Browsing by Author "S. Buson"
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Publication Metadata only 2FHL: The SECOND CATALOG of HARD FERMI-LAT SOURCES(2016-01-01) M. Ackermann; M. Ajello; W. B. Atwood; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; J. Becerra Gonzalez; 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; E. Cavazzuti; C. Cecchi; E. Charles; A. Chekhtman; C. C. Cheung; J. Chiang; G. Chiaro; S. Ciprini; J. M. Cohen; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; A. Cuoco; S. Cutini; F. D'Ammando; A. De Angelis; F. De Palma; R. Desiante; M. Di Mauro; L. Di Venere; A. Domínguez; P. S. Drell; C. Favuzzi; S. J. Fegan; E. C. Ferrara; W. B. Focke; P. Fortin; A. Franckowiak; Y. Fukazawa; S. Funk; A. K. Furniss; P. Fusco; F. Gargano; D. Gasparrini; N. Giglietto; P. Giommi; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; I. A. Grenier; M. H. Grondin; L. Guillemot; S. Guiriec; A. K. Harding; E. Hays; J. W. Hewitt; A. B. Hill; D. Horan; Deutsche Elektronen-Synchrotron; Clemson University; Santa Cruz Institute for Particle Physics; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Kavli Institute for Particle Astrophysics and Cosmology; Institut de Recherche sur les Lois Fondamentales de l'Univers; Istituto Nazionale di Fisica Nucleare, Roma; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; NASA Goddard Space Flight Center; University of Maryland; Università degli Studi di Torino; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; University of Maryland, Baltimore County; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); Università degli Studi di Bari; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Universita degli Studi di Perugia; George Mason University, Fairfax Campus; Naval Research Laboratory; Sonoma State University; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; Osservatorio Astronomico di Roma; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Università di Bologna; Università degli Studi di Napoli Federico II; Universita degli Studi di Udine; Harvard-Smithsonian Center for Astrophysics; Hiroshima University; Erlangen Centre for Astroparticle Physics; IN2P3 Institut National de Physique Nucleaire et de Physique des Particules; Universite d'Orleans; Institut National des Sciences de l'Univers; University of North Florida; University of Southampton; Osservatorio Astronomico di Trieste; University Science Institute Reykjavik; University of Tokyo; Waseda University; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; Medizinische Universitat Innsbruck; The Royal Institute of Technology (KTH); Universitat Autònoma de Barcelona© 2016. The American Astronomical Society. All rights reserved. We present a catalog of sources detected above 50 GeV by the Fermi-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass 8 event-level analysis allows the detection and characterization of sources in the 50 GeV-2 TeV energy range. In this energy band, Fermi-LAT has detected 360 sources, which constitute the second catalog of hard Fermi-LAT sources (2FHL). The improved angular resolution enables the precise localization of point sources (∼1.′7 radius at 68% C. L.) and the detection and characterization of spatially extended sources. We find that 86% of the sources can be associated with counterparts at other wavelengths, of which the majority (75%) are active galactic nuclei and the rest (11%) are Galactic sources. Only 25% of the 2FHL sources have been previously detected by Cherenkov telescopes, implying that the 2FHL provides a reservoir of candidates to be followed up at very high energies. This work closes the energy gap between the observations performed at GeV energies by Fermi-LAT on orbit and the observations performed at higher energies by Cherenkov telescopes from the ground.Publication Metadata only 3FHL: The Third Catalog of Hard Fermi-LAT Sources(2017-10-01) M. Ajello; W. B. Atwood; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; R. Bellazzini; E. Bissaldi; R. D. Blandford; E. D. Bloom; R. Bonino; J. Bregeon; R. J. Britto; P. Bruel; R. Buehler; S. Buson; R. A. Cameron; R. Caputo; M. Caragiulo; P. A. Caraveo; E. Cavazzuti; C. Cecchi; E. Charles; A. Chekhtman; C. C. Cheung; G. Chiaro; S. Ciprini; J. M. Cohen; D. Costantin; 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; A. Domnguez; P. S. Drell; D. Dumora; C. Favuzzi; S. J. Fegan; E. C. Ferrara; P. Fortin; 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; M. H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; A. K. Harding; E. Hays; J. W. Hewitt; D. Horan; G. Jóhannesson; S. Kensei; M. Kuss; G. La Mura; S. Larsson; L. Latronico; M. Lemoine-Goumard; J. Li; F. Longo; Clemson University; Santa Cruz Institute for Particle Physics; Università di Pisa; Universite Paris 7- Denis Diderot; Istituto Nazionale di Fisica Nucleare, Roma; Università degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Università degli Studi di Bari; Kavli Institute for Particle Astrophysics and Cosmology; Università degli Studi di Torino; Laboratoire Univers et Particules de Montpellier; University of the Free State; Laboratoire Leprince-Ringuet; Deutsche Elektronen-Synchrotron; NASA Goddard Space Flight Center; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Università degli Studi di Perugia; George Mason University, Fairfax Campus; Naval Research Laboratory; University of Maryland; Rheinisch-Westfälische Technische Hochschule Aachen; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Università di Bologna; Università degli Studi di Napoli Federico II; Università degli Studi di Udine; Universidad Complutense de Madrid; IN2P3 Institut National de Physique Nucleaire et de Physique des Particules; Harvard-Smithsonian Center for Astrophysics; Hiroshima University; Erlangen Centre for Astroparticle Physics; Universite d'Orleans; Institut National des Sciences de l'Univers; University of North Florida; University Science Institute Reykjavik; Nordisk Institut for Teoretisk Atomtysik; The Royal Institute of Technology (KTH); Oskar Klein Centre for Cosmoparticle Physics; Universitat Autònoma de Barcelona; Stockholms universitet; Mahidol University© 2017. The American Astronomical Society. All rights reserved.. We present a catalog of sources detected above 10 GeV by the Fermi Large Area Telescope (LAT) in the first 7 years of data using the Pass 8 event-level analysis. This is the Third Catalog of Hard Fermi-LAT Sources (3FHL), containing 1556 objects characterized in the 10 GeV-2 TeV energy range. The sensitivity and angular resolution are improved