Mapping the Universe - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 75

Fig. 2.29 The Hubble Ultra Deep Field ( HUDF ) is featured on the map of the universe

Figure 2.29 shows the Northeast quadrant of the map. The Hubble Ultra Deep
Field (HUDF), located near the upper left corner of the image, reached even deeper
than the 1995 HDF. In other words, the HUDF reveals an even earlier stage of
the universe. It looks back approximately 13 billion years, which is about 400-
800 million years after the Big Bang. Its marker is approaching the 10 Gigaparsecs
(gpc) mark on the distance scale. One gigaParsec (gpc) is 3.0857 10 25 m, or 3.26
billion light-years. The HUDF's record was recently updated by the eXtreme Deep
Field (XDF), released on September 25, 2012. The XDF reveals galaxies formed
only 450 million years after the Big Bang.
In addition to the depiction of astronomical objects such as galaxies and quasars,
the circular map of the universe also presents information about which astronomical
objects have attracted the attention of astronomers in terms of citation bursts.
We will explain the concept of citation burst in detail in later chapters of the
topic. Simply speaking, a citation burst of a scientific publication measures the
acceleration of the citations it has received. A strong citation burst is a sign that
the article has generated a significant level of interest in the scientific community,
in this case, astronomers. Figure 2.30 shows that a citation burst was found with
the object QSO J1030 C 0524 between 2003 and 2004. This object, as it turns out,
was the most distant quasar known when it was discovered. Astronomers measure
the redshift of an object with a metric z, which is the change in the wavelength of
the object divided by the rest wavelength of the light. The quasar was discovered to
have a z of 6.28 at the time, which was very high. The next quasar labeled below the
QSO J1030 C 0524 is QSO J1044-0125, which has a citation burst between 2000
and 2004. It is a high redshift quasar as well (z D 5.73). The third labeled quasar,
QSO J1048 C 4637, also has a high redshift (z D 6.23).