Recent multimessenger studies have provided evidence for high-energy neutrino sources that are opaque to GeV-TeV gamma rays. We present model-independent studies on the connection between neutrinos and gamma rays in the active galaxy NGC 1068, and find that the neutrinos most likely come from regions within about 30-100 Schwarzschild radii. This is especially the case if neutrinos are produced via the photomeson production process, although the constraints could be alleviated if hadronuclear interactions are dominant. We consider the most favorable neutrino production regions, and discuss coronae, jets, winds, and their interactions with dense material. The results strengthen the importance of understanding dissipation mechanisms near the coronal region and the outflow base. There could be a connection between active galactic nuclei with near-Eddington accretion and tidal disruptions events, in that neutrinos are produced in the obscured vicinity of supermassive black holes.
We propose a one-loop induced neutrino mass model with hidden $U(1)$ gauge symmetry, in which we successfully involve a bosonic dark matter (DM) candidate propagating inside a loop diagram in neutrino mass generation to explain the $e^+e^-$ excess recently reported by the DArk Matter Particle Explorer (DAMPE) experiment. In our scenario dark matter annihilates into four leptons through $Z'$ boson as DM DM $\to Z' Z' (Z' \to \ell^+ \ell^-)$ and $Z'$ decays into leptons via one-loop effect. We then investigate branching ratios of $Z'$ taking into account lepton flavor violations and neutrino osc…
Mysteries about the origin of high-energy cosmic neutrinos have deepened by the recent IceCube measurement of a large diffuse flux in the 10-100 TeV range. Based on the standard disk-corona picture of active galactic nuclei (AGN), we present a phenomenological model enabling us to systematically calculate the spectral sequence of multimessenger emission from the AGN coronae. We show that protons in the coronal plasma can be stochastically accelerated up to PeV energies by plasma turbulence, and find that the model explains the large diffuse flux of medium-energy neutrinos if the cosmic rays ca…
坍缩星可能是长伽马射线暴（lGRB）的前身。lGRB已经被观察到持续数千到数万秒，因此中微子驱动的发动机不太可能作为驱动喷流的主要机制。在这种情况下，布兰德福德Znajek机制似乎可以解释生产的旋转轴定向喷流，而不需要大吸积率。这些发动机，需要磁场之间的$10^{12}$ G $< B < 10^{15}$ G线程内磁盘，克尔BH区存在。本文导出了由电子、质子、中子及其反粒子组成的弱磁和强磁伽玛暴火球流中中微子的自能和有效势，最高可达O（1/ $M_W^4$）。我们考虑的中微子能量为1-100 MeV，产生于恒星坍缩，合并事件或在火球本身的电子正电子湮没，逆β衰变和核子韧致辐射过程。这些中微子中有许多会通过火球传播，并可能发生共振振荡。使用两个中微子混合，我们研究这些振荡的可能性。
A hidden ultra-relativistic spine in the jet of a neutrino-associated blazar
Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；Julius-Maximilians-Universität Würzburg（维尔茨堡朱利叶斯-马克西米利安大学）；Joint Institute for VLBI ERIC（甚长基线干涉测量联合研究所）；Department of Physics and Astronomy, Denison University（丹尼森大学物理与天文学系）；Black Hole Initiative, Harvard University（哈佛大学黑洞倡议项目）；GFZ Helmholtz Centre for Geosciences（GFZ赫尔姆霍兹地学研究中心）；Special Astrophysical Observatory of the Russian Academy of Sciences（俄罗斯科学院特别天体物理观测站）；Instituto de Astrofísica de Andalucía-CSIC（安达卢西亚天体物理学研究所-CSIC）；National Radio Astronomy Observatory（国家射电天文台）
Tidal disruption events (TDE) have been considered as cosmic-ray and neutrino sources for a decade. We suggest two classes of new scenarios for high-energy multi-messenger emission from TDEs that do not have to harbor powerful jets. First, we investigate high-energy neutrino and gamma-ray production in the core region of a supermassive black hole. In particular, we show that about 1-100 TeV neutrinos and MeV gamma-rays can efficiently be produced in hot coronae around an accretion disk. We also study the consequences of particle acceleration in radiatively inefficient accretion flows (RIAFs). …
Neutrinos from hidden ultraluminous X-ray sources in the Galaxy
Instituto Argentino de Radioastronomía (CCT La Plata, CONICET（阿根廷射电天文研究所）；CICPBA（拉普拉塔国立大学天文与地球物理学院）；UNLP)（马德普拉塔物理研究所）；Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata（马德普拉塔国立大学理学院物理系）；Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR – CONICET)；Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata
We study the reasonable requirements of two anomalous $U(1)$s in a flavored-axion framework for the anomaly cancellations of both $U(1)$-mixed gravity and $U(1)_Y\times[U(1)]^2$ which in turn determine the $U(1)_Y$ charges where $U(1)_Y$ is the hypercharge gauge symmetry of the standard model. We argue that, with a flavor symmetry group, axion-induced topology in symmetry-broken phases plays crucial roles in describing how quarks and leptons are organized at a fundamental level and make deep connections with each other. A unified model, as an example, is then proposed in a simple way to descri…
The origin of the IceCube neutrinos is still an open question. Upper limits from diffuse gamma-ray observations suggest that the neutrino sources are either distant or hidden from gamma-ray observations. It is possible that the neutrinos are produced in jets that are formed in the core-collapsing massive stars and fail to break out, the so-called choked jets. We study neutrinos from the jets choked in the hydrogen envelopes of red supergiant stars. Fast photo-meson cooling softens the neutrino spectrum, making it difficult to explain the PeV neutrinos observed by IceCube in a one-component sce…
Gamma-ray bursts (GRB) are the most intense electromagnetic (EM) sources in the Universe. Long GRB (LGRB) correspond to those events with a typical prompt emission of more than a few seconds. It is generally assumed that they are originated after an implosion of a very massive star within a central compact object engine that can be either a black hole (BH) or a rapidly-spinning highly-magnetized neutron star (NS). Nevertheless, one of the most challenging aspects of defining a unique model is that the progenitor remains initially hidden for direct EM observation. In this work, we investigate t…
