The central bulges of galaxies at 0.3 < z < 1.0

Domínguez-Palmero, L.; Balcells, M.; Prieto, M.; Cristóbal-Hornillos, D.; Erwin, P.; Eliche-Moral, C.
Bibliographical reference

II International GTC Workshop: Science with GTC 1st-light Instruments and the LMT (Eds. A. M. Hidalgo-Gámez, J. J. González, J. M. Rodríguez Espinosa, and S. Torres-Peimbert) Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) Vol. 24, pp. 233-234 (2005) (http://www.astroscu.unam.mx/~rmaa/)

Advertised on:
12
2005
Number of authors
6
IAC number of authors
0
Citations
0
Refereed citations
0
Description
We have studied the colors of the bulge component of 133 galaxies from the HST Groth Strip Survey (Groth et al. 1994), covering redshifts 0.3 < z < 1.0. We selected all objects apparent radii R > 1.4'', and inclination above 50 degrees in order to avoid reddening from dust in the disk on one side of the bulges. We find that, as in the Local Universe, the minor axis color profiles are negative (bluer outside), and fairly gentle, indicating that bulge colors are not distinctly different from disk colors. In most cases, dust bands are the most important morphological structure in the color maps. In a subsample of 76 galaxies with spectroscopic redshifts, we analyze central rest-frame colors using K-corrections. Bulge colors do not globally become bluer at higher redshifts. This suggests that there were 'old' bulges at z = 0.8. The color-magnitude distribution of intermediate-z bulges is steeper than that of bulges in the Local Universe. The most massive bulges are as red as local bulges, while the remainder are significantly bluer, a possible sign of late bulge formation.