  The Impulsive Stimulated Raman Scattering (ISRS) is a parametric light-matter
interaction which shifts the frequencies of two ultrashort laser light pulses
by a non-quantified transfer of energy. As ISRS has no threshold, the laser
pulses may be replaced by the pulses which constitute the ordinary incoherent
light. This replacement has the expected qualitative effect on the time
constants required to observe ISRS: nanosecond collisional time and Raman
period. It has also a qualitative effect, the frequency shifts become
independent on the intensity; thus we use a new name for this avatar of ISRS:
"Incoherent Light Coherent Raman Scattering" (ILCRS).
  The coherence makes ILCRS very different from the ordinary Raman effect
proposed as an alternative to Doppler effect in the past: ILCRS is a stronger
light-matter interaction, it does not blur the images, nether the spectra; the
beams which receive energy are in the thermal radiation.
  The shifts of the spectra produced either by a Doppler effect, or by ILCRS
are very similar. However ILCRS is subject to a dispersion which perturbs
slightly the spectra. ILCRS is the key of a model of quasars which explains all
observations, without any new matter or physical theory: no fast moving cloud,
no dark matter, no variation of the fine structure constant, no invisible
object.
  The redshifts and the thermal radiation produced by ILCRS should not be
neglected a priori.
