Detection of evolved high-redshift galaxies in deep NICMOS VLT images

被引:48
作者
Benítez, N
Broadhurst, T
Bouwens, R
Silk, J
Rosati, P
机构
[1] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[2] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[3] Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA
[4] European So Observ, D-85749 Garching, Germany
关键词
galaxies; evolution;
D O I
10.1086/311975
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
A substantial population of high-redshift, early-type galaxies is detected in very deep UBVRIJHK images. Four elliptical profile galaxies are identified in the redshift range 1 < z < 2, with very red spectral energy distributions implying ages of greater than or similar to 2 Gyr for standard passive evolution. We also find later type IR-luminous galaxies at similarly high redshift (10 objects with z > 1, H < 25), with weak UV emission implying single-burst ages of greater than or similar to 1 Gyr. The number and luminosity densities of these galaxies are comparable to the local E/S0-Sbc populations for Omega(m) > 0.2, suggesting that the major fraction of luminous Hubble sequence galaxies has evolved little since z similar to 2. A highly complete photometric redshift distribution is constructed to H = 25 (69 galaxies) that shows a broad spread of redshift, peaking at z similar to 1.5, in reasonable agreement with some analyses of the Hubble Deep Field. Four "dropout" galaxies are detected at z approximate to 3.8 and are compact in the IR, similar to 0.5 kpc h(-1) at rest frame 3500 Angstrom. No example of a blue IR-luminous elliptical galaxy is found, thus restricting the star formation epoch of elliptical galaxies to z greater than or equal to 5-10 for a standard initial mass function and modest extinction.
引用
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页码:L65 / L68
页数:4
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