Summary

The K-band Multi Object Spectrograph (KMOS) is a second-generation instrument designed for operation on the VLT. The key feature of KMOS is its ability to perform Integral Field Spectroscopy in the near-infrared bands for 24 targets simultaneously.

The instrument design employs 24 configurable arms that position pickoff mirrors at user- specified locations in the Nasmyth focal plane. The sub-fields thus selected are then fed to 24 image slicer integral-field units (IFUs) that partition each sub-field into 14 identical slices, with 14 spatial pixels along each slice. Light from the IFUs is then dispersed by three cryogenic grating spectrometers which generate 14x14 spectra with ~1000 Nyquist-sampled spectral resolution elements for each of the 24 independent sub-fields. All 24 subfields have to be used with the same grating at a time.

The patrol field of the pickoffs is 7.2 arcmin in diameter, which is the diameter of the un- vignetted field at the VLT Nasmyth focus, thus minimizing the thermal background in the K- band. Each IFU has a square field of view of 2.8 x 2.8 arcsec; anamorphic magnification in the IFU fore-optics ensures uniform spatial sampling of 0.2 x 0.2 arcsec whilst maintaining Nyquist sampling (~2 pixel) of the spectral resolution element at the detector.

The use of focal-plane pick-off arms allows considerable flexibility in selecting targets and in particular the important capacity to deal with strongly clustered or close-paired sources. In addition to observing multiple individual sources, KMOS has the capability for integral field mapping of contiguous areas in an 8-point or 16-point dither pattern. The spectral resolution of R~3000-4000 provides velocity resolution for studies of low-mass objects and is optimal for OH-avoidance in the J & H bands. A lower resolution mode is also available in the combined H+K band.

Publications based on data obtained with the KMOS instruments should quote the following reference paper: Davies et al. 2013 (for the reduction software) and Sharples et al. 2013

A list of KMOS publications is provided in the following bibliography page.

Contact Information

• Questions related to proposal preparation, service mode, and visitor mode observations should be addressed via the contact form at  ESO Operations Helpdesk.
• Please, send us your general feedback, comments, suggestions, or report errors and inaccurate statements in the web pages and manuals also via this contact form.

Content of these pages

The following items are available on all the KMOS pages, using the bar on the left.

• Overview: a short description of the instrument
• News: list of changes affecting the instrument and/or its pages.
• Instrument Description: all the important parameters of the instrument.
• Manuals: links to all the documents related to KMOS.
• Tools: a collection of useful tools and informations for preparing and analyzing the KMOS observations.
• Instrument Operations Team
• Visitor Instructions: Instrument specific instructions for Visiting Astronomers