Studying the dynamical and thermal structure of the hot gaseous component in galaxy clusters by means of unprecedentedly detailed synthetic observations of advanced cosmological, hydrodynamical simulations
Final Report Abstract
Being the largest gravitationally–bound objects in the Universe, clusters can be treated as cosmological probes to constrain the underlying cosmological model. Additionally, they also represent optimal laboratories to study the baryonic physics and its interplay with structure formation. To keep the pace with observational improvements, we performed virtual observations of numerical hydro–simulations – which nowadays are able to simulate very large cosmic volumes with a variety of physical processes describing the baryonic component – to predict realistically the observable properties of galaxy clusters. This will enabled us to pursue forefront studies on large–scale structures and galaxy clusters. With special attention to the statistical treatment, we studied the strong gravitational lensing signal of galaxy clusters and investigated its predictional power to infer cosmological parameters from such observations. Using the full power of cosmological simulations we thereby investigated the effect of selection function of the underlying galaxy clusters sample, the change of the gravitational lensing signal by the complex, baryonic processes as well as the other uncertainties arising from evolution and sub-selection of clusters by there observed dynamical state. For X–ray observations, we extended a novel X–ray photon simulator, PHOX, capable to efficiently generate synthetic observations from both huge and high–resolution simulation outputs for the treatment of AGNs. We employed this tool to produce mock observations and investigate the X–ray emission from simulated galaxy clusters in order to deeply study the velocity field and thermo–dynamical structure of the intracluster medium and made predictions on the detectability of these properties with the up–coming X–ray missions. We demonstrated the power of such additional observations by Athena+, for instance, to reduce the scatter of scaling relations as well as studied the imprint of the AGNs on detectability of clusters by eROSITA. In addition we have deepened our understanding of the hydrostatic equilibrium of galaxy clusters and how deviations from it tempers our reconstruction of the total cluster mass, which is a key measurement for cosmological studies. Finally, all simulation data where made public via the cosmological web portal for hydrodynamical simulations (https://c2papcosmosim.uc.lrz.de/), where users can in addition perform virtual X–ray observations of galaxy clusters mimicking almost all current and planned X–ray instruments.
Publications
- ”Gravitational lensing in WDM cosmologies: the cross-section for giant arcs”, 2014, MNRAS, 441, 3, 1954-1963
Mahdi, H.S., van Beek, M., Elahi, P., Lewis, G.F., Power, C. Killedar, M.
(See online at https://doi.org/10.1093/mnras/stu705) - ”How do you weight a cluster of Galaxies?”, 2014, in the Astrostatiscs Journal of the Royal Statistical Society,, Issue 1/2014: ”Life, the universe, and everything”
Killedar, M.
(See online at https://doi.org/10.1111/j.1740-9713.2014.00785.x) - ”Cluster strong lensing: a new strategy for testing cosmology with simulations”, Statistical Challenges in 21st Century Cosmology, Proceedings of the International Astronomical Union, IAU Symposium, Volume 306, pp. 113-115
Killedar, M., Borgani, S., Fabjan, D., Dolag, K., Granato, G., Meneghetti, M., Planelles, S., Ragone-Figueroa, C.
(See online at https://doi.org/10.1017/S1743921314010916) - ”The overlooked potential of generalized linear models in astronomy - III. Bayesian negative binomial regression and globular cluster populations”, 2015, MNRAS, 453, 2, 1928-1940
de Souza, R.S., Hilbe, J. M., Buelens, B., Riggs, J. D., Cameron, E., Ishida, E. E. O., Chies- Santos, A. L., Killedar, M.
(See online at https://doi.org/10.1093/mnras/stv1825) - ”The overlooked potential of Generalized Linear Models in astronomy, I: Binomial regression”, 2015, Astronomy and Computing, Volume 12, 21-32
de Souza, R.S., Cameron, E., Killedar, M., Hilbe, J., Vilalta, R., Maio, U., Biffi, V., Ciardi, B., Riggs, J.D.
(See online at https://doi.org/10.1016/j.ascom.2015.04.002) - ”Simulation-based marginal likelihood for cluster strong lensing cosmology”, 2018, MNRAS, 473, 2, 1736-1750
Killedar, M., Borgani, S., Fabjan, D., Dolag, K., Granato, G., Meneghetti, M., Planelles, S., Ragone-Figueroa, C.
(See online at https://doi.org/10.1093/mnras/stx2262)
