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1. The Fermi-LAT Lightcurve Repository

Author

S. Abdollahi, M. Ajello, L. Baldini, J. Ballet, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. Bonino, A. Brill, P. Bruel, E. Burns, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, N. Cibrario, S. Ciprini, P. Cristarella Orestano, M. Crnogorcevic, S. Cutini, F. D’Ammando, S. De Gaetano, S. W. Digel, N. Di Lalla, L. Di Venere, A. Domínguez, V. Fallah Ramazani, S. J. Fegan, E. C. Ferrara, A. Fiori, H. Fleischhack, A. Franckowiak, Y. Fukazawa, P. Fusco, V. Gammaldi, F. Gargano, S. Garrappa, C. Gasbarra, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, M. Gustafsson, E. Hays, D. Horan, X. Hou, G. Jóhannesson, M. Kerr, D. Kocevski, M. Kuss, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, L. Lorusso, B. Lott, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, I. Mereu, M. Meyer, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, G. Panzarini, J. S. Perkins, M. Persic, M. Pesce-Rollins, R. Pillera, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, M. Sánchez-Conde, P. M. Saz Parkinson, Jeff Scargle, L. Scotton, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, D. J. Thompson, D. F. Torres, J. Valverde, T. Venters, Z. Wadiasingh, S. Wagner, and K. Wood

Subjects
Gamma-ray astronomy, Active galactic nuclei, Light curves, Astrophysics, QB460-466
Abstract

The Fermi Large Area Telescope (LAT) lightcurve repository (LCR) is a publicly available, continually updated library of gamma-ray lightcurves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality lightcurves binned on timescales of 3, 7, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 yr of Fermi-LAT observations. The repository consists of lightcurves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multimessenger communities by allowing users to search LAT data quickly to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal.

Published
2023
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4. The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope

Author

M. Ajello, R. Angioni, M. Axelsson, J. Ballet, G. Barbiellini, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, E. Bissaldi, E. D. Bloom, R. Bonino, E. Bottacini, P. Bruel, S. Buson, F. Cafardo, R. A. Cameron, E. Cavazzuti, S. Chen, C. C. Cheung, S. Ciprini, D. Costantin, S. Cutini, F. D’Ammando, P. de la Torre Luque, R. de Menezes, F. de Palma, A. Desai, N. Di Lalla, L. Di Venere, A. Domínguez, F. Fana Dirirsa, E. C. Ferrara, J. Finke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Garrappa, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, S. Harita, E. Haywood, D. Horan, R. Itoh, G. Jóhannesson, M. Kovac’evic’, F. Krauss, M. Kreter, M. Kuss, S. Larsson, C. Leto, J. Li, I. Liodakis, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, S. Maldera, A. Manfreda, G. Martí-Devesa, F. Massaro, M. N. Mazziotta, I. Mereu, M. Meyer, G. Migliori, N. Barrios, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, R. Nemmen, E. Nuss, L. S. Ojha, R. Ojha, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, V. S. Paliya, Z. Pei, H. Peña-Herazo, M. Persic, M. Pesce-Rollins, L. Petrov, F. Piron, H. Poon, G. Principe, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, F. K. Schinzel, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, Y. Tachibana, D. J. Thompson, D. F. Torres, E. Torresi, E. Troja, J. Valverde, P. van Zyl, and M. Yassine

Subjects
Astrophysics, Astronomy
Abstract

The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains $2863$ objects located at high Galactic latitudes (| b| > 10^9). It includes 85% more sources than the previous 3LAC catalog based on 4 yr of data. AGNs represent at least 79% of the high-latitude sources in the fourth Fermi-Large Area Telescope Source Catalog (4FGL), which covers the energy range from 50 MeV to 1 TeV. In addition, 344 gamma-ray AGNs are found at low Galactic latitudes. Most of the 4LAC AGNs are blazars (98%), while the remainder are other types of AGNs. The blazar population consists of 24% Flat Spectrum Radio Quasars (FSRQs), 38% BL Lac-type objects, and 38% blazar candidates of unknown types (BCUs). On average, FSRQs display softer spectra and stronger variability in the gamma-ray band than BL Lacs do, confirming previous findings. All AGNs detected by ground-based atmospheric Cerenkov telescopes are also found in the 4LAC.

Published
2020
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5. Fermi Large Area Telescope Fourth Source Catalog

Author

S. Abdollahi, F. Acero, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, J. M. Casandjian, D. Castro, E. Cavazzuti, E. Charles, S. Chaty, S. Chen, C. C. Cheung, G. Chiaro, S. Ciprini, J. Cohen-Tanugi, L. R. Cominsky, J. Coronado-Blázquez, D. Costantin, A. Cuoco, S. Cutini, F. D'Ammando, M. DeKlotz, P. de la Torre Luque, F. de Palma, A. Desai, S. W. Digel, N. Di Lalla, M. Di Mauro, L. Di Venere, A. Dominguez, D. Dumora, F. Fana Dirirsa, S. J. Fegan, E. C. Ferrara, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, D. Green, I. A. Grenier, S. Griffin, M.-H. Grondin, J. E. Grove, S. Guiriec, A. K. Harding, K. Hayashi, E. Hays, J. W. Hewitt, D. Horan, G. Jóhannesson, T. J. Johnson, T. Kamae, M. Kerr, D. Kocevski, M. Kovac’evic’, M. Kuss, D. Landriu, S. Larsson, L. Latronico, M. Lemoine-Goumard, J. Li, I. Liodakis, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, S. Maldera, D. Malyshev, A. Manfreda, E. J. Marchesini, L. Marcotulli, G. Martí-Devesa, P. Martin, F. Massaro, M. N. Mazziotta, J. E. McEnery, I. Mereu, M. Meyer, P. F. Michelson, N. Mirabal, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, R. Ojha, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, M. Palatiello, V. S. Paliya, D. Paneque, Z. Pei, H. Peña-Herazo, J. S. Perkins, M. Persic, M. Pesce-Rollins, V. Petrosian, L. Petrov, F. Piron, H. Poon, T. A. Porter, G. Principe, S. Raino', R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, Q. Remy, T. Reposeur, R. W. Romani, P. M. Saz Parkinson, F. K. Schinzel, D. Serini, C. Sgro', E. J. Siskind, D. A. Smith, G. Spandre, P. Spinelli, A. W. Strong, D. J. Suson, H. Tajima, M. N. Takahashi, D. Tak, J. B. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, E. Torresi, J. Valverde, B. Van Klaveren, P. van Zyl, K. Wood, M. Yassine, and G. Zaharijas

Subjects
Astrophysics
Abstract

We present the fourth Fermi Large Area Telescope catalog (4FGL) of gamma-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the deepest yet in this energy range. Relative to the 3FGL catalog, the 4FGL catalog has twice as much exposure as well as a number of analysis improvements, including an updated model for the Galactic diffuse gamma-ray emission, and two sets of light curves (one-year and two-month intervals). The 4FGL catalog includes 5064 sources above 4 sigma significance, for which we provide localization and spectral properties. Seventy-five sources are modeled explicitly as spatially extended, and overall, 358 sources are considered as identified based on angular extent, periodicity, or correlated variability observed at other wavelengths. For 1336 sources, we have not found plausible counterparts at other wavelengths. More than 3130 of the identified or associated sources are active galaxies of the blazar class, and 239 are pulsars.

Published
2020
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6. Fermi and Swift Observations of GRB 190114C: Tracing the Evolution of High-energy Emission from Prompt to Afterglow

Author

M. Ajello, M. Arimoto, M. Axelsson, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, R. Buehler, E. Burns, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, E. Cavazzuti, S. Chen, G. Chiaro, S. Ciprini, J. Cohen-Tanugi, D. Costantin, S. Cutini, F.D’Ammando, M. DeKlotz, P. de la Torre Luque, F. de Palma, A. Desai, N. Di Lalla, L. Di Venere, F. Fana Dirirsa, S. J. Fegan, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, R. Gill, F. Giordano, M. Giroletti, J. Granot, D. Green, I. A. Grenier, M.-H. Grondin, S. Guiriec, E. Hays, D. Horan, G. Jóhannesson, D. Kocevski, M. Kovac’evic’, M. Kuss, S. Larsson, L. Latronico, M. Lemoine-Goumard, J.Li, I. Liodakis, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, S. Maldera, D. Malyshev, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, J. E. McEnery, I. Mereu, M. Meyer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, N. Omodei, M. Orienti, E. Orlando, M. Palatiello, V. S. Paliya, D. Paneque, Z. Pei, M. Persic, M. Pesce-Rollins, V. Petrosian, F. Piron, H. Poon, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, F. Ryde, P. M. Saz Parkinson, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, H. Tajima, K. Takagi, M. N. Takahashi, D. Tak, J. B. Thayer, D. J. Thompson, D. F. Torres, E. Troja, J. Valverde, B. Van Klaveren, K. Wood, M. Yassine, G. Zaharijas, B. Mailyan, P. N. Bhat, M. S. Briggs, W. Cleveland, M. Giles, A. Goldstein, M. Hui, Christian Malacaria, R. Preece, O. J. Roberts, P. Veres, C. Wilson-Hodge, A. von Kienlin, S. B. Cenko, P. O’Brien, A. P. Beardmore, A. Lien, J. P. Osborne, A. Tohuvavohu, V. D’Elia, A.D’Aì, M. Perri, J. Gropp, N. Klingler, M. Capalbi, G. Tagliaferri, M. Stamatikos, and M. De Pasquale

Subjects
Astronomy
Abstract

We report on the observations of gamma-ray burst (GRB) 190114C by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. The prompt gamma-ray emission was detected by the Fermi GRB Monitor (GBM), the Fermi Large Area Telescope (LAT), and the Swift Burst Alert Telescope (BAT) and the long-lived afterglow emission was subsequently observed by the GBM, LAT, Swift X-ray Telescope (XRT), and Swift UV Optical Telescope. The early-time observations reveal multiple emission components that evolve independently, with a delayed power-law component that exhibits significant spectral attenuation above 40 MeV in the first few seconds of the burst. This power-law component transitions to a harder spectrum that is consistent with the afterglow emission observed by the XRT at later times. This afterglow component is clearly identifiable in the GBM and BAT light curves as a slowly fading emission component on which the rest of the prompt emission is superimposed. As a result, we are able to observe the transition from internal-shock- to external-shock-dominated emission. We find that the temporal and spectral evolution of the broadband afterglow emission can be well modeled as synchrotron emission from a forward shock propagating into a wind-like circumstellar environment. We estimate the initial bulk Lorentz factor using the observed high-energy spectral cutoff. Considering the onset of the afterglow component, we constrain the deceleration radius at which this forward shock begins to radiate in order to estimate the maximum synchrotron energy as a function of time. We find that even in the LAT energy range, there exist high-energy photons that are in tension with the theoretical maximum energy that can be achieved through synchrotron emission from a shock. These violations of the maximum synchrotron energy are further compounded by the detection of very high-energy (VHE) emission above 300 GeV by MAGIC concurrent with our observations. We conclude that the observations of VHE photons from GRB 190114C necessitates either an additional emission mechanism at very high energies that is hidden in the synchrotron component in the LAT energy range, an acceleration mechanism that imparts energy to the particles at a rate that is faster than the electron synchrotron energy-loss rate, or revisions of the fundamental assumptions used in estimating the maximum photon energy attainable through the synchrotron process.

Published
2020
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8. A gamma-ray determination of the Universe’s star formation history

Author

S. Abdollahi, M. Ackermann, M. Ajello, W. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, J. Becerra González, R. Bellazzini, E. Bissaldi, R. Blandford, E. Bloom, R. Bonino, E. Bottacini, S. Buson, J. Bregeon, P. Bruel, R. Buehler, R. Cameron, R. Caputo, P. A. Caraveo, E. Cavazzuti, E. Charles, S. Chen, T. Cheung, G. Chiaro, S. Ciprini, J. Cohen-Tanugi, L. Cominsky, J. Conrad, D. Costantin, S. Cutini, F. D’Ammando, F. de Palma, A. Desai, S. Digel, N. Di Lalla, M. Di Mauro, L. Di Venere, A. Domínguez, C. Favuzzi, S. Fegan, J. Finke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, G. Gallardo Romero, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. Grenier, L. Guillemot, S. Guiriec, D. H. Hartmann, E. Hays, K. Helgason, D. Horan, G. Jóhannesson, D. Kocevski, M. Kuss, S. Larsson, L. Latronico, J. Li, F. Longo, F. Loparco, B. Lott, M. Lovellette, P. Lubrano, G. Madejski, J. Magill, S. Maldera, A. Manfreda, L. Marcotulli, M. Mazziotta, J. McEnery, M. Meyer, P. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. Moskalenko, M. Negro, E. Nuss, R. Ojha, N. Omodei, M. Orienti, E. Orlando, J. Ormes, M. Palatiello, V. Paliya, D. Paneque, J. Perkins, M. Persic, M. Pesce-Rollins, V. Petrosian, F. Piron, T. Porter, J. R. Primack, G. Principe, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, P. Saz Parkinson, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, M. Takahashi, J. Thayer, L. Tibaldo, D. F. Torres, E. Torresi, G. Tosti, A. Tramacere, E. Troja, J. V. Valverde, G. Vianello, M. Vogel, K. Wood, and G. Zaharijas

Published
2018
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9. Gamma Rays from Fast Black-hole Winds

Author

M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, P. Bruel, S. Buson, R. A. Cameron, D. Caprioli, R. Caputo, E. Cavazzuti, G. Chartas, S. Chen, C. C. Cheung, G. Chiaro, D. Costantin, S. Cutini, F. D’Ammando, P. de la Torre Luque, F. de Palma, A. Desai, R. Diesing, N. Di Lalla, F. Dirirsa, L. Di Venere, A. Domínguez, S. J. Fegan, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, D. Hartmann, D. Horan, G. Jóhannesson, C. Karwin, M. Kerr, M. Kovačević, M. Kuss, S. Larsson, L. Latronico, M. Lemoine-Goumard, J. Li, I. Liodakis, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, S. Marchesi, L. Marcotulli, G. Martí-Devesa, M. N. Mazziotta, I. Mereu, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, N. Omodei, M. Orienti, E. Orlando, V. Paliya, D. Paneque, Z. Pei, M. Persic, M. Pesce-Rollins, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, A. Reimer, O. Reimer, P. M. Saz Parkinson, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, D. Tak, D. F. Torres, E. Troja, K. Wood, G. Zaharijas, and J. Zrake

