HUBBLE SPACE TELESCOPE PRESS RELEASE NO.: STScI-PR04-28 HUBBLE APPROACHES THE FINAL FRONTIER: THE DAWN OF GALAXIES This image is the deepest portrait of the visible universe ever made by humankind. Called the Hubble Ultra Deep Field (HUDF), the million-second long Hubble exposure reveals the some of the earliest galaxies that formed about a billion years after the Big Bang. The hot young stars in these tiny galaxies reheated the Hydrogen in the universe, which had been cold and dark before that time ever since the epoch of Recombination, which ended about 380,000 years after the Big Bang. This Hubble image offers new insights into what types of objects formed and finished reionizing the universe about a billion years after the Big Bang. The image was taken by the Advanced Camera for Surveys (ACS) installed on-board the Hubble Space Telescope by Shuttle astronauts in March 2002. The HUDF picture required a series of exposures taken during 400 Hubble orbits around the Earth. The exposures started Sept. 24, 2003 and ended Jan. 16, 2004. With planned interruptions, the total exposure was 11.3 days of pure viewing time. Both images reveal galaxies that are too faint to be seen by ground-based telescopes, or even in Hubble's previous faraway looks, called the Hubble Deep Fields (HDF's) which were taken in 1995 and 1998. The faintest objects visible in the HUDF are more than 10 billion times dimmer than what the unaided eye can see on a dark night. Hubble's faint object viewing power is therefore equivalent to being able to see a firefly at the distance of the Moon. The image extends one-tenth the diameter of the full Moon, which is akin to looking at a tiny piece of sky through one of the very narrow holes of a stirrer-straw held against your eye. But this very tiny patch of sky contains about 10,000 galaxies, which are all visible here. In ground-based images, which are much shallower than the HUDF, this patch of sky in which the galaxies reside appears largely empty. The distances to these faint galaxies are between one and 12.8 billion light years away from us. One lightyear is the distance light travels in one year, or about six trillion miles --- the number of miles in a light-year is about as large as the number of dollars in the US national debt in 2006. The most distant galaxies seen in the HUDF are about 75 billion-trillion miles away from Earth. Their light has traveled up to 12.8 billion years to reach us --- hence, we see these galaxies as they were 12.8 billion years ago, when the universe was just about one billion years old. The HUDF therefore provides a complete journey back in time till about one billion years after the Big Bang. Due to the expansion of the universe, the most distant objects have most of their light shifted from the ultraviolet/blue to the red/near-infrared part of the spectrum. The most distant and reddest objects about 12.8 light-years are seen when the universe was 7 x smaller than today --- their light has been redshifted by a factor of 6 from the blue to the red. At very these large cosmological distances, the tiny angular diameter of the Hubble Ultra Deep Field spans about 3.6 million light years across. In a volume a few million light-years across one finds today typically only one or two giant galaxies, such as our own Galaxy and its neighbor the Andromeda galaxy plus their satellites. A few stars in our own Galaxy show up as the bright objects with ``spikes'', like drops on the windshield of a car when viewing a distant city at night. All other 9996 objects in the image are distant galaxies. The brightest yellow spiral galaxy in the lower right corner [depending on the orientation of the actual photograph] is about a billion light-years away from Earth, or about 1000x further away than our neighboring galaxy, the Andromeda nebula. At the distance of 12.8 billion light-years, not a single large galaxy is seen in the HUDF. Instead, one sees over 100 faint red clumps spread all across the image, each consisting of at most one billion stars. Over the course of time, each of these clumps will collide many times with its neighbors to grow into progressively larger objects --- until