This week's PhD colloquia are highlighted.
|08/03||X-raying Extragalactic Gas: warm-hot gas in the EAGLE simulations|
I have studied the hot, diffuse gas around and between galaxies. Specifically, I have used the EAGLE numerical simulations of galaxy formation to predict the properties of this gas, and I have used those properties to predict specific observables: soft X-ray absorption and emission lines. Measuring this gas is challenging, but if we can observe and characterise it, we can learn much about the gas flows in and out of galaxies that regulate their formation and evolution. Observations of soft X-ray lines with future X-ray telescopes, such as Athena and XRISM, will enable us to do so. For these future X-ray telescopes, the strongest X-ray absorption lines and essentially all detectable line emission will come from the gaseous haloes surrounding galaxies. Some weaker, but still detectable absorption lines will come from the more diffuse gas outside these haloes. Photo-ionisation by the intergalactic ultraviolet/X-ray radiation background affects the absorption and emission lines of the very diffuse gas between galaxies, and the diffuse edges of the galaxy haloes. Emission from this photo-ionised gas is not expected to be detectable, but some absorption should be.
|Nastasha Wijers||Leiden Observatory|
|15:00||Exploring Strange New Worlds with High-Dispersion Spectroscopy|
Until 1995, the only planets known to orbit main-sequence stars were those of our own Solar System. Nearly three decades later, several thousand exoplanets have been discovered and substantial efforts have been made to explore these strange new worlds through spectroscopic analyses of their atmospheres. In particular, high-dispersion spectroscopy enables robust measurements of atmospheric chemical composition, structure, and dynamics. In this talk, I will present my contribution to investigating the significant, outstanding questions of exoplanetary science, such as What kinds of planets exist beyond our Solar System? Of what are they made? How did they form? and Is there life beyond Earth?
|Dilovan Serindag||Leiden Observatory|
For questions and/or suggestions concerning the colloquium series, please contact Ian Roberts (e-mail