Published
2021
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11. The Fermi-LAT Light Curve Repository

Author

S. Abdollahi, M. Ajello, L. Baldini, J. Ballet, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. Bonino, A. Brill, P. Bruel, E. Burns, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, N. Cibrario, S. Ciprini, P. Cristarella Orestano, M. Crnogorcevic, S. Cutini, F. D’Ammando, S. De Gaetano, S. W. Digel, N. Di Lalla, L. Di Venere, A. Domínguez, V. Fallah Ramazani, S. J. Fegan, E. C. Ferrara, A. Fiori, H. Fleischhack, A. Franckowiak, Y. Fukazawa, P. Fusco, V. Gammaldi, F. Gargano, S. Garrappa, C. Gasbarra, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, M. Gustafsson, E. Hays, D. Horan, X. Hou, G. Jóhannesson, M. Kerr, D. Kocevski, M. Kuss, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, L. Lorusso, B. Lott, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, I. Mereu, M. Meyer, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, G. Panzarini, J. S. Perkins, M. Persic, M. Pesce-Rollins, R. Pillera, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, M. Sánchez-Conde, P. M. Saz Parkinson, Jeff Scargle, L. Scotton, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, D. J. Thompson, D. F. Torres, J. Valverde, T. Venters, Z. Wadiasingh, S. Wagner, K. Wood, and UAM. Departamento de Física Teórica

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Active galactic nuclei, Light Curves (918), Gamma-ray astronomy, Space and Planetary Science, Física, FOS: Physical sciences, Gamma-ray astronomy, Active galactic nuclei, Light curves, Astrophysics - High Energy Astrophysical Phenomena, Gamma-Ray Astronomy (628), Astronomy and Astrophysics, Active Galactic Nuclei (16), Light curves, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiere, The Fermi Large Area Telescope (LAT) lightcurve repository (LCR) is a publicly available, continually updated library of gamma-ray lightcurves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality lightcurves binned on timescales of 3, 7, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 yr of Fermi-LAT observations. The repository consists of lightcurves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multimessenger communities by allowing users to search LAT data quickly to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal, M.N. and J.V. acknowledge that the material is based upon work supported by NASA under award number 80GSFC21M0002. D.K. and M.N. acknowledge support to this work from NASA Fermi GI Program under grant number 80NSSC23K0242. A.B. is supported by the NASA Postdoctoral Program at NASA Goddard Space Flight Center, administered by Oak Ridge Associated Universities. INFN and ASI personnel performed in part under ASI-INFN Agreements No. 2021-43-HH.0. Work at NRL is supported by NASA. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515

Published
2023
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12. Unresolved Gamma-Ray Sky through its Angular Power Spectrum

Author

M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, R. Buehler, E. Burns, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, E. Cavazzuti, S. Chen, G. Chiaro, S. Ciprini, D. Costantin, A. Cuoco, S. Cutini, F. D’Ammando, P. de la Torre Luque, F. de Palma, A. Desai, S. W. Digel, N. Di Lalla, M. Di Mauro, L. Di Venere, F. Fana Dirirsa, C. Favuzzi, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, L. Guillemot, S. Guiriec, D. Horan, G. Jóhannesson, M. Kuss, S. Larsson, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, P. Lubrano, J. D. Magill, S. Maldera, D. Malyshev, A. Manfreda, M. N. Mazziotta, I. Mereu, P. F. Michelson, W. Mitthumsiri, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, M. Orienti, E. Orlando, M. Palatiello, V. S. Paliya, D. Paneque, M. Persic, M. Pesce-Rollins, V. Petrosian, F. Piron, T. A. Porter, G. Principe, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, M. Takahashi, J. B. Thayer, L. Tibaldo, D. F. Torres, E. Troja, T. M. Venters, G. Vianello, K. Wood, M. Yassine, G. Zaharijas, S. Ammazzalorso, N. Fornengo, and M. Regis

Published
2018
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17. AutoSourceID-Light Fast optical source localization via U-Net and Laplacian of Gaussian

Author

F. Stoppa, P. Vreeswijk, S. Bloemen, S. Bhattacharyya, S. Caron, G. Jóhannesson, R. Ruiz de Austri, C. van den Oetelaar, G. Zaharijas, P. J. Groot, E. Cator, and G. Nelemans

Subjects
stars, Science & Technology, CONVOLUTION, Astronomy, data analysis, FOS: Physical sciences, imaging, Astronomy and Astrophysics, Astronomy & Astrophysics, miscellaneous, methods, image processing, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), DESIGN, Space and Planetary Science, Physical Sciences, astronomical databases, High Energy Physics, Astrophysics - Instrumentation and Methods for Astrophysics, techniques, Instrumentation and Methods for Astrophysics (astro-ph.IM), Mathematics
Abstract

Aims. With the ever-increasing survey speed of optical wide-field telescopes and the importance of discovering transients when they are still young, rapid and reliable source localization is paramount. We present AutoSourceID-Light (ASID-L), an innovative framework that uses computer vision techniques that can naturally deal with large amounts of data and rapidly localize sources in optical images. Methods. We show that the ASID-L algorithm based on U-shaped networks and enhanced with a Laplacian of Gaussian filter provides outstanding performance in the localization of sources. A U-Net network discerns the sources in the images from many different artifacts and passes the result to a Laplacian of Gaussian filter that then estimates the exact location. Results. Using ASID-L on the optical images of the MeerLICHT telescope demonstrates the great speed and localization power of the method. We compare the results with SExtractor and show that our method outperforms this more widely used method. ASID-L rapidly detects more sources not only in low- and mid-density fields, but particularly in areas with more than 150 sources per square arcminute. The training set and code used in this paper are publicly available.

Published
2022

18. Cosmic-ray electron-positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope

Author

S. Abdollahi, M. Ackermann, M. Ajello, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, E. D. Bloom, R. Bonino, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, R. A. Cameron, R. Caputo, M. Caragiulo, D. Castro, E. Cavazzuti, C. Cecchi, A. Chekhtman, S. Ciprini, J. Cohen-Tanugi, F. Costanza, A. Cuoco, S. Cutini, F. D’Ammando, F. de Palma, R. Desiante, S. W. Digel, N. Di Lalla, M. Di Mauro, L. Di Venere, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, W. B. Focke, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, L. Guillemot, S. Guiriec, A. K. Harding, T. Jogler, G. Jóhannesson, T. Kamae, M. Kuss, G. La Mura, L. Latronico, F. Longo, F. Loparco, P. Lubrano, S. Maldera, D. Malyshev, A. Manfreda, M. N. Mazziotta, P. F. Michelson, N. Mirabal, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, E. Orlando, D. Paneque, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, T. A. Porter, G. Principe, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, C. Sgrò, D. Simone, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, H. Tajima, J. B. Thayer, L. Tibaldo, D. F. Torres, E. Troja, M. Wood, A. Worley, G. Zaharijas, and S. Zimmer

Published
2017
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19. Search for Cosmic-Ray Electron and Positron Anisotropies with Seven Years of Fermi Large Area Telescope Data

Author

S. Abdollahi, M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, L. Baldini, G. Barbiellini, R. Bellazzini, E. Bissaldi, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, P. Bruel, S. Buson, M. Caragiulo, E. Cavazzuti, A. Chekhtman, S. Ciprini, F. Costanza, A. Cuoco, S. Cutini, F. D’Ammando, F. de Palma, R. Desiante, S. W. Digel, N. Di Lalla, M. Di Mauro, L. Di Venere, B. Donaggio, P. S. Drell, C. Favuzzi, W. B. Focke, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, S. Guiriec, A. K. Harding, T. Jogler, G. Jóhannesson, T. Kamae, M. Kuss, S. Larsson, L. Latronico, J. Li, F. Longo, F. Loparco, P. Lubrano, J. D. Magill, D. Malyshev, A. Manfreda, M. N. Mazziotta, M. Meehan, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, M. Negro, E. Nuss, T. Ohsugi, N. Omodei, D. Paneque, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, G. Principe, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, C. Sgrò, D. Simone, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, A. W. Strong, H. Tajima, J. B. Thayer, D. F. Torres, E. Troja, J. Vandenbroucke, G. Zaharijas, and S. Zimmer

Published
2017
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20. Investigating the Nature of Late-Time High-Energy GRB Emission Through Joint

Author

M, Ajello, L, Baldini, G, Barbiellini, D, Bastieri, R, Bellazzini, E, Bissaldi, R D, Blandford, R, Bonino, E, Bottacini, J, Bregeon, P, Bruel, R, Buehler, R A, Cameron, R, Caputo, P A, Caraveo, G, Chiaro, S, Ciprini, J, Cohen-Tanugi, D, Costantin, F, D'Ammando, F, DE Palma, N, DI Lalla, M, DI Mauro, L, DI Venere, A, Domínguez, C, Favuzzi, A, Franckowiak, Y, Fukazawa, S, Funk, P, Fusco, F, Gargano, D, Gasparrini, N, Giglietto, F, Giordano, M, Giroletti, D, Green, I A, Grenier, S, Guiriec, C, Holt, D, Horan, G, Jóhannesson, D, Kocevski, M, Kuss, G, LA Mura, S, Larsson, J, Li, F, Longo, F, Loparco, P, Lubrano, J D, Magill, S, Maldera, A, Manfreda, M N, Mazziotta, P F, Michelson, T, Mizuno, M E, Monzani, A, Morselli, M, Negro, E, Nuss, N, Omodei, M, Orienti, E, Orlando, V S, Paliya, J S, Perkins, M, Persic, M, Pesce-Rollins, F, Piron, G, Principe, J L, Racusin, S, Rainò, R, Rando, M, Razzano, S, Razzaque, A, Reimer, O, Reimer, C, Sgrò, E J, Siskind, G, Spandre, P, Spinelli, D, Tak, J B, Thayer, D F, Torres, G, Tosti, J, Valverde, M, Vogel, and K, Wood

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Article
Abstract

We use joint observations by the Neil Gehrels Swift X-ray Telescope (XRT) and the Fermi Large Area Telescope (LAT) of gamma-ray burst (GRB) afterglows to investigate the nature of the long-lived high-energy emission observed by Fermi LAT. Joint broadband spectral modeling of XRT and LAT data reveal that LAT non-detections of bright X-ray afterglows are consistent with a cooling break in the inferred electron synchrotron spectrum below the LAT and/or XRT energy ranges. Such a break is sufficient to suppress the high-energy emission so as to be below the LAT detection threshold. By contrast, LAT-detected bursts are best fit by a synchrotron spectrum with a cooling break that lies either between or above the XRT and LAT energy ranges. We speculate that the primary difference between GRBs with LAT afterglow detections and the non-detected population may be in the type of circumstellar environment in which these bursts occur, with late-time LAT detections preferentially selecting GRBs that occur in low wind-like circumburst density profiles. Furthermore, we find no evidence of high-energy emission in the LAT-detected population significantly in excess of the flux expected from the electron synchrotron spectrum fit to the observed X-ray emission. The lack of excess emission at high energies could be due to a shocked external medium in which the energy density in the magnetic field is stronger than or comparable to that of the relativistic electrons behind the shock, precluding the production of a dominant synchrotron self-Compton (SSC) component in the LAT energy range. Alternatively, the peak of the SSC emission could be beyond the 0.1–100 GeV energy range considered for this analysis.

Published
2022

21. The Steady-State Multi-TeV Diffuse Gamma-Ray Emission Predicted with GALPROP and Prospects for the Cherenkov Telescope Array

Author

P D Marinos, G P Rowell, T A Porter, and G Jóhannesson

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

Cosmic Rays (CRs) interact with the diffuse gas, radiation, and magnetic fields in the interstellar medium (ISM) to produce electromagnetic emissions that are a significant component of the all-sky flux across a broad wavelength range. The Fermi Large Area Telescope (LAT) has measured these emissions at GeV $\gamma$-ray energies with high statistics. Meanwhile, the High-Energy Stereoscopic System (H.E.S.S.) telescope array has observed large-scale Galactic diffuse emission in the TeV $\gamma$-ray energy range. The emissions observed at GeV and TeV energies are connected by the common origin of the CR particles injected by the sources, but the energy dependence of the mixture from the general ISM (true `diffuse'), those emanating from the relatively nearby interstellar space about the sources, and the sources themselves, is not well understood. In this paper, we investigate predictions of the broadband emissions using the GALPROP code over a grid of steady-state 3D models that include variations over CR sources, and other ISM target distributions. We compare, in particular, the model predictions in the VHE ($\geq$100 GeV) $\gamma$-ray range with the H.E.S.S. Galactic plane survey (HGPS) after carefully subtracting emission from catalogued $\gamma$-ray sources. Accounting for the unresolved source contribution, and the systematic uncertainty of the HGPS, we find that the GALPROP model predictions agree with lower estimates for the HGPS source-subtracted diffuse flux. We discuss the implications of the modelling results for interpretation of data from the next generation Cherenkov Telescope Array (CTA)., Comment: 14 pages, 12 figures, Accepted in MNRAS

Published
2022
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22. Cosmic-Ray Propagation in Light of the Recent Observation of Geminga

Author

G. Jóhannesson, Igor V. Moskalenko, and T. A. Porter

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010504 meteorology & atmospheric sciences, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Astronomy and Astrophysics, Cosmic ray, Astrophysics, 01 natural sciences, Article, Interstellar medium, Pulsar, Space and Planetary Science, 0103 physical sciences, Diffusion (business), Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Cherenkov radiation, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Fermi Gamma-ray Space Telescope
Abstract

The High Altitude Water Cherenkov (HAWC) telescope recently observed extended emission around the Geminga and PSR~B0656+14 pulsar wind nebulae (PWNe). These observations have been used to estimate cosmic-ray (CR) diffusion coefficients near the PWNe that appear to be more than two orders of magnitude smaller than that typically derived for the interstellar medium from the measured abundances of secondary species in CRs. Two-zone diffusion models have been proposed as a solution to this discrepancy, where the slower diffusion zone (SDZ) is confined to a small region around the PWN. Such models are shown to successfully reproduce the HAWC observations of the Geminga PWN while retaining consistency with other CR data. It is found that the size of the SDZ influences the predicted positron flux and the spectral shape of the extended $\gamma$-ray emission at lower energies that can be observed with the {\it Fermi} Large Area Telescope ({\it Fermi} LAT). If the two observed PWNe are not unique, then it is likely that there are similar pockets of slow diffusion around many CR sources elsewhere in the Milky Way. The consequences of such picture for Galactic CR propagation is explored., Comment: 13 pages, 9 figures, submitted to ApJ

