ABSTRACT We explore the isothermal total density profiles of early-type galaxies (ETGs) in the IllustrisTNG simulation. For the selected 559 ETGs at z = 0 with stellar masses $10^{10.7}\, \mathrm{M}_{\odot } \leqslant M_{\ast } \leqslant 10^{11.9}\, \mathrm{M}_{\odot }$, the total power-law slope has a mean of 〈γ′〉 = 2.011 ± 0.007 and a scatter of $\sigma _{\gamma ^{\prime }} = 0.171$ over the radial range 0.4–4 times the stellar half-mass radius. Several correlations between γ′ and galactic properties including stellar mass, effective radius, stellar surface density, central velocity dispersion, central dark matter fraction, and in situ-formed stellar mass ratio are compared to observations and other simulations, revealing that IllustrisTNG reproduces many correlation trends, and in particular, γ′ is almost constant with redshift below z = 2. Through analysing IllustrisTNG model variations, we show that black hole kinetic winds are crucial to lowering γ′ and matching observed galaxy correlations. The effects of stellar winds on γ′ are subdominant compared to active galactic nucleus (AGN) feedback, and differ due to the presence of AGN feedback from previous works. The density profiles of the ETG dark matter haloes are well described by steeper than NFW profiles, and they are steeper in the full physics (FP) run than their counterpartsmore »
Beyond mass: detecting secondary halo properties with galaxy-galaxy lensing
Secondary halo properties beyond mass, such as the mass accretion rate (MAR), concentration, and the half mass scale, are essential in understanding the formation of large-scale structure and dark matter haloes. In this paper, we study the impact of secondary halo properties on the galaxy-galaxy lensing observable, ΔΣ. We build an emulator trained on N-body simulations to model ΔΣ and quantify the impact of different secondary parameters on the ΔΣ profile. We focus on the impact of MAR on ΔΣ. We show that a 3σ detection of variations in MAR at fixed halo mass could be achieved with the Hyper Suprime Cam survey assuming no baryonic effects and a proxy for MAR with scatter <1.5. We show that the full radial profile of ΔΣ depends on secondary properties at fixed halo mass. Consequently, an emulator that can perform full shape fitting yields better than two times improvement upon the constraints on MAR than only using the outer part of the halo. Finally, we highlight that miscentring and MAR impact the radial profile of ΔΣ in a similar fashion, implying that miscentring and MAR need to be modelled jointly for unbiased estimates of both effects. We show that present-day lensing data more »
- Publication Date:
- NSF-PAR ID:
- 10368044
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 514
- Issue:
- 2
- Page Range or eLocation-ID:
- p. 2876-2890
- ISSN:
- 0035-8711
- Publisher:
- Oxford University Press
- Sponsoring Org:
- National Science Foundation
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