H-2 and HD absorption lines and the cosmic ray flux in high-z galaxies ; H2 ir HD molekulių absorbcijos linijos ir kosminių spindulių srautas galaktikose su dideliu raudonuoju poslinkiu

Cosmic ray flux in distant galaxies is so poorly known that even very rough and approximate methods may be useful in constraining this value of enormous importance for astrophysics, astrochemistry and astrobiology. Hereby we sketch a procedure for estimating the cosmic ray flux at remote locations where molecular hydrogen absorption lines have been detected. The procedure relies on assumptions whose validity in the local ISM has been independently verified, so it may be useful for much less accessible objects, especially damped Ly alpha absorption systems at high z. Since most of the low-energy cosmic rays in the Galactic environment are thought to originate in supernovae remnants, the link to the rate of high-mass star formation could, in principle, be established. We apply the method to a particular case of a high-redshift damped Ly alpha absorption system towards 0528-250 and obtain meaningful constraints.