Published
2021

23. The Discovery of a Low-energy Excess in Cosmic-Ray Iron: Evidence of the Past Supernova Activity in the Local Bubble

Author

D. Grandi, Massimo Gervasi, Igor V. Moskalenko, N. Masi, Pier-Giorgio Rancoita, Lucio Quadrani, Davide Rozza, G. Jóhannesson, Mauro Tacconi, Matteo Boschini, S. Pensotti, T. A. Porter, S. Della Torre, G. La Vacca, Boschini, M, Della Torre, S, Gervasi, M, Grandi, D, Jóhannesson, G, La Vacca, G, Masi, N, Moskalenko, I, Pensotti, S, Porter, T, Quadrani, L, Rancoita, P, Rozza, D, and Tacconi, M

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, FOS: Physical sciences, Interplanetary medium, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Spectral line, Article, Galactic cosmic ray, Interstellar medium, Supernova, Heliosphere, FIS/05 - ASTRONOMIA E ASTROFISICA, Local Bubble, FIS/01 - FISICA SPERIMENTALE, Space and Planetary Science, Cosmic ray detector, Cosmic ray source, Ionization energy, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Since its launch, the Alpha Magnetic Spectrometer - 02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species, $\bar{p}$, $e^{\pm}$, and nuclei, $_1$H-$_8$O, $_{10}$Ne, $_{12}$Mg, $_{14}$Si, which resulted in a number of breakthroughs. One of the latest long awaited surprises is the spectrum of $_{26}$Fe just published by AMS-02. Because of the large fragmentation cross section and large ionization energy losses, most of CR iron at low energies is local, and may harbor some features associated with relatively recent supernova (SN) activity in the solar neighborhood. Our analysis of new iron spectrum together with Voyager 1 and ACE-CRIS data reveals an unexpected bump in the iron spectrum and in the Fe/He, Fe/O, and Fe/Si ratios at 1-2 GV, while a similar feature in the spectra of He, O, Si, and in their ratios is absent, hinting at a local source of low-energy CRs. The found excess fits well with recent discoveries of radioactive $^{60}$Fe deposits in terrestrial and lunar samples, and in CRs. We provide an updated local interstellar spectrum (LIS) of iron in the energy range from 1 MeV nucleon$^{-1}$ to $\sim$10 TeV nucleon$^{-1}$. Our calculations employ the GalProp-HelMod framework that is proved to be a reliable tool in deriving the LIS of CR $\bar{p}$, $e^{-}$, and nuclei $Z\le28$., 12 pages, 9 figures, 5 tables; Accepted for publication in the Astrophysical Journal. arXiv admin note: text overlap with arXiv:2006.01337

Published
2021

24. GALACTIC COSMIC RAYS IN THE LOCAL INTERSTELLAR MEDIUM

Author

A C, Cummings, E C, Stone, B C, Heikkila, N, Lal, W R, Webber, G, Jóhannesson, I V, Moskalenko, E, Orlando, and T A, Porter

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Experiment, Article
Abstract

Since 2012 August Voyager 1 has been observing the local interstellar energy spectra of Galactic cosmic-ray nuclei down to 3 MeV nuc(−1) and electrons down to 2.7 MeV. The H and He spectra have the same energy dependence between 3 and 346 MeV nuc(−1), with a broad maximum in the 10–50 MeV nuc(−1) range and a H/He ratio of 12.2 ± 0.9. The peak H intensity is ~15 times that observed at 1 AU, and the observed local interstellar gradient of 3–346 MeV H is −0.009 ± 0.055% AU(−1), consistent with models having no local interstellar gradient. The energy spectrum of electrons (e(−) + e(+)) with 2.7–74 MeV is consistent with E(−1.30±0.05) and exceeds the H intensity at energies below ~50 MeV. Propagation model fits to the observed spectra indicate that the energy density of cosmic-ray nuclei with >3 MeV nuc(−1) and electrons with >3 MeV is 0.83–1.02 eV cm(−3) and the ionization rate of atomic H is in the range of 1.51–1.64 × 10(−17) s(−1). This rate is a factor >10 lower than the ionization rate in diffuse interstellar clouds, suggesting significant spatial inhomogeneity in low-energy cosmic rays or the presence of a suprathermal tail on the energy spectrum at much lower energies. The propagation model fits also provide improved estimates of the elemental abundances in the source of Galactic cosmic rays.

Published
2021

25. Erratum: 'Inference of the Local Interstellar Spectra of Cosmic-Ray Nuclei Z ⩽ 28 with the GALPROP–HELMOD Framework' (2020, ApJS, 250, 27)

Author

N. Masi, Igor V. Moskalenko, Pier-Giorgio Rancoita, G. Jóhannesson, Matteo Boschini, Massimo Gervasi, D. Grandi, Lucio Quadrani, G. La Vacca, Mauro Tacconi, S. Pensotti, T. A. Porter, Davide Rozza, and S. Della Torre

Subjects
Physics, Space and Planetary Science, Inference, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Spectral line, Article
Abstract

Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of

Published
2021

26. Galactic PeVatrons and helping to find them: Effects of galactic absorption on the observed spectra of very high energy

Author

T A, Porter, G P, Rowell, G, Jóhannesson, and I V, Moskalenko

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics, Article
Abstract

Identification of the cosmic-ray (CR) “PeVatrons,” which are sources capable of accelerating particles to ~10(15) eV energies and higher, may lead to resolving the long-standing question of the origin of the spectral feature in the all-particle CR spectrum known as the “knee.” Because CRs with these energies are deflected by interstellar magnetic fields identification of individual sources and determination of their spectral characteristics is more likely via very high energy γ-ray emissions, which provide the necessary directional information. However, pair production on the interstellar radiation field (ISRF) and cosmic microwave background (CMB) leads to steepening of the high energy tails of γ-ray spectra, and should be corrected for to enable true properties of the spectrum at the source to be recovered. Employing recently developed three-dimensional ISRF models this paper quantifies the pair-absorption effect on spectra for sources in the Galactic center (GC) direction at 8.5 and 23.5 kpc distances, with the latter corresponding to the far side of the Galactic stellar disc where it is expected that discrimination of spectral features >10 TeV is possible by the forthcoming Cherenkov Telescope Array (CTA). The estimates made suggest spectral cutoffs could be underestimated by factors of a few in the energy range so far sampled by TeV γ-ray telescopes. As an example to illustrate this, the recent HESS measurements of diffuse γ-ray emissions possibly associated with injection of CRs nearby Sgr A* are ISRF corrected, and estimates of the spectral cutoff are reevaluated. It is found that it could be higher by up to a factor of ~2, indicating that these emissions may be consistent with a CR accelerator with a spectral cutoff of at least 1 PeV at the 95% confidence level.

Published
2021

27. Search for Spectral Irregularities due to Photon–Axionlike-Particle Oscillations with the Fermi Large Area Telescope

Author

M. Ajello, A. Albert, B. Anderson, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, R. Buehler, G. A. Caliandro, R. A. Cameron, M. Caragiulo, P. A. Caraveo, C. Cecchi, A. Chekhtman, S. Ciprini, J. Cohen-Tanugi, J. Conrad, F. Costanza, F. D’Ammando, A. de Angelis, F. de Palma, R. Desiante, M. Di Mauro, L. Di Venere, A. Domínguez, P. S. Drell, C. Favuzzi, W. B. Focke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, T. Glanzman, G. Godfrey, S. Guiriec, D. Horan, G. Jóhannesson, M. Katsuragawa, S. Kensei, M. Kuss, S. Larsson, L. Latronico, J. Li, L. Li, F. Longo, F. Loparco, P. Lubrano, G. M. Madejski, S. Maldera, A. Manfreda, M. Mayer, M. N. Mazziotta, M. Meyer, P. F. Michelson, N. Mirabal, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Negro, E. Nuss, C. Okada, E. Orlando, J. F. Ormes, D. Paneque, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, M. Sánchez-Conde, C. Sgrò, D. Simone, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, H. Takahashi, J. B. Thayer, D. F. Torres, G. Tosti, E. Troja, Y. Uchiyama, K. S. Wood, M. Wood, G. Zaharijas, and S. Zimmer

Published
2016
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28. Resolving the Extragalacticγ-Ray Background above 50 GeV with the Fermi Large Area Telescope

Author

M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, J. Bregeon, R. J. Britto, P. Bruel, R. Buehler, G. A. Caliandro, R. A. Cameron, M. Caragiulo, P. A. Caraveo, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, J. Cohen-Tanugi, L. R. Cominsky, F. Costanza, S. Cutini, F. D’Ammando, A. de Angelis, F. de Palma, R. Desiante, S. W. Digel, M. Di Mauro, L. Di Venere, A. Domínguez, P. S. Drell, C. Favuzzi, S. J. Fegan, E. C. Ferrara, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, G. Godfrey, D. Green, I. A. Grenier, S. Guiriec, E. Hays, D. Horan, G. Iafrate, T. Jogler, G. Jóhannesson, M. Kuss, G. La Mura, S. Larsson, L. Latronico, J. Li, L. Li, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, J. Magill, S. Maldera, A. Manfreda, M. Mayer, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Negro, E. Nuss, T. Ohsugi, C. Okada, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. S. Perkins, M. Pesce-Rollins, V. Petrosian, F. Piron, G. Pivato, T. A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, R. W. Romani, M. Sánchez-Conde, J. Schmid, A. Schulz, C. Sgrò, D. Simone, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, D. J. Suson, H. Takahashi, J. B. Thayer, L. Tibaldo, D. F. Torres, E. Troja, G. Vianello, M. Yassine, and S. Zimmer

Published
2016
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29. Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope

Author

M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, R. Buehler, G. A. Caliandro, R. A. Cameron, M. Caragiulo, P. A. Caraveo, E. Cavazzuti, C. Cecchi, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, F. Costanza, A. Cuoco, S. Cutini, F. D’Ammando, A. de Angelis, F. de Palma, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, C. Favuzzi, S. J. Fegan, W. B. Focke, A. Franckowiak, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, A. K. Harding, J. W. Hewitt, D. Horan, X. Hou, G. Iafrate, G. Jóhannesson, T. Kamae, M. Kuss, S. Larsson, L. Latronico, J. Li, L. Li, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, J. Magill, S. Maldera, A. Manfreda, M. Mayer, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, M. E. Monzani, A. Morselli, S. Murgia, E. Nuss, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. S. Perkins, M. Pesce-Rollins, V. Petrosian, F. Piron, G. Pivato, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, C. Sgrò, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, H. Takahashi, J. B. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, E. Troja, G. Vianello, B. L. Winer, K. S. Wood, M. Yassine, F. Cerutti, A. Ferrari, and P. R. Sala

Published
2016
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30. Localisation and classification of gamma ray sources using neural networks

Author

Boris Panes, G. Jóhannesson, Roberto Ruiz de Austri, Saptashwa Bhattacharyya, Gabrijela Zaharijas, Chris van den Oetelaar, and Sascha Caron

Subjects
Artificial neural network, Point source, Computer science, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Deep learning, Detector, Pattern recognition, Image segmentation, Experimental High Energy Physics, High Energy Physics, Artificial intelligence, Cluster analysis, business, Image resolution, Energy (signal processing)
Abstract

With limited statistics and spatial resolution of current detectors, accurately localising and separating gamma-ray point sources from the dominating interstellar emission in the GeV energy range is challenging. Motivated by the challenges of the traditional methods used for the gamma-ray source detection, here we demonstrate the application of deep learning based algorithms to automatically detect and classify point sources, which can be applied directly to the binned Fermi-LAT data and potentially be generalised to other wavelengths. For the point source detection task, we use popular deep neural network structure U-NET, together with image segmentation, for precise localisation of sources, various clustering algorithms were tested on the segmented images. The training samples are based on the source properties of AGNs and PSRs from the latest Fermi-LAT source catalog, in addition to the background interstellar emission. Finally, we have created a more complex but robust training data generation exploiting full detector potential, increasing spatial resolution at the highest energies.

