Chen A, DAmmando F, Di Cocco G, Fuschino F, Galli M, Gianotti F, Giuliani A, Labanti C, Lipari P, Longo F, Marisaldi M, Mereghetti S, Moretti E, Morselli A, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Prest M, Pucella G, Rappoldi A, Sabatini S, Striani E, Tavani M, Trifoglio M, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Antonelli LA, Cutini S, Pittori C, Preger B, Santolamazza P, Verrecchia F, Giommi P, Salotti L, E. D., Monte, M., Feroci, Y., Evangelista, E., Costa, I., Donnarumma, I., Lapshov, F., Lazzarotto, L., Pacciani, M., Rapisarda, P., Soffitta, A., Argan, G., Barbiellini, F., Boffelli, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, A., Chen, F., D'Ammando, G. D., Cocco, F., Fuschino, M., Galli, F., Gianotti, A., Giuliani, C., Labanti, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, E., Moretti, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, G., Pucella, A., Rappoldi, S., Sabatini, E., Striani, M., Tavani, M., Trifoglio, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, L. A., Antonelli, S., Cutini, C., Pittori, B., Preger, P., Santolamazza, F., Verrecchia, P., Giommi, and L., Salotti

Subjects
Agile, Black Holes, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Phase (waves), Flux, FOS: Physical sciences, Astrophysics, cignus, High Energy Gamma-ray Astronomy, X-ray, binaries, silicon detector, Range (statistics), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Autocorrelation, Gamma ray, Static timing analysis, Astronomy and Astrophysics, stars: individual: Cyg X-1, gamma rays: observations, X-rays: binaries, X-rays: general, Space and Planetary Science, AGILE satellite, Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing)
Abstract

We present the observation of Cyg X-1 in hard spectral state performed during the AGILE Science Verification Phase and Observing Cycle 1 in hard X-rays (with SuperAGILE) and gamma rays (with the GRID) and lasting for about 160 days with a live time of $\sim 6$ Ms. We investigate the variability of Cyg X-1 in hard X-rays at different timescales, from $\sim 300$ s up to one day, and we apply different tools of timing analysis, such as the autocorrelation function, the first order structure function and the Lomb-Scargle periodogram, to our data (from SuperAGILE) and to the simultaneous data in soft X-rays (from RXTE/ASM). We conclude our investigation with a search for emission in the energy range above 100 MeV with the maximum likelihood technique. In the hard X-ray band the flux of Cyg X-1 shows its typical erratic fluctuations at all timescales with variations of about a factor of two that do not affect significantly the shape of the energy spectrum. From the first order structure function we find that the X-ray emission of Cyg X-1 is characterized by \textit{antipersistence}, indication of a negative feedback mechanism at work. In the gamma ray data a statistically significant point-like source at the position of Cyg X-1 is not found and the upper limit on the flux is $\mathrm{5 \times 10^{-8} \; ph \; cm^{-2} \; s^{-1}}$, over the whole observation (160 days). Finally we compare our upper limit in gamma rays with the expectation of various models of the Cyg X-1 emission, of both hadronic and leptonic origin, in the GeV -- TeV band. The time history of Cyg X-1 in the hard X-ray band over 13 months (not continuous) is shown. Different tools of analysis do not provide fully converging results of the characteristic timescales in the system, suggesting that the timescales found in the structure function are not intrinsic to the physics of the source., Comment: 15 pages and 11 figures (with subfigures). Accepted for publication by A&A.

