For more than six weeks, the watchful eye of NASA’s Chandra X-ray Observatory kept track of a small portion of sky dubbed the Chandra Deep Field South (CDFS). Its object was to research 200 distant galaxies dating back to about 800 million to 950 million years old. What Chandra was looking for was evidence of massive black holes. The deepest evidence yet…
When combined with very deep optical and infrared images from NASA’s Hubble Space Telescope, the new Chandra data leads astronomers to speculate that young black holes may have evolved in unison with their young galaxies. “Until now, we had no idea what the black holes in these early galaxies were doing, or if they even existed,” said Ezequiel Treister of the University of Hawaii, lead author of the study appearing in the June 16 issue of the journal Nature. “Now we know they are there, and they are growing like gangbusters.”
What does this new information mean? The massive growth of the black holes in the CDFS are just shy of being a quasar – the super-luminous by-product of material slipping over the event horizon. “However, the sources in the CDFS are about a hundred times fainter and the black holes are about a thousand times less massive than the ones in quasars.” How often did it occur in the new data? Try between 30 and 100% of the case studies, resulting in a estimated 30 million supermassive black holes in the early Universe.
“It appears we’ve found a whole new population of baby black holes,” said co-author Kevin Schawinski of Yale University. “We think these babies will grow by a factor of about a hundred or a thousand, eventually becoming like the giant black holes we see today almost 13 billion years later.”
While the existence of these early black holes had been predicted, no observation had been made until now. Due to their natural “cloaking devices” of gas and dust, optical observation had been prohibited, but x-ray signatures don’t lie. The concept of tandem black hole / galaxy growth has been studied closer to home, but taking a look further back into time and space has revealed growth a hundred times more than estimated. These new Chandra results are teaching us that this connection begins at the beginning.
“Most astronomers think in the present-day universe, black holes and galaxies are somehow symbiotic in how they grow,” said Priya Natarajan, a co-author from Yale University. “We have shown that this codependent relationship has existed from very early times.”
Theories also abound which imply neophyte black holes may have played “an important role in clearing away the cosmic “fog” of neutral, or uncharged, hydrogen that pervaded the early universe when temperatures cooled down after the Big Bang”. But to the contrary, the new Chandra findings point towards the pervasive materials stopping ultraviolet radiation before the re-ionization process can occur. Resultant stars and dormant black holes are the most likely culprit to have cleared space for the cosmic dawn.
Although the Chandra X-ray Observatory is up to the task of picking up on uber-faint objects at incredible distances, these baby black holes are so veiled that only a few photons can slip through, making individual detection impossible. To gather this new data, the team employed Chandra’s directional abilities and tallied the hits near the positions of distant galaxies and found a statistically significant signal.
Original Story Source: Chandra News.