Turbulence properties in interstellar medium around Geminga TeV halo
Space power spectrum analysis is a common method to study the turbulence property of interstellar medium.In this paper,we applied this method to analyze a neutral hydrogen cloud near Geminga with data from the GALFA(galactic Arecibo L-band feed array)HI survey.The spatial power spectrum of the cloud can be well described by a power-law with an index of-4.0±0.1 which is steeper than the turbulent power spectrum of local galactic interstellar medium(the spectral index is larger than-3.0).We considered several physical conditions that may lead to the steeper spectrum and found none of the thin HI slice along the line of sight direction,highly ordered magnetic field perpendicular to line of sight direction or energy loss during the energy cascade be responsible for the steeper spectrum.This indicates that the turbulence property around Geminga is very different to the local galactic interstellar medium which may account for the abnormally low diffusion coefficient in Gemninga TeV halo.
interstellar mediumturbulenceGemingaspace power spectrum analysis
国家科技期刊平台
NSTL
万方数据
