Zhuravleva said, “From what we’ve seen in our data, the rising bubbles drag gas from the cluster center, which explains the filaments of stretched gas in the optical images. These new details resulted in the very first velocity map of the cluster center, showing the speed and turbulence of the hot gas.”īy superimposing this map onto the other images, the researchers were able to link the observed motions to the plasma bubbles. Steve Allen, a co-principal investigator and a professor of physics at Stanford and of particle physics and astrophysics at SLAC, said, “Since the SXS had 30 times better energy resolution than the instruments of previous missions, we were able to resolve details of the X-ray signals that weren’t accessible before. To find out, the researchers pointed one of Hitomi’s instruments – the soft X-ray spectrometer (SXS) – at the center of the Perseus cluster and analyzed its X-ray emissions. However, until now it has been unclear what effect the plasma bubbles have on this intergalactic gas. These snapshots revealed how giant bubbles of ultra-hot, ionized gas, or plasma, rise from the central supermassive black hole as it catapults streams of particles tens of thousands of light-years into space.Īdditional images of visible light from the cluster showed streaks of cold gas that appear to get pulled away from the center of the galaxy. Other space missions before Hitomi, including NASA’s Chandra X-ray Observatory, had taken precise X-ray images of the Perseus cluster. In their study, the Hitomi researchers looked at the Perseus cluster, one of the most massive astronomical objects and the brightest in the X-ray sky. Now we understand this mechanism better and see that there is just the right amount of stirring motion to produce enough heat.” Plasma bubbles stirĪbout 15 percent of the mass of galaxy clusters is gas that is so hot – tens of millions of degrees Fahrenheit – that it shines in bright X-rays.
Norbert Werner, a research associate at KIPAC involved in the data analysis, said, “We already knew that supermassive black holes, which are found at the center of all galaxy clusters and are tens of billions of times more massive than the sun, could play a major role in keeping the gas from cooling by somehow injecting energy into it. Yet there is very little star formation in galaxy clusters, and until now scientists were not sure why. Over time, the gas should cool down and clump together to form stars. Galaxy clusters, which consist of hundreds to thousands of individual galaxies held together by gravity, also contain large amounts of gas. KIPAC is a joint institute of Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory. “Although the Hitomi mission ended tragically after a very short period of time, it’s fair to say that it has opened a new chapter in X-ray astronomy.” “Being able to measure gas motions is a major advance in understanding the dynamic behavior of galaxy clusters and its ties to cosmic evolution,” said study co-author Irina Zhuravleva, a postdoctoral researcher at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC). The data, published today in Natur e, were recorded with the X-ray satellite during its first month in space earlier this year, just before it spun out of control and disintegrated due to a chain of technical malfunctions.
These motions (see video here) could explain why galaxy clusters form far fewer stars than expected – a puzzling property that affects the way cosmic structures evolve. (Image credit: SLAC National Accelerator Laboratory) This image created by physicists at Stanford’s SLAC National Accelerator Laboratory illustrates how supermassive black holes at the center of galaxy clusters could heat intergalactic gas, preventing it from cooling and forming stars.
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