%0 Generic %1 Oesch2011 %A Oesch, P. A. %A Bouwens, R. J. %A Illingworth, G. D. %A Labbe, I. %A Trenti, M. %A Gonzalez, V. %A Carollo, C. M. %A Franx, M. %A van Dokkum, P. G. %A Magee, D. %D 2011 %K first galaxies high-z reionization %T Expanded Search for z~10 Galaxies from HUDF09, ERS, and CANDELS Data: Evidence for Accelerated Evolution at z>8? %U http://arxiv.org/abs/1105.2297 %X We present our results on an extended search for z~10 galaxies over ~160 arcmin^2 of WFC3/IR data in the Chandra Deep Field South. These public data sets are from the HUDF09, ERS, and CANDELS surveys, and reach to 5 sigma depths ranging from 26.9 to 29.4 in H_160 AB mag. z>~9.5 galaxy candidates are identified via J_125-H_160>1.2 colors, and non-detections in any band blueward of J_125. Spitzer IRAC photometry is key for separating the genuine high-z candidates from intermediate redshift (z~2-4) galaxies with evolved or heavily dust obscured stellar populations. After removing 15 sources of intermediate brightness (H_160=24-26 mag) with strong IRAC detections, we only find one plausible z~10 galaxy candidate in the whole data set, previously reported in Bouwens et al. (2011). However, the present data set is much larger than before and covers a 3x larger area. This allows us to set much stronger limits on the evolution of the UV luminosity function (LF). If the evolution of the z~4-8 LFs is extrapolated to z~10, six z~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~8. The luminosity density above our survey limit is found to increase by a factor 7-25 in only 170 Myr from z~10 to z~8. This increase is >=2.5x larger than expected from the lower redshift extrapolation of the UV LF. Thus we are likely witnessing the first rapid build-up of galaxies in the heart of cosmic reionization. Future deep HST WFC3/IR data, reaching to well beyond 29 mag, will be essential for a more robust quantification of this accelerated evolution based on the detection of larger samples of z~10 candidates reaching below L*.

@misc{Oesch2011, abstract = { We present our results on an extended search for z~10 galaxies over ~160 arcmin^2 of WFC3/IR data in the Chandra Deep Field South. These public data sets are from the HUDF09, ERS, and CANDELS surveys, and reach to 5 sigma depths ranging from 26.9 to 29.4 in H_160 AB mag. z>~9.5 galaxy candidates are identified via J_125-H_160>1.2 colors, and non-detections in any band blueward of J_125. Spitzer IRAC photometry is key for separating the genuine high-z candidates from intermediate redshift (z~2-4) galaxies with evolved or heavily dust obscured stellar populations. After removing 15 sources of intermediate brightness (H_160=24-26 mag) with strong IRAC detections, we only find one plausible z~10 galaxy candidate in the whole data set, previously reported in Bouwens et al. (2011). However, the present data set is much larger than before and covers a 3x larger area. This allows us to set much stronger limits on the evolution of the UV luminosity function (LF). If the evolution of the z~4-8 LFs is extrapolated to z~10, six z~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~8. The luminosity density above our survey limit is found to increase by a factor 7-25 in only 170 Myr from z~10 to z~8. This increase is >=2.5x larger than expected from the lower redshift extrapolation of the UV LF. Thus we are likely witnessing the first rapid build-up of galaxies in the heart of cosmic reionization. Future deep HST WFC3/IR data, reaching to well beyond 29 mag, will be essential for a more robust quantification of this accelerated evolution based on the detection of larger samples of z~10 candidates reaching below L*. }, added-at = {2011-05-14T22:26:06.000+0200}, author = {Oesch, P. A. and Bouwens, R. J. and Illingworth, G. D. and Labbe, I. and Trenti, M. and Gonzalez, V. and Carollo, C. M. and Franx, M. and van Dokkum, P. G. and Magee, D.}, biburl = {https://www.bibsonomy.org/bibtex/2dfad2fb12c96f5e66f94b32cb4f5c2fa/miki}, description = {[1105.2297] Expanded Search for z~10 Galaxies from HUDF09, ERS, and CANDELS Data: Evidence for Accelerated Evolution at z>8?}, interhash = {30f0ddcb31fe580e8c4fbbfee4f99866}, intrahash = {dfad2fb12c96f5e66f94b32cb4f5c2fa}, keywords = {first galaxies high-z reionization}, note = {cite arxiv:1105.2297 Comment: 13 pages, 12 figures, submitted to ApJ}, timestamp = {2011-05-14T22:26:07.000+0200}, title = {Expanded Search for z~10 Galaxies from HUDF09, ERS, and CANDELS Data: Evidence for Accelerated Evolution at z>8?}, url = {http://arxiv.org/abs/1105.2297}, year = 2011 }