by factors of 3 and 2 relative to the previous LAT catalog at the same energies (1FHL). The vast majority of detected sources (79%) are associated with extragalactic counterparts at other wavelengths, including 16 sources located at very high redshift (z > 2). Of the sources, 8% have Galactic counterparts and 13% are unassociated (or associated with a source of unknown nature). The high-latitude sky and the Galactic plane are observed with a flux sensitivity of 4.4 to 9.5 ×10-11 ph cm-2 s-1, respectively (this is approximately 0.5% and 1% of the Crab Nebula flux above 10 GeV). The catalog includes 214 new γ-ray sources. The substantial increase in the number of photons (more than 4 times relative to 1FHL and 10 times to 2FHL) also allows us to measure significant spectral curvature for 32 sources and find flux variability for 163 of them. Furthermore, we estimate that for the same flux limit of 10-12 erg cm-2 s-1, the energy range above 10 GeV has twice as many sources as the range above 50 GeV, highlighting the importance, for future Cherenkov telescopes, of lowering the energy threshold as much as possible.Publication Metadata only Catalog of Long-term Transient Sources in the First 10 yr of Fermi-LAT Data(2021-09-01) The Fermi-Lat Collaboration; L. Baldini; J. Ballet; D. Bastieri; J. Becerra Gonzalez; R. Bellazzini; A. Berretta; E. Bissaldi; R. D. Blandford; E. D. Bloom; R. Bonino; E. Bottacini; P. Bruel; S. Buson; R. A. Cameron; P. A. Caraveo; E. Cavazzuti; S. Chen; G. Chiaro; D. Ciangottini; N. Cibario; S. Ciprini; P. Cristarella Orestano; M. Crnogorcevic; S. Cutini; F. D'Ammando; P. De La Torre Luque; F. De Palma; S. W. Digel; N. Di Lalla; F. Dirirsa; L. Di Venere; A. Domínguez; A. Fiori; H. Fleischhack; A. Franckowiak; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; F. Giordano; M. Giroletti; D. Green; I. A. Grenier; S. Griffin; S. Guiriec; M. Gustafsson; J. W. Hewitt; D. Horan; R. Imazawa; G. Jóhannesson; M. Kerr; D. Kocevski; 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; H. Matake; M. N. Mazziotta; I. Mereu; M. Meyer; N. Mirabal; W. Mitthumsiri; T. Mizuno; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Nagasawa; M. Negro; R. Ojha; M. Orienti; E. Orlando; M. Palatiello; V. Paliya; D. Paneque; Z. Pei; M. Persic; M. Pesce-Rollins; V. Petrosian; H. Poon; T. A. Porter; G. Principe; J. L. Racusin; S. Rain; R. Rando; B. Rani; M. Razzano; S. Razzaque; A. Reimer; Oskar Klein Centre; Istituto Nazionale di Fisica Nucleare, Sezione di Trieste; Istituto Nazionale di Fisica Nucleare, Sezione di Perugia; Istituto Nazionale di Fisica Nucleare, Sezione di Lecce; Istituto Nazionale di Fisica Nucleare, Sezione di Bari; Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tor Vergata; Istituto Nazionale di Fisica Nucleare, Sezione di Torino; Istituto Nazionale di Fisica Nucleare, Sezione di Pisa; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Universite Paris-Saclay; Aryabhatta Research Institute of Observational Sciences; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Korea Astronomy and Space Science Institute; Raunvísindastofnun Háskólans; Agenzia Spaziale Italiana; Georg-August-Universität Göttingen; Hiroshima University; Deutsches Elektronen-Synchrotron (DESY); Osservatorio Astronomico di Trieste; Università di Pisa; Politecnico di Bari; Universidad Complutense de Madrid; Naval Research Laboratory; Università degli Studi di Udine; SLAC National Accelerator Laboratory; The University of Tokyo; University of Maryland, Baltimore County (UMBC); Universita del Salento; Catholic University of America; American University; University of Maryland, College Park; Université Savoie Mont Blanc; Università degli Studi di Trieste; Högskolan Dalarna; École polytechnique; Mahidol University; Julius-Maximilians-Universität Würzburg; Istituto Di Radioastronomia, Bologna; Università degli Studi di Torino; NASA Marshall Space Flight Center; Instituto Astrofisico de Canarias; Universität Innsbruck; Max Planck Institute for Physics (Werner Heisenberg Institute); Turun yliopisto; NASA Goddard Space Flight Center; Ruhr-Universitat Bochum; The George Washington University; Università degli Studi di Perugia; The Royal Institute of Technology (KTH); Friedrich-Alexander-Universität Erlangen-Nürnberg; University of Johannesburg; Università degli Studi di Padova; University of North FloridaWe present the first Fermi Large Area Telescope (LAT) catalog of long-term γ-ray transient sources (1FLT). This comprises sources that were detected on monthly time intervals during the first decade of Fermi-LAT operations. The monthly timescale allows us to identify transient and variable sources that were not yet reported in other Fermi-LAT catalogs. The monthly data sets were analyzed using a wavelet-based source detection algorithm that provided the candidate new transient sources. The search was limited to the extragalactic regions of the sky to avoid the dominance of the Galactic diffuse emission at low Galactic latitudes. The transient candidates were then analyzed using the standard Fermi-LAT maximum likelihood analysis method. All sources detected with a statistical significance above 4σ in at least one monthly bin were listed in the final catalog. The 1FLT catalog contains 142 transient γ-ray sources that are not included in the 4FGL-DR2 catalog. Many of these sources (102) have been confidently associated with active galactic nuclei (AGNs): 24 are associated with flat-spectrum radio quasars, 1 with a BL Lac object, 70 with blazars of uncertain type, 3 with radio galaxies, 1 with a compact steep-spectrum radio source, 1 with a steep-spectrum radio quasar, and 2 with AGNs of other types. The remaining 40 sources have no candidate counterparts at other wavelengths. The median γ-ray spectral index of the 1FLT-AGN sources is softer than that reported in the latest Fermi-LAT AGN general catalog. This result is consistent with the hypothesis that detection of the softest γ-ray emitters is less efficient when the data are integrated over year-long intervals.Publication Metadata only Fermi and Swift Observations of GRB 190114C: Tracing the Evolution of High-energy Emission from Prompt to Afterglow(2020-02-10) 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. Rain; R. Rando; Istituto Nazionale di Fisica Nucleare, Sezione di Trieste; Istituto Nazionale di Fisica Nucleare, Sezione di Perugia; Istituto Nazionale di Fisica Nucleare, Sezione di Bari; Istituto Nazionale di Fisica Nucleare, Sezione di Torino; Istituto Nazionale di Fisica Nucleare, Sezione di