Intergalactic Interactions: A Higgs Centre Workshop on the Intergalactic Medium

24.06.2013 to 28.06.2013
Avery Meiksin (Edinburgh), Sadegh Khochfar (Edinburgh), Martin White (Berkeley), James Bolton (Nottingham), Joseph Hennawi (MPIA), Joop Schaye (Leiden)

Royal Observatory, Edinburgh

Key Speakers:
G.Becker, N. Busca, S. Cantalupo, H.-W. Chen, C. Dalla Vecchia, A. Font-Ribera, M. Fumagalli, M. McQuinn, J. Miralda-Escude, J. O'Meara, B. Oppenheimer, P. Richter, S. Shen, D. Syphers, T. Theuns, T. Tripp, M. Viel and G. Worseck

The Cold Dark Matter (CDM) theory of cosmological structure formation has been a spectacular success. Its predictions for large-scale fluctuations in the Cosmic Microwave Background (CMB) have matched satellite measurements (most recently WMAP) to exquisite precision for a flat Universe. It has provided a broadly accurate description of the formation of structures from the largest scales to galactic, showing the structures form in a cosmic web resulting from gaussian fluctuations in the CDM primordial density field. When coupled with CMB constraints, best agreement is found for a Universe with a non-negligible contribution of vacuum energy to the total cosmological mass budget (a cosmological constant, or “Dark Energy”), in agreement with the acceleration of the universe discovered through supernova measurements.

It thus appears we have the correct broad framework for how cosmological structures were formed. The next simplest structure to the CMB is the large scale cosmic web, diffuse gaseous and dark matter fila- mentary structures between the galaxies, known as the Intergalactic Medium. The web contains most of the mass of the Universe. It is revealed through hydrogen and helium absorption lines in the spectra of distant Quasi-Stellar Sources (QSOs), which act as background lightbulbs against which the absorption is measured. The purpose of the workshop is to bring together world-leading experts in the study of the IGM as a test of the CDM model of structure formation on scales smaller than CMB measurements. It is here that additional physics may be discovered, such as required modifications to the nature of the CDM particles, or additional particles like massive neutrinos, or evolution in the vacuum energy equation of state.
The topics to be covered include the hydrogen and helium distributions in the IGM, cosmological constraints from the Lyman-alpha forest, the metal content of the IGM and the interaction between galaxies and their circumgalactic gas.
Directions to the Royal Observatory are available on the ROE Visitor Centre website: Directions
The banquet Wednesday, 26 June, starts at 19.30 (doors open 19.15). It is located in Rainy Hall, New College (on the Mound):  Directions

To Register, click on the (red) registration button below. Registration must include payment to the University of Edinburgh through ePay: Payment Page

Registration is £125 which includes lunches and the workshop dinner at Pollock Halls on the Wednesday evening. Limited partial support is available to students.

We now invite contributed talks and poster contributions - please submit abstracts via the registration form by **Tuesday 30th April**. Please note that space restrictions limit the number of additional attendees to 70.

LOC Members

Avery Meiksin (Chair), Pratika Dayal, Lyndsey Miller, Eric Tittley.


For general enquiries about the workshop please contact hc-igm13 [at]