Astrophysical neutrinos can be produced in proton interactions of charged cosmic rays with ambient photon or baryonic fields. Cosmic rays are observed in balloon, satellite and air shower experiments every day, from below 1e9 eV up to macroscopic energies of 1e21 eV. The observation of different photon fields has been done ever since, today with detections ranging from radio wavelengths up to very high-energy photons in the TeV range. The leading question for neutrino astronomers is now which sources provide a combination of efficient proton acceleration with sufficiently high photon fields or baryonic targets at the same time in order to produce a neutrino flux that is high enough to exceed the background of atmospheric neutrinos. There are only two confirmed astrophysical neutrino sources up to today: the sun and SuperNova 1987A emit and emitted neutrinos at MeV energies. The aim of large underground Cherenkov telescopes like IceCube and KM3NeT is the detection of neutrinos at energies above 100 GeV. In this paper, recent developments of neutrino flux modeling for the most promising extragalactic sources, gamma ray bursts and active galactic nuclei, are presented.
This is a (very) personal attempt to summarize the status of neutrino astronomy: its scientific motivations, our understanding of natural water and ice as particle detectors and, finally, the detector technology.
This paper presents a summary of the status of the field of very high-energy (VHE) gamma-ray astronomy, as of early 2006. The paper is based on the Rapporteur Talk given at the 29th International Cosmic Ray Conference in Pune, India (ICRC 2005). It covers astrophysical results from observations made by high-energy and very high-energy telescopes operating at photon energies above 1 GeV. The majority of recent observations in this field have been made by ground-based telescopes using the atmospheric Cherenkov or air shower techniques.
This paper summarizes the status of very high-energy (VHE) astronomy, as of early 2003. It concentrates on observations made by gamma-ray telescopes operating at energies above 10 GeV. This field is an exciting one to be working in, with a growing and varied list of established sources that includes plerions, supernova remnants, and active galactic nuclei. New results include the discovery of the first unidentified source at these energies and the detection of gamma rays from a nearby starburst galaxy (NGC 253). The arrival of a new generation of telescopes, both on the ground and in space, ar…
Neutrino astronomy offers the prospect to be able to look into the interior of compact astrophysical objects which may be the sources of cosmic radiation. This paper describes the results on neutrino observations from the sun and the supernova SN1987A along with an outlook on neutrino astronomy beyond the TeV scale.
In recent years, ground-based gamma-ray observatories have made a number of important astrophysical discoveries which have attracted the attention of the wider scientific community. The Division of Astrophysics of the American Physical Society has requested the preparation of a white paper on the status and future of ground-based gamma-ray astronomy to define the science goals of the future observatory, to determine the performance specifications, and to identify the areas of necessary technology development. In this contribution we give a brief overview of the activities of the current white …
1. Overview of neutrino astronomy: multidisciplinary science. 2. Cosmic accelerators: the highest energy cosmic rays. 3. Neutrino beam dumps: supermassive black holes and gamma ray bursts. 4. Neutrino telescopes: water and ice. 5. Indirect dark matter detection. 6. Towards kilometer-scale detectors.
This is a report on the findings of the Galactic compact objects working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper is an APS commissioned document, and the full version has also been released and can be found on astro-ph. This section of the white paper discusses the potential of future ground-based gamma-ray experiments to advance our understanding of the physics of Galactic compact objects including pulsars, pulsar wind nebulae, and X-ray binaries.
We report the status of the HAXTEL project, devoted to perform a design study and the development of a Laue lens prototype. After a summary of the major results of the design study, the approach adopted to develop a Demonstration Model of a Laue lens is discussed, the set up described, and some results presented.
