WFC3/IR fields (orange) around the GOODS South area used in this analysis (see Section 2 and Table 1). The HUDF/HUDF09-1/HUDF09-2 fields comprise the deepest NIR data available to date, reaching to 29 AB mag. These three WFC3/IR pointings are covered in a total of 192 HST orbits, which obtained photometry in Y ₁₀₅, J ₁₂₅, and H ₁₆₀. The ERS field consists of 60 orbits of WFC3/IR imaging in Y ₀₉₈, J ₁₂₅, and H ₁₆₀ spread over a 2 × 5 tile. The CANDELS program is an on-going multi-cycle treasury survey consisting of two parts: CANDELS-Deep (~60 arcmin ², limited at H _{160, AB} ~ 27.5) and CANDELS-Wide (~40 arcmin ², limited at H _{160, AB} ~ 26.9). Only J ₁₂₅ and H ₁₆₀ data obtained before 2011 August 6 are used in this analysis (together with the shallow Y ₁₀₅ imaging of CANDELS-Wide).