PhD grant

INPhINIT Incoming PhD Fellowship in Black hole mergers from star clusters

Deadline: 04.02.2021      CLOSED 
Quantity: 1
Contact email:


The doctoral fellowship programme INPhINIT "la Caixa" is devoted to attracting talented Early-Stage Researchers - of any nationality - who wish to pursue doctoral studies in Spanish or Portuguese territory. Sponsored by "la Caixa" Foundation, it is aimed at supporting the best scientific talent and fostering innovative and high-quality research in Spain and Portugal by recruiting outstanding international students and offering them an attractive and competitive environment for conducting research of excellence.

The Institute of Cosmos Sciences of the University of Barcelona is a research centre accredited with the Spanish Seal of Excellence María de Maeztu in 2020, the perfect place to carry out your PhD project through an INPhINIT Incoming fellowship.

Research project:

The detection of gravitational waves (GWs) has opened a new window in our understanding of the Universe. The vast majority of the GW detections by the Advanced LIGO-Virgo interferometers are binary black holes (BBHs) with stellar masses (< 100 solar masses). The origin of these BBHs is an open question: they may have a cosmological origin and be part of the dark matter in the universe. Alternatively, they have an astrophysical origin and formed from binary/triple massive stars, or in dynamical interactions in dense stellar systems such as star clusters (SCs).

Several studies have shown that dynamically formed BBH mergers in SCs might be the dominant contribution to BBH mergers in the Universe. The BBH merger rate and binary properties in this scenario depend sensitively on the initial properties of SCs that formed between now and more than 10 Gyr ago. This opens the possibility to constrain star and star cluster formation at high redshift byGWs. To achieve this, we need independent constraints on the formation of star clusters from star formation theory as well as the present-day properties ofSCs.

The staff at ICCUB works on comprehensive, multi-physics and multi-scale computational models of the long-term evolution of stars and BHs in star clusters (Prof MarkGieles) and star (cluster) formation (Prof Paolo Padoan). The student will also benefit from interactions with members of the ICCUB cosmology group led by ProfLicia Verde and the ICCUB Galactic dynamics group led by Prof Carme Jordi. The student will have access to large supercomputing allocations through the European PRACE program and local special-purpose hardware (Graphics ProcessingUnits, GPUs), to carry out state-of-the-art astrophysical simulations. The ICCUB is a full member of the Virgo collaboration and actively involved in Gaia and Weave, such that you will work on the forefront of computational astrophysics, GWs and Milky Way research.

Job position description:

The presence of BHs in SCs has consequences for the observed density profile, kinematics and escape rate of stars. The present-day properties of SCs and their stellar streams can therefore be used to constrain the demographics of BHs in SC today. In particular, the student will exploit the wealth of kinematics provided by the Gaia space telescope and related surveys such as Weave to study the properties of both dissolved and surviving SCs with the help of dynamical models for the evolution of SCs with BHs as well as mass models of the present-day mass distribution of SCs with BHs. These models are fast enough to be used in Bayesian inference techniques to derive constraints on the initial masses and densities of observed SCs in the Milky Way, as well as their evolution and resulting BBH mergers.

The student has the option to get involved in multi-physics and multi-scale simulations of star cluster formation, to obtain independent constraints on SC formation from star formation theory.

The results for the Milky Way SC population are extrapolated to compute the BBH merger rates of all SCs in the Universe across cosmic time. The predictions include merger rate as a function of redshift, BH mass, mass ratio and the distribution of orbital eccentricities. These will be compared to GW data of BBH mergers in the ongoing LIGOVirgo (and soon Kagra) observing runs, to provide tight constraints on the fraction of all BBH mergers that originate from the dynamical channel and use GWs to constrain star and SC formation both in the present and in the early Universe!

More information:

Website of Prof Mark Gieles

Website of Prof Paolo Padoan

Website of ICC

Paper discussing the contribution of BBH mergers from star clusters

Paper describing a fast model for the evolution of star clusters and resulting BBH merger

Paper on supermassive star formation in globular clusters

Employment conditions

The maximum total payment amount will be €122,592, as broken down below:

- Three annual payments of €34,800 each. Where applicable, the amounts corresponding to the Social Security contributions payable by the employer (in this case, the host institution), as well as any other compulsory fee, whether current or that may be provided for in a future legal framework, will be deducted from the yearly gross amount of €34,800 to be received by the fellow.

- €3,564 per year, as an additional amount for conferences, courses, research stays, consumables, equipment, charges for the use of intellectual property, etc.

