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85 results on '"AGILE satellite"'

1. Agile earth observation satellite constellations scheduling for large area target imaging using heuristic search

Author: Kandepi, Radhika, Saini, Himani, George, Raju K., Konduri, Subbarao, and Karidhal, Ritu
Published: 2024
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2. A Multiple Agile Satellite Staring Observation Mission Planning Method for Dense Regions.

Author: Huang, Weiquan, Wang, He, Yi, Dongbo, Wang, Song, Zhang, Binchi, and Cui, Jingwen
Subjects: *ANT algorithms, *LEVY processes, *ARTIFICIAL satellites
Abstract: To fully harness the burgeoning array of in-orbit satellite resources and augment the efficacy of dynamic surveillance of densely clustered terrestrial targets, this paper delineates the following methodologies. Initially, we leverage the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) clustering algorithm to aggregate the concentrated terrestrial targets, taking into account the field-of-view peculiarities of agile staring satellites. Subsequently, we architect a model for a synergistic multiple angle earth observation satellites (AEOSs) mission planning with the optimization objectives of observational revenue, minimal energy expenditure, and load balancing, factoring in constraints such as target visibility time window, AEOSs maneuverability, and satellite storage. To tackle this predicament, we propose an improved heuristic ant colony optimization (ACO) algorithm, utilizing the task interval, task priority, and the length of time a task can start observation as heuristic information. Furthermore, we incorporate the notion of the max–min ant system to regulate the magnitude of pheromone concentration, and we amalgamate global and local pheromone update strategies to expedite the convergence rate of the algorithm. We also introduce the Lévy flight improved pheromone evaporation coefficient to bolster the algorithm's capacity to evade local optima. Ultimately, through a series of simulation experiments, we substantiate the significant performance improvements achieved by the improved heuristic ant colony algorithm compared to the standard ant colony algorithm. We furnish proof of its efficacy in resolving the planning of multiple AEOS staring observation missions. [ABSTRACT FROM AUTHOR]
Published: 2023
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3. Reasoning-Based Scheduling Method for Agile Earth Observation Satellite with Multi-Subsystem Coupling.

Author: He, Changyuan, Dong, Yunfeng, Li, Hongjue, and Liew, Yingjia
Subjects: *ARTIFICIAL satellites, *SCHEDULING, *POWER resources, *ELECTRICAL energy, *DATA transmission systems
Abstract: With the rapid development of agile Earth observation satellites (AEOSs), these satellites are able to conduct more high-quality observation missions. Nevertheless, while completing these missions takes up more data transmission and electrical energy resources, it also increases the coupling within each satellite subsystem. To address this problem, we propose a reasoning-based scheduling method for an AEOS under multiple subsystem constraints. First, we defined the AEOS mission scheduling model with multi-subsystem constraints. Second, we put forward a state variable prediction method that reflects the different coupling states of a satellite after analyzing the coupling relationships between various subsystems and identifying the primary limiting coupling states for each subsystem. Third, we established the reasoning rules corresponding to the planning strategies of different coupling states of the satellite by adding two planning strategies based on the planning strategies of existing planning methods. By comparing the proposed method to three heuristic scheduling methods and a meta-heuristic scheduling method, the results show that our method has better performance in terms of scheduling results and efficiency. [ABSTRACT FROM AUTHOR]
Published: 2023
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4. Rapid Performance Sizing of Reaction Wheels in a Very High Resolution Remote Sensing Satellite Using Matching Diagram Technique

Author: Amir Reza Kosari, Alireza Ahmadi, Alireza Sharifi, and Masoud Khoshsima
Subjects: agile satellite, remote sensing, earth observation, passive scan, imaging payload, attitude determination and control subsystem, performance sizing, matching diagram, Technology, Astronomy, QB1-991
Abstract: Very High Resolution Passive Scan Agile Earth Observation Satellites are able to maneuver around all their three body axes and scan the target area in different directions, simultaneously. The most stringent mid-level requirements which dominate their attitude determination and control subsystem performance are applied in detumbling and fine pointing modes. These performance requirements are maneuverability, agility, accuracy and stability. In this research, first, we derive the analytical and statistical relationships between quantitative criteria of mid-level requirements and spatial resolution as a high-level mission requirement, next the design drivers of reaction wheels are extracted consequently. Then the size, mass and consuming power of an operational satellite and the reaction wheels torque authority and momentum capacity is guesstimated based on its imaging payload size and specifications.
Published: 2022
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5. Closed-form solution of attitude command generation for spin-to-spin maneuver.

Author: Mok, Sung-Hoon, Bang, Hyochoong, and Lee, Donghun
Subjects: *ANGULAR velocity
Abstract: In recent earth observing missions, agile satellites enable various imaging modes beyond the traditional along-track strip imaging. However, it requires maneuvering with boundary conditions of considerable angular velocity, i.e., spin-to-spin maneuvering. This paper proposes an attitude command generation method for spin-to-spin maneuvering that can provide feedforward commands for the attitude control loop. A general solution for arbitrary flight time is provided which steers a satellite to the given final attitude and angular velocity at the prescribed time. In addition, an alternative method is proposed that further improves the maneuvering speed, which is applicable to small-angle maneuvering cases. The proposed solutions are both closed-form which are more intuitive and easier to comprehend than numerical solutions. It also has a great advantage in computational efficiency, which could enable its use on-board in real time. Numerical examples demonstrate the performance of the proposed methods in a single maneuvering case as well as in a consecutive maneuvering case integrated with a realistic earth observing scenario. [ABSTRACT FROM AUTHOR]
Published: 2023
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6. Modeling and Solving for Multi-Satellite Cooperative Task Allocation Problem Based on Genetic Programming Method.

Author: Qi, Weihua, Yang, Wenyuan, Xing, Lining, and Yao, Feng
Subjects: *FEATURE extraction, *FLOOR plans, *EARTH stations, *GENETIC programming, *GENE expression, *INTEGER programming, *HEURISTIC
Abstract: The past decade has seen an increase in the number of satellites in orbit and in highly dynamic satellite requests, making the control by ground stations inefficient. The traditional management composed of ground planning with separate onboard execution is seriously lagging in response to dynamically incoming tasks. To meet the demand for the real-time response to emergent events, a multi-autonomous-satellite system with a central-distributed collaborative architecture was formulated by an integer programming model. Based on the structure, evolutionary rules were proposed to solve this problem by the use of sequence solution construction and a constructed heuristic method based on gene expression programming evolution. First, the features of the problem are extracted based on domain knowledge, then, the problem-solving rules are evolved by gene expression programming. The simulation results reflect that the evolutionary rule completely surpasses the three types of heuristic rules with adaptive mechanisms and achieves a solution effect close to meta-heuristic algorithms with a reasonably fast solving speed. [ABSTRACT FROM AUTHOR]
Published: 2022
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7. A versatile method for target area coverage analysis with arbitrary satellite attitude maneuver paths.

Author: Wang, Huijiang and Bai, Shengzhou
Subjects: *REMOTE sensing, *ARTIFICIAL satellites, *ATTITUDE (Psychology), *POLYGONS, *PROBLEM solving
Abstract: The agile Earth observation satellite (AEOS) is rapidly becoming the leading platform in Earth observation missions, as it implements attitude maneuvers and remote sensing simultaneously. However, present methods limit not only its remote sensing coverage to a small area during attitude maneuvering but also its operation to only certain orbit shapes. This paper proposes a new method, namely envelope curves hierarchical overlapping (ECHO), for the target area coverage analysis of an AEOS that implements attitude maneuvers during its mission. This method involves two stages. In the preparation stage, the satellite's instantaneous access area (IAA) is defined and analytically determined by solving the spatial equations of an oblate Earth and the sensor's view field. Then, the coverage belt of an AEOS is delineated by the envelope curves of a set of IAAs. In the manipulation stage, the coverage problem of a target area is solved by iteratively using the polygon clipping technique and hierarchically taking the intersection parts between the coverage belt and the target area. Numerical simulations demonstrate the practicability and high accuracy of the proposed method. • The coverage belt method is proposed to avoid traditional grid-point technique for area coverage. • Suitable for arbitrarily shaped target areas, all orbital types, multiple types of fields of view (FOV). • Attitude maneuver paths and WGS84 oblate Earth model are considered. • The multiple-time coverage problem is investigated and the polygon clipping technique is introduced to solve the problem. [ABSTRACT FROM AUTHOR]
Published: 2022
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8. Scheduling and Planning Framework for Time Delay Integration Imaging by Agile Satellite.

Author: Qiu, Wei, Xu, Chao, Ren, Zhigang, and Teo, Kok Lay
Subjects: *SCHEDULING, *REMOTE-sensing images, *NONLINEAR programming, *ENERGY consumption, *HEURISTIC algorithms
Abstract: The overall problem of scheduling and planning in space-borne observations has always been a focused research to enhance the efficiency of agile optical satellites. However, few studies have been conducted on specific problems about time delay integration (TDI) imaging missions. In this article, a novel framework is proposed to solve the coupling scheduling and planning problems of a TDI imaging mission with multiple target strips, in which the primary objective is the average imaging resolution, and the secondary objective is the energy consumption evaluated by torque integrals. The directional reversals in push-scan imaging and TDI accumulating are considered for the first time. With the combined efforts of geometric approximations, dynamic estimations, and neural network fitting, the original problem, which is a mixed-integer nonlinear programming, is split into a series of parameter optimization problems and solved by conventional methods. Thus, details of both the scheduling and planning are studied independently without the loss of the information provided by each other. Extensive numerical simulations, including extreme scenarios with high density and large-scale clusters, indicate that the decoupled framework is reliable in generating optimized profiles for arbitrary TDI imaging missions. [ABSTRACT FROM AUTHOR]
Published: 2022
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9. Agile Earth Observation Satellite Scheduling With a Quantum Annealer.

Author: Stollenwerk, Tobias, Michaud, Vincent, Lobe, Elisabeth, Picard, Mathieu, Basermann, Achim, and Botter, Thierry
Subjects: *ARTIFICIAL satellites, *QUANTUM annealing, *PRODUCTION scheduling, *NATURAL satellites, *BENCHMARK problems (Computer science), *SCHEDULING
Abstract: We present a comparison study of state-of-the-art classical optimization methods to a D-Wave 2000Q quantum annealer for the scheduling of agile Earth observation satellites. The problem is to acquire high-value images while obeying the attitude maneuvering constraint of the satellite. In order to investigate close to real-world problems, we created benchmark problems by simulating realistic scenarios. Our results show that a tuned quantum annealing approach can run faster when used to find the optimal solution than a classical exact solver for some of the problem instances. Moreover, we find that the solution quality of the quantum annealer is comparable to the heuristic method used operationally for small problem instances, but degrades rapidly due to the limited precision of the quantum annealer. [ABSTRACT FROM AUTHOR]
Published: 2021
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10. Design of agile satellite constellation based on hybrid-resampling particle swarm optimization method.

Author: Wang, Xiaohui, Zhang, Hao, Bai, Shengzhou, and Yue, Yuxian
Subjects: *PARTICLE swarm optimization, *ARTIFICIAL satellites, *ALGORITHMS, *INTERNATIONAL communication, *ATTITUDE (Psychology)
Abstract: In recent years, on-orbit constellations providing global communication and observation services have attracted widespread attention for economic and military interests. Thus, the design of satellite constellations has become a popular topic, which is mainly approached using different optimization methods. However, there are still some drawbacks to traditional methods, such as poor convergence and long computation time, which usually limit engineering applications. In this paper, a novel optimization method, the hybrid-resampling particle swarm optimization (HRPSO) algorithm, is proposed that provide higher efficiency for constellation design. The simulation results showed that the HRPSO algorithm is more efficient than the standard particle swarm optimization (PSO) algorithm and other improved resampling particle swarm optimization (RPSO) algorithms. Therefore, the HRPSO algorithm is expected to be a practical choice for constellation design. • Different types of sensors are considered, including complex cone and rectangular fields. • The attitude maneuver of the sensor is considered. • Different coverage performance indices are considered, including single- or double-fold coverage. • A novel and efficient HRPSO algorithm is proposed. [ABSTRACT FROM AUTHOR]
Published: 2021
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11. Algorithm with Patterned Singular Value Approach for Highly Reliable Autonomous Star Identification.

Author: Kiduck Kim and Hyochoong Bang
Subjects: *ARTIFICIAL satellite tracking, *AGILE software development, *IDENTIFICATION, *ALGORITHMS, *PATTERN matching, *PAPER arts
Abstract: In the work reported in this paper, a lost-in-space star pattern identification algorithm for agile spacecraft was studied. Generally, the operation of a star tracker is known to exhibit serious degradation or even failure during fast attitude maneuvers. While tracking methods are widely used solutions to handle the dynamic conditions, they require prior information about the initial orientation. Therefore, the tracking methods may not be adequate for autonomy of attitude and control systems. In this paper a novel autonomous identification method for dynamic conditions is proposed. Additional constraints are taken into account that can significantly decrease the number of stars imaged and the centroid accuracy. A strategy combining two existing classes for star pattern identification is proposed. The new approach is intended to provide a unique way to determine the identity of stars that promises robustness against noise and rapid identification. Moreover, representative algorithms implemented in actual space applications were utilized as counterparts to analyze the performance of the proposed method in various scenarios. Numerical simulations show that the proposed method is not only highly robust against positional noise and false stars, but also guarantees fast run-time, which is appropriate for high-speed applications. [ABSTRACT FROM AUTHOR]
Published: 2020
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12. Slew path planning of agile-satellite antenna pointing mechanism with optimal real-time data transmission performance.

