2008/07/31 by F. Buitrago, Fernando Buitrago, Ignacio Trujillo +5 · 4 citations
Environmental Science · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #Plant Water Relations and Carbon Dynamics #astro-ph
paper · pdf · doi:10.1086/592836
5 pages, 2 figures, 2 tables, accepted by ApJ Letters, minor changes added to match the accepted version
arxiv created 2008/08/28 · openalex publication_date 2008/10/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We measure the sizes of 82 massive ( M ⩾ 10 11 M ☉ ) galaxies at 1.7 ⩽ z ⩽ 3 utilizing deep HST NICMOS data taken in the GOODS North and South fields. Our sample is almost an order of magnitude larger than previous studies at these redshifts, providing the first statistical study of massive galaxy sizes at z > 2, confirming the extreme compactness of these systems. We split our sample into disk-like ( n ⩽ 2) and spheroid-like ( n > 2) galaxies based on their Sérsic indices, and find that at a given stellar mass disk-like galaxies at z ∼ 2.3 are a factor of 2.6 ± 0.3 smaller than present-day equal-mass systems, and spheroid-like galaxies at the same redshifts are 4.3 ± 0.7 smaller than comparatively massive elliptical galaxies today. At z > 2 our results are compatible with both a leveling off, or a mild evolution in size. Furthermore, the high density (~2 × 10 10 M ☉ kpc −3 ) of massive galaxies at these redshifts, which are similar to present-day globular clusters, possibly makes any further evolution in sizes beyond z = 3 unlikely.