Tokyo: Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found regions where certain organic molecules somehow endure the intense radiation near the supermassive black hole at the center of spiral galaxy M77, also known as NGC 1068.
Although these molecules around a black hole are thought to be dissociated by strong X-rays and UV photons, the research results indicated that some regions are shielded from X-rays and UV photons due to a large amount of dust and gas.
A research team led by Shuro Takano at the National Astronomical Observatory of Japan (NAOJ) and Taku Nakajima at Nagoya University observed the spiral galaxy M77 in the direction of the constellation Cetus (the Whale) about 47 million light-years away with ALMA.
These results, which were made possible by the high sensitivity and wideband observing capability of ALMA, will be a key to understanding the mysterious environment around supermassive black holes.
ALMA observations revealed clearly the distributions of nine types of molecules in the CND and in the starburst ring. The observational results show that the molecular distribution varies according to the type of molecule. While carbon monoxide (CO) was distributed mainly in the starburst ring, five types of molecules, including complex organic molecules such as cyanoacetylene (HC3N) and acetonitrile (CH3CN), are concentrated in the CND.
In addition, carbon monosulfide (CS) and methanol (CH3OH) are distributed both in the starburst ring and the CND. ALMA provided the first high resolution observation of the five types of molecules in M77, and revealed that they are concentrated in the CND.
The research team assumes that organic molecules remain intact in the CND due to a large amount of gas which was shielded from X-rays and UV photons, while organic molecules cannot survive the exposure to the strong UV photons in the starburst region where the gas density was lower compared with the CND.