Zusammenfassung
Since their discovery, submillimeter-selected galaxies (SMGs) have
revolutionized the field of galaxy formation and evolution. Hundreds of square
degrees have been mapped at submillimeter wavelengths and notwithstanding the
negative K-correction in the submm bands, where there is no significant loss of
sensitivity to the detection of these sources up to z~10, only a handful of
sources have been confirmed to lie at z>5 and only two at z>6. All of these
SMGs are rare examples of extreme starburst galaxies with star formation rates
(SFRs) of >1000 M_sun/yr and therefore are not representative of the general
population of dusty star-forming galaxies. Consequently, our understanding of
the nature of these sources, at the earliest epochs, is still incomplete. Here
we report the spectroscopic identification of a gravitationally amplified (mu =
9.3 +/- 1.0) dusty star-forming galaxy at z=6.027. After correcting for
gravitational lensing we derive an intrinsic SFR of 380 +/- 50 M_sun/yr for
this source, and find that its gas and dust properties are similar to those
measured for local Ultra Luminous Infrared Galaxies (ULIRGs), extending the
local trends up to an unexplored territory at high redshift. This ULIRG-like
galaxy at z=6 suggests a universal star-formation efficiency during the last
12.8 Gyr for dusty star-forming galaxies.
Nutzer