We explore the possibility that the astrophysical neutrinos are produced in $pp$-interactions with a gas cloud near the source acting as a beam dump, which is sufficiently dense to significantly attenuate the associated gamma-ray flux through pair-production on this gas. In this way, such sources could potentially supply the astrophysical neutrino flux whilst avoiding the existing constraints on the non-blazar contribution to the extragalactic gamma-ray background. After defining our model, we implement a Monte Carlo simulation and apply this to different scenarios. First, we investigate a set of active galaxies which exhibit signs of obscuration. We find that, currently, the expected neutrino flux from these objects in our model is below the existing exclusion limits, but can already constrain the amount of protons accelerated in such sources. Second, we investigate the diffuse neutrino flux generated by a population of obscured sources. We find that such a population can indeed alleviate the tension with the extragalactic background light. We discuss the possibility that ultra-luminous infrared galaxies represent such a source class.
The recent discovery of high-energy cosmic neutrinos by the IceCube neutrino observatory opens up a new field in physics, the field of neutrino astronomy. Using the IceCube neutrino detector we plan to search for high-energy neutrinos emitted from Active Galactic Nuclei (AGN), since AGN are believed to be one of the most promising sources of the most energetic cosmic rays and hence of high-energy neutrinos. We discuss a specific type of AGN which we plan to investigate in more detail with data obtained by the IceCube observatory. The main properties of the AGN category in which we are interest…
Active Galactic Nuclei (AGN) are believed to be one of the main source candidates for the high-energy (TeV-PeV) cosmic neutrino flux recently discovered by the IceCube neutrino observatory. Nevertheless, several correlation studies between AGN and the cosmic neutrinos detected by IceCube show no significance. Therefore, in this article we consider a specific sub-class of AGN for which an increased neutrino production is expected. This sub-class contains AGN for which their high-energy jet is pointing toward Earth. Furthermore, we impose the condition that the jet is obscured by gas or dust sur…
Ultra-Luminous Infrared Galaxies (ULIRGs) are the most luminous objects in the infrared sky. With infrared luminosities exceeding $10^{12}$ solar luminosities, ULIRGs contain strong star formation regions which could power hadronic acceleration. Moreover, a significant fraction of ULIRGs have been found to host Active Galactic Nuclei, which could also be a source of hadronic acceleration. Furthermore, such high infrared luminosities indicate that large amounts of dust are present in these objects. In the presence of hadronic acceleration, this dust not only represents an excellent target for h…
High-energy neutrinos from shocked circumnuclear material around optically-bright and infrared-only tidal disruption events
Fermi National Accelerator Laboratory（费米国家加速器实验室）；University of Chicago（芝加哥大学）；NSF-Simons AI Institute for the Sky (SkAI)（NSF-西蒙斯天空人工智能研究所）；Tohoku University（东北大学）；The University of Tokyo（东京大学）
Correlation Between Hard X-Ray and Cosmic Neutrino Sources: From Obscured AGN to Blazars
ELTE Eötvös Loránd University（厄特沃什·罗兰大学）；HUN-REN Research Centre for Astronomy and Earth Sciences（匈牙利研究与教育网络地球科学与天文学研究中心）；Ruhr University Bochum（波鸿鲁尔大学）；University of Florida（佛罗里达大学）；University of Geneva（日内瓦大学）；Universidad Diego Portales（迭戈·波特莱斯大学）；Chalmers University of Technology（查尔姆斯理工大学）；University of Wisconsin, Madison（威斯康星大学麦迪逊分校）
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
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 coro…
High-Energy Neutrino Emission in NGC1068 driven by Turbulent Magnetic Reconnection
Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG-USP), Universidade de São Paulo（圣保罗大学地球物理与大气科学学院）；Centro Brasileiro de Pesquisas Físicas (CBPF)（巴西物理研究中心）
We study the possible indirect neutrino signal from dark matter annihilations inside the solar interior for relatively light dark matter masses in the O(10) GeV range. Due to their excellent energy reconstruction capabilities, we focus on the detection of this flux in liquid argon or magnetized iron calorimeter detectors, proposed for the next generation of far detectors of neutrino oscillation experiments and neutrino telescopes. The aim of the study is to probe the ability of these detectors to determine fundamental properties of the dark matter nature such as its mass or its relative annihi…
The IceCube neutrino telescope discovered PeV-energy neutrinos originating beyond our Galaxy with an energy flux that is comparable to that of GeV-energy gamma rays and EeV-energy cosmic rays. These neutrinos provide the only unobstructed view of the cosmic accelerators that power the highest energy radiation reaching us from the universe. We will review the results from IceCube's first decade of operations, emphasizing the measurement of the diffuse multiflavored neutrino flux from the universe and the identification of the supermassive black hole TXS 0506+056 as a source of cosmic neutrinos …
