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1.
Non-thermal X-rays and very high energy (VHE) γ-rays have been detected from the supernova remnant (SNR) RX J1713.7−3946, and the recent observations with the Suzaku satellite clearly reveal a spectral cut-off in the X-ray spectrum, which directly relates to the cut-off of the energy spectrum of the parent electrons. However, whether the origin of the VHE γ-rays from the SNR is hadronic or leptonic is still in debate. We studied the multi-band non-thermal emission from RX J1713.7−3946 based on a semi-analytical approach towards the non-linear shock acceleration process by including the contribution of the accelerated electrons to the non-thermal radiation. The results show that the multi-band observations on RX J1713.7−3946 can be well explained in the model with appropriate parameters, and the TeV γ-rays have hadronic origin, i.e. they are produced via proton–proton interactions as the relativistic protons accelerated by the shock collide with the ambient matter.  相似文献   

2.
In this paper we show how to calculate the neutrino flux from a resolved source of high energy gamma-rays, of which have been measured fluxes and spectral indexes of each of the parts in which has been divided for the observations. For the calculation of the neutrino flux need to know the theoretical photon/neutrino ratios and have to consider the oscillation probability of neutrinos. As a numerical example the case of the Supernova Remnant RX J1713.7-3946 observed by H.E.S.S. experiment is presented here. Gamma-rays up to tens of TeV have been observed from RX J1713.7-3946, making this source a possible site of hadronic interactions and thus a source of neutrinos. The H.E.S.S. experiment observed 14 different regions in RX J1713.7-3946, measuring in each one the gamma-ray flux and spectral index. The technique presented in this paper can be applied to other high energy astrophysical sources, point-like or resolved.  相似文献   

3.
The Fermi γ-ray space telescope reported the observation of several Galactic supernova remnants recently, with the γ-ray spectra well described by hadronic pp collisions. The possible neutrino emissions from these Fermi detected supernova remnants are discussed in this work, assuming the hadronic origin of the γ-ray emission. The muon event rates induced by the neutrinos from these supernova remnants on typical km3 neutrino telescopes, such as the IceCube and the KM3NeT, are calculated. The results show that for most of these supernova remnants the neutrino signals are too weak to be detected by the on-going or up-coming neutrino experiment. Only for the TeV bright sources RX J1713.7-3946 and possibly W28 the neutrino signals can be comparable with the atmospheric background in the TeV region, if the protons can be accelerated to very high energies. The northern hemisphere based neutrino telescope might detect the neutrinos from these two sources.  相似文献   

4.
Cosmic rays are a sample of solar, galactic and extragalactic matter. Their origin and properties are one of the most intriguing question in modern astrophysics. The most energetic events and active objects in the Universe: supernovae explosion, pulsars, relativistic jets, active galactic nuclei, have been proposed as sources of cosmic rays although unambiguous evidences have still to be found. Electrons, while comprising ∼1% of the cosmic radiation, have unique features providing important information regarding the origin and propagation of cosmic rays in the Galaxy that is not accessible from the study of the cosmic-ray nuclear components due to their differing energy-loss processes. In this paper we will analyse, discussing the experimental uncertainties and challenges, the most recent measurements on cosmic-ray nuclei and, in particular, electrons with energies from tens of GeV into the TeV region.  相似文献   

5.
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6.
In 2004 and 2005, the shell-type supernova remnants RX J1713.7–3946 and RX J0852.0–4622 were observed and detected with the complete H.E.S.S. array, a system of four Imaging Cherenkov Telescopes located in Namibia and dedicated to the observations of γ-rays above 100 GeV. The energy spectra of these two sources have been measured over a wide energy range and revealed an integral flux above 1 TeV similar to that of the Crab Nebula. Their morphologies were resolved with high accuracy with H.E.S.S. and exhibit a striking correlation with the X-ray images, thereby pioneering a technique of unambiguously identifying spatially extended γ-ray sources. The results of the observations will be presented. Similarities and differences between these two sources will be pointed out as well as possible implications. M. Lemoine-Goumard, F. Aharonian, D. Berge, B. Degrange, D. Hauser, N. Komin, O. Reimer, U. Schwanke for the H.E.S.S. Collaboration  相似文献   

7.
在此介绍我们基于ＡＳＣＡ 和ＲＯＳＡＴ 等Ｘ 射线天文卫星,对３Ｃ３９７ 、Ｇ３２７ ．１１ ．１ 、Ｇ２１ ．５０ ．９ 和ＲＸＪ１７１３ ．７３９４６ 等超新星遗迹的物理特性进行的分析,简要地讨论了３Ｃ３９７ 的非平衡电离双热分量和双极泡结构以及Ｇ３２７ ．１１ ．１ 和Ｇ２１ ．５０ ．９ 中隐匿脉冲星的性质,并提出ＲＸＪ１７１３ ．７３９４６ 和ＡＤ３９３ 客星之间可能的关系。  相似文献   

8.
HEMAS-DPM is a Monte Carlo for the simulation of very high energy cosmic ray showers, which includes the DPMJET-II code based on the two component Dual Parton Model. DPMJET-II provides also charm production in agreement with data and, for p exceeding 5 GeV/c, with perturbative QCD results in proton-proton interactions. In this respect, a new scheme has been considered for the inclusive production of D mesons at large p in hadronic collisions in the framework of perturbative fragmentation functions, allowing an analysis at the Next to Leading Order (NLO) level which goes beyond the fixed I(s3) perturbative theory of open charm production. We have applied HEMAS-DPM to the calculation of the prompt muon component for Eμ ≥ 1 TeV in air showers considering the two extreme cases of primary protons and Fe nuclei.  相似文献   

9.
Gamma rays have been observed from two blazars at TeV energies. One of these, Markarian 421, has been observed also at GeV energies and has roughly equal luminosity per decade at GeV and TeV energies. Photon-photon pair production on the infrared background radiation is expected to prevent observation above 1 TeV. However, the infrared background is not well known and it may be possible to observe the nearest blazars up to energies somewhat below 100 TeV where absorption on the cosmic microwave background will give a sharp cut-off. Blazars are commonly believed to correspond to low power radio galaxies, seen down along a relativistic jet; as such they are all expected to have the nuclear activity encircled by a dusty molecular torus, which subtends an angle of 90 degrees or more in width as seen from the central source. Photon-photon pair production can also take place on the infrared radiation produced at the AGN by this molecular torus and surrounding outer disk. We calculate the optical depth for escaping γ-rays produced near the central black hole and at various points along the jet axis for the case of blazars where the radiation is observed in a direction closely aligned with the jet. We find that the TeV emission site must be well above the top of the torus. For example, if the torus has an inner radius of 0.1 pc and an outer radius of 0.2 pc, then the emission site in Mrk 421 would have be at least 0.25 pc above the upper surface of the torus, and if Mrk 421 is observed above 50 TeV in the future, the emission site would have to be at least 0.5 pc above the upper surface. This has important implications for models of γ-ray emission in active galactic nuclei.  相似文献   

10.
Loeb and Waxman have argued that high energy neutrinos from the decay of pions produced in interactions of cosmic rays with interstellar gas in starburst galaxies would be produced with a large enough flux to be observable. Their model is reexamined here and we obtain an upper limit to the diffuse neutrino flux from starburst galaxies. The upper limit obtained here is a factor of 5 lower than the flux which they predict. Our predicted neutrino flux would be below the atmospheric neutrino foreground flux at energies below 300 TeV and therefore would be unobservable. Compared with predicted fluxes from other extragalactic high energy neutrino sources, starburst neutrinos with PeV energies would have a flux considerably below that predicted for AGN models.