Author: She, Yuchen, Li, Shuang, Li, Yinkang, Zhang, Liu, and Wang, Shuyi
Subjects: *DATA transmission systems, *ANTENNAS (Electronics), *DYNAMIC programming, *EARTH stations, *COORDINATES, *TELECOMMUNICATION satellites
Abstract: This paper investigates the mission planning problem of an agile satellite equipped with a two-dimensional antenna pointing mechanism. Multiple relay satellites and ground stations are included into the scenario to ensure the real-time data downlink. Therefore, to achieve the optimal real-time data transmission performance, two optimization modes are proposed in this paper to generate the slew path for both the satellite base and the antenna pointing mechanism. First, a baseline attitude coordinate system is introduced to efficiently handle the constraint of the problem. Second, the decoupled method is presented based on the two-level optimization strategy, which combines the genetic algorithm and the artificial potential method. Third, the dynamic programming concept is introduced to generate the optimal slew path by multi-body control approach. Simulation results show that the proposed algorithms can properly circumvent the complex mission planning problem, and that the maximum real-time data downlink can be established while ensuring the complete coverage of the target area. [ABSTRACT FROM AUTHOR]
Published: 2019
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13. Hierarchical scheduling for real-time agile satellite task scheduling in a dynamic environment.

Author: He, Lei, Liu, Xiao-Lu, Chen, Ying-Wu, Xing, Li-Ning, and Liu, Ke
Subjects: *AGILE software development, *COMPUTER scheduling, *MOTHERBOARDS, *GLOBAL environmental change, *TIME delay systems
Abstract: Highlights • We study the problem of agile satellite scheduling with real-time cloud coverage. • A hierarchical scheduling model is established. • A hierarchical scheduling algorithm based on the ant colony algorithm is proposed. • The influence of environmental changes is well-mitigated by the proposed method. • The proposed method can greatly reduce the CPU time and increase the total profit. Abstract The imaging processes of optical satellites can be easily affected by unexpected environmental changes, such as changes in cloud coverage. Given the difficulty to predict environmental uncertainties, traditional offline scheduling methods need a follow-up re-scheduling process that responds to real-time environmental information. This repetitive scheduling processes make the offline fine scheduling process a waste of computational resources. Additionally, the offline scheduling method is quite complex owing to its lack of a hierarchy mechanism. To solve these problems, we propose a hierarchical scheduling method for the real-time scheduling problem. This method divides the scheduling process into three steps: pre-assignment, rough scheduling, and fine scheduling. A hierarchical scheduling algorithm based on ant colony algorithm is proposed. Tests with 36 scenarios show that the calculation time is efficiently reduced with this new mechanism. With this consideration of the dynamic environment, the re-scheduling process becomes unnecessary, meaning the wasting of computational resources is avoided and the solution profit is improved. [ABSTRACT FROM AUTHOR]
Published: 2019
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14. Task allocation strategies for cooperative task planning of multi-autonomous satellite constellation.

Author: Yao, Feng, Li, Jiting, Chen, Yuning, Chu, Xiaogeng, and Zhao, Bang
Subjects: *ARTIFICIAL satellites, *SUPPORT vector machines, *SIMULATION methods & models, *COMPUTER scheduling, *MULTIVARIATE analysis
Abstract: Abstract In recent years, the application of imaging satellites has entered a completely new stage, with the new demands such as rapid response to emergency events, observation of large-scale regional targets and multivariate data fusion, the multi-autonomous satellite constellation has been proposed. This paper first designs the structure of multi-autonomous satellite constellation, and a centralized-distributed structure is proposed. This structure could improve the dynamic response capacity of the whole constellation. Then, this paper adds adapted filtering mechanism to single autonomous satellite online scheduling algorithm to enhance its performance. This article also pays more attention on task allocation strategies of the master satellite in constellation, and ten different task allocation strategies based on five dimensions are analyzed by simulation experiments. At last, this paper extracts several characteristic features of the regular observation targets and designs a selector based on support vector machine (SVM). This selector could select an appropriate strategy according to the features of each experiment scenario. [ABSTRACT FROM AUTHOR]
Published: 2019
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15. Multi-objective optimization of agile satellite orbit design.

Author: Song, Zhiming, Chen, Xiaoyu, Luo, Xin, Wang, Maocai, and Dai, Guangming
Subjects: *MULTIPLE criteria decision making, *ORBITS of artificial satellites, *EARTH'S orbit, *GEOPOTENTIAL height, *SPATIOTEMPORAL processes
Abstract: Highlights • A realistic repeating ground track orbit of agile satellite is investigated. • The variation of all feasible solutions over orbital parameters is analyzed. • A multi-objective optimization technique for optimal orbit design is proposed. • Results demonstrate the validity and effectiveness of the proposed technique. Abstract Satellite orbit design is a fundamental and important task during the mission analysis and the agile satellite design. In this paper we first investigate the design of a more realistic repeating ground track orbit in an accurate geopotential model of Earth. Furthermore, by considering the view field of the resource equipped on an agile satellite, we calculate the variation of the orbital altitude, the tilt angle, and the off-nadir resolution with the desired revisit time. Additionally, we analyze the distribution of all feasible solutions. In considering the spatial resolution and temporal resolution simultaneously, we propose a multi-objective optimization technique for optimal feasible orbits generation. Finally, through various case studies, the application of multi-objective optimization in orbit design of agile satellite is successfully demonstrated. Results also illustrate the validity and effectiveness of the proposed technique. [ABSTRACT FROM AUTHOR]
Published: 2018
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16. Design, Manufacturing and Test of a Three Degrees-of-Freedom Attitude Control Simulator for an Agile Micro-Satellite Based on Single Gimbal Control Moment Gyros

Author: A.R. Aghalari, A. Kalhor, S. M. M. Dehghan, and S. H. Cheheltani
Subjects: simulator, agile satellite, attitude control, single, gimbal control moment gyro, air bearing, Technology, Astronomy, QB1-991
Abstract: The Agile Satellite Attitude Control System Simulator (ASACSS) is a laboratory system designed for the purpose of developing and testing attitude control algorithms in a low-risk, low-cost environment. In this paper, the design and development of the ASACSS is described, including hardware and software. There are many papers that present a new mathematical technique or prove a new theory, but this study presents the design and development of a new experimental system. This simulator consists of four main components: 1) power supply system 2) on-board control system 3) supporting equipments and 4) monitoring computer. On-board control system includes a industrial computer, four single gimbal control moment gyros and a sensor for attitude determination. Supporting equipments include a platform for installing simulator subsystems, a semi-spherical air bearing and a pedestal. A high-speed wireless LAN connection enables remote command initiation, monitoring and data collection for post-experimental analysis. In this paper, The design and construction process of the simulator are described. More over some experimental results presented from the application of a simple PID attitude controller on the spacecraft simulator. Finally, experimental results are compared with those obtained from simulation.
Published: 2014

17. Onboard mission planning for agile satellite using modified mixed-integer linear programming.

Author: She, Yuchen, Li, Shuang, and Zhao, Yanbin
Subjects: *INTEGERS, *LINEAR programming, *COMBINATORIAL optimization, *GENETIC algorithms, *REAL-time control
Abstract: This paper investigates a new Agile Earth Observation Satellite (AEOS) mission planning algorithm. This new developed algorithm is based on Modified Mixed-Integer Linear Programming (MILP) approach, which takes the minimum slew angle and highest priority criterion. The key point of the paper lies in that the planning process is treated as a Dynamical Combinatorial Optimization (DCO) problem due to the time-varying constraint and the requirement of the problem. The design of the new algorithm is also to meet the real-time requirement of onboard mission planning. The mathematical formulation of the problem is modified to satisfy the demand of the LP solver, and a newly developed dynamic database is used to simulate the constantly changing satellite-target relative position with limited observation windows. The new mission planning model is solved by the LP method to test its reliability. Another solution with Generic Algorithm (GA) is also given to check the result. The calculation time of these two methods is compared to show that the LP approach has a better compatibility with the onboard mission planning requirement. [ABSTRACT FROM AUTHOR]
Published: 2018
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18. 面向新颖成像模式敏捷卫星的联合执行机构控制方法.

Author: 范国伟, 常琳, 杨秀彬, 王旻, and 王绍举
Abstract: Copyright of Acta Automatica Sinica is the property of Chinese Academy of Sciences, Institute of Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Published: 2017
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19. The 3rd AGILE Terrestrial Gamma Ray Flash Catalog. Part I: Association to Lightning Sferics

Author: M. Galli, C. Pittori, F. Verrecchia, David Sarria, Anders Lindanger, Nikolai Østgaard, C. Maiorana, Kjetil Albrechtsen, A. Ursi, Claudio Labanti, Martino Marisaldi, Marco Tavani, Lindanger, A., Marisaldi, M., Maiorana, C., Sarria, D., Albrechtsen, K., Ostgaard, N., Galli, M., Ursi, A., Labanti, C., Tavani, M., Pittori, C., and Verrecchia, F.
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, business.industry, terrestrial electron beam, Radio atmospheric, 01 natural sciences, Lightning, atmospheric electricity, terrestrial gamma ray flash, Geophysics, Word Wide Lightning Location Network, Space and Planetary Science, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), AGILE satellite, Environmental science, Atmospheric electricity, lightning, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Terrestrial gamma-ray flash, Agile software development
Abstract: We present a complete and systematic search for terrestrial gamma-ray flashes (TGFs), detected by AGILE, that are associated with radio sferics detected by the World Wide Lightning Location Network (WWLLN) in the period February 2009 to September 2018. The search algorithms and characteristics of these new TGFs will be presented and discussed. The number of WWLLN identified (WI) TGFs shows that previous TGF selection criteria needs to be reviewed as they do not identify all the WI TGFs in the data set. In this analysis we confirm with an independent data set that WI TGFs tend to have shorter time duration than TGFs without a WWLLN match. TGFs occurs more often on coastal and ocean regions compared to the distribution of lightning activity. Several multipulse TGFs were identified and their WWLLN match are always associated with the last gamma-ray pulse. We also present the first Terrestrial Electron Beam detected by AGILE. This data set together with the TGF sample identified by selection criteria (companion paper Maiorana et al., 2020) constitute the 3rd AGILE TGF catalog. publishedVersion
Published: 2020

20. Selecting and scheduling observations of agile satellites

Author: Lemaıtre, Michel, Verfaillie, Gérard, Jouhaud, Frank, Lachiver, Jean-Michel, and Bataille, Nicolas
Subjects: *ARTIFICIAL satellites, *SURFACE of the earth
Abstract: This article concerns the problem of managing the new generation of Agile Earth Observing Satellites (AEOS). This kind of satellites is presently studied by the French Centre National d'E´tudes Spatiales (PLEIADES project). The mission of an Earth Observing Satellite is to acquire images of specified areas on the Earth surface, in response to observation requests from customers. Whereas non-agile satellites such as SPOT5 have only one degree of freedom for acquiring images, the new generation satellites have three, giving opportunities for a more efficient use of the satellite imaging capabilities. Counterwise to this advantage, the selection and scheduling of observations becomes significantly more difficult, due to the larger search space for potential solutions. Hence, selecting and scheduling observations of agile satellites is a highly combinatorial problem. This article sets out the overall problem and analyses its difficulties. Then it presents different methods which have been investigated in order to solve a simplified version of the complete problem: a greedy algorithm, a dynamic programming algorithm, a constraint programming approach and a local search method. [Copyright &y& Elsevier]
Published: 2002

21. On the High‐Energy Spectral Component and Fine Time Structure of Terrestrial Gamma Ray Flashes

Author: Alessio Trois, Martino Marisaldi, Marco Tavani, Nikolai Østgaard, David Sarria, Riccardo Campana, A. Ursi, Fanchao Lyu, Steven A. Cummer, C. Pittori, Anders Lindanger, M. Galli, F. Verrecchia, C. Labanti, A. Argan, F. Fuschino, ITA, USA, NOR, Marisaldi, M., Galli, M., Labanti, C., Ostgaard, N., Sarria, D., Cummer, S. A., Lyu, F., Lindanger, A., Campana, R., Ursi, A., Tavani, M., Fuschino, F., Argan, A., Trois, A., Pittori, C., and Verrecchia, F.
Subjects: Atmospheric Science, Photon, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, FOS: Physical sciences, Astrophysics, 7. Clean energy, 01 natural sciences, Spectral line, atmospheric electricity, Physics - Space Physics, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), high-energy atmospheric physics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, high-energy atmospheric physic, Gamma ray, Spectral component, AGILE satellite, high-energy radiation, lightning, terrestrial gamma ray flash, Lightning, Space Physics (physics.space-ph), Particle acceleration, Geophysics, Relativistic runaway electron avalanche, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Terrestrial gamma ray flashes (TGFs) are very short bursts of gamma radiation associated to thunderstorm activity and are the manifestation of the highest-energy natural particle acceleration phenomena occurring on Earth. Photon energies up to several tens of megaelectronvolts are expected, but the actual upper limit and high-energy spectral shape are still open questions. Results published in 2011 by the AGILE team proposed a high-energy component in TGF spectra extended up to $\approx$100 MeV, which is difficult to reconcile with the predictions from the Relativistic Runaway Electron Avalanche (RREA) mechanism at the basis of many TGF production models. Here we present a new set of TGFs detected by the AGILE satellite and associated to lightning measurements capable to solve this controversy. Detailed end-to-end Monte Carlo simulations and an improved understanding of the instrument performance under high-flux conditions show that it is possible to explain the observed high-energy counts by a standard RREA spectrum at the source, provided that the TGF is sufficiently bright and short. We investigate the possibility that single high-energy counts may be the signature of a fine-pulsed time structure of TGFs on time scales $\approx$4 {\mu}s, but we find no clear evidence for this. The presented data set and modeling results allow also for explaining the observed TGF distribution in the (Fluence x duration) parameter space and suggest that the AGILE TGF detection rate can almost be doubled. Terrestrial gamma ray flashes (TGFs) are very short bursts of gamma radiation associated to thunderstorm activity and are the manifestation of the highest-energy natural particle acceleration phenomena occurring on Earth. (...continues)
Published: 2019

