Massive Galaxy Halos Contain Less Inner Dark Matter Than Predicted

@misc{wang2026massive,
  title = {{Massive Galaxy Halos Contain Less Inner Dark Matter Than Predicted}},
  author = {Yu-Chen Wang and Yingjie Peng and Xiaohu Yang and Luis C. Ho and Dingyi Zhao and Jing Dou and Hao Fu and Zeyu Gao and Qiusheng Gu and Fangzhou Jiang and Yukun Liu and Roberto Maiolino and Houjun Mo and Canpo Su and Bitao Wang and Kai Wang and Bingxiao Xu and Feng Yuan and Kunyao Zhao and Xingye Zhu},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.19132},
  eprint = {2609.19132},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.19132},
}

TY  - UNPB
TI  - Massive Galaxy Halos Contain Less Inner Dark Matter Than Predicted
AU  - Yu-Chen Wang
AU  - Yingjie Peng
AU  - Xiaohu Yang
AU  - Luis C. Ho
AU  - Dingyi Zhao
AU  - Jing Dou
AU  - Hao Fu
AU  - Zeyu Gao
AU  - Qiusheng Gu
AU  - Fangzhou Jiang
AU  - Yukun Liu
AU  - Roberto Maiolino
AU  - Houjun Mo
AU  - Canpo Su
AU  - Bitao Wang
AU  - Kai Wang
AU  - Bingxiao Xu
AU  - Feng Yuan
AU  - Kunyao Zhao
AU  - Xingye Zhu
PY  - 2026
DA  - 2026/09/16
PB  - arXiv
DO  - 10.48550/arxiv.2609.19132
UR  - https://arxiv.org/abs/2609.19132
AB  - The mass profiles of galaxy halos encode how baryons reshape dark matter distribution, yet direct observational constraints across the full radial range remain scarce. Here we combine stellar kinematics from MaNGA, H I dynamical measurements from ALFALFA, and independently calibrated halo masses of SDSS groups to statistically reconstruct the mass distribution of central galaxies over nearly two orders of magnitude in radius. We demonstrate that H I data alone do not provide reliable total halo mass estimates, necessitating an independent group-based halo-mass scale. Compared to the IllustrisTNG and EAGLE simulations, the observational profiles of low-mass halos are broadly consistent; in contrast, massive observed halos exhibit systematically lower dynamical masses at the H I radius, lower inner dark-matter masses, and lower central dark-matter fractions (about 4σ difference in units of population scatter) at fixed total halo mass. After subtracting baryonic contributions, the inferred dark-matter profiles remain broadly consistent with an NFW form, but with lower effective concentrations than predicted for massive halos. These results suggest that the inner dark-matter content of massive halos has been reduced more significantly than predicted by current hydrodynamical simulations, plausibly due to long-term baryonic halo heating in massive systems.
ER  -