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Articoli di riviste sul tema "Gamma ray sources"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 18 maggio 2024

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1

ZABALZA, VÍCTOR. "GAMMA-RAY OBSERVATIONS OF GAMMA-RAY BINARIES". International Journal of Modern Physics: Conference Series 28 (gennaio 2014): 1460161. http://dx.doi.org/10.1142/s2010194514601616.

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Gamma-ray binaries are binary systems that emit most of their radiative output above 1 MeV. Following the detection of five such systems in the past decade, they have been clearly established as a population of galactic GeV and TeV sources. In this review I discuss their recent gamma-ray observational results from Cherenkov telescopes and the Fermi satellite. A common trend has emerged in the high-energy spectra of several of these sources, with the detection of two separate components at GeV and TeV energies that cannot be explained as being emitted from a single region, and here I discuss a possible scenario giving rise to two separate acceleration locations in gamma-ray binaries.

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2

Romero, Gustavo E. "Microquasars and Gamma-ray Sources". Chinese Journal of Astronomy and Astrophysics 5, S1 (31 dicembre 2005): 110–20. http://dx.doi.org/10.1088/1009-9271/5/s1/110.

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3

Aharonian, F. A. "Galactic TeV gamma-ray sources". Astroparticle Physics 11, n. 1-2 (giugno 1999): 225–34. http://dx.doi.org/10.1016/s0927-6505(99)00055-9.

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4

Kifune, T., M. Sadzinska, J. Wdowczyk, A. W. Wolfendale, A. J. Norton e R. S. Warwick. "Synchrotron X-ray haloes around gamma ray sources". Monthly Notices of the Royal Astronomical Society 228, n. 2 (1 settembre 1987): 243–50. http://dx.doi.org/10.1093/mnras/228.2.243.

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5

Boer, Michel, M. Gottardi, K. Hurley e G. Pizzichini. "X-ray observations of gamma-ray burst sources". Astrophysics and Space Science 169, n. 1-2 (luglio 1990): 153–58. http://dx.doi.org/10.1007/bf00640703.

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6

PIRAN, TSVI. "GAMMA-RAY BURSTS". International Journal of Modern Physics A 17, n. 20 (10 agosto 2002): 2727–31. http://dx.doi.org/10.1142/s0217751x02011680.

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Gamma-Ray Bursts (GRBs) are the most relativistic objects discovered so far. I describe here two aspects of the relativistic nature of GRBs. Their likely association with the formation of black holes and their possible role as sources of gravitational radiation.

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7

Chen, Yang, Xiao-Jun Bi, Kun Fang, Yi-Qing Guo, Ye Liu, P. H. Thomas Tam, S. Vernetto, Zhong-Xiang Wang, Rui-Zhi Yang e Xiao Zhang. "Chapter 2 Galactic Gamma-ray Sources *". Chinese Physics C 46, n. 3 (1 marzo 2022): 030002. http://dx.doi.org/10.1088/1674-1137/ac3fa8.

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Abstract In the γ-ray sky, the highest fluxes come from Galactic sources: supernova remnants (SNRs), pulsars and pulsar wind nebulae, star forming regions, binaries and micro-quasars, giant molecular clouds, Galactic center, and the large extended area around the Galactic plane. The radiation mechanisms of γ-ray emission and the physics of the emitting particles, such as the origin, acceleration, and propagation, are of very high astrophysical significance. A variety of theoretical models have been suggested for the relevant physics, and emission with energies E≥1014 eV are expected to be crucial in testing them. In particular, this energy band is a direct window to test at which maximum energy a particle can be accelerated in the Galactic sources and whether the most probable source candidates such as Galactic center and SNRs are “PeVatrons”. Designed aiming at the very high energy (VHE, >100 GeV) observation, LHAASO will be a very powerful instrument in these astrophysical studies. Over the past decade, great advances have been made in the VHE γ-ray astronomy. More than 170 VHE γ-ray sources have been observed, and among them, 42 Galactic sources fall in the LHAASO field-of-view. With a sensitivity of 10 milli-Crab, LHAASO can not only provide accurate spectra for the known γ-ray sources, but also search for new TeV-PeV γ-ray sources. In the following sub-sections, the observation of all the Galactic sources with LHAASO will be discussed in details.

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8

Narayan, R., e T. Piran. "Do gamma-ray burst sources repeat?" Monthly Notices of the Royal Astronomical Society 265, n. 1 (1 novembre 1993): L65—L68. http://dx.doi.org/10.1093/mnras/265.1.l65.

