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all right so this is messier 108 which is actually in the plough constellation or the big dipper if you're in the u.s so if you're in the northern hemisphere and you have dark skies you should be able to see this year round so you know crack out the telescope and see if you can spot it you know what more excuse do you need this is messier 108 as seen last night from my back garden oh you're telling me that's not a hubble image no did you have to go outside in the cold or briefly but then i left the telescope to it and sat in the warm watching telly and checking on my phone to make sure it was doing what it was supposed to be doing it actually goes almost directly overhead in my back garden which is just
as well this time of year because the trees have been growing kind of over so actually the strip of sky i can look at is getting smaller and smaller but happily messier 108 is one of the things that lies in there it's often called the surfboard galaxy because we're seeing it edge on right we're not seeing it face on so we can see all that spiral structure we're seeing it is it's tilted to us around about 75 degrees so it's got that very classic surfboard shape i feel like the surfboard galaxy we should make some sort of beach boys reference like i don't know like if everybody had a tear let's go across the usa they'd be observing the surfboard like charles messier it fits so well i can't for the life of me see why
anyone would think this was a bar galaxy but uh that's what it's classified at it becomes a little clearer i've also have an infrared image of it for you so this is from the two micron all sky survey it's maybe a little clearer here you can see there really is kind of a disk in the middle here and perhaps you can convince yourself that there's a bar in the center and there are spiral arms coming off it i'm not entirely again not entirely clear it's clearly quite a messy looking galaxy it's a lot easier to see actually in this hubble space telescope image of the galaxy and it might also give you some idea of the scale and the fact that it just doesn't fit on the hubble ccd and you can really see those dark dustbands then
essentially what they do is block visible light essentially hiding what's behind that in the galaxy from that region so it makes knowing a lot about m108 quite difficult because of this dust you have to do a lot of corrections for how you think the light has been absorbed and re-radiated and all of that kind of stuff we have a paper here which is called chandra observation so chandra is an x-ray satellite chandra observations of the edgeon galaxy ngc 3556 which they conveniently tell you is also messier 108 violent galactic disc halo interaction revealed violent yes so here's what the charmed review of this galaxy so the line here is kind of the optical where the optical galaxy is so what
we're looking at before is just giving the outline of the galaxy and then the contours are where they've been detecting x-rays and so you can see there are a bunch of little dots here which are kind of point sources of which the most interesting ones are probably this guy here which is the one that's closest to the center and they think that's probably the supermassive black hole that really is at the center the reason it's not exactly coincident with the center is probably because this galaxy is sort of so messy that it's actually hard to define exactly where the center is and actually there is this sort of diffuse stuff that seems to be associated with it and they suggest that
this is actually the violent processes going on around the supermassive black hole are actually throwing material out which is interacting violently with the stuff around to create this kind of cone of emission but then you've got this source here 26. it was the brightest source that they found the brightest but not necessarily the highest energy so suggesting there's obviously something going on there but not necessarily from the biggest of black holes so one of the reasons that i think messi a108 is dead interesting is because i am a researcher that does research on supermassive black holes um is that it contains a candidate for what's known as an intermediate mass black hole which is sort of like the missing link in black hole studies so an
intermediate mass black hole is a black hole that has a mass of anywhere from hundreds to hundreds of thousands of times the mass of the sun and they sit between the stellar mass black holes and the supermassive black holes so if this is massive black hole down here and this is like you know frequency or the number of it we've got the stellar mass black holes you know down here i don't think that's what the distribution looks like but you get the idea and then we've got the you know the distribution of supermassive black holes up here it's sort of like uh a million so 10 to the six and like 10 to the nine and everything like that whereas down here you've got you know tens and now you've got hundreds right so these are the
intermediate ones in here intermediate mass black holes imbh as we call them and what we found is we found things at the tail end of both of these distributions right so for example we found dwarf galaxies that have supermassive black holes that look like they're just under a million times the mass of the sun but we've also found things here as well where we've had two black holes that have merged together for example but we've also found things like down at the top end of the cell mass black hole distribution as well so for example the gravitational wave signal gw190521 which was detected by the ligo observatory right that detects all these gravitational waves and that was thought to be a merger of two black holes 85 and 65
times the mass the sun so they were probably created in supernova but when they merged together some of the energy was radiated away as gravitational waves and they left behind a black hole that was 142 times the mass of the sun technically an intermediate mass black hole right but it's it's on the fringes really what you'd want to do is find something that's like right back smang in the middle backswing smack bang in the middle of those two distributions that's around about you know like a thousand times the mass of the sun or tens of thousands of times the mass of the sun so that's what we think might be in messier 108 a candidate intermediate mass black hole that falls smack bang in
the middle of that sort of empty bit of parameter space where we don't have any of these intermediate mass black holes and from the luminosity you can get at the mass of the black hole that might be giving off it's a little bit woolly and they didn't do it in the paper either this was me sort of being like oh look this correlation that we've seen between x-ray brightness and black hole mass right you can kind of sort of extrapolate the correlation down and find that it's roughly between a thousand to ten thousand times the mass of the sun black hole that could be giving off this x-ray which would put it in the middle here right in between stellar mass and supermassive black holes so it's really cool that we have that candidate in
messier 108 but we still don't know what the mass actually is yet and even if it was an intermediate mass black hole we still don't know how it would grow that big either whether it would be through mergers of black holes whether it would be through this accretion process where they take in mata to find that out we're gonna have to find more intermediate mass black holes here instead of seeing the point sources i mean you can still see a few of the point sources but mostly what you see is this kind of diffuse x-ray emission this is hot gas and this is the violent process that was being referred to in the title of that paper because this is gas that's kind of associated with the galaxy and what we think is happening here is you've got a
disk of stars in some places within the galaxy you have kind of burst of star formation going on shortly after at least in sort of stellar terms the most massive stars will blow up the supernovae and inject large amounts of energy typically that energy will kind of get shot out of the plane of the galaxy and that will heat the gas that's sort of lurking around the galaxy and it's thought that what you're seeing here is that kind of gas which is being heated you can even see and the claim is that some of these features that kind of stick up like that one there or that one down there aren't just sort of spurious noise features they're real things where you've kind of got a fountain of
material that's been shot out here have a load of stars forming some of them blow up the supernovae that kind of blows gas out into the halo of the galaxy creates these very hot plumes of gas and that's what you're seeing there that's kind of violent feedback process from what's going on in the disk of the galaxy it's a relatively nearby galaxy so actually it's easier to spot this phenomenon you know these x-rays are quite faint so actually the phenomenon could well be going on in other galaxies and it's just harder to see because they're further away but it's also clearly a galaxy that there are lots of kind of messy processes going on because it's a very untidy looking galaxy and wherever you have kind of those sort of turbulent
processes you tend to get quite a lot of star formation happening so it's probably forming stars quite rapidly too nice cool so there is got more we're done no all right that's it messier 108. the whole messier catalogue finished hello everyone the publication of this video actually means we've now covered all 110 objects in the messier catalogue if you'd like to go back and watch the videos we've got a special playlist of them all in order there'll be links on the screen and in the video description please do stay subscribed to the channel we've got more plans more videos coming watch this space get it watch this space yeah