We also estimate an upper limit for the diffuse GeV γ-ray flux from starbust galaxies to be of the observed γ-ray background, much less than the component from unresolved blazars and more than an order of magnitude below the estimate of Thompson et al.  相似文献   


11.
Results of calculations of fluxes of prompt muons reaching the sea level are given for muon energies up to 107 GeV. The calculations are made in the frame of an empirical model and are based on the up-to-date data from experiments in cosmic rays, at accelerators, and on the most recent theoretical achievements on charm production in nucleon–air nucleus interactions.  相似文献   

12.
岳川 《天文学报》2020,61(5):59
宇宙线的观测研究和暗物质粒子的间接探测是高能天体物理领域两个重大研究课题. 自1912年V. Hess发现宇宙线开始, 人类对宇宙线的观测历史已经超过了一个世纪, 传统理论模型预言``膝''区以下能段的宇宙线能谱应服从单一幂率分布, 而近些年的空间和高空气球实验表明10 GeV--100 TeV的宇宙线质子能谱可能存在偏离单一幂律谱分布的重要结构, 这对研究银河系内宇宙线的起源、传播和加速机制具有重要意义. 另一方面, 得益于宇宙线和伽马射线观测精度的提高和观测能段的拓宽, 暗物质粒子的间接探测在国际上受到越来越多的关注, 暗物质粒子可能会发生湮灭或衰变产生稳定的普通高能粒子, 包括正负电子对、正反质子对、伽马射线和中微子等, 进而在宇宙线或伽马射线留下可探测的信号.  相似文献   

13.
The evolution of the cosmic ray primary composition in the energy range 106–107 GeV (i.e. the “knee” region) is studied by means of the e.m. and muon data of the Extensive Air Shower EAS-TOP array (Campo Imperatore, National Gran Sasso Laboratories). The measurement is performed through: (a) the correlated muon number (Nμ) and shower size (Ne) spectra, and (b) the evolution of the average muon numbers and their distributions as a function of the shower size. From analysis (a) the dominance of helium primaries at the knee, and therefore the possibility that the knee itself is due to a break in their energy spectrum (at EkHe=(3.5±0.3)×106 GeV) are deduced. Concerning analysis (b), the measurement accuracies allow the classification in terms of three mass groups: light (p,He), intermediate (CNO), and heavy (Fe). At primary energies E0≈106 GeV the results are consistent with the extrapolations of the data from direct experiments. In the knee region the obtained evolution of the energy spectra leads to: (i) an average steep spectrum of the light mass group (γp,He>3.1), (ii) a spectrum of the intermediate mass group harder than the one of the light component (γCNO2.75, possibly bending at EkCNO≈(6–7)×106 GeV), (iii) a constant slope for the spectrum of the heavy primaries (γFe2.3–2.7) consistent with the direct measurements. In the investigated energy range, the average primary mass increases from lnA=1.6–1.9 at E01.5×106 GeV to lnA=2.8–3.1 at E01.5×107 GeV. The result supports the standard acceleration and propagation models of galactic cosmic rays that predict rigidity dependent cut-offs for the primary spectra of the different nuclei. The uncertainties connected to the hadronic interaction model (QGSJET in CORSIKA) used for the interpretation are discussed.  相似文献   

14.
Muons from the “prompt” decays of charmed mesons in cosmic ray air showers start to show abundance on the atmospheric muon spectrum from few tens of TeV. Study of these prompt muons have broader interest in particle and astroparticle physics. The measurement of prompt muon in air showers is challenging because of their low production rate and the large amount of conventional muons produced in company with them. This paper describes the simulation study of a method that identifies prompt muon signatures based on the pattern of stochastic energy losses by muon bundles in deep under ice. The systematics associated with different hadronic interaction models and cosmic ray primary composition assumptions were estimated. Using IceCube as an example, we briefly discussed the challenge of using this method in experimental data analysis.  相似文献   

15.
Molecular clouds are expected to emit non-thermal radiation due to cosmic ray interactions in the dense magnetized gas. Such emission is amplified if a cloud is located close to an accelerator of cosmic rays and if energetic particles can leave the accelerator site and diffusively reach the cloud. We consider here a situation in which a molecular cloud is located in the proximity of a supernova remnant which is efficiently accelerating cosmic rays and gradually releasing them in the interstellar medium. We calculate the multiwavelength spectrum from radio to gamma rays which is emerging from the cloud as the result of cosmic ray interactions. The total energy output is dominated by the gamma-ray emission, which can exceed the emission in other bands by an order of magnitude or more. This suggests that some of the unidentified TeV sources detected so far, with no obvious or very weak counterparts in other wavelengths, might be in fact associated with clouds illuminated by cosmic rays coming from a nearby source. Moreover, under certain conditions, the gamma-ray spectrum exhibits a concave shape, being steep at low energies and hard at high energies. This fact might have important implications for the studies of the spectral compatibility of GeV and TeV gamma-ray sources.  相似文献   

