The Galaxy Mass Assembly ultra-deep Spectroscopic Survey samples a part of the CDFS to unprecedented depth. The resulting distribution of 150 z>1.4 redshifts reveals a significant peak at z = 1.6, part of a larger overdensity found at this redshift. The 42 spectroscopic members of this structure, called Cl 0332-2742, form an overdensity in redshift of a factor 11±3 and have a velocity dispersion of 450 km s^{-1}. We derive a total mass for Cl 0332-2742 of ˜ 7 × 10^{14} M_sun. The colours of its early-type galaxies are consistent with a theoretical red sequence of galaxies with stars formed at z=3.0. In addition, there are more massive, passive and older, but less star forming galaxies in CL 0332-2742 than in the field. We conclude that this structure is a cluster under assembly at z=1.6.
Kurk J., Cimatti A., Zamorani G., Halliday C., Mignoli M., Pozzetti L., et al. (2008). A Spectroscopic Study of a z=1.6 Galaxy Overdensity in the GMASS Field. SAN FRANCISCO : Astronomical Society of the Pacific.
A Spectroscopic Study of a z=1.6 Galaxy Overdensity in the GMASS Field
CIMATTI, ANDREA;
2008
Abstract
The Galaxy Mass Assembly ultra-deep Spectroscopic Survey samples a part of the CDFS to unprecedented depth. The resulting distribution of 150 z>1.4 redshifts reveals a significant peak at z = 1.6, part of a larger overdensity found at this redshift. The 42 spectroscopic members of this structure, called Cl 0332-2742, form an overdensity in redshift of a factor 11±3 and have a velocity dispersion of 450 km s^{-1}. We derive a total mass for Cl 0332-2742 of ˜ 7 × 10^{14} M_sun. The colours of its early-type galaxies are consistent with a theoretical red sequence of galaxies with stars formed at z=3.0. In addition, there are more massive, passive and older, but less star forming galaxies in CL 0332-2742 than in the field. We conclude that this structure is a cluster under assembly at z=1.6.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
