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Start Over Author "Salotti, L." Topic astrophysics - high energy astrophysical phenomena
46 results on '"Salotti, L."'

1. The Agile Alert System For Gamma-Ray Transients

Author

Bulgarelli, A., Trifoglio, M., Gianotti, F., Tavani, M., Parmiggiani, N., Fioretti, V., Chen, A. W., Vercellone, S., Pittori, C., Verrecchia, F., Lucarelli, F., Santolamazza, P., Fanari, G., Giommi, P., Beneventano, D., Argan, A., Trois, A., Scalise, E., Longo, F., Pellizzoni, A., Pucella, G., Colafrancesco, S., Conforti, V., Tempesta, P., Cerone, M., Sabatini, P., Annoni, G., Valentini, G., and Salotti, L.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

In recent years, a new generation of space missions offered great opportunities of discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) onboard the AGILE space mission. The AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many gamma-ray transients of galactic and extragalactic origins. This work presents the AGILE innovative approach to fast gamma-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe: (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for gamma-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, e-mails, and push notifications of an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in gamma-ray astrophysics., Comment: 34 pages, 9 figures, 5 tables

Published
2014
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2. 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., and Valentini, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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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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., and Valentini, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, 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
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4. Galactic Sources Science With Agile: The Case Of The Carina Region

Author

Sabatini, S., Tavani, M., Pian, E., Bulgarelli, A., Caraveo, P., Viotti, R., Corcoran, M. F., Giuliani, A., Pittori, C., Verrecchia, F., Vercellone, S., Mereghetti, S., Argan, A., Barbiellini, G., Boffelli, F., Cattaneo, P. W., Chen, A. W., Cocco, V., D'Ammando, F., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Marisaldi, M., Mastropietro, M., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Pucella, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Vittorini, V., Zambra, A., Zanello, D., Santolamazza, P., Giommi, P., Colafrancesco, S., Antonelli, L. A., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

During its first 2 years of operation, the gamma-ray AGILE satellite accumulated an extensive dataset for the Galactic plane. The data have been monitored for transient sources and several gamma-ray sources were detected. Their variability and possible association were studied. In this talk we will focus on the results of extensive observations of the Carina Region during the time period 2007 July - 2009 January, for a total livetime of ~130 days. The region is extremely complex, hosting massive star formation, with the remarkable colliding wind binary Eta Carinae, massive star clusters and HII regions (e.g. NGC 3324, RCW49, Westerlund II) and a giant molecular cloud extending over 150 pc (between l=284.7 and l=289). The Carina Nebula itself is the largest and IR highest surface brightness nebula of the Southern emisphere. We monitored several gamma ray sources in the Carina Region. In particular we detect a gamma ray source (1AGL J1043-5931) consistent with the position of Eta Carinae and report a remarkable 2-days gamma-ray flaring episode from this source on 2008 Oct 11-13. If 1AGL J1043-5931 is associated with the Eta Car system, our data provides the long sought first detection above 100 MeV of a colliding wind binary., Comment: 5 pages, 5 figures, proceedings of RICAP 2009

Published
2012
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5. The flaring blazars of the first 1.5 years of the AGILE mission

Author

Pacciani, L., Bulgarelli, A., Chen, A. W., D'Ammando, F., Donnarumma, I., Giuliani, A., Longo, F., Pucella, G., Tavani, M., Vercellone, S., Vittorini, V., Argan, A., Barbiellini, G., Boffelli, F., Caraveo, P., Cattaneo, P. W., Cocco, V., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Froysland, T., 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., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Antonelli, L. A., Colafrancesco, S., Giommi, P., Pittori, C., Verrecchia, F., Santolamazza, P., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the AGILE gamma-ray observations and the results of the multiwavelength campaigns on seven flaring blazars detected by the mission: During two multiwavelength campaigns, we observed gamma-ray activity from two Flat Spectrum Radio Quasars of the Virgo region, e.g. 3C 279 and 3C 273 (the latter being the first extragalactic source simultaneously observed with the gamma-ray telescope and the hard X ray imager of the mission). Due to the large FOV of the AGILE/GRID instrument, we achieved an almost continuous coverage of the FSRQ 3C 454.3. The source showed flux above 10E-6 photons/cm2/s (E > 100 MeV) and showed day by day variability during all the AGILE observing periods. In the EGRET era, the source was found in high gamma-ray activity only once. An other blazar, PKS 1510-089 was frequently found in high gamma-ray activity. S5 0716+71, an intermediate BL Lac object, exhibited a very high gamma-ray activity and fast gamma-ray variability during a period of intense optical activity. We observed high gamma-ray activity from W Comae, a BL Lac object, and Mrk 421, an high energy peaked BL Lac object. For this source, a multiwavelength campaign from optical to TeV has been performed.

Published
2011
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6. 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., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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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7. 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., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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

Published
2011
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8. 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., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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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9. 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., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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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10. Discovery of Powerful Gamma-Ray Flares from the Crab Nebula

Author

Tavani, M., Bulgarelli, A., Vittorini, V., Pellizzoni, A., Striani, E., Caraveo, P., Weisskopf, 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.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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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11. Study of the gamma-ray source 1AGL J2022+4032 in the Cygnus Region

Author

Chen, A. W., Piano, G., Tavani, M., Trois, A., Dubner, G., Giacani, E., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Costa, E., D'Ammando, 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, L. A., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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., Comment: 7 pages, 7 figures, accepted for publication in Astronomy & Astrophysics

Published
2010
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12. Agile Observations of the 'Soft' Gamma-Ray Pulsar PSR B1509-58

Author

Pilia, M., Pellizzoni, A., Trois, A., Verrecchia, F., Esposito, P., Weltevrede, P., Johnston, S., Burgay, M., Possenti, A., Del Monte, E., Fuschino, F., Santolamazza, P., Chen, A., Giuliani, A., Caraveo, P., Mereghetti, S., Tavani, M., Argan, A., Costa, E., D'Amico, N., De Luca, A., Evangelista, Y., Feroci, M., Longo, F., Marisaldi, M., Barbiellini, G., Bulgarelli, A., Cattaneo, P. W., Cocco, V., D'Ammando, F., De Paris, G., Di Cocco, G., Donnarumma, I., Fiorini, M., Froysland, T., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Prest, M., Pucella, G., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Vallazza, E., Vercellone, S., Vittorini, V., Zambra, A., Zanello, D., Pittori, C., Lucarelli, F., Giommi, P., Salotti, L., and Bignami, G. F.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the results of new Agile observations of PSR B1509-58 performed over a period of 2.5 years following the detection obtained with a subset of the present data. The modulation significance of the lightcurve above 30 MeV is at a 5$\sigma$ confidence level and the lightcurve is similar to those found earlier by Comptel up to 30 MeV: a broad asymmetric first peak reaching its maximum 0.39 +/- 0.02 cycles after the radio peak plus a second peak at 0.94 +/- 0.03. The gamma-ray spectral energy distribution of the pulsed flux detected by Comptel and Agile is well described by a power-law (photon index alpha=1.87+/-0.09) with a remarkable cutoff at E_c=81 +/- 20 MeV, representing the softest spectrum observed among gamma-ray pulsars so far. The pulsar luminosity at E > 1 MeV is $L_{\gamma}=4.2^{+0.5}_{-0.2} \times10^{35}$ erg/s, assuming a distance of 5.2 kpc, which implies a spin-down conversion efficiency to gamma-rays of $\sim 0.03$. The unusual soft break in the spectrum of PSR B1509-58 has been interpreted in the framework of polar cap models as a signature of the exotic photon splitting process in the strong magnetic field of this pulsar. In this interpretation our spectrum constrains the magnetic altitude of the emission point(s) at 3 km above the neutron star surface, implying that the attenuation may not be as strong as formerly suggested because pair production can substitute photon splitting in regions of the magnetosphere where the magnetic field becomes too low to sustain photon splitting. In the case of an outer-gap scenario, or the two pole caustic model, better constraints on the geometry of the emission would be needed from the radio band in order to establish whether the conditions required by the models to reproduce Agile lightcurves and spectra match the polarization measurements., Comment: 17 pages, 2 figures, accepted for publication in ApJ

Published
2010
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13. AGILE detection of GeV gamma-ray emission from the SNR W28

