REVERSAL OF FORTUNE: CONFIRMATION OF AN INCREASING STAR FORMATION-DENSITY RELATION IN A CLUSTER AT z=1.62 uri icon

abstract

  • We measure the rest-frame colors (dust-corrected), infrared luminosities, star formation rates, and stellar masses of 92 galaxies in a Spitzer-selected cluster at z = 1.62. By fitting spectral energy distributions (SEDs) to 10-band photometry (0.4m< obs < 8m) and measuring 24m fluxes for the 12 spectroscopically confirmed and 80 photometrically selected members, we discover an exceptionally high level of star formation in the cluster core of 1700M yr-1 Mpc -2. The cluster galaxies define a strong blue sequence in (U-V ) color and span a range in color. We identify 17 members with LIR > 1011 L, and these IR luminous members follow the same trend of increasing star formation with stellar mass that is observed in the field at z 2. Using rates derived from both the 24m imaging and SED fitting, we find that the relative fraction of star-forming members triples from the lowest to highest galaxy density regions; e.g., the IR luminous fraction increases from 8% at 10 gal Mpc-2 to 25% at 100 gal Mpc-2. The observed increase is a reversal of the well-documented trend at z < 1 and signals that we have reached the epoch when massive cluster galaxies are still forming a substantial fraction of their stars. 2010. The American Astronomical Society. All rights reserved.

published proceedings

  • ASTROPHYSICAL JOURNAL LETTERS

author list (cited authors)

  • Tran, K., Papovich, C., Saintonge, A., Brodwin, M., Dunlop, J. S., Farrah, D., ... Willmer, C.

citation count

  • 197

complete list of authors

  • Tran, Kim-Vy H||Papovich, Casey||Saintonge, Amelie||Brodwin, Mark||Dunlop, James S||Farrah, Duncan||Finkelstein, Keely D||Finkelstein, Steven L||Lotz, Jennifer||McLure, Ross J||Momcheva, Ivelina||Willmer, Christopher NA

publication date

  • August 2010