22. THE 2009 DECEMBER GAMMA-RAY FLARE OF 3C 454.3: THE MULTIFREQUENCY CAMPAIGN

Author: L. Salotti, E. Moretti, Mark Gurwell, C. Pittori, M. Tavani, S. Vercellone, V. Vittorini, F. Longo, T. Sakamoto, Martino Marisaldi, A. Morselli, M. Galli, P. Santolamazza, G. Barbiellini P. Caraveo, Elena Pian, C. M. Raiteri, M. Pilia, Francesco Lucarelli, A. Trois, A. Rubini, F. D'Ammando, F. Verrecchia, Michael C. Stroh, M. Prest, F. Perotti, Andrea Tiengo, E. Vallazza, P. W. Cattaneo, M. Feroci, Merja Tornikoski, M. Villata, L. Pacciani, P. Picozza, A. Pellizzoni, E. Costa, E. Del Monte, A. Rappoldi, M. Fiorini, Ryosuke Itoh, P. A. Curran, Masayuki Yamanaka, G. Pucella, F. Lazzarotto, Valeri M. Larionov, C. S. Lin, F. Gianotti, A. C. Sadun, A. Giuliani, V. Cocco, Arnaud Ferrari, P. Lipari, M. Trifoglio, M. Fiocchi, E. Morelli, Andrei Berdyugin, G. Piano, H. A. Krimm, Sandro Mereghetti, L. O. Takalo, A. D. Falcone, S. Colafrancesco, Claudio Labanti, D. Zanello, F. Fuschino, D. Fugazza, G. Di Cocco, M. Rapisarda, A. Argan, Andrea Bulgarelli, Makoto Uemura, P. Giommi, Anne Lähteenmäki, G. De Paris, I. Donnarumma, Y. Evangelista, P. Soffitta, A. W. Chen, Paolo Leto, Hugh D. Aller, E. Striani, Mahito Sasada, I. Lapshov, M. F. Aller, S. Sabatini, Pacciani L, Vittorini V, Tavani M, Fiocchi MT, Vercellone S, DAmmando F, Sakamoto T, Pian E, Raiteri CM, Villata M, Sasada M, Itoh R, Yamanaka M, Uemura M, Striani E, Fugazza D, Tiengo A, Krimm HA, Stroh MC, Falcone AD, Curran PA, Sadun AC, Lahteenmaki A, Tornikoski M, Aller HD, Aller MF, Lin CS, Larionov VM, Leto P, Takalo LO, Berdyugin A, Gurwell MA, Bulgarelli A, Chen AW, Donnarumma I, Giuliani A, Longo F, Pucella G, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, 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, Colafrancesco S, Pittori C, Verrecchia F, Santolamazza P, Lucarelli F, Giommi P, Salotti L, L., Pacciani, V., Vittorini, M., Tavani, M. T., Fiocchi, S., Vercellone, F., D'Ammando, T., Sakamoto, E., Pian, C. M., Raiteri, M., Villata, M., Sasada, R., Itoh, M., Yamanaka, M., Uemura, E., Striani, D., Fugazza, A., Tiengo, H. A., Krimm, M. C., Stroh, A. D., Falcone, P. A., Curran, A. C., Sadun, A., Lahteenmaki, M., Tornikoski, H. D., Aller, M. F., Aller, C. S., Lin, V. M., Larionov, P., Leto, L. O., Takalo, A., Berdyugin, M. A., Gurwell, A., Bulgarelli, A. W., Chen, I., Donnarumma, A., Giuliani, Longo, Francesco, G., Pucella, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, E., Costa, G. D., Pari, E. D., Monte, G. D., Cocco, Y., Evangelista, A., Ferrari, M., Feroci, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, D., Zanello, S., Colafrancesco, C., Pittori, F., Verrecchia, P., Santolamazza, F., Lucarelli, P., Giommi, and L., Salotti
Subjects: Agile, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, galaxies: active, Flux, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, gamma-ray source, High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, Spectral line, blazar, law.invention, Accretion disc, multi wavelength observation, law, quasars: general, Blazar, media_common, Physics, galaxies: individual (3C 454.3), Gamma ray, Astronomy and Astrophysics, radiation mechanisms: non-thermal, Wavelength, Space and Planetary Science, Sky, Flare
Abstract: During the month of 2009 December, the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F 2000 × 10 -8 photons cm-2 s-1 for E > 100 MeV. Starting in 2009 November intensive multifrequency campaigns monitored the 3C 454 gamma-ray outburst. Here, we report on the results of a two-month campaign involving AGILE, INTEGRAL, Swift/XRT, Swift/BAT, and Rossi XTE for the high-energy observations and Swift/UVOT, KANATA, Goddard Robotic Telescope, and REM for the near-IR/optical/UV data. GASP/WEBT provided radio and additional optical data. We detected a long-term active emission phase lasting 1 month at all wavelengths: in the gamma-ray band, peak emission was reached on 2009 December 2-3. Remarkably, this gamma-ray super-flare was not accompanied by correspondingly intense emission in the optical/UV band that reached a level substantially lower than the previous observations in 2007-2008. The lack of strong simultaneous optical brightening during the super-flare and the determination of the broadband spectral evolution severely constrain the theoretical modeling. We find that the pre- and post-flare broadband behavior can be explained by a one-zone model involving synchrotron self-Compton plus external Compton emission from an accretion disk and a broad-line region. However, the spectra of the 2009 December 2-3 super-flare and of the secondary peak emission on 2009 December 9 cannot be satisfactorily modeled by a simple one-zone model. An additional particle component is most likely active during these states. © 2010. The American Astronomical Society. All rights reserved.
Published: 2010
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23. Long-term AGILE monitoring of the puzzling gamma-ray source 3EG J1835+5918

Author: G. De Paris, A. Zambra, F. D'Ammando, M. Feroci, M. Fiorini, Dario Gasparrini, L. Pacciani, F. Longo, A. Rappoldi, E. Vallazza, F. Boffelli, M. Rapisarda, P. Picozza, A. Argan, F. Perotti, E. Del Monte, G. Pucella, A. Trois, Andrea Bulgarelli, I. Donnarumma, T. Froysland, P. Soffitta, A. Pellizzoni, Guido Barbiellini, Enrico Costa, Y. Evangelista, F. Lazzarotto, V. Vittorini, V. Cocco, P. Santolamazza, M. Trifoglio, A. Giuliani, Paolo Lipari, A. W. Chen, P. Giommi, F. Fuschino, S. Vercellone, C. Pittoril, M. Galli, F. Verrecchia, Martino Marisaldi, Sandro Mereghetti, P. W. Cattaneo, P. A. Caraveo, I. Lapshov, M. Prest, S. Colafrancesco, Marco Tavani, G. Piano, A. Morselli, Claudio Labanti, L. Salotti, D. Zanello, M. Marelli, G. Di Cocco, S. Cutini, Fulvio Gianotti, Bulgarelli A, Tavani M, Caraveo P, Chen AW, Gianotti F, Trifoglio M, Marelli M, Argan A, Barbiellini G, Boffelli F, Cattaneo PW, Cocco V, Costa E, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Donnarumma I, Evangelista Y, Feroci M, Fiorini M, Froysland T, Fuschino F, Galli M, 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, Prest M, Pucella G, Rapisarda M, Rappoldi A, Soffitta P, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Giommi P, Pittori C, Verrecchia F, Santolamazza P, Gasparrini D, Cutini S, Colafrancesco S, Salotti L, A., Bulgarelli, M., Tavani, P., Caraveo, A. W., Chen, F., Gianotti, M., Trifoglio, M., Marelli, A., Argan, G., Barbiellini, F., Boffelli, P. W., Cattaneo, V., Cocco, E., Costa, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, I., Donnarumma, Y., Evangelista, M., Feroci, M., Fiorini, T., Froysland, F., Fuschino, M., Galli, A., Giuliani, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, S., Mereghetti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, P., Soffitta, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, P., Giommi, C., Pittori, F., Verrecchia, P., Santolamazza, D., Gasparrini, S., Cutini, S., Colafrancesco, and L., Salotti
Subjects: Photon, Field (physics), FOS: Physical sciences, Flux, Field of view, Astrophysics, Unidentified Gamma-ray Source, Power law, High Energy Gamma-ray Astronomy, AGILE gamma ray satellite, 3EG J1835+5918, Egret, Physics, biology, Astrophysics (astro-ph), Gamma ray, Astronomy and Astrophysics, biology.organism_classification, Term (time), Space and Planetary Science, Unidentified Gamma-ray Sources, AGILE satellite, gamma rays: observations
Abstract: We present the AGILE gamma-ray observations of the field containing the puzzling gamma-ray source 3EG J1835+5918. This source is one of the most remarkable unidentified EGRET sources. An unprecedentedly long AGILE monitoring of this source yields important information on the positional error box, flux evolution, and spectrum. 3EG J1835+5918 has been in the AGILE field of view several times in 2007 and 2008 for a total observing time of 138 days from 2007 Sept 04 to 2008 June 30 encompassing several weeks of continuous coverage. With an exposure time approximately twice that of EGRET, AGILE confirms the existence of a prominent gamma-ray source (AGL J1836+5926) at a position consistent with that of EGRET, although with a remarkably lower average flux value for photon energies greater than 100 MeV. A 5-day bin temporal analysis of the whole data set of AGL J1836+5926 shows some evidence for variability of the gamma-ray flux. The source spectrum between 100 MeV and 1 GeV can be fitted with a power law with photon index in the range 1.6-1.7, fully consistent with the EGRET value. The faint X-ray source RX J1836.2+5925 that has been proposed as a possible counterpart of 3EG J1835+5918 is well within the AGILE error box. Future continuous monitoring (both by AGILE and GLAST) is needed to confirm the gamma-ray flux variability and to unveil the source origin, a subject that is currently being pursued through a multiwavelength search for counterparts., Comment: accepted for publication by Astron. & Astrophys, 4 pages, 2 figures, 2 tables
Published: 2008
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24. The AGILE space mission

Author: Francesco Longo, V. Cocco, M. Trifoglio, Ennio Morelli, Alda Rubini, Sandro Mereghetti, F. Perotti, P. A. Caraveo, A. Zambra, E. Rossi, C. Pittori, G. Di Cocco, T. Froysland, M. Galli, Martino Marisaldi, F. Fuschino, M. Fiorini, Paolo Soffitta, G. De Paris, G. Barbiellini, Marco Feroci, Luigi Pacciani, A. Morselli, F. Mauri, I. Lapshov, E. Del Monte, G. Pucella, Marco Tavani, Massimo Rapisarda, M. Mastropietro, M. Prest, Claudio Labanti, Paolo Lipari, S. Vercellone, D. Zanello, E. Vallazza, Angelo Antonelli, C. Pontoni, A. W. Chen, P. Giommi, A. Argan, Andrea Bulgarelli, Enrico Costa, Fulvio Gianotti, Alessio Trois, Geiland Porrovecchio, Francesco Lazzarotto, I. Donnarumma, P. Picozza, A. Pellizzoni, A. Giuliani, Y. Evangelista, M., Tavani, G., Barbiellini, A., Argan, A., Bulgarelli, P., Caraveo, A., Chen, V., Cocco, E., Costa, G. D., Pari, E. D., Monte, G. D., Cocco, I., Donnarumma, M., Feroci, M., Florini, T., Froysland, F., Fuschino, M., Galli, F., Gianotti, A., Giuliani, Y., Evangelista, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, M., Mastropietro, F., Mauri, S., Mereghetti, E., Morelli, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, C., Pontoni, G., Porrovecchio, M., Prest, G., Pucella, M., Rapisarda, E., Rossi, A., Rubini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, S., Vercellone, A., Zarnbra, D., Zanello, P., Giommi, A., Antonelli, and C., Pittori
Subjects: Physics, Nuclear and High Energy Physics, Active galactic nucleus, silicon tungsten tracker, business.industry, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Detector, Astronomy, Detectors, Space (commercial competition), small mission, High Energy Gamma-ray Astronomy, Universe, Supernova, Orbit (dynamics), AGILE satellite, Angular resolution, business, Instrumentation, Agile software development, media_common
Abstract: AGILE is an Italian Space Agency mission dedicated to the exploration of the gamma-ray Universe. The AGILE, very innovative instrument, combines for the first time a gamma-ray imager (sensitive in the range 30 MeV–50 GeV) and a hard X-ray imager (sensitive in the range 18–60 keV). An optimal angular resolution and very large fields of view are obtained by the use of state-of-the-art Silicon detectors integrated in a very compact instrument. AGILE was successfully launched on April 23, 2007 from the Indian base of Sriharikota and was inserted in an optimal low-particle background equatorial orbit. AGILE will provide crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, unidentified gamma-ray sources, galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. The AGILE Cycle-1 pointing program started on 2007 December 1, and is open to the international community through a Guest Observer Program.
Published: 2008
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25. AGILE Detection of a Strong Gamma-Ray Flare from the Blazar 3C 454.3