Pisa; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Laboratoire Univers et Particules de Montpellier; Universite Paris-Saclay; Laboratoire Leprince-Ringuet; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; University Science Institute Reykjavik; Centre d'Etudes Nucléaires de Bordeaux Gradignan; Agenzia Spaziale Italiana; Hiroshima University; Deutsches Elektronen-Synchrotron (DESY); Osservatorio Astronomico di Trieste; Università di Pisa; Stockholms universitet; Naval Research Laboratory; Clemson University; SLAC National Accelerator Laboratory; Kanazawa University; Universitat Autònoma de Barcelona; Università degli Studi di Bari; Open University of Israel; Istituto Nazionale di Fisica Nucleare - INFN; University of Maryland; Università degli Studi di Trieste; Högskolan Dalarna; Mahidol University; Julius-Maximilians-Universität Würzburg; Istituto Di Radioastronomia, Bologna; Università degli Studi di Torino; NASA Marshall Space Flight Center; Max Planck Institute for Physics (Werner Heisenberg Institute); Medizinische Universitat Innsbruck; NASA Goddard Space Flight Center; The George Washington University; Università degli Studi di Perugia; The Royal Institute of Technology (KTH); Friedrich-Alexander-Universität Erlangen-Nürnberg; University of Johannesburg; Università degli Studi di Padova; Stellar Solutions, Inc.© 2020. The American Astronomical Society.. 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.Publication Metadata only Fermi establishes classical novae as a distinct class of gamma-ray sources: The Fermi-LAT collaboration(2014-08-01) M. Ermann; M. Ajello; A. Albert; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; R. Bellazzini; E. Bissaldi; R. D. Blandford; E. D. Bloom; E. Bottacini; T. J. Brandt; J. Bregeon; P. Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; M. Caragiulo; P. A. Caraveo; E. Cavazzuti; E. Charles; A. Chekhtman; C. C. Cheung; J. Chiang; G. Chiaro; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Corbel; F. D'Ammando; A. De Angelis; P. R. Den Hartog; F. De Palma; C. D. Dermer; R. Desiante; S. W. Digel; L. Di Venere; E. Do Couto E Silva; D. Donato; P. S. Drell; A. Drlica-Wagner; C. Favuzzi; E. C. Ferrara; W. B. Focke; A. Franckowiak; L. Fuhrmann; Y. Fukazawa; P. Fusco; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; I. A. Grenier; J. E. Grove; S. Guiriec; D. Hadasch; A. K. Harding; M. Hayashida; E. Hays; J. W. Hewitt; A. B. Hill; X. Hou; P. Jean; T. Jogler; G. Jóhannesson; A. S. Johnson; W. N. Johnson; M. Kerr; J. Knödlseder; Deutsche Elektronen-Synchrotron; Clemson University; Kavli Institute for Particle Astrophysics and Cosmology; Istituto Nazionale di Fisica Nucleare, Roma; Institut de Recherche sur les Lois Fondamentales de l'Univers; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Universita degli Studi di Padova; NASA Goddard Space Flight Center; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; George Mason University, Fairfax Campus; Naval Research Laboratory; Osservatorio Astronomico di Roma; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; K. A. Wallenberg Foundation; Kungl. Vetenskapsakademien; Institut Universitaire de France; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Universita di Bologna; Universita degli Studi di Udine; Universita degli Studi di Bari; University of Maryland; Fermi National Accelerator Laboratory; Max Planck Institut fur Radioastronomie; Hiroshima University; Universita degli Studi di Perugia; NASA Postdoctoral Program Fellow; Medizinische Universitat Innsbruck; University of Tokyo; University of Maryland, Baltimore County; University of Southampton; Marie Curie IOF; Centre d'Etudes Nucleaires de Bordeaux Gradignan; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; University Science Institute Reykjavik; Australia Telescope National Facility; Yale University; Mahidol University; University of California, IrvineA classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in γ rays and stood in contrast to the first γ-ray-detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft-spectrum transient γ-ray sources detected over 2- to 3-week durations. The γ-ray detections point to unexpected high-energy particle acceleration processes linked to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic γ-ray sources.Publication Metadata only Fermi large area telescope detection of extended gamma-ray emission from the radio galaxy Fornax A(2016-07-20) M. Ackermann; M. Ajello; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; R. Bellazzini; E. Bissaldi; R. D. Blandford; E. D. Bloom; R. Bonino; T. J. Brandt; J. Bregeon; P. Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; M. Caragiulo; P. A. Caraveo; E. Cavazzuti; C. Cecchi; E. Charles; A. Chekhtman; C. C. Cheung; G. Chiaro; S. Ciprini; J. M. Cohen; J. Cohen-Tanugi; F. Costanza; S. Cutini; F. D'Ammando; D. S. Davis; A. De Angelis; F. De Palma; R. Desiante; S. W. Digel; N. Di Lalla; M. Di Mauro; L. Di Venere; C. Favuzzi; S. J. Fegan; E. C. Ferrara; W. B. Focke; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; M. Georganopoulos; N. Giglietto; F. Giordano; M. Giroletti; G. Godfrey; D. Green; I. A. Grenier; S. Guiriec; E. Hays; J. W. Hewitt; A. B. Hill; T. Jogler; G. Jóhannesson; S. Kensei; M. Kuss; S. Larsson; L. Latronico; J. Li; L. Li; F. Longo; F. Loparco; P. Lubrano; Deutsche Elektronen-Synchrotron; Clemson University; Università di Pisa; Kavli Institute for Particle Astrophysics and Cosmology; Institut de Recherche sur les Lois Fondamentales de l'Univers; Istituto Nazionale di Fisica Nucleare, Roma; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Università degli Studi di Torino; NASA Goddard Space Flight Center; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; University of Maryland, Baltimore County; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); Università degli Studi di Bari; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Universita degli Studi di Perugia; George Mason University, Fairfax Campus; Naval Research Laboratory; University of Maryland; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Università di Bologna; Universita degli Studi di Udine; Università degli Studi di Napoli Federico II; Hiroshima University; Erlangen Centre for Astroparticle Physics; University of North Florida; University of Southampton; University Science Institute Reykjavik; The Royal Institute of Technology (KTH); Oskar Klein Centre for Cosmoparticle Physics; Universitat Autònoma de Barcelona; Mahidol University; University of California, Irvine; University of Denver; Max Planck Institut