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 γ-rays, γ-flaring blazars do not have the opacity for protons to produce neutrinos. Here we present observational evidence for an alternative explanation, in which γ-ray emission is suppressed during efficient neutrino production. A large proton and target photon density helps produce neutrinos while temporarily suppressing the observable γ-emission due to a large γ γ opacity. We show that the Fermi-LAT γ-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 m 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 γ fluxes are correlated for both low and high states. This points to an active outflow that is γ-suppressed at the time of neutrino production. We find similar local γ-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 γ-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.

尽管在 2017 年发现高能中微子与耀变体 TXS 0506+056 的明显燃烧状态之间存在关联，但导致天体物理粒子加速和中微子产生的机制仍不确定。最近的研究发现，当对γ射线透明时，γ耀斑耀变体没有质子产生中微子的不透明度。在这里，我们提出了另一种解释的观察证据，其中在有效的中微子产生过程中抑制了γ射线发射。大量的质子和目标的光子密度有助于产生中微子，而暂时抑制观察到的γ -emission由于大量γ γ透明度。我们证明了 Fermi-LAT γ当 IceCube 记录到重合的高能中微子 IC-190730A 时，耀变体 PKS 1502+106 的通量处于局部最小值。使用来自 OVRO 40 m 望远镜的数据，我们发现在重合中微子 IC-190730A 的时间段内来自 PKS 1502+106 的无线电发射处于高状态，这与无线电和γ通量相关的早期时间段相反低状态和高状态。这指向在中微子产生时被γ抑制的主动流出。我们在其他耀变体中发现了类似的局部γ抑制，包括在同时检测到 IceCube 中微子时的 MAGIC TXS​​ 0506+056 的 TeV 通量和耀变体 PKS B1424-418 的 Fermi-LAT 通量。使用临时γ-抑制，中微子-耀变体巧合搜索可能比以前假设的要敏感得多，从而能够利用现有数据确定冰立方的弥散中微子通量的起源。