Author: T. Froysland, Martino Marisaldi, G. De Paris, Dario Gasparrini, Fulvio Gianotti, F. Perotti, F. Mauri, L. Salotti, A. Zambra, M. Prest, S. Cutini, Francesco Longo, G. Di Cocco, Paolo Giommi, Francesco Lazzarotto, M. Galli, Piergiorgio Picozza, Paolo Soffitta, F. Verrecchia, Marco Tavani, A. Pellizzoni, D. Zanello, Massimo Rapisarda, Claudio Labanti, Alessio Trois, Sergio Colafrancesco, L. A. Antonelli, P. A. Caraveo, Sandro Mereghetti, A. Giuliani, S. Vercellone, M. Fiorini, I. Donnarumma, Guido Barbiellini, A. Morselli, F. D'Ammando, Y. Evangelista, Marco Feroci, Luigi Pacciani, Paolo Lipari, E. Vallazza, F. Fuschino, V. Cocco, V. Vittorini, E. Del Monte, M. Trifoglio, G. Pucella, I. Lapshov, A. Argan, Andrea Bulgarelli, Enrico Costa, A. W. Chen, C. Pittori, S., Vercellone, A. W., Chen, A., Giuliani, A., Bulgarelli, I., Donnarumma, I., Lapshov, M., Tavani, A., Argan, G., Barbiellini, P., Caraveo, V., Cocco, E., Costa, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, Y., Evangelista, M., Feroci, M., Fiorini, T., Froysland, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, F., Lazzarotto, P., Lipari, Longo, Francesco, M., Marisaldi, F., Mauri, S., Mereghetti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Prest, G., Pucella, M., Rapisarda, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, D., Gasparrini, S., Cutini, P., Giommi, L. A., Antonelli, S., Colafrancesco, L., Salotti, Vercellone S, Chen AW, Giuliani A, Bulgarelli A, Donnarumma I, Lapshov I, Tavani M, Argan A, Barbiellini G, Caraveo P, Cocco V, Costa E, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Evangelista Y, Feroci M, Fiorini M, Froysland T, Fuschino F, Galli M, Gianotti F, Labanti C, Lazzarotto F, Lipari P, Longo F, Marisaldi M, Mauri F, Mereghetti S, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Prest M, Pucella G, Rapisarda M, Soffitta P, Trifoglio M, Trois A, Vallazza E, Vittorini V, Zambra A, Zanello D, Pittori C, Verrecchia F, Gasparrini D, Cutini S, Giommi P, Antonelli LA, Colafrancesco S, and Salotti L
Subjects: High Energy Gamma-ray Astronomy, Active Galactic Nuclei, AGILE satellite, Agile, Photon, blazar, gamma and X-ray detection, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, law.invention, astro-ph, law, Blazar, Physics, Range (particle radiation), Astrophysics (astro-ph), Detector, Gamma ray, Astronomy and Astrophysics, Quasar, Space and Planetary Science, gamma rays: observations — quasars: individual (3C 454.3), Energy (signal processing), Flare
Abstract: We report the first blazar detection by the AGILE satellite. AGILE detected 3C 454.3 during a period of strongly enhanced optical emission in July 2007. AGILE observed the source with a dedicated repointing during the period 2007 July 24-30 with its two co-aligned imagers, the Gamma-Ray Imaging Detector and the hard X-ray imager Super-AGILE sensitive in the 30 MeV-50 GeV and 18-60 keV, respectively. Over the entire period, AGILE detected gamma-ray emission from 3C 454.3 at a significance level of 13.8-$\sigma$ with an average flux (E$>$100 MeV) of $(280 \pm 40) \times 10^{-8}$ photons cm$^{-2}$ s$^{-1}$. The gamma-ray flux appears to be variable towards the end of the observation. No emission was detected by Super-AGILE in the energy range 20-60 keV, with a 3-$\sigma$ upper limit of $2.3 \times 10^{-3}$ photons cm$^{-2}$ s$^{-1}$. The gamma-ray flux level of 3C 454.3 detected by AGILE is the highest ever detected for this quasar and among the most intense gamma-ray fluxes ever detected from Flat Spectrum Radio Quasars., Comment: Accepted by Astrophysical Journal Letters; 14 pages, 3 EPS Figures, 1 Table
Published: 2008
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26. Search of MeV-GeV counterparts of TeV Sources

Author: A. Rappoldi, Francesco Longo, C. Pittori, P. W. Cattaneo, F. Verrecchia, Fabrizio Lucarelli, F. Giovannelli and L. Sabau-Graziati, Pittori, C., Rappoldi, A., Lucarelli, F., Cattaneo, P. W., Longo, F., Verrecchia, F., and ITA
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Observation period, gamma-ray astrophysic, Astrophysics, TeV sources, gamma-ray astrophysics, AGILE satellite, Sky, Satellite, media_common, Systematic search
Abstract: We present the results of a systematic search for gamma-ray emission from known and unidentified TeV sources, using the data collected by the AGILE satellite in observing pointing mode in the energy range above 100 MeV. We found that $\sim 34\% $ of the analysed TeV sources sample, extracted from the online TeVCat catalog, show a significant excess in the AGILE data collected during the pointing observation period, from July 9, 2007 to October 18, 2009. We plan to extend this analysis also to the AGILE data collected from November 2009 on, obtained by observing each day a large portion of the sky in spinning mode.
Published: 2016

27. GRB 070724B: the first gamma ray burst localized by SuperAGILE and its Swift X-ray afterglow

Author: F. Mauri, Marco Feroci, Luigi Pacciani, P. Lipari, M. Galli, Piergiorgio Picozza, Massimo Rapisarda, A. Argan, Andrea Bulgarelli, L. A. Antonelli, Claudio Labanti, Enrico Costa, F. Verrecchia, B. Preger, P. A. Caraveo, Neil Gehrels, V. Vittorini, E. Vallazza, M. Trifoglio, E. Del Monte, C. Pittori, A. Pellizzoni, P. Romano, S. Vercellone, F. Perotti, A. Giuliani, G. Di Cocco, L. Salotti, A. Zambra, J. P. Osborne, David N. Burrows, L. Foggetta, M. Prest, I. Lapshov, Alessio Trois, Paolo Soffitta, M. Basset, Sandro Mereghetti, Francesco Lazzarotto, Y. Evangelista, V. La Parola, Martino Marisaldi, P. T. O'Brien, G. Chincarini, Marco Tavani, I. Donnarumma, A. W. Chen, Fulvio Gianotti, F. Fuschino, A. Morselli, G. Barbiellini, Paolo Giommi, Francesco Longo, G. Pucella, DEL MONTE, E, Feroci, M, Pacciani, L, Evangelista, Y, Donnarumma, I, Soffitta, P, Costa, E, Lapshov, I, Lazzarotto, F, Rapisarda, M, Argan, A, BARBIELLINI AMIDEI, Guido, Basset, M, Bulgarelli, A, Caraveo, P, Chen, A, DI COCCO, G, Foggetta, L, Fuschino, F, Galli, M, Gianotti, F, Giuliani, A, Labanti, C, Lipari, P, Longo, Francesco, Marisaldi, M, Mauri, F, Mereghetti, S, Morselli, A, Pellizzoni, A, Perotti, F, Picozza, P, Prest, M, Pucella, G, Tavani, M, Trifoglio, M, Trois, A, Vallazza, E, Vercellone, S, Vittorini, V, Zambra, A, Romano, P, BURROWS D., N, Chincarini, G, Gehrels, N, LA PAROLA, V, O'BRIEN P., T, OSBORNE J., P, Preger, B, Pittori, C, ANTONELLI L., A, Verrecchia, F, Giommi, P, and Salotti, L.
Subjects: Physics, Swift, Very large array, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), X-ray, Gamma ray, FOS: Physical sciences, AGILE satellite, GRB 070724B, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, law.invention, Afterglow, Telescope, Space and Planetary Science, law, Gamma-ray burst, computer, computer.programming_language
Abstract: GRB 070724B is the first Gamma Ray Burst localized by SuperAGILE, the hard X-ray monitor aboard the AGILE satellite. The coordinates of the event were published $\sim 19$ hours after the trigger. The Swift X-Ray Telescope pointed at the SuperAGILE location and detected the X-ray afterglow inside the SuperAGILE error circle. The AGILE gamma-ray Tracker and Minicalorimeter did not detect any significant gamma ray emission associated with GRB 070724B in the MeV and GeV range, neither prompt nor delayed. Searches of the optical afterglow were performed by the Swift UVOT and the Palomar automated 60-inch telescopes without any significant detection. Similarly the Very Large Array did not detect a radio afterglow. This is the first GRB event with a firm upper limit in the 100 MeV -- 30 GeV energy range, associated with an X-ray afterglow., Comment: 7 pages, 4 figures (of which 2 in color), contains online material. Accepted for publication by Astronomy & Astrophysics Letters
Published: 2007
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28. Building Flexible Download Plans for Agile Earth-Observing Satellites

Author: Maillard, A., Verfaillie, G., Pralet, C., Jaubert, J., Desmousceaux, T., André, Cécile, ONERA - The French Aerospace Lab [Toulouse], ONERA, Centre National d'Études Spatiales [Toulouse] (CNES), and Airbus Defence and Space
Subjects: AGILE SATELLITE, PLANNING, FLEXIBILITY, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], [PHYS.PHYS.PHYS-SPACE-PH] Physics [physics]/Physics [physics]/Space Physics [physics.space-ph]
Abstract: International audience; We consider the problem of downloading observa-tions for a next-generation agile Earth-observing satellite. The goal is to schedule file downloads during ground re-ception station visibility windows while minimizing infor-mation age and promoting the fair sharing of the satellite between users. It is a complex scheduling problem with constraints ranging from unsharable resources to time-dependent processing times. Usually, planning and sche-duling are done on the ground but in our case, data vo-lumes are unpredictable and we propose to share decision-making between the ground and the onboard software, which allows us to take decisions knowing the data vo-lume onboard while keeping a fair level of predictabi-lity on the ground. We develop several levels of flexibi-lity, a decision-making architecture and compare these ap-proaches on realistic scenarios.
Published: 2014

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

Author: F. Perotti, Ennio Morelli, Massimiliano Fiorini, Sandro Mereghetti, G. Valentini, P. W. Cattaneo, E. Moretti, C. Pittori, A. Rappoldi, V. Vittorini, P. Santolamazza, T. Contessi, G. De Paris, E. Vallazza, Francesco Longo, Fulvio Gianotti, I. Donnarumma, M. Trifoglio, A. Pellizzoni, M. Galli, Piergiorgio Picozza, M. Giusti, Alda Rubini, G. Piano, Paolo Giommi, A. Morselli, Y. Evangelista, F. Verrecchia, G. Di Cocco, Francesco Lazzarotto, E. Striani, Attilio Ferrari, Valentina Fioretti, Marco Tavani, S. Sabatini, Paolo Lipari, A. Argan, Maura Pilia, I. Lapshov, F. Lucarelli, Sergio Colafrancesco, Guido Barbiellini, E. Del Monte, Martino Marisaldi, G. Pucella, Massimo Rapisarda, Alessio Trois, F. Fuschino, Andrea Bulgarelli, M. Prest, D. Zanello, Enrico Costa, C. Labanti, A. Giuliani, P. A. Caraveo, A. W. Chen, S. Vercellone, Marco Feroci, Luigi Pacciani, Paolo Soffitta, Rapisarda, M., Pucella, G., Tadayuki Takahashi, Stephen S. Murray, Jan-Willem A. den Herder, A. W., Chen, A., Argan, A., Bulgarelli, P. W., Cattaneo, A., Giuliani, C., Pittori, G., Pucella, M., Tavani, A., Troi, G., Barbiellini, P., Caraveo, S., Colafrancesco, E., Costa, Paris, G., Monte, E., Cocco, G., I., Donnarumma, Y., Evangelista, A., Ferrari, M., Feroci, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, P., Giommi, M., Giusti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, F., Lucarelli, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Santolamazza, P., Soffitta, E., Striani, M., Trifoglio, L., Salotti, E., Vallazza, S., Vercellone, F., Verrecchia, V., Vittorini, D., Zanello, T., Contessi, BARBIELLINI AMIDEI, Guido, G., De Pari, E., Del Monte, G., Di Cocco, V., Fioretti, Moretti, Elena, and G., Valentini
Subjects: Photon, Monte Carlo method, X-ray telescope, techniques: image processing, Astrophysics, telescope, Orbital mechanics, Vela, High Energy Gamma-ray Astronomy, law.invention, law, imaging detector, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Instrumentation: detector, image processing [techniques], detector [instrumentation], Detector, agile, Astrophysics::Instrumentation and Methods for Astrophysics, Calibrations, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Interpolation, Point spread function, gamma ray source, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Telescope, Optics, data analysis [methods], Calibration, instrumentation: detectors, gamma rays: general, telescopes, methods: data analysis, Instrumentation and Methods for Astrophysics (astro-ph.IM), business.industry, Astronomy and Astrophysics, Kalman filter, calibration, silicon tracker, Computational physics, Space and Planetary Science, Gamma rays: general, Instrumentation: detectors, Methods: data analysis, Techniques: image processing, Telescopes, Orbit (dynamics), AGILE satellite, business, general [gamma rays], Methods: data analysi
Abstract: Context: AGILE is a gamma-ray astrophysics mission which has been in orbit since 23 April 2007 and continues to operate reliably. The gamma-ray detector, AGILE-GRID, has observed Galactic and extragalactic sources, many of which were collected in the first AGILE Catalog. Aims: We present the calibration of the AGILE-GRID using in-flight data and Monte Carlo simulations, producing Instrument Response Functions (IRFs) for the effective area A_eff), Energy Dispersion Probability (EDP), and Point Spread Function (PSF), each as a function of incident direction in instrument coordinates and energy. Methods: We performed Monte Carlo simulations at different gamma-ray energies and incident angles, including background rejection filters and Kalman filter-based gamma-ray reconstruction. Long integrations of in-flight observations of the Vela, Crab and Geminga sources in broad and narrow energy bands were used to validate and improve the accuracy of the instrument response functions. Results: The weighted average PSFs as a function of spectra correspond well to the data for all sources and energy bands. Conclusions: Changes in the interpolation of the PSF from Monte Carlo data and in the procedure for construction of the energy-weighted effective areas have improved the correspondence between predicted and observed fluxes and spectra of celestial calibration sources, reducing false positives and obviating the need for post-hoc energy-dependent scaling factors. The new IRFs have been publicly available from the Agile Science Data Centre since November 25, 2011, while the changes in the analysis software will be distributed in an upcoming release.
Published: 2013

