%0 Generic %1 straatman2013substantial %A Straatman, Caroline M. S. %A Labbé, Ivo %A Spitler, Lee R. %A Allen, Rebecca %A Altieri, Bruno %A Brammer, Gabriel B. %A Dickinson, Mark %A van Dokkum, Pieter %A Inami, Hanae %A Glazebrook, Karl %A Kacprzak, Glenn G. %A Kawinwanichakij, Lalit %A Kelson, Daniel D. %A McCarthy, Patrick J. %A Mehrtens, Nicola %A Monson, Andy %A Murphy, David %A Papovich, Casey %A Persson, S. Eric %A Quadri, Ryan %A Rees, Glen %A Tomczak, Adam %A Tran, Kim-Vy H. %A Tilvi, Vithal %D 2013 %K galaxies high-z passive %T A substantial population of massive quiescent galaxies at z~4 from ZFOURGE %U http://arxiv.org/abs/1312.4952 %X We report the likely identification of a substantial population of massive M~10^11M_Sun galaxies at z~4 with suppressed star-formation rates (SFRs), selected on rest-frame optical to near-IR colors from the FourStar Galaxy Evolution Survey. The observed spectral energy distributions show pronounced breaks, sampled by a set of near-IR medium-bandwidth filters, resulting in tightly constrained photometric redshifts. Fitting stellar population models suggests large Balmer/4000AA breaks, relatively old stellar populations, large stellar masses and low SFRs, with a median specific SFR of 2.9+/-1.8 x 10^-11/yr. Ultradeep Herschel/PACS 100micron, 160micron and Spitzer/MIPS 24micron data reveal no dust-obscured SFR activity for 15/19 (79%) galaxies. Two far-IR detected galaxies are obscured QSOs. Stacking the far-IR undetected galaxies yields no detection, consistent with the SED fit, indicating independently that the average specific SFR is at least 10x smaller than of typical star-forming galaxies at z~4. Assuming all far-IR undetected galaxies are indeed quiescent, the volume density is 1.8+/-0.9 x 10^-5Mpc^-3 to a limit of log10M/M_Sun>10.6, which is 10x and 80x lower than at z = 2 and z = 0.1. They comprise a remarkably high fraction (~35%) of z~4 massive galaxies, suggesting that suppression of star-formation was efficient even at very high redshift. Given the average stellar age of 0.8Gyr and stellar mass of 0.8x10^11M_Sun, the galaxies likely started forming stars before z =5, with SFRs well in excess of 100M_Sun/yr, far exceeding that of similarly abundant UV-bright galaxies at z>4. This suggests that most of the star-formation in the progenitors of quiescent z~4 galaxies was obscured by dust.

@misc{straatman2013substantial, abstract = {We report the likely identification of a substantial population of massive M~10^11M_Sun galaxies at z~4 with suppressed star-formation rates (SFRs), selected on rest-frame optical to near-IR colors from the FourStar Galaxy Evolution Survey. The observed spectral energy distributions show pronounced breaks, sampled by a set of near-IR medium-bandwidth filters, resulting in tightly constrained photometric redshifts. Fitting stellar population models suggests large Balmer/4000AA breaks, relatively old stellar populations, large stellar masses and low SFRs, with a median specific SFR of 2.9+/-1.8 x 10^-11/yr. Ultradeep Herschel/PACS 100micron, 160micron and Spitzer/MIPS 24micron data reveal no dust-obscured SFR activity for 15/19 (79%) galaxies. Two far-IR detected galaxies are obscured QSOs. Stacking the far-IR undetected galaxies yields no detection, consistent with the SED fit, indicating independently that the average specific SFR is at least 10x smaller than of typical star-forming galaxies at z~4. Assuming all far-IR undetected galaxies are indeed quiescent, the volume density is 1.8+/-0.9 x 10^-5Mpc^-3 to a limit of log10M/M_Sun>10.6, which is 10x and 80x lower than at z = 2 and z = 0.1. They comprise a remarkably high fraction (~35%) of z~4 massive galaxies, suggesting that suppression of star-formation was efficient even at very high redshift. Given the average stellar age of 0.8Gyr and stellar mass of 0.8x10^11M_Sun, the galaxies likely started forming stars before z =5, with SFRs well in excess of 100M_Sun/yr, far exceeding that of similarly abundant UV-bright galaxies at z>4. This suggests that most of the star-formation in the progenitors of quiescent z~4 galaxies was obscured by dust.}, added-at = {2013-12-19T09:02:17.000+0100}, author = {Straatman, Caroline M. S. and Labbé, Ivo and Spitler, Lee R. and Allen, Rebecca and Altieri, Bruno and Brammer, Gabriel B. and Dickinson, Mark and van Dokkum, Pieter and Inami, Hanae and Glazebrook, Karl and Kacprzak, Glenn G. and Kawinwanichakij, Lalit and Kelson, Daniel D. and McCarthy, Patrick J. and Mehrtens, Nicola and Monson, Andy and Murphy, David and Papovich, Casey and Persson, S. Eric and Quadri, Ryan and Rees, Glen and Tomczak, Adam and Tran, Kim-Vy H. and Tilvi, Vithal}, biburl = {https://www.bibsonomy.org/bibtex/2e50adb5b9ba6f7b9ee80a8ecf5837da8/miki}, description = {[1312.4952] A substantial population of massive quiescent galaxies at z~4 from ZFOURGE}, interhash = {b28f5b7cc247a7f92fb3109b72d52948}, intrahash = {e50adb5b9ba6f7b9ee80a8ecf5837da8}, keywords = {galaxies high-z passive}, note = {cite arxiv:1312.4952Comment: 8 pages, 4 figures, 1 table, re-submitted to ApjL after second referee report}, timestamp = {2013-12-19T09:02:17.000+0100}, title = {A substantial population of massive quiescent galaxies at z~4 from ZFOURGE}, url = {http://arxiv.org/abs/1312.4952}, year = 2013 }