fur Physik (Werner-Heisenberg-Institut)© 2016. The American Astronomical Society. All rights reserved. We report the Fermi Large Area Telescope detection of extended γ-ray emission from the lobes of the radio galaxy Fornax A using 6.1 years of Pass 8 data. After Centaurus A, this is now the second example of an extended γ-ray source attributed to a radio galaxy. Both an extended flat disk morphology and a morphology following the extended radio lobes were preferred over a point-source description, and the core contribution was constrained to be % of the total γ-ray flux. A preferred alignment of the γ-ray elongation with the radio lobes was demonstrated by rotating the radio lobes template. We found no significant evidence for variability on ∼0.5 year timescales. Taken together, these results strongly suggest a lobe origin for the γ-rays. With the extended nature of the γ-ray emission established, we model the source broadband emission considering currently available total lobe radio and millimeter flux measurements, as well as X-ray detections attributed to inverse Compton (IC) emission off the cosmic microwave background (CMB). Unlike the Centaurus A case, we find that a leptonic model involving IC scattering of CMB and extragalactic background light (EBL) photons underpredicts the γ-ray fluxes by factors of about ∼2-3, depending on the EBL model adopted. An additional γ-ray spectral component is thus required, and could be due to hadronic emission arising from proton-proton collisions of cosmic rays with thermal plasma within the radio lobes.Publication Metadata only Fermi Large Area Telescope Performance after 10 Years of Operation(2021-09-01) M. Ajello; W. B. Atwood; M. Axelsson; R. Bagagli; M. Bagni; L. Baldini; D. Bastieri; F. Bellardi; R. Bellazzini; E. Bissaldi; E. D. Bloom; R. Bonino; J. Bregeon; A. Brez; P. Bruel; R. Buehler; S. Buson; R. A. Cameron; P. A. Caraveo; E. Cavazzuti; M. Ceccanti; S. Chen; C. C. Cheung; S. Ciprini; I. Cognard; J. Cohen-Tanugi; S. Cutini; F. D'Ammando; P. De La Torre Luque; F. De Palma; S. W. Digel; F. Dirirsa; N. Di Lalla; L. Di Venere; A. Domínguez; D. Fabiani; E. C. Ferrara; A. Fiori; G. Foglia; Y. Fukazawa; P. Fusco; F. Gargano; D. Gasparrini; M. Giroletti; T. Glanzman; D. Green; S. Griffin; M. H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; M. Gustafsson; E. Hays; D. Horan; G. Jóhannesson; T. J. Johnson; T. Kamae; M. Kerr; 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; G. Martí-Devesa; M. N. Mazziotta; N. Menon; I. Mereu; M. Meyer; P. F. Michelson; M. Minuti; W. Mitthumsiri; T. Mizuno; M. Mongelli; M. E. Monzani; I. V. Moskalenko; M. Negro; E. Nuss; R. Ojha; M. Orienti; E. Orlando; A. Paccagnella; V. S. Paliya; D. Paneque; Z. Pei; J. S. Perkins; M. Pesce-Rollins; M. Pinchera; F. Piron; H. Poon; T. A. Porter; R. Primavera; G. Principe; J. L. Racusin; Oskar Klein Centre; Istituto Nazionale di Fisica Nucleare, Sezione di Trieste; Istituto Nazionale di Fisica Nucleare, Sezione di Perugia; Istituto Nazionale di Fisica Nucleare, Sezione di Lecce; Istituto Nazionale di Fisica Nucleare, Sezione di Bari; Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tor Vergata; Istituto Nazionale di Fisica Nucleare, Sezione di Torino; Istituto Nazionale di Fisica Nucleare, Sezione di Pisa; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Laboratoire Univers et Particules de Montpellier; Santa Cruz Institute for Particle Physics; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Raunvísindastofnun Háskólans; Laboratoire de Physique des 2 infinis de Bordeaux; Agenzia Spaziale Italiana; Georg-August-Universität Göttingen; Hiroshima University; Deutsches Elektronen-Synchrotron (DESY); Universite d'Orleans; Università di Pisa; Stockholms universitet; Politecnico di Bari; Universidad Complutense de Madrid; Naval Research Laboratory; Clemson University; Laboratoire de Physique Subatomique et de Cosmologie de Grenoble; SLAC National Accelerator Laboratory; The University of Tokyo; University of Maryland, Baltimore County (UMBC); Universita del Salento; University of Maryland, College Park; Université Savoie Mont Blanc; INSU - Institut National des Sciences de l'Univers; Università degli Studi di Trieste; George Mason University; Högskolan Dalarna; École polytechnique; Mahidol University; Julius-Maximilians-Universität Würzburg; Istituto Di Radioastronomia, Bologna; Università degli Studi di Torino; Universität Innsbruck; Max Planck Institute for Physics (Werner Heisenberg Institute); Turun yliopisto; NASA Goddard Space Flight Center; The George Washington University; Università degli Studi di Perugia; The Royal Institute of Technology (KTH); Friedrich-Alexander-Universität Erlangen-Nürnberg; Università degli Studi di PadovaThe 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 yr 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.Publication Metadata only FERMI-LAT OBSERVATIONS of HIGH-ENERGY γ-RAY EMISSION TOWARD the GALACTIC CENTER(2016-03-01) M. Ajello; A. Albert; W. B. Atwood; 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; S. Buson; G. A. Caliandro; R. A. Cameron; R. Caputo; M. Caragiulo; P. A. Caraveo; C. Cecchi; A. Chekhtman; J. Chiang; G. Chiaro; S. Ciprini; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; S. Cutini; F. D'Ammando; A. De Angelis; F. De Palma; R. Desiante; L. Di Venere; P. S. Drell; C. Favuzzi; E. C. Ferrara; P. Fusco; F. Gargano; D. Gasparrini; N. Giglietto; P. Giommi; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; G. A. Gomez-Vargas; I. A. Grenier; S. Guiriec; M. Gustafsson; A. K. Harding; J. W. Hewitt; A. B. Hill; D. Horan; T. Jogler; G. Jóhannesson; A. S. Johnson; T. Kamae; C. Karwin; J. Knödlseder; M. Kuss; S. Larsson; L. Latronico; J. Li; L. Li; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; Clemson University; Kavli Institute for Particle Astrophysics and Cosmology; Santa Cruz Institute for Particle Physics; Istituto Nazionale di Fisica Nucleare, Roma; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; University of Wisconsin Madison; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Università degli Studi di Torino; NASA Goddard Space Flight Center; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Deutsche Elektronen-Synchrotron; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Universita degli Studi di Perugia; George Mason University, Fairfax Campus; Agenzia Spaziale Italiana; Osservatorio Astronomico di Roma; Sonoma State University; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; Kungl. Vetenskapsakademien; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Università