Published
2010

12. TEMPORAL PROPERTIES OF GX 301-2 OVER A YEAR-LONG OBSERVATION WITH SuperAGILE

Author

A. Pellizzoni, F. Fuschino, L. A. Antonelli, A. W. Chen, S. Cutini, Paolo Soffitta, G. Pucella, Marco Feroci, Luigi Pacciani, F. Perotti, P. Santolamazza, M. Prest, E. Striani, M. Galli, A. Argan, Piergiorgio Picozza, Paolo Lipari, Francesco Lazzarotto, I. Lapshov, Andrea Bulgarelli, F. Verrecchia, Filippo D'Ammando, Enrico Costa, Marco Tavani, G. Di Cocco, G. Piano, S. Sabatini, Massimo Rapisarda, Paolo Giommi, A. Morselli, Francesco Longo, Sandro Mereghetti, F. Boffelli, P. W. Cattaneo, Y. Evangelista, A. Giuliani, Guido Barbiellini, E. Del Monte, Martino Marisaldi, S. Vercellone, L. Salotti, A. Zambra, I. Donnarumma, P. A. Caraveo, Claudio Labanti, Elena Moretti, A. Rappoldi, E. Vallazza, Fulvio Gianotti, V. Vittorini, M. Trifoglio, Maura Pilia, Alessio Trois, B. Preger, C. Pittori, Y., Evangelista, M., Feroci, E., Costa, E. D., Monte, I., Donnarumma, I., Lapshov, F., Lazzarotto, L., Pacciani, M., Rapisarda, P., Soffitta, A., Argan, G., Barbiellini, F., Boffelli, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, A., Chen, F., D'Ammando, G. D., Cocco, F., Fuschino, M., Galli, F., Gianotti, A., Giuliani, C., Labanti, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, E., Moretti, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, G., Pucella, A., Rappoldi, S., Sabatini, E., Striani, M., Tavani, M., Trifoglio, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, L. A., Antonelli, S., Cutini, C., Pittori, B., Preger, P., Santolamazza, F., Verrecchia, P., Giommi, L., Salotti, Evangelista Y, Feroci M, Costa E, Del Monte E, Donnarumma I, Lapshov I, Lazzarotto F, Pacciani L, Rapisarda M, Soffitta P, Argan A, Barbiellini G, Boffelli F, Bulgarelli A, Caraveo P, Cattaneo PW, Chen A, DAmmando F, Di Cocco G, Fuschino F, Galli M, Gianotti F, Giuliani A, Labanti C, Lipari P, Longo F, Marisaldi M, Mereghetti S, Moretti E, Morselli A, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Prest M, Pucella G, Rappoldi A, Sabatini S, Striani E, Tavani M, Trifoglio M, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Antonelli LA, Cutini S, Pittori C, Preger B, Santolamazza P, Verrecchia F, Giommi P, and Salotti L

Subjects
Agile, SuperAGILE, Astrophysics::High Energy Astrophysical Phenomena, Phase (waves), Flux, FOS: Physical sciences, X-ray binary GX 301-2, pulsar, Astrophysics, High Mass X-ray Binaries, High Energy Gamma-ray Astronomy, law.invention, stars: neutron, X-rays: binaries, Pulsar, law, pulsars: individual (GX 3012), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Accretion (meteorology), Astronomy and Astrophysics, AGILE satellite, Light curve, Orbital period, Secular variation, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, Flare
Abstract

We present the long-term monitoring of the High Mass X-ray Binary GX 301-2 performed with the SuperAGILE instrument on-board the AGILE mission. The source was monitored in the 20-60 keV energy band during the first year of the mission from 2007 July 17 to 2008 August 31, covering about one whole orbital period and three more pre-periastron passages for a total net observation time of about 3.7 Ms. The SuperAGILE dataset represents one of the most continuous and complete monitoring at hard X-ray energies of the 41.5 day long binary period available to date. The source behavior was characterized at all orbital phases in terms of hard X-ray flux, spectral hardness, spin period history, pulsed fraction and pulse shape profile. We also complemented the SuperAGILE observations with the soft X-ray data of the RossiXTE/ASM. Our analysis shows a clear orbital modulation of the spectral hardness, with peaks in correspondence with the pre-periastron flare and near phase 0.25. The hardness peaks we found could be related with the wind-plus-stream accretion model proposed in order to explain the orbital light curve modulation of GX 301-2. Timing analysis of the pulsar spin period shows that the secular trend of the about 680 s pulse period is consistent with the previous observations, although there is evidence of a slight decrease in the spin-down rate. The analysis of the hard X-ray pulsed emission also showed a variable pulse shape profile as a function of the orbital phase, with substructures detected near the passage at the periastron, and a clear modulation of the pulsed fraction, which appears in turn strongly anti-correlated with the source intensity., 10 pages, 7 figures, 3 tables, accepted for publication in ApJ