Published
2021

31. Fermi Large Area Telescope Performance After 10 Years Of Operation

Author

Soebur Razzaque, R. Buehler, T. A. Porter, J. Li, Peter F. Michelson, Marcello Giroletti, L. Tibaldo, F. Piron, Denis Bastieri, N. Saggini, N. Di Lalla, G. Tosti, Dario Gasparrini, Francesco Longo, A. Fiori, Stefan Larsson, J. G. Thayer, Ioannis Liodakis, F. Fana Dirirsa, W. B. Atwood, Luca Baldini, J. S. Perkins, M. Ceccanti, Alessandro Brez, D. Serini, Sylvain Guiriec, Stefano Ciprini, Mn Mazziotta, S. Rainò, Tsunefumi Mizuno, G. Foglia, M. Razzano, Johann Cohen-Tanugi, J. Bregeon, Sina Chen, L. Di Venere, Michele Pinchera, T. J. Johnson, Seth Digel, Elliott D. Bloom, F. Loparco, M. N. Lovellette, M.-H. Grondin, F. Gargano, Hiroyasu Tajima, R. Primavera, Ronaldo Bellazzini, J. E. Grove, Yasushi Fukazawa, E. Orlando, M. Lemoine-Goumard, Marco Ajello, E. Rapposelli, Roopesh Ojha, Denise A. Smith, E. Hays, P. M. Saz Parkinson, E. J. Siskind, G. Principe, Manuel Meyer, P. Fusco, N. Menon, Diego F. Torres, Melissa Pesce-Rollins, J. Valverde, Matthew Kerr, Elisabetta Bissaldi, H. Poon, M. Orienti, S. Buson, Vaidehi S. Paliya, D. J. Thompson, D. Fabiani, Carmelo Sgrò, Riccardo Rando, Magnus Axelsson, A. Reimer, Massimo Minuti, S. Maldera, J. J. Russell, Warit Mitthumsiri, R. Bagagli, S. Griffin, F. D'Ammando, T. Kamae, G. Martí-Devesa, Z. Pei, E. Cavazzuti, E. Nuss, David Paneque, P. Spinelli, T. Glanzman, M. Bagni, F. de Palma, Alessandro Paccagnella, M. Kuss, Aaron Dominguez, M. Mongelli, Luca Latronico, Igor V. Moskalenko, Gloria Spandre, N. Scolieri, R. A. Cameron, G. Jóhannesson, Gabrijela Zaharijas, Alberto Manfreda, L. Vigiani, Bindu Rani, P. Bruel, Ismaël Cognard, Olaf Reimer, D. Horan, P. de la Torre Luque, L. Guillemot, M. E. Monzani, F. Bellardi, Elizabeth C. Ferrara, David A. Green, I. Mereu, P. Caraveo, S. Cutini, D. J. Suson, C. C. Cheung, R. Bonino, P. Lubrano, M. Gustafsson, J. L. Racusin, M. Negro, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ajello, M., Atwood, W. B., Axelsson, M., Bagagli, R., Bagni, M., Baldini, L., Bastieri, D., Bellardi, F., Bellazzini, R., Bissaldi, E., Bloom, E. D., Bonino, R., Bregeon, J., Brez, A., Bruel, P., Buehler, R., Buson, S., Cameron, R. A., Caraveo, P. A., Cavazzuti, E., Ceccanti, M., Chen, S., Cheung, C. C., Ciprini, S., Cognard, I., Cohen-Tanugi, J., Cutini, S., D???ammando, F., de la Torre Luque, P., de Palma, F., Digel, S. W., Dirirsa, F., Di Lalla, N., Di Venere, L., Dom??nguez, A., Fabiani, D., Ferrara, E. C., Fiori, A., Foglia, G., Fukazawa, Y., Fusco, P., Gargano, F., Gasparrini, D., Giroletti, M., Glanzman, T., Green, D., Griffin, S., Grondin, M. -H., Grove, J. E., Guillemot, L., Guiriec, S., Gustafsson, M., Hays, E., Horan, D., J??hannesson, G., Johnson, T. J., Kamae, T., Kerr, M., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Liodakis, I., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Mart??-Devesa, G., Mazziotta, M. N., Menon, N., Mereu, I., Meyer, M., Michelson, P. F., Minuti, M., Mitthumsiri, W., Mizuno, T., Mongelli, M., Monzani, M. E., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Orienti, M., Orlando, E., Paccagnella, A., Paliya, V. S., Paneque, D., Pei, Z., Perkins, J. S., Pesce-Rollins, M., Pinchera, M., Piron, F., Poon, H., Porter, T. A., Primavera, R., Principe, G., Racusin, J. L., Rain??, S., Rando, R., Rani, B., Rapposelli, E., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Russell, J. J., Saggini, N., Saz Parkinson, P. M., Scolieri, N., Serini, D., Sgr??, C., Siskind, E. J., Smith, D. A., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. G., Thompson, D. J., Tibaldo, L., Torres, D. F., Tosti, G., Valverde, J., Vigiani, L., and Zaharijas, G.

Subjects
Calibration (statistics), Gamma-ray telescopes, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, 030226 pharmacology & pharmacy, 01 natural sciences, 7. Clean energy, law.invention, Telescope, 03 medical and health sciences, 0302 clinical medicine, law, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Condensed Matter::Quantum Gases, Physics, Gamma-ray astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Calibration, Condensed Matter::Strongly Correlated Electrons, Astrophysics - Instrumentation and Methods for Astrophysics, Fermi Gamma-ray Space Telescope
Abstract

The Large Area Telescope (LAT), the primary instrument for the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from 30 MeV to more than 300 GeV. We describe the performance of the instrument at the 10-year milestone. LAT performance remains well within the specifications defined during the planning phase, validating the design choices and supporting the compelling case to extend the duration of the Fermi mission. The details provided here will be useful when designing the next generation of high-energy gamma-ray observatories., 60 pages, 28 figures. Published in ApJS

Published
2021

32. Searching for Dark Matter Annihilation from Milky Way Dwarf Spheroidal Galaxies with Six Years of Fermi Large Area Telescope Data

Author

M. Ackermann, A. Albert, B. Anderson, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, G. A. Caliandro, R. A. Cameron, R. Caputo, M. Caragiulo, P. A. Caraveo, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. Cuoco, S. Cutini, F. D’Ammando, A. de Angelis, F. de Palma, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, A. Drlica-Wagner, R. Essig, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, S. Guiriec, M. Gustafsson, E. Hays, J. W. Hewitt, D. Horan, T. Jogler, G. Jóhannesson, M. Kuss, S. Larsson, L. Latronico, J. Li, L. Li, M. Llena Garde, F. Longo, F. Loparco, P. Lubrano, D. Malyshev, M. Mayer, M. N. Mazziotta, J. E. McEnery, M. Meyer, P. F. Michelson, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, S. Murgia, E. Nuss, T. Ohsugi, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, M. Sánchez-Conde, A. Schulz, N. Sehgal, C. Sgrò, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, L. Strigari, H. Tajima, H. Takahashi, J. B. Thayer, L. Tibaldo, D. F. Torres, E. Troja, G. Vianello, M. Werner, B. L. Winer, K. S. Wood, M. Wood, G. Zaharijas, and S. Zimmer

Published
2015
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33. Updated search for spectral lines from Galactic dark matter interactions with pass 8 data from the Fermi Large Area Telescope

Author

M. Ackermann, M. Ajello, A. Albert, B. Anderson, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, R. Caputo, M. Caragiulo, P. A. Caraveo, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. Cuoco, S. Cutini, F. D’Ammando, A. de Angelis, F. de Palma, R. Desiante, S. W. Digel, L. Di Venere, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, S. J. Fegan, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, G. Godfrey, G. A. Gomez-Vargas, I. A. Grenier, J. E. Grove, S. Guiriec, M. Gustafsson, J. W. Hewitt, A. B. Hill, D. Horan, G. Jóhannesson, R. P. Johnson, M. Kuss, S. Larsson, L. Latronico, J. Li, L. Li, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, D. Malyshev, M. Mayer, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, S. Murgia, E. Nuss, T. Ohsugi, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, M. Pesce-Rollins, F. Piron, G. Pivato, S. Rainò, R. Rando, M. Razzano, A. Reimer, T. Reposeur, S. Ritz, M. Sánchez-Conde, A. Schulz, C. Sgrò, E. J. Siskind, F. Spada, G. Spandre, P. Spinelli, H. Tajima, H. Takahashi, J. B. Thayer, L. Tibaldo, D. F. Torres, G. Tosti, E. Troja, G. Vianello, M. Werner, B. L. Winer, K. S. Wood, M. Wood, G. Zaharijas, and S. Zimmer

Published
2015
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34. First fermi-LAT solar flare catalog

Author

Sara Buson, F. D'Ammando, T. A. Porter, L. Di Venere, S. Rainò, F. Piron, Yasushi Fukazawa, J. W. Hewitt, J. Li, Luca Baldini, E. J. Siskind, Marcello Giroletti, S. Maldera, D. Gasparrini, P. Lubrano, P. Fusco, Sylvain Guiriec, F. Fana Dirirsa, Seb. Funk, E. Cavazzuti, Gloria Spandre, Nicola Omodei, Mn Mazziotta, P. F. Michelson, S. J. Fegan, Soebur Razzaque, E. Hays, Ferdinando Giordano, M. N. Lovellette, D. Costantin, Carmelo Sgrò, F. Longo, Marco Ajello, K. S. Wood, F. de Palma, E. Troja, T. Mizuno, Regina Caputo, G. Zaharijas, F. Gargano, David Paneque, N. Di Lalla, Elisabetta Bissaldi, D. Green, R. Rando, C. C. Cheung, J. Valverde, Bindu Rani, M. Kuss, Luca Latronico, D. Tak, D. Bastieri, R. Bonino, G. Jóhannesson, E. Orlando, M. Negro, A. Berretta, A. Reimer, Z. Pei, G. Chiaro, P. Spinelli, M. E. Monzani, Melissa Pesce-Rollins, Vahé Petrosian, Giacomo Principe, D. Serini, Alberto Manfreda, S. Larsson, Massimo Persic, M. Orienti, M. Razzano, Miloš Kovačević, A. Morselli, R. A. Cameron, G. Martí-Devesa, P. Bruel, S. Cutini, R. Desiante, J. L. Racusin, I. Mereu, Roger Blandford, Igor V. Moskalenko, Olaf Reimer, D. Horan, R. Bellazzini, Ajello, M., Baldini, L., Bastieri, D., Bellazzini, R., Berretta, A., Bissaldi, E., Blandford, R. D., Bonino, R., Bruel, P., Buson, S., Cameron, R. A., Caputo, R., Cavazzuti, E., Cheung, C. C., Chiaro, G., Costantin, D., Cutini, S., D'Ammando, F., De Palma, F., Desiante, R., Di Lalla, N., Di Venere, L., Fana Dirirsa, F., Fegan, S. J., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giordano, F., Giroletti, M., Green, D., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Johannesson, G., Kovac'Evic, M., Kuss, M., Larsson, S., Latronico, L., Li, J., Longo, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Marti-Devesa, G., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Omodei, N., Orienti, M., Orlando, E., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Racusin, J. L., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Serini, D., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Tak, D., Troja, E., Valverde, J., Wood, K., Zaharijas, G., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), D???ammando, F., de Palma, F., J??hannesson, G., Kovac???evic???, M., Mart??-Devesa, G., Rain??, S., and Sgr??, C.

Subjects
Solar gamma-ray emission, Gamma-ray telescopes, Astrophysics::High Energy Astrophysical Phenomena, Population, Astrophysics, Solar flares, Gamma-ray sources, Catalogs, 01 natural sciences, law.invention, Telescope, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, education, 010303 astronomy & astrophysics, Physics, education.field_of_study, Solar flare, Astronomy and Astrophysics, Solar flares, Solar gamma-ray emission, Gamma-ray sources, Gamma-ray telescopes, Catalogs, Solar physics, Light curve, Solar cycle, Gamma-ray source, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Gamma-ray telescope, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope, Flare
Abstract

We present the first Fermi - Large Area Telescope (LAT) solar flare catalog covering the 24 th solar cycle. This catalog contains 45 Fermi -LAT solar flares (FLSFs) with emission in the gamma-ray energy band (30 MeV - 10 GeV) detected with a significance greater than 5 sigma over the years 2010-2018. A subsample containing 37 of these flares exhibit delayed emission beyond the prompt-impulsive hard X-ray phase with 21 flares showing delayed emission lasting more than two hours. No prompt-impulsive emission is detected in four of these flares. We also present in this catalog the observations of GeV emission from 3 flares originating from Active Regions located behind the limb (BTL) of the visible solar disk. We report the light curves, spectra, best proton index and localization (when possible) for all the FLSFs. The gamma-ray spectra is consistent with the decay of pions produced by >300 MeV protons. This work contains the largest sample of high-energy gamma-ray flares ever reported and provides the unique opportunity to perform population studies on the different phases of the flare and thus allowing to open a new window in solar physics.

Published
2021

35. Gamma Rays from Fast Black-hole Winds

Author

M. Razzano, Francesco Longo, J. Zrake, S. Buson, Junyao Li, A. Franckowiak, Elisabetta Bissaldi, Diego F. Torres, N. Di Lalla, Luca Baldini, Aaron Dominguez, M. E. Monzani, Sylvain Guiriec, Mn Mazziotta, C. Karwin, Alberto Manfreda, Bindu Rani, Denis Bastieri, Nicola Omodei, F. D'Ammando, G. Jóhannesson, P. M. Saz Parkinson, A. Desai, S. Marchesi, D. Costantin, Peter F. Michelson, Marcello Giroletti, M. Orienti, Marco Ajello, Damiano Caprioli, A. Berretta, Sina Chen, A. Reimer, Igor V. Moskalenko, Olaf Reimer, Carmelo Sgrò, Riccardo Rando, Miloš Kovačević, Z. Pei, A. Morselli, Melissa Pesce-Rollins, Rebecca Diesing, Stefan Larsson, J. L. Racusin, David Paneque, G. Chiaro, M. Kuss, Vaidehi S. Paliya, P. Spinelli, L. Marcotulli, T. A. Porter, G. Principe, S. Maldera, P. Fusco, G. Martí-Devesa, F. de Palma, Francesco Giordano, M. Negro, Dario Gasparrini, J. Ballet, Roger Blandford, I. Mereu, F. Loparco, Matthew Kerr, E. Orlando, S. J. Fegan, Dieter H. Hartmann, S. Cutini, David A. Green, Stefan Funk, D. Horan, George Chartas, Massimo Persic, Regina Caputo, Ronaldo Bellazzini, D. Serini, R. A. Cameron, Nicola Giglietto, P. Lubrano, I. A. Grenier, Guido Barbiellini, P. Bruel, D. Tak, M. N. Lovellette, Ioannis Liodakis, S. Rainò, Tsunefumi Mizuno, Yasushi Fukazawa, Gabrijela Zaharijas, K. S. Wood, E. Troja, Elliott D. Bloom, R. Bonino, E. J. Siskind, D. J. Suson, Luca Latronico, C. C. Cheung, P. de la Torre Luque, F. Gargano, E. Cavazzuti, Gloria Spandre, F. Dirirsa, L. Di Venere, M. Lemoine-Goumard, National Aeronautics and Space Administration (US), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Berretta, A., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bonino, R., Bruel, P., Buson, S., Cameron, R. A., Caprioli, D., Caputo, R., Cavazzuti, E., Chartas, G., Chen, S., Cheung, C. C., Chiaro, G., Costantin, D., Cutini, S., D'Ammando, F., De La Torre Luque, P., De Palma, F., Desai, A., Diesing, R., Di Lalla, N., Dirirsa, F., Di Venere, L., Dominguez, A., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guiriec, S., Hartmann, D., Horan, D., Johannesson, G., Karwin, C., Kerr, M., Kovacevic, M., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Liodakis, I., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Marchesi, S., Marcotulli, L., Marti-Devesa, G., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Omodei, N., Orienti, M., Orlando, E., Paliya, V., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Porter, T. A., Principe, G., Racusin, J. L., Rain, S., Rando, R., Rani, B., Razzano, M., Reimer, A., Reimer, O., Saz Parkinson, P. M., Serini, D., Sgr, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tak, D., Torres, D. F., Troja, E., Wood, K., Zaharijas, G., Zrake, J., Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), D???ammando, F., de la Torre Luque, P., de Palma, F., Dom??nguez, A., J??hannesson, G., Kova??evi??, M., Mart??-Devesa, G., Rain??, S., and Sgr??, C.