This is a report on the findings of the technology working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses different technology opportunities and the technical feasibility for substantially improving IACTS and ground based particle detectors to achieve an order of magnitude better sensitivity than the instruments employed today as well as their planned upgrades. A technology roadmap for im…
The short review of theoretical aspects of ultra high energy (UHE) neutrinos and superGZK neutrinos. The sources and diffuse fluxes of UHE neutrinos are discussed. Much attention is given to comparison of the cascade and cosmic ray upper bounds for diffuse neutrino fluxes. Cosmogenic neutrinos and neutrinos from the mirror mater are considered as superGZK neutrinos.
This is a review of high energy neutrino astronomy that might be done with a kilometer-scale detector. The emphasis is on diffuse neutrinos of extragalactic origin and their relation to possible sources of the highest energy cosmic rays, such as active galaxies, cosmological gamma-ray burst sources and topological defects.
AMANDA (Antarctic Muon And Neutrino Detector Array) is a neutrino telescope built under the southern polar icecap, and its scope is exploring the possibility to detect high energy cosmic neutrinos generated by powerful celestial objects where acceleration mechanisms can bring protons up to 10^20 eV. We describe the achievements and results from the AMANDA-B10 prototype and the preliminary results from the current AMANDA-II detector showing a dramatic increase in sensitivity. An outlook on IceCube will be given.
Neutrinos may offer a unique opportunity to explore the far Universe at high energy. The ANTARES collaboration aims at building a large undersea neutrino detector able to observe astrophysical sources (AGNs, X-ray binary systems, ...) and to study particle physics topics (neutrino oscillation, ...). After a description of the research opportunities of such a detector, a status report of the experiment will be made.
The Super-Kamiokande experiment has collected a large sample of high-energy neutrino events. These are primarily atmospheric neutrinos, but a bright enough astrophysical source could also be visible. The data have been examined for possible point and bursting neutrino sources, as well as possible WIMP annihilation signatures. No significant evidence for such sources have been found, and the resulting flux limits have been calculated.
Very-high-energy astronomy studies the Universe at energies between 30 GeV and 100 TeV. The past decade has seen enormous progress in this field. There are now at least seven known sources of VHE photons. By studying these objects in the VHE regime one can begin to understand the environments surrounding these objects, and how particle acceleration is realized in nature. In addition the photon beams from the extragalactic gamma-ray sources can be used to study the electromagnetic fields in the intervening space. This recent progress can be traced to the development of a new class of detector w…
Data obtained in the very high energy gamma-ray band with the new generation of imaging telescopes, in particular through the galactic plane survey undertaken by H.E.S.S., low threshold observations with MAGIC and more recently by operation of VERITAS, have revealed dozens of galactic and extragalactic sources, providing a wealth of information on a variety of high energy acceleration sites in our universe. Also, the water Cherenkov instrument Milagro has provided several extended sources after seven years of data integration. An overview of these results with focus on some of the most recent …
The year 2008 has witnessed remarkable steps in developing high energy neutrino telescopes. IceCube at the South Pole has been deployed with 40 of its planned 80 strings and reached half a cubic kilometer instrumented volume, in the Mediterranean Sea the "first-stage" neutrino telescope ANTARES has been completed and takes data with 12 strings. The next years will be key years for opening the neutrino window to the high energy universe. IceCube is presently entering a region with realistic discovery potential. Early discoveries (or non-discoveries) with IceCube will strongly influence the desi…
Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of 10^{20} and 10^{13} eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of th…
The study of extragalactic sources of high energy radiation via the direct measurement of the proton and neutrino fluxes that they are likely to emit is one of the main goals for the future observations of the recently developed air showers detectors and neutrino telescopes. In this work we discuss the relation between the inclusive proton and neutrino signals from the ensemble of all sources in the universe, and the resolved signals from the closest and brightest objects. We also compare the sensitivities of proton and neutrino telescopes and comment on the relation between these two new astr…
This is a report on the findings of the gamma ray burst working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe gamma ray bursts at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to observe the highest energy emission ever recorded for GRBs, particularly for those that are nearby and have hig…
This is a report on the findings of the dark matter science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found on astro-ph (arXiv:0810.0444). This detailed section discusses the prospects for dark matter detection with future gamma-ray experiments, and the complementarity of gamma-ray measurements with other indirect, direct or accelerator-based searches. We conclude that any comprehensive search for dark matter should include gamma-ray observations, both…
Since the early 1990s, the South Pole has been the site of the construction of the world's first under-ice Cherenkov neutrino telescopes - AMANDA and IceCube. The AMANDA detector was completed in 2000, and its successor IceCube, a kilometre scale neutrino detector, began construction in 2005. Completion of IceCube is scheduled for 2011. This paper will give an overview of the history, construction, latest physics results and potential of these detectors.
Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of $10^{20}$ and $10^{13}$ eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results o…
Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of 10^{20} and 10^{13} eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of th…
Several of the models for origin of the highest energy cosmic rays also predict significant neutrino fluxes. A common factor of the models is that they must provide sufficient power to supply the observed energy in the extragalactic component of the cosmic radiation. The assumption that a comparable amount of energy goes into high-energy neutrinos allows a model-independent estimate of the neutrino signal that may be expected.
Nature produces cosmic ray particles, probably protons, with energies well above $10^{20}$ eV -- how are they produced? Where do they come from? Gamma rays with energies above $10^{13}$ eV are produced in jets of active galaxies -- are these produced by energetic electrons or protons? What is the correct model of Gamma Ray Bursts? These are just some of the fundamental questions in high energy astrophysics to be answered by observations made with large area neutrino telescopes.
This is a report on the findings of the extragalactic science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found on astro-ph (arXiv:0810.0444). This detailed section discusses extragalactic science topics including active galactic nuclei, cosmic ray acceleration in galaxies, galaxy clusters and large scale structure formation shocks, and the study of the extragalactic infrared and optical background radiation. The scientific potential of ground based gamm…
High energy gamma ray astronomy is now a well established field and several sources have been discovered in the region from a few GeV up to several TeV. If sources involving hadronic processes exist, the production of photons would be accompanied by neutrinos too. Other possible neutrino sources could be related to the annihilation of WIMPs at the center of galaxies with black holes. We present the results of a search for point-like sources using 1100 upward-going muons produced by neutrino interactions in the rock below and inside the MACRO detector in the underground Gran Sasso Laboratory. T…
AMANDA-II is the largest neutrino telescope collecting data at the moment, and its main goal is to search for sources of high energy extra-terrestrial neutrinos. The detection of such sources could give non-controversial evidence for the acceleration of charged hadrons in cosmic objects like Supernova Remnants, Micro-quasars, Active Galactic Nuclei or Gamma Ray Bursts. No significant excess has been found in searching for neutrinos from both point-like and non-localized sources. However AMANDA-II has significantly improved analysis techniques for better signal-to-noise optimization. The km$^3$…
This is a report on the findings of the SNR/cosmic-ray working group for the white paper on the status and future of ground-based gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe shell-type supernova remnants and diffuse emission from cosmic rays at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to study the acceleration of relativistic charged parti…
Although cosmic rays were discovered a century ago, we do not know where or how they are accelerated. There is a realistic hope that the oldest problem in astronomy will be solved soon by ambitious experimentation: air shower arrays of 10,000 kilometer-square area, arrays of air Cerenkov telescopes and kilometer- scale neutrino observatories. Their predecessors are producing science. We will review the highlights: - Cosmic rays: the highest energy particles and the GZK cutoff, the search for cosmic accelerators and the the Cygnus region, top-down mechanisms: photons versus protons? - TeV-energ…
The next ten years promise to be a particularly exciting decade for high energy neutrino astrophysics. The frontier of TeV and PeV energy is presently being tackled by large, expandable arrays constructed in open water or ice. Detectors tailored to record acoustic, radio, fluorescence or air shower signatures from neutrino interactions at PeV-EeV energy are being designed in parallel. During the next decade, the sensitivity to neutrinos from TeV to EeV energies may improve by 2 to 3 orders of magnitude. This talk reviews methods, status and prospects of detectors and sketches a scenario for th…