they have reached the mass of about 100 billion stars that we see in giant galaxies today. Hence, the HUDF reveals a good part of the entire history of galaxy formation and evolution, from the first billion years after the Big Bang until 12.8 billion years later today. This process of galaxy assembly can be seen as the many colliding, merging and train-wreck like galaxy encounters in this image. The Hubble Ultra Deep Field field is located in the constellation Fornax, the region is just south of the winter constellation Orion. The HUDF images will help us prepare to design and plan the observations to be done by the sequel to Hubble --- the James Webb Space Telescope (JWST). The JWST is a fully deployable 6.5 meter infrared telescope to be launched by NASA and ESA in 2021 into a stable orbit around the Sun, about 1.5 million kilometers away from Earth --- about 5x further away from Earth than the Moon. Being about one million miles from Earth, the JWST will orbit in a much darker sky-background than Hubble, and be able to explore the entire epoch of ``First Light'' about 200--400 million years after the Big Bang, when the very first stars started shining, which ended the Dark Ages and started the epoch of Reionization, of which Hubble has now seen the very tail end. For further details, please contact: Dr. Rogier A. Windhorst Regents' and Foundation Professor JWST Interdisciplinary Scientist School of Earth & Space Exploration Street: 450 E. Tyler Mall, Room PSF-686 Office: 550 E. Tyler Mall, Room GWC-508 Arizona State University P.O. Box 871404 Tempe, AZ 85287-1404, USA Tel: +1-480-965-7143 or 9416 or 8950 or 5081 FAX: +1-480-965-6362 Email: Rogier.Windhorst@asu.edu or Rogier.Windhorst@gmail.com http://sese.asu.edu or http://www.jwst.nasa.gov https://webbtelescope.org/contents/news-releases/2018/news-2018-23/ https://asunow.asu.edu/20180425-discoveries-see-first-born-stars-universe or Dr. Ray Villard Space Telescope Science Institute 3700 San Martin Drive Baltimore, MD (Phone: 410-338-4514; E-mail: villard@stsci.edu) =============================================================================== The first 2004 release of the Hubble UltraDeep Field images is on: PRESS KIT: https://hubblesite.org/contents/news-releases/2004/news-2004-07.html FULL RES: imgsrc.hubblesite.org/hu/db/2004/07/images/a/formats/full_jpg.jpg (Beware: The latter image is 60 Mb in size at full resolution). The 2004 press release of the Hubble UltraDeep Field and Cosmic Dawn is on: PRESS KIT: https://hubblesite.org/contents/news-releases/2004/news-2004-28.html FULL RES: imgsrc.hubblesite.org/hu/db/2004/28/images/a/formats/print.jpg The 2014 press release of the 13-filter Panchromatic Hubble UltraDeep Field on: PRESS KIT: https://hubblesite.org/contents/news-releases/2014/news-2014-27.html FULL RES files: https://www.asu.edu/clas/hst/www/aas2014/ Best UV-rendered file: HUDF14-pan-IRrendered.tif Best IR-rendered file: HUDF14-pan-UVrendered.jpg =============================================================================== The HUDF AHaH Java Tool developed for HST and JWST is available at: http://ahah.asu.edu/ http://ahah.asu.edu/index.html http://ahah.asu.edu/download.html Documentation of the AHaH code is available on: http://ahah.asu.edu/help.html Related classroom exercises available for public outreach are available at: http://ahah.asu.edu/exercises.html or: http://windhorst114.asu.edu/ or: http://windhorst114.asu.edu/ahah/index.html The HUDF clickable map, that is relevant for JWST, is available at: http://ahah.asu.edu/clickonHUDF/index.html =============================================================================== All JWST work at ASU can be found at: http://www.asu.edu/clas/hst/www/jwst/ Past JWST studies done at ASU can be found at: http://www.asu.edu/clas/hst/www/jwst/jwststudies/ JWST related talks given by Rogier Windhorst can be found at: http://www.asu.edu/clas/hst/www/jwst/jwsttalks/ and: http://www.asu.edu/clas/hst/www/jwst/othertalks/ JWST related papers by Rogier Windhorst et al. can be found at: http://www.asu.edu/clas/hst/www/jwst/papers/ ===============================================================================