Author

Giuliani, A., Tavani, M., Bulgarelli, A., Striani, E., Sabatini, S., Cardillo, M., Fukui, Y., Kawamura, A., Ohama, A., Furukawa, N., Torii, K., Aharonian, F. A., Verrecchia, F., Argan, A., Barbiellini, G., Caraveo, P. A., Cattaneo, P. W., Chen, A. W., Cocco, V., Costa, E., D'Ammando, 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., Mereghetti, M. Marisaldi., 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
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., Comment: Accepted for publication in Astronomy & Astrophysics Letters

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

Author

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, P. W., Chen, A., D'Ammando, 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, L. A., Cutini, S., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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
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15. Episodic Transient Gamma-Ray Emission from the Microquasar Cygnus X-1

Author

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, P. W., Chen, A. W., D'Ammando, 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, L. A., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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
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16. 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., Boettcher, 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., and Nilsson, K.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on 18 months of multiwavelength observations of the blazar 3C 454.3 (Crazy Diamond) carried out in July 2007-January 2009. We show the results of the AGILE campaigns which took place on May-June 2008, July-August 2008, and October 2008-January 2009. During the May 2008-January 2009 period, the source average flux was highly variable, from an average gamma-ray flux F(E>100MeV) > 200E-8 ph/cm2/s in May-June 2008, to F(E>100MeV)~80E-8 ph/cm2/s in October 2008-January 2009. The average gamma-ray spectrum between 100 MeV and 1 GeV can be fit by a simple power law (Gamma_GRID ~ 2.0 to 2.2). Only 3-sigma upper limits can be derived in the 20-60 keV energy band with Super-AGILE. During July-August 2007 and May-June 2008, RXTE measured a flux of F(3-20 keV)= 8.4E-11 erg/cm2/s, and F(3-20 keV)=4.5E-11 erg/cm2/s, respectively and a constant photon index Gamma_PCA=1.65. Swift/XRT observations were carried out during all AGILE campaigns, obtaining a F(2-10 keV)=(0.9-7.5)E-11 erg/cm2/s and a photon index Gamma_XRT=1.33-2.04. BAT measured an average flux of ~5 mCrab. GASP-WEBT monitored 3C 454.3 during the whole 2007-2008 period from the radio to the optical. A correlation analysis between the optical and the gamma-ray fluxes shows a time lag of tau=-0.4 days. An analysis of 15 GHz and 43 GHz VLBI core radio flux observations shows an increasing trend of the core radio flux, anti- correlated with the higher frequency data. The modeling SEDs, and the behavior of the long-term light curves in different energy bands, allow us to compare the jet properties during different emission states, and to study the geometrical properties of the jet on a time-span longer than one year., Comment: Accepted for publication in ApJ. Adapted Abstract. 17 pages, 19 Figures, 5 Tables

Published
2010
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17. Direct Evidence for Hadronic Cosmic-Ray Acceleration in the Supernova Renmant IC 443

Author

Tavani, M., Giuliani, A., Chen, A. W., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Cocco, V., Contessi, T., D'Ammando, 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, L. A., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
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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18. 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, E., Morselli, A., Pacciani, L., Palfreyman, J., Perotti, F., Picozza, P., Pittori, C., Possenti, A., Prest, M., Rapisarda, M., Rappoldi, A., Rossi, E., Rubini, A., Santolamazza, P., Scalise, E., Soffitta, P., Striani, E., Trifoglio, M., Vallazza, E., Vercellone, S., Verrecchia, F., Vittorini, V., Zambra, A., Zanello, D., Giommi, P., Colafrancesco, S., Antonelli, A., Salotti, L., D'Amico, N., and Bignami, G. F.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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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19. Temporal properties of GX 301-2 over a year-long observation with SuperAGILE

Author

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, P. W., Chen, A., D'Ammando, 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, L. A., Cutini, S., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
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., Comment: 10 pages, 7 figures, 3 tables, accepted for publication in ApJ

Published
2009
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20. 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
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., Comment: 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
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21. Multiwavelength observations of 3C 454.3 II. The AGILE 2007 December campaign

Author

Donnarumma, I., Pucella, G., Vittorini, V., D'Ammando, F., Vercellone, S., Raiteri, C. M., Villata, M., Perri, M., Chen, W. P., Smart, R. L., Kataoka, J., Kawai, N., Mori, Y., Tosti, G., Impiombato, D., Takahashi, T., Sato, R., Tavani, M., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Pacciani, L., Argan, A., Barbiellini, G., Boffelli, F., Caraveo, P., Cattaneo, P. W., 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., 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, L. A., Colafrancesco, S., and Salotti, L.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on the second AGILE multiwavelength campaign of the blazar 3C 454.3 during the first half of December 2007. This campaign involved AGILE, Spitzer, Swift,Suzaku,the WEBT consortium,the REM and MITSuME telescopes,offering a broad band coverage that allowed for a simultaneous sampling of the synchrotron and inverse Compton (IC) emissions.The 2-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~250x10^{-8}ph cm^-2s^-1 above 100 MeV,typical of its flaring states.The simultaneous optical and gamma-ray monitoring allowed us to study the time-lag associated with the variability in the two energy bands, resulting in a possible ~1-day delay of the gamma-ray emission with respect to the optical one. From the simultaneous optical and gamma-ray fast flare detected on December 12, we can constrain the delay between the gamma-ray and optical emissions within 12 hours. Moreover, we obtain three Spectral Energy Distributions (SEDs) with simultaneous data for 2007 December 5, 13, 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=10^6 K surrounding the jet, is required to account simultaneously for the softness of the synchrotron and the hardness of the inverse Compton emissions during those epochs., Comment: 13 pages, 8 figures, 2 tables, Accepted for publication in ApJ

Published
2009
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22. Monitoring the hard X-ray sky with SuperAGILE

Author

Feroci, M., Costa, E., Del Monte, E., Donnarumma, I., Evangelista, Y., Lapshov, I., Lazzarotto, F., Pacciani, L., Rapisarda, M., Soffitta, P., Di Persio, G., Frutti, M., Mastropietro, M., Morelli, E., Porrovecchio, G., Rubini, A., Antonelli, A., Argan, A., Barbiellini, G., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A. W., Cocco, V., Colafrancesco, S., Cutini, S., D'Ammando, F., De Paris, G., Di Cocco, G., Fanari, G., Ferrari, A., Fiorini, M., Fornari, F., Fuschino, F., Froysland, T., Galli, M., Gasparrini, D., Gianotti, F., Giommi, P., Giuliani, A., Labanti, C., Liello, F., Lipari, P., Longo, F., Mattaini, E., Marisaldi, M., Mauri, A., Mauri, F., Mereghetti, S., Moretti, E., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Pittori, C., Pontoni, C., Preger, B., Prest, M., Primavera, R., Pucella, G., Rappoldi, A., Rossi, E., Sabatini, S., Santolamazza, P., Tavani, M., Stellato, S., Tamburelli, F., Traci, A., Trifoglio, M., Trois, A., Vallazza, E., Vercellone, S., Verrecchia, F., Vittorini, V., Zambra, A., Zanello, D., and Salotti, L.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

SuperAGILE is the hard X-ray monitor of the AGILE gamma ray mission, in orbit since 23$^{rd}$ April 2007. It is an imaging experiment based on a set of four independent silicon strip detectors, equipped with one-dimensional coded masks, operating in the nominal energy range 18-60 keV. The main goal of SuperAGILE is the observation of cosmic sources simultaneously with the main gamma-ray AGILE experiment, the Gamma Ray Imaging Detector (GRID). Given its $\sim$steradian-wide field of view and its $\sim$15 mCrab day-sensitivity, SuperAGILE is also well suited for the long-term monitoring of Galactic compact objects and the detection of bright transients. The SuperAGILE detector properties and design allow for a 6 arcmin angular resolution in each of the two independent orthogonal projections of the celestial coordinates. Photon by photon data are continuously available by the experiment telemetry, and are used to derive images and fluxes of individual sources, with integration times depending on the source intensity and position in the field of view. In this paper we report on the main scientific results achieved by SuperAGILE over its first two years in orbit, until April 2009., Comment: Accepted for publication on Astronomy & Astrophysics

Published
2009
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23. Multiwavelength observations of a TeV-Flare from W Comae

Author

VERITAS collaboration, Acciari, V. A., Aliu, E., Aune, T., Beilicke, M., Benbow, W., Bottcher, M., Boltuch, D., Buckley, J. H., Bradbury, S. M., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Duke, C., Falcone, A., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Sembroski, G. H., Smith, A. W., Steele, D., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Team, The AGILE, Pian, E., Vercellone, S., Donnarumma, I., D'Ammando, F., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Pacciani, L., Pucella, G., Vittorini, V., Tavani, M., Argan, A., Barbiellini, G., Caraveo, P., Cattaneo, P. W., Cocco, V., Costa, E., Del Monte, E., De Paris, G., Di Cocco, G., Evangelista, Y., Feroci, M., 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., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Soffitta, S. Sabatini P., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., Colafrancesco, S., Salotti, L., Villata, M., Raiteri, C. M., Aller, H. D., Aller, M. F., Arkharov, A. A., Efimova, N. V., Larionov, V. M., Leto, P., Ligustri, R., Lindfors, E., Pasanen, M., Kurtanidze, O. M., Tetradze, S. D., Lahteenmaki, A., Kotiranta, M., Cucchiara, A., Romano, P., Nesci, R., Pursimo, T., Heidt, J., Benitez, E., Hiriart, D., Nilsson, K., Berdyugin, A., Mujica, R., Dultzin, D., Lopez, J. M., Mommert, M., Sorcia, M., and Perez, I. de la Calle

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report results from an intensive multiwavelength campaign on the intermediate-frequency-peaked BL Lacertae object W Com (z=0.102) during a strong outburst of very high energy gamma-ray emission in June 2008. The very high energy gamma-ray signal was detected by VERITAS on 2008 June 7-8 with a flux F(>200 GeV) = (5.7+-0.6)x10^-11 cm-2s-1, about three times brighter than during the discovery of gamma-ray emission from W Com by VERITAS in 2008 March. The initial detection of this flare by VERITAS at energies above 200 GeV was followed by observations in high energy gamma-rays (AGILE, E>100 MeV), and X-rays (Swift and XMM-Newton), and at UV, and ground-based optical and radio monitoring through the GASP-WEBT consortium and other observatories. Here we describe the multiwavelength data and derive the spectral energy distribution (SED) of the source from contemporaneous data taken throughout the flare., Comment: 26 pages, 5 figures; Accepted for publication by The Astrophysical Journal

Published
2009
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24. AGILE detection of a rapid gamma-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

Author

D'Ammando, F., Pucella, G., Raiteri, C. M., Villata, M., Vittorini, V., Vercellone, S., Donnarumma, I., Longo, F., 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., Fuschino, F., Galli, M., Gianotti, F., Giuliani, A., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Marisaldi, M., Mereghetti, S., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Prest, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Agudo, I., Aller, M. F., Aller, H. D., Arkharov, A. A., Bach, U., Benitez, E., Berdyugin, A., Blinov, D. A., Buemi, C. S., Chen, W. P., Di Paola, A., Di Rico, G., Dultzin, D., Fuhrmann, L., Gomez, J. L., Gurwell, M. A., Jorstad, S. G., Heidt, J., Hiriart, D., Hsiao, H. Y., Kimeridze, G., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O., Larionov, V. M., Leto, P., Lindfors, E., Lopez, J. M., Marscher, A. P., McHardy, I. M., Melnichuk, D. A., Mommert, M., Mujica, R., Nilsson, K., Pasanen, M., Roca-Sogorb, M., Sorcia, M., Takalo, L. O., Taylor, B., Trigilio, C., Troitsky, I. S., Umana, G., Antonelli, L. A., Colafrancesco, S., Cutini, S., Gasparrini, D., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Giommi, P., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report the detection by the AGILE satellite of a rapid gamma-ray flare from the powerful gamma-ray quasar PKS 1510-089, during a pointing centered on the Galactic Center region from 1 March to 30 March 2008. This source has been continuosly monitored in the radio-to-optical bands by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT). Moreover, the gamma-ray flaring episode triggered three ToO observations by the Swift satellite in three consecutive days, starting from 20 March 2008. In the period 1-16 March 2008, AGILE detected gamma-ray emission from PKS 1510-089 at a significance level of 6.2-sigma with an average flux over the entire period of (84 +/- 17) x 10^{-8} photons cm^{-2} s^{-1} for photon energies above 100 MeV. After a predefined satellite re-pointing, between 17 and 21 March 2008, AGILE detected the source at a significance level of 7.3-sigma, with an average flux (E > 100 MeV) of (134 +/- 29) x 10^{-8} photons cm^{-2} s^{-1} and a peak level of (281 +/- 68) x 10^{-8} photons cm^{-2} s^{-1} with daily integration. During the observing period January-April 2008, the source also showed an intense and variable optical activity, with several flaring episodes and a significant increase of the flux was observed at millimetric frequencies. Moreover, in the X-ray band the Swift/XRT observations seem to show an harder-when-brighter behaviour of the source spectrum. The spectral energy distribution of mid-March 2008 is modelled with a homogeneous one-zone synchrotron self Compton emission plus contributions from inverse Compton scattering of external photons from both the accretion disc and the broad line region. Indeed, some features in the optical-UV spectrum seem to indicate the presence of Seyfert-like components, such as the little blue bump and the big blue bump., Comment: 10 pages, 4 figures and 2 tables, accepted for publication in A&A

Published
2009
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25. Agile Detection of Delayed Gamma-Ray Emission from the Short Gamma-Ray Burst GRB 090510

Author

Giuliani, A., Fuschino, F., Vianello, G., Marisaldi, M., Mereghetti, S., Tavani, M., Cutini, S., Barbiellini, G., Longo, F., Moretti, E., Feroci, M., Del Monte, E., Argan, A., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A. W., Contessi, T., D'Ammando, F., Costa, E., De Paris, G., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Fiorini, M., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Pucella, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Sabatini, S., Scalise, E., 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, L. A., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Short gamma-ray bursts (GRBs), typically lasting less than 2 s, are a special class of GRBs of great interest. We report the detection by the AGILE satellite of the short GRB 090510 which shows two clearly distinct emission phases: a prompt phase lasting ~ 200 msec and a second phase lasting tens of seconds. The prompt phase is relatively intense in the 0.3-10 MeV range with a spectrum characterized by a large peak/cutoff energy near 3 MeV, in this phase, no significant high-energy gamma-ray emission is detected. At the end of the prompt phase, intense gamma-ray emission above 30 MeV is detected showing a power-law time decay of the flux of the type t^-1.3 and a broad-band spectrum remarkably different from that of the prompt phase. It extends from sub-MeV to hundreds of MeV energies with a photon index alpha ~ 1.5. GRB 090510 provides the first case of a short GRB with delayed gamma-ray emission. We present the timing and spectral data of GRB 090510 and briefly discuss its remarkable properties within the current models of gamma-ray emission of short GRBs., Comment: Accepted by the Astrophysical Journal Letters on September 11, 2009

Published
2009
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26. Detection of Gamma-ray Emission from the Eta-Carinae Region

Author

Tavani, M., Sabatini, S., Pian, E., Bulgarelli, A., Caraveo, P., Viotti, R. F., Corcoran, M. F., Giuliani, A., Pittori, C., Verrecchia, F., Vercellone, S., Mereghetti, S., Argan, A., Barbiellini, G., Boffelli, F., Cattaneo, P. W., Chen, A. W., Cocco, V., D'Ammando, F., Costa, E., De Paris, G., Del Monte, E., Di Cocco, G., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., Fiorini, M., Froysland, T., Fuschino, F., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Longo, F., Marisaldi, M., Mastropietro, M., Morelli, E., Moretti, E., Morselli, A., Pacciani, L., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Pucella, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Soffitta, P., Trifoglio, M., Trois, A., Vallazza, E., Vittorini, V., Zambra, A., Zanello, D., Santolamazza, P., Giommi, P., Colafrancesco, S., Antonelli, L. A., and Salotti, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the results of extensive observations by the gamma-ray AGILE satellite of the Galactic region hosting the Carina nebula and the remarkable colliding wind binary Eta Carinae (Eta Car) during the period 2007 July to 2009 January. We detect a gamma-ray source (1AGL J1043-5931) consistent with the position of Eta Car. If 1AGL J1043-5931 is associated with the Eta Car system our data provide the long sought first detection above 100 MeV of a colliding wind binary. The average gamma-ray flux above 100 MeV and integrated over the pre-periastron period 2007 July to 2008 October is F = (37 +/- 5) x 10-8 ph cm-2 s-1 corresponding to an average gamma-ray luminosity of L = 3.4 x 10^34 erg s-1 for a distance of 2.3 kpc. We also report a 2-day gamma-ray flaring episode of 1AGL J1043-5931 on 2008 Oct. 11-13 possibly related to a transient acceleration and radiation episode of the strongly variable shock in the system., Comment: 5 pages, 4 figure, accepted for publication in ApJ Letters

