EXPANDED SEARCH FOR z {approx} 10 GALAXIES FROM HUDF09, ERS, AND CANDELS DATA: EVIDENCE FOR ACCELERATED EVOLUTION AT z > 8?

Journal Article · Wed Feb 01 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/745/2/110· OSTI ID:22011931

Oesch, P A; Illingworth, G D; Gonzalez, V; Magee, D ^[1]; Bouwens, R J; Labbe, I; Franx, M ^[2]; Trenti, M ^[3]; Carollo, C M ^[4]

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1. UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)
2. Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)
3. Center for Astrophysics and Space Astronomy, University of Colorado, 389-UCB, Boulder, CO 80309 (United States)
4. Institute for Astronomy, ETH Zurich, 8092 Zurich (Switzerland)

We search for z {approx} 10 galaxies over {approx}160 arcmin{sup 2} of Wide-Field Camera 3 (WFC3)/IR data in the Chandra Deep Field South, using the public HUDF09, Early Release Science, and CANDELS surveys, that reach to 5{sigma} depths ranging from 26.9 to 29.4 in H{sub 160} AB mag. z {approx}> 9.5 galaxy candidates are identified via J{sub 125} - H{sub 160} > 1.2 colors and non-detections in any band blueward of J{sub 125}. Spitzer Infrared Array Camera (IRAC) photometry is key for separating the genuine high-z candidates from intermediate-redshift (z {approx} 2-4) galaxies with evolved or heavily dust obscured stellar populations. After removing 16 sources of intermediate brightness (H{sub 160} {approx} 24-26 mag) with strong IRAC detections, we only find one plausible z {approx} 10 galaxy candidate in the whole data set, previously reported in Bouwens et al.. The newer data cover a 3 Multiplication-Sign larger area and provide much stronger constraints on the evolution of the UV luminosity function (LF). If the evolution of the z {approx} 4-8 LFs is extrapolated to z {approx} 10, six z {approx} 10 galaxies are expected in our data. The detection of only one source suggests that the UV LF evolves at an accelerated rate before z {approx} 8. The luminosity density is found to increase by more than an order of magnitude in only 170 Myr from z {approx} 10 to z {approx} 8. This increase is {>=}4 Multiplication-Sign larger than expected from the lower redshift extrapolation of the UV LF. We are thus likely witnessing the first rapid buildup of galaxies in the heart of cosmic reionization. Future deep Hubble Space Telescope WFC3/IR data, reaching to well beyond 29 mag, can enable a more robust quantification of the accelerated evolution around z {approx} 10.

• OSTI ID: 22011931
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 745; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BRIGHTNESS
DUSTS
GALACTIC EVOLUTION
GALAXIES
LUMINOSITY
PHOTOMETRY
RED SHIFT
STARS
TELESCOPES