30. The characterization of the distant blazar GB6 J1239+0443 from flaring and low activity periods

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

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. High spatial resolution correlation of AGILE TGFs and global lightning activity above the equatorial belt

Author: Fuschino F, Marisaldi M, Labanti C, Barbiellini G, Del Monte E, Bulgarelli A, Trifoglio M, Gianotti F, Galli M, Argan A, Trois A, Tavani M, Moretti E, Giuliani A, Longo F, Costa E, Caraveo P, Cattaneo PW, Chen A, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Lapshov I, Lazzarotto F, Lipari P, Mereghetti S, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Piano G, Pilia M, Prest M, Pucella G, Rapisarda M, Rappoldi A, Rubini A, Sabatini S, Soffitta P, Striani E, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Antonelli LA, Colafrancesco S, Cutini S, Giommi P, Lucarelli F, Pittori C, Santolamazza P, Verrecchia F, Salotti L., D'AMMANDO, FILIPPO, F., Fuschino, M., Marisaldi, C., Labanti, G., Barbiellini, Monte, E., A., Bulgarelli, M., Trifoglio, F., Gianotti, M., Galli, A., Argan, A., Troi, M., Tavani, E., Moretti, A., Giuliani, Longo, Francesco, E., Costa, P., Caraveo, P. W., Cattaneo, A., Chen, F., D'Ammando, Paris, G., Cocco, G., Persio, G., I., Donnarumma, Y., Evangelista, M., Feroci, A., Ferrari, M., Fiorini, I., Lapshov, F., Lazzarotto, P., Lipari, S., Mereghetti, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, G., Piano, M., Pilia, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Soffitta, E., Striani, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, L. A., Antonelli, S., Colafrancesco, S., Cutini, P., Giommi, F., Lucarelli, C., Pittori, P., Santolamazza, F., Verrecchia, L., Salotti, Fuschino F, Marisaldi M, Labanti C, Barbiellini G, Del Monte E, Bulgarelli A, Trifoglio M, Gianotti F, Galli M, Argan A, Trois A, Tavani M, Moretti E, Giuliani A, Longo F, Costa E, Caraveo P, Cattaneo PW, Chen A, DAmmando F, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Lapshov I, Lazzarotto F, Lipari P, Mereghetti S, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Piano G, Pilia M, Prest M, Pucella G, Rapisarda M, Rappoldi A, Rubini A, Sabatini S, Soffitta P, Striani E, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Antonelli LA, Colafrancesco S, Cutini S, Giommi P, Lucarelli F, Pittori C, Santolamazza P, Verrecchia F, and Salotti L
Subjects: AGILE satellite, terrestrial gamma ray flashes, CsI calorimeter, satellite optical observations, global lightning, Atmospheric Processes: Lightning, Lightning [Atmospheric Processes], Atmospheric Processes: Atmospheric electricity, AGILE, TGF, global lightning activity, Atmospheric electricity [Atmospheric Processes]
Abstract: The AGILE satellite detects Terrestrial Gamma-ray Flashes (TGFs) in the 0.35-100 MeV energy range using its Mini-Calorimeter (MCAL) instrument with an average detection rate of 10 TGFs/month. Thanks to its Low Earth Orbit with only 2.5 degree of inclination, AGILE guarantees an unprecedented exposure above the equator, where both lightning activity and TGF detection peak. Here we report the comparison between the AGILE TGFs detected between March 2009 and February 2010 and full climatology lightning worldwide distribution based on satellite optical observations from LIS (Lightning Imaging Sensor) and OTD (Optical Transient Detector) instruments. This approach is complementary to the one-to-one TGF/lightning correlations by ground-based sferics measurements. Based on mono and bi-dimensional Kolmogorov-Smirnov tests, we show that the AGILE TGFs and time-averaged global lightning in the equatorial area are not drawn from the same distribution. However, we find significant regional differences in the degree of correlation as well as in the TGF/lightning ratio. In the case of south east Asia we find a 87% probability for the TGF and lightning being samples of the same distribution. This result supports the idea that the physical conditions at play in TGF generation can have strong geographical and climatological modulation. Based on the assumption that the observed range of TGF/flash ratio holds at all latitudes we can estimate a global rate of (N) over dot similar or equal to 220 divided by 570 TGFs per day. The observed TGF/flash geographical modulation as well as the TGF global rate estimate are in agreement with previous observations. Citation: Fuschino, F., et al. (2011), High spatial resolution correlation of AGILE TGFs and global lightning activity above the equatorial belt, Geophys. Res. Lett., 38, L14806, doi:10.1029/2011GL047817.
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. The AGILE silicon tracker: Pre-launch and in-flight configuration

Author: L. Foggetta, M. Prest, F. Longo, G. Barbiellini, G. Di Cocco, F. Monzani, Marco Tavani, C. Pontoni, Sandro Mereghetti, G. Pucella, R. Pavesi, M. Basset, M. Trifoglio, E. Vallazza, L. Nicolini, S. Vercellone, A. Argan, Andrea Bulgarelli, A. W. Chen, Alessio Trois, Fulvio Gianotti, A. Pellizzoni, A. Giuliani, A., Bulgarelli, A., Argan, G., Barbiellini, M., Basset, A., Chen, G. D., Cocco, L., Foggetta, F., Gianotti, A., Giuliani, Longo, Francesco, S., Mereghetti, F., Monzani, L., Nicolini, R., Pavesi, A., Pellizzoni, C., Pontoni, M., Prest, G., Pucella, M., Tavani, M., Trifoglio, A., Troi, E., Vallazza, and S., Vercellone
Subjects: Nuclear and High Energy Physics, Photon, Silicon, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, satellite, chemistry.chemical_element, AGILE, silicon tracker, high energy gamma, High Energy Gamma-ray Astronomy, Optics, Data acquisition, AGILE satellite, Silicon Detectors, Angular resolution, Instrumentation, Physics, business.industry, Detector, Electrical engineering, Analog signal, chemistry, Orbit (dynamics), business, Energy (signal processing)
Abstract: AGILE is an ASI (Italian Space Agency) Small Scientific Mission dedicated to high-energy astrophysics which was successfully launched on April 23,2007. The AGILE instrument is composed of three main detectors: a Tungsten-Silicon Tracker designed to detect and image photons in the 30 MeV-50 GeV energy band, an X-ray imager called Super-AGILE operating in the 18-60 keV energy band, and a Mini-Calorimeter that detects gamma-rays and charged particles energy deposits between 300 key and 100 MeV. The instrument is surrounded by an anti-coincidence (AC) system. In this paper, we present the noise characterization and the front-end configuration of the Silicon Tracker. Two crucial (and unique, among gamma-ray astrophysics missions) characteristic of the AGILE Silicon Tracker are the analog signal acquisition (aimed at obtaining an optimal angular resolution for gamma-ray imaging) and the very small dimension of the instrument (the total height including the active elements is similar to 21 cm and therefore the Silicon Tracker is the lightest and most compact gamma-ray imager sent in orbit). The results presented in this paper were obtained during the AIV (Assembly. Integration and Verification) pre-launch testing phase and during the post-launch commissioning phase. The AGILE Silicon Tracker has been optimally configured with a very good response of the frontend system and of the data acquisition units. (C) 2010 Elsevier B.V. All rights reserved.
Published: 2010

37. Detection of terrestrial gamma ray flashes up to 40 MeV by the AGILE satellite

Author: Marisaldi, M., Fuschino, F., Labanti, C., Galli, M., Longo, Francesco, Monte, E. D., Barbiellini, G., Tavani, M., Giuliani, A., Moretti, E., Vercellone, S., Costa, E., Cutini, S., Donnarumma, I., Evangelista, Y., Feroci, M., Lapshov, I., Lazzarotto, F., Lipari, P., Mereghetti, S., Pacciani, L., Rapisarda, M., Soffitta, P., Trifoglio, M., Argan, A., Boffelli, F., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Chen, A., Cocco, V., D'Ammando, F., Paris, G. D., Cocco, G. D., Persio, G. D., Ferrari, A., Fiorini, M., Froysland, T., Gianotti, F., Morselli, A., Pellizzoni, A., Perotti, F., Picozza, P., Piano, G., Pilia, M., Prest, M., Pucella, G., Rappoldi, A., Rubini, A., Sabatini, S., Striani, E., Trois, A., Vallazza, E., Vittorini, V., Zambra, A., Zanello, D., Antonelli, L. A., Colafrancesco, S., Gasparrini, D., Giommi, P., Pittori, C., Preger, B., Santolamazza, P., Verrecchia, F., Salotti, L., Marisaldi M, Fuschino F, Labanti C, Galli M, Longo F, Del Monte E, Barbiellini G, Tavani M, Giuliani A, Moretti E, Vercellone S, Costa E, Cutini S, Donnarumma I, Evangelista Y, Feroci M, Lapshov I, Lazzarotto F, Lipari P, Mereghetti S, Pacciani L, Rapisarda M, Soffitta P, Trifoglio M, Argan A, Boffelli F, Bulgarelli A, Caraveo P, Cattaneo PW, Chen A, Cocco V, DAmmando F, De Paris G, Di Cocco G, Di Persio G, Ferrari A, Fiorini M, Froysland T, Gianotti F, Morselli A, Pellizzoni A, Perotti F, Picozza P, Piano G, Pilia M, Prest M, Pucella G, Rappoldi A, Rubini A, Sabatini S, Striani E, Trois A, Vallazza E, Vittorini V, Zambra A, Zanello D, Antonelli LA, Colafrancesco S, Gasparrini D, Giommi P, Pittori C, Preger B, Santolamazza P, Verrecchia F, Salotti L, M., Marisaldi, F., Fuschino, C., Labanti, M., Galli, Longo, Francesco, E. D., Monte, G., Barbiellini, M., Tavani, A., Giuliani, E., Moretti, S., Vercellone, E., Costa, S., Cutini, I., Donnarumma, Y., Evangelista, M., Feroci, I., Lapshov, F., Lazzarotto, P., Lipari, S., Mereghetti, L., Pacciani, M., Rapisarda, P., Soffitta, M., Trifoglio, A., Argan, F., Boffelli, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, A., Chen, V., Cocco, F., D'Ammando, G. D., Pari, G. D., Cocco, G. D., Persio, A., Ferrari, M., Fiorini, T., Froysland, F., Gianotti, A., Morselli, A., Pellizzoni, F., Perotti, P., Picozza, G., Piano, M., Pilia, M., Prest, G., Pucella, A., Rappoldi, A., Rubini, S., Sabatini, E., Striani, A., Troi, E., Vallazza, V., Vittorini, A., Zambra, D., Zanello, L. A., Antonelli, S., Colafrancesco, D., Gasparrini, P., Giommi, C., Pittori, B., Preger, P., Santolamazza, F., Verrecchia, and L., Salotti
Subjects: Agile, terrestrial gamma ray flashes, minicalorimeter, High Energy Gamma-ray Astronomy, AGILE satellite, Terrestrial Gamma-ray Flashes, terrestrial gamma ray flashes, AGILE satellite
Abstract: We report the detection by the Astrorivelatore Gamma a Immagini Leggero (AGILE) satellite of terrestrial gamma ray flashes (TGFs) obtained with the minicalorimeter (MCAL) detector operating in the energy range 0.3-100 MeV. We select events typically lasting a few milliseconds with spectral and directional selections consistent with the TGF characteristics previously reported by other space missions. During the period 1 June 2008 to 31 March 2009 we detect 34 high-confidence events showing millisecond durations and a geographical distribution peaked over continental Africa and Southeast Asia. For the first time, AGILE-MCAL detects photons associated with TGF events up to 40 MeV. We determine the cumulative spectral properties of the spectrum in the range 0.5-40 MeV, which can be effectively described by a Bremsstrahlung spectrum. We find that both the TGF cumulative spectral properties and their geographical distribution are in good agreement with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) results.
Published: 2010