Published
2009
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27. Discovery of new gamma-ray pulsars with AGILE

Author

Pellizzoni, A., Pilia, M., Possenti, A., Chen, A., Giuliani, A., Trois, A., Caraveo, P., Del Monte, E., Fornari, F., Fuschino, F., Mereghetti, S., Tavani, M., Argan, A., Burgay, M., Cognard, I., Corongiu, A., Costa, E., D'Amico, N., De Luca, A., Esposito, P., Evangelista, Y., Feroci, M., Johnston, S., Kramer, M., Longo, F., Marisaldi, M., Theureau, G., Weltevrede, P., Barbiellini, G., Boffelli, F., Bulgarelli, A., Cattaneo, P. W., Cocco, V., D'Ammando, F., De Paris, G., Di Cocco, G., Donnarumma, I., Fiorini, M., Froysland, T., Galli, M., Gianotti, F., Labanti, C., Lapshov, I., Lazzarotto, F., Lipari, P., Mineo, T., Morselli, A., Pacciani, L., Perotti, F., Piano, G., Picozza, P., Prest, M., Pucella, G., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Vallazza, E., Vercellone, S., Vittorini, V., Zambra, A., Zanello, D., Pittori, C., Verrecchia, F., Preger, B., Santolamazza, P., Giommi, P., Salotti, L., and Bignami, G. F.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Using gamma-ray data collected by the Astrorivelatore Gamma ad Immagini LEggero (AGILE) satellite over a period of almost one year (from 2007 July to 2008 June), we searched for pulsed signals from 35 potentially interesting radio pulsars, ordered according to $F_{\gamma}\propto \sqrt{\dot{E}} d^{-2}$ and for which contemporary or recent radio data were available. AGILE detected three new top-ranking nearby and Vela-like pulsars with good confidence both through timing and spatial analysis. Among the newcomers we find pulsars with very high rotational energy losses, such as the remarkable PSR B1509-58 with a magnetic field in excess of 10^13 Gauss, and PSR J2229+6114 providing a reliable identification for the previously unidentified EGRET source 3EG 2227+6122. Moreover, the powerful millisecond pulsar B1821-24, in the globular cluster M28, is detected during a fraction of the observations. Four other promising gamma-ray pulsar candidates, among which is the notable J2043+2740 with an age in excess of 1 million years, show a possible detection in the timing analysis only and deserve confirmation., Comment: Minor changes to match the final ApJ version. 5 pages in emulate-apj style, 1 table, 3 figures

Published
2009
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28. First AGILE Catalog of High Confidence Gamma-Ray Sources

Author

Pittori, C., Verrecchia, F., Chen, A. W., 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, P. W., Cocco, V., Colafrancesco, S., Contessi, T., Costa, E., Cutini, S., D'Ammando, 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
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., Comment: 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
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29. MULTIWAVELENGTH OBSERVATIONS OF A TeV-FLARE FROM W COMAE

Author

Veritas, Collaboration, Acciari, V. A., Aliu, E., Aune, T., Beilicke, M., Benbow, W., Bottcher, M., Boltuch, D., Buckley, J. H., Bradbury, S. M., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Duke, C., Falcone, A., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Lebohec, S., Maier, G., Mcarthur, S., Mccann, A., Mccutcheon, M., Millis, J., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Sembroski, G. H., Smith, A. W., Steele, D., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Agile, The Team, Pian, E., Vercellone, S., Donnarumma, I., D Ammando, F., Bulgarelli, A., Chen, A. W., Giuliani, A., Longo, F., Pacciani, L., Pucella, G., Vittorini, V., Tavani, M., Argan, A., Barbiellini, G., Caraveo, P., Cattaneo, P. W., Cocco, V., Costa, E., Del Monte, E., Paris, G., Di Cocco, G., Evangelista, Y., Feroci, M., 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., Morselli, A., Pellizzoni, A., Perotti, F., Piano, G., Picozza, P., Pilia, M., Porrovecchio, G., Prest, M., Rapisarda, M., Rappoldi, A., Rubini, A., Soffitta, S. Sabatini P., Trifoglio, M., Trois, A., Vallazza, E., Zambra, A., Zanello, D., Pittori, C., Santolamazza, P., Verrecchia, F., Giommi, P., Colafrancesco, S., Salotti, L., Massimo Villata, Raiteri, C. M., Aller, H. D., Aller, M. F., Arkharov, A. A., Efimova, N. V., Larionov, V. M., Leto, P., Ligustri, R., Lindfors, E., Pasanen, M., Kurtanidze, O. M., Tetradze, S. D., Lahteenmaki, A., Kotiranta, M., Cucchiara, A., Romano, P., Nesci, R., Pursimo, T., Heidt, J., Benitez, E., Hiriart, D., Nilsson, K., Berdyugin, A., Mujica, R., Dultzin, D., Lopez, J. M., Mommert, M., Sorcia, M., La Calle Perez, I., V. A., Acciari, E., Aliu, T., Aune, M., Beilicke, W., Benbow, M., Bottcher, D., Boltuch, J. H., Buckley, S. M., Bradbury, V., Bugaev, K., Byrum, A., Cannon, A., Cesarini, L., Ciupik, P., Cogan, W., Cui, R., Dickherber, C., Duke, A., Falcone, J. P., Finley, P., Fortin, L., Fortson, A., Furni, N., Galante, D., Gall, K., Gibb, G. H., Gillander, J., Grube, R., Guenette, G., Gyuk, D., Hanna, J., Holder, C. M., Hui, T. B., Humensky, P., Kaaret, N., Karlsson, M., Kertzman, D., Kieda, A., Konopelko, H., Krawczynski, F., Krennrich, M. J., Lang, S., Lebohec, G., Maier, S., Mcarthur, A., Mccann, M., Mccutcheon, J., Milli, P., Moriarty, R. A., Ong, A. N., Otte, D., Pandel, J. S., Perkin, A., Pichel, M., Pohl, J., Quinn, K., Ragan, L. C., Reye, P. T., Reynold, E., Roache, H. J., Rose, G. H., Sembroski, A. W., Smith, D., Steele, M., Theiling, S., Thibadeau, A., Varlotta, V. V., Vassiliev, S., Vincent, S. P., Wakely, J. E., Ward, T. C., Weeke, A., Weinstein, T., Weisgarber, D. A., William, S., Wissel, M., Wood, E., Pian, S., Vercellone, I., Donnarumma, F., D'Ammando, A., Bulgarelli, A. W., Chen, A., Giuliani, Longo, Francesco, L., Pacciani, G., Pucella, V., Vittorini, M., Tavani, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, V., Cocco, E., Costa, E. D., Monte, G. D., Pari, G. D., Cocco, Y., Evangelista, M., Feroci, 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, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, G., Porrovecchio, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, A., Zambra, D., Zanello, C., Pittori, P., Santolamazza, F., Verrecchia, P., Giommi, S., Colafrancesco, L., Salotti, M., Villata, C. M., Raiteri, H. D., Aller, M. F., Aller, A. A., Arkharov, N. V., Efimova, V. M., Larionov, P., Leto, R., Ligustri, E., Lindfor, M., Pasanen, O. M., Kurtanidze, S. D., Tetradze, A., Lahteenmaki, M., Kotiranta, A., Cucchiara, P., Romano, R., Nesci, T., Pursimo, J., Heidt, E., Benitez, D., Hiriart, K., Nilsson, A., Berdyugin, R., Mujica, D., Dultzin, J. M., Lopez, M., Mommert, M., Sorcia, I. D., Perez, Acciari VA, Aliu E, Aune T, Beilicke M, Benbow W, Bottcher M, Boltuch D, Buckley JH, Bradbury SM, Bugaev V, Byrum K, Cannon A, Cesarini A, Ciupik L, Cogan P, Cui W, Dickherber R, Duke C, Falcone A, Finley JP, Fortin P, Fortson L, Furniss A, Galante N, Gall D, Gibbs K, Gillanders GH, Grube J, Guenette R, Gyuk G, Hanna D, Holder J, Hui CM, Humensky TB, Kaaret P, Karlsson N, Kertzman M, Kieda D, Konopelko A, Krawczynski H, Krennrich F, Lang MJ, LeBohec S, Maier G, McArthur S, McCann A, McCutcheon M, Millis J, Moriarty P, Ong RA, Otte AN, Pandel D, Perkins JS, Pichel A, Pohl M, Quinn J, Ragan K, Reyes LC, Reynolds PT, Roache E, Rose HJ, Sembroski GH, Smith AW, Steele D, Theiling M, Thibadeau S, Varlotta A, Vassiliev VV, Vincent S, Wakely SP, Ward JE, Weekes TC, Weinstein A, Weisgarber T, Williams DA, Wissel S, Wood M, Pian E, Vercellone S, Donnarumma I, DAmmando F, Bulgarelli A, Chen AW, Giuliani A, Longo F, Pacciani L, Pucella G, Vittorini V, Tavani M, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Cocco V, Costa E, Del Monte E, De Paris G, Di Cocco G, Evangelista Y, Feroci M, 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, Morselli A, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Porrovecchio G, Prest M, Rapisarda M, Rappoldi A, Rubini A, Sabatini S, Soffitta P, Trifoglio M, Trois A, Vallazza E, Zambra A, Zanello D, Pittori C, Santolamazza P, Verrecchia F, Giommi P, Colafrancesco S, Salotti L, Villata M, Raiteri CM, Aller HD, Aller MF, Arkharov AA, Efimova NV, Larionov VM, Leto P, Ligustri R, Lindfors E, Pasanen M, Kurtanidze OM, Tetradze SD, Lahteenmaki A, Kotiranta M, Cucchiara A, Romano P, Nesci R, Pursimo T, Heidt J, Benitez E, Hiriart D, Nilsson K, Berdyugin A, Mujica R, Dultzin D, Lopez JM, Mommert M, Sorcia M, and Perez ID

