scholarly journals Neutrinos from colliding wind binaries: future prospects for PINGU and ORCA

2014 ◽  
Vol 1 ◽  
pp. 7-11 ◽  
Author(s):  
J. Becker Tjus

Abstract. Massive stars play an important role in explaining the cosmic ray spectrum below the knee, possibly even up to the ankle, i.e. up to energies of 1015 or 1018.5 eV, respectively. In particular, Supernova Remnants are discussed as one of the main candidates to explain the cosmic ray spectrum. Even before their violent deaths, during the stars' regular life times, cosmic rays can be accelerated in wind environments. High-energy gamma-ray measurements indicate hadronic acceleration binary systems, leading to both periodic gamma-ray emission from binaries like LSI + 60 303 and continuous emission from colliding wind environments like η-Carinae. The detection of neutrinos and photons from hadronic interactions are one of the most promising methods to identify particle acceleration sites. In this paper, future prospects to detect neutrinos from colliding wind environments in massive stars are investigated. In particular, the seven most promising candidates for emission from colliding wind binaries are investigated to provide an estimate of the signal strength. The expected signal of a single source is about a factor of 5–10 below the current IceCube sensitivity and it is therefore not accessible at the moment. What is discussed in addition is future the possibility to measure low-energy neutrino sources with detectors like PINGU and ORCA: the minimum of the atmospheric neutrino flux at around 25 GeV from neutrino oscillations provides an opportunity to reduce the background and increase the significance to searches for GeV–TeV neutrino sources. This paper presents the first idea, detailed studies including the detector's effective areas will be necessary in the future to test the feasibility of such an approach.

2015 ◽  
Vol 2 ◽  
pp. 57-62 ◽  
Author(s):  
M. Kroll ◽  
J. Becker Tjus ◽  
B. Eichmann ◽  
N. Nierstenhöfer

Abstract. It is generally believed that the cosmic ray spectrum below the knee is of Galactic origin, although the exact sources making up the entire cosmic ray energy budget are still unknown. Including effects of magnetic amplification, Supernova Remnants (SNR) could be capable of accelerating cosmic rays up to a few PeV and they represent the only source class with a sufficient non-thermal energy budget to explain the cosmic ray spectrum up to the knee. Now, gamma-ray measurements of SNRs for the first time allow to derive the cosmic ray spectrum at the source, giving us a first idea of the concrete, possible individual contributions to the total cosmic ray spectrum. In this contribution, we use these features as input parameters for propagating cosmic rays from its origin to Earth using GALPROP in order to investigate if these supernova remnants reproduce the cosmic ray spectrum and if supernova remnants in general can be responsible for the observed energy budget.


2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Hiromasa Suzuki ◽  
Aya Bamba ◽  
Ryo Yamazaki ◽  
Yutaka Ohira

Abstract In the current decade, GeV/TeV gamma-ray observations of several supernova remnants (SNRs) have implied that accelerated particles are escaping from their acceleration sites. However, when and how they escape from the SNR vicinities are yet to be understood. Recent studies have suggested that the particle escape might develop with thermal plasma ages of the SNRs. We present a systematic study on the time evolution of particle escape using thermal X-ray properties and gamma-ray spectra using 38 SNRs associated with GeV/TeV gamma-ray emissions. We conducted spectral fittings on the gamma-ray spectra using exponential cutoff power-law and broken power-law models to estimate the exponential cutoff or the break energies, both of which are indicators of particle escape. Plots of the gamma-ray cutoff/break energies over the plasma ages show similar tendencies to those predicted by analytical/numerical calculations of particle escape under conditions in which a shock is interacting with thin interstellar medium or clouds. The particle escape timescale is estimated as ∼100 kyr from the decreasing trends of the total energy of the confined protons with the plasma age. The large dispersions of the cutoff/break energies in the data may suggest an intrinsic variety of particle escape environments. This might be the cause of the complicated Galactic cosmic ray spectral shape measured on Earth.


2008 ◽  
Vol 17 (09) ◽  
pp. 1401-1409
Author(s):  
ANDREW M. TAYLOR

Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons also generate high energy neutrinos through their interactions with ambient matter and/or photons. However the predicted neutrino flux is reduced if cosmic ray sources accelerate not only protons but also a significant number of heavier nuclei, as is indicated by recent air shower data. I consider two plausible extragalactic class of sources, active galactic nuclei and gamma-ray bursts, and demand consistency with the observed cosmic ray composition and energy spectrum at Earth after allowing for propagation through intergalactic radiation fields. This allows me to calculate the degree of photo-disintegration and pion production expected to occur in these sources, and hence the neutrino fluxes from them.