di Bologna; Universita degli Studi di Udine; Università degli Studi di Napoli Federico II; Università degli Studi di Bari; Pontificia Universidad Católica de Chile; Institut de Recherche sur les Lois Fondamentales de l'Univers; Universität Göttingen; University of North Florida; University of Southampton; University Science Institute Reykjavik; University of Tokyo; University of California, Irvine; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; The Royal Institute of Technology (KTH); Universitat Autònoma de Barcelona; Naval Research Laboratory; University of Maryland; Mahidol University; Hiroshima University; University of Denver; Max Planck Institut fur Physik (Werner-Heisenberg-Institut); The University of Hong Kong; Medizinische Universitat Innsbruck© 2016. The American Astronomical Society. All rights reserved. The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of the emission toward the Galactic center (GC) in high-energy γ-rays. This paper describes the analysis of data taken during the first 62 months of the mission in the energy range 1-100 GeV from a 15° × 15° region about the direction of the GC. Specialized interstellar emission models (IEMs) are constructed to enable the separation of the γ-ray emissions produced by cosmic ray particles interacting with the interstellar gas and radiation fields in the Milky Way into that from the inner ∼1 kpc surrounding the GC, and that from the rest of the Galaxy. A catalog of point sources for the 15° × 15° region is self-consistently constructed using these IEMs: the First Fermi-LAT Inner Galaxy Point Source Catalog (1FIG). The spatial locations, fluxes, and spectral properties of the 1FIG sources are presented, and compared with γ-ray point sources over the same region taken from existing catalogs. After subtracting the interstellar emission and point-source contributions a residual is found. If templates that peak toward the GC are used to model the positive residual the agreement with the data improves, but none of the additional templates tried account for all of its spatial structure. The spectrum of the positive residual modeled with these templates has a strong dependence on the choice of IEM.Publication Metadata only THE FIRST FERMI LAT SUPERNOVA REMNANT CATALOG(2016-05-01) F. Acero; M. Ackermann; M. Ajello; L. Baldini; J. Ballet; 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; J. M. Casandjian; E. Cavazzuti; C. Cecchi; A. Chekhtman; J. Chiang; G. Chiaro; S. Ciprini; R. Claus; J. M. Cohen; J. Cohen-Tanugi; L. R. Cominsky; B. Condon; J. Conrad; 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; 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; G. Godfrey; G. A. Gomez-Vargas; I. A. Grenier; M. H. Grondin; L. Guillemot; S. Guiriec; M. Gustafsson; D. Hadasch; A. K. Harding; M. Hayashida; E. Hays; J. W. Hewitt; A. B. Hill; D. Horan; X. Hou; Institut de Recherche sur les Lois Fondamentales de l'Univers; Deutsche Elektronen-Synchrotron; Clemson University; Università di Pisa; Kavli Institute for Particle Astrophysics and Cosmology; Istituto Nazionale di Fisica Nucleare, Roma; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Università degli Studi di Torino; NASA Goddard Space Flight Center; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); Santa Cruz Institute for Particle Physics; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Universita degli Studi di Perugia; George Mason University, Fairfax Campus; Osservatorio Astronomico di Roma; University of Maryland; Sonoma State University; Centre d'Etudes Nucleaires de Bordeaux Gradignan; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; Kungl. Vetenskapsakademien; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Università di Bologna; Universita degli Studi di Udine; Università degli Studi di Napoli Federico II; Università degli Studi di Bari; Fermi National Accelerator Laboratory; Hiroshima University; Erlangen Centre for Astroparticle Physics; Pontificia Universidad Católica de Chile; Universite d'Orleans; Institut National des Sciences de l'Univers; Universität Göttingen; Medizinische Universitat Innsbruck; University of Tokyo; University of North Florida; University of Southampton; Chinese Academy of Sciences; Osservatorio Astronomico di Trieste; University Science Institute Reykjavik; Ibaraki University; Waseda University; Australia Telescope National Facility; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; Twitter, Inc.; The Royal Institute of Technology (KTH); Universitat Autònoma de Barcelona; Naval Research Laboratory© 2016. The American Astronomical Society. All rights reserved. To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope (LAT). Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude allows us to determine an upper limit of 22% on the number of GeV candidates falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavelength (MW) data, including radio, X-ray, and TeV, we demonstrate the need for improvements to previously sufficient, simple models describing the GeV and radio emission from these objects. We model the GeV and MW emission from SNRs in aggregate to constrain their maximal contribution to observed Galactic cosmic rays.Publication Metadata only Gamma-Ray Blazars within the First 2 Billion Years(2017-03-01) M. Ackermann; M. Ajello; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; J. Becerra Gonzalez; R. Bellazzini; E. Bissaldi; R. D. Blandford; E. D. Bloom; R. Bonino; E. Bottacini; J. Bregeon; P. Bruel; R. Buehler; S. Buson; R. A. Cameron; M. Caragiulo; P. A. Caraveo; E. Cavazzuti; C. Cecchi; C. C. Cheung; J. Chiang; G. Chiaro; S. Ciprini; J. Conrad; D. Costantin; F. Costanza; S. Cutini; F. D'Ammando; F. De Palma; R. Desiante; S. W. Digel; N. Di Lalla; M. Di Mauro; L. Di Venere; A. Domínguez; P. S. Drell; C. Favuzzi; S. J. Fegan; E. C. Ferrara; J. Finke; W. B. Focke; 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. H. Hartmann; E. Hays; D. Horan; T. Jogler; G. Jóhannesson; A. S. Johnson; M. Kuss; G. La Mura; S. Larsson; L. Latronico; J. Li; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; J. D. Magill; S. Maldera; A. Manfreda; L. Marcotulli; M. N. Mazziotta; Deutsche Elektronen-Synchrotron; Clemson University; Università di Pisa; Universite Paris 7- Denis Diderot; Istituto Nazionale di Fisica Nucleare, Roma; Università degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; NASA Goddard Space Flight Center; University of Maryland; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Kavli Institute for Particle Astrophysics