Published online by Cambridge University Press: 17 September 2012
The emission properties of the components of the multiphase interstellar medium (ISM) require observations at very different wavelengths covering the range from X-rays for the hot phase to radio emission for the non-thermal component. This contribution gives an overview of the observational evidence for the presence of a multiphase ISM in halos of spiral galaxies. It is shown that the presence of halo gas correlates with the starformation rate in the disk. Recent radiocontinuum observations for NGC 253 are discussed with regard to the propagation of cosmic rays into the halos.