Max Planck Institute for Astronomy - Annual Report 2007

46 II. Highlights
F [10 –23 W cm –2 nm –1 ]
2.5
2
1.5
1
0.5
0
2.5
2
1.5
1
0.5
0
2.5
2
1.5
1
0.5
0
2.5
2
1.5
1
0.5
0
2.5
2
1.5
1
0.5
0
280 300 320
1.9
1.9
1.9
1.9
1.9
The element abundance ratio could be determined
from the intensity ratio of the Fe II to Mg II lines in the
spectra of five selected quasars (Fig. II.6.3). The values
found are between two and five with an accuracy of 20
to 40 percent.
A comparison with other research results is not
trivial, because these were partially obtained through
other methods and the uncertainties are rather large.
Furthermore, how exactly the Fe II to Mg II line ratio
reflects the actual abundance ratio has not been completely
understood. Still, the comparison shown in Fig.
Rest frame wavelength [nm]
340 360
J0836+0054
2 2.1 2.2 2.3 2.4 2.5
280 300 320 340 360
J0005–0006
2 2.1 2.2 2.3 2.4 2.5
280 300 320 340 360
J1411+1217
2 2.1 2.2 2.3 2.4 2.5
280 300 320 340
J1306+0356
2 2.1 2.2 2.3 2.4 2.5
260 280 300 320 340
Fig. II.6.3: Spectra of five quasars in the range of the Mg-II line.
Several characteristics are highlighted in color: solid blue: fit
to the emission line; solid red: continuum; dotted red: Balmer
continuum; solid green: template spectrum for Fe II; dotted
blue: noise limit.
J1030+0524
2 2.1 2.2 2.3 2.4 2.5
Observed frame wavelength [m]
II.6.4 is informative: The new analysis more or less
confirms the general trend of previous results according
to which – even at large redshifts – no evolutionary
trend is indicated. Because the universe was around 900
million years old at z 6, the enrichment with heavy
metals must have already progressed much earlier. If
one assumes a typical en-richment period of 300 million
years, then the star formation era must have already been
triggered at redshiftings beyond z 8. This result sets
scales for future attempts at finding the stars of the earliest
generation (population III).
The Masses of the Central Black Holes
As described at the outset, the evolution of black holes is
closely linked to the evolution of galaxies. The evolution
of black hole masses could provide insight into this still