CiTR

Italian astronomers using the MUSE (Multi-Unit Spectroscopic Explorer) instrument on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile are studying how gas is being stripped away from some nearby galaxies. The galaxies are nicknamed jellyfish galaxies, because streams of gas resembling tentacles, are being stripped away, and are being fed into their central black holes, causing these galaxies to shine brightly. The tentacles are formed by a process called "Ram Pressure Stripping", where the mutual gravitational attraction of the galaxies (which are falling into a galaxy cluster) create a hot, dense gas. This gas acts as a powerful wind that forces the gas out of the galaxies, and creates the long tentacles, which are tens of thousands of light-years long. It is these tentacles that fuel the super-massive black holes in the centers of the galaxies, and make them shine brightly. Astronomers are surprised at the extent of the feeding of the black holes. 6 of the 7 galaxies in the survey exhibit the phenomenon of Ram Pressure Stripping, far more than expected. The astronomers working on this project claim that the strong link between RPS and the feeding of the black hole with gas was not expected (at least not to this extent). The astronomers are puzzled as to why the gas emissions are reaching the central black holes, instead of being removed from the galaxy. In general, only a very small fraction of super-massive black holes (that inhabit the centers of galaxies) are active, or are devouring matter.
In other astronomy news, A Fleeting Blue Glow is being seen with a star that is "only" 55 million light-years away. An exploding star (or supernova) is seen to be gobbling up a companion star, but, to the surprise of astronomers, the companion is not a white dwarf star. The exploding star emits very bright blue radiation, something that could not have happened if the companion star was another white dwarf. Because of the brightness of the blue emission, astronomers believe that the companion star had to be about 20 times the mass of the white dwarf. In ordinary supernovae of this type (type 1a), the white dwarf that goes supernova usually steals gas from a companion star that is much the same size that it is. Supernova SN 2017cbv is in galaxy NGC 5643, and at 55 million light-years away, is one of the closest supernovae that have recently been discovered. Linking their PROMPT telescope in Chile to a "Panchromatic Robotic Optical Monitoring and Polarimetry" system allowed the astronomers to capture a supernova explosion in a much quicker time than was previously possible. The event was then looked at by 17 other robotic telescopic networks around the world. With this revolution in data acquisition, much was learned about supernovae in this explosion. In particular, the astronomers viewing the SN were seeing how the exploding star could wreak havoc on its companion. Additionally, astronomers were not expecting the companion to be approximately 20 times the mass of the exploding white dwarf star.