38. 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

39. 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

40. 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

41. AGILE detection of intense gamma-ray activity from the blazar PKS 0537-441 in October 2008

Author: Marco Feroci, Luigi Pacciani, F. Boffelli, G. De Paris, E. Vallazza, Martino Marisaldi, Claudio Labanti, C. Pittori, T. Froysland, Domenico Impiombato, Ennio Morelli, A. Zambra, A. Morselli, F. Longo, A. Treves, Fulvio Gianotti, A. W. Chen, P. Caraveo, M. Fiorini, L. Salotti, G. Di Cocco, Francesco Lazzarotto, F. Perotti, E. Del Monte, G. Pucella, M. Perri, Filippo D'Ammando, G. Barbiellini, V. Vittorini, M. Prest, P. Santolamazza, M. Galli, G. Piano, F. Verrecchia, Marco Tavani, P. Giommi, P. W. Cattaneo, A. Argan, I. Donnarumma, Y. Evangelista, Andrea Bulgarelli, A. Pellizzoni, Sandro Mereghetti, Enrico Costa, Maura Pilia, Elena Pian, E. Striani, Alessio Trois, P. Picozza, I. Lapshov, S. Colafrancesco, M. Trifoglio, S. Sabatini, A. Giuliani, D. Zanello, Hans A. Krimm, Massimo Rapisarda, L. A. Antonelli, V. Cocco, A. Rappoldi, Paolo Lipari, F. Fuschino, D. Fugazza, Paolo Soffitta, P. Romano, S. Vercellone, Pucella G, DAmmando F, Romano P, Treves A, Pian E, Vercellone S, Vittorini V, Piano G, Impiombato D, Fugazza D, Verrecchia F, Krimm HA, Donnarumma I, Tavani M, Bulgarelli A, Chen AW, Giuliani A, Longo F, Pacciani L, Argan A, Barbiellini G, Boffelli F, 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, Fuschino F, Galli M, Gianotti F, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Marisaldi M, Mereghetti S, Morelli E, Morselli A, Pellizzoni A, Perotti F, 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, Perri M, Pittori C, Santolamazza P, Giommi P, Antonelli LA, Colafrancesco S, Salotti L, G., Pucella, F., D'Ammando, P., Romano, A., Treve, E., Pian, S., Vercellone, V., Vittorini, G., Piano, D., Impiombato, D., Fugazza, F., Verrecchia, H. A., Krimm, I., Donnarumma, 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, E., Costa, E. D., Monte, G. D., Pari, G. D., Cocco, Y., Evangelista, M., Feroci, M., Fiorini, T., Froysland, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, M., Marisaldi, S., Mereghetti, E., Morelli, A., Morselli, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, S., Sabatini, P., Soffitta, E., Striani, M., Trifoglio, A., Troi, E., Vallazza, A., Zambra, D., Zanello, M., Perri, C., Pittori, P., Santolamazza, P., Giommi, L. A., Antonelli, S., Colafrancesco, and L., Salotti
Subjects: Swift Gamma-Ray Burst Mission, gamma-ray activity, Astrophysics::High Energy Astrophysical Phenomena, Flux, Context (language use), Astrophysics, High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, law.invention, Luminosity, Telescope, AGILE, X-ray, law, Target of opportunity, gamma rays: general – BL Lacertae objects: individual: PKS 0537-441 – radiation mechanisms: non-thermal, Blazar, Physics, Astronomy, Astronomy and Astrophysics, Gamma-Ray Imaging Detector, Space and Planetary Science, Spectral energy distribution
Abstract: Context. We report the detection by the AGILE satellite of intense gamma-ray activity from the source 1AGL J0538-4424, associated with the low-energy-peaked BL Lac PKS 0537-441, during a target of opportunity (ToO) observation performed on 2008 October 10-17, triggered by a Fermi-LAT alert, together with REM and Swift observations. Aims. The quasi-simultaneous near-infrared, optical, UV, X-ray, and gamma-ray coverage allowed us to investigate the behaviour of the source in different energy bands and study the spectral energy distribution and a theoretical model that can describe the gamma-ray state observed in mid-October. Methods. AGILE observed the source with its two co-aligned imagers: the Gamma-Ray Imaging Detector (GRID) and the hard X-ray imager (SuperAGILE), sensitive in the 30 MeV-30 GeV and 18-60 keV ranges, respectively. During the AGILE observation, the source was monitored simultaneously in the UV and X-ray bands by the Swift satellite through 6 ToO observations carried out between 2008 October 8 and 17. Moreover, the source was observed in the near-infrared and optical bands by the REM telescope on 2008 October 7, 8, and 9. Results. During 2008 October 10-17, AGILE-GRID detected gamma-ray emission from PKS 0537-441 at a significance level of 5.3-sigma with an average flux of (42 +/- 11) x 10(-8) photons cm(-2) s(-1) for energies higher than 100 MeV. A significant increase in the gamma-ray activity was detected between the first and the second halves of the observing period. REM and Swift/XRT detected the source in near-infrared/optical and X-rays during a relatively low and intermediate activity state, respectively, with no signs of evident variability in the different observations. However, Swift/UVOT detected an increase between the first and the second parts of the observing period, smaller than in the gamma-rays. Conclusions. The average gamma-ray flux of PKS 0537-441 detected by AGILE is close to the average flux observed for this source by the EGRET and Fermi-LAT instruments, with an increase of a factor 3 throughout the observation period up to a flux level slightly lower than the highest flux observed by Fermi-LAT during the first 11 months of operation. The spectral energy distribution of PKS 0537-441 in mid-October 2008 seems to require two synchrotron self-Compton components to be modelled, to account for both the near-infrared/optical bump and the X-ray data, together with the information on the gamma-ray flux level observed by AGILE. An alternative model based on the external Compton radiation, which requires an accretion disk with a relatively high luminosity, is also proposed.
Published: 2010

42. The Extraordinary Gamma-Ray Flare Of The Blazar 3c 454.3

Author: E. Striani, S. Vercellone, M. Tavani, V. Vittorini, F. D’Ammando, I. Donnarumma, L. Pacciani, G. Pucella, A. Bulgarelli, M. Trifoglio, F. Gianotti, P. Giommi, A. Argan, G. Barbiellini, P. Caraveo, P. W. Cattaneo, A. W. Chen, E. Costa, G. De Paris, E. Del Monte, G. Di Cocco, Y. Evangelista, M. Feroci, A. Ferrari, M. Fiorini, F. Fuschino, M. Galli, A. Giuliani, M. Giusti, C. Labanti, F. Lazzarotto, P. Lipari, F. Longo, M. Marisaldi, S. Mereghetti, E. Morelli, E. Moretti, A. Morselli, A. Pellizzoni, F. Perotti, G. Piano, P. Picozza, M. Pilia, M. Prest, M. Rapisarda, A. Rappoldi, S. Sabatini, E. Scalise, P. Soffitta, A. Trois, E. Vallazza, A. Zambra, D. Zanello, C. Pittori, F. Verrecchia, P. Santolamazza, F. Lucarelli, S. Colafrancesco, L. A. Antonelli, L. Salotti, E., Striani, S., Vercellone, M., Tavani, V., Vittorini, F., D'Ammando, I., Donnarumma, L., Pacciani, G., Pucella, A., Bulgarelli, M., Trifoglio, F., Gianotti, P., Giommi, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, A. W., Chen, E., Costa, G. D., Pari, E. D., Monte, G. D., Cocco, Y., Evangelista, M., Feroci, 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, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, S., Sabatini, E., Scalise, P., Soffitta, A., Troi, E., Vallazza, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, P., Santolamazza, F., Lucarelli, S., Colafrancesco, L. A., Antonelli, L., Salotti, Striani E, Vercellone S, Tavani M, Vittorini V, DAmmando F, Donnarumma I, Pacciani L, Pucella G, Bulgarelli A, Trifoglio M, Gianotti F, Giommi P, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Chen AW, Costa E, De Paris G, Del Monte E, Di Cocco G, Evangelista Y, Feroci M, 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, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Prest M, Rapisarda M, Rappoldi A, Sabatini S, Scalise E, Soffitta P, Trois A, Vallazza E, Zambra A, Zanello D, Pittori C, Verrecchia F, Santolamazza P, Lucarelli F, Colafrancesco S, Antonelli LA, and Salotti L
Subjects: Agile, Cosmology and Nongalactic Astrophysics (astro-ph.CO), blazar, gamma detection, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astrophysics, Type (model theory), Vela, High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, law.invention, Pulsar, law, Blazar, Physics, gamma rays: galaxies – quasars: individual (3C 454.3), Gamma ray, Astronomy and Astrophysics, Quasar, Space and Planetary Science, Astrophysics - Cosmology and Nongalactic Astrophysics, Flare
Abstract: We present the gamma-ray data of the extraordinary flaring activity above 100 MeV from the flat spectrum radio quasar 3C 454.3 detected by AGILE during the month of December 2009. 3C 454.3, that has been among the most active blazars of the FSRQ type since 2007, was detected in the gamma-ray range with a progressively rising flux since November 10, 2009. The gamma-ray flux reached a value comparable with that of the Vela pulsar on December 2, 2009. Remarkably, between December 2 and 3, 2009 the source more than doubled its gamma-ray emission and became the brightest gamma-ray source in the sky with a peak flux of F_{\gamma,p} = (2000 \pm 400) x 10^-8 ph cm^-2 s^-1 for a 1-day integration above 100 MeV. The gamma-ray intensity decreased in the following days with the source flux remaining at large values near F \simeq (1000 \pm 200) x 10^-8 ph cm^-2 s^-1 for more than a week. This exceptional gamma-ray flare dissipated among the largest ever detected intrinsic radiated power in gamma-rays above 100 MeV (L_{\gamma, source, peak} \simeq 3 x 10^46 erg s^-1, for a relativistic Doppler factor of {\delta} \simeq 30). The total isotropic irradiated energy of the month-long episode in the range 100 MeV - 3 GeV is E_{\gamma,iso} \simeq 10^56 erg. We report the intensity and spectral evolution of the gamma-ray emission across the flaring episode. We briefly discuss the important theoretical implications of our detection., Comment: 17 pages, 3 figures, ApJ accepted
Published: 2010

43. 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

44. 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

45. Extreme particle acceleration in the microquasar Cygnus X-3

Author: Francesco Longo, Martino Marisaldi, C. Pittori, Paolo Lipari, Arnaud Ferrari, M. Prest, Sandro Mereghetti, P. W. Cattaneo, S. Sabatini, A. Pellizzoni, E. Striani, I. Lapshov, F. Perotti, S. Colafrancesco, Fulvio Gianotti, Francesco Lazzarotto, A. Giuliani, E. Rossi, Ennio Morelli, Karri I. I. Koljonen, Marco Tavani, E. Scalise, Y. Evangelista, Maura Pilia, Guy G. Pooley, M. Galli, F. Fuschino, Alessio Trois, I. Donnarumma, Massimo Rapisarda, F. Verrecchia, N. A. Nizhelskij, P. A. Caraveo, E. Del Monte, D. Zanello, L. Salotti, V. Cocco, M. Trifoglio, G. Pucella, A. Mauri, A. Rappoldi, E. Vallazza, G. De Paris, T. Contessi, G. Piano, A. W. Chen, P. Giommi, A. Argan, Andrea Bulgarelli, Enrico Costa, G. Di Persio, A. Morselli, Filippo D'Ammando, Paolo Soffitta, S. Vercellone, Michael L. McCollough, P. Picozza, P. Santolamazza, Alda Rubini, Sergei A. Trushkin, A. Zambra, M. Mastropietro, Guido Barbiellini, V. Vittorini, Marco Feroci, Luigi Pacciani, Angelo Antonelli, E. Mattaini, G. Di Cocco, Claudio Labanti, M., Tavani, A., Bulgarelli, G., Piano, S., Sabatini, E., Striani, Y., Evangelista, A., Troi, G., Pooley, S., Trushkin, N. A., Nizhelskij, M., Mccollough, K. I. I., Koljonen, G., Pucella, A., Giuliani, A. W., Chen, E., Costa, V., Vittorini, M., Trifoglio, F., Gianotti, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, V., Cocco, T., Contessi, F., D'Ammando, E. D., Monte, G. D., Pari, G. D., Cocco, G. D., Persio, I., Donnarumma, M., Feroci, A., Ferrari, F., Fuschino, M., Galli, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, Longo, Francesco, E., Mattaini, M., Marisaldi, M., Mastropietro, A., Mauri, S., Mereghetti, E., Morelli, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, E., Rossi, A., Rubini, E., Scalise, P., Soffitta, E., Vallazza, S., Vercellone, A., Zambra, D., Zanello, C., Pittori, F., Verrecchia, P., Giommi, S., Colafrancesco, P., Santolamazza, A., Antonelli, L., Salotti, Tavani M, Bulgarelli A, Piano G, Sabatini S, Striani E, Evangelista Y, Trois A, Pooley G, Trushkin S, Nizhelskij NA, McCollough M, Koljonen KII, Pucella G, Giuliani A, Chen AW, Costa E, Vittorini V, Trifoglio M, Gianotti F, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Cocco V, Contessi T, DAmmando F, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Feroci M, Ferrari A, Fuschino F, Galli M, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Longo F, Mattaini E, Marisaldi M, Mastropietro M, Mauri A, Mereghetti S, Morelli E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Picozza P, Pilia M, Prest M, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Scalise E, Soffitta P, Vallazza E, Vercellone S, Zambra A, Zanello D, Pittori C, Verrecchia F, Giommi P, Colafrancesco S, Santolamazza P, Antonelli A, and Salotti L
Subjects: Active galactic nucleus, Black Holes, Astrophysics::High Energy Astrophysical Phenomena, super massive black holes, X-ray binary, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, High Energy Gamma-ray Astronomy, Relativistic particle, AGILE, Astrophysical jet, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Supermassive black hole, Cygnus, Multidisciplinary, particle acceleration, microquasar, Cygnus X-3, Astronomy, X-ray emission, Particle acceleration, Black hole, Neutron star, AGILE satellite
Abstract: Galactic microquasars are binaries with a neutron star or stellar-mass black hole accreting gas from a companion star. They can accelerate particles to relativistic energies and emit radio flares, but the mechanism of jet energization is not known. A survey of the Cygnus region between mid-2007 and mid-2009 has detected four major γ-ray flaring episodes with energies over 100 MeV, each lasting 1 or 2 days, emanating from the microquasar Cygnus X-3. There is a clear pattern of temporal correlation between the γ-ray flares and transitional spectral states of radio and X-ray emission. Particle acceleration occurred a few days before radio jet ejections for two of the flares, suggesting that jet formation involves the production of highly energetic particles. Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated γ-ray emission. Galactic 'microquasars' also produce relativistic jets; however, apart from an isolated event detected in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar. Here, a report of four γ-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 illuminates this important problem. Super-massive black holes in active galaxies can accelerate particles to relativistic energies1, producing jets with associated γ-ray emission. Galactic ‘microquasars’, which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares2. Apart from an isolated event detected3 in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four γ-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary4,5,6 that sporadically produces radio jets7,8,9). There is a clear pattern of temporal correlations between the γ-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states.
Published: 2009

