2010MNRAS.401.2521L


Query : 2010MNRAS.401.2521L

2010MNRAS.401.2521L - Mon. Not. R. Astron. Soc., 401, 2521-2530 (2010/February-1)

Testing newtonian gravity with AAOmega: mass-to-light profiles and metallicity calibrations from 47 Tuc and M55.

LANE R.R., KISS L.L., LEWIS G.F., IBATA R.A., SIEBERT A., BEDDING T.R. and SZEKELY P.

Abstract (from CDS):

Globular clusters (GCs) are an important test bed for Newtonian gravity in the weak-acceleration regime, which is vital to our understanding of the nature of the gravitational interaction. Recent claims have been made that the velocity dispersion profiles of GCs flatten out at large radii, despite an apparent paucity of dark matter (DM) in such objects, indicating the need for a modification of gravitational theories. We continue our investigation of this claim, with the largest spectral samples ever obtained of 47 Tucanae (47 Tuc) and M55. Furthermore, this large sample allows for an accurate metallicity calibration based on the equivalent widths of the calcium triplet lines and K-band magnitude of the Tip of the Red Giant Branch. Assuming an isothermal distribution, the rotations of each cluster are also measured with both clusters exhibiting clear rotation signatures. The global velocity dispersions of NGC 121 and Kron 3, two GCs in the Small Magellanic Cloud, are also calculated. By applying a simple dynamical model to the velocity dispersion profiles of 47 Tuc and M55, we calculate their mass-to-light profiles, total masses and central velocity dispersions. We find no statistically significant flattening of the velocity dispersion at large radii for M55, and a marked increase in the profile of 47 Tuc for radii greater than approximately half the tidal radius. We interpret this increase as an evaporation signature, indicating that 47 Tuc is undergoing, or has undergone, core-collapse, but find no requirement for DM or a modification of gravitational theories in either cluster.

Abstract Copyright: © 2009 The Authors. Journal compilation © 2009 RAS

Journal keyword(s): gravitation - stellar dynamics - globular clusters: individual

Simbad objects: 19

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Number of rows : 19
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 104 GlC 00 24 05.359 -72 04 53.20   5.78 4.09     ~ 3653 0
2 ESO 28-19 Cl* 00 24 47 -72 47.7   11.6 12.05     ~ 136 0
3 NGC 121 GlC 00 26 49.0 -71 32 10   11.2 11.24     ~ 286 0
4 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9859 1
5 ClG 0657-56 ClG 06 58 29.6 -55 56 39           ~ 839 1
6 NGC 2451A OpC 07 43 12 -38 24.0           ~ 89 0
7 NGC 2451B OpC 07 44 27 -37 40.0           ~ 69 0
8 M 68 GlC 12 39 27.98 -26 44 38.6   10.26 7.96     ~ 913 0
9 M 53 GlC 13 12 55.25 +18 10 05.4   8.95 7.79     ~ 750 0
10 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 3120 0
11 NAME Serpens Dwarf GlC 15 16 05.30 -00 06 41.0   15.1       ~ 654 1
12 GCl 38 GlC 16 10 59.00 +14 57 42.0           ~ 336 0
13 M 107 GlC 16 32 31.86 -13 03 13.6   9.96 8.85     ~ 732 0
14 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 1955 0
15 M 22 GlC 18 36 23.94 -23 54 17.1   7.16 6.17     ~ 1262 0
16 NAME SDG G 18 55 03.1 -30 28 42   4.5 3.6     ~ 1861 2
17 M 55 GlC 19 39 59.71 -30 57 53.1     6.49     ~ 787 0
18 M 15 GlC 21 29 58.33 +12 10 01.2   3       ~ 2969 0
19 M 30 GlC 21 40 22.12 -23 10 47.5     7.10     ~ 952 0

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2021.08.01-08:01:00

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