According to a new study conducted by the “Cosmic Web” research group at the University of Milano-Bicocca and NASA, using the US space agency’s Chandra X-ray Observatory, in the early universe a jet of particles originating from a black hole in one galaxy appears to be interfering with a cloud of gas surrounding another nearby galaxy, striking it and slowing down its process of forming new stars.
To illustrate this discovery, the researchers used a culinary metaphor: the black hole appears to be stirring a “pot” of gas containing a “Red Potato”, namely the other galaxy. The galaxy that is slowly being “cooked” is called MQN01 J004131.9-493704, but astronomers nicknamed it “Red Potato” because of its appearance in images from NASA’s James Webb Space Telescope.
The “Red Potato” galaxy is located approximately 11.7 billion light-years from Earth and lies within the same cosmic structure in which researchers from the Cosmic Web group discovered the giant disc galaxy “Big Wheel”, at an intersection where enormous web-like structures of galaxies and gas meet. Astronomers chose to point the James Webb Space Telescope at this area because they knew that it contains one of the highest concentrations of galaxies and growing supermassive black holes ever identified in the early universe.
Since data from the European Southern Observatory’s Very Large Telescope (ESO) show that the “Red Potato” galaxy is surrounded by an enormous cloud, or “pot”, of relatively cool gas, astronomers expected it to contain a large number of young stars formed after some of the gas had been drawn into the galaxy. This phenomenon had already been observed in nearby galaxies surrounded by cool gas. Surprisingly, however, this was not the case for this galaxy.
«Stars are not forming as expected, so we tried to understand why,» says Weichen Wang, a researcher in Astronomy and Astrophysics at the University of Milano-Bicocca, «and we discovered that there may be a “cook” in this “cosmic kitchen”.» An important clue is that the gas cloud surrounding the “Red Potato” galaxy is unusually turbulent compared with the large gas clouds surrounding other galaxies. This turbulence could prevent most of the gas from falling onto MQN01 J004131.9-493704 and forming a large number of new stars.
Wang and his colleagues, working as part of an international team of researchers, therefore searched for the origin of this turbulence. Using Chandra, they discovered that a jet of particles originating from a black hole in a nearby galaxy is directed towards the gas cloud surrounding the galaxy under study and may be striking it, potentially causing the turbulence.
«If the black hole jet is stirring the gas around the “Red Potato” galaxy, it could significantly slow the rate at which the galaxy can acquire new material to form stars,» said co-author and research group coordinator Sebastiano Cantalupo, Professor of Astronomy, Cosmology and Space Science at the University of Milano-Bicocca, who leads the “Cosmic Web” research group. «With the energy generated by this stirring, the galaxy will no longer receive the fuel needed to form new stars at the rate expected for similar galaxies during the same cosmic epoch.»
While the “Red Potato” galaxy is composed mainly of older, cooler stars and therefore appears red in optical and infrared data, the galaxy hosting the black hole with the jet is not. On the contrary, this galaxy, located approximately 200,000 light-years from MQN01 J004131.9-493704, is undergoing intense star formation, with massive, hot stars being formed, as is the case for most of the other nearby galaxies.
Astronomers now want to understand how galaxies and black holes interact with one another — particularly during this critical period in the history of the universe — and how this affects the timing and processes of star formation.
The authors considered other possible explanations for the turbulence in the gas, including outbursts from a supermassive black hole at the centre of the “Red Potato” galaxy or the energy produced by intense new-star formation. However, they consider these explanations less likely than the jet originating from the nearby galaxy.
This work is one of the few published studies to have investigated the behaviour of gas surrounding passive galaxies in the early universe. Data from NASA’s Hubble Space Telescope were also used to support the measurements required to reveal the galaxy’s red colour and its low star-formation rate.
Part of this text is based on the press release published by NASA and the Smithsonian Astrophysical Observatory:
Chandra Sees Black Hole Stirring “Pot” Containing Galactic Potato
Photo credits: X-ray: NASA/CXC/University of Milano-Bicocca/W. Wang et al.; infrared: NASA/ESA/CSA/STScI; radio: ESO/NRAO/NAOJ/ALMA; image processing: NASA/CXC/SAO/N. Wolk and P. Edmonds