09:20:06 Alright, thanks everyone for sticking around our next tutorial is from Mathias was kowroski, non thermal effects in the Ag and feedback loop in the CGM thank you for joining us Mateo.
09:20:23 Thank you.
09:20:25 Thank you for this opportunity to tell you a little bit about how non thermal effects may operate in CGM of massive elliptical galaxies and the clusters.
09:20:36 And so, in a nutshell, I'll talk about basically two things, how things are going up by feedback and how precipitation, at least two accretion, and what role in these processes cosmic rays magnetic fields and turbulence plate.
09:20:52 So, since this is a tutorial let's start with something very basic so here we have a cluster. That is radiating it so it's losing energy and therefore, gases are creating into the center, unless the secretion is then followed by this burping black hole
09:21:10 that is producing these bubbles. And so a number of people looked into this problem. Here is an example of a simulation from RTC at all and there's a long list of papers here and hopefully you will find yours on this list if, if not then I apologize,
09:21:26 the main unifying theme here is that all these simulations are hydrodynamic all, so there are no cosmic rays and no magnetic fields. But if we look at the structures here and change our glasses and look at Radio image and then you will see that there
09:21:42 are cosmic rays here. They are filled with radio emission. And presumably, therefore magnetic fields and cosmic rays and so we see cosmic rays pretty much everywhere in space, going from small things, quote unquote small things like the sun, all the way
09:22:00 to.
09:22:04 To pulsars supernovae Starburst galaxies Ag and that will be talking about an event is sausage cluster and present during collision. So, this whole business started with Victor Haskell discovered cosmic crisis Pang mentioned on bob yesterday and Victor
09:22:26 has live in the Nobel Prize for this, this work. And so, cosmic rays play an important role, and so therefore it's important to ask some very basic questions about the physics of cosmic rays and again since this is a tutorial, some very basic physics
09:22:39 for you. So to first ordinary countries cosmic rays, as a fluid so we have here some moves here on ice moving, getting affected.
09:22:49 Since this is fluids, approximately, we can also talk about pressure forces, and so those will be important. They can move guys around.
09:22:57 And finally, we also have some other mechanism here that, that in addition to a direction that you can see here, cosmic rays can also move around and discuss a little bit so this is this diffusion and, and streaming that we've been talking about and there
09:23:12 there is a little bit of subtlety involved in this last process and I want to go over some topics that Pang also alluded to, a moment ago, or yesterday.
09:23:27 And so this is a customer acquaintances gyrating along magnetic field line that's kind of moving like a bead on the wire because the star ratings is a very small.
09:23:31 On the other hand, if Jerry, this is a very large, much larger than the fluctuations then a cosmic ray just sees the main magnetic field so that's what we naturally expect but an interesting thing happens at this resonance condition where these two length
09:23:43 scale fluctuation link scale and radius links scale are comparable. And this is a complicated blog, but really the essence of it the gist of it it's pretty simple.
09:23:54 We have a magnetic field that looks like this fluctuating wave on a rubber band and gyrating around it is this cosmic ray proton, for example, and at these three locations you can calculate Lawrence force by looking at velocity and shown in this arrow
09:24:11 fields, and the resulting force is acting to the left in this case, and there's always some net force acting on this cosmic great product, and relative directional this for is depends on the face of these toys, but there was always some net force that
09:24:27 doesn't really change the energy of this particle in the frame of this wave, and therefore this wave can scatter these more cosmic Ray Kroc bounce back and forth until they are net drift speed, adjusting to the speed of this fluctuating wave or alpha
09:24:44 And if you try to move these cosmic rays faster in one direction, they will have to lose momentum lose energy positive energy to this wave, wave will grow, and then subsequent dumping of this wave will lead to a gas heating.
09:24:58 And so, not surprisingly, the heating of gas by cosmic rays depends on our faint speed and the pressure gradient and cosmic rays. These are necessary for this to happen.