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9

Bosch-Ramon, V., G. E. Romero, A. T. Araudo e J. M. Paredes. "Massive protostars as gamma-ray sources". Astronomy and Astrophysics 511 (febbraio 2010): A8. http://dx.doi.org/10.1051/0004-6361/200913488.

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10

Weekes, Trevor C. "Very high‐energy gamma‐ray sources". Physics Teacher 24, n. 1 (gennaio 1986): 20–28. http://dx.doi.org/10.1119/1.2341927.

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11

Meegan, Charles A., Dieter H. Hartmann, J. J. Brainerd, Michael S. Briggs, William S. Paciesas, Geoffrey Pendleton, Chryssa Kouveliotou, Gerald Fishman, George Blumenthal e Martin Brock. "Do Gamma-Ray Burst Sources Repeat?" Astrophysical Journal 446 (giugno 1995): L15. http://dx.doi.org/10.1086/187919.

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12

Kronenberg, S., G. J. Brucker, E. Bechtel e F. Gentner. "Directional Detector of Gamma Ray Sources". Health Physics 70, n. 4 (aprile 1996): 505–11. http://dx.doi.org/10.1097/00004032-199604000-00007.

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13

Nolan, P. L., W. F. Tompkins, I. A. Grenier e P. F. Michelson. "Variability of EGRET Gamma‐Ray Sources". Astrophysical Journal 597, n. 1 (novembre 2003): 615–27. http://dx.doi.org/10.1086/378353.

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14

Bhatia, V. B., S. Mishra e N. Panchapakesan. "Globular clusters as gamma ray sources". Journal of Astrophysics and Astronomy 13, n. 4 (dicembre 1992): 287–91. http://dx.doi.org/10.1007/bf02702266.

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15

Pavlenko, E., V. Malanushenko, S. Shugarov e D. Chochol. "Cataclysmic Variables and Gamma-Ray Sources". EAS Publications Series 61 (2013): 255–57. http://dx.doi.org/10.1051/eas/1361039.

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16

McLaughlin, M. A., J. R. Mattox, J. M. Cordes e D. J. Thompson. "Variability ofCGRO/EGRET Gamma‐Ray Sources". Astrophysical Journal 473, n. 2 (20 dicembre 1996): 763–72. http://dx.doi.org/10.1086/178188.

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17

Aharonian, F. A. "VHE gamma-ray sources and implications". Il Nuovo Cimento C 19, n. 6 (novembre 1996): 981–90. http://dx.doi.org/10.1007/bf02508140.

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18

Nesci, R., G. Tosti, T. Pursimo, R. Ojha e M. Kadler. "Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources". Astronomy & Astrophysics 555 (18 giugno 2013): A2. http://dx.doi.org/10.1051/0004-6361/201321094.

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19

GHISELLINI, GABRIELE. "EXTRAGALACTIC GAMMA-RAYS: GAMMA RAY BURSTS AND BLAZARS". International Journal of Modern Physics A 20, n. 29 (20 novembre 2005): 6991–7000. http://dx.doi.org/10.1142/s0217751x05030673.

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The extragalactic gamma-ray sky is dominated by two classes of sources: Gamma-Ray Bursts (GRBs) and radio loud active galactic nuclei whose jets are pointing at us (blazars). We believe that the radiation we receive from them originates from the transformation of bulk relativistic energy into random energy. Although the mechanisms to produce, collimate and accelerate the jets in these sources are uncertain, it is fruitful to compare the characteristics of both classes of sources in search of enlightening similarities. I will review some general characteristics of radio loud AGNs and GRBs and I will discuss the possibility that both classes of sources can work in the same way. Finally, I will discuss some recent exciting prospects to use blazars to put constraints on the cosmic IR-Optical-UV backgrounds, and to use GRBs as standard candles to measure the Universe.

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20

Partenheimer, Angelina, Ke Fang, Rafael Alves Batista e Rogerio Menezes de Almeida. "Ultra-high-energy Cosmic-Ray Sources Can Be Gamma-Ray Dim". Astrophysical Journal Letters 967, n. 1 (1 maggio 2024): L15. http://dx.doi.org/10.3847/2041-8213/ad4359.