This work discusses the perspectives to observe fluxes of high energy astrophysical neutrinos with the planned km3 telescopes. On the basis of the observations of GeV and TeV gamma-rays, and of ultra high energy cosmic rays, it is possible to construct well motivated predictions that indicate that the discovery of such fluxes is probable. However the range of these predictions is broad, and the very important opening of the ``neutrino window'' on the high energy universe is not guaranteed with the current design of the detectors. The problem of enlarging the detector acceptance using the same …
Ultra High Energy, UHE, Neutrino Astronomy should be soon tested looking toward the Earth. At present High Energy Neutrino Astronomy is searched by AMANDA, ANTARES underground detectors looking for its consequent unique muons secondary track. We suggest a higher energy Tau Neutrino Astronomy based on Horizontal and Upward Tau Air-Showers escaping from the Earth. These Tau air-showers greatly amplifies the single tau track by an abundant secondary tail (billions of electron pairs, gamma and tens of millions muon bundles) spread in huge areas (kilometer size) easily observable (even partially) f…
Ultra High Energy (UHE) neutrino Astronomy and relic Neutrino masses may play a key role in solving the Ultra High Energy Cosmic Ray (UHECR) puzzle within the Z-Showering model. Tau air-shower originated by UHE neutrino in matter may probe and amplify this expected UHE neutrino Astronomy. The discover of upcoming and horizontal tau air-showers (UPTAUs, HORTAUs), born by UHE, nu_tau interacting inside mount chains or along Earth Crust crown masses at the Horizons edges, will greatly amplify the single UHE nu_tau track. Observing UPTAUs and HORTAUs along their line of showering, from higher ball…
By basing on observations of skeletal structures of the Sun and assuming that some of them are located inside of star, and also that a filamentary (linear) matter (whose a model earlier was put forward by B.U. Rodionov) is in basis of these internal structures the author consider possible processes of images formation of these structures inside the Sun and theirs coming out into space and also gives an elementary estimations of its parameters, which allow: i) to form their images in a flux of electronic neutrinos; ii) to carry out these images from within of the Sun into space; iii) to develop…
The high energy neutrino telescope NT200+ is currently in operation in Lake Baikal. We review the status of the Baikal the Baikal Neutrino Telescope, and describe recent progress on key components of the next generation kilometer-cube (km3) Lake Baikal detector, like investigation of new large area phototubes, integrated into the telescope.
The IceCube Observatory is a km^3 neutrino telescope currently under construction at the geographic South Pole. It will comprise 4800 optical sensors deployed on 80 vertical strings between 1450 and 2450 meters under the ice surface. Currently IceCube is operational and recording data with 40 strings (i.e. 2400 optical sensors). The IceCube Observatory will collect an unprecedented number of high energy neutrinos that will allow us to pursue studies of the atmospheric neutrino flux, and to search for extraterrestrial sources of neutrinos, whether point-like or unresolved. IceCube results will …
This is a short report on the preliminary findings of the gamma ray burst (GRB) working group for the white paper on the status and future of very high energy (VHE; >50 GeV) gamma-ray astronomy. The white paper discusses the status of past and current attempts to observe GRBs at GeV-TeV energies, including a handful of low-significance, possible detections. The white paper concentrates on the potential of future ground-based gamma-ray experiments to observe the highest energy emission ever recorded for GRBs, particularly for those that are nearby and have high Lorentz factors in the GRB jet. I…
The Earth's Shadow to Cosmic Rays offer a windows to Tau Neutrino Astronomy at the Horizon edges. Inclined and Horizontal C.R. Showers (70^o-90^o zenith angle) produce secondary (gamma,e) mostly suppressed by high column atmosphere depth. The shower Cherenkov photons are diluted and filtered by air opacity, but secondary penetrating, muon pairs and their decay into electron pairs, revive additional Cerenkov flash lights. Most largest GeVs gamma telescopes may detect such UHECR horizontal showers. Arrival angle and column depth, shower shape, timing may inform on the altitude interaction and on…
We review the present status of the Baikal Neutrino Project and present results on upward going atmospheric neutrinos, results of a search for high energy extraterrestrial neutrinos as well as preliminary results of searching for acoustic signals from EAS in water. We describe the moderate upgrade of NT-200 planned for next years and discuss a possible detector on the Gigaton scale.
