TY - JOUR
T1 - Photopion production in black-hole jets and flat-spectrum radio quasars as PeV neutrino sources
AU - Dermer, Charles D.
AU - Murase, Kohta
AU - Inoue, Yoshiyuki
N1 - Funding Information:
We wish to thank J. Becerra, E. Blaufuss, J. Finke, A. Kusenko, B. Lacki, B. Lott, A. Reimer, and K. Schatto for discussions and correspondence. We would like to acknowledge the very useful report of the referee, which helped clarify the issues surrounding this model. The work of C.D.D. is supported by the Chief of Naval Research . K.M. is supported by NASA through Hubble Fellowship, Grant No. 51310.01 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy , Inc., for NASA, under Contract No. NAS 5-26555 .
Publisher Copyright:
© 2014.
PY - 2014/9/1
Y1 - 2014/9/1
N2 - The IceCube Collaboration has reported neutrinos with energies between ~30 TeV and a few PeV that are significantly enhanced over the cosmic-ray induced atmospheric background. Viable high-energy neutrino sources must contain very high-energy and ultra-high-energy cosmic rays while efficiently making PeV neutrinos. Gamma-ray Bursts (GRBs) and blazars have been considered as candidate cosmic-ray accelerators. GRBs, including low-luminosity GRBs, can be efficient PeV neutrino emitters for low bulk Lorentz factor outflows, although the photopion production efficiency needs to be tuned to simultaneously explain ultra-high-energy cosmic rays. Photopion production efficiency of cosmic rays accelerated in the inner jets of flat spectrum radio quasars (FSRQs) is ~1-10% due to interactions with photons of the broad-line region (BLR), whereas BL Lac objects are not effective PeV neutrino sources due to the lack of external radiation fields. Photopion threshold effects with BLR photons suppress neutrino production below ~1 PeV, which implies that neutrinos from other sources would dominate over the diffuse neutrino intensity at sub-PeV energies. Reduction of the ≫ PeV neutrino flux can be expected when curving cosmic-ray proton distributions are employed. Considering a log-parabolic function to describe the cosmic-ray distribution, we discuss possible implications for particle acceleration in black-hole jets. Our results encourage a search for IceCube PeV neutrino events associated with γ-ray loud FSRQs using Fermi-LAT data. In our model, as found in our previous work, the neutrino flux is suppressed below 1 PeV, which can be tested with increased IceCube exposure.
AB - The IceCube Collaboration has reported neutrinos with energies between ~30 TeV and a few PeV that are significantly enhanced over the cosmic-ray induced atmospheric background. Viable high-energy neutrino sources must contain very high-energy and ultra-high-energy cosmic rays while efficiently making PeV neutrinos. Gamma-ray Bursts (GRBs) and blazars have been considered as candidate cosmic-ray accelerators. GRBs, including low-luminosity GRBs, can be efficient PeV neutrino emitters for low bulk Lorentz factor outflows, although the photopion production efficiency needs to be tuned to simultaneously explain ultra-high-energy cosmic rays. Photopion production efficiency of cosmic rays accelerated in the inner jets of flat spectrum radio quasars (FSRQs) is ~1-10% due to interactions with photons of the broad-line region (BLR), whereas BL Lac objects are not effective PeV neutrino sources due to the lack of external radiation fields. Photopion threshold effects with BLR photons suppress neutrino production below ~1 PeV, which implies that neutrinos from other sources would dominate over the diffuse neutrino intensity at sub-PeV energies. Reduction of the ≫ PeV neutrino flux can be expected when curving cosmic-ray proton distributions are employed. Considering a log-parabolic function to describe the cosmic-ray distribution, we discuss possible implications for particle acceleration in black-hole jets. Our results encourage a search for IceCube PeV neutrino events associated with γ-ray loud FSRQs using Fermi-LAT data. In our model, as found in our previous work, the neutrino flux is suppressed below 1 PeV, which can be tested with increased IceCube exposure.
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U2 - 10.1016/j.jheap.2014.09.001
DO - 10.1016/j.jheap.2014.09.001
M3 - Article
AN - SCOPUS:84911942837
SN - 2214-4048
VL - 3
SP - 29
EP - 40
JO - Journal of High Energy Astrophysics
JF - Journal of High Energy Astrophysics
ER -