The ”laCaixa” Foundation will award a prize of €7,500, which will be paid in the fourth year, should the fellow be able to deposit their thesis within 6 months after the third year of their fellowship has ended.

In addition to financial support, the fellowship includes a training programme on transversal skills, which has been specially designed by leading international institutions in the sector.

This programme includes aspects such as technology transfer, entrepreneurship, commercialisation of innovation, intellectual property, leadership, creativity, communication skills, teamwork, personal development, planning, assertiveness and networking.

Three sessions will be held: at the start of the fellowship, during the second year, and during the third year. Each session will last between 3 and 5 days, and attendance is mandatory for all fellows. The ”la Caixa” Foundation will coverall costs for these sessions, as well as the fellows’ accommodation and travel expenses.

For more information on the employment conditions, please refer to this document.

Working at the Institute of Cosmos Sciences

The Institute of Cosmos Sciences is a research institute of the University of Barcelona. It is an interdisciplinary centre dedicated to fundamental research in the fields of cosmology, astrophysics, and particle physics. In addition, the institute has a strong technology program through its participation in international collaborations in observational astronomy and experimental particle physics.

the institute of Cosmos Sciences has 50 professors, 10 ICREA professors, 37postdocs, 23 technicians and 61 PhD students. Postdoctoral staff at the ICCUBis largely international, above 60%.

Moreover, the ICCUB participates in many key international scientific consortia and projects, such as the Large Hadron Collider, the Gaia astrometric space mission, the MAGIC / CTA high-energy astrophysics telescopes, and the Virgo gravitational wave detector, among others. Additional information about the institute and the University of Barcelona can be found here.

The institute is situated in Barcelona, which offers an outstanding scientific and cultural environment, entertainment and sports as well as outstanding food and music.

You will be encouraged to contribute and interact with other researchers in the vibrant and international research environment as well as to participate in our outreach initiatives, more information at serviAstro and serviParticules.

The Institute of Cosmos Sciences is an equal employment opportunity employer. The Institute of Cosmos Sciences promotes a diverse and inclusive environment and welcomes applicants regardless of age, disability, gender, nationality, race, religion or sexual orientation. We strongly encourage women and underrepresented minorities in the physical sciences to apply. For additional information please see the Diversity, equity and inclusion Commission.


In order to be accepted, candidates must meet the following eligibility requirements:

  • Experience: At the call deadline, applicants must be in the first four years (full-time equivalent research experience) of their research careers and not yet have been awarded a doctoral degree.
  • Studies pursued: At the time of recruitment, candidates must comply with one of the following options:

- To have completed the studies that lead to an official university degree adapted to the European Higher Education Area awarding 300 ECTS credits, of which at least 60ECTS credits must correspond to master level.

- To have completed a degree in a university not adapted to the European Higher EducationArea that gives access to doctoral studies. The verification of an equivalent level of studies to the ones mentioned above will be made by the university when the admission procedure starts.

  • Geographic mobility: Candidates must not have resided or have carried out their main activity (work, studies, etc.) in Spain for more than 12 months in the 3 years immediately prior to the call deadline. Short stays, such as holidays, done in a country other than their country of usual residence (where they carried out their main activity), will be considered as time spent in their country of usual residence.
  • Level of English: Candidates must have a demonstrable level of English (B2 or higher).
  • Complete applications: Only candidates whose applications meet all the requirements of the call may be accepted.

For more information on the candidates' requirements, please refer to this document.

All applications must be submitted online through the following link. For more information on the application procedure, please refer to this document.

Inquiries about the application submission can be directed to

Deadline: Please submit your applications by February 4th 2021.

Selection process:

The process is comprised of three parts:

  • Eligibility screening: all applications received are screened and applications that do not fulfil the criteria published in the call for applications rules are rejected.
  • Remote evaluation (preselection): each of the eligible applications is sent to evaluation panel made up of two or three professors or researchers with broad experience in the discipline of the application and an extensive list of publications and/or contributions within this field. The application that receives the highest scores from each panel will pass to the next stage. The ”la Caixa” Foundation will notify candidates whether they have been shortlisted or not by e-mail on 22 April 2021.
  • Final evaluation (selection): candidates whose applications have passed the shortlisting stage will be called in for an interview before a multidisciplinary committee comprised of professors and researchers with extensive experience in selection processes by peer review. The interviews will be held in Barcelona on 25, 26 and 27 May 2021. The ”la Caixa” Foundation will notify interviewed candidates of the outcome of the process by e-mail on 7 June 2021.

The rating criteria that govern the selection process can be found in the Evaluation of applications section of the ”la Caixa” Fellowship Programme website.

For more information on the selection process, please refer to this document.