Hubble Space Telescope and Spitzer Imaging of red and blue galaxies at z ~ 2.5: a correlation between size and star formation activity from compact quiescent galaxies to extended star-forming galaxies

Toft, S.
van Dokkum, P.
Franx, M.
Labbe, I.
Förster Schreiber, N. M.
Wuyts, S.
Webb, T.
Rudnick, G.
Zirm, A.
Kriek, M.
van der Werf, P.
Blakeslee, J. P.
Illingworth, G.
Rix, H. W.
Papovich, C.
Moorwood, A.

Publication date

January 2007

Abstract

We present HST NICMOS+ACS and Spitzer IRAC+MIPS observations of 41 galaxies at 2<z<3.5 in the FIRES MS 1054 field with red and blue rest-frame optical colors. About half of the galaxies are very compact (effective radii re<1 kpc) at rest-frame optical wavelengths; the others are extended (1 kpc<re<10 kpc). For reference, 1 kpc corresponds to 0.12" at z=2.5 in the adopted cosmology. We separate actively star-forming galaxies from quiescent galaxies by modeling their rest-frame UV-NIR SEDs. The star-forming galaxies span the full range of sizes, while the quiescent galaxies all have re<2 kpc. In the redshift range where MIPS 24 mum imaging is a sensitive probe of reradiated dust emission (z<2.5), the 24 mum fluxes confirm that the light of th...