The massive relic galaxy NGC 1277 is dark matter deficient. From dynamical models of integral-field stellar kinematics out to five effective radii

• Published in: arXiv.org 2023-06
• Main Authors: Comerón, Sébastien, Trujillo, Ignacio, Cappellari, Michele, Buitrago, Fernando, Garduño, Luis E, Zaragoza-Cardiel, Javier, Zinchenko, Igor A, Lara-López, Maritza A, Ferré-Mateu, Anna, Dib, Sami
• Format: Article
• Language: English
• Subjects: Astronomical models; Confidence intervals; Dark matter; Deposition; Dynamic models; Friction reduction; Galactic clusters; Galaxies; Stars & galaxies; Stellar kinematics
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2303.11360

According to the \(\Lambda\)CDM cosmology, present-day galaxies with stellar masses \(M_\star>10^{11} {\rm M}_\odot\) should contain a sizable fraction of dark matter within their stellar body. Models indicate that in massive early-type galaxies (ETGs) dark matter should account for \(\sim60\%\) of the dynamical mass within five effective radii (\(5 R_{\rm e}\)). Most massive ETGs have been shaped through a two-phase process: the rapid growth of a compact core was followed by the accretion of an extended envelope through mergers. The exceedingly rare galaxies that have avoided the second phase, the so-called relic galaxies, are thought to be the frozen remains of the massive ETG population at \(z\gtrsim2\). The best relic galaxy candidate discovered to date is NGC 1277, in the Perseus cluster. We used deep integral field GCMS data to revisit NGC 1277 out to an unprecedented radius of 6 kpc (corresponding to \(5 R_{\rm e}\)). By using Jeans anisotropic modelling we find a negligible dark matter fraction within \(5 R_{\rm e}\) (\(f_{\rm DM}(5 R_{\rm e})