SIMBAD references

We discuss the generation of a regular magnetic field in an evolving spiral galaxy, starting at early stages immediately after the formation of the galactic gas disc. Our study is motivated by a recent claim of the detection of a strong (>1µG) regular magnetic field in very young galactic discs. It is shown that the hydromagnetic dynamo can produce a regular magnetic field of this strength at early stages of galactic evolution within a period of about 10⁹yr. The seed magnetic field compatible with this possibility can be the chaotic field generated by the turbulent motions in the (proto)galaxy. Among various effects of galactic evolution which are important for the mean-field dynamos, the decrease with time of the gas disc thickness is singled out as plausibly the most significant one.