09:25:09 Also we have this conditional heating where cosmic rays collide with is Mr ICM or a CGM and produce other particles and gamma rays so that's something to keep in mind as well.
09:25:18 Okay, so we can now start constructing these basic models, we can start with some pressure gradient here as a function of radius tangled fields, and the number of people worked on this over the years, and basic thing that I would like to start with is
09:25:32 a simple estimate, we can take this heating rates, due to cosmic rays and compare it to relative cooling. And we can request this in terms of something that is easily understandable so plasma beta parameter which was just the ratio of gas pressure to
09:25:50 magnet to magnetic pressure and that's the number that we know it's about 200 or 30.
09:25:55 So this first number here is small cosmically pressure support is also small compared to gas in at least in large ellipticals, and these subsequent two numbers ratio.
09:26:09 Height of atmosphere to cosmic ray pressure heights, I this thickness here, that can be a large number and so is this precipitation rates too cool to tff and so if you multiply all these numbers together.
09:26:21 The thing that I want you to remember is that this number can be run to unity. So in other words, in this diffuse Halo so you can have heating comparable to cooling.
09:26:31 Now, this works on a piece of paper, but devil is always in the details. So let's look at the devil here. This is what outflow from an AGM looks like this is actually from the Virgo cluster, it looks more like this viscous fluid here doesn't really look
09:27:02 like, let's say flame from a cigarette. So, there's some disgusting on or some gigantic fields as you want just mentioned, viscous these probably suppressed so it's most likely magnetic fields, and you can actually trace their trajectory or shape by looking
09:27:03 at HR filaments superimposed on X ray and mission and you can clearly see that there is a lemon or rather than turbulent flow.
09:27:10 And there is a beautiful result that I recently saw that shows the radio mission from from these objects, and it's clearly indicative of some presence of magnetic fields and cosmic rays, there is a simulation here that shows the draping effects and also
09:27:26 the leaking of cosmic rays from from those slopes. So magnetic fields play a role and cosmically play a role and now we can start asking yourself the question whether these simple estimates can be really realized an actual simulations.
09:27:39 So there's a beautiful work from Crystal Prommers group that looks at this and it attempts to quantify hitting rates from cosmic rays streaming instability, they just mentioned, and tries to compare it to analytic estimates that are guaranteed to have
09:27:56 cooling versus hitting balance that are shown here this is from the UK open Frommer. This is hitting view to cosmic rays This is conduction and and blue line the schooling and so how do these analytic one the models compared to these 3d models.
09:28:11 Well, it turns out that these sophisticated 3d models actually oscillate around what is expected to have a successful heating model, we're cosmic let's play a very important role.
09:28:24 Now, as I said a moment ago, not only do we have this streaming instability hitting we also have hitting associated with collisions. And so, this is to say that the amount of hitting that you will get depends really on what these lobes are made of.
09:28:39 And so this is an interesting result from across the others that shows that far ones that are very common in cool course can be proton dominated as opposed to fr two sources that can be left on dominated or electronic wasn't from dominated so you can
09:28:54 start wondering what sort of consequences. This will have on on the results. And so I want to draw your attention to this very beautiful results from Abdullah and others that looks at sZ effect.
09:29:06 And these two blogs that are seen here indicates that basically these bubbles inflated by the Asian are devoid of hot medium. They have to be filled with with cosmic rays and folks simulated these kind of effects.
09:29:23 This is from Karen young and also from Crystal Palmer's group, and you can see these, the criminals are in increments of the positions of these bubbles, and they can be only present when you fill the structures with cosmic rays, as opposed to the hot
09:29:37 gas if you fill up, fill them up with how the gas and basically there'll be no as the signal, but with cosmic rays there will be a missing gaps quote unquote missing gas.
09:29:47 Now we can dissect it even more and look at basically what's kind of cosmic rays Do you have over there. If you feel the structures with protons.
09:29:55 You will not exceed the gamma ray limits versus if you filled them with electrons limits will be exceeded and so that's another probe of what's going on and what these halos are actually populated with.
