Team and acknowledgements

Below we acknowledge people who have contributed explicitly and implicitly to the development of X-PSI. If you wish to have your name removed, please notify the X-PSI Core team. Please also prompt us to update this page if you have engaged with this project: your time is a resource we wish to acknowledge. Specific patch or feature acknowledgements are often reported in the project History (CHANGELOG). Affiliations and contact details are only listed for team members to ease maintainability.

Core team

Those involved in maintenance and development (technical and scientific).

Current active members

  • Devarshi Choudhury (d.choudhury[at], University of Amsterdam

  • Bas Dorsman (b.dorsman[at], University of Amsterdam

  • Sebastien Guillot (sebastien.guillot[at], IRAP

  • Mariska Hoogkamer (m.m.hoogkamer[at], University of Amsterdam

  • Daniela Huppenkothen (d.huppenkothen[at], SRON

  • Yves Kini (y.kini[at], University of Amsterdam

  • Tuomo Salmi (t.h.j.salmi[at], University of Amsterdam

  • Serena Vinciguerra (s.vinciguerra[at], University of Amsterdam

  • Anna Watts (a.l.watts[at], University of Amsterdam

Past members

Thomas E. Riley ([at], the Initial Creator of X-PSI


Folks who have used X-PSI in their research or engaged with the team during development and science analysis, thereby prompting fixes or improvements.

  • Matteo Bacchetti

  • Anna Bilous

  • Erik Bootsma

  • Johannes Buchner

  • Yuri Cavecchi

  • Frank Chambers

  • Alex Chen

  • Julia Deneva

  • Siem Fenne

  • Gwénaël Loyer

  • Geert Raaijmakers

  • Paul Ray

  • Evert Rol

  • Rahul Silié

  • Emma van der Wateren

  • Bob de Witte

  • The NICER collaboration


Specific acknowledgements of people whose direct advice either influenced the direction of this project or led to some specific improvements.

  • CythonGSL header file

  • Existing open-source projects (which are either external dependencies or served as examples during the development of this project, such as emcee and stingray)

  • Daniela Huppenkothen (for pointing towards nested sampling algorithms and for abstract discussion of the statistical framework underlying X-PSI)

  • Will M. Farr & Ilya Mandel (for advice about posterior computation validation, and about model space definitions)

  • Will M. Farr (for ideas to accelerate likelihood function evaluation; WIP)

  • Sam Geen (for expanding support to include Windows OS)

  • Martin Heemskerk, Jeroen Roodhart, Satish Kamath and the SurfSARA servicedesk (for help with HPC issues).


This project is built upon the work of many researchers in many fields. For citations to (astro)physics and (astro)statistics literature, please see the technical documents pointed to in the Citation section. Moreover, we point to the bibliograpy of Riley et al. 2019 as the first published application of the X-PSI package, and to the ApJL Focus Issue of which this article is a member. For other scientific papers that have used X-PSI see Publications.


Development of X-PSI has been funded by two ERC Grants (PI Anna Watts), ERC Starting Grant No. 639217 CSINEUTRONSTAR and ERC Consolidator Grant No. 865768 AEONS.