The VIMOS-VLT Deep Survey

The evolution of galaxy clustering per spectral type to z  1.5

¹ Laboratoire d'Astrophysique de Marseille, UMR 6110 CNRS, Université de Provence, BP 8, 13376 Marseille Cedex 12, France e-mail: baptiste.meneux@oamp.fr
² INAF - Osservatorio Astronomico di Brera, via Bianchi 46, 23807 Merate, Italy
³ INAF - Osservatorio Astronomico di Bologna, via Ranzani,1, 40127 Bologna, Italy
⁴ Università di Bologna, Dipartimento di Astronomia, via Ranzani, 1, 40127 Bologna, Italy
⁵ INAF - Osservatorio Astronomico di Brera, via Brera 28, Milan, Italy
⁶ Centre de Physique Theorique, UMR 6207 CNRS, Université de Provence, case 907, 13288 Marseille, France
⁷ Institut d'Astrophysique de Paris, Université Pierre et Marie Curie, UMR 7095, 98 bis Bvd Arago, 75014 Paris, France
⁸ Observatoire de Paris, LERMA, 61 Avenue de l'Observatoire, 75014 Paris, France
⁹ INAF – IASF Milano, via Bassini 15, 20133 Milano, Italy
¹⁰ Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (UMR 5572), 14 avenue E. Belin, 31400 Toulouse, France
¹¹ INAF – Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone, Italy
¹² IRA – INAF, via Gobetti 101, 40129 Bologna, Italy
¹³ INAF – Osservatorio Astronomico di Capodimonte, via Moiariello 16, 80131 Napoli, Italy
¹⁴ Max Planck Institut fur Astrophysik, 85741 Garching, Germany
¹⁵ School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
¹⁶ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen, Germany
¹⁷ Integral Science Data Centre, ch. d'Écogia 16, 1290 Versoix, Switzerland
¹⁸ Geneva Observatory, ch. des Maillettes 51, 1290 Sauverny, Switzerland

Received: 22 November 2005
Accepted: 11 February 2006

Abstract

We measure the evolution of clustering for galaxies with different spectral types from 6495 galaxies with and measured spectroscopic redshifts in the first epoch VIMOS-VLT Deep Survey (VVDS). We divide our sample into four classes, based on the fit of well-defined galaxy spectral energy distributions on observed multi-color data. We measure the projected correlation function and estimate the best-fit parameters for a power-law real-space correlation function . We find the clustering of early-spectral-type galaxies to be markedly stronger than that of late-type galaxies at all redshifts up to . At , early-type galaxies display a correlation length  h^-1 Mpc, while late types have  h^-1 Mpc. For the latest class of star-forming blue galaxies, we are able to push our clustering measurement to an effective redshift , for luminous galaxies (). The clustering of these objects increases up to  h^-1 Mpc for . The relative bias between early- and late-type galaxies within our magnitude-limited survey remains approximately constant with from to . This result is in agrement with the local findings and fairly robust against different way of classifying red and blue galaxies. When compared to the expected linear growth of mass fluctuations, a natural interpretation of these observations is that: (a) the assembly of massive early type galaxies is already mostly complete in the densest dark matter halos at ; (b) luminous late-type galaxies are located in higher-density, more clustered regions of the Universe at than their local low luminous counterpart, indicating that star formation activity is progressively increasing, going back in time, in the higher-density peaks that today are mostly dominated by old galaxies.