(matter in a galaxy between star systems)
The interstellar medium (ISM) is
matter such as dust and gas between stars.
(Matter between entire galaxies is called the intergalactic medium.)
The gas may be ionized, neutral, or molecular.
Density varies from as little as 1 per
10,000 cm3 to 1,000,000 per cm3.
The interstellar medium was first deduced
through observed absorption lines.
Types of ISM regions that have been detected:
- molecular clouds, generally 10-20K temperature.
- cold neutral medium (CNM), 50-100K.
- warm neutral medium (WNM), 6000-10000K.
- warm ionized medium (WIM), 8000K.
- HII regions, 8000K.
- Coronal gas/Hot Ionized Medium (HIM), 1000-3000K.
dark matter halo
dense core mass function (DCMF)
diffractive interstellar scintillation (DISS)
extreme ultraviolet (EUV)
star formation feedback
galactic electron density
ionization correction factor (ICF)
intergalactic medium (IGM)
Interstellar Medium Absorption Profile Spectrograph (IMAPS)
interplanetary medium (IPM)
refractive interstellar scintillation (RISS)
submillimeter galaxy (SMG)