There will be several PhD positions open for application with a deadline of December 1, 2021. For details of the application procedure see this page. The positions are available in all the research areas in which the Observatory is active. This page will give a broad overview of possible research projects . However, research in different areas is possible and not all projects that might be offered are listed. The faculty research interests provides more background information.
When do the first massive galaxies in the universe build up their mass? Addressing this question has not been easy due to the lack of sensitive spectroscopy and mid-IR photometry for galaxies in the first billion years of the universe. Fortunately, thanks to the launch of the James Webb Space Telescope (JWST) and several ambitious on-going observing programs with the Atacama Large Millimeter Array (ALMA), we are on the brink of a revolution in our understanding of early build-up of massive galaxies. One of the most important of these observing programs is an on-going ALMA Cycle-7 Large Program Leiden University is leading to identify especially massive interstellar medium (ISM) reservoirs in the first 850 Myr of the Universe. Already >25 such ISM reservoirs have been identified from this program and its pilots, more than quadrupling numbers from prior programs. As exciting as these results are, the bulk of the science will come from a suite of follow-up observations from ALMA, JWST, the Jansky Very Large Array, Keck, and the Very Large Telescope. These data will allow for the first significant characterization of the mass build-up in massive galaxies in the early Universe, while probing obscured star formation rates, gas motions, merger rates, and physical conditions. We have an opening for a PhD student to take a leading role in the analysis of this exciting data set.
Constraining when and how the Universe made a phase transition from neutral to almost completely ionised remains a paramount goal of modern astrophysics. Powerful high-redshift radio galaxies and radio-loud quasars are important laboratories for studying this important phase. In the epoch of reionisation (z > 6), these radio-loud galaxies, the likely progenitors of brightest cluster galaxies, will significantly influence their environment on Mpc scales. They would also be unique beacons against which absorption by the neutral gas that pervaded the very early Universe can be seen in the HI 21cm line. The WEAVE-LOFAR survey will obtain about 1 million optical spectra and has been designed to identify the most suitable candidates to pursue for such deep HI absorption observations. In addition, Euclid will likely detect tens of radio-loud quasars at z > 7. Making use of LOFAR’s high angular and spectral resolution, the unfolding of the reionisation will be studied on the important kpc scales. These are inaccessible to ‘classical’ experiments that are limited to searching for HI fluctuations on tens of Mpc scales. This study will have profound consequences for our understanding of the epoch of reionisation.
The PhD students will be involved in the selection of extremely distant radio loud AGN, making use of the surveys with LOFAR, WEAVE and Euclid. Initially an important element will be working with the WEAVE data and later on followup of good candidates with LOFAR spectroscopy.