Infrared color selection of massive galaxies at z > 3



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Pérez González, Pablo Guillermo and otros, ... (2016) Infrared color selection of massive galaxies at z > 3. Astrophysical journal, 816 (2). ISSN 0004-637X

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We introduce a new color selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H160 (H) and Infrared Array Camera (IRAC) 4.5 μm bands, specifically H – [4.5] > 2.25 mag. These galaxies, called "HIEROs," include two major populations that can be separated with an additional J − H color. The populations are massive and dusty star-forming galaxies at z > 3 (JH – blue) and extremely dusty galaxies at z ≲ 3 (JH – red). The 350 arcmin^2 of the GOODS-North and GOODS-South fields with the deepest Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) near-infrared and IRAC data contain as many as 285 HIEROs down to [4.5] < 24 mag. Inclusion of the most extreme HIEROs, not even detected in the H band, makes this selection particularly complete for the identification of massive high-redshift galaxies. We focus here primarily on JH – blue(z>3) HIEROs, which have a median photometric redshift <z> ~ 4.4 and stellar mass M_* ~ 10^10.6 M_⨀ and are much fainter in the rest-frame UV than similarly massive Lyman-break galaxies (LBGs). Their star formation rates (SFRs), derived from their stacked infrared spectral energy distributions (SEDs), reach ~240 M_⨀ yr^-1, leading to a specific SFR, sSFR ≡ SFR/M_* ~ 4.2 Gyr^-1, suggesting that the sSFRs for massive galaxies continue to grow at z > 2 but at a lower growth rate than from z = 0 to z = 2. With a median half-light radius of 2 kpc, including ~20% as compact as quiescent (QS) galaxies at similar redshifts, JH – blue HIEROs represent perfect star-forming progenitors of the most massive M_* ≳ 10^11.2 M_⨀) compact QS galaxies at z ~ 3 and have the right number density. HIEROs make up ~60% of all galaxies with M_* > 10^10.5 M_⨀ identified at z > 3 from their photometric redshifts. This is five times more than LBGs with nearly no overlap between the two populations. While HIEROs make up 15%–25% of the total SFR density at z ~ 4 –5, they completely dominate the SFR density taking place in M_* > 10^10.5 M_⨀ galaxies, and HIEROs are therefore crucial to understanding the very early phase of massive galaxy formation.

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© 2016. The American Astronomical Society. All rights reserved. artículo firmado por 32 autores. This work is based on observations taken by the CANDELS Multi-Cycle Treasury Program and the 3D-HST Treasury Program with the NASA/ESA HST, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. The research leading to these results has received funding from the European Union Seventh Framework Program (FP7/2007-2013) under grant agreement No. 312725 (ASTRODEEP). T.W. acknowledges support for this work from the National Natural Science Foundation of China under grants 11303014, 11133001, and 11273015. P.G. acknowledges support from Spanish MINECO grant AYA2012-31277.

Uncontrolled Keywords:Star-forming galaxies; Similar-to 4; Spectral energy-distributions; Extragalactic legacy survey; Rest-frame ultraviolet; Survey. survey design; Extremely red objects; Quasar host galaxies; Lyman break galaxies; Goods-music sample
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:35791
Deposited On:18 Feb 2016 14:59
Last Modified:10 Dec 2018 15:05

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