I am a staff astronomer at the observatory of Leiden University and work on the instrumentation projects ELT/METIS and VLTI/MATISSE.

My main research interest is in the nuclear regions of active galaxies (Active Galactic Nuclei, AGNs) which I study using very high spatial resolution techniques, such as infrared interferometry and adaptive optics, and with spectroscopy.

AGNs are thought to play a major role in transforming galaxies from gas-rich spiral galaxies to the so called ‘red and dead’ ellipticals, at least in the most luminous galaxies. There is some agreement that ‘AGN feedback’ is important in this transformation as it could push out the molecular gas out of which stars form. However, clear observational evidence for this outflow is very hard to collect, especially at high redshift where this ‘co-evolution’ mostly occurs. In ‘local’ AGNs, cosmic evolution does not play a role, but the physical processes in the nuclei can actually be resolved and studied in detail. It is my hope and my ambition that the insights we gain from resolved studies of the AGN phenomenon in the local universe will ultimately provide us with a better understanding of the global evolution of galaxies from the early universe until now.

Besides my instrumentation and astrophysical research, I am also a keen proponent of sustainable development and urgent climate action. Astronomers have a unique role to play in climate communication as we are the discipline that understands most keenly that there is really no planet B.


May 2021 – New paper out on the nuclear stellar populations of a sample of ultra-hard X-ray selected AGNs and control galaxies (the LLAMA sample). See my Twitter summary here (please see the tweet on Twitter to view the entire thread of 17 tweets):

Upcoming events

IR 2022: An Infrared Bright Future for Ground-based IR Observatories in the Era of JWST” is the follow-up conference to the ESO workshop IR 2020. The main goal of IR 2022 is to discuss ground-based thermal-infrared observations in the context of the now imminent launch of the James Webb Space Telescope (JWST).

IR 2022 will be a fully virtual, and free, event, designed to serve timezones from Alaska to Japan. The conference will be held 14-18 February 2022 and abstract submission is currently open until 26 November 2021.

I am currently moving my social media presence from Twitter to Mastodon

My Tweets