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Abstract Ultra-high-energy cosmic rays (UHECRs), accelerated hadrons that can exceed energies of 1020 eV, are the highest-energy particles ever observed. While the sources producing UHECRs are still unknown, the Pierre Auger Observatory has detected a large-scale dipole anisotropy in the arrival directions of cosmic rays above 8 EeV. In this work, we explore whether resolved gamma-ray sources can reproduce the Auger dipole. We use various Fermi Large Area Telescope catalogs as sources of cosmic rays in CRPropa simulations. We find that in all cases, the simulated dipole has an amplitude significantly larger than that measured by Auger, even when considering large extragalactic magnetic field strengths and optimistic source weighting schemes. Our result implies that the resolved gamma-ray sources are insufficient to account for the population of sources producing the highest-energy cosmic rays, and there must exist a population of UHECR sources that lack gamma-ray emission or are unresolved by the current-generation gamma-ray telescopes.

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21

Kato, S., D. Chen, J. Huang, T. Kawashima, K. Kawata, A. Mizuno, M. Ohnishi et al. "On the Source Contribution to the Galactic Diffuse Gamma Rays above 398 TeV Detected by the Tibet ASγ Experiment". Astrophysical Journal Letters 961, n. 1 (1 gennaio 2024): L13. http://dx.doi.org/10.3847/2041-8213/ad19d2.

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Abstract Potential contribution from gamma-ray sources to the Galactic diffuse gamma rays observed above 100 TeV (sub-PeV energy range) by the Tibet ASγ experiment is an important key to interpreting recent multimessenger observations. This paper reveals a surprising fact: none of the 23 Tibet ASγ diffuse gamma-ray events above 398 TeV within the Galactic latitudinal range of ∣b∣ < 10° come from the 43 sub-PeV gamma-ray sources reported in the 1LHAASO catalog, which proves that these sources are not the origins of the Tibet ASγ diffuse gamma-ray events. No positional overlap between the Tibet ASγ diffuse gamma-ray events and the sub-PeV LHAASO sources currently supports the diffusive nature of the Tibet ASγ diffuse gamma-ray events, although their potential origin in the gamma-ray sources yet unresolved in the sub-PeV energy range cannot be ruled out.

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22

Eichler, David. "Particle Acceleration in High-Energy Gamma-Ray Sources". International Astronomical Union Colloquium 142 (1994): 877–81. http://dx.doi.org/10.1017/s0252921100078246.

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AbstractMany proficient gamma-ray sources show energy spectra that are consistent with E−2 primary spectra. Such sources include recently identified gamma-ray quasars and some gamma-ray bursts. Assuming thick target conversion, this is consistent with shock acceleration, and the dominance of the gamma rays of the luminosity is also consistent with previous predictions of high production efficiency of fresh cosmic rays in shocks. The spectral cutoffs in the gamma rays may offer clues as to whether the high-energy particles are electrons or protons. Resolution of this matter might have implications for the nature of the sources and for theory of shock accelerated electrons.Subject headings: acceleration of particles — gamma rays: bursts — shock waves

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23

Tanimori, Toru. "Galactic TeV Gamma-Ray Sources and Cosmic-Ray Origin". Progress of Theoretical Physics Supplement 151 (2003): 234–39. http://dx.doi.org/10.1143/ptps.151.234.

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24

Paggi, Alessandro, R. D'Abrusco, F. Massaro, M. Landoni, D. Milisavljevic, N. Masetti, F. Ricci et al. "Multi-wavelength selection and identification of gamma-ray blazar candidates". Proceedings of the International Astronomical Union 10, S313 (settembre 2014): 58–63. http://dx.doi.org/10.1017/s1743921315001878.

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AbstractA significant fraction (~ 30%) of the gamma-ray sources detected by the Fermi Gamma-ray Space Telescope is still of unknown origin, being not yet associated with counterparts at lower energies. Many unidentified gamma-ray sources (UGSs) could be blazars, the largest identified population of extragalactic gamma-ray sources and the rarest class of active galactic nuclei. In particular, it has been found that blazars occupy a defined region in WISE three dimensional color space, well separated from that occupied by other sources in which thermal emission prevails. For farther sources with weaker IR emission, additional informations can be obtained combining WISE data with X-ray or radio emission. Alternatively, the low-frequency radio emission can be used for identifying potential gamma-ray candidate blazars. However, optical spectroscopic observations represent the tell-tale tool to confirm the exact nature of these sources. To this end, an extensive observational campaign has been performed with several optical telescopes, aimed at pinpointing the exact nature of gamma-ray candidate blazars selected with the different selection methods mentioned above. The results of this campaign lead to the discovery of 60 new gamma-ray blazars, thus confirming the effectiveness of these selection criteria.

