First Detection of the [OIII] 88 micron Line at High Redshifts:
  Characterizing the Starburst and Narrow Line Regions in Extreme Luminosity
  Systems
  We have made the first detections of the 88 micron [OIII] line from galaxies
in the early Universe, detecting the line from the lensed AGN/starburst
composite systems APM 08279+5255 at z = 3.911 and SMM J02399-0136 at z =
2.8076. The line is exceptionally bright from both systems, with apparent
(lensed) luminosities ~10^11 L_solar. For APM 08279, the [OIII] line flux can
be modeled in a star formation paradigm, with the stellar radiation field
dominated by stars with effective temperatures, Teff >36,000 K, similar to the
starburst found in M82. The model implies ~35% of the total far-IR luminosity
of the system is generated by the starburst, with the remainder arising from
dust heated by the AGN. The 88 micron line can also be generated in the narrow
line region of the AGN if gas densities are around a few 1000 cm-3. For SMM
J02399 the [OIII] line likely arises from HII regions formed by hot (Teff
>40,000 K) young stars in a massive starburst that dominates the far-IR
luminosity of the system. The present work demonstrates the utility of the
[OIII] line for characterizing starbursts and AGN within galaxies in the early
Universe. These are the first detections of this astrophysically important line
from galaxies beyond a redshift of 0.05.
