Galactic rods: scientists discovered the source of fuel for the Galaxy's nuclear black hole

Scientists have discovered the nuclear power source of the galaxy's black hole

The linear structure of stars and gas that extends through the inner regions of some Galaxies is called the galactic stripe. It can stretch from one inner spiral arm to another across the entire nuclear region. The scientists believe that some of these stripes, found in spiral Galaxies, including the Milky Way, ferry huge volumes of gas into nuclear regions. It has certain consequences, in the form of bursts of star formation and the rapid growth of a supermassive black hole.

According to the astronomers, one of the results of such processes are quasars. But the feedback of these phenomena contributes to the cessation of energy inflows that stops the growth of the black hole. The scientists do not know how conditional bridges and gas inflows are formed and developed.

They suggest that the merging of Galaxies plays a role in this process, namely the physical properties of their nuclei. They actively accumulate gas. The study of the phenomenon is complicated by the density of dust in the material that is not available for optical instruments, making it difficult for them to observe. Measuring in the infrared and submillimeter wavelengths that allows viewing through dust, is the best way to study events in such a situation. Luminous Galaxy ESO 320-G030 has a gas bar.

It is located at a distance of about one hundred and fifty thousand light years. The scientists have never seen signs of a merger, but the nearly 60,000 light-year bar shows possible high star formation in the nuclear region. The Galaxy has no active evidence of the presence of a nucleus and that may indicate a high degree of its absorption.

It also shows the inflowing gas, and this fact makes it the closest prototype of isolated, rapidly developing galaxies, controlled by their rods. The astronomers make observations with ALMA using Herschel's far infrared spectroscopy method. They believe that a nuclear burst of star formation includes 20 solar-mass stars per year, and the phenomenon is supported by a constant flow of gas with a short period of occurrence, it lasts only 20 million years.

The scientists also found an evidence for the presence of three important structural components: an envelope about 500 light-years in diameter, dense around a nuclear disk about 120 light-years in radius, and a compact 40 light-years in size, characterized by a very high temperature. dust. These three components are responsible for about 70% of the Galaxy's luminosity.

Reference: “A proto-pseudobulge in ESO 320-G030 fed by a massive molecular inflow driven by a nuclear bar” by E. González-Alfonso, M. Pereira-Santaella, J. Fischer, S. García-Burillo, C. Yang, A. Alonso-Herrero, L. Colina, M. L. N. Ashby, H. A. Smith, F. Rico-Villas, J. Martín-Pintado, S. Cazzoli and K. P. Stewart, Accepted 27 October 2020, Astronomy & Astrophysics. DOI: 10.1051/0004-6361/202039047