Searching for IMBHs in Galactic globular clusters through radial velocities of individual stars

TL;DR

This paper discusses a project to detect intermediate-mass black holes in Galactic globular clusters by analyzing radial velocities of individual stars across different regions, using advanced spectroscopic instruments.

Contribution

It introduces a novel methodology combining multiple spectroscopic instruments to build detailed velocity profiles for globular clusters, aiming to identify intermediate-mass black holes.

Findings

Development of velocity dispersion profiles for globular clusters

Constraints on the presence of intermediate-mass black holes

Application to the case of NGC 6388

Abstract

I present an overview of our ongoing project aimed at building a new generation of velocity dispersion profiles ad rotation curves for a representative sample of Galactic globular clusters, from the the radial velocity of hundreds individual stars distributed at different distances from the cluster center. The innermost portion of the profiles will be used to constrain the possibile presence of intermediate-mass black holes. The adopted methodology consists in combining spectroscopic observations acquired with three different instruments at the ESO-VLT: the adaptive-optics assisted, integral field unit (IFU) spectrograph SINFONI for the innermost and highly crowded cluster cores, the multi-IFU spectrograph KMOS for the intermediate regions, and the multi-fiber instrument FLAMES/GIRAFFE-MEDUSA for the outskirts. The case of NGC 6388, representing the pilot project that motivated the entire program, is described in some details.