and Cosmology; Università degli Studi di Torino; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Università degli Studi di Bari; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Università degli Studi di Perugia; Naval Research Laboratory; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Bologna; Alma Mater Studiorum Università di Bologna; Università degli Studi di Napoli Federico II; Università degli Studi di Udine; Hiroshima University; Erlangen Centre for Astroparticle Physics; Universite d'Orleans; Institut National des Sciences de l'Univers; Friedrich-Alexander-Universität Erlangen-Nürnberg; University Science Institute Reykjavik; The Royal Institute of Technology (KTH); Universitat Autònoma de Barcelona; Mahidol University; University of Denver; Max Planck Institut für Physik (Werner-Heisenberg-Institut); Osservatorio Astronomico di Trieste© 2017. The American Astronomical Society. All rights reserved. The detection of high-redshift (z > 3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. More importantly, high-redshift blazars tend to host massive black holes and can be used to constrain the space density of heavy black holes in the early universe. Here, we report the first detection with the Fermi-Large Area Telescope of five γ-ray-emitting blazars beyond z = 3.1, more distant than any blazars previously detected in γ-rays. Among these five objects, NVSS J151002+570243 is now the most distant known γ-ray-emitting blazar at z = 4.31. These objects have steeply falling γ-ray spectral energy distributions (SEDs), and those that have been observed in X-rays have a very hard X-ray spectrum, both typical of powerful blazars. Their Compton dominance (ratio of the inverse Compton to synchrotron peak luminosities) is also very large (>20). All of these properties place these objects among the most extreme members of the blazar population. Their optical spectra and the modeling of their optical-UV SEDs confirm that these objects harbor massive black holes (MBH ∼ 10 8-10 Mo ). We find that, at z ≈ 4, the space density of >109 Mo black holes hosted in radio-loud and radio-quiet active galactic nuclei are similar, implying that radio-loudness may play a key role in rapid black hole growth in the early universe.Publication Metadata only Inferred cosmic-ray spectrum from fermi large area telescope -Ray Observations of Eartha's Limb(2014-04-17) M. Ackermann; M. Ajello; A. Albert; A. Allafort; L. Baldini; G. Barbiellini; D. Bastieri; K. Bechtol; R. Bellazzini; R. D. Blandford; E. D. Bloom; E. Bonamente; E. Bottacini; A. Bouvier; T. J. Brandt; M. Brigida; P. Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; C. Cecchi; E. Charles; R. C.G. Chaves; A. Chekhtman; J. Chiang; G. Chiaro; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Cutini; M. Dalton; F. Dammando; A. De Angelis; F. De Palma; C. D. Dermer; S. W. Digel; L. Di Venere; E. Do Couto E Silva; P. S. Drell; A. Drlica-Wagner; C. Favuzzi; S. J. Fegan; E. C. Ferrara; W. B. Focke; A. Franckowiak; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; G. A. Gomez-Vargas; I. A. Grenier; J. E. Grove; S. Guiriec; M. Gustafsson; D. Hadasch; Y. Hanabata; A. K. Harding; M. Hayashida; K. Hayashi; J. W. Hewitt; D. Horan; X. Hou; R. E. Hughes; Y. Inoue; M. S. Jackson; T. Jogler; G. Jóhannesson; A. S. Johnson; T. Kamae; Deutsche Elektronen-Synchrotron; Space Sciences Laboratory at UC Berkeley; Kavli Institute for Particle Astrophysics and Cosmology; Istituto Nazionale di Fisica Nucleare, Roma; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Universita degli Studi di Padova; Universita degli Studi di Perugia; Santa Cruz Institute for Particle Physics; NASA Goddard Space Flight Center; Politecnico di Bari; Laboratoire Leprince-Ringuet; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Institut de Recherche sur les Lois Fondamentales de l'Univers; George Mason University, Fairfax Campus; Agenzia Spaziale Italiana; Osservatorio Astronomico di Roma; Laboratoire Univers et Particules de Montpellier; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; Kungl. Vetenskapsakademien; IN2P3 Institut National de Physique Nucleaire et de Physique des Particules; Istituto Di Radioastronomia, Bologna; Universita degli Studi di Udine; Naval Research Laboratory; Fermi National Accelerator Laboratory; Hiroshima University; Universidad Autonoma de Madrid; Université libre de Bruxelles (ULB); Medizinische Universitat Innsbruck; University of Tokyo; JAXA Institute of Space and Astronautical Science; Ohio State University; The Royal Institute of Technology (KTH); University Science Institute Reykjavik; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; University of Maryland; Mahidol UniversityRecent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the -ray emission from Earthas limb for an indirect measurement of the local spectrum of CR protons in the energy range 90GeV-6TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68±0.04 and 2.61±0.08 above 200GeV, respectively. © 2014 American Physical Society.Publication Metadata only A Search for Cosmic-Ray Proton Anisotropy with the Fermi Large Area Telescope(2019-09-20) The Fermi-Lat Collaboration; M. Ajello; L. Baldini; G. Barbiellini; D. Bastieri; K. Bechtol; R. Bellazzini; E. Bissaldi; R. D. Blandford; R. Bonino; E. Bottacini; T. J. Brandt; P. Bruel; S. Buson; R. A. Cameron; R. Caputo; E. Cavazzuti; S. Chen; G. Chiaro; S. Ciprini; J. Cohen-Tanugi; 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; L. Di Venere; A. Domínguez; S. J. Fegan; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Giglietto; F. Giordano; M. Giroletti; D. Green; I. A. Grenier; S. Guiriec; K. Hayashi; E. Hays; J. W. Hewitt; D. Horan; G. Jóhannesson; M. Kuss; L. Latronico; J. Li; I. Liodakis; F. Longo; F. Loparco; P. Lubrano; S. Maldera; A. Manfreda; G. Martí-Devesa; M. N. Mazziotta; M. Meehan; I. Mereu; M. Meyer; P. F. Michelson; N. Mirabal; W. Mitthumsiri; T. Mizuno; A. Morselli; M. Negro; E. Nuss; N. Omodei; M. Orienti; E. Orlando; V. S. Paliya; D. Paneque; M. Persic; M. Pesce-Rollins; 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; J. B. Thayer; D. F. Torres; E. Troja; J. Vandenbroucke; M. Yassine; S. Zimmer; Istituto Nazionale di Fisica Nucleare, Sezione di Trieste; Istituto Nazionale di Fisica Nucleare, Sezione di Perugia; Istituto Nazionale di Fisica Nucleare, Sezione di Bari; Istituto Nazionale di Fisica Nucleare, Sezione di Torino; Istituto Nazionale di Fisica Nucleare, Sezione di Pisa; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Laboratoire Univers et