Damped Lyα Systems:
Metallicity Evolution and
Dust Obscuration
Michael Fall
STScI
2
Mean comoving density (for any quantity X):
Mean ISM metallicity (based on ZnII):
3
Input Star Formation History
Lilly et al. 1996, Madau et al. 1996, and many others
4
Output Interstellar Metallicity Evolution
SPF01
MC96
PFH99 -----
PF95 -----
Kulkarni & Fall 2002 5
New Observations
(Kulkarni, Fall, et al. 2005)
• HST/STIS measurements of ZnII and CrII absorption
lines in three DLA systems with 0.09 vs z relation for
0.1 may be an artifact of
a bias against selecting dusty (metal-rich) DLA
systems
11