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

2. 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

4. * - 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

5. 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

6. Emissivity of Interstellar medium

7. Emissivity of Interstellar medium

8. Emissivity of Interstellar medium

9. 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)

10. T=20000 K

11. 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

12. Anisotropy

13. Anisotropy

14. 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