The Fundamental Plane of cluster spheroidal galaxies at z$\sim1.3$. Evidence for mass-dependent evolution

Understand

We present spectroscopic observations obtained at the {\it Large Binocular Telescope} in the field of the cluster XLSSJ0223-0436 at $z=1.22$.

• We confirm 12 spheroids cluster members and determine stellar velocity dispersion for 7 of them.
• We combine these data with those in the literature for clusters RXJ0848+4453 at $z=1.27$ (8 galaxies) and XMMJ2235-2557 at $z=1.39$ (7 galaxies) to determine the Fundamental Plane of cluster spheroids.
• We find that the FP at $z\sim1.3$ is offset and { rotated ($\sim3\sigma$)} with respect to the local FP.