MUSE library of stellar spectra

Abstract: Empirical stellar spectral libraries have applications in both extragalactic and stellar studies, and they have an advantage over theoretical libraries because they naturally include all relevant chemical species and physical processes. During recent years we see a stream of new high quality sets of spectra, but increasing the spectral resolution and widening the wavelength coverage means resorting to multi-order echelle spectrographs. Assembling the spectra from many pieces results in lower fidelity of their shapes. We aim to offer the community a library of high signal-to-noise spectra with reliable continuum shapes. Furthermore, the using an integral field unit (IFU) alleviates the issue of slit losses. Our library was build with the MUSE (Multi-Unit Spectroscopic Explorer) IFU instrument. We obtained spectra over nearly the entire visual band (lambda~4800-9300 Ang). We assembled a library of 35 high-quality MUSE spectra for a subset of the stars from the X-shooter Spectral Library. We verified the continuum shape of these spectra with synthetic broad band colors derived from the spectra. We also report some spectral indices from the Lick system, derived from the new observations. We offer a high-fidelity set of stellar spectra that covers the Hertzsprung-Russell diagram. It can be useful for both extragalactic and stellar work and demonstrates that the IFUs are excellent tools for building reliable spectral libraries.