2018 ◽  
Vol 27 (10) ◽  
pp. 1844023 ◽  
Author(s):  
Vladimir Zirakashvili

Cosmic ray acceleration by astrophysical shocks in supernova remnants is briefly reviewed. Results of numerical modeling taking into account the magnetic field amplification by streaming instability and the shock modification are presented. Nonthermal emission produced by accelerated particles in old supernova remnants is compared with available data of modern radio, X-ray and gamma-ray astronomies. It is also shown that high-energy neutrinos produced in young supernova remnants of Type IIn extragalactic supernova can explain the recent IceCube detection of astrophysical neutrinos.


1987 ◽  
Vol 125 ◽  
pp. 552-552
Author(s):  
A. K. Harding ◽  
J. J. Barnard ◽  
F. W. Stecker ◽  
T. K. Gaisser

Reports of air showers with E > 1015 eV from Cygnus X-3, LMC X-4, Vela X-1 and Hercules X-1 have been interpreted as requiring production of neutral secondaries by cosmic rays accelerated by the compact partner in these systems. If neutral pions are the source of photons that produce the observed air showers, then charged pions must also be produced, and they will give rise to neutrinos. We consider limits that may be placed on binary systems like Cygnus X-3 in which a neutron star is a strong source of ultra-high energy (UHE) particles that produce photons, neutrinos and other secondary particles in the companion star through nuclear interactions. The highest energy neutrinos (> 1 TeV), which have the largest interaction cross sections, are absorbed deep in the companion. From a detailed numerical calculation of the hadronic cascade induced in the atmosphere of the companion star, we estimate the neutrino production spectrum from an isotropic flux of monoenergetic 1017 eV protons and we estimate the resulting neutrino absorption in the stellar core. In the case of Cyg X-3 and LMC X-4, the cosmic-ray luminosities required to produce the observed gamma rays would result in energy deposition from neutrino absorption exceeding the intrinsic stellar luminosity of the companion. Over a timescale of 104−105 yr, the star would absorb its own binding energy and be disrupted. On shorter timescales, the energy deposition will cause significant expansion of the star, perhaps leading to quenching of high-energy signals from the source. From these results, we conclude that systems requiring intense UHE proton fluxes are either very young or the companion star is not the site of observed gamma-ray production. Alternatively, if the gamma-ray source is highly variable, the proton flux requirements would be lower, providing some relaxation of the above constraints.[See Gaisser et al. 1986, Ap. J. (Oct. 15), in press].


2019 ◽  
Vol 209 ◽  
pp. 01011
Author(s):  
Giulio Settanta ◽  
Stefano Maria Mari ◽  
Cristina Martellini ◽  
Paolo Montini

Cosmic Ray and neutrino oscillation physics can be studied by using atmospheric neutrinos. JUNO (Jiangmen Underground Neutrino Observatory) is a large liquid scintillator detector with low energy detection threshold and excellent energy resolution. The detector performances allow the atmospheric neutrino oscillation measurements. In this work, a discrimination algorithm for different reaction channels of neutrino-nucleon interactions in the JUNO liquid scintillator, in the GeV/sub-GeV energy region, is presented. The atmospheric neutrino flux is taken as reference, considering $\mathop {{v_\mu }}\limits^{( - )} $ and $\mathop {{v_e}}\limits^{( - )} $. The different temporal behaviour of the classes of events have been exploited to build a timeprofile-based discrimination algorithm. The results show a good selection power for $\mathop {{v_e}}\limits^{( - )} $ CC events, while the $\mathop {{v_\mu }}\limits^{( - )} $ CC component suffers of an important contamination from NC events at low energy, which is under study. Preliminary results are presented.


