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

Journal article

Publication Details

Author(s): 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
Journal: Astrophysical Journal
Publication year: 2017
Volume: 846
Journal issue: 1
ISSN: 0004-637X


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.

FAU Authors / FAU Editors

Funk, Stefan Prof. Dr.
Lehrstuhl für Physik
Jogler, Tobias Dr.
Lehrstuhl für Physik
Principe, Giacomo
Lehrstuhl für Physik

External institutions with authors

AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum
Clemson University
Deutsches Elektronen-Synchrotron DESY
École Polytechnique - Université Paris-Saclay
George Mason University
Hiroshima University
Italian Space Agency / Agenzia Spaziale Italiana (ASI)
Jagiellonian University / Uniwersytet Jagielloński (UJ)
Los Alamos National Laboratory
Mahidol University / มหาวิทยาลัยมหิดล
Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics
National Aeronautics and Space Administration (NASA)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN)
NYCB Real-Time Computing, Inc.
Praxis, Inc.
Purdue University Northwest / Purdue University Calumet
Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC)
Stanford University
Stockholm University / Stockholms universitet
University of Iceland (UI)
University of Johannesburg
University of Maryland
University of Montpellier / Université Montpellier
University of Orléans / Université d'Orléans
University of Padua
University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot
University of Pisa / Università di Pisa (UniPi)
U.S. Naval Research Laboratory

How to cite

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).

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


Last updated on 2019-18-07 at 08:53