The evolution of the scatter of the cosmic average color-magnitude relation: demonstrating consistency with the ongoing formation of elliptical galaxies

Christine Ruhland, Eric F. Bell, Boris Haeussler, Edward N. Taylor, Marco Barden, Daniel H. McIntosh

    Research output: Contribution to journalArticlepeer-review

    24 Citations (Scopus)
    126 Downloads (Pure)

    Abstract

    We present first measurements of the evolution of the scatter of the cosmic average early-type galaxy color-magnitude relation (CMR) from z = 1 to the present day, finding that it is consistent with models in which galaxies are constantly being added to the red sequence through truncation of star formation in blue cloud galaxies. We used a sample of over 700 red sequence, structurally selected early-type galaxies (defined to have Sersic index > 2.5) with redshifts 0 < z < 1 taken from the Extended Chandra Deep Field South (173 galaxies) and the Sloan Digital Sky Survey (550 galaxies), constructing rest-frame U-V colors accurate to < 0.04 mag. We find that the scatter of the CMR of cosmic average early-type galaxies is similar to 0.1 mag in rest-frame U-V color at 0.05 < z < 0.75, and somewhat higher at z = 1. We compared these observations with a model in which new red-sequence galaxies are being constantly added at the rate required to match the observed number density evolution, and found that this model predicts the correct CMR scatter and its evolution. Furthermore, this model predicts approximately the correct number density of "blue spheroids"-structurally early-type galaxies with blue colors-albeit with considerable model dependence. Thus, we conclude that both the evolution of the number density and colors of the early-type galaxy population paint a consistent picture in which the early-type galaxy population grows significantly between z = 1 and the present day through the quenching of star formation in blue cloud galaxies.

    Original languageEnglish
    Pages (from-to)1058-1069
    Number of pages12
    JournalThe Astrophysical Journal
    Volume695
    Issue number2
    DOIs
    Publication statusPublished - 20 Apr 2009

    Keywords

    • galaxies: elliptical and lenticular, cD
    • galaxies: evolution
    • galaxies: general
    • galaxies: stellar content
    • surveys
    • ORIGINS DEEP SURVEY
    • GOODS-SOUTH FIELD
    • DIGITAL SKY SURVEY
    • LUMINOSITY FUNCTION
    • VLT/FORS2 SPECTROSCOPY
    • STELLAR MASS
    • REDSHIFT GALAXIES
    • NEARBY CLUSTERS
    • COMBO-17 SURVEY
    • STAR-FORMATION

    Fingerprint

    Dive into the research topics of 'The evolution of the scatter of the cosmic average color-magnitude relation: demonstrating consistency with the ongoing formation of elliptical galaxies'. Together they form a unique fingerprint.

    Cite this