Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218
Date Issued
2016
Author(s)
•
Ferraro, F. R.
•
Lovisi, L.
•
Contenta, F.
•
Vesperini, E.
•
•
Lapenna, E.
•
Lanzoni, B.
•
Mucciarelli, A.
•
•
Pallanca, C.
Abstract
We present an observational estimate of the fraction and distribution of dark mass in the innermost region of the two Galactic globular clusters NGC 6218 (M12) and NGC 288. Such an assessment has been made by comparing the dynamical and luminous mass profiles derived from an accurate analysis of the most extensive spectroscopic and photometric surveys performed on these stellar systems. We find that non-luminous matter constitutes more than 60 per cent of the total mass in the region probed by our data (R < 1.6 arcmin ∼ rh) in both clusters. We have carefully analysed the effects of binaries and tidal heating on our estimate and ruled out the possibility that our result is a spurious consequence of these effects. The dark component appears to be more concentrated than the most massive stars suggesting that it is likely composed of dark remnants segregated in the cluster core.
Volume
462
Issue
2
Start page
1937
Issn Identifier
0035-8711
Ads BibCode
2016MNRAS.462.1937S
Rights
open.access
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