Subjects
Agile, High energy, agile space mission, Astrophysics::High Energy Astrophysical Phenomena, bl-lacertae objects, FOS: Physical sciences, Flux, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, telescope, 01 natural sciences, High Energy Gamma-ray Astronomy, blazar, law.invention, multiwavelength, BL Lacertae, law, 0103 physical sciences, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Very High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, Gamma ray, background-radiation, Astronomy and Astrophysics, gamma-ray emission, lac objects, spectral energy-distributions, veritas observations, Space and Planetary Science, source list, Spectral energy distribution, BL Lacertae objects: individual (W Com), Astrophysics - High Energy Astrophysical Phenomena, gamma rays: observations, Flare, BL Lac object
Abstract

We report results from an intensive multiwavelength campaign on the intermediate-frequency-peaked BL Lacertae object W Com (z=0.102) during a strong outburst of very high energy gamma-ray emission in June 2008. The very high energy gamma-ray signal was detected by VERITAS on 2008 June 7-8 with a flux F(>200 GeV) = (5.7+-0.6)x10^-11 cm-2s-1, about three times brighter than during the discovery of gamma-ray emission from W Com by VERITAS in 2008 March. The initial detection of this flare by VERITAS at energies above 200 GeV was followed by observations in high energy gamma-rays (AGILE, E>100 MeV), and X-rays (Swift and XMM-Newton), and at UV, and ground-based optical and radio monitoring through the GASP-WEBT consortium and other observatories. Here we describe the multiwavelength data and derive the spectral energy distribution (SED) of the source from contemporaneous data taken throughout the flare., 26 pages, 5 figures; Accepted for publication by The Astrophysical Journal

Published
2009

30. Galactic Sources Science With Agile: The Case Of The Carina Region

Author

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

Subjects
Nuclear and High Energy Physics, Astrophysics::High Energy Astrophysical Phenomena, colliding wind binary, FOS: Physical sciences, Carina, Astrophysics, galactic gamma ray sky, High Energy Gamma-ray Astronomy, AGILE, Astrophysics::Solar and Stellar Astrophysics, Gamma rays: observations, Individual stars (Eta Carinae), Stars: winds, Outflows, X-rays: bynaries, Surface brightness, Instrumentation, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Colliding-wind binary, Physics, Nebula, Star formation, Molecular cloud, Gamma ray, Astronomy, Galactic sources, Galactic plane, Star cluster, Galactic source, Astrophysics - High Energy Astrophysical Phenomena
Abstract

During its first 2 years of operation, the gamma-ray AGILE satellite accumulated an extensive dataset for the Galactic plane. The data have been monitored for transient sources and several gamma-ray sources were detected. Their variability and possible association were studied. In this talk we will focus on the results of extensive observations of the Carina Region during the time period 2007 July - 2009 January, for a total livetime of ~130 days. The region is extremely complex, hosting massive star formation, with the remarkable colliding wind binary Eta Carinae, massive star clusters and HII regions (e.g. NGC 3324, RCW49, Westerlund II) and a giant molecular cloud extending over 150 pc (between l=284.7 and l=289). The Carina Nebula itself is the largest and IR highest surface brightness nebula of the Southern emisphere. We monitored several gamma ray sources in the Carina Region. In particular we detect a gamma ray source (1AGL J1043-5931) consistent with the position of Eta Carinae and report a remarkable 2-days gamma-ray flaring episode from this source on 2008 Oct 11-13. If 1AGL J1043-5931 is associated with the Eta Car system, our data provides the long sought first detection above 100 MeV of a colliding wind binary., 5 pages, 5 figures, proceedings of RICAP 2009

Published
2012

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

Author

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

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

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

Published
2011

32. 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

33. The flaring blazars of the first 1.5 years of the AGILE mission

Author

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

Subjects
Nuclear and High Energy Physics, Active galactic nucleus, Galaxies: active, Galaxies: quasars: general, Galaxies: jets, Radiation mechanisms: non-thermal, Flux, FOS: Physical sciences, Astrophysics, blazar, law.invention, AGILE, Telescope, law, Egret, gamma-ray, Blazar, Instrumentation, Large fov, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), biology, Astronomy, Quasar, Active Galactic Nuclei, biology.organism_classification, multiwavelength campaign, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object
Abstract

We report the AGILE γ -ray observations and the results of the multiwavelength campaigns on seven flaring blazars detected by the mission: During two multiwavelength campaigns, we observed γ -ray activity from two Flat Spectrum Radio Quasars of the Virgo region, e.g. 3C 279 and 3C 273 (the latter being the first extragalactic source simultaneously observed with the γ -ray telescope and the hard X ray imager of the mission). Due to the large FOV of the AGILE/GRID instrument, we achieved an almost continuous coverage of the FSRQ 3C 454.3. The source showed flux above 10 −6 photons/cm 2 /s ( E > 100 MeV ) and showed day by day variability during all the AGILE observing periods. In the EGRET era, the source was found in high γ -ray activity only once. An other blazar, PKS 1510-089 was frequently found in high γ -ray activity. S5 0716+71, an intermediate BL Lac object, exhibited a very high γ -ray activity and fast γ -ray variability during a period of intense optical activity. We observed high γ -ray activity from W Comae, a BL Lac object, and Mrk 421, a high energy peaked BL Lac object. For this source, a multiwavelength campaign from optical to TeV has been performed.

