Investigation of Two Fermi-LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube

S Garrappa,C Argüelles,J Kim,R Koirala,A Schneider,J Auffenberg,M Song,R W Moore,K Woschnagg,K Wiebe,E Blaufuss,F Tenholt,T Karg,N Park,M Börner,D Rysewyk,S De Ridder,R Hellauer,N Iovine,A Olivas,E Pinat,L Tomankova,T K Gaisser,T Deyoung,M Labare,J Lünemann,G Binder,X W Xu,C Rott,C De Clercq,T Kittler,A Keivani,J L Lanfranchi,M Günder,P Nakarmi,J Bourbeau,B Relethford,D Chirkin,K Hanson,J Becker Tjus,K Meagher,J F Beacom,R Hoffmann,S Westerhoff,S Benzvi,J P A M De André,S Toscano,T Glüsenkamp,T Stuttard,P B Price,J C Díaz-Vélez,G Yodh,T Palczewski,N Van Eijndhoven,K.-H Becker,J Kiryluk,P Peiffer,C S Kochanek,R Snihur,K Mallot,W Rhode,L Rauch,K Ghorbani,A O’Murchadha,A Ishihara,P A Evenson,M Santander,S Fahey,H Niederhausen,K Andeen,Z Griffith,M Vraeghe,A Stasik,Q R Liu,K Filimonov,K Satalecka,L Wille,S Hickford,J L Prieto,G M Spiczak,P Desiati,N Kulacz,X Bai,G C Hill,M Dunkman,V Baum,M Kowalski,A Franckowiak,C Chen,I Ansseau,D Seckel,T Ruhe,S Miarecki,K Krings,D V Pankova,A Wallace,G Maggi,D Heereman,F Lucarelli,S In,M Silva,A Turcati,K Clark,T Carver,L Köpke,J Stettner,G Krückl,T Meures,J L Kelley,G T Przybylski,K Helbing,P Eller,S Buson,R Maruyama,G Anton,D L Xu,R G Stokstad,S Sarkar,A Obertacke Pollmann,K D Hoffman,J Madsen,E Friedman,J Sandroos,J M Conrad,D Hebecker,N L Strotjohann,J Adams,K Hoshina,D Grant,K Leonard,J Wood,R Bay,A Goldschmidt,O Botner,E Jacobi,A Terliuk,T Menne,G De Wasseige,B J Whelan,J Gallagher,M Medici,K Mase,M Rameez,M Ahrens,A Kyriacou,S Seunarine,S C Nowicki,F Halzen,M Tselengidou,H Kolanoski,C Spiering,R Reimann,A Stößl,K Hultqvist,T R Wood,G W Sullivan,M Wallraff,S Vanheule,D Pieloth,C Walck,K Rawlins,S Bron,M Plum,K Z Stanek,J Stachurska,H.-P Bretz,R Cross,E Cheung,S W Barwick,H Bagherpour,M Ackermann,T B Watson,E Unger,D Tosi,D J Koskinen,T Stanev,B Eberhardt,L Halve,D Soldin,L Wills,S Kunwar,E Bernardini,D Ryckbosch,N Kurahashi,M Leuermann,D Van Eijk,M Sutherland,M Usner,M A Unland Elorrieta,D Berley,A Hallgren,M J Larson,N Whitehorn,F Huang,A Pizzuto,S Kopper,D F Cowen,M Wolf,A Fritz,R Nahnhauer,A Steuer,S Sclafani,S Böser,J A Aguilar,G Neer,M Stamatikos,Y Xu,D Bindig,G S Japaridze,S R Klein,C Kopper,U Katz,K Jero,A Kappes,A Sandrock,T Kintscher,A R Fazely,J Felde,C F Turley,M De With,T Stezelberger,N Wandkowsky,E Resconi,P Schlunder,M Ahlers,B J Shappee,A Burgman,D R Nygren,G Merino,S E Sanchez Herrera,C Wendt,R Maunu,M G Aartsen,G Momenté,M Kauer,T Montaruli,C Pérez De Los Heros,C Finley,S Tilav,B J P Jones,J Braun,B Hokanson-Fasig,J J Beatty,A Karle,M Richman,L Classen,L Gerhardt,W Van Driessche,J Hignight,I Taboada,J Vandenbroucke,T Schmidt,Hershal Pandya ,Matthew J Weiss ,Hrvoje Dujmović ,Bunheng Ty ,Roxanne Turcotte ,Paul Coppin ,Thomas Ehrhardt ,David Kappesser ,Daniel Williams ,Jessie Micallef ,Lisa Johanna Schumacher ,Christoph Raab ,Immacolata Carmen Rea ,Summer Blot ,Jannes Brostean-Kaiser ,D Besson ,Johannes Werthebach ,Maximilian Meier ,Pablo Correa ,T W S Holoien ,Marjon Moulai ,J G González ,Merlin Schaufel ,Todd A Thompson ,Lu Lu ,Uwe Naumann ,Ali Kheirandish ,Theo Glauch ,Judith Schneider ,M E Huber ,Kendall Mahn ,Raamis Hussain ,Anastasia Maria Barbano ,Andrés Medina ,Mirco Hünnefeld ,Chun Fai Tung ,Frederik Hermann Lauber ,Shigeru Yoshida ,Woosik Kang ,Ch Weaver ,Minjin Jeong ,Giovanni Renzi ,Amirreza Raissi ,Emily Dvorak ,Martina Karl ,James Delaunay ,Spencer Axani ,Gerrit Wrede ,Krijn De Vries ,Mehmet Gündüz ,Christoph Tönnis ,Tobias Hoinka ,Ryo Nagai ,Federica Bradascio ,Pranav Dave ,J P Yañez ,William Luszczak ,Sarah Mancina ,W G Anderson ,J V Santen ,Gabriel Collin ,Jan Weldert ,Felix Henningsen ,Subo Dong ,Christian Haack ,Sally Robertson ,Jeffrey Lazar ,Elisa Lohfink ,Ioana Codrina Maris ,Martin Rongen ,Kunal Deoskar ,C Böhm ,Etienne Bourbeau ,A Dı́az ,Stephan Meighen-Berger ,Erin O’sullivan ,H.-P Dembinski ,Jan Soedingrekso ,Ibrahim Safa ,S Ter–Antonyan ,Paul Backes ,Raffaela Busse ,Christopher Wiebusch ,Robert Stein ,Cyril Martin Alispach ,Erik Ganster ,Yuya Makino ,Tianlu Yuan

doi:10.3847/1538-4357/ab2ada

Abstract

Abstract After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria. We find one additional known gamma-ray source, the blazar GB6 J1040+0617, in spatial coincidence with a neutrino in this sample. The chance probability of this coincidence is 30% after trial correction. For the first time, we present a systematic study of the gamma-ray flux, spectral and optical variability, and multiwavelength behavior of GB6 J1040+0617 and compare it to TXS 0506+056. We find that TXS 0506+056 shows strong flux variability in the Fermi-Large Area Telescope gamma-ray band, being in an active state around the arrival of IceCube-170922A, but in a low state during the archival IceCube neutrino flare in 2014/15. In both cases the spectral shape is statistically compatible (≤2σ) with the average spectrum showing no indication of a significant relative increase of a high-energy component. While the association of GB6 J1040+0617 with the neutrino is consistent with background expectations, the source appears to be a plausible neutrino source candidate based on its energetics and multiwavelength features, namely a bright optical flare and modestly increased gamma-ray activity. Finding one or two neutrinos originating from gamma-ray blazars in the given sample of high-energy neutrinos is consistent with previously derived limits of neutrino emission from gamma-ray blazars, indicating the sources of the majority of cosmic high-energy neutrinos remain unknown.

Full Text