Subjects
Physics, Active galactic nuclei, Black hole, Black holes, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxies, Astrophysics - Astrophysics of Galaxies, Galaxie, Space and Planetary Science, Galactic winds, Galactic Winds, Astrophysics::Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Gamma-rays, Astrophysics::Galaxy Astrophysics
Abstract

Massive black holes at the centers of galaxies can launch powerful wide-angle winds that, if sustained over time, can unbind the gas from the stellar bulges of galaxies. These winds may be responsible for the observed scaling relation between the masses of the central black holes and the velocity dispersion of stars in galactic bulges. Propagating through the galaxy, the wind should interact with the interstellar medium creating a strong shock, similar to those observed in supernovae explosions, which is able to accelerate charged particles to high energies. In this work we use data from the Fermi Large Area Telescope to search for the γ-ray emission from galaxies with an ultrafast outflow (UFO): a fast (v ∼ 0.1 c), highly ionized outflow, detected in absorption at hard X-rays in several nearby active galactic nuclei (AGN). Adopting a sensitive stacking analysis we are able to detect the average γ-ray emission from these galaxies and exclude that it is due to processes other than UFOs. Moreover, our analysis shows that the γ-ray luminosity scales with the AGN bolometric luminosity and that these outflows transfer ∼0.04% of their mechanical power to γ-rays. Interpreting the observed γ-ray emission as produced by cosmic rays (CRs) accelerated at the shock front, we find that the γ-ray emission may attest to the onset of the wind-host interaction and that these outflows can energize charged particles up to the transition region between galactic and extragalactic CRs., Ajello, M., et al., M.A. and C.K. acknowledge support from NSF and NASA through grants AST-1715256, 80NSSC21K1915, and 80NSSC18K1718. R.D. and D.C. acknowledge the Eugene & Niesje Parker Fellowship Fund, NASA (grants NNX17AG30G, 80NSSC18K1218, and 80NSSC18K1726) and the NSF (grants AST-1714658, AST-1909778). G.C. acknowledges financial support from NASA grants 80NSSC20K0438 and 80NSSC19K095.

Published
2021

36. Inference of the local interstellar spectra of cosmic-ray nuclei Z ≼ 28 with the GALPROP-HELMOD Framework

Author

Mauro Tacconi, Massimo Gervasi, Troy A. Porter, G. Jóhannesson, G. La Vacca, S. Della Torre, N. Masi, L. Quadrani, Igor V. Moskalenko, Pier-Giorgio Rancoita, D. Grandi, S. Pensotti, D. Rozza, Matteo Boschini, Boschini M.J., della Torre S., Gervasi M., Grandi D., Johannesson G., la Vacca G., Masi N., Moskalenko I.V., Pensotti S., Porter T.A., Quadrani L., Rancoita P.G., Rozza D., Tacconi M., Boschini, M, Torre, S, Gervasi, M, Grandi, D, Jóhannesson, G, La Vacca, G, Masi, N, Moskalenko, I, Pensotti, S, Porter, T, Quadrani, L, Rancoita, P, Rozza, D, and Tacconi, M

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Interplanetary medium, Cosmic ray, Astrophysics, 01 natural sciences, Article, Galactic cosmic ray, FIS/05 - ASTRONOMIA E ASTROFISICA, Heliosphere, Cosmic ray detectors, Interstellar medium, 0103 physical sciences, Cosmic ray source, 010306 general physics, 010303 astronomy & astrophysics, Physics, Astronomy and Astrophysics, Abundance of the chemical elements, FIS/01 - FISICA SPERIMENTALE, Orders of magnitude (time), Space and Planetary Science, Antiproton, Antimatter, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of gamma-ray and microwave observations, disentangling possible signatures of new phenomena, and for understanding of our local Galactic neighborhood. Since its launch, AMS-02 has delivered outstanding quality measurements of the spectra of antiprotons, electrons, positrons, and nuclei: H-O, Ne, Mg, Si. These measurements resulted in a number of breakthroughs, however, spectra of heavier nuclei and especially low-abundance nuclei are not expected until later in the mission. Meanwhile, a comparison of published AMS-02 results with earlier data from HEAO-3-C2 indicate that HEAO-3-C2 data may be affected by undocumented systematic errors. Utilizing such data to compensate for the lack of AMS-02 measurements could result in significant errors. In this paper we show that a fraction of HEAO-3-C2 data match available AMS-02 measurements quite well and can be used together with Voyager 1 and ACE-CRIS data to make predictions for the local interstellar spectra (LIS) of nuclei that are not yet released by AMS-02. We are also updating our already published LIS to provide a complete set from H-Ni in the energy range from 1 MeV/nucleon to ~100-500 TeV/nucleon thus covering 8-9 orders of magnitude in energy. Our calculations employ the GalProp-HelMod framework that is proved to be a reliable tool in deriving the LIS of CR antiprotons, electrons, and nuclei H-O., Comment: 90 pages, 36 figures, 60 tables, ApJS; Fixed typos in Eqs.(C2) and (C32)

Published
2020

37. The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope

Author

Michael Kreter, Carmelo Sgrò, Riccardo Rando, Leonid Petrov, E. Nuss, M. Kuss, Nicola Omodei, M. Orienti, Diego F. Torres, M. Yassine, E. Hays, Francesco Massaro, G. Jóhannesson, L. S. Ojha, S. Harita, Frank K. Schinzel, Marco Ajello, E. Orlando, S. Maldera, B. Lott, R. Itoh, Jean Ballet, S. Garrappa, G. Martí-Devesa, F. Piron, G. M. Madejski, Francesco Longo, Manuel Meyer, Eleonora Torresi, R. Bonino, Giacomo Principe, Stefano Ciprini, J. Li, E. Troja, Marcello Giroletti, Nestor Mirabal, A. Reimer, Stefan Funk, P. van Zyl, Melissa Pesce-Rollins, Eugenio Bottacini, J. F. Ormes, P. Fusco, F. Gargano, Elliott D. Bloom, C. Leto, F. Fana Dirirsa, N. Di Lalla, C. C. Cheung, J. Valverde, Stefan Larsson, Sylvain Guiriec, Alberto Manfreda, Denis Bastieri, Z. Pei, A. Morselli, Igor V. Moskalenko, Soebur Razzaque, P. de la Torre Luque, Mn Mazziotta, Elizabeth C. Ferrara, Olaf Reimer, Justin D. Finke, I. A. Grenier, M. Razzano, F. de Palma, Filippo D'Ammando, D. J. Suson, D. Costantin, Nicola Giglietto, Yutaro Tachibana, Vaidehi S. Paliya, F. Loparco, R. Angioni, E. Cavazzuti, M. N. Lovellette, P. Lubrano, J. Becerra González, H. Poon, Gloria Spandre, E. J. Siskind, Giulia Migliori, Aaron Dominguez, Elisabetta Bissaldi, R. A. Cameron, David A. Green, Rodrigo Nemmen, D. J. Thompson, D. Horan, P. Bruel, Magnus Axelsson, R. de Menezes, Anna Franckowiak, S. Buson, Ioannis Liodakis, S. Rainò, Tsunefumi Mizuno, Yasushi Fukazawa, P. Spinelli, Ronaldo Bellazzini, Francesco Giordano, Fabio Cafardo, Bindu Rani, Dario Gasparrini, Felicia Krauss, Abhishek Desai, Sina Chen, L. Di Venere, Roopesh Ojha, H. A. Peña-Herazo, Massimo Persic, D. Serini, Guido Barbiellini, I. Mereu, S. Cutini, M. E. Monzani, M. Negro, Miloš Kovačević, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, National Aeronautics and Space Administration (US), Department of Energy (US), Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Centre National de la Recherche Scientifique (France), Institut National de Physique Nucléaire et de Physique des Particules (France), Agenzia Spaziale Italiana, Istituto Nazionale di Fisica Nucleare, Ministry of Education, Culture, Sports, Science and Technology (Japan), High Energy Accelerator Research Organization (Japan), Japan Aerospace Exploration Agency, Knut and Alice Wallenberg Foundation, Swedish Research Council, Swedish National Space Board, Istituto Nazionale di Astrofisica, Ajello, M., Angioni, R., Axelsson, M., Ballet, J., Barbiellini, G., Bastieri, D., Becerra Gonzalez, J., Bellazzini, R., Bissaldi, E., Bloom, E. D., Bonino, R., Bottacini, E., Bruel, P., Buson, S., Cafardo, F., Cameron, R. A., Cavazzuti, E., Chen, S., Cheung, C. C., Ciprini, S., Costantin, D., Cutini, S., D'Ammando, F., De La Torre Luque, P., De Menezes, R., De Palma, F., Desai, A., Di Lalla, N., Di Venere, L., Dominguez, A., Dirirsa, F. F., Ferrara, E. C., Finke, J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Garrappa, S., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guiriec, S., Harita, S., Hays, E., Horan, D., Itoh, R., Johannesson, G., Kovac'Evic', M., Krauss, F., Kreter, M., Kuss, M., Larsson, S., Leto, C., Li, J., Liodakis, I., Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Maldera, S., Manfreda, A., Marti-Devesa, G., Massaro, F., Mazziotta, M. N., Mereu, I., Meyer, M., Migliori, G., Mirabal, N., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nemmen, R., Nuss, E., Ojha, L. S., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Paliya, V. S., Pei, Z., Peña-Herazo, H., Persic, M., Pesce-Rollins, M., Petrov, L., Piron, F., Poon, H., Principe, G., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Schinzel, F. K., Serini, D., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tachibana, Y., Thompson, D. J., Torres, D. F., Torresi, E., Troja, E., Valverde, J., Van Zyl, P., Yassine, M., Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), and 33379009 - Kreter, Michael

Subjects
galaxies [Gamma rays], Astrophysics, Blazar, 01 natural sciences, law.invention, observations [Gamma rays], Spitzer Space Telescope, Astrophysical jet, law, Relativistic jet, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Quasar, Physics, education.field_of_study, Galaxies: active, Quasars: general, Gamma rays: galaxies, Gamma-ray source, BL Lacertae objects, Astrophysics - High Energy Astrophysical Phenomena, Active galactic nucleus, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Population, BL Lacertae objetcs: general, Astrophysics::Cosmology and Extragalactic Astrophysics, Gamma rays: observations, Telescope, 0103 physical sciences, Active galactic nuclei, Blazars, Gamma-ray sources, Relativistic jets, Quasars, education, Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, general [Quasars], Astronomy and Astrophysics, general [BL Lacertae objetcs], [SDU]Sciences of the Universe [physics], Galaxies: jets, Space and Planetary Science, jets [Galaxies], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope
Abstract

The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains 2863 objects located at high Galactic latitudes (|b| > 10°). It includes 85% more sources than the previous 3LAC catalog based on 4 yr of data. AGNs represent at least 79% of the high-latitude sources in the fourth Fermi-Large Area Telescope Source Catalog (4FGL), which covers the energy range from 50 MeV to 1 TeV. In addition, 344 gamma-ray AGNs are found at low Galactic latitudes. Most of the 4LAC AGNs are blazars (98%), while the remainder are other types of AGNs. The blazar population consists of 24% Flat Spectrum Radio Quasars (FSRQs), 38% BL Lac-type objects, and 38% blazar candidates of unknown types (BCUs). On average, FSRQs display softer spectra and stronger variability in the gamma-ray band than BLQLacs do, confirming previous findings. All AGNs detected by ground-based atmospheric Cerenkov telescopes are also found in the 4LAC., The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat `a l’Energie Atomique and the Centre National de la Recherche Scientifique / Institut National de Physique Nucl´eaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Etudes Spatiales in France. This work performed in part under DOE Contract DE- AC02-76SF00515. This research has made use of data obtained from the high-energy Astrophysics Science Archive Research Center (HEASARC) provided by NASA’s Goddard Space Flight Center; the SIMBAD database operated at CDS, Strasbourg, France; the NASA/IPAC Extragalactic Database (NED) operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research has made use of data archives, catalogs and software tools from the ASDC, a facility managed by the Italian Space Agency (ASI). Part of this work is based on the NVSS (NRAO VLA Sky Survey). The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under contract with the National Science Foundation. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.