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25

Ghisellini, Gabriele. "X-Ray and Gamma–Ray Emission in Blazars". Symposium - International Astronomical Union 175 (1996): 413–16. http://dx.doi.org/10.1017/s0074180900081286.

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More than 50 sources have been detected by EGRET in 4 years of operations (e.g. von Montigny et al. 1995). Almost all of them show the violent characteristics typical of blazars, such as superluminal motions, strong radio emission mainly produced in a flat spectrum core and large amplitude variability at all frequencies. Interestingly, optical polarization does not seem to be required, since more than 1/3 of the detected sources are less than 3% polarized.

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26

Principe, G., L. Di Venere, M. Orienti, G. Migliori, F. D’Ammando, M. N. Mazziotta e M. Giroletti. "Gamma-ray emission from young radio galaxies and quasars". Monthly Notices of the Royal Astronomical Society 507, n. 3 (17 agosto 2021): 4564–83. http://dx.doi.org/10.1093/mnras/stab2357.

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ABSTRACT According to radiative models, radio galaxies and quasars are predicted to produce gamma rays from the earliest stages of their evolution. Exploring their high-energy emission is crucial for providing information on the most energetic processes, the origin and the structure of the newly born radio jets. Taking advantage of more than 11 yr of Fermi-LAT data, we investigate the gamma-ray emission of 162 young radio sources (103 galaxies and 59 quasars), the largest sample of young radio sources used so far for such a gamma-ray study. We separately analyse each source and perform the first stacking analysis of this class of sources to investigate the gamma-ray emission of the undetected sources. We detect significant gamma-ray emission from 11 young radio sources, 4 galaxies, and 7 quasars, including the discovery of significant gamma-ray emission from the compact radio galaxy PKS 1007+142 (z = 0.213). The cumulative signal of below-threshold young radio sources is not significantly detected. However, it is about one order of magnitude lower than those derived from the individual sources, providing stringent upper limits on the gamma-ray emission from young radio galaxies (Fγ < 4.6 × 10−11 ph cm−2 s−1) and quasars (Fγ < 10.1 × 10−11 ph cm−2 s−1), and enabling a comparison with the models proposed. With this analysis of more than a decade of Fermi-LAT observations, we can conclude that while individual young radio sources can be bright gamma-ray emitters, the collective gamma-ray emission of this class of sources is not bright enough to be detected by Fermi-LAT.

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27

Tavani, Marco. "Non-Blazar Gamma-Ray Variables in the Galactic Plane: A New Class of Gamma-Ray Sources". Highlights of Astronomy 11, n. 2 (1998): 771–74. http://dx.doi.org/10.1017/s1539299600018748.

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AbstractWe discuss recent detections of time-variable gamma-ray sources near the Galactic plane. A new bright gamma-ray transient was detected by EGRET in June 1995 near the Galactic center (GRO J1838-04). Also one of the most interesting unidentified gamma-ray sources in the plane, 2CG 135+1, was recently shown to be variable. Both GRO J1838-04 and 2CG 135+1 share many characteristics: variability of the gamma-ray flux within days/weeks, occasional peak gamma-ray emission of comparable flux (˜ 4 x 10-6ph cm-2s-1), absence of radio-loud spectrally-flat AGNs or prominent radio pulsars within their error boxes, lack of strong X-ray and/or hard X-ray counterparts. These characteristics do not match those of either gamma-ray blazars or isolated pulsars. Therefore, GRO J1838-04 and 2CG 135+1 provide strong evidence for the existence of a new class of variable gamma-ray sources.

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28

Wang, Xiang-Yu, Xiao-Jun Bi, Zhen Cao, Piero Vallania, Han-Rong Wu, Da-Hai Yan e Qiang Yuan. "Chapter 3 Extra-galactic gamma-ray sources *". Chinese Physics C 46, n. 3 (1 marzo 2022): 030003. http://dx.doi.org/10.1088/1674-1137/ac3fa9.

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Abstract Extra-galactic gamma-ray sources, such as gamma-ray bursts, active galactic nuclei, starburst galaxies, are interesting and important targets for LHAASO observations. In this chapter, the prospects of detecting these sources with LHAASO and their physical implications are studied. The upgrade plan for the Water Cherenkov Detector Array (WCDA), which aims to enhance the detectability of relatively lower energy photons, is also presented. In addition, a study on constraining the extragalactic background light with LHAASO observation of blazars is presented.