The diffuse flux of cosmic neutrinos has been measured by the IceCube Observatory from TeV to PeV energies. We show that an improved characterization of this flux at the lower energies, TeV and sub-TeV, reveals important information on the nature of the astrophysical neutrino sources in a model-independent way. Most significantly, it could confirm the present indications that neutrinos originate in cosmic environments that are optically thick to GeV-TeV $γ$-rays. This conclusion will become inevitable if a steeper or even uninterrupted neutrino power law is observed in the TeV region. In such …
We identify a previously untapped discovery channel for grand-unification monopoles, arising from their ability to catalyse the direct decay of protons into monoenergetic 459 MeV antineutrinos within the Sun. Previous analyses omit this possibility as it necessarily involves an electroweak suppression factor, and instead search for the unsuppressed 20-50 MeV neutrinos produced via two-stage proton decays. By accounting for the relative difference in interaction cross section and experimental background at typical neutrino detection experiments, we demonstrate that this new channel in fact poss…
Event spectra of the neutrino-$^{16}$O charged-current reactions in Super-Kamiokande are evaluated for a future supernova neutrino burst. Since these channels are expected to be useful for diagnosing a neutrino spectrum with high average energy, the evaluations are performed not only for an ordinary supernova neutrino model but also for a model of neutrino emission from a black-hole-forming collapse. Using shell model results, whose excitation energies are consistent with the experimental data, the cross sections of the $^{16}$O($ν_e, e^-$)X and $^{16}$O($\barν_e, e^+$)X reactions for each nuc…
One of the few remaining unknowns in the standard three-flavor neutrino oscillation paradigm is the ordering of neutrino masses. In this work we propose a novel method for determining neutrino mass ordering using the time information on early supernova neutrino events. In a core-collapse supernova, neutrinos are produced earlier than antineutrinos and, depending on the mass ordering which affects the adiabatic flavor evolution, may cause earlier observable signals in $ν_e$ detection channels than in others. Hence, the time differences are sensitive to the mass ordering. We find that using the …
Atmospheric muon neutrino in Deep Core (whose rate and spectra might be soon available) should exhibit a suppression (due to tens GeV up-going muon neutrino converted into tau flavor) that must be imprinted in out-coming rate spectra. We estimate here our independent muon neutrino spectra based on SK and its projected record on Deep Core Channels. Our estimate (based on cosmic rays, muon records and tested Super-Kamiokande (SK) data) differs both in shape and in rate from other previous published spectra. The expected rate might exhibit a minimum near channel 6 of Deep Core strings and it shou…
The IceCube Neutrino Observatory, which instruments 1$\,$km$^3$ of clear ice at the geographic South Pole, was mainly designed to detect particles with energies in the multi-GeV to PeV range. Due to ice temperatures between $-20^\circ$C to $-43^\circ$C and the low radioactivity of the ice, the dark noise rates of the 5160 photomultiplier tubes forming the IceCube lattice are of order 500 Hz, which is particularly low for 10 inch photomultipliers. Therefore, IceCube can extend its searches to bursts of $\mathcal{O}$(10$\,$MeV) neutrinos lasting several seconds, which are expected to be produced…
Self-annihilating dark matter gravitationally captured by the Sun could yield observable neutrino signals at current and next generation neutrino detectors. By exploiting such signals, neutrino detectors can probe the spin-dependent scattering of weakly interacting massive particles (WIMPs) with nucleons in the Sun. We describe a method how to convert constraints on neutrino fluxes to a limit on the WIMP-nucleon scattering cross section. In this method all neutrino flavors can be treated in a very similar way. We study the sensitivity of neutrino telescopes for Solar WIMP signals using vertex …
We explore the electron neutrino signals from light dark matter (DM) annihilation in the Sun for the large liquid scintillator detector JUNO. In terms of the spectrum features of three typical DM annihilation channels $χχ\rightarrow ν\barν,τ^+ τ^-, b \bar{b}$, we take two sets of selection conditions to calculate the expected signals and atmospheric neutrino backgrounds based on the Monte Carlo simulation data. Then the JUNO sensitivities to the spin independent DM-nucleon and spin dependent DM-proton cross sections are presented. It is found that the JUNO projected sensitivities are much bett…
A method to search for neutrino induced showers from gamma-ray bursts in the ANTARES detector is presented. ANTARES consists of a three-dimensional array of photosensitive devices that measure Cherenkov light induced by charged particles produced by high energy neutrinos interacting in the detector vicinity. The shower channel is complementary to the more commonly used upgoing muon channel. The corresponding detection volume is smaller, but has the advantage of being sensitive to neutrinos of any flavour.
