Earlytype galaxy density profiles from IllustrisTNG: I. Galaxy correlations and the impact of baryons
Abstract
We explore the isothermal total matter radial density profiles in earlytype galaxies (ETGs) selected from the IllustrisTNG simulation. For a sample of 514 ETGs in the stellar mass range of $10^{10.7}\mathrm{M}_{\odot} \leqslant M_{\ast} \leqslant 10^{11.9}\mathrm{M}_{\odot}$ at $z = 0$, the total powerlaw slope has a mean of $\langle\gamma^{\prime}\rangle = 2.003 \pm 0.008$ and a standard deviation of $\sigma_{\gamma^{\prime}} = 0.175$ over the radial range from 0.4 to 4 times the stellar half mass radius. Several correlations between $\gamma^{\prime}$ and galactic properties including stellar mass, effective radius, stellar surface density, central velocity dispersion, central dark matter fraction and insituformed stellar mass ratio are compared to observations and other simulations, revealing that IllustrisTNG reproduce correlation trends qualitatively, and $\gamma^{\prime}$ is almost constant with redshift below $z = 2$. The powerlaw density profile of the ETG dark matter halos is steeper in the full physics (FP) run than their counterparts in the dark matter only (DMO) run. The dark matter inner slopes of the bestfit generalized NFW profile are much steeper than the standard NFW profile and they are anticorrelated (constant) with the halo mass in the FP (DMO) run. The dark matter inner slope is also anticorrelated with the halo concentration parameter $c_{200}$ in both runs. Comparison of the massweighted slope/central dark matter fraction correlation, $\gamma_{\mathrm{mw}}^{\prime}f_{\mathrm{DM}}$, with models and observations indicates contraction of the IllustrisTNG dark matter halos, especially in lowermass systems.
 Publication:

arXiv eprints
 Pub Date:
 November 2018
 arXiv:
 arXiv:1811.06545
 Bibcode:
 2018arXiv181106545W
 Keywords:

 Astrophysics  Astrophysics of Galaxies
 EPrint:
 23 pages, 18 figures, 8 tables. Submitted to MNRAS