Perseus A: Mysterious X-ray Signal Intrigues Astronomers
A new study of the Perseus galaxy cluster, shown in this image, using NASA's Chandra X-ray Observatory and 73 other clusters with ESA's XMM-Newton has revealed a mysterious X-ray signal in the data. This signal is represented in the circled data points in the inset, which is a plot of X-ray intensity as a function of X-ray energy. The signal is also seen in over 70 other galaxy clusters using XMM-Newton. This unidentified X-ray emission line - that is, a spike of intensity at a very specific energy, in this case centered on about 3.56 kiloelectron volts (keV) - requires further investigation to confirm both the signal's existence and nature as described in the latest Chandra press release. Read more
Explosive venting from a supermassive black hole are sprouting plumes of material 300,000 light-years across. Observations by the Chandra X-ray Observatory revealed the energetic plumes of particles associated with a massive galaxy cluster called Perseus A. The results provide evidence that a black hole can influence the space around it to intergalactic distances.
Expand (347kb, 720 x 695) Position(2000): RA 03h 19m 47.60s Dec +41° 30' 37.00" Size: 284 arcsec In the galaxy cluster NGC 1275, bubbles appear to be generated by high-speed jets blasting away from the vicinity of the giant galaxy's supermassive black hole. Individual bubbles seen in the inner regions expand and merge to create vast plumes at larger distances. Credit: NASA/CXC/IoA/J.Sanders et al.
Enormous bright loops, ripples, and jet-like streaks are apparent in the image. The dark blue filaments in the centre are likely due to a galaxy that has been torn apart and is falling into NGC 1275, a.k.a. Perseus A, the giant galaxy that lies at the centre of the cluster.
"In relative terms, it is as if a heat source the size of a fingernail affects the behaviour of a region the size of Earth" - Andrew Fabian of Cambridge University.
Fabian is lead author of a report to be published in the Monthly Notices of the Royal Astronomical Society. The Perseus cluster contains thousands of galaxies, all embedded in a giant cloud of superheated gas. The gas alone has the mass of trillions of suns. The plumes, seen clearly in enhanced images from X-ray data, are low pressure regions in the hot gas extending outward from the central galaxy, NGC 1275, which is one of the largest galaxies in the universe. The low pressure is likely the result of the displacement of the gas by bubbles of unseen high-energy particles.
The bubbles appear to be generated by high-speed jets that shoot out from the supermassive black hole residing in NGC 1275. Individual bubbles in the inner regions expand and merge to create vast plumes at larger distances. Earlier this year, observations from the Hubble Space Telescope revealed bubbles blown in a similar fashion by the output of another black hole.
"The plumes show that the black hole has been venting for at least 100 million years, and probably much longer" - Jeremy Sanders, Cambridge University, co-author.
The venting produces sound waves that heat the gas throughout the inner regions of the cluster and prevent the gas from cooling and making stars at a significant rate. This process has slowed the growth of NGC 1275. The hot gas pressure is assumed to be low in the plumes because unseen bubbles of high-energy particles have displaced the gas. The plumes are due to explosive venting from the vicinity of the supermassive black hole. The venting produces sound waves which heat the gas throughout the inner regions of the cluster and prevent the gas from cooling and making stars at a high rate. This process has slowed the growth of one of the largest galaxies in the Universe. It provides a dramatic example of how a relatively tiny, but massive, black hole at the centre of a galaxy can control the heating and cooling behaviour of gas far beyond the confines of the galaxy.
Expand (344kb, 695 x 576) Special processing designed to bring out low and high-pressure regions in the multimillion-degree gas in the Perseus cluster has revealed huge low-pressure regions (shown in purple in the accompanying image overlay). These regions appear as expanding plumes that extend outward 300,000 light years from the supermassive black hole in NGC 1275, the giant central galaxy in the cluster. The gas pressure is assumed to be low in the plumes because unseen bubbles of high-energy particles have pushed the gas aside. The plumes are evidence of explosive activity near the supermassive black hole. Scale: Image is 284 arcsec across (Credit: NASA/CXC/IoA/J.Sanders et al.)
William Herschel discovered the 11.6 magnitude galaxy NGC 1275 on October 17, 1786. In NGC 1275, one galaxy is slicing through another. The disk of a dusty spiral galaxy is cutting through a large elliptical galaxy. Galaxies can change significantly during a collision like this, with gravitational tides distorting each galaxy and gas clouds being compressed and lighting up with new star formation. Galaxy collisions occur in slow motion to the human eye, with a single pass taking as much as 100 million years. NGC 1275 is a member of the Perseus cluster of galaxies that lies about 230 million light years away toward the constellation of Perseus. Each galaxy spans about 50,000 light years across.
NGC 1275 is a strong radio source (3C 84), and shows variability that has occasionally been attributed to seeing a BL Lacertae-like object "off the beam". There is clearly something rich in gas and dust in front of NGC 1275, with the interloper's redshift is 3000 km/s higher than that of NGC 1275 itself.