XClose

UCL Astrophysics Group

Home
Menu

PhD Projects: Cosmology and Surveys

Cosmic structures in the high-redshift Universe with DESI

DESI is already the largest spectroscopic redshift survey ever undertaken, with observations planned to continue into the 2030s. DESI accesses its highest redshifts through large samples of distant quasars and the sequence of absorption features in their spectra, known as the Lyman alpha forest, caused by the intervening large-scale structure of the Universe along the line of sight. The student will take a leading role in measuring the clustering in the Lyman alpha forest and its cross-correlation with the background quasars, as well as with other high-redshift tracers, e.g. from Euclid. Novel insights into the growth of cosmic structures will be inferred from this data. This project will be carried out as part of the DESI Collaboration and in collaboration with colleagues in Spain and the USA. Overseas students are particularly encouraged to apply. For this project we may be able to accept applications beyond the standard deadlines.

Contact: Prof Benjamin Joachimi (b.joachimi AT ucl.ac.uk


Cosmology from the Euclid space mission

The ESA Euclid mission launched in July 2023 and is now carrying out the most detailed deep-Universe galaxy survey from Space ever made. Exciting new constraints on cosmological structure formation, dark matter and dark energy will be derived from the clustering of galaxies and general relativistic gravitational lensing effects. The student will join the Euclid Consortium and the Euclid team in the UCL Astrophysics Group to make key contributions to the measurement of cosmological signals and the modelling of cosmological, astrophysical, and observational signatures. A particular focus of this PhD will be contributions to creating realistic and efficient simulations of the Euclid sky and implementing inference directly from simulation-based models.

Contact: Prof Benjamin Joachimi (b.joachimi AT ucl.ac.uk


Mapping and Measuring the Universe with DESI

The PhD project will focus on extracting cosmological and astrophysical information from the Dark Energy Spectroscopic Instrument (DESI, https://www.desi.lbl.gov/), which will map the 3D distribution of about 35 million galaxies. The survey has already reached a milestone, measuring over 20 million galaxy and QSO spectra. This is perfect timing for a PhD project starting in October 2024. UCL has contributed to the instrumentation and science of DESI since its early days, and the PhD student will become a member of the international DESI collaboration, working with teams from around the world. The work will use statistical measures such as Minimum Spanning Tree to characterise the Cosmic Web in the galaxy distribution observed by DESI, beyond the 2-point statistics, and further AI approaches.
See an outreach video: "5000 eyes: mapping the universe with DESI"

Contact: Prof Ofer Lahav (o.lahav AT ucl.ac.uk)


Related projects are also advertised under Cosmoparticle Physics and Extragalactic Astrophysics.