Cosmic neutrinos from temporarily gamma-suppressed blazars

Abstract

Despite the uncovered association of a high-energy neutrino with the apparent flaring state of blazar TXS 0506+056 in 2017, the mechanisms leading to astrophysical particle acceleration and neutrino production are still uncertain. Recent studies found that when transparent to $\gamma$-rays, $\gamma$-flaring blazars do not have the opacity for protons to produce neutrinos. Here we present observational evidence for an alternative explanation, in which $\gamma$-ray emission is suppressed during efficient neutrino production. A large proton and target photon density help produce neutrinos while temporarily suppress the observable $\gamma$-emission due to a large $\gamma \gamma$ opacity. We show that the Fermi-LAT $\gamma$-flux of blazar PKS 1502+106 was at a local minimum when IceCube recorded the coincident high-energy neutrino IC-190730A. Using data from the OVRO 40-meter Telescope, we find that radio emission from PKS 1502+106 at the time period of the coincident neutrino IC-190730A was in a high state, in contrast to earlier time periods when radio and $\gamma$ fluxes are correlated for both low and high states. This points to an active outflow that is $\gamma$-suppressed at the time of neutrino production. We find similar local $\gamma$-suppression in other blazars, including in MAGIC's TeV flux of TXS\,0506+056 and Fermi-LAT's flux of blazar PKS B1424-418 at the time of coincident IceCube neutrino detections. Using temporary $\gamma$-suppression, neutrino-blazar coincidence searches could be substantially more sensitive than previously assumed, enabling the identification of the origin of IceCube's diffuse neutrino flux possibly with already existing data.

arXiv comment8 pages, 3 figures, accepted to ApJ Letters

References in corpus (35)

• Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector
• Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert
• The Spectral Energy Distribution of Fermi bright blazars
• First observation of PeV-energy neutrinos with IceCube
• On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
• Blazars in the Fermi Era: The OVRO 40-m Telescope Monitoring Program
• Semi-analytic modeling of the EBL and consequences for extragalactic gamma-ray spectra
• Time-integrated Neutrino Source Searches with 10 years of IceCube Data
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• Hidden Cosmic-Ray Accelerators as an Origin of TeV-PeV Cosmic Neutrinos
• Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event
• The blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic ray acceleration
• Klein-Nishina Effects in the Spectra of Non-Thermal Sources Immersed in External Radiation Fields
• Modelling the coincident observation of a high-energy neutrino and a bright blazar flare
• Blazar Flares as an Origin of High-Energy Cosmic Neutrinos?
• Swift X-ray Telescope Monitoring of Fermi-LAT Gamma Ray Sources of Interest
• Leptohadronic blazar models applied to the 2014-15 flare of TXS 0506+056
• Gamma-ray flares from red giant/jet interactions in AGN
• Dissecting the regions around IceCube high-energy neutrinos: growing evidence for the blazar connection
• Opening a New Window onto the Universe with IceCube
• Investigation of two Fermi-LAT gamma-ray blazars coincident with high-energy neutrinos detected by IceCube
• The long-lasting activity of 3C 454.3. GASP-WEBT and satellite observations in 2008-2010
• High-Energy Multi-Messenger Transient Astrophysics
• Patterns in the multi-wavelength behavior of candidate neutrino blazars
• Searching for Correlations in Simultaneous X-ray and UV Emission in the Narrow-line Seyfert 1 galaxy 1H 0707-495
• PKS 1502+106: A high-redshift Fermi blazar at extreme angular resolution. Structural dynamics with VLBI imaging up to 86 GHz
• On the Neutrino Flares from the Direction of TXS 0506+056
• VLBI radio structure and radio brightening of the high-energy neutrino emitting blazar TXS 0506+056
• Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056
• A ring accelerator? Unusual jet dynamics in the IceCube candidate PKS 1502+106
• Optical Observations Reveal Strong Evidence for High Energy Neutrino Progenitor
• Fermi-LAT counterparts of IceCube neutrinos above 100 TeV
• On the relative importance of hadronic emission processes along the jet axis of Active Galactic Nuclei
• Limitations on the Photo-disintegration Process as a Source of VHE Photons
• Photon and neutrino emission from active galactic nuclei

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• The Observation of High-Energy Neutrinos from the Cosmos: Lessons Learned for Multimessenger Astronomy
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• Time-integrated constraint on neutrino flux of CHIME fast radio burst sources with 10-year IceCube point-source data
• Evidence of a lepto-hadronic two-zone emission in flare states
• Multi-messenger emission from the parsec-scale jet of the flat-spectrum radio quasar PKS 1502+106 coincident with high-energy neutrino IceCube-190730A
• The IceCube Pie Chart: Relative Source Contributions to the Cosmic Neutrino Flux
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