Powerful outflows observed from early quasars

Artist's concept of a quasar (Image ESO/M. Kornmesser)
Artist’s concept of a quasar (Image ESO/M. Kornmesser)

An article published in the journal “Astronomy & Astrophysics” reports an analysis of 48 quasars in the early universe to detect the outflows of materials they produce. A team of researchers led by Manuela Bischetti of the Italian National Institute of Astrophysics in Rome used the ALMA radio telescope to confirm for the first time the common existence of those outflows, which act as powerful winds inside those early galaxies heavily interfering in the formation of new stars.

Thanks to particularly powerful and sensitive instruments, in recent years it’s been possible to investigate the early universe discovering among other things very ancient supermassive black holes. Astronomers are still looking for evidence of the possible mechanisms that allowed so soon in the history of the universe the formation of objects with masses of many millions if not billions of times the Sun’s.

What’s certain is that those supermassive black holes could be very active thanks to the presence around them of considerable amounts of materials that got heated to the point of emitting even very energetic electromagnetic waves. The result is a quasar, one of the brightest objects in the universe. Another branch of research concerns the influence of those black holes on the galaxies that host them.

The ALMA radio telescope, inaugurated in March 2013, has the power and sensitivity to detect certain emissions from ancient quasars. Focusing specifically on the distribution of ionized carbon, the team led by Manuela Bischetti used ALMA to examine 48 quasars that we see from Earth as they were about 13 billion years ago. The result was the detection of outflows, winds with velocities above 1000 km/s which are emitted in opposite directions from an area close to the disks of materials surrounding the supermassive black holes.

Compared to research conducted in the past, this one was focused on quasars with outflows of considerable intensity. A single early quasar with those characteristics had already been observed because the observations weren’t deep enough to detect the outflows. In this case the researchers conducted the observations precisely to look for them.

The result is important because it shows how those outflows act as powerful winds that prevent star formation by wiping out the gas, which cannot coalesce. This is a step forward in understanding the relationship between supermassive black holes and the galaxies that host them. For this reason, the researchers will continue their early quasar observations and their studies will intertwine with those of other astronomers.

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