Published
2010

13. Episodic Transient Gamma-Ray Emission From The Microquasar Cygnus X-1

Author

E. Moretti, V. Vittorini, Claudio Labanti, A. Giuliani, M. Trifoglio, C. Pittori, Francesco Lazzarotto, Paolo Lipari, Martino Marisaldi, Attilio Ferrari, Guido Barbiellini, P. Santolamazza, A. Pellizzoni, F. Perotti, S. Vercellone, M. Galli, Piergiorgio Picozza, E. Striani, Y. Evangelista, M. Giusti, Francesco Longo, Alda Rubini, F. Verrecchia, Ennio Morelli, Paolo Giommi, G. De Paris, Massimiliano Fiorini, Marco Tavani, F. Fuschino, G. Di Cocco, A. Rappoldi, E. Vallazza, S. Sabatini, Sergio Colafrancesco, Fulvio Gianotti, A. Argan, Sandro Mereghetti, P. W. Cattaneo, Andrea Bulgarelli, A. Morselli, I. Donnarumma, Enrico Costa, Filippo D'Ammando, Marco Feroci, Luigi Pacciani, M. Prest, Paolo Soffitta, L. A. Antonelli, A. W. Chen, E. Del Monte, Massimo Rapisarda, G. Piano, P. A. Caraveo, Maura Pilia, D. Zanello, G. Pucella, Alessio Trois, E. Scalise, L. Salotti, A. Zambra, F. de Pasquale, Sabatini S, Tavani M, Striani E, Bulgarelli A, Vittorini V, Piano G, Del Monte E, Feroci M, de Pasquale F, Trifoglio M, Gianotti F, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Chen AW, DAmmando F, Costa E, De Paris G, Di Cocco G, Donnarumma I, Evangelista Y, Ferrari A, Fiorini M, Fuschino F, Galli M, Giuliani A, Giusti M, Labanti C, 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, Pucella G, Prest M, Rapisarda M, Rappoldi A, Rubini A, Scalise E, Soffitta P, Trois A, Vallazza E, Vercellone S, Zambra A, Zanello D, Pittori C, Verrecchia F, Santolamazza P, Giommi P, Colafrancesco S, Antonelli LA, Salotti L, S., Sabatini, M., Tavani, E., Striani, A., Bulgarelli, V., Vittorini, G., Piano, E. D., Monte, M., Feroci, F. d., Pasquale, M., Trifoglio, F., Gianotti, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, A. W., Chen, F., D'Ammando, E., Costa, G. D., Pari, G. D., Cocco, I., Donnarumma, Y., Evangelista, A., Ferrari, M., Fiorini, F., Fuschino, M., Galli, A., Giuliani, M., Giusti, C., Labanti, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, G., Pucella, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, E., Scalise, P., Soffitta, A., Troi, E., Vallazza, S., Vercellone, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, P., Santolamazza, P., Giommi, S., Colafrancesco, L. A., Antonelli, and L., Salotti

Subjects
Agile, Black Holes, transient gamma-ray emission, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Astrophysics, High Energy Gamma-ray Astronomy, X-rays: binaries, Cutoff, Cygnus X-1, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Range (particle radiation), Gamma ray, Astronomy and Astrophysics, gamma rays: general, stars: individual (Cygnus X-1), Galaxy, Black hole, Space and Planetary Science, AGILE satellite, Transient (oscillation), Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing)
Abstract

Cygnus X-1 is the archetypal black hole (BH) binary system in our Galaxy. We report the main results of an extensive search for transient gamma-ray emission from Cygnus X-1 carried out in the energy range 100 MeV - 3 GeV by the AGILE satellite, during the period 2007 July - 2009 October. The total exposure time is about 300 days, during which the source was in the "hard" X-ray spectral state. We divided the observing intervals in 2 or 4 week periods, and searched for transient and persistent emission. We report an episode of significant transient gamma-ray emission detected on 2009, October 16 in a position compatible with Cygnus X-1 optical position. This episode, occurred during a hard spectral state of Cygnus X-1, shows that a 1-2 day time variable emission above 100 MeV can be produced during hard spectral states, having important theoretical implications for current Comptonization models for Cygnus X-1 and other microquasars. Except for this one short timescale episode, no significant gamma-ray emission was detected by AGILE. By integrating all available data we obtain a 2$\sigma$ upper limit for the total integrated flux of $F_{\gamma,U.L.} = 3 \times 10^{-8} \rm ph cm^{-2} s^{-1}$ in the energy range 100 MeV - 3 GeV. We then clearly establish the existence of a spectral cutoff in the energy range 1-100 MeV that applies to the typical hard state outside the flaring period and that confirms the historically known spectral cutoff above 1 MeV., Comment: Accepted for publication by ApJ on the 9th of Feb 2010, 5 pages, 3 figures

