Selection and photometric properties of K+A galaxies

Alejandro D. Quintero, David W. Hogg, Michael R. Blanton, David J. Schlegel, Daniel J. Eisenstein, James E. Gunn, J. Brinkmann, Masataka Fukugita, Karl Glazebrook, Tomotsugu Goto

    Research output: Contribution to journalArticle

    Abstract

    Two different simple measurements of galaxy star formation rate with different timescales are compared empirically on 156,395 fiber spectra of galaxies with r < 17.77 mag taken from the Sloan Digital Sky Survey in the redshift range 0.05 < z < 0.20: a ratio A/K found by fitting a linear sum of an average old stellar population spectrum (K) and average A star spectrum (A) to the galaxy spectrum, and the equivalent width (EW) of the Hα emission line. The two measures are strongly correlated, but there is a small, clearly separated population of outliers from the median correlation that display excess A/K relative to Hα EW. These "K+A" (or "E+A") galaxies must have dramatically decreased their star formation rates over the last ∼1 Gyr. The K+A luminosity distribution is similar to that of the total galaxy population. The K+A population appears to be bulge-dominated, but bluer and with higher surface brightness than normal bulge-dominated galaxies; it appears that K+A galaxies will fade with time into normal bulge-dominated galaxies. The inferred rate density for K+A galaxy formation is ∼10-4 h3 Mpc-3 Gyr -1 at redshift z ∼ 0.1. These events are taking place in the field; the K+A galaxies found in this study do not primarily lie in the high-density environments or clusters typical of bulge-dominated populations.

    Original languageEnglish (US)
    Pages (from-to)190-199
    Number of pages10
    JournalAstrophysical Journal
    Volume602
    Issue number1 I
    DOIs
    StatePublished - Feb 10 2004

    Fingerprint

    galaxies
    outlier
    star formation rate
    timescale
    A stars
    galactic evolution
    rate
    brightness
    luminosity
    fibers
    distribution
    fibre

    Keywords

    • Galaxies: clusters: general
    • Galaxies: evolution
    • Galaxies: fundamental parameters
    • Galaxies: statistics
    • Galaxies: stellar content
    • Stars: formation

    ASJC Scopus subject areas

    • Space and Planetary Science

    Cite this

    Quintero, A. D., Hogg, D. W., Blanton, M. R., Schlegel, D. J., Eisenstein, D. J., Gunn, J. E., ... Goto, T. (2004). Selection and photometric properties of K+A galaxies. Astrophysical Journal, 602(1 I), 190-199. https://doi.org/10.1086/380601

    Selection and photometric properties of K+A galaxies. / Quintero, Alejandro D.; Hogg, David W.; Blanton, Michael R.; Schlegel, David J.; Eisenstein, Daniel J.; Gunn, James E.; Brinkmann, J.; Fukugita, Masataka; Glazebrook, Karl; Goto, Tomotsugu.

    In: Astrophysical Journal, Vol. 602, No. 1 I, 10.02.2004, p. 190-199.

    Research output: Contribution to journalArticle

    Quintero, AD, Hogg, DW, Blanton, MR, Schlegel, DJ, Eisenstein, DJ, Gunn, JE, Brinkmann, J, Fukugita, M, Glazebrook, K & Goto, T 2004, 'Selection and photometric properties of K+A galaxies', Astrophysical Journal, vol. 602, no. 1 I, pp. 190-199. https://doi.org/10.1086/380601
    Quintero AD, Hogg DW, Blanton MR, Schlegel DJ, Eisenstein DJ, Gunn JE et al. Selection and photometric properties of K+A galaxies. Astrophysical Journal. 2004 Feb 10;602(1 I):190-199. https://doi.org/10.1086/380601
    Quintero, Alejandro D. ; Hogg, David W. ; Blanton, Michael R. ; Schlegel, David J. ; Eisenstein, Daniel J. ; Gunn, James E. ; Brinkmann, J. ; Fukugita, Masataka ; Glazebrook, Karl ; Goto, Tomotsugu. / Selection and photometric properties of K+A galaxies. In: Astrophysical Journal. 2004 ; Vol. 602, No. 1 I. pp. 190-199.
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