Gemini Infrared Multi-Object Spectrograph: preliminary design overview

The Gemini Infrared Multi-Object Spectrograph (GIRMOS) is an adaptive optics-fed multi-object integral field spectrograph with a parallel imaging capability. GIRMOS implements multi-object adaptive optics (MOAO) for each of its spectrographs by taking advantage of the infrastructure offered by Gemini upcoming wide-field AO facility at Manua Kea. The instrument offers the ability to observe four objects simultaneously within the Gemini-North AO (GNAO) system’s field-of-regard or a single object by tiling the four fields that feed light to four separate spectrographs. Each integral field spectrograph has an independent set of selectable spatial scales (0.025", 0.05", and 0.1" /spaxel) and spectral resolution (R 3,000 and 8,000) within an operating band of 0.95 2.4µm. These spatial scales correspond to indvidual spectrograph fields of view of 1x1", 2X2" , and 4x4", respectively. GIRMOS’s imager offers Nyquist sampling of the diffraction limit in H-band over a 85x85" imaging field. The imager can function in a parallel data acquisition mode with just minor vignetting spectroscopic pick- offs when they are deployed.