Published
2011

34. 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

35. 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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36. 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

37. AGILE OBSERVATIONS OF THE 'SOFT' GAMMA-RAY PULSAR PSR B1509-58

Author

A. Argan, Andrea Bulgarelli, Enrico Costa, G. De Paris, F. Perotti, Patrick Weltevrede, Simon Johnston, A. Giuliani, A. Morselli, I. Donnarumma, A. Rappoldi, E. Vallazza, G. Pucella, V. Cocco, Claudio Labanti, A. W. Chen, C. Pittori, T. Froysland, E. Del Monte, A. Pellizzoni, Francesco Lazzarotto, Massimiliano Fiorini, N. D'Amico, S. Sabatini, Y. Evangelista, Francesco Longo, Andrea Possenti, G. Di Cocco, Paolo Lipari, F. Lucarelli, Giovanni F. Bignami, Marco Feroci, L. Salotti, F. Fuschino, Luigi Pacciani, D. Zanello, A. Zambra, S. Vercellone, M. Burgay, V. Vittorini, Filippo D'Ammando, Paolo Soffitta, M. Trifoglio, Massimo Rapisarda, Guido Barbiellini, P. Santolamazza, Maura Pilia, Alessio Trois, Paolo Giommi, I. Lapshov, Paolo Esposito, Fulvio Gianotti, M. Prest, A. De Luca, P. A. Caraveo, M. Galli, Piergiorgio Picozza, F. Verrecchia, G. Piano, Marco Tavani, Martino Marisaldi, Sandro Mereghetti, P. W. Cattaneo, Pilia M, Pellizzoni A, Trois A, Verrecchia F, Esposito P, Weltevrede P, Johnston S, Burgay M, Possenti A, Del Monte E, Fuschino F, Santolamazza P, Chen A, Giuliani A, Caraveo P, Mereghetti S, Tavani M, Argan A, Costa E, D'Amico N, De Luca A, Evangelista Y, Feroci M, Longo F, Marisaldi M, Barbiellini G, Bulgarelli A, Cattaneo PW, Cocco V, DAmmando F, De Paris G, Di Cocco G, Donnarumma I, Fiorini M, Froysland T, Galli M, Gianotti F, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Morselli A, Pacciani L, Perotti F, Piano G, Picozza P, Prest M, Pucella G, Rapisarda M, Rappoldi A, Sabatini S, Soffitta P, Trifoglio M, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Lucarelli F, Giommi P, Salotti L, Bignami GF, M., Pilia, A., Pellizzoni, A., Troi, F., Verrecchia, P., Esposito, P., Weltevrede, S., Johnston, M., Burgay, A., Possenti, E. D., Monte, F., Fuschino, P., Santolamazza, A., Chen, A., Giuliani, P., Caraveo, S., Mereghetti, M., Tavani, A., Argan, E., Costa, N., D'Amico, A. D., Luca, Y., Evangelista, M., Feroci, Longo, Francesco, M., Marisaldi, G., Barbiellini, A., Bulgarelli, P. W., Cattaneo, V., Cocco, F., D'Ammando, G. D., Pari, G. D., Cocco, I., Donnarumma, M., Fiorini, T., Froysland, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, A., Morselli, L., Pacciani, F., Perotti, G., Piano, P., Picozza, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, S., Sabatini, P., Soffitta, M., Trifoglio, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, F., Lucarelli, P., Giommi, L., Salotti, and G. F., Bignami

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Agile, pulsar, gamma ray, High Energy Gamma-ray Astronomy, AGILE satellite, Pulsar, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, gamma rays: stars – pulsars: general – pulsars: individual (PSR J1513–5908 (B1509–58)) – stars: neutron, Astronomy and Astrophysics, Astrophysics, Light curve, Electromagnetic radiation, Spectral line, Neutron star, Pair production, Space and Planetary Science, Spectral energy distribution, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the results of new Agile observations of PSR B1509-58 performed over a period of 2.5 years following the detection obtained with a subset of the present data. The modulation significance of the lightcurve above 30 MeV is at a 5$\sigma$ confidence level and the lightcurve is similar to those found earlier by Comptel up to 30 MeV: a broad asymmetric first peak reaching its maximum 0.39 +/- 0.02 cycles after the radio peak plus a second peak at 0.94 +/- 0.03. The gamma-ray spectral energy distribution of the pulsed flux detected by Comptel and Agile is well described by a power-law (photon index alpha=1.87+/-0.09) with a remarkable cutoff at E_c=81 +/- 20 MeV, representing the softest spectrum observed among gamma-ray pulsars so far. The pulsar luminosity at E > 1 MeV is $L_{\gamma}=4.2^{+0.5}_{-0.2} \times10^{35}$ erg/s, assuming a distance of 5.2 kpc, which implies a spin-down conversion efficiency to gamma-rays of $\sim 0.03$. The unusual soft break in the spectrum of PSR B1509-58 has been interpreted in the framework of polar cap models as a signature of the exotic photon splitting process in the strong magnetic field of this pulsar. In this interpretation our spectrum constrains the magnetic altitude of the emission point(s) at 3 km above the neutron star surface, implying that the attenuation may not be as strong as formerly suggested because pair production can substitute photon splitting in regions of the magnetosphere where the magnetic field becomes too low to sustain photon splitting. In the case of an outer-gap scenario, or the two pole caustic model, better constraints on the geometry of the emission would be needed from the radio band in order to establish whether the conditions required by the models to reproduce Agile lightcurves and spectra match the polarization measurements., Comment: 17 pages, 2 figures, accepted for publication in ApJ

Published
2010

38. 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

39. 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

40. AGILE detection of a rapid gamma-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

Author

Dario Gasparrini, A. W. Chen, Alan P. Marscher, P. Giommi, C. Pittori, Filippo D'Ammando, T. Froysland, A. Argan, Andrea Bulgarelli, Enrico Costa, M. Sorcia, Carla Buemi, F. Fuschino, Svetlana G. Jorstad, Massimo Rapisarda, Marco Feroci, Arnaud Ferrari, Luigi Pacciani, Uwe Bach, Corrado Trigilio, F. Boffelli, G. De Paris, Jochen Heidt, L. A. Antonelli, Deborah Dultzin, F. Perotti, Raúl Mújica, C. M. Raiteri, Lars Fuhrmann, G. Umana, D. Zanello, A. Zambra, A. Morselli, Mark Gurwell, Paolo Soffitta, Margo F. Aller, Kari Nilsson, Marco Tavani, E. Vallazza, Wen Ping Chen, Tatiana S. Konstantinova, S. Sabatini, I. M. McHardy, Ekaterina Koptelova, A. Rappoldi, M. Fiorini, Ivan Agudo, Martino Marisaldi, José L. Gómez, V. Cocco, J. M. Lopez, Valeri M. Larionov, S. Vercellone, Elina Lindfors, A. Pellizzoni, E. Del Monte, H. Y. Hsiao, G. Pucella, F. Longo, I. Lapshov, L. Salotti, Ivan S. Troitsky, A. Giuliani, Sandro Mereghetti, Paolo Lipari, L. O. Takalo, Mar Roca-Sogorb, P. W. Cattaneo, Omar M. Kurtanidze, Brian W. Taylor, G. Di Rico, M. Trifoglio, David Hiriart, S. Colafrancesco, P. Picozza, G. Barbiellini, G. Piano, Hugh D. Aller, Fulvio Gianotti, Maura Pilia, Alessio Trois, A. A. Arkharov, B. Preger, G. Di Cocco, Givi N. Kimeridze, S. Cutini, Claudio Labanti, Erika Benítez, P. Santolamazza, I. Donnarumma, Y. Evangelista, A. Di Paola, M. Galli, E. N. Kopatskaya, P. A. Caraveo, Paolo Leto, F. Verrecchia, Michael Mommert, Francesco Lazzarotto, Andrei Berdyugin, M. Pasanen, D. A. Melnichuk, M. Prest, M. Villata, D. Blinov, V. Vittorini, DAmmando F, Pucella G, Raiteri CM, Villata M, Vittorini V, Vercellone S, Donnarumma I, Longo F, Tavani M, Argan A, Barbiellini G, Boffelli F, Bulgarelli A, Caraveo P, Cattaneo PW, Chen AW, Cocco V, Costa E, Del Monte E, De Paris G, Di Cocco G, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Froysland T, Fuschino F, Galli M, Gianotti F, Giuliani A, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Marisaldi M, Mereghetti S, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Prest M, Rapisarda M, Rappoldi A, Sabatini S, Soffitta P, Trifoglio M, Trois A, Vallazza E, Zambra A, Zanello D, Agudo I, Aller MF, Aller HD, Arkharov AA, Bach U, Benitez E, Berdyugin A, Blinov DA, Buemi CS, Chen WP, Di Paola A, Di Rico G, Dultzin D, Fuhrmann L, Gomez JL, Gurwell MA, Jorstad SG, Heidt J, Hiriart D, Hsiao HY, Kimeridze G, Konstantinova TS, Kopatskaya EN, Koptelova E, Kurtanidze O, Larionov VM, Leto P, Lindfors E, Lopez JM, Marscher AP, McHardy IM, Melnichuk DA, Mommert M, Mujica R, Nilsson K, Pasanen M, Roca-Sogorb M, Sorcia M, Takalo LO, Taylor B, Trigilio C, Troitsky IS, Umana G, Antonelli LA, Colafrancesco S, Cutini S, Gasparrini D, Pittori C, Preger B, Santolamazza P, Verrecchia F, Giommi P, Salotti L, F., D'Ammando, G., Pucella, C. M., Raiteri, M., Villata, V., Vittorini, S., Vercellone, I., Donnarumma, Longo, Francesco, M., Tavani, A., Argan, G., Barbiellini, F., Boffelli, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, A. W., Chen, V., Cocco, E., Costa, E. D., Monte, G. D., Pari, G. D., Cocco, Y., Evangelista, M., Feroci, A., Ferrari, M., Fiorini, T., Froysland, F., Fuschino, M., Galli, F., Gianotti, A., Giuliani, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, M., Marisaldi, S., Mereghetti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, S., Sabatini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, A., Zambra, D., Zanello, I., Agudo, M. F., Aller, H. D., Aller, A. A., Arkharov, U., Bach, E., Benitez, A., Berdyugin, D. A., Blinov, C. S., Buemi, W. P., Chen, A. D., Paola, G. D., Rico, D., Dultzin, L., Fuhrmann, J. L., Gomez, M. A., Gurwell, S. G., Jorstad, J., Heidt, D., Hiriart, H. Y., Hsiao, G., Kimeridze, T. S., Konstantinova, E. N., Kopatskaya, E., Koptelova, O., Kurtanidze, V. M., Larionov, P., Leto, E., Lindfor, J. M., Lopez, A. P., Marscher, I. M., Mchardy, D. A., Melnichuk, M., Mommert, R., Mujica, K., Nilsson, M., Pasanen, M., Roca Sogorb, M., Sorcia, L. O., Takalo, B., Taylor, C., Trigilio, I. S., Troitsky, G., Umana, L. A., Antonelli, S., Colafrancesco, S., Cutini, D., Gasparrini, C., Pittori, B., Preger, P., Santolamazza, F., Verrecchia, P., Giommi, and L., Salotti

