Detecting neutrinos associated with the still enigmatic sources of cosmic rays has reached a new watershed with the completion of IceCube, the first detector with sensitivity to the anticipated ...fluxes. In this review, we will briefly revisit the rationale for constructing kilometer-scale neutrino detectors and summarize the status of the field.
We revisit the prospects for IceCube and similar kilometer-scale telescopes to detect neutrinos produced by the annihilation of weakly interacting massive dark matter particles (WIMPs) in the Sun. We ...emphasize that the astrophysics of the problem is understood; models can be observed or, alternatively, ruled out. In searching for a WIMP with spin-independent interactions with ordinary matter, IceCube is only competitive with direct detection experiments if the WIMP mass is sufficiently large. For spin-dependent interactions IceCube already has improved the best limits on spin-dependent WIMP cross sections by two orders of magnitude. This is largely due to the fact that models with significant spin-dependent couplings to protons are the least constrained and, at the same time, the most promising because of the efficient capture of WIMPs in the Sun. We identify models where dark matter particles are beyond the reach of any planned direct detection experiments while being within reach of neutrino telescopes. In summary, we find that, even when contemplating recent direct detection results, neutrino telescopes have the opportunity to play an important as well as complementary role in the search for particle dark matter.
Neutrino astronomy beyond the Sun was first imagined in the late 1950s. A neutrino detector at the bottom of Lake Baikal, the deployment of detectors in the Mediterranean Sea, and the construction of ...a kilometer-scale neutrino telescope at the South Pole exemplify current efforts to realize this dream.
Abstract
The origin of astrophysical high-energy neutrinos detected by the IceCube Neutrino Observatory remains a mystery to be solved. In this paper we search for neutrino source candidates within ...the 90% containment area of 70 track-type neutrino events recorded by the IceCube Neutrino Observatory. By employing the Fermi-LAT 4FGL-DR2, the Swift-XRT 2SXPS, and the CRATES catalogs, we identify possible gamma-ray, X-ray, and flat-spectrum radio candidate sources of track-type neutrinos. We find that based on the brightness of sources and their spatial correlation with the track-type IceCube neutrinos, the constructed neutrino samples represent special populations of sources taken from the full Fermi-LAT 4FGL-DR2/Swift-XRT 2SXPS/CRATES catalogs with similar significance (2.1
σ
, 1.2
σ
, 2
σ
at 4.8 GHz, 2.1
σ
at 8.4 GHz, respectively, assuming 50% astrophysical signalness). After collecting redshifts and deriving subsamples of the CRATES catalog complete in the redshift–luminosity plane, we find that the 4.8 GHz (8.4 GHz) subsample can explain between 4% and 53% (3% and 42%) of the neutrinos (90% C.L.), when the probability of detecting a neutrino is proportional to the (
k
-corrected) radio flux. The overfluctuations indicate that a part of the sample is likely to contribute and that more sophisticated schemes in the source catalog selection are necessary to identify the neutrino sources at the 5
σ
level. Our selection serves as a starting point to further select the correct sources.
With IceCube and its low-energy extension DeepCore, a neutrino detector with an energy reach from tens of gigaelectronvolt to exaelectronvolt has been commissioned. It measures the atmospheric ...neutrino spectrum from the lower energies where neutrinos oscillate to energies as large as 100 TeV with a statistic of more than 100,000 events per year. The initial results suggest that IceCube can measure the oscillation parameters in an energy range that exceeds existing observations by 1 order of magnitude, thus opening a new window on neutrino physics. We emphasize the search for sterile neutrinos particularly relevant to cosmology. We also discuss the first observation of (PEV) petaelectronvolt-Energy events that cannot be accommodated by the flux anticipated by extrapolation of the present atmospheric neutrino measurements.
Construction of the first kilometer-scale neutrino observatory has been completed; IceCube has been fully commissioned and has been taking data since May 2011. Its present performance exceeds ...expectations in both the neutrino collection area (by a factor 2 ∼ 3 depending on energy) and angular resolution. It continues to improve with ongoing refinements in calibration, software tools and our understanding of the optics of the natural ice. IceCube was designed more than a decade ago with the goal of observing the sources of both Galactic and extragalactic cosmic rays with good statistical significance after 5 years. Because the origin of cosmic rays is still unresolved, the exercise is inevitably performed on models. We here revisit three illustrative examples chosen because they are predictive, although with relatively large errors associated with the astrophysics of the sources: Galactic supernova remnants, gamma-ray bursts and GZK neutrinos produced in interactions of cosmic rays with the microwave background. We conclude that the IceCube design, as well as the prospect for observing neutrinos from cosmic-ray sources, have survived the test of time.
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