Age, metallicity and star formation history of spheroidal galaxies in cluster at z~1.2

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We present the analysis, based on spectra collected at the Large Binocular Telescope, of the stellar populations in seven spheroidal galaxies in the cluster XLSSJ0223 at $z$$\sim$1.22.

• The aim is to constrain the epoch of their formation and their star formation history.
• Using absorption line strenghts and full spectral fitting, we derive for the stellar populations of the seven spheroids a median age <Age>=2.4$\pm$0.6 Gyr, corresponding to a median formation redshift $<$$z_f$$>$$\sim2.6_{-0.5}^{+0.7}$ (lookback time = 11$_{-1.0}^{+0.6}$ Gyr).
• We find a significant scatter in age, showing that massive spheroids, at least in our targeted cluster, are not coeval.