Is the core-cusp problem a matter of perspective: Jeans Anisotropic Modeling against numerical simulations
Abstract
Mock member stars for 28 dwarf galaxies are constructed from the cosmological Auriga simulation, which reflect the dynamical status of realistic stellar tracers. The axis-symmetric Jeans Anisotropic Multi-Gaussian Expansion (JAM) modeling is applied to 6,000 star particles for each system, to recover the underlying matter distribution. The stellar or dark matter component individually is poorly recovered, but the total profile is constrained more reasonably. The mass within the half-mass radius of tracers is recovered the tightest, and the mass between 200 and 300 pc, , is constrained ensemble unbiasedly, with a scatter of 0.167 dex. If using 2,000 particles and only line-of-sight velocities with typical errors, the scatter in is increased by 50%. Quiescent Sagittarius dSph-like systems and star-forming systems with strong outflows show distinct features, with mostly under-estimated for the former, and likely over-estimated for the latter. The biases correlate with the dynamical status, which is a result of contraction motions due to tidal effects in quiescent systems or galactic winds in star-forming systems, driving them out of equilibrium. After including Gaia DR3 proper motion errors, we find proper motions can be as useful as line-of-sight velocities for nearby systems at 60 kpc. By extrapolating the actual density profiles and the dynamical constraints down to scales below the resolution, we find the mass within 150 pc can be constrained ensemble unbiasedly, with a scatter of 0.255 dex. In the end, we show that the contraction of member stars in nearby systems is detectable based on Gaia DR3 proper motion errors.
Keywords
Cite
@article{arxiv.2206.12121,
title = {Is the core-cusp problem a matter of perspective: Jeans Anisotropic Modeling against numerical simulations},
author = {Wenting Wang and Ling Zhu and Zhaozhou Li and Yang Chen and Jiaxin Han and Feihong He and Xiaohu Yang and Yipeng Jing and Carlos Frenk and Jialu Nie and Hao Tian and Chao Liu and Yanan Cao and Xiaoqing Qiu and John Helly and Robert J. J. Grand and Facundo A. Gomez},
journal= {arXiv preprint arXiv:2206.12121},
year = {2022}
}
Comments
accepted by ApJ