Lyman-alpha Forest at z~2.0 in quasar spectrum

This chart shows a small part of the normalized UV-spectrum of the 16-mag QSO HE22-28 at z = 2.4, exposed for a total of 7.5 hours at spectral resolution about 40,000. It provides a fine illustration of the excellent quality of the reduced data from this instrument. Most of the lines are due to Lyman-alpha clouds at redshifts in the little-studied interval z = 1.9-2.1, cf. the text.