Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

VERITAS Collaboration; H.E.S.S. Collaboration

Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

VERITAS Collaboration
, H.E.S.S. Collaboration

Physics

DESY
University of Potsdam
Columbia University
Dublin Institute for Advanced Studies
Max-Planck-Institut fur Kernphysik
Yerevan State University
Landessternwarte Heidelberg
Université Paris-Sud
University of Groningen
Laboratoire Leprince-Ringuet
University of Namibia
North-West University
University of Hamburg
Uniwersytet Jagielloński
University of the Free State
Université Paris Cité
Linnaeus University, Växjö
University of Witwatersrand
Humboldt Universität zu Berlin
University of Tübingen
Université PSL
Sorbonne Université
University of Oxford
University of Erlangen-Nuremberg
University of Warsaw
Université Savoie Mont Blanc
Instytut Fizyki Jadrowej PAN
Université Bordeaux
University of Adelaide
Université Montpellier 2
Aix Marseille Université
University of Innsbruck
Nicolaus Copernicus University
Rikkyo University
N. Copernicus Astronomical Center
University of Leicester
University of Amsterdam
Konan University
University of Tokyo
Systems Glycobiology Research Group
University of Alabama
DePauw University
The Bartol Research Institute
University of Utah
Harvard & Smithsonian
California Polytechnic State University, San Luis Obispo
Washington University in St. Louis
University of Minnesota
California State University, East Bay
Santa Cruz Institute for Particle Physics
Department of Chemistry
University of Maryland
NASA Goddard Space Flight Center
McGill University
University College Dublin
University of Iowa
University of Galway
Barnard College
Queen’s University
University of California, Los Angeles
South Campus
Purdue University
Indiana University-Purdue University Indianapolis
Iowa State University

Research output: Contribution to a Journal (Peer & Non Peer) › Conference article › peer-review

Abstract

We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2 degrees away from the best-fit position of the IceCube neutrino event 211208A. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV gamma-ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and highenergy components of the broadband spectral energy distribution, and the gamma-ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cut-off near 100 GeV. Both measurements provide strong constraints on leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed spectral energy distribution (SED). The existence of an external photon field in the source would instead explain the observed gamma-ray spectral cut-off in both leptonic and lepto-hadronic models, and it would allow a proton jet power that marginally agrees with the Eddington limit in the leptohadronic model. A numerical lepto-hadronic model with external target photons reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.

Original language	English
Article number	1470
Journal	Proceedings of Science
Volume	444
Publication status	Published - 27 Sep 2024
Event	38th International Cosmic Ray Conference, ICRC 2023 - Nagoya, Japan Duration: 26 Jul 2023 → 3 Aug 2023

Cite this

@article{a5ecd0669b0845d2a3ba844effbf6cc1,

title = "Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A",

abstract = "We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2 degrees away from the best-fit position of the IceCube neutrino event 211208A. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV gamma-ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and highenergy components of the broadband spectral energy distribution, and the gamma-ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cut-off near 100 GeV. Both measurements provide strong constraints on leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed spectral energy distribution (SED). The existence of an external photon field in the source would instead explain the observed gamma-ray spectral cut-off in both leptonic and lepto-hadronic models, and it would allow a proton jet power that marginally agrees with the Eddington limit in the leptohadronic model. A numerical lepto-hadronic model with external target photons reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.",

author = "\{VERITAS Collaboration\} and \{H.E.S.S. Collaboration\} and M. Pohl and K. Mori and F. Aharonian and \{Ait Benkhali\}, F. and A. Alkan and J. Aschersleben and H. Ashkar and M. Backes and A. Baktash and \{Barbosa Martins\}, V. and A. Barnacka and J. Barnard and R. Batzofin and Y. Becherini and G. Beck and D. Berge and K. Bernl{\"o}hr and B. Bi and M. B{\"o}ttcher and C. Boisson and J. Bolmont and \{de Bony de Lavergne\}, M. and J. Borowska and M. Bouyahiaoui and F. Bradascio and M. Breuhaus and R. Brose and A. Brown and F. Brun and B. Bruno and T. Bulik and C. Burger-Scheidlin and T. Bylund and F. Cangemi and S. Caroff and S. Casanova and R. Cecil and J. Celic and M. Cerruti and P. Chambery and T. Chand and S. Chandra and A. Chen and J. Chibueze and O. Chibueze and T. Collins and G. Cotter and P. Cristofari and \{Damascene Mbarubucyeye\}, J. and Davids, \{I. D.\} and J. Davies and \{de Jonge\}, L. and J. Devin and A. Djannati-Ata{\"i} and A. Dmytriiev and V. Doroshenko and L. Dreyer and \{Du Plessis\}, L. and K. Egberts and S. Einecke and Ernenwein, \{J. P.\} and S. Fegan and K. Feijen and \{Fichet de Clairfontaine\}, G. and G. Fontaine and F. Lott and M. F{\"u}{\ss}ling and S. Funk and S. Gabici and Gallant, \{Y. A.\} and S. Ghafourizadeh and G. Giavitto and L. Giunti and D. Glawion and Glicenstein, \{J. F.\} and J. Glombitza and P. Goswami and G. Grolleron and Grondin, \{M. H.\} and L. Haerer and S. Hattingh and M. Haupt and G. Hermann and Hinton, \{J. A.\} and W. Hofmann and Holch, \{T. L.\} and M. Holler and D. Horns and Zhiqiu Huang and A. Jaitly and M. Jamrozy and F. Jankowsky and A. Jardin-Blicq and V. Joshi and I. Jung-Richardt and E. Kasai and K. Katarzynski and H. Katjaita and D. Khangulyan and Lang, \{M. J.\}",