Subjects
Agile, Active galactic nucleus, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Radio spectrum, gamma-ray flare, High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, law.invention, law, quasar, Blazar, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Gamma ray, Compton scattering, Astronomy and Astrophysics, Quasar, Space and Planetary Science, gamma-rays: observations – mechanism: non-thermal – quasars: individual (PKS 1510-089), Spectral energy distribution, Astrophysics - High Energy Astrophysical Phenomena, Flare, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report the detection by the AGILE satellite of a rapid gamma-ray flare from the powerful gamma-ray quasar PKS 1510-089, during a pointing centered on the Galactic Center region from 1 March to 30 March 2008. This source has been continuosly monitored in the radio-to-optical bands by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT). Moreover, the gamma-ray flaring episode triggered three ToO observations by the Swift satellite in three consecutive days, starting from 20 March 2008. In the period 1-16 March 2008, AGILE detected gamma-ray emission from PKS 1510-089 at a significance level of 6.2-sigma with an average flux over the entire period of (84 +/- 17) x 10^{-8} photons cm^{-2} s^{-1} for photon energies above 100 MeV. After a predefined satellite re-pointing, between 17 and 21 March 2008, AGILE detected the source at a significance level of 7.3-sigma, with an average flux (E > 100 MeV) of (134 +/- 29) x 10^{-8} photons cm^{-2} s^{-1} and a peak level of (281 +/- 68) x 10^{-8} photons cm^{-2} s^{-1} with daily integration. During the observing period January-April 2008, the source also showed an intense and variable optical activity, with several flaring episodes and a significant increase of the flux was observed at millimetric frequencies. Moreover, in the X-ray band the Swift/XRT observations seem to show an harder-when-brighter behaviour of the source spectrum. The spectral energy distribution of mid-March 2008 is modelled with a homogeneous one-zone synchrotron self Compton emission plus contributions from inverse Compton scattering of external photons from both the accretion disc and the broad line region. Indeed, some features in the optical-UV spectrum seem to indicate the presence of Seyfert-like components, such as the little blue bump and the big blue bump., 10 pages, 4 figures and 2 tables, accepted for publication in A&A

Published
2009

41. Detection of Gamma-Ray Emission from the Eta-Carinae Region

Author

Massimo Rapisarda, C. Pittori, D. Zanello, Roberto Viotti, L. Salotti, Filippo D'Ammando, T. Froysland, Michael F. Corcoran, Claudio Labanti, Maura Pilia, Elena Pian, Paolo Soffitta, A. Zambra, F. Boffelli, Francesco Lazzarotto, Alessio Trois, Geiland Porrovecchio, A. Pellizzoni, F. Fuschino, A. Giuliani, Francesco Longo, Marco Feroci, Luigi Pacciani, L. A. Antonelli, Fulvio Gianotti, G. Piano, Y. Evangelista, G. Di Cocco, M. Prest, E. Del Monte, Marcello Mastropietro, I. Donnarumma, S. Vercellone, Paolo Lipari, I. Lapshov, E. Moretti, V. Vittorini, G. Pucella, G. De Paris, M. Trifoglio, P. A. Caraveo, V. Cocco, Marco Tavani, S. Sabatini, Sergio Colafrancesco, Ennio Morelli, M. Galli, Sandro Mereghetti, P. W. Cattaneo, Piergiorgio Picozza, Massimiliano Fiorini, F. Verrecchia, Martino Marisaldi, A. W. Chen, F. Perotti, A. Morselli, A. Argan, P. Santolamazza, Andrea Bulgarelli, Enrico Costa, Alda Rubini, Paolo Giommi, A. Rappoldi, E. Vallazza, Attilio Ferrari, Guido Barbiellini, Tavani M, Sabatini S, Pian E, Bulgarelli A, Caraveo P, Viotti R F, Corcoran M F, Giuliani A, Pittori C, Verrecchia F, Vercellone S, Mereghetti S, Argan A, Barbiellini G, Boffelli F, Cattaneo P W, Chen A W, Cocco V, DAmmando F, Costa E, DeParis G, Del Monte E, Di Cocco G, Donnarumma I, Evangelista Y, Ferrari A, Feroci M, Fiorini M, Froysland T, Fuschino F, Galli M, Gianotti F, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mastropietro M, Morelli E, Moretti E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Porrovecchio G, Pucella G, Prest M, Rapisarda M, Rappoldi A, Rubini A, Soffitta P, Trifoglio M, Trois A, Vallazza E, Vittorini V, Zambra A, Zanello D, Santolamazza P, Giommi P, Colafrancesco S, Antonelli L A, Salotti L, M., Tavani, S., Sabatini, E., Pian, A., Bulgarelli, P., Caraveo, R. F., Viotti, M. F., Corcoran, A., Giuliani, C., Pittori, F., Verrecchia, S., Vercellone, S., Mereghetti, A., Argan, G., Barbiellini, F., Boffelli, P. W., Cattaneo, A. W., Chen, V., Cocco, F., D'Ammando, E., Costa, G. D., Pari, E. D., Monte, G. D., Cocco, I., Donnarumma, Y., Evangelista, A., Ferrari, M., Feroci, M., Fiorini, T., Froysland, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, M., Mastropietro, E., Morelli, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, G., Porrovecchio, G., Pucella, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, V., Vittorini, A., Zambra, D., Zanello, P., Santolamazza, P., Giommi, S., Colafrancesco, L. A., Antonelli, and L., Salotti

Subjects
Agile, Astrophysics::High Energy Astrophysical Phenomena, Carina Nebula, Flux, FOS: Physical sciences, Astrophysics, Radiation, High Energy Gamma-ray Astronomy, Luminosity, gamma rays: observations, stars: individual: Eta Carinae, stars: winds, outflows, X-rays: binaries, Astrophysics::Solar and Stellar Astrophysics, wind binary Eta Carinae, Astrophysics::Galaxy Astrophysics, Colliding-wind binary, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Nebula, Gamma ray, Galactic region, Astronomy and Astrophysics, AGILE satellite, Unidentified Gamma-ray Sources, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the results of extensive observations by the gamma-ray AGILE satellite of the Galactic region hosting the Carina nebula and the remarkable colliding wind binary Eta Carinae (Eta Car) during the period 2007 July to 2009 January. We detect a gamma-ray source (1AGL J1043-5931) consistent with the position of Eta Car. If 1AGL J1043-5931 is associated with the Eta Car system our data provide the long sought first detection above 100 MeV of a colliding wind binary. The average gamma-ray flux above 100 MeV and integrated over the pre-periastron period 2007 July to 2008 October is F = (37 +/- 5) x 10-8 ph cm-2 s-1 corresponding to an average gamma-ray luminosity of L = 3.4 x 10^34 erg s-1 for a distance of 2.3 kpc. We also report a 2-day gamma-ray flaring episode of 1AGL J1043-5931 on 2008 Oct. 11-13 possibly related to a transient acceleration and radiation episode of the strongly variable shock in the system., Comment: 5 pages, 4 figure, accepted for publication in ApJ Letters