Published
2010

14. Discovery Of Pulsations From The Pulsar J0205+6449 In Snr 3c 58 With The Fermi Gamma-Ray Space Telescope

Author

C. Monte, Seth Digel, M. Dormody, Jun Kataoka, W. N. Johnson, Denis Bastieri, Alessandro Brez, J. Lande, Sylvain Guiriec, P. M. Saz Parkinson, Randall P. Johnson, P. Fusco, Victoria M. Kaspi, Ö. Çelik, A. S. Johnson, Jürgen Knödlseder, D. J. Suson, A. Morselli, V. Vitale, M. Pepe, M. Brigida, F. Kuehn, Matthew Kerr, Y. Hanabata, P. L. Nolan, Brian L Winer, C. Meurer, J. Bregeon, C. Farnier, B. Giebels, I. A. Grenier, J. G. Thayer, M.-H. Grondin, Benjamin Stappers, A. A. Moiseev, A. Tramacere, A. P. Waite, Simon Johnston, Hiromitsu Takahashi, T. A. Porter, P. Wang, Gino Tosti, T. Glanzman, Richard N. Manchester, Takaaki Tanaka, T. L. Usher, R. E. Hughes, Emanuele Bonamente, G. Theureau, Margaret A. Livingstone, M. N. Mazziotta, A. A. Abdo, S. Germani, E. Hays, A. Y. Rodriguez, D. Parent, F. Loparco, Gloria Spandre, A. Bouvier, E. Orlando, G. Godfrey, Paulo C. C. Freire, T. Reposeur, Andrew Lyne, W. Mitthumsiri, D. Dumora, N. Kawai, A. W. Borgland, Hideaki Katagiri, Ismaël Cognard, P. Lubrano, T. Ylinen, D. J. Thompson, A. Reimer, Tyrel J. Johnson, James Chiang, Roger Blandford, A. Makeev, Johann Cohen-Tanugi, A. Van Etten, Igor V. Moskalenko, F. de Palma, A. De Angelis, Melissa Pesce-Rollins, R. Claus, M. S. Strickman, Olaf Reimer, M. Marelli, Nicola Omodei, M. Lemoine-Goumard, Claudia Cecchi, Michael Kramer, S. Murgia, B. Lott, M. E. Monzani, F. Piron, W. B. Atwood, Luca Baldini, M. Pierbattista, P. D. Smith, T. H. Burnett, S. Rainò, B. Berenji, Marco Ajello, J. B. Thayer, C. Favuzzi, J. M. Casandjian, Nicola Giglietto, Tsunefumi Mizuno, A. Chekhtman, M. Ziegler, K. Watters, Hartmut Sadrozinski, Gudlaugur Johannesson, E. Striani, Alice K. Harding, R. Dubois, L. Tibaldo, Charles D. Dermer, Felix Ryde, G. A. Caliandro, W. B. Focke, T. Ohsugi, M. N. Lovellette, S. Ritz, Hiroyasu Tajima, P. Spinelli, J. E. Grove, Guido Barbiellini, P. A. Caraveo, Persis S. Drell, Jan Conrad, Pascal Bruel, Y. Edmonds, Francesco Giordano, Yasushi Fukazawa, M. Frailis, L. S. Rochester, George Hobbs, C. C. Cheung, Keith Bechtol, Michael Keith, V. Vasileiou, Peter F. Michelson, Kent S. Wood, V. Pelassa, E. J. Siskind, Julie McEnery, Patrick Weltevrede, Neil Gehrels, Ronaldo Bellazzini, M. Razzano, J. H. Panetta, Diego F. Torres, Magnus Axelsson, N. Vilchez, David Sánchez, T. Kamae, Stephen E. Thorsett, Markus Ackermann, Luca Latronico, R. A. Cameron, Francesco Longo, Fernando Camilo, A. Sander, F. Gargano, Yasunobu Uchiyama, Roger W. Romani, E. Do Couto E Silva, Jean Ballet, Stefano Ciprini, Scott M. Ransom, Elliott D. Bloom, B. M. Baughman, Morihiro Hayashida, David S. Smith, Carmelo Sgrò, Riccardo Rando, E. Nuss, David Paneque, M. Kuss, Jonathan F. Ormes, Cristobal M. Espinoza, L. Guillemot, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie de l'environnement (LPCE), Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Abdo, A. A., Ackermann, M., Ajello, M., Atwood, W. B., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Caliandro, G. A., Cameron, R. A., Camilo, F., Caraveo, P. A., Casandjian, J. M., Cecchi, C., Celik, O., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cognard, I., Cohen Tanugi, J., Conrad, J., Dermer, C. D., Angelis, A. d., Palma, F. d., Digel, S. W., Dormody, M., Silva, E. D. E., Drell, P. S., Dubois, R., Dumora, D., Edmonds, Y., Espinoza, C., Farnier, C., Favuzzi, C., Focke, W. B., Frailis, M., Freire, P. C. C., Fukazawa, Y., Fusco, P., Gargano, F., Gehrels, N., Germani, S., Giebels, B., Giglietto, N., Giordano, F., Glanzman, T., Godfrey, G., Grenier, I. A., Grondin, M. H., Grove, J. E., Guillemot, L., Guiriec, S., Hanabata, Y., Harding, A. K., Hayashida, M., Hays, E., Hobbs, G., Hughes, R. E., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, T. J., Johnson, W. N., Johnston, S., Kamae, T., Kaspi, V. M., Katagiri, H., Kataoka, J., Kawai, N., Keith, M., Kerr, M., Knodlseder, J., Kramer, M., Kuehn, F., Kuss, M., Lande, J., Latronico, L., Lemoine Goumard, M., Livingstone, M., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Lyne, A. G., Makeev, A., Manchester, R. N., Marelli, M., Mazziotta, M. N., Mcenery, J. E., Meurer, C., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nolan, P. L., Nuss, E., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce Rollins, M., Pierbattista, M., Piron, F., Porter, T. A., Raino, S., Rando, R., Ransom, S. M., Razzano, M., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Rochester, L. S., Rodriguez, A. Y., Romani, R. W., Ryde, F., Sadrozinski, H. F. W., Sanchez, D., Sander, A., Parkinson, P. M. S., Sgro, C., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Stappers, B. W., Striani, E., Strickman, M. S., Suson, D. J., Tajima, H., Takahashi, H., Tanaka, T., Thayer, J. B., Thayer, J. G., Theureau, G., Thompson, D. J., Thorsett, S. E., Tibaldo, L., Torres, D. F., Tosti, G., Tramacere, A., Uchiyama, Y., Usher, T. L., Etten, A. V., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wang, P., Watters, K., Weltevrede, P., Winer, B. L., Wood, K. S., Ylinen, T., Ziegler, M., Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Fermi satellite, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, High Energy Gamma-ray Astronomy, Luminosity, law.invention, Telescope, stars: neutron, Spitzer Space Telescope, Pulsar, law, pulsars: general, 0103 physical sciences, Supernova remnant, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Pulsars, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Green Bank Telescope, Astronomy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Neutron star, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), High Energy Physics::Experiment, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract

