We have surveyed Kepler's supernova remnant in search of the companion star of the explosion. We have gone as deep as 2.6 solar luminosities in the stars within 20% of the radius of the remnant. We use FLAMES at the VLT-UT2 telescope to obtain high resolution spectra of the stellar candidates selected from HST images. The resulting set of stellar parameters suggests that these stars come from a rather ordinary mixture of field stars (mostly giants). A few of the stars seem to have low [Fe/H] (< -1) and they are consistent with being metal-poor giants. The radial velocities and rotational velocities vrot sin i are very well determined. There are no fast rotating stars as vrot sin i < 20 km/s. The radial velocities from the spectra and the proper motions determined from HST images are compatible with those expected from the Besan\c{c}on model of the Galaxy. The strong limits placed on luminosity suggest that this supernova could have arisen either from the core-degenerate scenario or from the double-degenerate scenario.
@article{arxiv.1711.00876,
title = {No surviving companion in Kepler's supernova},
author = {Pilar Ruiz-Lapuente and Francesco Damiani and Luigi R. Bedin and Jonay I. Gonzalez Hernandez and Lluis Galbany and John Pritchard and Ramon Canal and Javier Mendez},
journal= {arXiv preprint arXiv:1711.00876},
year = {2018}
}