TY - JOUR A1 - Göttgens, Fabian A1 - Husser, Tim-Oliver A1 - Kamann, Sebastian A1 - Dreizler, Stefan A1 - Giesers, Benjamin A1 - Kollatschny, Wolfram A1 - Weilbacher, Peter Michael A1 - Roth, Martin M. A1 - Wendt, Martin T1 - A stellar census in globular clusters with MUSE: A spectral catalogue of emission-line sources JF - Astronomy and astrophysics : an international weekly journal N2 - Aims. Globular clusters produce many exotic stars due to a much higher frequency of dynamical interactions in their dense stellar environments. Some of these objects were observed together with several hundred thousand other stars in our MUSE survey of 26 Galactic globular clusters. Assuming that at least a few exotic stars have exotic spectra (i.e. spectra that contain emission lines), we can use this large spectroscopic data set of over a million stellar spectra as a blind survey to detect stellar exotica in globular clusters. Methods. To detect emission lines in each spectrum, we modelled the expected shape of an emission line as a Gaussian curve. This template was used for matched filtering on the di fferences between each observed 1D spectrum and its fitted spectral model. The spectra with the most significant detections of H alpha emission are checked visually and cross-matched with published catalogues. Results. We find 156 stars with H alpha emission, including several known cataclysmic variables (CV) and two new CVs, pulsating variable stars, eclipsing binary stars, the optical counterpart of a known black hole, several probable sub-subgiants and red stragglers, and 21 background emission-line galaxies. We find possible optical counterparts to 39 X-ray sources, as we detected H alpha emission in several spectra of stars that are close to known positions of Chandra X-ray sources. This spectral catalogue can be used to supplement existing or future X-ray or radio observations with spectra of potential optical counterparts to classify the sources. KW - globular clusters: general KW - stars: emission-line, Be KW - novae KW - cataclysmic variables KW - catalogs KW - techniques: imaging spectroscopy Y1 - 2019 U6 - https://doi.org/10.1051/0004-6361/201936485 SN - 0004-6361 SN - 1432-0746 VL - 631 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Göttgens, Fabian A1 - Weilbacher, Peter Michael A1 - Roth, Martin M. A1 - Dreizler, Stefan A1 - Giesers, Benjamin A1 - Husser, Tim-Oliver A1 - Kamann, Sebastian A1 - Brinchmann, Jarle A1 - Kollatschny, Wolfram A1 - Monreal-Ibero, Ana A1 - Schmidt, Kasper Borello A1 - Wendt, Martin A1 - Wisotzki, Lutz A1 - Bacon, Roland T1 - Discovery of an old nova remnant in the Galactic globular cluster M 22 JF - Astronomy and astrophysics : an international weekly journal N2 - A nova is a cataclysmic event on the surface of a white dwarf in a binary system that increases the overall brightness by several orders of magnitude. Although binary systems with a white dwarf are expected to be overabundant in globular clusters compared with in the Galaxy, only two novae from Galactic globular clusters have been observed. We present the discovery of an emission nebula in the Galactic globular cluster M 22 (NGC 6656) in observations made with the integral-field spectrograph MUSE. We extracted the spectrum of the nebula and used the radial velocity determined from the emission lines to confirm that the nebula is part of NGC 6656. Emission-line ratios were used to determine the electron temperature and density. It is estimated to have a mass of 1-17 x 10(-5) M-circle dot. This mass and the emission-line ratios indicate that the nebula is a nova remnant. Its position coincides with the reported location of a "guest star", an ancient Chinese term for transients, observed in May 48 BCE. With this discovery, this nova may be one of the oldest confirmed extra-solar events recorded in human history. KW - globular clusters: individual: NGC 6656 KW - novae, cataclysmic variables KW - techniques: imaging spectroscopy Y1 - 2019 U6 - https://doi.org/10.1051/0004-6361/201935221 SN - 1432-0746 VL - 626 PB - EDP Sciences CY - Les Ulis ER -