We report the discovery of gamma-ray pulsations (> 0.1 GeV) from the young radio and X-ray pulsar PSR J0205+6449 located in the Galactic supernova remnant 3C 58. Data in the gamma-ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (formerly GLAST), while the radio rotational ephemeris used to fold gamma-rays was obtained using both the Green Bank Telescope and the Lovell telescope at Jodrell Bank. The light curve consists of two peaks separated by 0.49 +/- 0.01 +/- 0.01 cycles which are aligned with the X-ray peaks. The first gamma-ray peak trails the radio pulse by 0.08 +/- 0.01 +/- 0.01, while its amplitude decreases with increasing energy as for the other gamma-ray pulsars. Spectral analysis of the pulsed gamma-ray emission suggests a simple power law of index -2.1 +/- 0.1 +/- 0.2 with an exponential cut-off at 3.0 +1.1 -0.7 +/- 0.4 GeV. The first uncertainty is statistical and the second is systematic. The integral gamma-ray photon flux above 0.1 GeV is (13.7 +/- 1.4 +/- 3.0) x 10^(-8) /cm2/s, which implies for a distance of 3.2 kpc and assuming a broad fan-like beam a luminosity of 8.3 x 10^(34) ergs/s and an efficiency eta of 0.3%. Finally, we report a 95% upper limit on the flux of 1.7 x 10^(-8) /cm2/s for off-pulse emission from the object., 7 pages, 1 figure, accepted for publication in Astrophysical Journal Letters, contact author: Damien Parent

Published
2009
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15. First AGILE catalog of high-confidence gamma-ray sources

Author

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

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

We present the first catalog of high-confidence gamma-ray sources detected by the AGILE satellite during observations performed from July 9, 2007 to June 30, 2008. Catalogued sources are detected by merging all the available data over the entire time period. AGILE, launched in April 2007, is an ASI mission devoted to gamma-ray observations in the 30 MeV - 50 GeV energy range, with simultaneous X-ray imaging capability in the 18-60 keV band. This catalog is based on Gamma-Ray Imaging Detector (GRID) data for energies greater than 100 MeV. For the first AGILE catalog we adopted a conservative analysis, with a high-quality event filter optimized to select gamma-ray events within the central zone of the instrument Field of View (radius of 40 degrees). This is a significance-limited (4 sigma) catalog, and it is not a complete flux-limited sample due to the non-uniform first year AGILE sky coverage. The catalog includes 47 sources, 21 of which are associated with confirmed or candidate pulsars, 13 with Blazars (7 FSRQ, 4 BL Lacs, 2 unknown type), 2 with HMXRBs, 2 with SNRs, 1 with a colliding-wind binary system, 8 with unidentified sources., Revised version, 15 pages, 3 figures, 3 tables. To be published in Astronomy and Astrophysics. Text improved and clarified. Refined analysis of complex regions of the Galactic plane yields a new list of high-confidence sources including 47 sources (compared with the 40 sources appearing in the first version)

Published
2009

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

Author

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

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

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

Published
2009

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

Author

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

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Vela, Pulsar wind nebula, High Energy Gamma-ray Astronomy, gamma detection, Relativistic particle, AGILE, Pulsar Wind Nebulae, Pulsar, Astrophysics::Solar and Stellar Astrophysics, AGILE satellite, education, Astrophysics::Galaxy Astrophysics, pulsar, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, Multidisciplinary, Vela Pulsar Wind Nebula, AGILE, gamma-rays, Gamma ray, Astronomy, Physics::Space Physics, Astrophysics - High Energy Astrophysical Phenomena, Phenomenology (particle physics), X-ray pulsar
Abstract

Pulsars are known to power winds of relativistic particles that can produce bright nebulae by interacting with the surrounding medium. These pulsar wind nebulae (PWNe) are observed in the radio, optical, x-rays and, in some cases, also at TeV energies, but the lack of information in the gamma-ray band prevents from drawing a comprehensive multiwavelength picture of their phenomenology and emission mechanisms. Using data from the AGILE satellite, we detected the Vela pulsar wind nebula in the energy range from 100 MeV to 3 GeV. This result constrains the particle population responsible for the GeV emission, probing multivavelength PWN models, and establishes a class of gamma-ray emitters that could account for a fraction of the unidentified Galactic gamma-ray sources., Comment: Accepted by Science; first published online on December 31, 2009 in Science Express. Science article and Supporting Online Material are available at http://www.sciencemag.org

Published
2009
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18. AGILE detection of GeV $\sf$γ-ray emission from the SNR W28

