THE ABUNDANCE OF STAR-FORMING GALAXIES IN THE REDSHIFT RANGE 8.5-12: NEW RESULTS FROM THE 2012 HUBBLE ULTRA DEEP FIELD CAMPAIGN

Journal Article · Sun Jan 20 04:00:00 EST 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/763/1/L7· OSTI ID:22078329

Ellis, Richard S; Schenker, Matthew A ^[1]; McLure, Ross J; Dunlop, James S; Bowler, Rebecca A. A.; Rogers, Alexander B; Curtis-Lake, Emma; Cirasuolo, Michele ^[2]; Robertson, Brant E; Schneider, Evan; Stark, Daniel P ^[3]; Ono, Yoshiaki; Ouchi, Masami ^[4]; Koekemoer, Anton ^[5]; Charlot, Stephane ^[6]

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1. Department of Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States)
2. Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom)
3. Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
4. Institute for Cosmic Ray Research, University of Tokyo, Kashiwa City, Chiba 277-8582 (Japan)
5. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
6. UPMC-CNRS, UMR7095, Institut d'Astrophysique de Paris, F-75014 Paris (France)

We present the results of the deepest search to date for star-forming galaxies beyond a redshift z {approx_equal} 8.5 utilizing a new sequence of near-infrared Wide-Field Camera 3 (WFC3/IR) images of the Hubble Ultra Deep Field (UDF). This 'UDF12' campaign completed in 2012 September doubles the earlier exposures with WFC3/IR in this field and quadruples the exposure in the key F105W filter used to locate such distant galaxies. Combined with additional imaging in the F140W filter, the fidelity of high-redshift candidates is greatly improved. Using spectral energy distribution fitting techniques on objects selected from a deep multi-band near-infrared stack, we find seven promising z > 8.5 candidates. As none of the previously claimed UDF candidates with 8.5 < z < 10 are confirmed by our deeper multi-band imaging, our campaign has transformed the measured abundance of galaxies in this redshift range. Although we recover the candidate UDFj-39546284 (previously proposed at z = 10.3), it is undetected in the newly added F140W image, implying that it lies at z = 11.9 or is an intense emission line galaxy at z {approx_equal} 2.4. Although no physically plausible model can explain the required line intensity given the lack of Ly{alpha} or broadband UV signal, without an infrared spectrum we cannot rule out an exotic interloper. Regardless, our robust z {approx_equal} 8.5-10 sample demonstrates a luminosity density that continues the smooth decline observed over 6 < z < 8. Such continuity has important implications for models of cosmic reionization and future searches for z >10 galaxies with James Webb Space Telescope.

• OSTI ID: 22078329
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 763; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
CAMERAS
ENERGY SPECTRA
GALAXIES
HUBBLE EFFECT
IMAGES
INFRARED SPECTRA
LUMINOSITY
RED SHIFT
STARS
TELESCOPES
ULTRAVIOLET RADIATION