Kathy Romer

Clusters of galaxies as cosmological probes and astrophysical laboratories: making use of the latest X-ray and optical surveys

Supervisors: Dr Kathy Romer and Dr Paul Giles  (in collaboration with these international consortia XMM Cluster Survey, Dark Energy Survey, and LSST Dark Energy Science Collaboration (LSST:DESC) international consortia)

Abstract: Clusters of galaxies offer a unique window on the universe. As the largest collapsed objects in the heavens, they can be used to probe cosmology in a variety of ways. Moreover, they are host to a range of complex astrophysical processes and hold the key to unlocking mysteries such as the evolution of galaxies. The X-ray Cluster Science (XCS) project is an international, Sussex led, consortium (~20 scientists) that has uncovered more X-ray bright clusters than any other survey before it. This world leading project is ripe for scientific exploitation, with thousands of clusters available for individual or ensemble analysis. The ultimate goal of the XCS is to constrain models of Dark Energy, but a student would be able to choose from a variety of different science and analysis applications. The student would also be able to take part in the much larger (~500 scientists) Dark Energy Project - an optical project that has to detected 100 times more clusters than XCS using the signature of galaxy over density. The student would have the opportunity to work on XCS projects that have DES and DESC applications. They will also have the opportunity to get involved in several other upcoming international projects (Euclid, Athena, 4MOST etc.).

Skill development: the student will acquire generic research skills (literature searching, oral presentations, document preparation, setting/meeting goals etc.) through on the job training and through the specialist skills courses available through the University. The student will develop general astronomy skills (programming, use of astronomy archives, use of astronomy tools, proposal writing, optical observing, statistical analysis, data mining, data modelling etc.) through on the job training and workshops offered through the sepnet.ac.uk/sepnet-graduate-network and www.discnet.co.uk networks. The student will also develop, through mentorship from the supervisors and from self learning, several specialist astronomy skills that will be desirable to future postdoc employers in areas of observational cosmology and/or extragalactic astronomy. These specialist skills will depend somewhat on the choice of project, but might well include X-ray or optical spectroscopy, X-ray or optical image analysis, parallel programming, source detection, multi-wavelength studies, deep (machine) learning, and anomaly detection.

Opportunities for travel: Students will be encouraged to take part in DES and DESC consortia meeting in the UK and overseas. Students will take part in XCS meetings and in collaborative visits to XCS members overseas (e.g. USA, South Africa).  Participation in the Long Term Attachment (4+ months overseas) is encouraged. In addition to research related travel, Students will take part in several UK conferences; at least one International Summer School; and at least one international conference. (At the time of writing, there are not opportunities lined up to visit telescopes to carry out night time observations. However, the XCS team regularly submits proposals to gather more data, so this might well change.)

For a description of ongoing XCS projects, please refer to a recent ERC proposal that can be downloaded from this link: https://drive.google.com/file/d/1tEoLetxtQ1oUmVYq7_J_lJ6siP299-hE/view?usp=sharing

For an outreach level introduction to the subject area, please watch this video of a public talk given by Kathy in 2020: https://www.youtube.com/watch?v=wXPb5bfrHLk&t=15s