The Second Catalog of Flaring Gamma-Ray Sources from the Fermi All-sky Variability Analysis

Abdollahi S, Ackermann M, Ajello M, Albert A, Baldini L, Ballet J, Barbiellini G, Bastieri D, Gonzalez JB, Bellazzini R, Bissaldi E, Blandford RD, Bloom ED, Bonino R, Bottacini E, Bregeon J, Bruel P, Buehler R, Buson S, Cameron RA, Caragiulo M, Caraveo PA, Cavazzuti E, Cecchi C, Chekhtman A, Cheung CC, Chiaro G, Ciprini S, Conrad J, Costantin D, Costanza F, Cutini S, D'Ammando F, De Palma F, Desai A, Desiante R, Digel SW, Di Lalla N, Di Mauro M, Di Venere L, Donaggio B, Drell PS, Favuzzi C, Fegan SJ, Ferrara EC, Focke WB, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giomi M, Giordano F, Giroletti M, Glanzman T, Green D, Grenier IA, Grove JE, Guillemot L, Guiriec S, Hays E, Horan D, Jogler T, Johannesson G, Johnson AS, Kocevski D, Kuss M, La Mura G, Larsson S, Latronico L, Li J, Longo F, Loparco F, Lovellette MN, Lubrano P, Magill JD, Maldera S, Manfreda A, Mayer M, Mazziotta MN, Michelson PF, Mitthumsiri W, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Negro M, Nuss E, Ohsugi T, Omodei N, Orienti M, Orlando E, Paliya VS, Paneque D, Perkins JS, Persic M, Pesce-Rollins M, Petrosian V, Piron F, Porter TA, Principe G, Raino S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Sgro C, Simone D, Siskind EJ, Spada F, Spandre G, Spinelli P, Stawarz L, Suson DJ, Takahashi M, Tanaka K, Thayer JB, Thompson DJ, Torres DF, Torresi E, Tosti G, Troja E, Vianello G, Wood KS (2017)

Publication Status: Published

Publication Type: Journal article

Publication year: 2017

Journal

Publisher: IOP PUBLISHING LTD

Book Volume: 846

Article Number: ARTN 34

Journal Issue: 1

DOI: 10.3847/1538-4357/aa8092

Abstract

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 6s (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 similar to 2.

Authors with CRIS profile

Involved external institutions

Stanford University United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) University of Padua / Universita degli Studi di Padova Italy (IT) National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) National Aeronautics and Space Administration (NASA) United States (USA) (US) École Polytechnique - Université Paris-Saclay France (FR) Deutsches Elektronen-Synchrotron DESY Germany (DE) AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum Sweden (SE) Hiroshima University Japan (JP) Clemson University United States (USA) (US) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) University of Pisa / Università di Pisa (UniPi) Italy (IT) Los Alamos National Laboratory United States (USA) (US) U.S. Naval Research Laboratory United States (USA) (US) George Mason University United States (USA) (US) University of Montpellier / Université Montpellier France (FR) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) University of Iceland (UI) / Háskóli Íslands Iceland (IS) Praxis, Inc. United States (USA) (US) Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics Germany (DE) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) Spain (ES) Purdue University Northwest / Purdue University Calumet United States (USA) (US) Jagiellonian University / Uniwersytet Jagielloński (UJ) Poland (PL) Mahidol University / มหาวิทยาลัยมหิดล Thailand (TH) University of Johannesburg South Africa (ZA) NYCB Real-Time Computing, Inc. United States (USA) (US) Stockholm University / Stockholms universitet Sweden (SE) University of Orléans / Université d'Orléans France (FR) University of Maryland United States (USA) (US)

How to cite

APA:

Abdollahi, S., Ackermann, M., Ajello, M., Albert, A., Baldini, L., Ballet, J.,... Wood, K.S. (2017). The Second Catalog of Flaring Gamma-Ray Sources from the Fermi All-sky Variability Analysis. Astrophysical Journal, 846(1). https://dx.doi.org/10.3847/1538-4357/aa8092

MLA:

Abdollahi, S., et al. "The Second Catalog of Flaring Gamma-Ray Sources from the Fermi All-sky Variability Analysis." Astrophysical Journal 846.1 (2017).

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