Published
2009

42. 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

43. 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

44. Monitoring the hard X-ray sky with SuperAGILE

Author

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

Subjects
Agile, Photon, High Energy Gamma-ray Astronomy, AGILE satellite, X-ray sources, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Field of view, SuperAgile, x-ray detector, extragalactic and galactic sources, Optics, Angular resolution, Instrumentation and Methods for Astrophysics (astro-ph.IM), media_common, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), COSMIC cancer database, business.industry, Detector, Gamma ray, Astronomy and Astrophysics, instrumentation: detectors – X-rays: binaries – X-rays: general, Space and Planetary Science, Sky, Celestial coordinate system, business, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

SuperAGILE is the hard X-ray monitor of the AGILE gamma ray mission, in orbit since 23$^{rd}$ April 2007. It is an imaging experiment based on a set of four independent silicon strip detectors, equipped with one-dimensional coded masks, operating in the nominal energy range 18-60 keV. The main goal of SuperAGILE is the observation of cosmic sources simultaneously with the main gamma-ray AGILE experiment, the Gamma Ray Imaging Detector (GRID). Given its $\sim$steradian-wide field of view and its $\sim$15 mCrab day-sensitivity, SuperAGILE is also well suited for the long-term monitoring of Galactic compact objects and the detection of bright transients. The SuperAGILE detector properties and design allow for a 6 arcmin angular resolution in each of the two independent orthogonal projections of the celestial coordinates. Photon by photon data are continuously available by the experiment telemetry, and are used to derive images and fluxes of individual sources, with integration times depending on the source intensity and position in the field of view. In this paper we report on the main scientific results achieved by SuperAGILE over its first two years in orbit, until April 2009., Comment: Accepted for publication on Astronomy & Astrophysics

Published
2009
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45. 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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46. DISCOVERY OF NEW GAMMA-RAY PULSARS WITH AGILE

Author

Francesco Longo, S. Sabatini, Maura Pilia, Y. Evangelista, Alessio Trois, A. De Luca, Teresa Mineo, G. De Paris, P. A. Caraveo, D. Zanello, Marco Tavani, Fulvio Gianotti, V. Vittorini, Martino Marisaldi, G. Di Cocco, M. Trifoglio, A. W. Chen, Massimiliano Fiorini, B. Preger, A. Rappoldi, E. Vallazza, Ismaël Cognard, Patrick Weltevrede, F. Fornari, Paolo Esposito, M. Prest, Claudio Labanti, A. Giuliani, V. Cocco, N. D'Amico, Massimo Rapisarda, Sandro Mereghetti, P. W. Cattaneo, A. Argan, Andrea Bulgarelli, F. Perotti, Enrico Costa, I. Lapshov, Simon Johnston, I. Donnarumma, L. Salotti, A. Zambra, Francesco Lazzarotto, E. Del Monte, F. Boffelli, M. Galli, Piergiorgio Picozza, F. Verrecchia, Alessandro Corongiu, C. Pittori, T. Froysland, A. Pellizzoni, Paolo Lipari, Giovanni F. Bignami, Gilles Theureau, F. Fuschino, M. Burgay, A. Morselli, G. Pucella, Michael Kramer, Marco Feroci, Luigi Pacciani, S. Vercellone, G. Piano, Guido Barbiellini, P. Santolamazza, Paolo Giommi, Filippo D'Ammando, Paolo Soffitta, Andrea Possenti, INAF - Osservatorio Astronomico di Cagliari (OAC), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Milano (OAM), INAF - Osservatorio Astronomico di Roma (OAR), INAF - Osservatorio Astronomico di Bologna (OABO), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Australia Telescope National Facility (ATNF), Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester [Manchester], Università degli studi di Trieste, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Pavia (INFN), Istituto Nazionale di Fisica Nucleare (INFN), Istituto Nazionale di Fisica Nucleare [Sezione di Roma 1] (INFN), Istituto Nazionale di Fisica Nucleare, Agenzia Spaziale Italiana (ASI), Istituto Universitario di Studi Superiori (IUSS), Pellizzoni A, Pilia M, Possenti A, Chen A, Giuliani A, Trois A, Caraveo P, Del Monte E, Fornari F, Fuschino F, Mereghetti S, Tavani M, Argan A, Burgay M, Cognard I, Corongiu A, Costa E, D'Amico N, De Luca A, Esposito P, Evangelista Y, Feroci M, Johnston S, Kramer M, Longo F, Marisaldi M, Theureau G, Weltevrede P, Barbiellini G, Boffelli F, Bulgarelli A, Cattaneo P W, Cocco V, DAmmando F, DeParis G, Di Cocco G, Donnarumma I, Fiorini M, Froysland T, Galli M, Gianotti F, Labanti C, Lapshov, I., Lazzarotto, F., Lipari P, Mineo T, Morselli A, Pacciani L, Perotti F, Piano G, Picozza P, Prest M, Pucella G, Rapisarda M, Rappoldi A, Sabatini S, Soffitta P, Trifoglio M, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Verrecchia F, Preger B, Santolamazza P, Giommi P, Salotti L, Bignami G F, A., Pellizzoni, M., Pilia, A., Possenti, A., Chen, A., Giuliani, A., Troi, P., Caraveo, E. D., Monte, F., Fornari, F., Fuschino, S., Mereghetti, M., Tavani, A., Argan, M., Burgay, I., Cognard, A., Corongiu, E., Costa, N., D'Amico, A. D., Luca, P., Esposito, Y., Evangelista, M., Feroci, S., Johnston, M., Kramer, Longo, Francesco, M., Marisaldi, G., Theureau, P., Weltevrede, G., Barbiellini, F., Boffelli, A., Bulgarelli, P. W., Cattaneo, V., Cocco, F., D'Ammando, G. D., Pari, G. D., Cocco, I., Donnarumma, M., Fiorini, T., Froysland, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, T., Mineo, A., Morselli, L., Pacciani, F., Perotti, G., Piano, P., Picozza, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, S., Sabatini, P., Soffitta, M., Trifoglio, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, B., Preger, P., Santolamazza, P., Giommi, L., Salotti, and G. F., Bignami

Subjects
Agile, High Energy Gamma-ray Astronomy, AGILE satellite, Pulsars, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, radio pulsar, Astrophysics, 01 natural sciences, stars: neutron, Pulsar, Millisecond pulsar, pulsars: general, 0103 physical sciences, Egret, pulsars: individual (PSR J2229+6114 PSR B1509–58 PSR B1821–24), 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), biology, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Gamma ray, Static timing analysis, Astronomy and Astrophysics, biology.organism_classification, gamma rays: observations, pulsars: general, pulsars: individual: PSR J2229 + 6114 PSR B1509 – 58 PSR B1821 – 24, stars: neutron, Space and Planetary Science, Globular cluster, Astrophysics - High Energy Astrophysical Phenomena, gamma rays: observations
Abstract

Using gamma-ray data collected by the Astrorivelatore Gamma ad Immagini LEggero (AGILE) satellite over a period of almost one year (from 2007 July to 2008 June), we searched for pulsed signals from 35 potentially interesting radio pulsars, ordered according to $F_{\gamma}\propto \sqrt{\dot{E}} d^{-2}$ and for which contemporary or recent radio data were available. AGILE detected three new top-ranking nearby and Vela-like pulsars with good confidence both through timing and spatial analysis. Among the newcomers we find pulsars with very high rotational energy losses, such as the remarkable PSR B1509-58 with a magnetic field in excess of 10^13 Gauss, and PSR J2229+6114 providing a reliable identification for the previously unidentified EGRET source 3EG 2227+6122. Moreover, the powerful millisecond pulsar B1821-24, in the globular cluster M28, is detected during a fraction of the observations. Four other promising gamma-ray pulsar candidates, among which is the notable J2043+2740 with an age in excess of 1 million years, show a possible detection in the timing analysis only and deserve confirmation., Comment: Minor changes to match the final ApJ version. 5 pages in emulate-apj style, 1 table, 3 figures

Published
2009
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