note = "Publisher Copyright: {\textcopyright} Copyright owned by the author(s) under the terms of the Creative Commons.; 38th International Cosmic Ray Conference, ICRC 2023 ; Conference date: 26-07-2023 Through 03-08-2023",

year = "2024",

month = sep,

day = "27",

language = "English",

volume = "444",

journal = "Proceedings of Science",

issn = "1824-8039",

publisher = "Sissa Medialab Srl",

}

TY - JOUR

T1 - Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

AU - VERITAS Collaboration

AU - H.E.S.S. Collaboration

AU - Pohl, M.

AU - Mori, K.

AU - Aharonian, F.

AU - Ait Benkhali, F.

AU - Alkan, A.

AU - Aschersleben, J.

AU - Ashkar, H.

AU - Backes, M.

AU - Baktash, A.

AU - Barbosa Martins, V.

AU - Barnacka, A.

AU - Barnard, J.

AU - Batzofin, R.

AU - Becherini, Y.

AU - Beck, G.

AU - Berge, D.

AU - Bernlöhr, K.

AU - Bi, B.

AU - Böttcher, M.

AU - Boisson, C.

AU - Bolmont, J.

AU - de Bony de Lavergne, M.

AU - Borowska, J.

AU - Bouyahiaoui, M.

AU - Bradascio, F.

AU - Breuhaus, M.

AU - Brose, R.

AU - Brown, A.

AU - Brun, F.

AU - Bruno, B.

AU - Bulik, T.

AU - Burger-Scheidlin, C.

AU - Bylund, T.

AU - Cangemi, F.

AU - Caroff, S.

AU - Casanova, S.

AU - Cecil, R.

AU - Celic, J.

AU - Cerruti, M.

AU - Chambery, P.

AU - Chand, T.

AU - Chandra, S.

AU - Chen, A.

AU - Chibueze, J.

AU - Chibueze, O.

AU - Collins, T.

AU - Cotter, G.

AU - Cristofari, P.

AU - Damascene Mbarubucyeye, J.

AU - Davids, I. D.

AU - Davies, J.

AU - de Jonge, L.

AU - Devin, J.

AU - Djannati-Ataï, A.

AU - Dmytriiev, A.

AU - Doroshenko, V.

AU - Dreyer, L.

AU - Du Plessis, L.

AU - Egberts, K.

AU - Einecke, S.

AU - Ernenwein, J. P.

AU - Fegan, S.

AU - Feijen, K.

AU - Fichet de Clairfontaine, G.

AU - Fontaine, G.

AU - Lott, F.

AU - Füßling, M.

AU - Funk, S.

AU - Gabici, S.

AU - Gallant, Y. A.

AU - Ghafourizadeh, S.

AU - Giavitto, G.

AU - Giunti, L.

AU - Glawion, D.

AU - Glicenstein, J. F.

AU - Glombitza, J.

AU - Goswami, P.

AU - Grolleron, G.

AU - Grondin, M. H.

AU - Haerer, L.

AU - Hattingh, S.

AU - Haupt, M.

AU - Hermann, G.

AU - Hinton, J. A.

AU - Hofmann, W.

AU - Holch, T. L.

AU - Holler, M.

AU - Horns, D.

AU - Huang, Zhiqiu

AU - Jaitly, A.

AU - Jamrozy, M.

AU - Jankowsky, F.

AU - Jardin-Blicq, A.

AU - Joshi, V.

AU - Jung-Richardt, I.

AU - Kasai, E.

AU - Katarzynski, K.

AU - Katjaita, H.

AU - Khangulyan, D.

AU - Lang, M. J.

PY - 2024/9/27

Y1 - 2024/9/27

N2 - We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2 degrees away from the best-fit position of the IceCube neutrino event 211208A. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV gamma-ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and highenergy components of the broadband spectral energy distribution, and the gamma-ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cut-off near 100 GeV. Both measurements provide strong constraints on leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed spectral energy distribution (SED). The existence of an external photon field in the source would instead explain the observed gamma-ray spectral cut-off in both leptonic and lepto-hadronic models, and it would allow a proton jet power that marginally agrees with the Eddington limit in the leptohadronic model. A numerical lepto-hadronic model with external target photons reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.

AB - We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2 degrees away from the best-fit position of the IceCube neutrino event 211208A. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV gamma-ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and highenergy components of the broadband spectral energy distribution, and the gamma-ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cut-off near 100 GeV. Both measurements provide strong constraints on leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed spectral energy distribution (SED). The existence of an external photon field in the source would instead explain the observed gamma-ray spectral cut-off in both leptonic and lepto-hadronic models, and it would allow a proton jet power that marginally agrees with the Eddington limit in the leptohadronic model. A numerical lepto-hadronic model with external target photons reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.

UR - https://www.scopus.com/pages/publications/85212270610

M3 - Conference article

AN - SCOPUS:85212270610

SN - 1824-8039

VL - 444

JO - Proceedings of Science

JF - Proceedings of Science

M1 - 1470

T2 - 38th International Cosmic Ray Conference, ICRC 2023

Y2 - 26 July 2023 through 3 August 2023

ER -

Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

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