The United Kingdom Astronomy Technology Centre

GMOS

The Gemini Multi-Object Spectrographs are twin instruments that have been supplied to both Gemini telescopes. GMOS is a collaborative project between the UK ATC, the Dominion Astrophysical Observatory, Canada and Durham University. It is a versatile instrument for optical spectroscopy, and has four main observing modes:

• direct imaging.
• long slit spectroscopy (generating spectra of thousands of contiguous points on a straight line 5.5 arcminutes long on the sky).
• multi slit spectroscopy using custom made masks (generating simultaneous spectra of many objects separated by up to 5.5 arcminutes on the sky).
• integral field spectroscopy (generating independent spectra simultaneously of a two-dimensional array of contiguous positions on the sky).

The fine image scale of GMOS will exploit the exceptional image quality from both the active and adaptive optics systems on the Gemini telescopes.

Examples of the many studies this instrument will support are:

• surveys of faint galaxies
• surveys of dark matter in low mass galactic systems
• integral field spectroscopy of intermediate-redshift objects to study kinematics, star formation and to obtain accurate distance estimates

GMOS N was delivered to Gemini North in Hawaii in April 2001 and saw first light in October 2001. GMOS S was delivered to Gemini South in Chile in November 2002 and was successfully commissioned in the following months.

More technical information about GMOS is available from the GMOS project pages, from the Gemini website.