HUDF09

HUDF09 The HUDF09 campaign was a deep-field imaging program undertaken with the Hubble Space Telescope using the Wide Field Camera 3 and the Advanced Camera for Surveys to probe the high-redshift universe. It built on prior efforts such as the Hubble Deep Field, the Hubble Ultra Deep Field, and the Great Observatories Origins Deep Survey to detect galaxies near the epoch of reionization, informing studies tied to the Cosmic Microwave Background results from Wilkinson Microwave Anisotropy Probe and later Planck (spacecraft). The project involved collaborations among teams at the Space Telescope Science Institute, European Space Agency, and universities including California Institute of Technology, University of California, Santa Cruz, and University of Oxford.

Background and goals

HUDF09 aimed to extend the depth and wavelength coverage of existing surveys such as the Hubble Ultra Deep Field and GOODS-South by exploiting the then-new Wide Field Camera 3 to reach fainter sources at redshifts z > 6. Principal investigators and collaborators drawn from institutions like Jet Propulsion Laboratory, University of California, Berkeley, Harvard–Smithsonian Center for Astrophysics, and Max Planck Institute for Astronomy sought to study galaxy formation during the Epoch of Reionization, to constrain star-formation histories referenced against results from Keck Observatory, Very Large Telescope, and Subaru Telescope. Goals included measuring luminosity functions similar to those derived in surveys such as CANDELS, testing models from groups at Institute for Advanced Study and Princeton University, and providing target lists for spectroscopic follow-up with facilities like Atacama Large Millimeter/submillimeter Array and James Webb Space Telescope.

Observations and instrumentation

Observations used multiple filters in the Near Infrared Camera and Multi-Object Spectrometer era lineage but specifically exploited Wide Field Camera 3 infrared channels and the Advanced Camera for Surveys optical channels. The program observed the Chandra Deep Field-South region overlapping the Hubble Ultra Deep Field footprint to leverage existing data from Chandra X-ray Observatory, Spitzer Space Telescope, and Galaxy Evolution Explorer. Scheduling coordinated with HST Servicing Mission 4 constraints and used orbits allocated through proposals reviewed by panels including members from National Science Foundation, Space Telescope Science Institute Time Allocation Committee, and international partners at European Southern Observatory. Instrument calibration referenced detector characterizations from teams at Ball Aerospace and software pipelines developed at Space Telescope Science Institute and STScI collaborators.

Data processing and image release

Raw data reduction followed procedures from the AstroDrizzle pipeline and calibrated exposures were combined to create ultra-deep mosaics. Teams at Space Telescope Science Institute and collaborators at Johns Hopkins University applied cosmic-ray rejection, flat-field corrections, and astrometric alignment using catalogs from Sloan Digital Sky Survey and Two Micron All Sky Survey. Photometric zeropoints were tied to standards maintained by National Institute of Standards and Technology and cross-checked against Hubble Source Catalog. Image releases were accompanied by data products and catalogs prepared for public access, coordinated with archives at Mikulski Archive for Space Telescopes and mirrored by repositories at European Space Agency and university data centers including Harvard University and University of Cambridge.

Scientific results and discoveries

HUDF09 enabled the detection of candidate galaxies at redshifts z ≈ 7–10, complementing spectroscopic confirmations obtained with Keck I, Very Large Telescope, and later ALMA observations. Studies from teams at University of California, Santa Cruz, Yale University, University of Tokyo, and University of Cambridge reported steep faint-end slopes of the ultraviolet luminosity function, in dialogue with theoretical models from groups at Durham University and Institute for Computational Cosmology. Results impacted interpretations of reionization timelines constrained by Planck (spacecraft) optical depth measurements and by analyses from Wilkinson Microwave Anisotropy Probe. Investigations characterized morphologies and sizes using techniques developed at Max Planck Institute for Extraterrestrial Physics and helped identify gravitational lensing candidates for follow-up with Keck Observatory and Gemini Observatory.

Legacy and subsequent programs

HUDF09 products fed into major legacy programs such as CANDELS, Frontier Fields, and planning for James Webb Space Telescope deep fields led by teams at Space Telescope Science Institute, European Space Agency, and Canadian Space Agency. The survey informed instrument strategies for JWST NIRCam and coordination with the Atacama Large Millimeter/submillimeter Array and shaped proposals funded by agencies like National Science Foundation, NASA, and European Research Council. Data remain widely used by researchers at institutions including Stanford University, Carnegie Institution for Science, Flatiron Institute, and Princeton University to train machine-learning models and to compare with simulations from Illustris and EAGLE projects.

Category:Astronomical surveys