What are the typical features seen in quasar absorption lines of intergalactic clouds?
A)The hydrogen line is wider and lines from heavy elements are weaker at higher redshifts.
B)The hydrogen line is narrower and lines from heavy elements are weaker at higher redshifts.
C)The hydrogen line is wider and lines from heavy elements are stronger at higher redshifts.
D)The hydrogen line is narrower and lines from heavy elements are stronger at higher redshifts.
E)A few weak absorption lines are always seen at higher redshift than the quasar.

Question

Quizplus · Accepted Answer

The hydrogen line is wider and lines from heavy elements are weaker at higher redshifts. This is because the intergalactic medium is more ionized at higher redshifts, so there are fewer neutral hydrogen atoms to absorb photons and create absorption lines. The lines from heavy elements are also weaker at higher redshifts because the intergalactic medium is less dense at higher redshifts, so there are fewer heavy atoms to absorb photons and create absorption lines.

What Are the Typical Features Seen in Quasar Absorption Lines