An article published in the journal “Publications of the Astronomical Society of Australia” describes the discovery of the fastest growing supermassive black hole. A team of astronomers from the Australian National University (ANU) used data collected by ESA’s Gaia space probe, NASA’s WISE space telescope and the SkyMapper telescope at the ANU Siding Spring Observatory to find it. It’s a quasar, one of the brightest objects in the universe but is more than 12 billion light years away from Earth. It swallows the equivalent of the Sun’s mass every two days.
Cataloged with the initials QSO SMSS J215728.21-360215.1, or more simply J2157-3602, it’s a quasar, meaning an extremely bright galactic nucleus due to a supermassive black hole surrounded by a ring of materials that fall towards it generating very high amounts of electromagnetic radiation. However, even quasars are difficult to detect when they’re billions of light years away, as in this case.
To understand the characteristics of this quasar, the astronomers needed to put together the information gathered with different instruments. Christian Wolf of the ANU, lead author of the research, explained that his team has been looking for supermassive black holes like the one using the SkyMapper telescope for months. J2157-3602 was discovered thanks to near-infrared emissions due to the fact that they shifted towards red due to the considerable distance, which is directly proportional to the red shift.
The Gaia mission’s Data Release 2 was published recently and was helpful to study this quasar because it seemed to be sitting still, a confirmation of its considerable distance. Data collected by the WISE space telescope confirmed its position. The brightness suggested that it was a very massive quasar and new confirmations came from further spectrographic observations made with a Siding Spring Observatory’s instrument.
The growth of this supermassive black hole is a mystery because its mass is estimated at 20 billion solar masses and, because of its enormous distance, we see it as it was over 12 billion years ago, when the universe was very young in astronomical terms. J2157-3602 isn’t the first such ancient quasar observed but it’s an extreme case for the supermassive black hole’s mass.
Christian Wolf explained that if that quasar were at the center of the Milky Way it would appear ten times brighter than the full moon. However, in that case the Earth would probably be sterilized by its X-ray emissions even thousands of light years away.
J2157-3602 is extremely far away but its brightness could help see some details of the objects in front of it. The instruments that will enter service in the coming years could exploit quasars such as this one also to obtain better measurements of the expansion of the universe.