Hubblecast 62: A spiral galaxy with a secret

The NASA/ESA Hubble Space Telescope with a little help from an amateur astronomer has produced one of the best views yet of nearby galaxy Messier 106 a striking spiral galaxy with a number of secrets Hubblecast episode 62: A spiral galaxy with a secret Located a little over 20 million light-years away practically a neighbour by cosmic standards Messier 106 is one of the brightest and nearest spiral galaxies to our Milky Way Although it may not look particularly unique some of its features have baffled astronomers for years Messier 106 has a supermassive black hole at its centre Although this is true for most galaxies this black hole is particularly active and hungry gobbling up nearby material at a startling rate This huge black hole’s bottomless appetite is behind much of the galaxy’s unusual behaviour Messier 106 appears to be emitting powerful radiation from its centre something we do not see with our Milky Way This is caused by the very active black hole at the galaxy’s centre which violently drags gas and dust inwards This material heats up, emitting microwave and X-ray radiation as it does so However, this emission is not the most intriguing feature of this spiral galaxy This image shows the galaxy’s other not-so-hidden secret: alongside its two regular star-packed spiral arms it appears to have two more, made out of hot, glowing gas While these ghostly extra arms have been known about for decades astronomers were unsure of how they formed — until recently Yet again, the culprit is Messier 106’s supermassive black hole The extra arms are actually regions of gas that have been heated up to scorching temperatures of millions of degrees As material spins around and heats up at the galaxy’s centre the turbulent motion causes jets of material to shoot outwards The jets disrupt and heat up all the gas in their path which in turn excites denser gas towards the centre of the galaxy This gas is tightly bound together, so it remains roughly straight However, the looser gas further out is blown away from the jets so that it curves out of the galactic plane creating the arching red arms seen in this image These “extra” arms are very unusual, and this poses a bit of a puzzle because galactic jets are actually quite common It is not just spirals that show jets elliptical galaxies do too, such as the spectacular radio jets seen around the nearby galaxies Hercules A and Centaurus A And yet none of these show any of the features seen in Messier 106 Some of the data for this image of Messier 106 were provided by amateur astronomer Robert Gendler Together with Hubble, these data allow us to visualise the galaxy’s chaotic centre and mysterious structure better than ever before Hubblecast is produced by ESA/Hubble at the European Southern Observatory in Germany The Hubble mision is a project of international cooperation between NASA and the European Space Agency www.spacetelescope.org Transcribed by ESA/Hubble. Translation ––