Published
2020

38. Erratum: First Fermi-LAT Solar Flare Catalog (2021, ApJS, 252, 13)

Author

E. Hays, G. Jóhannesson, M. Orienti, G. Zaharijas, G. Martí-Devesa, S. Larsson, Massimo Persic, Carmelo Sgrò, Luca Latronico, M. N. Lovellette, E. Troja, E. Orlando, David Paneque, S. Rainò, M. Kuss, Vahé Petrosian, R. Desiante, F. D'Ammando, Giacomo Principe, M. Negro, Miloš Kovačević, D. Green, Sara Buson, J. W. Hewitt, Yasushi Fukazawa, P. Spinelli, Seb. Funk, F. de Palma, J. Li, D. Bastieri, Marcello Giroletti, T. A. Porter, Regina Caputo, A. Morselli, S. Maldera, Luca Baldini, R. A. Cameron, E. Cavazzuti, Nicola Omodei, M. E. Monzani, D. Serini, T. Mizuno, P. Bruel, Gloria Spandre, Marco Ajello, R. Bonino, D. Tak, P. Fusco, Z. Pei, S. Cutini, Sylvain Guiriec, Igor V. Moskalenko, N. Di Lalla, Olaf Reimer, D. Horan, R. Bellazzini, F. Piron, R. Rando, Mn Mazziotta, P. F. Michelson, L. Di Venere, G. Chiaro, D. Gasparrini, C. C. Cheung, P. Lubrano, S. J. Fegan, J. L. Racusin, Ferdinando Giordano, D. Costantin, Soebur Razzaque, J. Valverde, Elisabetta Bissaldi, I. Mereu, Roger Blandford, A. Berretta, A. Reimer, F. Longo, Alberto Manfreda, M. Razzano, F. Gargano, Melissa Pesce-Rollins, E. J. Siskind, F. Fana Dirirsa, Bindu Rani, and K. S. Wood

Subjects
Physics, Solar flare, Space and Planetary Science, Astronomy and Astrophysics, Astrophysics, Fermi Gamma-ray Space Telescope
Published
2021

39. Anisotropies in the diffuse gamma-ray background measured by the Fermi LAT

Author

M. Ackermann, M. Ajello, A. Albert, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. D. Bloom, E. Bonamente, A. W. Borgland, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. Cuoco, S. Cutini, F. D’Ammando, F. de Palma, C. D. Dermer, S. W. Digel, E. do Couto e Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, C. Favuzzi, S. J. Fegan, E. C. Ferrara, P. Fortin, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, M. Giroletti, T. Glanzman, G. Godfrey, G. A. Gomez-Vargas, T. Grégoire, I. A. Grenier, J. E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, K. Hayashi, X. Hou, R. E. Hughes, G. Jóhannesson, A. S. Johnson, T. Kamae, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, T. Linden, A. M. Lionetto, M. Llena Garde, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, M. N. Mazziotta, J. E. McEnery, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pavlidou, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, S. Rainò, R. Rando, A. Reimer, O. Reimer, M. Roth, C. Sbarra, J. Schmitt, C. Sgrò, J. Siegal-Gaskins, E. J. Siskind, G. Spandre, P. Spinelli, A. W. Strong, D. J. Suson, H. Takahashi, T. Tanaka, J. B. Thayer, L. Tibaldo, M. Tinivella, D. F. Torres, G. Tosti, E. Troja, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, M. Wood, Z. Yang, S. Zimmer, and E. Komatsu

Published
2012
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40. Measurement of Separate Cosmic-Ray Electron and Positron Spectra with the Fermi Large Area Telescope

Author

M. Ackermann, M. Ajello, A. Allafort, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. de Angelis, F. de Palma, C. D. Dermer, S. W. Digel, E. do Couto e Silva, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, M. Gustafsson, D. Hadasch, A. K. Harding, M. Hayashida, R. E. Hughes, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, G. M. Madejski, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T. A. Porter, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, R. W. Romani, M. Roth, H. F.-W. Sadrozinski, C. Sbarra, T. L. Schalk, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, A. W. Strong, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, L. Tibaldo, M. Tinivella, D. F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, M. Wood, Z. Yang, and S. Zimmer

Published
2012
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41. Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope

Author

M. Ackermann, M. Ajello, A. Albert, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, B. Cañadas, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. de Angelis, F. de Palma, C. D. Dermer, S. W. Digel, E. do Couto e Silva, P. S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, S. J. Fegan, E. C. Ferrara, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, M. Hayashida, E. Hays, R. E. Hughes, T. E. Jeltema, G. Jóhannesson, R. P. Johnson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, A. M. Lionetto, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T. A. Porter, S. Profumo, S. Rainò, M. Razzano, A. Reimer, O. Reimer, S. Ritz, M. Roth, H. F.-W. Sadrozinski, C. Sbarra, J. D. Scargle, T. L. Schalk, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, L. Strigari, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, D. J. Thompson, L. Tibaldo, M. Tinivella, D. F. Torres, E. Troja, Y. Uchiyama, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, M. Wood, Z. Yang, S. Zimmer, M. Kaplinghat, and G. D. Martinez

Published
2011
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42. Constraints on dark matter models from a Fermi LAT search for high-energy cosmic-ray electrons from the Sun

Author

M. Ajello, W. B. Atwood, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, A. Bouvier, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, C. Cecchi, E. Charles, A. Chekhtman, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Cutini, A. de Angelis, F. de Palma, C. D. Dermer, S. W. Digel, E. do Couto e Silva, P. S. Drell, C. Favuzzi, S. J. Fegan, W. B. Focke, Y. Fukazawa, P. Fusco, F. Gargano, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, M. Gustafsson, D. Hadasch, G. Iafrate, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kuss, L. Latronico, A. M. Lionetto, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, M. Pesce-Rollins, M. Pierbattista, F. Piron, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, T. L. Schalk, C. Sgrò, J. Siegal-Gaskins, E. J. Siskind, P. D. Smith, G. Spandre, P. Spinelli, D. J. Suson, H. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, L. Tibaldo, G. Tosti, E. Troja, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, Z. Yang, and S. Zimmer

Published
2011
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43. Bright Gamma-Ray Flares Observed in GRB 131108A

Author

M. Ajello, M. Arimoto, K. Asano, M. Axelsson, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, R. Buehler, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, E. Cavazzuti, S. Chen, G. Chiaro, S. Ciprini, D. Costantin, S. Cutini, F. D’Ammando, P. de la Torre Luque, F. de Palma, N. Di Lalla, L. Di Venere, F. Fana Dirirsa, S. J. Fegan, A. Franckowiak, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, M.-H. Grondin, S. Guiriec, E. Hays, D. Horan, G. Jóhannesson, D. Kocevski, M. Kovac’evic’, M. Kuss, S. Larsson, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, J. E. McEnery, I. Mereu, P. F. Michelson, T. Mizuno, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, M. Ohno, N. Omodei, M. Orienti, E. Orlando, M. Palatiello, V. S. Paliya, D. Paneque, Z. Pei, M. Persic, M. Pesce-Rollins, V. Petrosian, F. Piron, H. Poon, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, A. Reimer, O. Reimer, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, H. Tajima, K. Takagi, D. Tak, D. F. Torres, J. Valverde, K. Wood, R. Yamazaki, M. Yassine, S. Zhu, Z. Lucas Uhm, Bing Zhang, Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Ajello, M., Arimoto, M., Asano, K., Axelsson, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berretta, A., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Bregeon, J., Bruel, P., Buehler, R., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Cavazzuti, E., Chen, S., Chiaro, G., Ciprini, S., Costantin, D., Cutini, S., D’Ammando, F., de la Torre Luque, P., de Palma, F., Di Lalla, N., Di Venere, L., Fana Dirirsa, F., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Grondin, M. -H., Guiriec, S., Hays, E., Horan, D., Jóhannesson, G., Kocevski, D., Kovac’Evic’, M., Kuss, M., Larsson, S., Latronico, L., Li, J., Liodakis, I., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., Mcenery, J. E., Mereu, I., Michelson, P. F., Mizuno, T., Monzani, M. E., Moretti, E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ohno, M., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Poon, H., Porter, T. A., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Razzano, M., Reimer, A., Reimer, O., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Tajima, H., Takagi, K., Tak, D., Torres, D. F., Valverde, J., Wood, K., Yamazaki, R., Yassine, M., Zhu, S., Lucas Uhm, Z., Zhang, Bing, and Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, Telescope, Spitzer Space Telescope, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, GRB131108A, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Gamma ray, Astronomy and Astrophysics, Light curve, 13. Climate action, Space and Planetary Science, ddc:520, Gamma-ray burst, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], gamma rays bursts, Fermi Gamma-ray Space Telescope, Flare
Abstract

GRB 131108A is a bright long Gamma-Ray Burst (GRB) detected by the Large Area Telescope and the Gamma-ray Burst Monitor on board the Fermi Gamma-ray Space Telescope. Dedicated temporal and spectral analyses reveal three $\gamma$-ray flares dominating above 100 MeV, which are not directly related to the prompt emission in the GBM band (10 keV - 10 MeV). The high-energy light curve of GRB 131108A (100 MeV - 10 GeV) shows an unusual evolution: a steep decay, followed by three flares with an underlying emission, and then a long-lasting decay phase. The detailed analysis of the $\gamma$-ray flares finds that the three flares are 6 - 20 times brighter than the underlying emission and are similar to each other. The fluence of each flare, (1.6 $\sim$ 2.0) $\times$ 10$^{-6}$ erg cm$^{-2}$, is comparable to that of emission during the steep decay phase, 1.7 $\times$ 10$^{-6}$ erg cm$^{-2}$. The total fluence from three $\gamma$-ray flares is 5.3 $\times$ 10$^{-6}$ erg cm$^{-2}$. The three $\gamma$-ray flares show properties similar to the usual X-ray flares that are sharp flux increases, occurring in $\sim$ 50\% of afterglows, in some cases well after the prompt emission. Also, the temporal and spectral indices during the early steep decay phase and the decaying phase of each flare show the consistency with a relation of the curvature effect ($\alpha$ = 2 + $\beta$), which is the first observational evidence of the high-latitude emission in the GeV energy band., Comment: ApJL, 10 pages, 3 figures, 2 tables

Published
2019

44. A Search for Cosmic-ray Proton Anisotropy with the Fermi Large Area Telescope

Author

Eleonora Troja, Soebur Razzaque, Ronaldo Bellazzini, Giacomo Principe, F. Piron, G. Chiaro, M. Kuss, Abhishek Desai, Kazuhiko Hayashi, Regina Caputo, T. A. Porter, E. Orlando, Dario Gasparrini, Hiroyasu Tajima, Keith Bechtol, S. Maldera, Stefano Ciprini, Ioannis Liodakis, E. J. Siskind, Francesco Longo, G. Martí-Devesa, Marco Ajello, J. B. Thayer, S. Rainò, Tsunefumi Mizuno, Matthew Meehan, Olaf Reimer, D. Horan, V. S. Paliya, D. Serini, Diego F. Torres, M. Razzano, Yasushi Fukazawa, Filippo D'Ammando, A. Reimer, Justin Vandenbroucke, G. Jóhannesson, F. de Palma, Manuel Meyer, Alessandro Cuoco, Guido Barbiellini, P. Fusco, I. Mereu, T. J. Brandt, Melissa Pesce-Rollins, Seth Digel, David A. Green, S. J. Fegan, Elizabeth Hays, Peter F. Michelson, Marcello Giroletti, D. J. Suson, S. Cutini, J. W. Hewitt, Eric Nuss, Sina Chen, Massimo Persic, Carmelo Sgrò, Riccardo Rando, G. Spandre, N. Di Lalla, Luca Baldini, Sylvain Guiriec, Mn Mazziotta, D. Costantin, Stephan Zimmer, David Paneque, Luca Latronico, P. de la Torre Luque, Elisabetta Bissaldi, Stefan Funk, Denis Bastieri, Eugenio Bottacini, Alberto Manfreda, Roger Blandford, Nicola Omodei, Johann Cohen-Tanugi, M. Orienti, L. Di Venere, F. Loparco, Nicola Giglietto, Aaron Dominguez, I. A. Grenier, E. Cavazzuti, M. Yassine, R. Bonino, Nestor Mirabal, P. Lubrano, S. Buson, J. Li, Matteo Negro, A. Morselli, R. A. Cameron, P. Bruel, Warit Mitthumsiri, P. Spinelli, Francesco Giordano, F. Gargano, Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Fermi-LAT, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buson, S., Cameron, R. A., Caputo, R., Cavazzuti, E., Chen, S., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cuoco, A., Cutini, S., D’Ammando, F., de la Torre Luque, P., de Palma, F., Desai, A., Digel, S. W., Di Lalla, N., Di Venere, L., Domínguez, A., Fegan, S. J., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guiriec, S., Hayashi, K., Hays, E., Hewitt, J. W., Horan, D., Jóhannesson, G., Kuss, M., Latronico, L., Li, J., Liodakis, I., Longo, F., Loparco, F., Lubrano, P., Maldera, S., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., Meehan, M., Mereu, I., Meyer, M., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Morselli, A., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Paliya, V. S., Paneque, D., Persic, M., Pesce-Rollins, M., Piron, F., Porter, T. A., Principe, G., Rainò, S., Rando, R., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Torres, D. F., Troja, E., Vandenbroucke, J., Yassine, M., Zimmer, S., Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Fermi-Lat Collaboration, T., D'Ammando, F., De La Torre Luque, P., De Palma, F., Dominguez, A., Johannesson, G., Marti-Devesa, G., Raino, S., Sgro, C., ITA, and USA

Subjects
010504 meteorology & atmospheric sciences, Proton, High-energy astronomy, Astrophysics::High Energy Astrophysical Phenomena, Galactic cosmic rays, High-energy astrophysics, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, cosmic radiation: anisotropy, GLAST, Galactic cosmic ray, law.invention, Telescope, Primary (astronomy), law, 0103 physical sciences, Nuclear Experiment, Anisotropy, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, cosmic radiation: primary, p: energy, 13. Climate action, Space and Planetary Science, p: cosmic radiation, anisotropy: dipole, ddc:520, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope
Abstract

The Fermi Large Area Telescope (LAT) has amassed a large data set of primary cosmic-ray protons throughout its mission. The LAT's wide field of view and full-sky survey capabilities make it an excellent instrument for studying cosmic-ray anisotropy. As a space-based survey instrument, the LAT is sensitive to anisotropy in both right ascension and declination, while ground-based observations only measure the anisotropy in right ascension. We present the results of the first ever proton anisotropy search using Fermi LAT. The data set uses eight years of data and consists of approximately 179 million protons above 78 GeV, enabling it to probe dipole anisotropy below an amplitude of $10^{-3}$, resulting in the most stringent limits on the declination dependence of the dipole to date. We measure a dipole amplitude $\delta = 3.9\pm1.5 \times 10^{-4}$ with a p-value of 0.01 (pre-trials) for protons with a minimum energy of 78 GeV. We discuss various systematic effects that could give rise to a dipole excess and calculate upper limits on the dipole amplitude as a function of minimum energy. The 95% CL upper limit on the dipole amplitude is $\delta_{UL}=1.3\times 10^{-3}$ for protons with a minimum energy of 78 GeV and $\delta_{UL}=1.2 \times 10^{-3}$ for protons with a minimum energy of 251 GeV., Comment: 15 pages, 11 figures, Contact authors: Matthew Meehan (mrmeehan@wisc.edu) and Justin Vandenbroucke (justin.vandenbroucke@wisc.edu)

Published
2019

45. On the Measurement of Handedness in Fermi Large Area Telescope Data

Author

Axel Brandenburg, G. Jóhannesson, and Julia Asplund

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Photon, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Helicity, Galaxy, law.invention, Interstellar medium, Telescope, Space and Planetary Science, law, 0103 physical sciences, Intergalactic travel, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Fermi Gamma-ray Space Telescope
Abstract

A handedness in the arrival directions of high-energy photons from outside our Galaxy can be related to the helicity of an intergalactic magnetic field. Previous estimates by arXiv:1310.4826 and arXiv:1412.3171 showed a hint of a signal present in the photons observed by the Fermi Large Area Telescope (LAT). An update on the measurement of handedness in Fermi-LAT data is presented using more than 10 years of observations. Simulations are performed to study the uncertainty of the measurements, taking into account the structure of the exposure caused by the energy-dependent instrument response and its observing profile, as well as the background from the interstellar medium. The simulations are required to accurately estimate the uncertainty and to show that previously the uncertainty was significantly underestimated. The apparent signal in the earlier analysis of {\em Fermi}-LAT data is rendered non-significant., 11 pages, 7 figures. Accepted for publication in ApJ

