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名稱Title
2021天文年會
國立嘉義大學蘭潭校區
5月21日至23日

論文摘要

Hunting for Ghost Galaxies in Cosmological Simulations.

[ Poster ]

ChungWen Wang

In the ΛCDM scenario, galaxies are formed in dark matter halos, but not all halos are able to form a galaxy. Efficient gas cooling through radiative processes is only possible for halos above a well-defined virial temperature threshold, which rises significantly at late times. If a halo hosting a galaxy merges with a more massive but star-free halo that has never exceeded the cooling threshold, the resulting system may look like a diffuse stellar halo without a 'central' galaxy. We call this the ‘ghost galaxy’ scenario. This may be one explanation for the ultra-diffuse galaxies recently discovered in low surface brightness surveys. In this research, we use the Copernicus Complexio (CoCo) simulation to search for ghost galaxies and study their properties. We find examples of galaxies merging into empty halos, although most of these cases have significant in situ star formation after the merger event. Only a few are still dominated by accreted stars at the present day. We will consider the impact of uncertainties in galaxy formation models and other approaches to predicting the abundance of ghost galaxies.