Quasars are like cosmic lighthouses powered by supermassive black holes that are up to a billion times more massive than the solar system's sun.
Quasars are among the brightest objects in the universe that they eclipse the ancient galaxies that contain them. Situated billions of light-years away, they are also the most distant objects that scientists can currently study.
Astronomers have been fascinated by these powerful dynamos since they were discovered half a century ago.
Quasars, however, are notoriously difficult to identify. Searching for distant quasars is comparable to finding a needle in a haystack but a survey conducted by Carnegie Institution for Science astronomer Eduardo Bañados and colleagues nearly doubles the number of known quasars in the early universe.
The astronomers identified 63 new quasars, the biggest number to date to be reported in one scientific study.
Quasars can help scientists better understand what happened after the Big Bang, the widely accepted theorized event that marked the beginning of the universe. Until now however, the number of identified ancient quasars was so small that scientists have limited opportunities to gather information from them.
The newly discovered quasars though are anticipated to give scientists valuable insights on the first billion years after the Big Bang occurred.
"The number of quasars at z>5.6 presented in this work almost double the quasars previously known at these redshifts, marking a transition phase from studies of individual sources to statistical studies of the high-redshift quasar population, which was impossible with earlier, smaller samples," the researchers wrote.
The most popular theory of the universe's origin posits that the universe was created in the Big Bang. Hot matter was blasted everywhere by the birth of the universe. As time passed, matter cooled off and the first protons and electrons were formed. These later coalesced into hydrogen atoms, which made the universe dark for a long time.
It was only after these atomic nuclei formed larger structures that the universe lighted up once again. The first sources of light that may have included quasars emerged when gravity slowly condensed the hydrogen atoms.
Much about this era when the lights of the universe were turned back on are still shrouded in mystery, but by studying ancient quasars, scientists may be able to decipher what happened in the first billion years after the Big Bang.
Bañados said that very bright quasars offer the best tools for scientists to study the early universe.
The survey that led to the discovery of the 63 new quasars will be reported in the Astrophysical Journal Supplement Series.