16.
Quest for antimatter in cosmic rays has revealed no compelling evidence of primary, extragalactic antiparticles up to the present time. Recent positron and antiproton observations have been found to be consistent with a pure galactic origin up to energies of 50 GeV and 20 GeV respectively. In this paper it is discussed which role might be played by Ultra High Energy (UHE) extragalactic particles and antiparticles in cosmic-ray observations near Earth. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

17.
The AMANDA neutrino telescope has recently reported the detection of high-energy neutrinos spatially and temporally coincident with the flaring of the TeV blazar 1ES 1959 + 650. If high-energy neutrinos are in fact generated by this blazar, it would be the first strong evidence for the hadronic acceleration of cosmic rays. At present, the statistical significance of this observation cannot be reliably assessed, however. In this letter, we investigate whether circumstances exist where the source can produce the flux implied by the coincident events. We show that if the TeV gamma-ray emission observed from 1ES 1959 + 650 or other nearby TeV blazars is the result of accelerated protons interacting with nucleons, it is reasonable that AMANDA could detect several events during a flaring period. Such rates require that the spectral index of the source be rather high (for instance 2.8 for 1ES 1959 + 650) and that the Lorentz factor of the jet be fairly small (Γ  1).  相似文献   

18.
We investigate a possibility that non-thermal X-ray emission in a supernova remnant(SNR) is produced by jitter radiation, which is the analogue of synchrotron radiation in small-scale random magnetic fields. We can fit the multi-wavelength data of SNRs RX J1713.7-3946 (G347.3-0.5) and RX J0852.0-4622 (G266.6-1.2) by constructing pure jitter and inverse Compton (IC) emission models. We find that the physical fit parameters of random magnetic fields take values of several tens of μG strength and of the order of ∼107 cm correlation length. These properties of random magnetic fields in collisionless shock of SNRs are discussed.   相似文献   

19.
Long TeV γ-ray campaigns have been carried out to study the spectrum, variability and duty cycle of the BL Lac object Markarian 421. These campaigns have given some evidence of the presence of protons in the jet: (i) Its spectral energy distribution which shows two main peaks; one at low energies (∼1 keV) and the other at high energies (hundreds of GeV), has been described by using synchrotron proton blazar model. (ii) The study of the variability at GeV γ-rays and X-rays has indicated no significant correlation. (iii) TeV γ-ray detections without activity in X-rays, called “orphan flares” have been observed in this object.Recently, The Telescope Array Collaboration reported the arrival of 72 ultra-high-energy cosmic rays with some of them possibly related to the direction of Markarian 421. The IceCube Collaboration reported the detection of 37 extraterrestrial neutrinos in the TeV–PeV energy range collected during three consecutive years. In particular, no neutrino track events were associated with this source. In this paper, we consider the proton–photon interactions to correlate the TeV γ-ray fluxes reported by long campaigns with the neutrino and ultra-high-energy cosmic ray observations around this blazar. Considering the results reported by The IceCube and Telescope Array Collaborations, we found that only from ∼25% to 70% of TeV fluxes described with a power law function with exponential cutoff can come from the proton–photon interactions.  相似文献   

20.
An empirical formula for the cross section for inelastic hadronic interaction of antihelium with nuclei for the projectile energy range from 0.3 GeV/n to 80 GeV/n and target atomic mass number A from 4 to 120 has been developed. It is based on the available experimental data of nucleon (antinucleon) — nucleus and helium — nucleus inelastic cross sections. Such a formula is needed by experiments designed to search for antihelium in cosmic rays. With this formula one can estimate the efficiency of antihelium detection and correct for antihelium attenuation in the atmosphere for the balloon-borne experiments. A byproduct of this work is an empirical formula for antiproton-nucleus inelastic cross.  相似文献   

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