Article

The UV‐Optical Galaxy Color‐Magnitude Diagram. III. Constraints on Evolution from the Blue to the Red Sequence

D. Christopher MartinCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Ted K. WyderCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125David SchiminovichDepartment of Astronomy, Columbia University, New York, NY 10027Tom A. BarlowCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Karl FörsterCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Peter G. FriedmanCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Patrick MorrisseyCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Susan G. NeffLaboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771Mark SeibertCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Todd SmallCalifornia Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125Barry Y. WelshSpace Sciences Laboratory, University of California at Berkeley, 601 Campbell Hall, Berkeley, CA 94720L. BianchiCenter for Astrophysical Sciences, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218J. DonasLaboratoire d’Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12, FranceTimothy M. HeckmanDepartment of Physics and Astronomy, The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218Young‐Wook LeeCenter for Space Astrophysics, Yonsei University, Seoul 120-749, KoreaBarry F. MadoreObservatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101Bruno MilliardLaboratoire d’Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12, FranceR. Michael RichDepartment of Physics and Astronomy, University of California, Los Angeles, CA 90095Alexander S. SzalayDepartment of Physics and Astronomy, The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218Sukyoung K. YiCenter for Space Astrophysics, Yonsei University, Seoul 120-749, Korea

2007en

ABI

Abstract

We introduce a new quantity, the mass flux density of galaxies evolving from the blue sequence to the red sequence. We propose a simple technique for constraining this mass flux using the volume-corrected number density in the extinction-corrected UV-optical color-magnitude distribution, the stellar age indexes Hδ_A and D_n(4000), and a simple prescription for spectral evolution using a quenched star formation history. We exploit the excellent separation of red and blue sequences in the NUV − r band Hess function. The final value we measure, ρ_T = 0.033 M_⊙ yr^(−1) Mpc^(−3), is strictly speaking an upper limit due to the possible contributions of bursting, composite, and extincted galaxies. However, it compares favorably with estimates of the average mass flux that we make based on the red luminosity function evolution derived from the DEEP2 and COMBO-17 surveys, ρ_R = +0.034 M_⊙ yr^(−1) Mpc^(−3). We find that the blue sequence mass has remained roughly constant since z = 1 (ρ_B ≃ 0.01 M_⊙ yr^(−1) Mpc^(−3)), but the average on-going star formation of ρ_(SF) ≃ 0.037 M_⊙ yr^(−1) Mpc^(−3) over 0 < z < 1 is balanced by mass flux off the blue sequence. We explore the nature of the galaxies in the transition zone with particular attention to the frequency and impact of active galactic nuclei (AGNs). The AGN fraction peaks in the transition zone. We find circumstantial, albeit weak evidence that the quench rates are higher in higher luminosity AGNs.\n

Identifiers

DOI: 10.1086/516639

Citations and references

Cited by 10 references

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