2018 ◽  
Vol 615 ◽  
pp. A168 ◽  
Author(s):  
Andrea Palladino ◽  
Walter Winter

Aims. We investigated the origin of observed astrophysical neutrinos. Methods. We propose a multi-component model for the observed diffuse neutrino flux. The model includes residual atmospheric backgrounds, a Galactic contribution (e.g., from cosmic ray interactions with gas), an extragalactic contribution from pp interactions (e.g., from starburst galaxies), and a hard extragalactic contribution from photo-hadronic interactions at the highest energies (e.g., from tidal disruption events or active galactic nuclei). Results. We demonstrate that this model can address the key problems of astrophysical neutrino data, such as the different observed spectral indices in the high-energy starting and through-going muon samples, a possible anisotropy due to Galactic events, the non-observation of point sources, and the constraint from the extragalactic diffuse gamma-ray background. Furthermore, the recently observed muon track with a reconstructed muon energy of 4.5 PeV might be interpreted as evidence for the extragalactic photo-hadronic contribution. We perform the analysis based on the observed events instead of the unfolded fluxes by computing the probability distributions for the event type and reconstructed neutrino energy. As a consequence, we give the probability of each of these astrophysical components on an event-to-event basis.


2015 ◽  
Vol 1 (4) ◽  
pp. 3-10 ◽  
Author(s):  
Алексей Кочанов ◽  
Aleksey Kochanov ◽  
Анна Морозова ◽  
Anna Morozova ◽  
Татьяна Синеговская ◽  
...  

The processing of the IceCube experiment data, obtained during 988 days (2010-2013), revealed 37 high-energy neutrino-induced events with deposited energies 30 TeV - 2 PeV. The hypothesis of an astrophysical origin of these neutrinos is confirmed at the statistical confidence level of 5.7 standard deviations. To identify reliably the neutrino events, a thorough calculation of the atmospheric neutrino background is required. In this work we calculate the atmospheric neutrino spectra in the energy range 100 GeV - 10 PeV with usage of several hadronic models and a few parametrizations of the cosmic ray spectra, supported by experimental data, which take into account the knee. It is shown that rare decays of short-lived neutral каоns K0_s contribute more than a third of the total electron neutrino flux at the energies above 100 ТeV. The account for kaons production in pion-nucleus collisions increases the electron neutrino flux by 5-7 % in the energy range 10^2 -10^4 GeV. Calculated neutrino spectra agree on the whole with the measurement data. The neutrino flavor ratio, extracted from the IceCube data, possibly indicates that the conventional atmospheric electron neutrino flux obtained in the IceCube experiment contains an admixture of the astrophysical neutrinos in the range 20 − 50 TeV.


2020 ◽  
Vol 634 ◽  
pp. A59 ◽  
Author(s):  
R. Brose ◽  
M. Pohl ◽  
I. Sushch ◽  
O. Petruk ◽  
T. Kuzyo

Context. Supernova remnants are known to accelerate cosmic rays on account of their nonthermal emission of radio waves, X-rays, and gamma rays. Although there are many models for the acceleration of cosmic rays in supernova remnants, the escape of cosmic rays from these sources has not yet been adequately studied. Aims. We aim to use our time-dependent acceleration code RATPaC to study the acceleration of cosmic rays and their escape in post-adiabatic supernova remnants and calculate the subsequent gamma-ray emission from inverse-Compton scattering and Pion decay. Methods. We performed spherically symmetric 1D simulations in which we simultaneously solved the transport equations for cosmic rays, magnetic turbulence, and the hydrodynamical flow of the thermal plasma in a volume large enough to keep all cosmic rays in the simulation. The transport equations for cosmic rays and magnetic turbulence were coupled via the cosmic-ray gradient and the spatial diffusion coefficient of the cosmic rays, while the cosmic-ray feedback onto the shock structure can be ignored. Our simulations span 100 000 years, thus covering the free-expansion, the Sedov–Taylor, and the beginning of the post-adiabatic phase of the remnant’s evolution. Results. At later stages of the evolution, cosmic rays over a wide range of energy can reside outside of the remnant, creating spectra that are softer than predicted by standard diffusive shock acceleration, and feature breaks in the 10 − 100 GeV-range. The total spectrum of cosmic rays released into the interstellar medium has a spectral index of s ≈ 2.4 above roughly 10 GeV which is close to that required by Galactic propagation models. We further find the gamma-ray luminosity to peak around an age of 4000 years for inverse-Compton-dominated high-energy emission. Remnants expanding in low-density media generally emit more inverse-Compton radiation, matching the fact that the brightest known supernova remnants – RCW86, Vela Jr., HESS J1731−347 and RX J1713.7−3946 – are all expanding in low density environments.


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