We review the present status of the Baikal Neutrino Project and present preliminary results of a search for upward going atmospheric neutrinos, WIMPs and magnetic monopoles obtained with the detector NT-2000 during 1998. Also the results of a search for very high energy neutrinos with partially completed detector in 1996 are presented.
We consider the production of high energy neutrinos and cosmic rays in radio-quiet active galactic nuclei (AGN) or in the central regions of radio-loud AGN. We use a model in which acceleration of protons takes place at a shock in an accretion flow onto a supermassive black hole, and follow the cascade that results from interactions of the accelerated protons in the AGN environment. We use our results to estimate the diffuse high energy neutrino intensity and cosmic ray intensity due to AGN. We discuss our results in the context of high energy neutrino telescopes under construction, and measur…
We review the present status of the Baikal Underwater Neutrino Experiment and present results obtained with the various stages of the stepwise increasing detector: NT-36 (1993-95), NT-72 (1995-96) and NT-96 (1996-97). Results cover atmospheric muons, first clear neutrino events, search for neutrinos from WIMP annihilation in the center of the Earth, search for magnetic monopoles, and -- far from astroparticle physics -- limnology.
IceCube is currently being built deep in the glacial ice beneath the South Pole. In its second year of construction, it is already larger than its predecessor, AMANDA. AMANDA continues to collect high energy neutrino and muon data as an independent detector until it is integrated with IceCube. After introducing both detectors, recent results from AMANDA and a status report on IceCube are presented.
An overview is given of high-energy gamma-ray and neutrino astronomy, emphasizing the links between the two fields. With several new large detectors just becoming operational, the TeV gamma-ray and neutrino sky will soon be surveyed with unprecedented sensitivity.
Of all high-energy particles, only neutrinos can directly convey astronomical information from the edge of the universe---and from deep inside the most cataclysmic high-energy processes. Copiously produced in high-energy collisions, travelling at the velocity of light, and not deflected by magnetic fields, neutrinos meet the basic requirements for astronomy. Their unique advantage arises from a fundamental property: they are affected only by the weakest of nature's forces (but for gravity) and are therefore essentially unabsorbed as they travel cosmological distances between their origin and u…
Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and partile physics, cosmology and astronomy. Examples of their multidisciplinary mission include the search for the particle nature of dark matter and for additional small dimensions of space. In these lectures, we discuss the nature of cosmic neutrinos and their sources, the need for kilometer-scale detectors and the status and methodologies of current detectors.
We review the present status of the Baikal Deep Underwater Neutrino Experiment. The construction and performance of the large deep underwater Cherenkov detector for muons and neutrinos, NT-200 (Neutrino Telescope with 200 phototubes), which is currently under construction in Lake Baikal are described. Some results obtained with the intermediate detectors NT-36 (1993-95), NT-72 (1995-96) and NT-96 (1996-97) are presented, including the first clear neutrino candidates selected with 1994 and 1996 data.
In this article, based on the talk given at the Cracow Epiphany Conference on Astroparticle Physics, I discuss some of the opportunities provided by high-energy and ultra-high energy neutrino astronomy in probing particle physics beyond the standard model. Following a short summary of current and next generation experiments, I review the prospects for observations of high-energy neutrino interactions, searches for particle dark matter, and measurements of absolute neutrino masses, lifetimes and pseudo-Dirac mass splittings.
