Massive evolved galaxies revealed ^*

¹ INAF - Osservatorio Astronomico di Brera, Via Brera 28, 20121 Milano, Italy e-mail: [saracco, marcella]@merate.mi.astro.it; [paola, rdc]@brera.mi.astro.it
² IRA-CNR, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: filippo@arcetri.astro.it
³ Universitäts-Sternwarte München, Scheiner Str. 1, 81679 München, Germany e-mail: [bender, feulner, hopp, maraston]@usm.uni-muenchen.de
⁴ University of Texas at Austin, Austin, Texas 78712, USA e-mail: drory@astro.as.utexas.edu
⁵ Centro Galileo Galilei, La Palma, Spain e-mail: ghinassi@tng.iac.es

Corresponding author: P. Saracco, saracco@merate.mi.astro.it

Received: 19 September 2002
Accepted: 8 November 2002

Abstract

We present the results of TNG near-IR low resolution spectroscopy of two (S7F5_254 and S7F5_45) sources belonging to a complete sample of 15 EROs with K'  and   selected from the MUNICS Survey. Both the spectra show a sharp drop in the continuum which can be ascribed only to the Balmer break. This places them at 1.2 . Their rest-frame K-band absolute magnitude is (L ). The comparison of the spectra and the photometric data with a grid of synthetic template spectra provides a redshift for S7F5_254 and for S7F5_45. The resulting lower limits to their stellar mass are and . The minimum age of the last burst of star formation in S7F5_254 is 3.5 Gyr while it is 0.5 Gyr in S7F5_45 implying a minimum formation redshift and for the two EROs respectively.