46. THE JUNE 2008 FLARE OF MARKARIAN 421 FROM OPTICAL TO TeV ENERGIES

Author: I. Donnarumma, V. Vittorini, S. Vercellone, E. Del Monte, M. Feroci, F. D'Ammando, L. Pacciani, A. W. Chen, M. Tavani, A. Bulgarelli, A. Giuliani, F. Longo, G. Pucella, A. Argan, G. Barbiellini, F. Boffelli, P. Caraveo, P. W. Cattaneo, V. Cocco, E. Costa, G. De Paris, G. Di Cocco, Y. Evangelista, 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, P. Picozza, G. Porrovecchio, M. Prest, M. Rapisarda, A. Rappoldi, A. Rubini, P. Soffitta, M. Trifoglio, A. Trois, E. Vallazza, A. Zambra, D. Zanello, C. Pittori, P. Santolamazza, F. Verrecchia, P. Giommi, S. Colafrancesco, L. Salotti, M. Villata, C. M. Raiteri, W. P. Chen, N. V. Efimova, B. Jordan, T. S. Konstantinova, E. Koptelova, O. M. Kurtanidze, V. M. Larionov, J. A. Ros, A. C. Sadun, H. Anderhub, L. A. Antonelli, P. Antoranz, M. Backes, C. Baixeras, S. Balestra, J. A. Barrio, H. Bartko, D. Bastieri, J. Becerra González, J. K. Becker, W. Bednarek, K. Berger, E. Bernardini, A. Biland, R. K. Bock, G. Bonnoli, P. Bordas, D. Borla Tridon, V. Bosch-Ramon, T. Bretz, I. Britvitch, M. Camara, E. Carmona, A. Chilingarian, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, S. Covino, V. Curtef, F. Dazzi, A. De Angelis, E. De Cea del Pozo, R. de los Reyes, B. De Lotto, M. De Maria, F. De Sabata, C. Delgado Mendez, A. Dominguez, D. Dorner, M. Doro, D. Elsaesser, M. Errando, D. Ferenc, E. Fernández, R. Firpo, M. V. Fonseca, L. Font, N. Galante, R. J. García López, M. Garczarczyk, M. Gaug, F. Goebel, D. Hadasch, M. Hayashida, A. Herrero, D. Höhne-Mönch, J. Hose, C. C. Hsu, S. Huber, T. Jogler, D. Kranich, A. La Barbera, A. Laille, E. Leonardo, E. Lindfors, S. Lombardi, M. López, E. Lorenz, P. Majumdar, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, M. Mariotti, M. Martínez, D. Mazin, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, J. Moldón, M. Moles, A. Moralejo, D. Nieto, K. Nilsson, J. Ninkovic, I. Oya, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. G. Pegna, M. A. Perez-Torres, M. Persic, L. Peruzzo, F. Prada, E. Prandini, N. Puchades, A. Raymers, W. Rhode, M. Ribó, J. Rico, M. Rissi, A. Robert, S. Rügamer, A. Saggion, T. Y. Saito, M. Salvati, M. Sanchez-Conde, P. Sartori, K. Satalecka, V. Scalzotto, V. Scapin, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sierpowska-Bartosik, A. Sillanpää, J. Sitarek, D. Sobczynska, F. Spanier, A. Stamerra, L. S. Stark, L. Takalo, F. Tavecchio, P. Temnikov, D. Tescaro, M. Teshima, M. Tluczykont, D. F. Torres, N. Turini, H. Vankov, A. Venturini, V. Vitale, R. M. Wagner, W. Wittek, V. Zabalza, F. Zandanel, R. Zanin, J. Zapatero, V. Acciari, E. Aliu, T. Arlen, M. Beilicke, W. Benbow, S. M. Bradbury, J. H. Buckley, V. Bugaev, Y. Butt, K. Byrum, A. Cannon, A. Cesarini, Y. C. Chow, L. Ciupik, P. Cogan, P. Colin, W. Cui, M. K. Daniel, R. Dickherber, C. Duke, T. Ergin, S. J. Fegan, J. P. Finley, G. Finnegan, P. Fortin, A. Furniss, D. Gall, G. H. Gillanders, R. Guenette, G. Gyuk, J. Grube, D. Hanna, J. Holder, D. Horan, C. M. Hui, T. Brian Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, J. Kildea, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, S. LeBohec, G. Maier, A. McCann, M. McCutcheon, A. Milovanovic, P. Moriarty, T. Nagai, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, A. Pichel, M. Pohl, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, M. Schroedter, G. H. Sembroski, A. W. Smith, D. Steele, S. P. Swordy, M. Theiling, J. A. Toner, L. Valcarcel, A. Varlotta, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, D. A. Williams, S. Wissel, M. Wood, B. Zitzer, I., Donnarumma, V., Vittorini, S., Vercellone, E. D., Monte, M., Feroci, F., D'Ammando, L., Pacciani, A. W., Chen, M., Tavani, A., Bulgarelli, A., Giuliani, Longo, Francesco, G., Pucella, A., Argan, G., Barbiellini, F., Boffelli, P., Caraveo, P. W., Cattaneo, V., Cocco, E., Costa, G. D., Pari, G. D., Cocco, Y., Evangelista, 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, P., Picozza, G., Porrovecchio, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, 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, W. P., Chen, N. V., Efimova, B., Jordan, T. S., Konstantinova, E., Koptelova, O. M., Kurtanidze, V. M., Larionov, J. A., Ro, A. C., Sadun, H., Anderhub, L. A., Antonelli, P., Antoranz, M., Backe, C., Baixera, S., Balestra, J. A., Barrio, H., Bartko, D., Bastieri, J. B., Gonzalez, J. K., Becker, W., Bednarek, K., Berger, E., Bernardini, A., Biland, R. K., Bock, G., Bonnoli, P., Borda, D. B., Tridon, V., Bosch Ramon, T., Bretz, I., Britvitch, M., Camara, E., Carmona, A., Chilingarian, S., Commichau, J. L., Contrera, J., Cortina, M. T., Costado, S., Covino, V., Curtef, F., Dazzi, A. D., Angeli, E. D., Del Pozo, R. D., Reye, B. D., Lotto, M. D., Maria, F. D., Sabata, C. D., Mendez, A., Dominguez, D., Dorner, M., Doro, D., Elsaesser, M., Errando, D., Ferenc, E., Fernandez, R., Firpo, M. V., Fonseca, L., Font, N., Galante, R. J. G., Lopez, M., Garczarczyk, M., Gaug, F., Goebel, D., Hadasch, M., Hayashida, A., Herrero, D., Hohne Monch, J., Hose, C. C., Hsu, S., Huber, T., Jogler, D., Kranich, A. L., Barbera, A., Laille, E., Leonardo, E., Lindfor, S., Lombardi, M., Lopez, E., Lorenz, P., Majumdar, G., Maneva, N., Mankuzhiyil, K., Mannheim, L., Maraschi, M., Mariotti, M., Martinez, D., Mazin, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, J., Moldon, M., Mole, A., Moralejo, D., Nieto, K., Nilsson, J., Ninkovic, I., Oya, R., Paoletti, J. M., Parede, M., Pasanen, D., Pascoli, F., Pau, R. G., Pegna, M. A., Perez Torre, M., Persic, L., Peruzzo, F., Prada, E., Prandini, N., Puchade, A., Raymer, W., Rhode, M., Ribo, J., Rico, M., Rissi, A., Robert, S., Rugamer, A., Saggion, T. Y., Saito, M., Salvati, M., Sanchez Conde, P., Sartori, K., Satalecka, V., Scalzotto, V., Scapin, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sierpowska Bartosik, A., Sillanpaa, J., Sitarek, D., Sobczynska, F., Spanier, A., Stamerra, L. S., Stark, L., Takalo, F., Tavecchio, P., Temnikov, D., Tescaro, M., Teshima, M., Tluczykont, D. F., Torre, N., Turini, H., Vankov, A., Venturini, V., Vitale, R. M., Wagner, W., Wittek, V., Zabalza, F., Zandanel, R., Zanin, J., Zapatero, V., Acciari, E., Aliu, T., Arlen, M., Beilicke, W., Benbow, S. M., Bradbury, J. H., Buckley, V., Bugaev, Y., Butt, K., Byrum, A., Cannon, A., Cesarini, Y. C., Chow, L., Ciupik, P., Cogan, P., Colin, W., Cui, M. K., Daniel, R., Dickherber, C., Duke, T., Ergin, S. J., Fegan, J. P., Finley, G., Finnegan, P., Fortin, A., Furni, D., Gall, G. H., Gillander, R., Guenette, G., Gyuk, J., Grube, D., Hanna, J., Holder, D., Horan, C. M., Hui, T. B., Humensky, A., Imran, P., Kaaret, N., Karlsson, M., Kertzman, D., Kieda, J., Kildea, A., Konopelko, H., Krawczynski, F., Krennrich, M. J., Lang, S., Lebohec, G., Maier, A., Mccann, M., Mccutcheon, A., Milovanovic, P., Moriarty, T., Nagai, R. A., Ong, A. N., Otte, D., Pandel, J. S., Perkin, A., Pichel, M., Pohl, K., Ragan, L. C., Reye, P. T., Reynold, E., Roache, H. J., Rose, M., Schroedter, G. H., Sembroski, A. W., Smith, D., Steele, S. P., Swordy, M., Theiling, J. A., Toner, L., Valcarcel, A., Varlotta, S. P., Wakely, J. E., Ward, T. C., Weeke, A., Weinstein, D. A., William, S., Wissel, M., Wood, B., Zitzer, Donnarumma I, Vittorini V, Vercellone S, del Monte E, Feroci M, DAmmando F, Pacciani L, Chen A W, Tavani M, Bulgarelli A, Giuliani A, Longo F, Pucella G, Argan A, Barbiellini G, Boffelli F, Caraveo P, Cattaneo P W, Cocco V, Costa E, DeParis G, Di Cocco G, Evangelista Y, 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, Picozza P, Porrovecchio G, Prest M, Rapisarda M, Rappoldi A, Rubini A, 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 C M, Chen W P, Efimova N V, Jordan B, Konstantinova T S, Koptelova E, Kurtanidze O M, Larionov V M, Ros J A, Sadun A C, Anderhub H, Antonelli L A, Antoranz P, Backes M, Baixeras C, Balestra S, Barrio J A, Bartko H, Bastieri D, González J Becerra, Becker J K, Bednarek W, Berger K, Bernardini E, Biland A, Bock R K, Bonnoli G, Bordas P, Tridon D Borla, Bosch-Ramon V, Bretz T, Britvitch I, Camara M, Carmona E, Chilingarian A, Commichau S, Contreras J L, Cortina J, Costado M T, Covino S, Curtef V, Dazzi F, DeAngelis A, DeCea del Pozo E, de los Reyes R, DeLotto B, DeMaria M, DeSabata F, Mendez C Delgado, Dominguez A, Dorner D, Doro M, Elsaesser D, Errando M, Ferenc D, Fernández E, Firpo R, Fonseca M V, Font L, Galante N, García López R J, Garczarczyk M, Gaug M, Goebel F, Hadasch D, Hayashida M, Herrero A, Höhne-Mönch D, Hose J, Hsu C C, Huber S, Jogler T, Kranich D, La Barbera A, Laille A, Leonardo E, Lindfors E, Lombardi S, López M, Lorenz E, Majumdar P, Maneva G, Mankuzhiyil N, Mannheim K, Maraschi L, Mariotti M, Martínez M, Mazin D, Meucci M, Meyer M, Miranda J M, Mirzoyan R, Moldón J, Moles M, Moralejo A, Nieto D, Nilsson K, Ninkovic J, Oya I, Paoletti R, Paredes J M, Pasanen M, Pascoli D, Pauss F, Pegna R G, Perez-Torres M A, Persic M, Peruzzo L, Prada F, Prandini E, Puchades N, Raymers A, Rhode W, Ribó M, Rico J, Rissi M, Robert A, Rügamer S, Saggion A, Saito T Y, Salvati M, Sanchez-Conde M, Sartori P, Satalecka K, Scalzotto V, Scapin V, Schweizer T, Shayduk M, Shinozaki K, Shore S N, Sidro N, Sierpowska-Bartosik A, Sillanpää A, Sitarek J, Sobczynska D, Spanier F, Stamerra A, Stark L S, Takalo L, Tavecchio F, Temnikov P, Tescaro D, Teshima M, Tluczykont M, Torres D F, Turini N, Vankov H, Venturini A, Vitale V, Wagner R M, Wittek W, Zabalza V, Zandanel F, Zanin R, Zapatero J, Acciari V, Aliu E, Arlen T, Beilicke M, Benbow W, Bradbury S M, Buckley J H, Bugaev V, Butt Y, Byrum K, Cannon A, Cesarini A, Chow Y C, Ciupik L, Cogan P, Colin P, Cui W, Daniel M K, Dickherber R, Duke C, Ergin T, Fegan S J, Finley J P, Finnegan G, Fortin P, Furniss A, Gall D, Gillanders G H, Guenette R, Gyuk G, Grube J, Hanna D, Holder J, Horan D, Hui C M, Humensky T Brian, Imran A, Kaaret P, Karlsson N, Kertzman M, Kieda D, Kildea J, Konopelko A, Krawczynski H, Krennrich F, Lang M J, LeBohec S, Maier G, McCann A, McCutcheon M, Milovanovic A, Moriarty P, Nagai T, Ong R A, Otte A N, Pandel D, Perkins J S, Pichel A, Pohl M, Ragan K, Reyes L C, Reynolds P T, Roache E, Rose H J, Schroedter M, Sembroski G H, Smith A W, Steele D, Swordy S P, Theiling M, Toner J A, Valcarcel L, Varlotta A, Wakely S P, Ward J E, Weekes T C, Weinstein A, Williams D A, Wissel S, Wood M, and Zitzer B
Subjects: campaign, Raigs còsmics, BL Lacertae: individual: Mrk421, galaxies: jets, X-Rays: Galaxies, gamma rays: observations, radiation mechanisms: nonthermal, bl-lacertae objects, blazars, Flux, Astrophysics, 01 natural sciences, 7. Clean energy, High Energy Gamma-ray Astronomy, law.invention, Raigs gamma, law, optical, MAGIC (telescope), Agile, blazr, X-ray, gamma, high energy observation, 010303 astronomy & astrophysics, webt, Physics, x-ray-spectra, Astrophysics (astro-ph), gamma-rays, lac objects, xmm-newton, Spectral energy distribution, Electrónica, Física nuclear, Raigs X, Electricidad, Flare, outburst, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, 0103 physical sciences, X-rays, BL Lacertae objects: individual (Mrk 421) – gamma rays: observations – galaxies: jets – radiation mechanisms: non-thermal – X-rays: galaxies, Blazar, Cosmic rays, 010308 nuclear & particles physics, Gamma rays, Astronomy and Astrophysics, Active Galactic Nuclei, radiation mechanisms: non-thermal, Light curve, Galaxies, Galàxies, MAGIC telescope, Space and Planetary Science, Very High Energy Gamma-ray Astronomy, ddc:520, AGILE satellite, bl lacertae objects: individual (mrk 421), Energy (signal processing), Lepton
Abstract: We present optical, X-ray, high energy ($\lessapprox 30$ GeV) and very high energy ($\gtrapprox 100$ GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high energy $\gamma$-ray signal was detected by AGILE with \sqrt{TS}=4.5 on June 9--15, with $F(E>100 \mathrm{MeV})= 42^{+14}_{-12}\times 10^{-8}$ photons cm$^{-2}$ s$^{-1}$. This flaring state is brighter than the average flux observed by EGRET by a factor of $\sim$3, but still consistent with the highest EGRET flux. In hard X-rays (20-60 keV) SuperAGILE resolved a 5-day flare (June 9-15) peaking at $\sim$ 55 mCrab. SuperAGILE, RXTE/ASM and Swift/BAT data show a correlated flaring structure between soft and hard X-rays. Hints of the same flaring behavior are also detected in the simultaneous optical data provided by the GASP-WEBT. A Swift/XRT observation near the flaring maximum revealed the highest 2-10 keV flux ever observed from this source, of 2.6 $\times 10^{-9}$ erg cm$^{-2}$ s$^{-1}$ (i.e. > 100 mCrab). A peak synchrotron energy of $\sim$3 keV was derived, higher than typical values of $\sim$0.5-1 keV. VHE observations with MAGIC and VERITAS on June 6-8 show the flux peaking in a bright state, well correlated with the X-rays. This extraordinary set of simultaneous data, covering a twelve-decade spectral range, allowed for a deep analysis of the spectral energy distribution as well as of correlated light curves. The $\gamma$-ray flare can be interpreted within the framework of the synchrotron self-Compton model in terms of a rapid acceleration of leptons in the jet., Comment: accepted for publication in ApJL, 7 pages, 2 figures, 1 table
Published: 2009
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47. POWERFUL HIGH-ENERGY EMISSION OF THE REMARKABLE BL LAC OBJECT S5 0716+714