We discuss the prospects for high-energy neutrino astronomy to study particle physics in the energy regime comparable to and beyond that obtainable at the current and planned colliders. We describe the various signatures of high-energy cosmic neutrinos expected in both neutrino telescopes and air shower experiments and discuss these measurements within the context of theoretical models with a quantum gravity or string scale near a TeV, supersymmetry and scenarios with interactions induced by electroweak instantons. We attempt to access the particle physics reach of these experiments.
We point out the opportunity of tau neutrino astronomy for neutrino energies of the order of 10 GeV to 10$^{3}$ GeV. In this energy range, it is demonstrated that the flavor dependence in the background atmospheric neutrino flux leads to drastically different prospects between the observation of astrophysical muon neutrinos and that of astrophysical tau neutrinos. Taking the galactic-plane neutrino flux as a targeted astrophysical source, we found that the galactic-plane tau neutrino flux dominates over the atmospheric tau neutrino flux for neutrino energies beyond 10 GeV. Hence the galactic-p…
In an extention of the Standard Model by three relatively light right-handed neutrinos (the nuMSM model) the role of the dark matter particle is played by the lightest sterile neutrino. We demonstrate that the observations of the extragalactic X-ray background allow to put a strong upper bound on the mass of the lightest active neutrino and predict the absolute values of the mass of the two heavier active neutrinos in the nuMSM, provided that the mass of the dark matter sterile neutrino is larger than 1.8 keV.
In recent years, ground-based TeV gamma-ray observatories have made spectacular discoveries including imaging spectroscopy observations of galactic sources of different classes, and the discovery of rapid gamma-ray flares from radio galaxies and active galactic nuclei containing supermassive black holes. These discoveries, and the fact that gamma-ray astronomy has the potential to map the radiation from dark matter annihilation in our Galaxy and in extragalactic systems, have attracted the attention of the wider scientific community. The Division of Astrophysics of the American Physical Societ…
Although high energy neutrino astronomy is a multidisciplinary science, gamma ray bursts have become the theoretical focus since recent astronomical observations revealed their potential as cosmic particle accelerators. This spotlight is shared with investigations of the potential of high energy telescopes to observe oscillating atmospheric neutrinos. The Superkamiokande results have boosted atmospheric neutrinos from a calibration tool and a background for doing astronomy, to an opportunity to confirm the evidence for neutrino mass. Nevertheless, the highlights are mostly on the experimental …
Ultra High Cosmic Rays (UHECR) Astronomy may be correlated to a primary parental Neutrino Astronomy: indeed any far BL Lac Jet or GRB, sources of UHECR, located at cosmic edges, may send its signal, overcoming the severe GZK cut-off, by help of UHE ZeV energetic neutrino primary. These UHE neutrino scattering on relic light ones (spread on wide Hot Local Groups Halos) maybe fine-tuned : E_(nu) =(M_Z)^2/m_(nu) = 4 10^(22) eV *((0.1eV)/m_(nu)), to combine at once the observed light neutrino masses and the UHECR spectra, leading to a relativistic Z-Shower in Hot Dark Halos (e few tens Mpc wide) w…
Amplified Tau-airshower at horizons may well open a novel powerful windows, at PeV-EeV energy, to Neutrino Astronomy. Neutrino induced air-showering astronomy rise because of neutrino masses, their mixing and the consequent replenishment of tau flavor during neutrino flight into spaces; Tau-Air-Showers escaping the Earth are the main traces amplified by its millions muon, billions gamma and thousand billions photon secondaries. Earth edges and its sharp shadows is the huge beam-dump detector for UHE neutrino and the almost noise-free screen for tau air-showers (as well as for PeVs anti-neutrin…
How did neutrino astronomy evolve? Are there any useful lessons for astronomers and physicists embarking on new observational ventures today? We answer the first question; the reader can can decide if there are any useful parallels for other fields.