We present a new method by which to retrieve energy spectrum for all flavor of neutrinos from core-collapse supernova (CCSN). In the retrieval process, we do not assume any analytic formulae to express the energy spectrum of neutrinos but rather take a direct way of spectrum reconstruction from the observed data; the Singular Value Decomposition algorithm with a newly developed adaptive energy-gridding technique is adopted. We employ three independent reaction channels having different flavor sensitivity to neutrinos. Two reaction channels, inverse beta decay on proton and elastic scattering o…
Neutrino emission due to the pair breaking and formation processes in the bulk triplet superfluid in neutron stars is investigated with taking into account of anomalous weak interactions. We consider the problem in the BCS approximation discarding Fermi-liquid effects. In this approach we derive self-consistent equations for anomalous vector and axial-vector vertices of weak interactions taking into account the $^{3}P_{2}- ^{3}F_{2}$ mixing. Further we simplify the problem and consider the pure $^{3}P_{2}$ pairing with $m_{j}=0$, as is adopted in the minimal cooling paradigm. As was expected b…
The progenitors of supernovae (SNe) type Ia are usually assumed to be either a single white dwarf (WD) accreting from a non-degenerate companion (the SD channel) or the result of two merging WDs (DD channel). However, no consensus currently exists as to which progenitor scenario is the correct one, or whether the observed SN Ia rate is produced by a combination of both channels. Unlike a DD progenitor a SD progenitor is expected to emit supersoft X-rays for a prolonged period of time (~1 Myr) as a result of the burning of accreted matter on the surface of the WD. An argument against the SD cha…
Assessing the Relative Importance of Neutrino Matter Interaction Channels in Post-Merger Remnant of Binary Neutron Stars
University of New Hampshire（新罕布什尔大学）；Cornell University（康奈尔大学）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；California Institute of Technology（加州理工学院）
The Surface Detector array of the Pierre Auger Observatory can detect neutrinos with energy between 10^17 eV and 10^20 eV from point-like sources across the sky south of +55 deg and north of -65 deg declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavours in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrinos interactions in the Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an …
In 2016, IceCube initiated a system of public real-time alerts that are typically issued within one minute, following the detection of a neutrino candidate event that is likely to be of astrophysical origin. The goal of these alerts is to enable multi-messenger observations that may identify the neutrino source. Through January 31, 2019, a total of 20 public alerts have been issued, with many of them receiving follow-up observations across multiple wavelength bands. One alert in particular, IceCube-170922A, was found to be associated with a flaring gamma-ray blazar, TXS 0506+056. This was the …
Astrophysical environments that reach temperatures greater than $\sim$ 100 keV can have significant neutrino energy loss via both plasma processes and nuclear weak interactions. We find that nuclear processes likely produce the highest-energy neutrinos. Among the important weak nuclear interactions are both charged current channels (electron capture/emission and positron capture/emission) and neutral current channels (de-excitation of nuclei via neutrino pair emission). We show that in order to make a realistic prediction of the nuclear neutrino spectrum, one must take nuclear structure into a…
Supernovae emit large fluxes of neutrinos which can be detected by detectors on Earth. Future tonne-scale detectors will be sensitive to several neutrino interaction channels, with thousands of events expected if a supernova emerges in the galaxy neighborhood. There is a limited number of tools to study the interaction rates of supernova neutrinos, although a plethora of available supernova models exists. EstrellaNueva is an open-source software to calculate expected rates of supernova neutrinos in detectors using target materials with typical compositions, and additional compositions can be e…
The Astrophysical Multimessenger Observatory Network (AMON), has developed a real-time multi-messenger alert system. The system performs coincidence analyses of datasets from gamma-ray and neutrino detectors, making the Neutrino-Electromagnetic (NuEM) alert channel. For these analyses, AMON takes advantage of sub-threshold events, i.e., events that by themselves are not significant in the individual detectors. The main purpose of this channel is to search for gamma-ray counterparts of neutrino events. We will describe the different analyses that make up this channel and present a selection of …
