Scientists analysed the image statistically and found that the HDF had seen back to the very young Universe where the bulk of the galaxies had not, as yet, had time to form stars. The results were astonishing! Almost 3000 galaxies were seen in the image. The observed region of sky in Ursa Major was carefully selected to be as empty as possible so that Hubble would look far beyond the stars of our own Milky Way and out past nearby galaxies. The resulting image consisted of 342 separate exposures, with a total exposure time of more than 100 hours, compared with typical Hubble exposures of a few hours. The first Deep Field, the Hubble Deep Field North (HDF-N), was observed over 10 consecutive days during Christmas 1995. These images showed many galaxies, which were often quite unlike those we see in the local Universe and could not otherwise be studied using conventional ground-based telescopes. The idea for the Hubble Deep Fields originated in results from the first deep images taken after the repair in 1993. The different deep fields are also a good gathering grounds to find the most distant objects ever observed. Using the different Hubble Deep fields astronomers were able to study young galaxies in the early Universe and the most distant primeval galaxies. In the case of the Hubble Deep and Ultra Deep Fields, it is the extreme distances involved which make them faint, and hence make observations challenging. Astronomical objects can either look faint because their natural brightness is low, or because of their distance. longer exposure time), the fainter are the objects that become visible on the images. Because of the time it has taken their light to reach us, we see some of these galaxies as they were just half a billion years after the Big Bang.ĭeep field observations are long-lasting observations of a particular region of the sky intended to reveal faint objects by collecting the light from them for an appropriately long time. Subsequent deep imagery from Hubble, including the Hubble Ultra Deep Field, has revealed the most distant galaxies ever observed. The first deep fields – Hubble Deep Field North and South – gave astronomers a peephole to the ancient Universe for the first time, and caused a real revolution in modern astronomy. The Deep Fields gave astronomers the first really clear look back to the time when galaxies were forming. Images of faint galaxies give 'fossil' clues as to how the Universe looked in the remote past and how it may have evolved with time. These images of the Medusa allowed us to show that the same relation holds, even in the midst of galactic collisions.One of the main scientific justifications for building Hubble was to measure the size and age of the Universe and test theories about its origin. The blue dots are black hole binaries.Įarlier work had suggested that the number of X-ray binaries is simply proportional to the rate at which the host galaxy forms stars. The blue in the image shows X-rays, imaged with the Chandra X-ray Observatory. The striking appearance of the Medusa arises because it’s a collision between two galaxies – the “hair” is remnants of one galaxy torn apart by the gravity of the other. I obtained this Hubble image (in red) of the Medusa galaxy to better understand the relation between black hole X-ray binaries and star formation.
Some of those stars end their “normal” lives by collapsing into black holes, but then begin new lives as powerful X-ray emitters powered by gas sucked off a companion star. Optical: NASA/ESA/STScI/Univ of Iowa/P.Kaaret et al., CC BY-NC X-ray: NASA/CXC/Univ of Iowa/P.Kaaret et al.
0 kommentar(er)