Particules de Montpellier; Universite Paris-Saclay; Laboratoire Leprince-Ringuet; Kavli Institute for Particle Astrophysics and Cosmology; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; NYCB Realtime Computing Inc.; University Science Institute Reykjavik; Institució Catalana de Recerca i Estudis Avançats; University of Wisconsin-Madison; Agenzia Spaziale Italiana; Hiroshima University; Deutsches Elektronen-Synchrotron (DESY); Osservatorio Astronomico di Trieste; Stockholms universitet; Alma Mater Studiorum Università di Bologna; Universidad Complutense de Madrid; Clemson University; University of Maryland, Baltimore County; Universitat Autònoma de Barcelona; Università degli Studi di Bari; Istituto Nazionale di Fisica Nucleare - INFN; University of Maryland; Purdue University Calumet; Università degli Studi di Trieste; Rheinisch-Westfälische Technische Hochschule Aachen; Mahidol University; Julius-Maximilians-Universität Würzburg; Istituto Di Radioastronomia, Bologna; Università degli Studi di Torino; Max-Planck-Institut für Physik (Werner-Heisenberg-Institut); Medizinische Universitat Innsbruck; NASA Goddard Space Flight Center; Université de Genève; The George Washington University; Università degli Studi di Perugia; Friedrich-Alexander-Universität Erlangen-Nürnberg; University of Johannesburg; Università degli Studi di Padova; Nagoya University; University of North Florida© 2019. The American Astronomical Society. All rights reserved. The Fermi Large Area Telescope (LAT) has amassed a large data set of primary cosmic-ray protons throughout its mission. In fact, it is the largest set of identified cosmic-ray protons ever collected at this energy. 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 R.A. and decl., while ground-based observations only measure the anisotropy in R.A. We present the results of the first-ever proton anisotropy search using Fermi LAT. The data set was collected over eight years 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 decl. dependence of the dipole to date. We measure a dipole amplitude δ = 3.9 ±1.5 ×10-4 with a p-value of 0.01 (pretrials) for protons with energy greater than 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% confidence level upper limit on the dipole amplitude is δ UL = 1.3 ×10-3 for protons with energy greater than 78 GeV and δ UL = 1.2 ×10-3 for protons with energy greater than 251 GeV.Publication Metadata only The Second Catalog of Flaring Gamma-Ray Sources from the Fermi All-sky Variability Analysis(2017-09-01) S. Abdollahi; M. Ackermann; M. Ajello; A. Albert; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; J. Becerra Gonzalez; R. Bellazzini; E. Bissaldi; R. D. Blandford; E. D. Bloom; R. Bonino; E. Bottacini; J. Bregeon; P. Bruel; R. Buehler; S. Buson; R. A. Cameron; M. Caragiulo; P. A. Caraveo; E. Cavazzuti; C. Cecchi; A. Chekhtman; C. C. Cheung; G. Chiaro; S. Ciprini; J. Conrad; D. Costantin; F. Costanza; S. Cutini; F. D'Ammando; F. De Palma; A. Desai; R. Desiante; S. W. Digel; N. Di Lalla; M. Di Mauro; L. Di Venere; B. Donaggio; P. S. Drell; 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; M. Giomi; F. Giordano; M. Giroletti; T. Glanzman; D. Green; I. A. Grenier; J. E. Grove; L. Guillemot; S. Guiriec; E. Hays; D. Horan; T. Jogler; G. Jóhannesson; A. S. Johnson; D. Kocevski; M. Kuss; G. La Mura; S. Larsson; L. Latronico; J. Li; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; Hiroshima University; Deutsche Elektronen-Synchrotron; Clemson University; Los Alamos National Laboratory; Università di Pisa; Universite Paris 7- Denis Diderot; Istituto Nazionale di Fisica Nucleare, Roma; Università degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Università degli Studi di Padova; NASA Goddard Space Flight Center; University of Maryland; Istituto Nazionale Di Fisica Nucleare, Sezione di Pisa; Kavli Institute for Particle Astrophysics and Cosmology; Università degli Studi di Torino; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Università degli Studi di Bari; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Università degli Studi di Perugia; George Mason University, Fairfax Campus; Naval Research Laboratory; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Bologna; Alma Mater Studiorum Università di Bologna; Università degli Studi di Napoli Federico II; Università degli Studi di Udine; Erlangen Centre for Astroparticle Physics; Universite d'Orleans; Institut National des Sciences de l'Univers; Friedrich-Alexander-Universität Erlangen-Nürnberg; University Science Institute Reykjavik; The Royal Institute of Technology (KTH); Universitat Autònoma de Barcelona; Mahidol University; Max Planck Institut für Physik (Werner-Heisenberg-Institut); Osservatorio Astronomico di Trieste© 2017. The American Astronomical Society. All rights reserved. We present the second catalog of flaring gamma-ray sources (2FAV) detected with the Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over the entire sky observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. With respect to the first FAVA catalog, this catalog benefits from a larger data set, the latest LAT data release (Pass 8), as well as from an improved analysis that includes likelihood techniques for a more precise localization of the transients. Applying this analysis to the first 7.4 years of Fermi observations, and in two separate energy bands 0.1-0.8 GeV and 0.8-300 GeV, a total of 4547 flares were detected with significance greater than 6σ(before trials), on the timescale of one week. Through spatial clustering of these flares, 518 variable gamma-ray sources were identified. Based on positional coincidence, likely counterparts have been found for 441 sources, mostly among the blazar class of active galactic nuclei. For 77 2FAV sources, no likely gamma-ray counterpart has been found. For each source in the catalog, we provide the time, location, and spectrum of each flaring episode. Studying the spectra of the flares, we observe a harder-when-brighter behavior for flares associated with blazars, with the exception of BL Lac flares detected in the low-energy band. The photon indexes of the flares are never significantly smaller than 1.5. For a leptonic model, and under the assumption of isotropy, this limit suggests that the spectrum of freshly accelerated electrons is never harder than P ∼ 2.Publication Metadata only The spectrum and morphology of the Fermi bubbles(2014-09-20) M. Ackermann; A. Albert; W. B. Atwood; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; R. Bellazzini; E. Bissaldi; R. D. Blandford; E. D. Bloom; E. Bottacini; T. J. Brandt; J. Bregeon; P. Bruel; R. Buehler; S. Buson; 