  The accretion of a cloud of hydrogen at the surface of a small, heavy star
produces a high energy mostly dissipated by electromagnetic radiation. The
combination of the absorption and the redshift of this radiation by hydrogen
explains all spectral observations: shapes of the broad lines, and their
anti-correlation with the radio-loudness, lack of lines in front of the Lyman
forest, value zb = 0.062 of the periodicity of the redshifts, correlation of a
high redshift with a thermal spectrum attributed to dust. These properties are
deduced from usual laws of physics without new parameters, they do not require
any non baryonic matter.
