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

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 body. Models indicate that in massive early-type (ETGs) account for $\sim60\%$ dynamical mass five effective radii ($5 R_{\rm e}$). Most ETGs have been shaped through two-phase process: rapid growth compact core was followed by accretion an extended envelope mergers. The exceedingly rare avoided second phase, so-called relic galaxies, are thought be frozen remains ETG population at $z\gtrsim2$. best galaxy candidate discovered date is NGC 1277, Perseus cluster. We used deep integral field GCMS data revisit 1277 out unprecedented radius 6 kpc (corresponding $5 By using Jeans anisotropic modelling we find negligible e}$ ($f_{\rm DM}(5 e})<0.05$; two-sigma confidence level), which tension expectation. Since lack would reduce friction and prevent envelope, propose lost its very early or it deficient ab initio. discuss our discovery framework recent proposals suggesting some may result from stripping as they fell interacted clusters. Alternatively, might born high-velocity collision gas-rich proto-galactic fragments, where left behind disc dissipative baryons. speculate relative velocities $\approx2000 km/s}$ required latter process happen were possible progenitors rich