Résumé / Abstract Journal-club_Galaxies

Journal-club Galaxies

« Searching for stellar-mass black holes in young star clusters »

Sara Saracino
Astrophysics Research Institute, Liverpool John Moores University (Liverpool, Royaume-Uni)

Black holes (BHs) are among the most mysterious and elusive objects in the Universe. The growing population of binary BHs unveiled so far by gravitational wave detectors clearly emphasizes how abundant they are in the Universe, and how important it is to analyze their properties in detail.

Unfortunately, only a few direct detections of BHs have been made so far in star clusters, due to the complication of this kind of studies, hence we know very little about the initial mass distribution of BHs as well as their dynamical evolution, all aspects which are closely linked to the evolution of the cluster itself.

In this context, a systematic search for stellar mass black holes in star clusters would allow to add important pieces of information in this complicated puzzle. Exploiting the technique developed by Giesers et al. 2018, 2019 which allowed to dynamically detect 3 BH candidates in the old globular cluster NGC 3201, we have recently started a large spectroscopic campaign with MUSE, to search for these objects in clusters of different ages. We have recently secured ~15 epochs of MUSE observations of NGC1850, a ~100 Myr old cluster in the Large Magellanic Cloud, spanning more than 2 years, an ideal temporal sampling for constraining the orbits of binary systems. First results show that a fair amount of stars in NGC 1850 are in binary systems, with some of them showing evidence of orbit around BHs. Such detections are very important for a cluster of this age, as this is the first step in constructing the initial mass function of BHs, a long standing open question in astrophysics.

jeudi 28 octobre 2021 - 11:30
Salle des séminaires Évry Schatzman, Institut d'Astrophysique
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