The gap between theory and observation in astronomy is larger than we thought, as there is no valid method to exam the theory which is derived from observation by explaining it. Thanks to numerical simulations, especially hydro-dynamical simulations, this link is not longer one-way (observation -> theory) any more. With the aid of mimicking observation techniques, we are able to build a two-way bridge, which allows us to test the theory by comparing the mock images with observed ones, and maybe to make suggestions to the observations.

With the aim of extending the usage of hydro-dynamical simulations – try to understand the differences between multi-wavelength observations and to make predictions/suggestions to observations! – this project uses a mass-and-volume completed galaxy cluster sample to test this idea. These galaxy clusters are selected from a series of cosmological simulations (see more detail in Cui et al. 2012 & 2014, and also in this page) with different version of baryonic models. There are about 180 clusters selected with M_{500} > 10^{14.5} [M_{sun}/h].

The optical images at various of bands, such as SDSS r, i, g, are produced by a SSP synthesis code, which is initially developed in Cui et al. 2011 & 2014. The mock X-ray images are generated by the PHOX code (Biffi et al. 2012 & 2013) with the Chandra ACIS-S responder applied. SZ signals for these clusters are simulated with the SZpack software (Chluba et al. 2012a and 2012b), which is integrated in the yt analysis models. Mock SZ images at multi-frequencies, e.g. 90 GHz, 180 GHz are simulated. The background image (can be downloaded at here) is showing the mimicked galaxy cluster at optical (a combination of SDSS u, g, r bands), X-ray and S-Z (90 GHz) bands. Upper cluster is a dynamical un-relaxed, while the lower cluster is dynamical relaxed.

In the first paper (Cui et al. 2016) of a series of three (planned) papers, we compared the galaxy cluster centres defined at multi-wavelength bands with the theoretical prediction, and probed the baryonic effect on that. Please see the “Mock observations” page or the paper for details.

In the second paper (Cui et al. 2017), we focused on only theoretical definitions of the cluster dynamical state as well as the baryonic effects on that. More informations can be found at the “Mock observations” page or the paper.

The third paper is under its way.