ForDyS Research Group at INAF Padova

This is the web page of the 'Formation and Dynamics of Stars' (ForDyS) research team at the Astronomical Observatory of Padova. We study the formation and dynamics of stars (and stellar remnants) by means of (many flavours of) N-body simulations.
Most of us work in Padova, a lively town in Italy, where Galileo made his first discoveries. Contact us, if you are curious to know more about our research (michela.mapelli[at]!

Further information


Formation and Dynamics of Stars in Galactic Nuclei:
Galactic nuclei are a unique laboratory to probe extreme physical processes, which occur in vicinity of supermassive black holes (SMBHs).
The innermost parsecs of a galaxy should be a hostile environment for star formation, since the SMBH' tidal shear disrupts any molecular cloud that approaches the galactic centre too much. Despite this, we DO observe hundreds of young stars in the innermost parsec of the Milky Way, and several hints point toward recent episodes of star formation in other nearby galactic nuclei. Recently, JVLA observations suggested even the presence of protoplanetary discs in the central parsec of our Galaxy.

What drives star formation so close to the monster?
We investigate the formation of stars around SMBHs, by means of N-body hydrodynamical simulations. We simulate the disruption of molecular clouds and the formation of circumnuclear rings in galactic nuclei. Our last and topmost challenge is to probe the existence of starless planets bound to SMBHs.
Do you remember Gravity, the movie?

People: Michela Mapelli, Alessandro Trani, Mario Spera, Ugo Di Carlo, Matteo Mazzarini
Recent publications: Mapelli & Gualandris 2015; Mapelli & Ripamonti 2015; Mapelli, Gualandris & Hayfield 2013; Mapelli et al. 2012.

The nursery of stars: when dynamics meets gas physics and stellar evolution
[05.jpg] Simulating young star clusters is a challenge for computational astrophysics. Three main aspects must be accounted for: (i) the hydro-dynamics of the parent molecular cloud, (ii) the dynamics of the newly formed stars, and (iii) the evolution of stars and binary systems.
The hydrodynamical treatment of the gas is particularly demanding because it requires both very high resolution and a suitable cooling function. Given the high density that can be reached in the core of dense young star clusters, the stellar component requires direct-summation N-body integrators, coupled with up-to-date recipes for stellar evolution and stellar winds.

Our new group at the Observatory of Padova is involved in the most innovative simulations of molecular clouds and young star clusters. We make use of special purpose hardware, especially graphics processing units (GPUs), to meet the challenge of coupling collisional stellar dynamics and stellar evolution.

People: Michela Mapelli, Mario Spera, Elisa Bortolas, Alessandro Trani, Enrico Montanari
Recent publications: Mapelli & the GES collaboration 2015; Trani, Mapelli & Bressan 2014; Mapelli & Bressan 2013.

Massive stellar black holes and intermediate-mass black holes: a keystone for the X-ray Universe and for gravitational waves
In 2009, Mapelli et al. proposed that black holes with mass >>20 Msun (up to 120 Msun) form from the direct collapse of massive stars with metallicity below solar. These massive stellar black holes (MSBHs) graze the mass range of intermediate mass black holes (IMBHs, 100-10 000 Msun) but are of merely stellar nature.
We investigate the impact of MSBHs and IMBHs on the evolution of the X-ray Universe (high-mass X-ray binaries, ultraluminous X-ray sources) from cosmic reionization to the local Universe.
Mergers of IMBHs and MSBHs with stellar black holes or other compact objects are expected to be a powerful source of gravitational waves in the frequency range of Advanced LIGO and Virgo. We are fond of multi-messenger astrophysics!

People: Michela Mapelli, Mario Spera, Brunetto Ziosi, Tom Kimpson
Recent publications: Spera, Mapelli & Bressan 2015; Ziosi, Mapelli et al. 2014; Mapelli & Zampieri 2014; Mapelli, Annibali et al. 2013; Mapelli, Zampieri et al. 2013; Mapelli et al. 2010; Mapelli et al. 2009.


[Elisa Bortolas]
Michela Mapelli (PhD) Mario Spera (PhD) Elisa Bortolas (Ms)
Assistant professor, team leader Postdoctoral fellow PhD student
[Ben Czaja]
Alessandro Alberto Trani (Mr) Brunetto Marco Ziosi (PhD) Ben Czaja (Mr)
PhD student Former PhD student Master student
SISSA, INAF-OAPD University of Padova, INAF-OAPD University of Padova, Astromundus fellow
[Matteo Mazzarini]
[Ugo Di Carlo.jpg]
Matteo Mazzarini (Mr) Ugo N. Di Carlo (Mr) Enrico Montanari (Mr)
Former Master Student Master Student Master Student
University of Padova University of Padova University of Padova
Tom Kimpson (Mr)
ERASMUS Master Student
University of Durham


  • March 15 2016: Ben Czaja joins our team as Master student. Welcome Ben!

  • March 10 2016: Matteo Mazzarini and Enrico Montanari successfully defended their theses. Congratulations!

  • March 3 2016: ForDyS on 'il Bo' (online magazine of the University of Padova) about the LIGO detection of two massive stellar black holes. Read our outreach paper (in Italian).

  • February 22 2016: ForDyS on MEDIA INAF about the LIGO detection of two massive stellar black holes. Read our outreach paper (in Italian).

  • February 11 2016: LIGO/Virgo's first direct detection of gravitational waves! The mass range of the two black holes (~36,29 Msun) is what we predicted since 2009! Recent paper by Mario Spera and the ForDys group referred to in the detection paper and in the astrophysics implication paper.
    A dream comes true: MASSIVE STELLAR BLACK HOLES EXIST!!!

  • December 15 2015: Michela Mapelli joins the MAORY Science Team. If you do not know what MAORY is read this. ForDyS gives a tiny contribution to the E-ELT!

  • December 10 2015: New paper on the dynamics of circumnuclear rings (by Alessandro Trani et al.) on astroph.

  • November 19 2015: Scighera, the new server of ForDyS is up and running. Welcome Scighera!

  • November 16 2015: Brunetto Ziosi successfully defends his PhD Thesis. Congratulations Brunetto!

  • October 20 2015: New paper on the formation of the circumnuclear ring in the Galactic Centre (by Michela Mapelli & Alessandro Trani) is on astroph.

  • October 1 2015: Elisa Bortolas joins our team as a new PhD student. Welcome Elisa!

  • September 23 2015: A NEW postdoctoral fellowship is available in our group. See the details at this link

  • July 9 2015: Tom Kimpson joins our team for an ERASMUS project. Welcome Tom!

  • June 24 2015: Michela Mapelli is awarded the MERAC prize for theoretical astrophysics!


  • Several PhD projects are available in our group (follow this link). Do not hesitate to contact me if you are intersted!

  • A NEW postdoctoral fellowship is available in our group. See the details at this link