Author: A. W. Chen, Marco Tavani, Alessandro Paggi, G. Pucella, Francesco Longo, Sergio Colafrancesco, A. Cavaliere, Luigi Pacciani, Andrea Bulgarelli, S. Vercellone, I. Donnarumma, Paolo Giommi, Filippo D'Ammando, A. Giuliani, V. Vittorini, Attilio Ferrari, Vittorini V, Tavani M, Paggi A, Cavaliere A, Bulgarelli A, Chen AW, DAmmando F, Donnarumma I, Giuliani A, Longo F, Pacciani L, Pucella G, Vercellone S, Ferrari A, Colafrancesco S, Giommi P, V., Vittorini, M., Tavani, A., Paggi, A., Cavaliere, A., Bulgarelli, A. W., Chen, F., D'Ammando, I., Donnarumma, A., Giuliani, Longo, Francesco, L., Pacciani, G., Pucella, S., Vercellone, A., Ferrari, S., Colafrancesco, and P., Giommi
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Range (particle radiation), High energy, Supermassive black hole, Accretion (meteorology), Astrophysics::High Energy Astrophysical Phenomena, BL Lacertae objects: individual (S5 0716+714), FOS: Physical sciences, Active Galactic Nuclei, Astronomy and Astrophysics, Astrophysics, High Energy Gamma-ray Astronomy, AGILE satellite, Black hole, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, gamma rays: observations, BL Lac object
Abstract: BL Lac objects of the intermediate subclass (IBLs) are known to emit a substantial fraction of their power in the energy range 0.1--10 GeV. Detecting gamma-ray emission from such sources provides therefore a direct probe of the emission mechanisms and of the underlying powerhouse. The AGILE gamma-ray satellite detected the remarkable IBL S5 0716+714 (z \simeq 0.3) during a high state in the period from 2007 September - October, marked by two very intense flares reaching peak fluxes of 200\times10^{-8} ph / cm^2 s above 100 MeV, with simultaneous optical and X-ray observations. We present here a theoretical model for the two major flares and discuss the overall energetics of the source. We conclude that 0716+714 is among the brightest BL Lac's ever detected at gamma-ray energies. Because of its high power and lack of signs for ongoing accretion or surrounding gas, the source is an ideal candidate to test the maximal power extractable from a rotating supermassive black hole via the pure Blandford-Znajek (BZ) mechanism. We find that during the 2007 gamma-ray flares our source approached or just exceeded the upper limit set by BZ for a black hole of mass 10^9 M_sun, 12 pages, 3 figures
Published: 2009

48. The AGILE Mission

Author: Tavani M, Barbiellini G, Argan A, Boffelli F, Bulgarelli A, Caraveo P, Cattaneo PW, Chen AW, Cocco V, Costa E, Del Monte E, De Paris G, Di Cocco G, Di Persio G, Donnarumma I, Evangelista Y, Feroci M, Ferrari A, Fiorini M, Fornari F, Fuschino F, Froysland T, Frutti M, Galli M, Gianotti F, Giuliani A, Labanti C, Lapshov I, Lazzarotto F, Liello F, Lipari P, Longo F, Mattaini E, Marisaldi M, Mastropietro M, Mauri A, Mauri F, Mereghetti S, Morelli E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Piano G, Picozza P, Pontoni C, Porrovecchio G, Prest M, Pucella G, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Soffitta P, Traci A, Trifoglio M, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Preger B, Santolamazza P, Verrecchia F, Giommi P, Colafrancesco S, Antonelli A, Cutini S, Gasparrini D, Stellato S, Fanari G, Primavera R, Tamburelli F, Viola F, Guarrera G, Salotti L, D'Amico F, Marchetti E, Crisconio M, Sabatini P, Annoni G, Alia S, Longoni A, Sanquerin R, Battilana M, Concari P, Dessimone E, Grossi R, Parise A, Monzani F, Artina E, Pavesi R, Marseguerra G, Nicolini L, Scandelli L, Soli L, Vettorello V, Zardetto E, Bonati A, Maltecca L, D'Alba E, Patane M, Babini G, Onorati F, Acquaroli L, Angelucci M, Morelli B, Agostara C, Cerone M, Michetti A, Tempesta P, D'Eramo S, Rocca F, Giannini F, Borghi G, Garavelli B, Conte M, Balasini M, Ferrario I, Vanotti M, Collavo E, Giacomazzo M., D'AMMANDO, FILIPPO, M., Tavani, G., Barbiellini, A., Argan, F., Boffelli, A., Bulgarelli, P., Caraveo, P. W., Cattaneo, A. W., Chen, V., Cocco, 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., Fornari, F., Fuschino, T., Froysland, M., Frutti, M., Galli, F., Gianotti, A., Giuliani, C., Labanti, I., Lapshov, F., Lazzarotto, F., Liello, P., Lipari, Longo, Francesco, E., Mattaini, M., Marisaldi, M., Mastropietro, A., Mauri, F., Mauri, S., Mereghetti, E., Morelli, A., Morselli, L., Pacciani, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, C., Pontoni, G., Porrovecchio, M., Prest, G., Pucella, M., Rapisarda, A., Rappoldi, E., Rossi, A., Rubini, P., Soffitta, A., Traci, M., Trifoglio, A., Troi, E., Vallazza, S., Vercellone, V., Vittorini, A., Zambra, D., Zanello, C., Pittori, B., Preger, P., Santolamazza, F., Verrecchia, P., Giommi, S., Colafrancesco, A., Antonelli, S., Cutini, D., Gasparrini, S., Stellato, G., Fanari, R., Primavera, F., Tamburelli, F., Viola, G., Guarrera, L., Salotti, F., D'Amico, E., Marchetti, M., Crisconio, P., Sabatini, G., Annoni, S., Alia, A., Longoni, R., Sanquerin, M., Battilana, P., Concari, E., Dessimone, R., Grossi, A., Parise, F., Monzani, E., Artina, R., Pavesi, G., Marseguerra, L., Nicolini, L., Scandelli, L., Soli, V., Vettorello, E., Zardetto, A., Bonati, L., Maltecca, E., D'Alba, M., Patane, G., Babini, F., Onorati, L., Acquaroli, M., Angelucci, B., Morelli, C., Agostara, M., Cerone, A., Michetti, P., Tempesta, S., D'Eramo, F., Rocca, F., Giannini, G., Borghi, B., Garavelli, M., Conte, M., Balasini, I., Ferrario, M., Vanotti, E., Collavo, M., Giacomazzo, Tavani M, Barbiellini G, Argan A, Boffelli F, Bulgarelli A, Caraveo P, Cattaneo PW, Chen AW, Cocco V, 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, Fornari F, Fuschino F, Froysland T, Frutti M, Galli M, Gianotti F, Giuliani A, Labanti C, Lapshov I, Lazzarotto F, Liello F, Lipari P, Longo F, Mattaini E, Marisaldi M, Mastropietro M, Mauri A, Mauri F, Mereghetti S, Morelli E, Morselli A, Pacciani L, Pellizzoni A, Perotti F, Piano G, Picozza P, Pontoni C, Porrovecchio G, Prest M, Pucella G, Rapisarda M, Rappoldi A, Rossi E, Rubini A, Soffitta P, Traci A, Trifoglio M, Trois A, Vallazza E, Vercellone S, Vittorini V, Zambra A, Zanello D, Pittori C, Preger B, Santolamazza P, Verrecchia F, Giommi P, Colafrancesco S, Antonelli A, Cutini S, Gasparrini D, Stellato S, Fanari G, Primavera R, Tamburelli F, Viola F, Guarrera G, Salotti L, D'Amico F, Marchetti E, Crisconio M, Sabatini P, Annoni G, Alia S, Longoni A, Sanquerin R, Battilana M, Concari P, Dessimone E, Grossi R, Parise A, Monzani F, Artina E, Pavesi R, Marseguerra G, Nicolini L, Scandelli L, Soli L, Vettorello V, Zardetto E, Bonati A, Maltecca L, D'Alba E, Patane M, Babini G, Onorati F, Acquaroli L, Angelucci M, Morelli B, Agostara C, Cerone M, Michetti A, Tempesta P, D'Eramo S, Rocca F, Giannini F, Borghi G, Garavelli B, Conte M, Balasini M, Ferrario I, Vanotti M, Collavo E, and Giacomazzo M
Subjects: Agile, Active galactic nucleus, gamma and X ray detection, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, satellite, FOS: Physical sciences, Astrophysics, High Energy Gamma-ray Astronomy, Pulsar, astro-ph, Angular resolution, media_common, Physics, Calorimeter (particle physics), Astrophysics (astro-ph), Detector, AGILE satellite, Detectors, Astronomy and Astrophysics, Universe, Supernova, Space and Planetary Science, Orbit (dynamics), instrumentation: detectors – techniques: high angular resolution – techniques: image processing – gamma rays: observations – X-rays: general
Abstract: AGILE is an Italian Space Agency mission dedicated to the observation of the gamma-ray Universe. The AGILE very innovative instrumentation combines for the first time a gamma-ray imager (sensitive in the energy range 30 MeV - 50 GeV), a hard X-ray imager (sensitive in the range 18-60 keV) together with a Calorimeter (sensitive in the range 300 keV - 100 MeV) and an anticoincidence system. AGILE was successfully launched on April 23, 2007 from the Indian base of Sriharikota and was inserted in an equatorial orbit with a very low particle background. AGILE provides crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, pulsars, unidentified gamma-ray sources, Galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. An optimal angular resolution (reaching 0.1-0.2 degrees in gamma-rays, 1-2 arcminutes in hard X-rays) and very large fields of view (2.5 sr and 1 sr, respectively) are obtained by the use of Silicon detectors integrated in a very compact instrument. The paper describes the AGILE Mission and its space and ground segments., 20 pages, 26 figures. submitted to Astron. & Astrophys
Published: 2009

49. 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

50. 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

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