Prediction of the diffuse neutrino flux from cosmic ray interactions near supernova remnants

In this paper, we present high-energy neutrino spectra from 21 Galactic supernova remnants (SNRs), derived from gamma-ray measurements in the GeV–TeV range. We find that only the strongest sources, i.e. G40.5-0.5 in the north and Vela Junior in the south could be detected as single point sources by IceCube or KM3NeT, respectively. For the first time, it is also possible to derive a diffuse signal by applying the observed correlation between gamma-ray emission and radio signal. Radio data from 234 supernova remnants listed in Green’s catalog are used to show that the total diffuse neutrino flux is approximately a factor of 2.5 higher compared to the sources that are resolved so far. We show that the signal at above 10 TeV energies can actually become comparable to the diffuse neutrino flux component from interactions in the interstellar medium. Recently, the IceCube collaboration announced the detection of a first diffuse signal of astrophysical high-energy neutrinos. Directional information cannot unambiguously reveal the nature of the sources at this point due to low statistics. A number of events come from close to the Galactic center and one of the main questions is whether at least a part of the signal can be of Galactic nature. In this paper, we show that the diffuse flux from well-resolved SNRs is at least a factor of 20 below the observed flux.     

The statistical effects of galactic tides on the Oort cloud

This report is a comment on two papers by Matese and Whitman (1989, 1992). We discuss here the applicability of uniform probability densities for the orbital parameters of the Oort cloud comets.     

“人·县·年”快速更新技术应用研究

为适应河南经济发展对基础测绘成果的需求,实现测绘服务模式的转变,河南省对1∶10 000基础地理信息数据更新,采取了“人·县·年”的快速更新模式,较好地满足了经济快速发展对基础测绘成果的需求,取得了良好的社会效益和经济效益.     

On the structure of thin magnetized accretion disks of active galactic nuclei and their coronal radiation

By taking magnetic stress in place of viscosity as the mechanism for angular moaentum transfer, the effect of frozen magnetic field on the structure of a geometrically thin accretion disk is examined. It is shown that the disk is quasi-Keplerian and its total luminosity is twice the luminosity in the standard disk model. In the inner region, there exists a narrow cool region and the highly collimated jet is formed under the action of the azimuthal component of the magnetic field. Also, we discuss the possibility that a magnetized corona be formed near the surface of the accretion disk and a wide band radiation issuing therefrom. The model suggested here can easily and reasonably explain the major AGN properties such as the radiation variation, the “bumps” in the optical, ultraviolet and soft X-ray ranges, etc.     

Generation of daylight reference years for two European cities with different climate: Athens, Greece and Bratislava, Slovakia

In this work, daylight reference years (DRYs), based on daylight and solar radiation measurements, are designed for two European cities, Athens, Greece and Bratislava, Slovakia, by using the Danish method, the Festa–Ratto technique and the Modified Sandia National Laboratories methodology. The data basis consists of 5-minute values of global and diffuse horizontal illuminance, global and diffuse horizontal irradiance, zenith luminance and solar altitude as well as of daily values of sunshine duration for 5 years for Athens and 8 years for Bratislava. Moreover, Linke's turbidity factor, luminous turbidity factor and relative sunshine duration are calculated and utilized. Then, for each DRY, the predominant sky-luminance distributions over Athens and Bratislava are identified, by using the methodology of Kittler et al., who corresponded the main sky conditions to 15 theoretical sky standards in diagrams of the ratio of zenith luminance to diffuse horizontal illuminance against solar altitude.For both cities the three aforementioned methods do not create identical DRYs. Despite the differences, the sky types defined for each of the two places seem not to depend on the choice of DRY. The predominant sky standard, for all of them, is a cloudless, polluted sky with a broad solar corona for Athens and an overcast sky with slight brightening towards the sun as well as very clear sky with low atmospheric turbidity for Bratislava. However, the selection of the DRY, which represents best the daylight conditions, is necessary for studies in saving energy in buildings. The DRY, which is created by the Modified Sandia National Laboratories method, is chosen for most cases, while the one created by the Danish method is also useful on certain occasions.     

Magnetic fields in the Galaxy

Abstract

Methods of measuring magnetic field strengths in astrophysics are reviewed. These determine that a magnetic field of 2–3μG lies approximately along the local spiral arm of the Galaxy. Faraday rotation measures indicate that abrupt field reversals occur in a number of directions. At the centre of the Galaxy, the field is vertical, i.e. perpendicular to the plane of the Galaxy.     

基于ESDA的中国年画网络店铺区位演化

通过收集淘宝网络店铺中的中国年画店铺基本信息,基于地级市空间统计单元,运用探索性空间数据分析理论中的全局自相关、局部自相关和热区分析等方法,对中国年画网络店铺区位的演化特征进行定量分析与挖掘。研究结果表明：1）中国年画网络店铺的区位演化整体上具有显著的空间自相关性,空间聚集特征明显;2）店铺区位局部差异明显,京、津、冀、鲁等省市构成了店铺区位选择的区域中心,并对周边城市产生辐射;3）店铺区位选择的热区从呈斑块状、阶梯状地域分布,逐渐演化为京、津、冀、鲁等稳定连片热区;4）总结了影响年画网络店铺区位选择的3个主要因素：区域经济因素、传统文化因素和消费者个性化需求因素。     

Galactic magnetic turbulence from radio data

Fluctuations in the Galactic synchrotron emission can be traced by the angular power spectrum of radio maps at low multipoles. At frequencies below few GHz, large-scale anisotropies are mainly induced by magnetic field turbulence, since non-thermal electrons radiating at these frequencies are uniformly distributed over the scales of magnetic field inhomogeneities. By performing an analysis of five radio maps, we extract constraints on turbulence spectral index and halo scale. Results favour a power spectrum significantly flatter than for 3D Kolmogorov-like turbulence, and a thin halo. This can be interpreted as an indication supporting non-conventional models of propagation of cosmic-ray particles in the Galaxy, or as a suggestion of a spectral-index break in the observed magnetic turbulence power spectrum.     

沿切向点轨迹CO和HⅠ的发射度与旋臂段的比较

为了在研究银河系结构时摆脱由运动学不确定性带来的困难,本文导出了沿银道面切向点轨迹HⅠ和CO发射度的径向和银经分布。所用的谱线资料范围是10°相似文献