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29

Hisamoto, Chuck S., e Suneel I. Sheikh. "Spacecraft Navigation Using Celestial Gamma-Ray Sources". Journal of Guidance, Control, and Dynamics 38, n. 9 (settembre 2015): 1765–74. http://dx.doi.org/10.2514/1.g001008.

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30

Quashnock, J. M., e D. Q. Lamb. "Evidence that gamma-ray burst sources repeat". Monthly Notices of the Royal Astronomical Society 265, n. 1 (1 novembre 1993): L59—L64. http://dx.doi.org/10.1093/mnras/265.1.l59.

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31

Best, S., e J. Bazo. "Gamma-ray counterparts of radio astrophysical sources". Journal of Cosmology and Astroparticle Physics 2019, n. 12 (2 dicembre 2019): 004. http://dx.doi.org/10.1088/1475-7516/2019/12/004.

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32

Han, Zhao-Xia, e Li Zhang. "Variability Analysis of EGRET Gamma-Ray Sources". Chinese Journal of Astronomy and Astrophysics 5, n. 3 (giugno 2005): 256–64. http://dx.doi.org/10.1088/1009-9271/5/3/005.

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33

Paredes, Josep M. "Microquasars as High-energy Gamma-ray Sources". Chinese Journal of Astronomy and Astrophysics 5, S1 (31 dicembre 2005): 121–32. http://dx.doi.org/10.1088/1009-9271/5/s1/121.

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34

Wang, V. C., e R. E. Lingenfelter. "Repeating sources of classical gamma-ray bursts". Astrophysical Journal 441 (marzo 1995): 747. http://dx.doi.org/10.1086/175396.

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35

Bulgarelli, A., V. Fioretti, N. Parmiggiani, F. Verrecchia, C. Pittori, F. Lucarelli, M. Tavani et al. "Second AGILE catalogue of gamma-ray sources". Astronomy & Astrophysics 627 (25 giugno 2019): A13. http://dx.doi.org/10.1051/0004-6361/201834143.

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Aims. We present the second AGILE–GRID catalogue (2AGL) of γ-ray sources in the energy range 100 MeV–10 GeV. Methods. With respect to previous AGILE–GRID catalogues, the current 2AGL catalogue is based on the first 2.3 years of science data from the AGILE mission (the so-called pointing mode) and incorporates more data and several analysis improvements, including better calibrations at the event reconstruction level, an updated model for the Galactic diffuse γ-ray emission, a refined procedure for point-like source detection, and the inclusion of a search for extended γ-ray sources. Results. The 2AGL catalogue includes 175 high-confidence sources (above 4σ significance) with their location regions and spectral properties and a variability analysis with four-day light curves for the most significant. Relying on the error region of each source position, including systematic uncertainties, 122 sources are considered as positionally associated with known counterparts at different wavelengths or detected by other γ-ray instruments. Among the identified or associated sources, 62 are active galactic nuclei (AGNs) of the blazar class. Pulsars represent the largest Galactic source class, with 41 associated pulsars, 7 of which have detected pulsation; 8 supernova remnants and 4 high-mass X-ray binaries have also been identified. A substantial number of 2AGL sources are unidentified: for 53 sources no known counterpart is found at different wavelengths. Among these sources, we discuss a subclass of 29 AGILE–GRID–only γ-ray sources that are not present in 1FGL, 2FGL, or 3FGL catalogues; the remaining sources are unidentified in both 2AGL and 3FGL catalogues. We also present an extension of the analysis of 2AGL sources detected in the energy range 50–100 MeV.

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36

MÉSZÁROS, PETER. "GAMMA-RAY BURSTS AS VHE-UHE SOURCES". International Journal of Modern Physics D 17, n. 09 (settembre 2008): 1319–32. http://dx.doi.org/10.1142/s0218271808012875.

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Gamma-ray bursts are capable of accelerating cosmic rays up to GZK energies Ep ~ 1020 eV, which can lead to a flux at Earth comparable to that observed by large EAS arrays such as Auger. The semi-relativistic outflows inferred in GRB-related hypernovae are also likely sources of somewhat lower energy cosmic rays. Leptonic processes, such as synchrotron and inverse Compton, as well as hadronic processes, can lead to GeV-TeV gamma-rays measurable by GLAST, AGILE, or ACTs, providing useful probes of the burst physics and model parameters. Photo-meson interactions also produce neutrinos at energies ranging from sub-TeV to EeV, which will be probed with forthcoming experiments such as IceCube, ANITA and KM3NeT. This would provide information about the fundamental interaction physics, the acceleration mechanism, the nature of the sources and their environment.