Published
2020

46. Galactic PeVatrons and helping to find them: Effects of galactic absorption on the observed spectra of very high energy γ -ray sources

Author

Igor V. Moskalenko, T. A. Porter, Gavin Rowell, and G. Jóhannesson

Subjects
Physics, Range (particle radiation), Astrophysics::High Energy Astrophysical Phenomena, Galactic Center, Cosmic microwave background, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Cherenkov Telescope Array, 01 natural sciences, Spectral line, Pair production, 0103 physical sciences, Absorption (logic), Astrophysics - High Energy Astrophysical Phenomena, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Energy (signal processing)
Abstract

Identification of the cosmic-ray (CR) `PeVatrons', which are sources capable of accelerating particles to $\sim10^{15}$ eV energies and higher, may lead to resolving the long-standing question of the origin of the spectral feature in the all-particle CR spectrum known as the `knee'. Because CRs with these energies are deflected by interstellar magnetic fields identification of individual sources and determination of their spectral characteristics is more likely via very high energy $\gamma$-ray emissions, which provide the necessary directional information. However, pair production on the interstellar radiation field (ISRF) and cosmic microwave background leads to steepening of the high-energy tails of $\gamma$-ray spectra, and should be corrected for to enable true properties of the spectrum at source to be recovered. Employing recently developed three-dimensional ISRF models this paper quantifies the pair-absorption effect on spectra for sources in the Galactic centre direction at 8.5 kpc and 23.5 kpc distance, with the latter corresponding to the far side of the Galactic stellar disc where it is expected that discrimination of spectral features $>10$ TeV will be possible by the forthcoming Cherenkov Telescope Array. The estimates made suggest spectral cutoffs could be underestimated by factors of a few in the energy range so far sampled by TeV $\gamma$-ray telescopes. As an example to illustrate this, the recent HESS measurements of diffuse $\gamma$-ray emissions possibly associated with injection of CRs nearby Sgr A$^*$ are ISRF-corrected, and estimates of the spectral cutoff are re-evaluated. It is found that it could be higher by up to a factor $\sim 2$, indicating that these emissions may be consistent with a CR accelerator with a spectral cutoff of at least 1 PeV at the 95% confidence level., Comment: 6 pages, 3 figures. Accepted by Physical Review D, Rapid Communications

Published
2018

47. Search for Spatial Extension in High-Latitude Sources Detected by the Fermi Large Area Telescope

Author

R. Buehler, J. Li, Marcello Giroletti, G. Tosti, I. A. Grenier, Regina Caputo, Soebur Razzaque, M. N. Mazziotta, E. Cavazzuti, Anna Franckowiak, Justin D. Finke, David H. Green, S. Rainò, Tsunefumi Mizuno, Hiroyasu Tajima, Yasushi Fukazawa, P. Fusco, Gloria Spandre, T. J. Brandt, E. Hays, Diego F. Torres, Marco Ajello, J. B. Thayer, M. Vogel, C. C. Cheung, G. Jóhannesson, J. Valverde, P. Lubrano, Jonathan Biteau, T. Reposeur, J. D. Magill, Manuel Meyer, Nicola Omodei, Johann Cohen-Tanugi, L. Di Venere, Melissa Pesce-Rollins, N. Di Lalla, M. Lemoine-Goumard, Luca Baldini, Bindu Rani, M. Palatiello, Stefano Ciprini, Luca Latronico, Sylvain Guiriec, T. A. Porter, F. Piron, R. Bonino, D. Costantin, Abhishek Desai, A. Reimer, Elliott D. Bloom, Vaidehi S. Paliya, L. Guillemot, S. Cutini, F. Loparco, J. F. Ormes, E. Orlando, Igor V. Moskalenko, Eric Charles, Ronaldo Bellazzini, D. J. Suson, K. S. Wood, Olaf Reimer, D. Horan, M. E. Monzani, Dario Gasparrini, J. S. Perkins, Roger Blandford, Eugenio Bottacini, Gabrijela Zaharijas, Alberto Manfreda, Massimo Persic, J. Ballet, C. Favuzzi, Nicola Giglietto, Francesco Longo, Elisabetta Bissaldi, Filippo D'Ammando, S. Kensei, Matteo Negro, A. Morselli, E. J. Siskind, J. Bregeon, J. W. Hewitt, Guido Barbiellini, Denis Bastieri, Julie McEnery, M. Orienti, Markus Ackermann, M. N. Lovellette, P. A. Caraveo, S. Maldera, L. Tibaldo, F. Gargano, Stefan Larsson, M. Di Mauro, P. Spinelli, Francesco Giordano, R. A. Cameron, P. Bruel, Tonia M. Venters, Matthew Wood, Daniel Castro, F. de Palma, G. Chiaro, Carmelo Sgrò, Riccardo Rando, E. Nuss, David Paneque, M. Kuss, Stefan Funk, Giacomo Principe, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Charles, E., Cheung, C. C., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D'Ammando, F., De Palma, F., Desai, A., Di Lalla, N., Di Mauro, M., Di Venere, L., Favuzzi, C., Finke, J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Jóhannesson, G., Kensei, S., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Mcenery, J. E., Meyer, M., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Palatiello, M., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Piron, F., Porter, T. A., Principe, G., Rainò, S., Rando, R., Rani, B., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Tibaldo, L., Torres, D. F., Tosti, G., Valverde, J., Venters, T. M., Vogel, M., Wood, K., Wood, M., Zaharijas, G., Biteau, J., Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and ITA

Subjects
catalog, Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, BL Lacertae objects: general, catalogs, gamma rays: general, ISM: H II Regions, ISM: supernova remnants, 01 natural sciences, law.invention, Telescope, law, 0103 physical sciences, Astronomy and Astrophysics, Space and Planetary Science, H II Region [ISM], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Background radiation, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, general [BL Lacertae objects], Astronomy and Astrophysic, Supernova, Crab Nebula, [SDU]Sciences of the Universe [physics], ISM: H ii Regions, ddc:520, Intergalactic travel, supernova remnant [ISM], Halo, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, general [gamma rays], Fermi Gamma-ray Space Telescope
Abstract

The astrophysical journal / Supplement series 237(2), 32 (2018). doi:10.3847/1538-4365/aacdf7, We present a search for spatial extension in high-latitude ($| b| \gt 5^\circ $) sources in recent Fermi point source catalogs. The result is the Fermi High-Latitude Extended Sources Catalog, which provides source extensions (or upper limits thereof) and likelihood profiles for a suite of tested source morphologies. We find 24 extended sources, 19 of which were not previously characterized as extended. These include sources that are potentially associated with supernova remnants and star-forming regions. We also found extended $γ$-ray emission in the vicinity of the Cen A radio lobes and—at GeV energies for the first time—spatially coincident with the radio emission of the SNR CTA 1, as well as from the Crab Nebula. We also searched for halos around active galactic nuclei, which are predicted from electromagnetic cascades induced by the $e^+ e^−$ pairs that are deflected in intergalactic magnetic fields. These pairs are produced when γ-rays interact with background radiation fields. We do not find evidence for extension in individual sources or in stacked source samples. This enables us to place limits on the flux of the extended source components, which are then used to constrain the intergalactic magnetic field to be stronger than $3 × 10^{−16} G$ for a coherence length $λ \gtrsim$ 10 kpc, even when conservative assumptions on the source duty cycle are made. This improves previous limits by several orders of magnitude., Published by IOP, Chicago, Ill. [u.a.]

Published
2018

48. Investigating the Nature of Late-Time High-Energy GRB Emission Through Joint Fermi\Swift Observations

Author

Daniel Kocevski, Giacomo Principe, Elisabetta Bissaldi, Vaidehi S. Paliya, P. Spinelli, M. E. Monzani, Melissa Pesce-Rollins, Francesco Giordano, G. Tosti, M. Vogel, Matteo Negro, A. Morselli, F. Piron, N. Di Lalla, Luca Baldini, Sylvain Guiriec, Diego F. Torres, D. Costantin, C. Holt, Olaf Reimer, Carmelo Sgrò, Riccardo Rando, Nicola Omodei, G. La Mura, P. Fusco, Stefan Larsson, Aaron Dominguez, G. Jóhannesson, Guido Barbiellini, I. A. Grenier, R. A. Cameron, P. Lubrano, Stefano Ciprini, M. Kuss, David H. Green, P. Bruel, Denis Bastieri, E. J. Siskind, M. Razzano, Soebur Razzaque, Marco Ajello, Gloria Spandre, C. Favuzzi, Dario Gasparrini, Ronaldo Bellazzini, J. B. Thayer, M. N. Mazziotta, Filippo D'Ammando, Stefan Funk, J. Valverde, Regina Caputo, J. D. Magill, Massimo Persic, Francesco Longo, J. S. Perkins, M. Orienti, F. Loparco, Eric Nuss, K. S. Wood, D. Tak, R. Buehler, Nicola Giglietto, Johan Bregeon, S. Maldera, D. Horan, J. L. Racusin, Anna Franckowiak, R. Bonino, A. Reimer, S. Rainò, J. Li, Peter F. Michelson, Marcello Giroletti, Eugenio Bottacini, Tsunefumi Mizuno, P. A. Caraveo, Alberto Manfreda, Johann Cohen-Tanugi, F. Gargano, Roger Blandford, F. de Palma, M. Di Mauro, G. Chiaro, L. Di Venere, Yasushi Fukazawa, E. Orlando, Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands (HÍ), University of Iceland (UI), ITA, Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Bregeon, J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., D'Ammando, F., De Palma, F., Di Lalla, N., Di Mauro, M., Di Venere, L., Dominguez, A., Favuzzi, C., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guiriec, S., Holt, C., Horan, D., Jóhannesson, G., Kocevski, D., Kuss, M., Mura, G. La, Larsson, S., Li, J., Longo, F., Loparco, F., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Paliya, V. S., Perkins, J. S., Persic, M., Pesce-Rollins, M., Piron, F., Principe, G., Racusin, J. L., Raino, S., Rando, R., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Tak, D., Thayer, J. B., Torres, D. F., Tosti, G., Valverde, J., Vogel, M., Wood, K., Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), and Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Sjónaukar, long-lived, Gammageislar, Astrophysics::High Energy Astrophysical Phenomena, Population, gamma-ray burst: general, electron: relativistic, FOS: Physical sciences, magnetic field, Gamma-ray burst: general, Astronomy and Astrophysics, Space and Planetary Science, Astrophysics, general [gamma-ray burst], gamma ray: burst, 7. Clean energy, 01 natural sciences, GLAST, law.invention, Telescope, law, 0103 physical sciences, synchrotron, ddc:530, X-ray: emission, energy: density, education, Gamma-ray burst, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, energy: high, 010308 nuclear & particles physics, Gamma ray, Compton scattering, Astronomy and Astrophysic, Synchrotron, Afterglow, electron: spectrum, flux, electron synchrotron, spectral, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], X-ray: detector, Fermi Gamma-ray Space Telescope
Abstract

Publisher's version (útgefin grein)., We use joint observations by the Swift X-ray Telescope (XRT) and the Fermi Large Area Telescope (LAT) of gamma-ray burst (GRB) afterglows to investigate the nature of the long-lived high-energy emission observed by Fermi LAT. Joint broadband spectral modeling of XRT and LAT data reveals that LAT nondetections of bright X-ray afterglows are consistent with a cooling break in the inferred electron synchrotron spectrum below the LAT and/or XRT energy ranges. Such a break is sufficient to suppress the high-energy emission so as to be below the LAT detection threshold. By contrast, LAT-detected bursts are best fit by a synchrotron spectrum with a cooling break that lies either between or above the XRT and LAT energy ranges. We speculate that the primary difference between GRBs with LAT afterglow detections and the nondetected population may be in the type of circumstellar environment in which these bursts occur, with late-time LAT detections preferentially selecting GRBs that occur in low wind-like circumburst density profiles. Furthermore, we find no evidence of high-energy emission in the LATdetected population significantly in excess of the flux expected from the electron synchrotron spectrum fit to the observed X-ray emission. The lack of excess emission at high energies could be due to a shocked external medium in which the energy density in the magnetic field is stronger than or comparable to that of the relativistic electrons behind the shock, precluding the production of a dominant synchrotron self-Compton (SSC) component in the LAT energy range. Alternatively, the peak of the SSC emission could be beyond the 0.1–100 GeV energy range considered for this analysis., Funding text #1 46 Funded by contract FIRB-2012-RBFR12PM1F from the Italian Ministry of Education, University and Research (MIUR). 47 https://fermi.gsfc.nasa.gov/ssc/observations/types/grbs/lat_grbs/ Funding text #2 The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT, as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States; the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy; the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK), and Japan Aerospace Exploration Agency (JAXA) in Japan; and the K.A.Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Funding text #3 Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515.

