HIFI 'first light' spectrum of DR21
HIFI obtained its first spectra on 22 June during the in-orbit commissioning phase of the Herschel mission. These observations, made before fine-tuning or in-orbit final calibration was performed, demonstrate that the instrument was performing better than expected. The first target for HIFI was DR21, a giant molecular cloud.
In this false-colour Spitzer image of the DR 21 star forming region, green reveals the emission from large molecules set aglow by the newly formed stars. The large bubbles and striated appearance of the cloud are caused by the complex dynamical interaction of the newly-formed massive stars and the environment from which they formed. On the right is an expanded view of the active region.
HIFI is designed to study this interaction of newly formed stars and their environment in detail. The blue and red boxes show the area that has been surveyed for ionized carbon, a key diagnostic of the molecular cloud material. The broad line at the position of the newly formed star (in red) reveals the presence of a powerful wind ripping the cloud apart. In contrast, the control position (in blue) shows emission from quiescent material, which has not yet been disturbed by this star. The yellow stripe indicates the region studied in lines of water (right) and carbon monoxide (left) by HIFI. The large width of the carbon monoxide profile and the complex and distorted water line again indicate that this material is part of a massive outflow from the newly formed star.