A search for spectroscopic binaries in the galactic globular cluster M4. Based on 5973 individual spectra collected at VLT

Abstract

We present a large multi-epoch high resolution spectroscopic investigation for the search of binary candidates in the Galactic Globular Cluster (GGC) M4. The aim of our work is the identification of the binary candidates, and the determination of the binary fraction and of the binary radial distribution. We present a large multi-epoch high resolution spectroscopic investigation for the search of binary candidates in the Galactic Globular Cluster (GGC) M4. The aim of our work is the identification of the binary candidates, and the determination of the binary fraction and of the binary radial distribution. The average radial velocity of the observed cluster members is $70.29+/-0.07(+/-0.3)(+/-0.1)km/s. The search for variations in radial velocities among the stars with multi-epoch observations yielded 57 binary star candidates. Our radial velocity measurement accuracy allowed us to identify at a 3sigma level binaries with radial velocity variations larger than ~0.3km/s for the target stars with V<15, and larger than ~0.5km/s for the targets with V>15. We identified 4 binary star candidates out of 97 observed targets inside the core radius, and 53 candidates out of 2372 observed stars outside the core radius. Accounting for the incompleteness affecting our survey, the lower limit for the total binary fraction is f=3.0+/-0.3%. The lower limit for the binary fraction in the cluster core is f=5.1+/-2.3%, while outside the core it decreases to f=3.0+/-0.4%. Similarly, we found f=4.5+/-0.4% and f=1.8+/-0.6% for the binary fraction inside and outside the half mass radius.

13 pages, 12 figures, Accepted for publication in A&A

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Cited by in corpus (33)

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• A stellar census in globular clusters with MUSE: Binaries in NGC 3201
• MUSE crowded field 3D spectroscopy of over 12,000 stars in the globular cluster NGC 6397 - I. The first comprehensive spectroscopic HRD of a globular cluster
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• The End of the White Dwarf Cooling Sequence in M4: an efficient approach
• Lithium abundance in the globular cluster M4: from the Turn-Off to the RGB Bump
• MUSE crowded field 3D spectroscopy of over 12,000 stars in the globular cluster NGC 6397 - II. Probing the internal dynamics and the presence of a central black hole
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• The helium content of globular clusters: NGC6121 (M4)
• The halo+cluster system of the Galactic globular cluster NGC1851
• The incidence of binaries in Globular Cluster stellar populations
• Testing Newtonian gravity with distant globular clusters: NGC1851 and NGC1904
• Monte Carlo Simulations of Star Clusters - VI. The globular cluster NGC 6397
• The cluster ages experiment (CASE). V. Analysis of three eclipsing binaries in the globular cluster M4
• The binary fraction in the globular cluster M10 (NGC 6254): comparing core and outer regions
• Constraining the dark cusp in the Galactic Center by long-period binaries
• Fast rotating Blue Stragglers in the globular cluster M4
• The central dynamics of M3, M13, and M92: Stringent limits on the masses of intermediate-mass black holes
• Gravitational redshifts in main-sequence and giant stars
• Single-lined Spectroscopic Binary Star Candidates in the RAVE Survey
• High-velocity stars in the cores of globular clusters: The illustrative case of NGC 2808
• Atmospheric Parameters and Metallicities for 2191 stars in the Globular Cluster M4
• Single-lined Spectroscopic Binary Star Candidates from a Combination of the RAVE and Gaia DR2 surveys
• The X-ray Emissivity of Low-Density Stellar Populations
• The M4 Core Project with HST --- I. Overview and First-Epoch
• Binary properties of the globular cluster 47 Tuc (NGC 104). A dearth of short-period binaries
• The M4 Core Project with HST - IV. Internal Kinematics from Accurate Radial Velocities of 2771 Cluster Members
• VLT multi-epoch radial velocity survey toward NGC 6253. Analysis of three transiting planetary candidates
• Studying Binary Systems in Omega Centauri with MUSE. I. Detection of Spectroscopic Binaries
• Fewer Companions in the Crowd: The Low Close Binary Fraction in Globular Clusters from Gaia RVS
• Accurate orbital solution for the new and metal poor eclipsing binary Tycho~5227-1023-1