This data release provides 3D data cubes obtained from KMOS, the K-band Multi-Object Spectrograph. The instrument is located at the VLT UT1 telescope and has 24 image slicer Integral Field Units (IFUs) that can be placed independently in the patrol field of 7.2 arcmin diameter. Each IFU has 14 slices with 14 spatial pixels along each slice and a field-of-view of 2.8’’x2.8’’ which gives a spatial resolution of 0.2’’. Spectral resolving power depends on the grating and is between 2000 and 4200. This initial release consists of observations from October 2013 (i.e. start of operations) until February 2020. The content of the release grows with time as new data are being acquired and processed.

Data have been reduced using the KMOS pipeline version 2.7.3 or higher. Data reduction is executed first for each IFU containing an object. It includes sky subtraction, flat fielding, wavelength calibration, flux calibration, and cube reconstruction. Telluric absorption features in the individual cube spectra are corrected. For this, an atmospheric model is fit to the closest-in-time telluric standard star measurement using the molecfit software. This model is scaled with the airmass difference between science observation and standard star measurement and applied to the extracted spectra. Flux calibration is applied using the zero-point measurement from the same standard star, without assessment of the photometric conditions. Note that all standard stars serve both as telluric and as photometric standards.

The KMOS data collection is current to March 2020, when observations were halted because of the Coronavirus-induced lockdown. It will grow again with time as observations will resume, with future processing on a roughly monthly cadence. More details about the KMOS data and their structure are available in the associated Phase 3 data release description.

The KMOS data cubes tagged "KMOS" can be queried and downloaded using the Phase 3 generic query form which provides access to all Phase 3 data, or the Phase 3 spectral data query form with query parameters suited to harvest 3D cube data. KMOS data can be browsed and accessed via the ASP web interface or programmatically.