Mark Gieles

Universitat de Barcelona

Experimental Sciences & Mathematics

Mark Gieles obtained his PhD in 2006 from Utrecht University in the Netherlands under the supervision of Prof Henny Lamers and Prof Simon Portegies Zwart. He then moved to the European Southern Observatory (ESO) in Chile as a research fellow and support astronomer on the Very Large Telescope (VLT) at Cerro Paranal in the Atacama desert. As part of this fellowship he spent 3 months as a visiting scientist at the School of Mathematics of the University of Edinburgh to work with Prof Douglas Heggie. In 2009 he won a Royal Society University Research Fellowship (URF) which he took up at the Institute of Astronomy of the University of Cambridge and moved the URF to the University of Surrey in 2013, where he started a new astrophysics research group. In 2013 he won a Starting Grant of the European Research Council (ERC) to work on the formation and evolution of the Milky Way, using its globular clusters.

Research interests

In my research I try to understand the formation and dynamical evolution of globular clusters to shed light on the stellar initial mass function (at high redshift), black hole dynamics, gravitational waves and the dark matter distribution in galaxies. Our Milky Way contains around 150 globular clusters, for which we have exquisite observations of the stars within them, including kinematics and chemistry. To understand these data, I use both star-by-star N-body simulations and theory. I recently developed a suite of dynamical models, that can be used to infer invisible mass, such as white dwarfs and black holes, from the motion of the visible stars. With this, I am searching for stellar-mass black holes and intermediate-mass black holes in clusters. The ESA-Gaia satellite is obtaining proper motions for a billion stars in our Galaxy and I am using these data to understand the intricate interplay between the gravity of globular cluster and the dark matter in the Milky Way. Another intriguing problem I am currently interested in, is the multiple population problem of globular clusters. In each cluster, the majority of stars have strange light element abundance. I recently proposed a new model for the formation of globular clusters, in which a supermassive star forms via stellar collisions and pollutes the cluster with the anomalous element abundances in the first few million years.

Selected research activities

Publications prior to the ICREA's appointment:

- Gieles M et al. 2018, 'Concurrent formation of supermassive stars and globular clusters: implications for early self-enrichment', MNRAS, vol 478, pp 2461--2479 

- Balbinot E & Gieles M 2018, 'The devil is in the tails: the role of globular cluster mass evolution on stream properties', Monthly Notices Of The Royal Astronomical Society, 474, 2, 2479 - 2492.    

- Schneider FRN et al. 2018, 'An excess of massive stars in the local 30 Doradus starburst', Science, 359, 6371, 69 - 71.

- Forbes DA et al. 2018, 'Extending the globular cluster system-halo mass relation to the lowest galaxy masses', Monthly Notices Of The Royal Astronomical Society, 481, 4, 5592 - 5605.  

- Forbes DA et al. 2018, 'Globular cluster formation and evolution in the context of cosmological galaxy assembly: open questions', Proceedings Of The Royal Society A-mathematical Physical And Engineering Sciences, 474, 2210, 20170616.

Gieles M et al. 2018, 'Mass models of NGC 6624 without an intermediate-mass black hole', Monthly Notices Of The Royal Astronomical Society, 473, 4, 4832 - 4839.

- Martinez-Medina LA et al. 2018, 'New insights into the origin and evolution of the old, metal-rich open cluster NGC 6791', Monthly Notices Of The Royal Astronomical Society, 474, 1, 32 - 44.

- Contenta F et al. 2018, 'Probing dark matter with star clusters: a dark matter core in the ultra-faint dwarf Eridanus II', Monthly Notices Of The Royal Astronomical Society, 476, 3, 3124 - 3136.