Search for Magnetically Broadened Cascade Emission from Blazars with VERITAS

S Archambault; A Archer; W Benbow; M Buchovecky; V Bugaev; M Cerruti; M. P Connolly; W Cui; A Falcone; M. Fernández Alonso; J. P Finley; H Fleischhack; L Fortson; A Furniss; S Griffin; M Hütten; O Hervet; J Holder; T. B Humensky; C. A Johnson; P Kaaret; P Kar; D Kieda; M Krause; F Krennrich; M. J Lang; T. T. Y Lin; G Maier; S McArthur; P Moriarty; D Nieto; S O'Brien; R. A Ong; A. N Otte; M Pohl; A Popkow; E Pueschel; J Quinn; K Ragan; P. T Reynolds; G. T Richards; E Roache; A. C Rovero; I Sadeh; K Shahinyan; D Staszak; I Telezhinsky; J Tyler; S. P Wakely; A Weinstein; T Weisgarber; P Wilcox; A Wilhelm; D. A Williams; B Zitzer

doi:10.3847/1538-4357/835/2/288

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Search for Magnetically Broadened Cascade Emission from Blazars with VERITAS

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Search for Magnetically Broadened Cascade Emission from Blazars with VERITAS

S Archambault, A Archer, W Benbow, M Buchovecky, V Bugaev, M Cerruti, M. P Connolly, W Cui, A Falcone, M. Fernández Alonso, …

The Astrophysical journal, Vol.835(2), p.288

02/02/2017

DOI: 10.3847/1538-4357/835/2/288

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https://doi.org/10.3847/1538-4357/835/2/288View

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Abstract

We present a search for magnetically broadened gamma-ray emission around active galactic nuclei (AGNs), using VERITAS observations of seven hard-spectrum blazars. A cascade process occurs when multi-TeV gamma-rays from an AGN interact with extragalactic background light (EBL) photons to produce electron-positron pairs, which then interact with cosmic microwave background photons via inverse-Compton scattering to produce gamma-rays. Due to the deflection of the electron-positron pairs, a non-zero intergalactic magnetic field (IGMF) would potentially produce detectable effects on the angular distribution of the cascade emission. In particular, an angular broadening compared to the unscattered emission could occur. Through non-detection of angularly broadened emission from 1ES 1218+304, the source with the largest predicted cascade fraction, we exclude a range of IGMF strengths around 10−14 G at the 95% confidence level. The extent of the exclusion range varies with the assumptions made about the intrinsic spectrum of 1ES 1218+304 and the EBL model used in the simulation of the cascade process. All of the sources are used to set limits on the flux due to extended emission.

BL Lacertae objects: general

galaxies: active

gamma rays: galaxies

magnetic fields

Details

Title: Subtitle: Search for Magnetically Broadened Cascade Emission from Blazars with VERITAS
Creators: S Archambault - McGill University
A Archer - Washington University in St. Louis
W Benbow - Harvard University
M Buchovecky - University of California, Los Angeles
V Bugaev - Washington University in St. Louis
M Cerruti - Harvard University
M. P Connolly - Ollscoil na Gaillimhe – University of Galway
W Cui - Purdue University West Lafayette
A Falcone - Pennsylvania State University
M. Fernández Alonso - Universidad de Buenos Aires
J. P Finley - Purdue University West Lafayette
H Fleischhack - DESY, Platanenallee 6, D-15738 Zeuthen, Germany
L Fortson - University of Minnesota
A Furniss - California State University, East Bay
S Griffin - McGill University
M Hütten - DESY, Platanenallee 6, D-15738 Zeuthen, Germany
O Hervet - University of California, Santa Cruz
J Holder - University of Delaware
T. B Humensky - Columbia University
C. A Johnson - University of California, Santa Cruz
P Kaaret - University of Iowa
P Kar - University of Utah
D Kieda - University of Utah
M Krause - DESY, Platanenallee 6, D-15738 Zeuthen, Germany
F Krennrich - Iowa State University
M. J Lang - Ollscoil na Gaillimhe – University of Galway
T. T. Y Lin - McGill University
G Maier - DESY, Platanenallee 6, D-15738 Zeuthen, Germany
S McArthur - Purdue University West Lafayette
P Moriarty - Ollscoil na Gaillimhe – University of Galway
D Nieto - Columbia University
S O'Brien - University College Dublin
R. A Ong - University of California, Los Angeles
A. N Otte - Georgia Institute of Technology
M Pohl - University of Potsdam
A Popkow - University of California, Los Angeles
E Pueschel - University College Dublin
J Quinn - University College Dublin
K Ragan - McGill University
P. T Reynolds - Cork Institute of Technology
G. T Richards - Georgia Institute of Technology
E Roache - Harvard University
A. C Rovero - Universidad de Buenos Aires
I Sadeh - DESY, Platanenallee 6, D-15738 Zeuthen, Germany
K Shahinyan - University of Minnesota
D Staszak - University of Chicago
I Telezhinsky - University of Potsdam
J Tyler - McGill University
S. P Wakely - University of Chicago
A Weinstein - Iowa State University
T Weisgarber - University of Wisconsin–Madison
P Wilcox - University of Iowa
A Wilhelm - University of Potsdam
D. A Williams - University of California, Santa Cruz
B Zitzer - McGill University
Resource Type: Journal article
Publication Details: The Astrophysical journal, Vol.835(2), p.288
DOI: 10.3847/1538-4357/835/2/288
ISSN: 0004-637X
eISSN: 1538-4357
Publisher: Institute of Physics (IOP)
Number of pages: 12
Language: English
Date published: 02/02/2017
Academic Unit: Physics and Astronomy
Record Identifier: 9984199745402771

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