MUSE binaries in NGC 3201

DOI

We utilize multi-epoch MUSE spectroscopy to study binaries in the core of NGC 3201. Our sample consists of 3553 stars with 54883 spectra in total comprising 3200 main-sequence stars up to 4 magnitudes below the turn-off. Each star in our sample has between 3 and 63 (with a median of 14) reliable radial velocity (RV) measurements within five years of observations. We introduce a statistical method to determine the probability of a star showing RV variations based on the whole inhomogeneous RV sample. Using HST photometry and an advanced dynamical MOCCA simulation of this specific GC we overcome observational biases that previous spectroscopic studies had to deal with. This allows us to infer a binary frequency in the MUSE FoV and enables us to deduce the underlying true binary frequency of (6.75+/-0.72)% in NGC 3201. The comparison of the MUSE observations with the MOCCA simulation suggests a significant fraction of primordial binaries. We can also confirm a radial increase of the binary fraction towards the GC centre due to mass segregation. We discovered that in our sample at least (57.5+/-7.9)% of blue straggler stars (BSS) are in a binary system. For the first time in a study of GCs, we were able to fit Keplerian orbits to a significant sample of 95 binaries. We present the binary system properties of eleven BSS and show evidence that two BSS formation scenarios, the mass transfer in binary (or triple) star systems and the coalescence due to binary-binary interactions, are present in our data. We also describe the binary and spectroscopic properties of four sub-subgiant (or red straggler) stars. Furthermore, we discovered two new black hole (BH) candidates with minimum masses (Msini) of (7.68+/-0.50)M_{sun}, (4.4+/-2.8)M{sun}, and refine the minimum mass estimate on the already published BH to (4.53+/-0.21)M{sun}_. These BHs are consistent with an extensive BH subsystem hosted by NGC 3201.

Cone search capability for table J/A+A/632/A3/list (List of stars with radial velocity measurements)

Cone search capability for table J/A+A/632/A3/tablea1r (Radial velocities of RR Lyr and SXP stars (for 13 stars))

Cone search capability for table J/A+A/632/A3/tablea1m (Radial velocities of NGC 3201 members (for 3540 stars))

Cone search capability for table J/A+A/632/A3/tablea1n (Radial velocities of NGC 3201 nonmembers (for 40 stars))

Cone search capability for table J/A+A/632/A3/tablea2 (Orbital parameters of binaries)

Identifier
DOI http://doi.org/10.26093/cds/vizier.36320003
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/A+A/632/A3
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/632/A3
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/632/A3
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/A+A/632/A3
Provenance
Creator Giesers B.; Kamann; S.; Dreizler S.; Husser T.-O.; Askar A.; Goettgens F.,Brinchmann J.; Latour M.; Weilbacher P.M.; Wendt M.; Roth M.M.
Publisher CDS
Publication Year 2019
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy