observations revealed thousands of galaxies scattered across what appeared to be a dark patch of sky, giving us a humbling view of the scale of the Universe.
"Hubble fakes us to within a stone's throw of the big bang itself," reveals HUDF project leader Massimo Stiavelli.
The HUDF field contains an estimated 10,000 galaxies.
ALMA has observed the HUDF for a total of around 50 hours up to now.
One team led by Jim Dunlop (University of Edinburgh, United Kingdom) used ALMA to obtain the first deep, homogeneous ALMA image of a region as large as the HUDF. This data allowed them to clearly match up the galaxies that they detected with objects already seen with Hubble and other facilities.
The second team, led by Manuel Aravena of the Ncleo de Astronoma, Universidad Diego Portales, Santiago, Chile, and Fabian Walter of the Max Planck Institute for Astronomy in Heidelberg, Germany, conducted a deeper search across about one sixth of the total HUDF.
So we began an ambitious program at visible and near-infrared wavelengths as a natural successor to HUDF: the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), pronounced "candles." We designed CANDELS primarily to document the first one-third of galaxy evolution.
The telescope devoted 600 hours--fully 10% of its observing time--to CANDELS for three years, surveying an area of sky 60 times larger than the HUDF, albeit to brighter limiting magnitudes (about 27 for CANDELS compared to 30 for the HUDF).
"The lack of information from ultraviolet light made studying galaxies in the HUDF
like trying to understand the history of families without knowing about the grade-school children," said principal investigator Harry Teplitz of Caltech in Pasadena, California.
That source, UDF j-39546284, was first reported at redshift 10.3 in 2009 using HUDF
Haojing Yan (Caltech) and Rogier Windhorst (Arizona State University) note that the number of distant dwarf galaxies increases right down to the HUDF's detection threshold, so these objects must represent the proverbial tip of the iceberg.
Garth Illingworth (University of California, Santa Cruz) and his colleagues scoured the two different versions of the HUDF: the famous one taken mostly in visible light with Hubble's Advanced Camera for Surveys (ACS), and another taken in the infrared with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS).