I'm trying to use the Virial theorem to determine the mass of the M5 cluster and I need the velocity dispersion to calculate this. Does anyone know where I can find a table with these velocity dispersion constants?


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The relevant data for the M5 cluster can be found in Lanzoni et al. (2018.

Note that M5 is a clearly rotating cluster and that any averaged velocity dispersion will be affected by that. Also that the velocity dispersion is strongly dependent on radial distance from the centre of the cluster.

A rough value would be a 1-D (line-of-sight) dispersion of 5 km/s at an (angular) radius of 100 arcsec.


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