AstroTalk Episode August 17, 2017

Solar Eclipse, Super Massive Black Holes and Jellyfish (?), and the Rise and Fall of a Fleeing Blue Glow

3:02pm - 3:30pm

Super massive black hole feeding on a cosmic jellyfish. A group of Italian astronomers are using the MUSE (Multi-Unit Spectroscopic Explorer) instrument on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile to view gases being stripped away in galaxies. The galaxies in question have been called "Jellyfish Galaxies", because long arms or tentacles of gas in the galaxies are extending out tens of thousands of light-years from the center of the galactic discs. The process causing the extensions is called "Ram Pressuring". An interstellar wind in the cluster of galaxies is forcing gas out along the arms, because the gas seems to be less bound to the galaxy than it is to the force of the interstellar wind. Along with the ram pressuring, and the outflow of gas, comes the triggering or formation of new stars. 7 galaxies are involved in this study, and to scientist's surprise, 6 / 7 of the super-massive black holes in the center of these galaxies are actively feeding on gas. Normally, less than 1 / 10 super-massive black holes in the centers of galaxies are known to feed on the gas surrounding them. The scientists sum it up by stating that, "This strong link between ram pressure stripping and active black holes was not predicted and has never been reported before,” said team leader Bianca Poggianti from the INAF-Astronomical Observatory of Padova in Italy. “It seems that the central black hole is being fed because some of the gas, rather than being removed, reaches the galaxy center.” So the research is pointing to the fact that, a new mechanism for black feeding (for super-massive black holes) has been discovered. The findings are being hailed as contributing to an understanding on the poorly understood theories or connections between host galaxies and their super-massive black holes. In our next story, astrophysicists from UC Santa Barbara, using the Las Cumbres Observatory (LCO), have observed an exploding star slamming into a nearby companion star. The light from the explosion is coming through in "an unprecedented level of detail". The astros believe that Supernova 2017cbv occurred when a white dwarf was stealing matter from its companion. The companion is thought to be 20 times the radius of our Sun. The blue glow would not have occurred if the companion to the white dwarf were another white dwarf. Because the researchers alerted other telescope stations around the world, they were able to capture the full extent of the rise and fall of the blue glow of such an event, for perhaps the first time.