Published
2018
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49. Fermi-LAT Observations of LIGO/Virgo Event GW170817

Author

G. Chiaro, Marco Ajello, Diego F. Torres, Stefano Ciprini, J. B. Thayer, G. Jóhannesson, E. Moretti, Eleonora Troja, Nicola Omodei, Ronaldo Bellazzini, R. Buehler, E. J. Siskind, J. F. Ormes, Chong Yang, L. Guillemot, E. Orlando, T. J. Brandt, Stefan Funk, J. Li, Peter F. Michelson, Magnus Axelsson, L. R. Cominsky, Igor V. Moskalenko, Elliott D. Bloom, S. Cutini, A. A. Moiseev, Marcello Giroletti, Olaf Reimer, D. Horan, F. Loparco, Carmelo Sgrò, Riccardo Rando, A. Chekhtman, Johan Bregeon, P. Lubrano, Francesco Longo, I. A. Grenier, E. Cavazzuti, David H. Green, R. A. Cameron, J. L. Racusin, A. Reimer, Nicola Giglietto, E. Nuss, David Paneque, C. Favuzzi, Gloria Spandre, M. Kuss, Vahé Petrosian, Giacomo Principe, James Chiang, F. de Palma, F. Gargano, Johann Cohen-Tanugi, P. Fusco, L. Di Venere, Roger Blandford, Hiroyasu Tajima, Roopesh Ojha, Gabrijela Zaharijas, Denis Bastieri, Luca Latronico, K. S. Wood, J. G. Thayer, M. Di Mauro, Gino Tosti, D. Dumora, Elizabeth C. Ferrara, B. Berenji, Giacomo Vianello, M. N. Lovellette, P. A. Caraveo, J. M. Casandjian, R. Bonino, J. Granot, Steven Ritz, D. J. Suson, T. H. Burnett, C. C. Cheung, F. Piron, J. Valverde, Alice K. Harding, Melissa Pesce-Rollins, Tonia M. Venters, G. La Mura, Regina Caputo, N. Di Lalla, Luca Baldini, M. Takahashi, M. Palatiello, M. E. Monzani, M. N. Mazziotta, D. Tak, Sylvain Guiriec, R. Gill, Anna Franckowiak, D. Costantin, S. Rainò, Tsunefumi Mizuno, Vaidehi S. Paliya, Yasushi Fukazawa, P. M. Saz Parkinson, J. D. Magill, Soebur Razzaque, Alice Allafort, Elisabetta Bissaldi, P. Bruel, Matthew G. Baring, Sara Buson, T. A. Porter, Daniel Kocevski, Fumiya Imazato, T. Glanzman, R. Dubois, E. Hays, P. Spinelli, Francesco Giordano, F. Spada, Eugenio Bottacini, Alberto Manfreda, Dario Gasparrini, Stefan Larsson, M. Razzano, Filippo D'Ammando, Alessandro Cuoco, M.-H. Grondin, S. Maldera, T. Kamae, Eleonora Torresi, Massimo Persic, Felix Ryde, Guido Barbiellini, L. S. Rochester, S. Kensei, Matteo Negro, A. Morselli, ITA, Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Ajello, M., Allafort, A., Axelsson, M., Baldini, L., Barbiellini, G., Baring, M. G., Bastieri, D., Bellazzini, R., Berenji, B., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Burnett, T. H., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Casandjian, J. M., Cavazzuti, E., Chekhtman, A., Cheung, C. C., Chiang, J., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Cominsky, L. R., Costantin, D., Cuoco, A., Cutini, S., D'Ammando, F., Palma, F. De, Lalla, N. Di, Mauro, M. Di, Venere, L. Di, Dubois, R., Dumora, D., Favuzzi, C., Ferrara, E. C., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Gill, R., Giordano, F., Giroletti, M., Glanzman, T., Granot, J., Green, D., Grenier, I. A., Grondin, M. -H., Guillemot, L., Guiriec, S., Harding, A. K., Hays, E., Horan, D., Imazato, F., Jóhannesson, G., Kamae, T., Kensei, S., Kocevski, D., Kuss, M., Mura, G. La, Larsson, S., Latronico, L., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Michelson, P. F., Mizuno, T., Moiseev, A. A., Monzani, M. E., Moretti, E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Omodei, N., Orlando, E., Ormes, J. F., Palatiello, M., Paliya, V. S., Paneque, D., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Racusin, J. L., Raino, S., Rando, R., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Ritz, S., Rochester, L. S., Ryde, F., Parkinson, P. M. Saz, Sgro, C., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Takahashi, M., Tak, D., Thayer, J. G., Thayer, J. B., Torres, D. F., Torresi, E., Tosti, G., Troja, E., Valverde, J., Venters, T. M., Vianello, G., Wood, K., Yang, C., Zaharijas, G., Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)

Subjects
neutron star: binary, Gammageislar, gamma-ray burst: general, Astrophysics, general [gamma-ray burst], 01 natural sciences, Gamma-ray, Luminosity, gamma rays: general, gravitational waves, gamma ray: flux, LIGO, gravitational wave, 010303 astronomy & astrophysics, Physics, energy: high, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Gamma-ray burst: general, Astrophysics::High Energy Astrophysical Phenomena, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, gamma ray: burst, gravitational radiation: direct detection, GLAST, Gravitational waves, binary: coalescence, 0103 physical sciences, ddc:530, 010306 general physics, Gamma-ray burst, Astrophysics::Galaxy Astrophysics, Gravitational wave, Astronomy and Astrophysics, trigger, Astronomy and Astrophysic, Stjarneðlisfræði, redshift, Redshift, gravitational radiation detector, Neutron star, electromagnetic, VIRGO, [SDU]Sciences of the Universe [physics], Space and Planetary Science, gravitational radiation: emission, ddc:520, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [gamma rays], Fermi Gamma-ray Space Telescope
Abstract

Publisher's version (útgefin grein), We present the Fermi Large Area Telescope (LAT) observations of the binary neutron star merger event GW170817 and the associated short gamma-ray burst (SGRB) GRB 170817A detected by the Fermi Gamma-ray Burst Monitor. The LAT was entering the South Atlantic Anomaly at the time of the LIGO/Virgo trigger (t GW) and therefore cannot place constraints on the existence of high-energy (E > 100 MeV) emission associated with the moment of binary coalescence. We focus instead on constraining high-energy emission on longer timescales. No candidate electromagnetic counterpart was detected by the LAT on timescales of minutes, hours, or days after the LIGO/Virgo detection. The resulting flux upper bound (at 95% C.L.) from the LAT is 4.5 × 10−10 erg cm−2 s−1 in the 0.1–1 GeV range covering a period from t GW + 1153 s to t GW + 2027 s. At the distance of GRB 170817A, this flux upper bound corresponds to a luminosity upper bound of 9.7 × 1043 erg s−1, which is five orders of magnitude less luminous than the only other LAT SGRB with known redshift, GRB 090510. We also discuss the prospects for LAT detection of electromagnetic counterparts to future gravitational-wave events from Advanced LIGO/Virgo in the context of GW170817/GRB 170817A., This work performed in part under DOE Contract DE-AC02-76SF00515.

Published
2018

50. Minute-timescale >100 MeV γ-Ray Variability during the Giant Outburst of Quasar 3C 279 Observed by Fermi-LAT in 2015 June

Author

M. Caragiulo, R. Bonino, Nestor Mirabal, M. Sikora, Seth Digel, F. Spada, Dario Gasparrini, S. Maldera, F. Costanza, D. J. Thompson, Tsunefumi Mizuno, Richard Anantua, S. Cutini, J. D. Magill, P. Spinelli, J. Becerra González, Elisabetta Bissaldi, G. Chiaro, G. Pivato, Francesco Longo, P. Fusco, Yasushi Fukazawa, T. A. Porter, Ronaldo Bellazzini, E. Orlando, Daniel Kocevski, Igor V. Moskalenko, Nicola Giglietto, Lucas Guillemot, D. Horan, M. Hayashida, Yasunobu Uchiyama, Guido Barbiellini, M. Di Mauro, Lukasz Stawarz, C. Favuzzi, M. N. Lovellette, P. A. Caraveo, Soebur Razzaque, Francesco Giordano, Persis S. Drell, Shanta M. Zimmer, Carmelo Sgrò, Riccardo Rando, I. A. Grenier, Diego F. Torres, R. A. Cameron, D. Simone, E. Nuss, David Paneque, S. Funk, G. La Mura, Krzysztof Nalewajko, G. Jóhannesson, M. Kuss, P. Bruel, M. Razzano, Filippo D'Ammando, Denis Bastieri, E. Hays, F. Loparco, Yajie Yuan, J. S. Perkins, R. Buehler, James Chiang, Roger Blandford, J. Li, Marcello Giroletti, S. Kensei, Matteo Negro, A. Morselli, Stefan Larsson, F. de Palma, M. E. Monzani, Melissa Pesce-Rollins, R. Desiante, Eugenio Bottacini, A. Reimer, Alberto Manfreda, J. B. Thayer, Claudia Cecchi, Luca Baldini, Sylvain Guiriec, N. Di Lalla, Mn Mazziotta, P. F. Michelson, S. J. Fegan, Jeffrey D. Scargle, T. Ohsugi, B. Lott, F. Piron, G. M. Madejski, Katsuaki Asano, P. Lubrano, Stefano Ciprini, E. Troja, M. Mayer, Elliott D. Bloom, Luca Latronico, Elizabeth C. Ferrara, E. J. Siskind, Markus Ackermann, F. Gargano, C. C. Cheung, E. Cavazzuti, Johann Cohen-Tanugi, L. Di Venere, G. A. Caliandro, Giacomo Principe, ITA, Ackermann, M, Anantua, R., Asano, K., Baldini, L., Barbiellini, G., Bastieri, D., Gonzalez, J. Becerra, Bellazzini, R., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bonino, R., Bottacini, E., Bruel, P., Buehler, R., Caliandro, G. A., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cavazzuti, E., Cecchi, C., Cheung, C. C., Chiang, J., Chiaro, G., Ciprini, S., Cohen Tanugi, J., Costanza, F., Cutini, S., D'Ammando, F., Palma, F. De, Desiante, R., Digel, S. W., Lalla, N. Di, Mauro, M. Di, Venere, L. Di, Drell, P. S., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Grenier, I. A., Guillemot, L., Guiriec, S., Hayashida, M., Hays, E., Horan, D., Jóhannesson, G., Kensei, S., Kocevski, D., Kuss, M., Mura, G. La, Larsson, S., Latronico, L., Li, J., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Magill, J. D., Maldera, S., Manfreda, A., Mayer, M., Mazziotta, M. N., Michelson, P. F., Mirabal, N., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Nalewajko, K., Negro, M., Nuss, E., Ohsugi, T., Orlando, E., Paneque, D., Perkins, J. S., Pesce Rollins, M., Piron, F., Pivato, G., Porter, T. A., Principe, G., Rando, R., Razzano, M., Razzaque, S., Reimer, A., Scargle, J. D., Sgr, C., Sikora, M., Simone, D., Siskind, E. J., Spada, F., Spinelli, P., Stawarz, L., Thayer, J. B., Thompson, D. J., Torres, D. F., Troja, E., Uchiyama, Y., Yuan, Y., Zimmer, S., Ackermann M, Anantua R, Asano K, Baldini L, Barbiellini G, Bastieri D, Gonzalez JB, Bellazzini R, Bissaldi E, Blandford RD, Bloom ED, Bonino R, Bottacini E, Bruel P, Buehler R, Caliandro GA, Cameron RA, Caragiulo M, Caraveo PA, Cavazzuti E, Cecchi C, Cheung CC, Chiang J, Chiaro G, Ciprini S, Cohen-Tanugi J, Costanza F, Cutini S, DAmmando F, De Palma F, Desiante R, Digel SW, Di Lalla N, Di Mauro M, Di Venere L, Drell PS, Favuzzi C, Fegan SJ, Ferrara EC, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giordano F, Giroletti M, Grenier IA, Guillemot L, Guiriec S, Hayashida M, Hays E, Horan D, Johannesson G, Kensei S, Kocevski D, Kuss M, La Mura G, Larsson S, Latronico L, Li J, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Magill JD, Maldera S, Manfreda A, Mayer M, Mazziotta MN, Michelson PF, Mirabal N, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Nalewajko K, Negro M, Nuss E, Ohsugi T, Orlando E, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Principe G, Rando R, Razzano M, Razzaque S, Reimer A, Scargle JD, Sgro C, Sikora M, Simone D, Siskind EJ, Spada F, Spinelli P, Stawarz L, Thayer JB, Thompson DJ, Torres DF, Troja E, Uchiyama Y, Yuan Y, and Zimmer S

Subjects
Space and Planetary Science, Astronomy and Astrophysics, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, jets [galaxies], Astrophysics, galaxies: active – galaxies: jets – gamma rays: galaxies – quasars: individual (3C 279) – radiation mechanisms: non-thermal, 01 natural sciences, 7. Clean energy, Luminosity, quasars: individual (3C 279), symbols.namesake, 0103 physical sciences, gamma rays: galaxies, individual: 3C 279 [quasars], Absorption (logic), 010306 general physics, Blazar, 010303 astronomy & astrophysics, Physics, Quasar, Astronomy and Astrophysic, galaxies: jets, radiation mechanisms: non-thermal, Orbital period, non-thermal [radiation mechanisms], Astrophysics - Astrophysics of Galaxies, Lorentz factor, 13. Climate action, active [galaxies], galaxies [gamma rays], symbols, ddc:520, Production (computer science), Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract

On 2015 June 16, Fermi-LAT observed a giant outburst from the flat spectrum radio quasar 3C 279 with a peak $>100$ MeV flux of $\sim3.6\times10^{-5}\;{\rm photons}\;{\rm cm}^{-2}\;{\rm s}^{-1}$ averaged over orbital period intervals. It is the historically highest $\gamma$-ray flux observed from the source including past EGRET observations, with the $\gamma$-ray isotropic luminosity reaching $\sim10^{49}\;{\rm erg}\;{\rm s}^{-1}$. During the outburst, the Fermi spacecraft, which has an orbital period of 95.4 min, was operated in a special pointing mode to optimize the exposure for 3C 279. For the first time, significant flux variability at sub-orbital timescales was found in blazar observations by Fermi-LAT. The source flux variability was resolved down to 2-min binned timescales, with flux doubling times less than 5 min. The observed minute-scale variability suggests a very compact emission region at hundreds of Schwarzschild radii from the central engine in conical jet models. A minimum bulk jet Lorentz factor ($\Gamma$) of 35 is necessary to avoid both internal $\gamma$-ray absorption and super-Eddington jet power. In the standard external-radiation-Comptonization scenario, $\Gamma$ should be at least 50 to avoid overproducing the synchrotron-self-Compton component. However, this predicts extremely low magnetization ($\sim5\times10^{-4}$). Equipartition requires $\Gamma$ as high as 120, unless the emitting region is a small fraction of the dissipation region. Alternatively, we consider $\gamma$ rays originating as synchrotron radiation of $\gamma_{\rm e}\sim1.6\times10^6$ electrons, in magnetic field $B\sim1.3$ kG, accelerated by strong electric fields $E\sim B$ in the process of magnetoluminescence. At such short distance scales, one cannot immediately exclude production of $\gamma$ rays in hadronic processes., Comment: 8 pages, 4 figures. Accepted for publication in ApJ Letter. --Corresponding authors: Masaaki Hayashida (mahaya_at_icrr.u-tokyo.ac.jp), Greg Madejski (madejski_at_slac.stanford.edu), and Krzysztof Nalewajko (knalew_at_camk.edu.pl)

Published
2016

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