New GIRAFFE Spectral Resolutions Characterised For All Settings

Published: 26 Aug 2015
FLAMES GIRAFFE Medusa stellar spectra

As announced in February 2015, the FLAMES GIRAFFE focusing procedure has been updated, resulting in significant improvement to the spectral resolution of the instrument. The spectral resolution characterisation has been completed for all grating settings and the new resolving powers are listed under the FLAMES News.

There is basically no change for the GIRAFFE low resolution (LR) modes, while the high resolution (HR) modes have significantly improved. In some settings the spectral resolution is much higher, and in almost all HR settings there is an increase of 20-30% with respect to the values before the February intervention. The new values are similar to those measured during the instrument commissioning.

The current version of the Giraffe Exposure Time Calculator (ETC) does not yet account for the improved focus, and will be updated soon. Preliminary measurements show no strong deviations in sensitivity from former values.