We present near-infrared VLT-UT1+ISAAC spectroscopy of a sample of 9
extremely red galaxies (ERGs) with R-K>5 and K<19.0. Neither strong emission
lines (F_lim<1-5 10^{-16} erg s^{-1}cm^{-2}) nor continuum breaks are detected.
From near-infrared spectrophotometry, complemented with broad-band optical
and near-IR photometry, we estimate ``spectro-photometric'' redshifts to be in
the range of 0.8<z_sphot<1.8. We derive upper limits on the star formation
rates in range of SFR<6-30h_50^{-2} M_solar yr^{-1}. Two of the observed ERGs
are dusty starburst candidates because they require strong dust reddening to
reproduce their global spectral energy distributions. The other ERGs are
consistent with being dustless old passively evolved spheroidals at z>0.8. We
discuss the general implications of our findings in relation with the problem
of the formation of early type galaxies.Comment: 6 pages, 2 figures. Astronomy & Astrophysics (Letters), in pres