Author

A. Giuliani, M. Tavani, A. Bulgarelli, E. Striani, S. Sabatini, M. Cardillo, Y. Fukui, A. Kawamura, A. Ohama, N. Furukawa, K. Torii, H. Sano, F. A. Aharonian, F. Verrecchia, A. Argan, G. Barbiellini, P. A. Caraveo, P. W. Cattaneo, A. W. Chen, V. Cocco, E. Costa, F. D'Ammando, E. Del Monte, G. De Paris, G. Di Cocco, I. Donnarumma, Y. Evangelista, M. Feroci, M. Fiorini, T. Froysland, F. Fuschino, M. Galli, F. Gianotti, C. Labanti, Y. Lapshov, F. Lazzarotto, P. Lipari, F. Longo, M. Marisaldi, S. Mereghetti, A. Morselli, E. Moretti, L. Pacciani, A. Pellizzoni, F. Perotti, P. Picozza, M. Pilia, M. Prest, G. Pucella, M. Rapisarda, A. Rappoldi, P. Soffitta, M. Trifoglio, A. Trois, E. Vallazza, S. Vercellone, V. Vittorini, A. Zambra, D. Zanello, C. Pittori, P. Santolamazza, P. Giommi, S. Colafrancesco, L. Salotti, A., Giuliani, M., Tavani, A., Bulgarelli, E., Striani, S., Sabatini, M., Cardillo, Y., Fukui, A., Kawamura, A., Ohama, N., Furukawa, K., Torii, H., Sano, F. A., Aharonian, F., Verrecchia, A., Argan, G., Barbiellini, P. A., Caraveo, P. W., Cattaneo, A. W., Chen, V., Cocco, E., Costa, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, I., Donnarumma, Y., Evangelista, M., Feroci, M., Fiorini, T., Froysland, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, Y., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, A., Morselli, E., Moretti, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, P., Santolamazza, P., Giommi, S., Colafrancesco, L., Salotti, Giuliani A, Tavani M, Bulgarelli A, Striani E, Sabatini S, Cardillo M, Fukui Y, Kawamura A, Ohama A, Furukawa N, Torii K, Sano H, Aharonian FA, Verrecchia F, Argan A, Barbiellini G, Caraveo PA, Cattaneo PW, Chen AW, Cocco V, Costa E, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Donnarumma I, Evangelista Y, Feroci M, Fiorini M, Froysland T, Fuschino F, Galli M, Gianotti F, Labanti C, Lapshov Y, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mereghetti S, Morselli A, Moretti E, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Pilia M, Prest M, Pucella G, Rapisarda M, Rappoldi A, Soffitta P, Trifoglio M, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Santolamazza P, Giommi P, Colafrancesco S, and Salotti L

Subjects
Supernova Remnants, Supernova, Astrophysics::High Energy Astrophysical Phenomena, Hadron, acceleration of particles – diffusion – ISM: supernova remnants – gamma rays: ISM, FOS: Physical sciences, Flux, Cosmic ray, Astrophysics, AGILE, galactic cosmic rays, High Energy Gamma-ray Astronomy, Spectral line, law.invention, Telescope, law, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Molecular cloud, AGILE satellite, Gamma ray, Astronomy and Astrophysics, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Supernova remnants (SNRs) are believed to be the main sources of Galactic cosmic rays. Molecular clouds associated with SNRs can produce gamma-ray emission through the interaction of accelerated particles with the concentrated gas. The middle aged SNR W28, for its associated system of dense molecular clouds, provides an excellent opportunity to test this hypothesis. We present the AGILE/GRID observations of SNR W28, and compare them with observations at other wavelengths (TeV and 12CO J=1-->0 molecular line emission). The gamma-ray flux detected by AGILE from the dominant source associated with W28 is (14 +- 5) 10^-8 ph cm^-2 s^-1 for E > 400 MeV. This source is positionally well correlated with the TeV emission observed by the HESS telescope. The local variations of the GeV to TeV flux ratio suggest a difference between the CR spectra of the north-west and south molecular cloud complexes. A model based on a hadronic-induced interaction and diffusion with two molecular clouds at different distances from the W28 shell can explain both the morphological and spectral features observed by AGILE in the MeV-GeV energy range and by the HESS telescope in the TeV energy range. The combined set of AGILE and H.E.S.S. data strongly support a hadronic model for the gamma-ray production in W28., Accepted for publication in Astronomy & Astrophysics Letters

Published
2010
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