Free Astronomy Magazine March-April 2018

50 MARCH-APRIL 2018 SPACE CHRONICLES this kind of galaxies. That is crucial for un- derstanding the full picture of the forma- tion and evolution of galaxies and super- massive black holes” . Answering the question “How did galaxies form and evolve during the 13.8-billion- year history of the universe?” has been one top issue in modern astronomy. Stud- ies already revealed that almost all massive galaxies harbor a supermassive black hole at their centers. In recent findings, studies further showed the tight correlation be- tween the mass of black holes and those of their host galaxies. This correlation sug- gests that supermassive black holes and their host galaxies have evolved together and they closely interacted each other as they grew, as known as the co-evolution of galaxies and supermassive black holes. The gas outflow driven by a supermassive black hole at the galactic cen- ter recently has become the focus of attention as it possi- bly is playing a key role in the co-evolution of galaxies and black holes. A widely ac- cepted idea has described this phenomenon as the intense radiation from the galactic SMBHs−host galaxies co-evolution deepened by ALMA by ALMA Observatory U sing the Atacama Large Millimeter/ submillimeter Array (ALMA) to ob- serve an active galaxy with a strong ionized gas outflow from the galactic cen- ter, astronomers have obtained a result making themselves even more puzzled: an unambiguous detection of carbon monox- ide (CO) gas associated with the galactic disk. However, they have also found that the CO gas which settles in the galaxy is not affected by the strong ionized gas out- flow launched from the galactic center. According to a popular scenario explaining the formation and evolution of galaxies and supermassive black holes, radiation from galactic centers, where supermassive black holes are, can significantly influence the molecular gas (such as CO) and the star formation activities of the galaxies. ALMA result shows that the ionized gas outflow driven by the supermassive black hole does not necessarily affect its host galaxy. This result “has made the co-evo- lution of galaxies and supermassive black holes more puzzling,” explains Dr. Yoshiki Toba from the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Tai- wan), and main author of this research. “The next step is looking into more data of A schematic view of the fact that an ionized gas outflow (green) driven by the central supermassive black hole does not affect the star formation of its host galaxy. This sit- uation may occur if the ionized gas is outflowing perpendicularly to the mo- lecular gas. [ALMA (ESO/NAOJ/NRAO)]