HST/ACS Ultra Deep Field

The HST/ACS Ultra Deep Field (UDF) is a survey carried out using the Advanced Camera for Surveys (ACS) on HST and taking advantage of 412 orbits of the Director's Discretionary time . The survey is expected to reach up to 1.5 mag deeper than the Hubble Deep Field (HDF) and provide the deepest optical view of the Universe. The data will be made public. Scientific drivers of the UDF include probing the tail of the reionization epoch, constraining the star formation history of the Universe, probing the faint end of the galaxy luminosity function, and tracking the origin, structure, and merger history of galaxies as they evolve onto and off the Hubble sequence.

The final structure of the UDF Survey represents a consensus recommendation of a Scientific Advisory Committee to STScI Director Steven Beckwith, supported by planning documents presented by the Local Working Group. e.g.,
The UDF will consist of a single ultra-deep field (412 orbits in total) within the CDF-S GOODS area, observed with the ACS Wide Field Camera using four filters: F435W (56 orbits), F606W(56 orbits), F775W (150 orbits), and F850LP (150 orbits). The HST/ACS UDF is expected to reach a 10 sigma limiting AB magnitudes (for extended source and a 0.2 sq arcsec or 9x9 pix aperture) which is deeper than the Hubble Deep Field (HDF) by ~1 magnitude in the F435W (B) and F606W (V) filters and ~1.5 magnitude deeper in F775W. For more details see the UDF page

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