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Asano, Katsuaki, e Kohta Murase. "Gamma-Ray Bursts as Multienergy Neutrino Sources". Advances in Astronomy 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/568516.

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We review theoretical models for nonelectromagnetic emission, mainly neutrinos and cosmic rays, from gamma-ray bursts (GRBs). In various stages of the relativistic jet propagation, cosmic-ray ion acceleration and subsequent neutrino emission are expected. GRBs are popular candidate sources of the highest-energy cosmic rays, and their prompt phase has been most widely discussed. IceCube nondetection of PeV neutrinos coincident with GRBs has put interesting constraints on the standard theoretical prediction. The GRB-UHECR hypothesis can critically be tested by future observations. We also emphasize the importance of searches for GeV-TeV neutrinos, which are expected in the precursor/orphan or prompt phase, and lower-energy neutrinos would be more guaranteed and their detections even allow us to probe physics inside a progenitor star. Not only classical GRBs but also low-power GRBs and transrelativistic supernovae can be promising sources of TeV-PeV neutrinos, and we briefly discuss implications for the cumulative neutrino background discovered by IceCube.

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38

Vernetto, S. "Gamma ray sources observed with ARGO-YBJ". Nuclear Physics B - Proceedings Supplements 239-240 (giugno 2013): 98–103. http://dx.doi.org/10.1016/j.nuclphysbps.2013.05.016.

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39

Kaufman Bernadó, M. M., G. E. Romero e I. F. Mirabel. "Precessing microblazars and unidentified gamma-ray sources". Astronomy & Astrophysics 385, n. 2 (aprile 2002): L10—L13. http://dx.doi.org/10.1051/0004-6361:20020251.

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40

McLaughlin, M. A., J. R. Mattox, J. M. Cordes e D. J. Thompson. "Variability of CGRO/EGRET Gamma Ray Sources". International Astronomical Union Colloquium 160 (1996): 357–58. http://dx.doi.org/10.1017/s0252921100041889.

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We have developed a method for quantifying the flux variabilities of high energy gamma ray sources. We have applied this method to 128 sources listed in the second catalog of sources detected with the Energetic Gamma Ray Experiment Telescope (EGRET) (Thompson et. al. 1995). These sources include the Large Magellanic Cloud, 5 pulsars, 41 active galactic nuclei (AGN), and 81 sources not yet identified with known objects.Our data include photon maps (E > 100 MeV) from 134 EGRET viewing periods spanning a roughly 3year period. Each source was observed in 3-20 viewing periods ranging from a few days to 3 weeks in length. For each observation, a source flux was calculated using the method of maximum likelihood (Mattoxet al. 1996) which simultaneously estimates the strength of the Galactic and isotropic diffuse emission, and that of a point source distributed as the EGRET point spread function.

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41

Pizzichini, Graziella, e M. Rosaria Cristallo. "Identification of X and Gamma-Ray sources". Advances in Space Research 11, n. 8 (gennaio 1991): 49–53. http://dx.doi.org/10.1016/0273-1177(91)90149-e.

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42

Mendonça, J. T., e A. Serbeto. "Gamma ray sources using imperfect relativistic mirrors". Physics of Plasmas 15, n. 11 (novembre 2008): 113105. http://dx.doi.org/10.1063/1.3001690.

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43

Burgess, J. Michael, Damien Bégué, Jochen Greiner, Dimitrios Giannios, Ana Bacelj e Francesco Berlato. "Gamma-ray bursts as cool synchrotron sources". Nature Astronomy 4, n. 2 (21 ottobre 2019): 174–79. http://dx.doi.org/10.1038/s41550-019-0911-z.

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44

Petry, D., V. Beckmann, H. Halloin e A. Strong. "Soft gamma-ray sources detected by INTEGRAL". Astronomy & Astrophysics 507, n. 1 (15 settembre 2009): 549–71. http://dx.doi.org/10.1051/0004-6361/200912844.

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45

Shirokov, S. I., A. A. Raikov e Yu V. Baryshev. "Spatial Distribution of Gamma-Ray Burst Sources". Astrophysics 60, n. 4 (27 novembre 2017): 484–96. http://dx.doi.org/10.1007/s10511-017-9500-y.

