New research has revealed how supermassive black holes, which lurk in the hearts of large galaxies, affect the distribution of chemicals throughout their galactic home.
Scientists understood this a long time ago supermassive black holes have a huge influence on galaxies around them. In particular, when these black holes feed on the matter surrounding them, they form electromagnetic emitting radiation that is bright enough to outshine the combined light of every star in their home galaxy. This active delivery process also causes jets of matter to shoot outward from a nearby black hole the speed of light.
Together, these phenomena treat the galactic heart as an active galactic nucleus (AGN) and heat gas and dust, as well as push star-forming matter away from the region, which can limit star birth and thus stunt the growth of the galaxy itself. However, scientists do not understand so clearly how the distribution of chemicals in galaxies is affected by AGNs and their supermassive Black hole engines.
The new research was conducted by a team of astronomers who used Atacama Large Millimeter/submillimeter Array (ALMA) to look at the supermassive AGN galaxy NGC 1068, also known as Messier 77 (M77) or simply the “Octopus Galaxy”. In particular, the researchers were interested in analyzing the distribution of chemicals around the clear heart of this barrier spiral galaxylocated 51.4 light years away from Earthin the constellation Cetus. The Black hole associated with this AGN is enveloped by a thick ring of dust called the circumnuclear disk and surrounded by a region of intense star formation, the so-called starburst ring.
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“Recently, an important and interesting problem about galaxies has been the investigation of energy sources in active galaxies, focusing in particular on obscured galactic nuclei, which are the central engines of galaxy starbursts, or AGNs,” the team behind the research writes in the paper. paper published in Astrophysical Journal. “Observations revealing energy sources can provide key information regarding the evolution of galaxies. A chemical approach that involves the use of line surveys in galaxies is a powerful way to address this problem.”
Thanks to ALMA’s impressive spatial resolution and the use of a new machine learning technique, the team was able to map the distribution of 23 molecules present in the galaxy.
This is possible because chemical elements and compounds absorb light at characteristic wavelengths, so by looking at light shining through gas and dust, scientists can see “lines” or gaps where the light has been absorbed. This shows the chemical composition of dust and gas.
Specifically, the team observed that hydrogen cyanide isotopes were restricted to the central region of the AGN, while cyanide radicals were also found in the active center of the galaxy, but also shot outwards, in jets emanating from both poles of the supermassive black hole.
The researchers also noticed that unlike these two molecules, isotopes of carbon monoxide – common in galaxies – avoid the central region.
For the team, this is clear evidence that supermassive black holes affect not only the large-scale structure of galaxies, but also their chemical composition. The research brought a few surprises for the researchers as well, as the team found it to be highly energetic radiographs from AGN had less impact on the chemical distribution than theoretically predicted.
“The abundance of cyanide in the circular nuclear disk is significantly lower than the expected value of model calculations in the highly irradiated region,” the authors concluded. “The expected strong X-ray emission from AGNs has a relatively lower impact on the molecular abundance in the circumnuclear disk than mechanical feedback.”
The article about this research was published September 14 in The Astrophysical Journal
