Cosmic Alchemy – New Findings Demonstrate That Supermassive Black Holes Alter Galactic Chemistry

Recent research has demonstrated that the supermassive black holeA black hole is a place in space where the gravitational field is so strong that not even light can escape it. Astronomers classify black holes into three categories by size: miniature, stellar, and supermassive black holes. Miniature black holes could have a mass smaller than our Sun and supermassive black holes could have a mass equivalent to billions of our Sun.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>black hole at the center of a galaxy can significantly influence the chemical composition of the host galaxy. This finding adds a crucial element to our understanding of galactic evolution.

Challenges in Studying Black Hole Influence

It is well known that active supermassive black holes can produce major changes in their host galaxies by heating up and removing the interstellar gas in the galaxy. But the compact sizes of black holes, the long distances from Earth, and the obscuration by dust in the galaxies have made it difficult to measure the chemical composition distribution of the gas around an active supermassive black hole.

Hydrogen cyanide isotopes (H13CN), shown in yellow, are found only around the black hole at the center. Cyanide radicals (CN), shown in red, appear not only in the center and a large-scale ring-shaped gas structure, but also along the bipolar jets extending from the center towards the northeast (upper left) and southwest (lower right). Carbon monoxide isotopes (13CO), shown in blue, avoid the central region. Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, T. Nakajima et al.

Breakthrough Observations with ALMA

In this study, an international team of researchers led by Toshiki Saito at the National Astronomical Observatory of Japan and Taku Nakajima at Nagoya UniversityNagoya University, sometimes abbreviated as NU, is a Japanese national research university located in Chikusa-ku, Nagoya. It was the seventh Imperial University in Japan, one of the first five Designated National University and selected as a Top Type university of Top Global University Project by the Japanese government. It is one of the highest ranked higher education institutions in Japan.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Nagoya University used ALMAThe Atacama Large Millimeter/submillimeter Array (ALMA) is the largest ground-based facility for observations in the millimeter/submillimeter regime in the world. ALMA comprises 66 high-precision dish antennas of measuring either 12 meters across or 7 meters across and spread over distances of up to 16 kilometers. It is an international partnership between Europe, the United States, Japan, and the Republic of Chile.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>ALMA (Atacama Large Millimeter/submillimeter Array) to observe the central region of Messier 77 located 51.4 million light-years away in the direction of the constellation Cetus. Messier 77 is a relatively nearby example of a galaxy hosting an active supermassive black hole.

Thanks to ALMA’s high spatial resolution and a new machine-learning analysis technique, the team was able to map the distribution of 23 molecules. This is the first survey to objectively depict the distribution of all detected molecules through unbiased observations. The results show that along the path of the bipolar jets emanating near the black hole, molecules commonly found in galaxies such as carbon monoxide (CO) seem to break down, while the concentrations of distinctive molecules such as an isomer of HCN and the cyanide radical (CN) increase.

This is direct evidence that supermassive black holes affect not only the large-scale structure but also the chemical composition of their host galaxies.

Reference: “Molecular Abundance of the Circumnuclear Region Surrounding an Active Galactic Nucleus in NGC 1068 Based on an Imaging Line Survey in the 3 mm Band with ALMA” by Taku Nakajima, Shuro Takano, Tomoka Tosaki, Akio Taniguchi, Nanase Harada, Toshiki Saito, Masatoshi Imanishi, Yuri Nishimura, Takuma Izumi, Yoichi Tamura, Kotaro Kohno and Eric Herbst, 14 September 2023, The Astrophysical JournalThe Astrophysical Journal (ApJ) is a peer-reviewed scientific journal that focuses on the publication of original research on all aspects of astronomy and astrophysics. It is one of the most prestigious journals in the field, and is published by the American Astronomical Society (AAS). The journal publishes articles on a wide range of topics, including the structure, dynamics, and evolution of the universe; the properties of stars, planets, and galaxies; and the nature of dark matter, dark energy, and the early universe.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Astrophysical Journal.
DOI: 10.3847/1538-4357/ace4c7