Instructor: Gregory Fleishman Physics 777 Plasma Physics and Magnetohydrodynamics (MHD) Instructor: Gregory Fleishman Low-frequency radiation of the Galaxy F. Urtyev 9 December 2008

Study of the galactic low-frequency radiation (The Explorer 43) ULYSSES IMP-6 91 m dipole antenna Date of launch: 1971 WAVES 100 m dipole antenna Date of launch: 1994 ULYSSES 72 m dipole antenna Date of launch: 1994

* - Brown (IMP-6) Spectrum of the low-frequency galactic radiation Intensity Index of modulation [] – ISEE-3 (and ◊) O – Ulysses (Hoang) * - Brown (IMP-6) Tokarev et al, 2000 Dulk et al., 2001

Emissivity hot phase ISM component (ne=3*10-3 cm-3, T=104 K, B=3*10-6 G) warm phase ISM component (ne=3*10-2 cm-3, T=106 K , B=3*10-6 G) local cloud component near the Earth (ne=3*10-1 cm-3, T=7000K , B=3*10-6 G) α – filling factor τ – optical depth ε – emisivity k – coefficient of absorption

Emissivity of Interstellar medium

Emissivity of Interstellar medium

Emissivity of Interstellar medium

Absorption warm phase ISM component (ne=0.05 cm-3, T=5*103 K, Leff=0.5 kpc, filling factor α=50%) Reynolds clouds (zones of H II with low surface brightness) ne=0.2 cm-3, T=104 K, l=30-50 pc, filling factor α=20-50% local cloud component near the Earth (ne=3*10-1 cm-3, T=7000K , B=3*10-6 G)

T=20000 K

Low-frequency background radiation spectra Reynolds clouds ne=0.2 cm-3, T=2*104 K, l=40 pc, filling factor α=20 % hot ISM ne=3*10-3 cm-3, T=104 K, B=3*10-6 G warm ISM ne=3*10-2 cm-3, T=106 K local cloud ne=3*10-1 cm-3, T=7000K

Anisotropy

Anisotropy

Conclusion? Processes of radiation and propagation for low-frequency emission of the Galaxy significantly interact with surrounding medium Direct modeling of sources for this radiation will be able not only predict distribution of charged particles and spatial structure of magnetic fields in source but also will help to estimate parameters of different components of interstellar medium (density, temperature, filling factors) It could also help to check available models of ISM to ability for adequately description of observational data