Dark matter measurements combining stellar and HI kinematics: 30% $1-\sigma$ outliers with low dark matter content at $5R_\mathrm{e}$ - Archive ouverte HAL Accéder directement au contenu
Pré-Publication, Document De Travail Année : 2024

Dark matter measurements combining stellar and HI kinematics: 30% $1-\sigma$ outliers with low dark matter content at $5R_\mathrm{e}$

Meng Yang
  • Fonction : Auteur
Ling Zhu
  • Fonction : Auteur
Yu Lei
  • Fonction : Auteur
Nicholas Boardman
  • Fonction : Auteur
Anne-Marie Weijman
  • Fonction : Auteur
Raffaella Morganti
  • Fonction : Auteur
Tom Oosterloo
  • Fonction : Auteur

Résumé

We construct the Schwarzschild dynamical models for 11 early-type galaxies with the SAURON and Mitchell stellar IFUs out to $2-4 R_\mathrm{e}$, and construct dynamical models with combined stellar and HI kinematics for a subsample of 4 galaxies with HI velocity fields out to $10 R_\mathrm{e}$ obtained from the Westerbork Synthesis Radio Telescope, thus robustly obtaining the dark matter content out to large radii for these galaxies. Adopting a generalised-NFW dark matter profile, we measure an NFW-like density cusp in the dark matter inner slopes for all sample galaxies, with a mean value of $1.00\pm0.04$ (rms scatter $0.15$). The mean dark matter fraction for the sample is $0.2$ within $1 R_\mathrm{e}$, and increases to $0.4$ at $2 R_\mathrm{e}$, and $0.6$ at $5 R_\mathrm{e}$. The dark matter fractions within $1 R_\mathrm{e}$ of these galaxies are systematically lower than the predictions of both the TNG-100 and EAGLE simulations. For the dark matter fractions within $2 R_\mathrm{e}$ and $5 R_\mathrm{e}$, 40% and 70% galaxies are $1-\sigma$ consistent with either the TNG-100 or the EAGLE predictions, while the remaining 60% and 30% galaxies lie below the $1-\sigma$ region. Combined with 36 galaxies with dark matter fractions measured out to $5 R_\mathrm{e}$ in the literature, about 10% of these 47 galaxies lie below the $3-\sigma$ region of the TNG-100 or EAGLE predictions.

Dates et versions

hal-04455646 , version 1 (13-02-2024)

Identifiants

Citer

Meng Yang, Ling Zhu, Yu Lei, Nicholas Boardman, Anne-Marie Weijman, et al.. Dark matter measurements combining stellar and HI kinematics: 30% $1-\sigma$ outliers with low dark matter content at $5R_\mathrm{e}$. 2024. ⟨hal-04455646⟩
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