83 supermassive black holes found
Astronomers discover 83 supermassive black holes as big as the Sun in the early universe
Astronomers from Japan, Taiwan, and Princeton University have discovered 83 quasars powered by super-massive black holes in the distant universe.
stronomers have discovered 83 quasars powered by supermassive black holes 13 billion light-years away from the Earth, from a time when the universe was less than 10 percent of its present age.
The finding, published in the Astrophysical Journal, increases the number of black holes known at that epoch (a particular period of time in history or a person’s life) considerably, and reveals, for the first time, how common they are early in the universe’s history.
What are supermassive black holes?
Supermassive black holes, found at the centers of galaxies, can be millions or even billions of times more massive than the Sun.
While they are prevalent today, it is unclear when they first formed, and how many existed in the distant early universe.
A supermassive black hole becomes visible when gas accretes onto it, causing it to shine as a ‘quasar.’
About the study
The finding provides new insight into the effect of black holes on the physical state of gas in the early universe in its first billion years.
Previous studies have been sensitive only to the very rare, most luminous quasars, and thus the most massive black holes.
The new discoveries probe the population of fainter quasars, powered by black holes with masses comparable to most black holes seen in the present-day universe.
- The team used data taken with ‘Hyper Suprime-Cam’ (HSC) instrument, mounted on the Subaru Telescope of the National Astronomical Observatory of Japan, which is located on the summit of Maunakea in Hawaii.
- The HSC team is surveying the sky over the course of 300 nights of telescope time, spread over five years.
- The researchers selected distant quasar candidates from the sensitive HSC survey data.
- They then carried out an intensive observational campaign to obtain spectra of those candidates, using three telescopes: the Subaru Telescope; the Gran Telescopio Canarias on the island of La Palma in the Canaries, Spain; and the Gemini South Telescope in Chile.
Findings of the study
The survey revealed 83 previously unknown very distant quasars.
The sample of quasars in this study are about 13 billion light-years away from the Earth. In other words, we are seeing them as they existed 13 billion years ago.
As the Big Bang took place 13.8 billion years ago, we are effectively looking back in time, seeing these quasars and supermassive black holes as they appeared only about 800 million years after the creation of the universe.
Based on the results achieved so far, the team is looking forward to finding yet more distant black holes and discovering when the first supermassive black hole appeared in the universe.
Detection of black holes
Scientists can’t directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation.
But they can infer the presence of black holes and study them by detecting their effect on other matter nearby. If a black hole passes through a cloud of interstellar matter, for example, it will draw matter inward in a process known as accretion.
A similar process can occur if a normal star passes close to a black hole. In this case, the black hole can tear the star apart as it pulls it toward itself. As the attracted matter accelerates and heats up, it emits x-rays that radiate into space.
Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them – emitting powerful gamma-ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others.