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46

Murphy, D. W., S. J. Tingay, R. A. Preston, D. L. Meier, D. L. Jones, P. G. Edwards, M. E. Costa et al. "VLBI of Southern EGRET Identifications". International Astronomical Union Colloquium 164 (1998): 55–56. http://dx.doi.org/10.1017/s025292110004450x.

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Abstract (sommario):

AbstractWe have undertaken VLBI observations of 8 Southern Hemisphere EGRET radio sources. Using our data as well as data obtained from the literature we have examined the difference in radio properties between gamma-ray loud and gamma-ray quiet radio sources. In particular, we find no evidence that gamma-ray loud radio sources lie preferentially in sources with straight radio jets as has been suggested.

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47

Guillemot, L. "Radio counterparts of gamma-ray pulsars". Proceedings of the International Astronomical Union 8, S291 (agosto 2012): 87–92. http://dx.doi.org/10.1017/s1743921312023241.

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Abstract (sommario):

AbstractObservations of pulsars with the Large Area Telescope (LAT) on the Fermi satellite have revolutionized our view of the gamma-ray pulsar population. For the first time, a large number of young gamma-ray pulsars have been discovered in blind searches of the LAT data. More generally, the LAT has discovered many new gamma-ray sources whose properties suggest that they are powered by unknown pulsars. Radio observations of gamma-ray sources have been key to the success of pulsar studies with the LAT. For example, radio observations of LAT-discovered pulsars provide constraints on the relative beaming fractions, which are crucial for pulsar population studies. Also, radio searches of LAT sources with no known counterparts have been very efficient, with the discovery of over forty millisecond pulsars. I review radio follow-up studies of LAT-discovered pulsars and unidentified sources, and discuss some of the implications of the results.

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48

Browne, P. F. "A theory for gamma ray and X-ray burst sources". Astrophysics and Space Science 231, n. 1-2 (settembre 1995): 431–36. http://dx.doi.org/10.1007/bf00658664.

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49

Mohammed, Mohammed Siddig H., Abdulsalam Alhawsawi, M. S. Aljohani, Mohammed M. Damoom, Essam M. Banoqitah e Ezzat Elmoujarkach. "Prompt gamma-ray methods for industrial process evaluation: A simulation study". Nukleonika 67, n. 1 (17 febbraio 2022): 11–18. http://dx.doi.org/10.2478/nuka-2022-0001.

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Abstract (sommario):

Abstract Radioisotope applications in industrial process inspection and evaluation using gamma-ray emitters provide otherwise unavailable information. Offering alternative gamma-ray sources can support the technology by complementing sources’ availability and radiation safety. This work proposes to replace gamma-ray from radioisotopes with prompt gamma-ray from the interaction of neutrons with stable isotopes injected into the industrial process or with the structural material of the industrial process equipment. Monte Carlo N-Particle Transport Code (MCNP5) was used to simulate the irradiation of two-phase flow pipes by 252Cf neutron source. Two simulations were run for each pipe, with and without mixing the liquid phase with the stable isotope 157Gd. The detected gamma-ray spectra were analysed, and images of the two phases inside the pipes were produced. The images were compared to images obtained from simulations of gamma transmission measurement using 60Co. Furthermore, results for prompt gamma computed tomography (CT) were presented and discussed. The studies’ outcomes indicate the potential of prompt gamma-ray to carry out the sealed sources applications of gamma transmission measurements and imaging.

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50

Hudec, René, e Miloš Klíma. "Identification and Analyses in Optical Light of Gamma-Ray Sources with Astronomical Archival Plates". Advances in Astronomy 2010 (2010): 1–6. http://dx.doi.org/10.1155/2010/618975.

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Abstract (sommario):

The ESA INTEGRAL satellite (International Gamma Ray Laboratory) launched in October 2002 continues to deliver valuable data about the gamma-ray sky. Nearly 450 gamma-ray sources have been detected so far mainly by the IBIS onboard instrument, and others are expected in the future. The first 3.5 years of INTEGRAL public and Core Program data have revealed more than 400 sources and this number is expected to increase to more than 500 in the future (Bird et al. 2007). Alternative method to identify and to analyze INTEGRAL gamma-ray sources using optical light and astronomical archival plates is described, together with additional results from analyses of high-energy sources in these databases.

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