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; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Cutini; F. D'Ammando; A. De Angelis; F. De Palma; C. D. Dermer; S. W. Digel; L. Di Venere; E. Do Couto E Silva; P. S. Drell; C. Favuzzi; E. C. Ferrara; W. B. Focke; A. Franckowiak; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; F. Giordano; M. Giroletti; G. Godfrey; G. A. Gomez-Vargas; I. A. Grenier; S. Guiriec; D. Hadasch; A. K. Harding; E. Hays; J. W. Hewitt; X. Hou; T. Jogler; G. Jóhannesson; A. S. Johnson; W. N. Johnson; T. Kamae; J. Kataoka; J. Knödlseder; D. Kocevski; M. Kuss; S. Larsson; L. Latronico; F. Longo; F. Loparco; M. N. Lovellette; Deutsche Elektronen-Synchrotron; Kavli Institute for Particle Astrophysics and Cosmology; Santa Cruz Institute for Particle Physics; Istituto Nazionale di Fisica Nucleare, Roma; Institut de Recherche sur les Lois Fondamentales de l'Univers; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Universita degli Studi di Padova; NASA Goddard Space Flight Center; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Universita degli Studi di Perugia; George Mason University, Fairfax Campus; Osservatorio Astronomico di Roma; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; Kungl. Vetenskapsakademien; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Universita di Bologna; Universita degli Studi di Udine; Naval Research Laboratory; Universita degli Studi di Bari; Hiroshima University; Pontificia Universidad Catolica de Chile; Medizinische Universitat Innsbruck; University of Maryland, Baltimore County; Centre d'Etudes Nucleaires de Bordeaux Gradignan; University Science Institute Reykjavik; Waseda University; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; Yale University; University of Maryland; Mahidol University; University of California, Irvine; University of Denver; Max Planck Institut fur Physik (Werner-Heisenberg-Institut)© 2014. The American Astronomical Society. All rights reserved. The Fermi bubbles are two large structures in the gamma-ray sky extending to 55° above and below the Galactic center. We analyze 50 months of Fermi Large Area Telescope data between 100 MeV and 500 GeV above 10° in Galactic latitude to derive the spectrum and morphology of the Fermi bubbles. We thoroughly explore the systematic uncertainties that arise when modeling the Galactic diffuse emission through two separate approaches. The gamma-ray spectrum is well described by either a log parabola or a power law with an exponential cutoff. We exclude a simple power law with more than 7σ significance. The power law with an exponential cutoff has an index of 1.9 ± 0.2 and a cutoff energy of 110 ± 50 GeV. We find that the gamma-ray luminosity of the bubbles is erg s-1. We confirm a significant enhancement of gamma-ray emission in the southeastern part of the bubbles, but we do not find significant evidence for a jet. No significant variation of the spectrum across the bubbles is detected. The width of the boundary of the bubbles is estimated to be deg. Both inverse Compton (IC) models and hadronic models including IC emission from secondary leptons fit the gamma-ray data well. In the IC scenario, synchrotron emission from the same population of electrons can also explain the WMAP and Planck microwave haze with a magnetic field between 5 and 20 μG.Publication Metadata only The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV(2015-01-20) 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; E. Bottacini; T. J. Brandt; J. Bregeon; P. Bruel; R. Buehler; S. Buson; 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; R. Claus; J. Cohen-Tanugi; J. Conrad; A. Cuoco; S. Cutini; F. D'Ammando; A. De Angelis; F. De Palma; C. D. Dermer; S. W. Digel; E. Do Couto E Silva; P. S. Drell; C. Favuzzi; E. C. Ferrara; W. B. Focke; A. Franckowiak; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; P. Giommi; F. Giordano; M. Giroletti; G. Godfrey; G. A. Gomez-Vargas; I. A. Grenier; S. Guiriec; M. Gustafsson; D. Hadasch; K. Hayashi; E. Hays; J. W. Hewitt; P. Ippoliti; T. Jogler; G. Jóhannesson; A. S. Johnson; W. N. Johnson; T. Kamae; J. Kataoka; J. Knödlseder; M. Kuss; S. Larsson; Deutsche Elektronen-Synchrotron; Clemson University; Kavli Institute for Particle Astrophysics and Cosmology; Santa Cruz Institute for Particle Physics; Istituto Nazionale di Fisica Nucleare, Roma; Institut de Recherche sur les Lois Fondamentales de l'Univers; Universita degli Studi di Trieste; Istituto Nazionale Di Fisica Nucleare, Sezione di Padova; Universita degli Studi di Padova; University of Chicago; NASA Goddard Space Flight Center; Laboratoire Univers et Particules de Montpellier; Laboratoire Leprince-Ringuet; Consorzio Interuniversitario per la Fisica Spaziale (CIFS); INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan; Agenzia Spaziale Italiana; Universita degli Studi di Perugia; George Mason University, Fairfax Campus; Osservatorio Astronomico di Roma; Stockholms universitet; Oskar Klein Centre for Cosmoparticle Physics; Kungl. Vetenskapsakademien; Universita degli Studi di Torino; Istituto Di Radioastronomia, Bologna; Alma Mater Studiorum Universita di Bologna; Universita degli Studi di Napoli Federico II; Naval Research Laboratory; Universita degli Studi di Bari; Hiroshima University; Pontificia Universidad Catolica de Chile; Université libre de Bruxelles (ULB); Medizinische Universitat Innsbruck; JAXA Institute of Space and Astronautical Science; University of Maryland, Baltimore County; University Science Institute Reykjavik; Waseda University; CNRS Centre National de la Recherche Scientifique; Universite de Toulouse; Instituto de Estudios Espaciales de Cataluna; The Royal Institute of Technology (KTH); Centre d'Etudes Nucleaires de Bordeaux Gradignan; Yale University; University of Maryland; Mahidol University; University of California, Irvine© 2015. The American Astronomical Society. All rights reserved. The γ-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse γ-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi ) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission (DGE), and a longer data accumulation of 50 months allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 ± 0.02 and a break energy of (279 ± 52) GeV using our baseline DGE model. The total intensity attributed to the IGRB is (7.2 ± 0.6) x 10-6 cm-2 s-1 sr-1 above 100 MeV, with an additional +15%/-30% systematic uncertainty due to the Galactic diffuse foregrounds.