Figure 8 - available via license: Creative Commons Attribution 4.0 International
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Dark matter fraction within the half-mass radius trends. Left panel: Dark matter fraction f DM versus stellar mass M * , with colours as in the right panel. Observations for LTGs from the SPARCS survey (Tortora et al. 2019) are included as a lilac solid line and shaded area, and observations for ETGs from the SPIDER survey (Tortora et al. 2014) are included as an aqua solid line and shaded area. Right panel: Dark matter fraction f DM versus in-situ fraction f in−situ for the Magneticum galaxies, with colours indicating the different accretion classes.
Source publication
In the two-phase scenario of galaxy formation, a galaxy's stellar mass growth is first dominated by in-situ star formation, and subsequently by accretion. We analyse the radial distribution of the accreted stellar mass in ~500 galaxies from the hydrodynamical cosmological simulation Magneticum. Generally, we find good agreement with other simulatio...
Contexts in source publication
Context 1
... we investigate if the fraction of dark matter within the half-mass radius, fDM, is correlated with the insitu fraction and stellar mass. As can be seen in Fig. 8, there is a broad tendency for galaxies with smaller in-situ fractions to have larger central dark matter fractions, indicating that (massive) accretion events lead to larger fractions of dark matter in the center by either enhancing the relative amount of dark matter in the center or dispersing the baryonic matter. This tendency can ...
Context 2
... observations show that LTGs have, at the same stellar mass, larger central dark matter fractions than ETGs ( Tortora et al. 2019, but also e.g., Courteau & Dutton (2015); Genzel et al. (2020), albeit they use velocity dispersions instead of stellar masses and different definitions of central radius). This can also be seen in the left panel of Fig. 8 where we included the observational results for LTGs and ETGs from Tortora et al. (2019) and Tortora et al. (2014), respectively. As can immediately be seen, most of the class D and F galaxies clearly resemble the properties of the LTGs, while the clear observed correlation between fDM and M * for ETGs is most strongly populated by ...
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