Using the VERA radio telescope network, astronomers have gained new insights into the growth of young supermassive black holes in Narrow Line Seyfert 1 galaxies.

An international group of astronomers has taken a crucial step in understanding the growth of young supermassive black holes. Using the latest technology from VERA, a network of Japanese radio telescopes operated by the National Astronomical Observatory of Japan (NAOJ), they have opened up new insights into the formation of these celestial bodies and their potential evolution into more powerful quasars.

It is now generally accepted that almost every active galaxy contains a supermassive black hole at its core, with a mass exceeding the mass of the Sun by millions to billions. However, the growth history that allowed these black holes to have such a large mass remains an open question.

The international team, led by Mieko Takamura, a graduate student at the University of Tokyo, focused on a specific category of active galaxies known as narrow-gauge Seyfert 1 (NLS1) galaxies. These galaxies are predicted to contain relatively small but rapidly growing massive black holes, providing a potential opportunity to study the early evolution of these cosmic beasts.

To gain a deeper understanding of the immediate environment of these strange black holes, the team observed the cores of six nearby active NLS1 galaxies using VERA, a network of radio telescopes with vision 100,000 times stronger than the human eye. In particular, the team used VERA’s recently developed ultra-wideband recording capabilities, allowing them to detect with unprecedented sensitivity the weakly “polarized” radio waves emitted from the cores of these galaxies.

It is known that some radio waves propagating near supermassive black holes show polarization. As this polarized radiation propagates through the magnetized gas surrounding the black hole, the plane of polarization gradually rotates, causing an effect known as the Faraday spin. The degree of this spin (at a given wavelength) is proportional to the density of the gas in the emitted medium and the intensity of the magnetic field. Polarization and Faraday rotation thus provide valuable information about the central black hole’s immediate surroundings.

In addition to the sharpest look ever at the cores of these galaxies, the new data revealed significantly more Faraday spins compared to measurements obtained for older, more massive, well-developed black holes. This indicates that large amounts of gas are present in the nuclear regions of these galaxies, which contributes to the rapid growth of central black holes.

“Supermassive black holes go through a human-like growth process,” Takamura says. “The black holes we observed have characteristics comparable to foodies, similar to young boys and girls with a strong craving for rice.”

These results were published in: Astrophysical Journal Under the name Takamura et al. “Exploring the heart of active narrow-gauge Seyfert 1 galaxies with VERA broadband polarimetry”. Source