09:30:06 Now, we don't really have time to go into this, but this is clearly related to the subject. So we have fairly bubbles that also radiate because they are filled with some high energy particles that interact with seeing the background.
09:30:21 And there's a long standing debate whether this is driven by still or feedback or Ag and feedback. And so I just want to advertise that this new result the beautiful result from Rosita that will be shed new light on this and help us understand what actually
09:30:35 is going on here. And specifically, Mark was broken and cardiac truck Sarkar will be talking about this next week so I just can't wait to learn more about this.
09:30:45 Alright so we talked about one of the models, 3d models, what if you let these jets pump more cosmic rays into these structures so this is the closest cluster and 87, and you can see that as you go from the smallest scale sort of black hole is to progressively
09:31:00 larger is basically shows you that the entire core is filled with with cosmic rays so what's the impact. So, in order to understand what is going on here you have to actually run the simulations for longer.
09:31:13 And basically, in a nutshell, my want to argue here that physics, really matters so if you take just how to dynamical simulations.
09:31:21 They are terrible content will quickly mix with the surroundings, and it will probably work but reality is more complicated you have MHD and hedonic and cooling processes and image, they will try to suppress this mixing and these two other processes that
09:31:36 are heating will not be particularly efficient in transferring energy from the bubbles to the surrounding so we are back to what I was talking about in the beginning, you can have the streaming of particles, out of these bubbles.
09:31:50 And it's streaming not only removes the particles from the bubbles but it also generates this heating that I mentioned in the beginning that we estimated on this.
09:31:58 One of the first slides.
09:32:00 So, what do we got here, if you run this in two different settings one with just hydraulic heating and cooling heating and the second case with streaming you will notice that not only is the source more intimate and the but also the heating, it's spread
09:32:17 and utilize very efficiently.
09:32:20 And this has significant implications for whether you can actually support these atmospheres against catastrophic cooling.
09:32:28 Now we can quantify this a little bit more you can plot pressure support in cosmic rays versus gas so this is what it shows you this is pressure of cosmic rays divided by pressure in in regular gas colors are dimmer when when streaming is present versus
09:32:46 are brighter when streaming is not included so streaming basically reduces pressure support because energy of cosmic races utilize to hit the gas, and that agrees, better with with what's out there in the real world, in particular because streaming does
09:33:04 not really produce a gamma rays it could lead to some violation of therapy constraints.
09:33:07 So this model works reasonably well and so we are moving to larger and larger scales cosmic rays have been also included in cosmological simulations, with AGN only recently.
09:33:18 this is an example from a fire simulation that shows energy density as a function of distance, and this is magnetic contribution. This is cosmic create contribution here and at the top you have thermal contributions so contributions are comfortable here,
09:33:34 and also heating rates are comfortable This is cooling rate. And this is cosmic heating rate. So there's progress and there's indication that the cosmic rays can play a role in this context cosmic rays specifically injected by the AGM.
09:33:50 And so, in the claim has been made in this paper also industry ASCII and others that cosmic rays and order combined with turbulence could suppress going flows in a cosmological session.
09:34:03 Okay, let me switch gears a little bit we talked about how things are getting out, and let's talk about how things are falling down and what role cosmic rays magnetic fields and turbulence can play here.
09:34:14 So, again this hasn't been going on for a while. This is a nerdy simulation from Mike my court and shows that you can have precipitation and and accretion of these blobs when clinging sufficiently fast and again number of people contributed to this result.
09:34:31 and a lot of progress has been made since then. So here are some examples from recent simulations that show the morphology of precipitating gas is quite interesting and I believe we learned a lot from from these results.
09:34:46 So, one thing that I would like to draw your attention to is that there is precipitation going on. This is just access here in this direction and there's lots of precipitation and lots of cold clouds.
09:34:56 They are very clumpy, so that's one thing to keep in mind. Also, an interesting thing to notice here is that are these discs.
09:35:04 And this has seen. This is seen in this simulation q amp a at all also show it's my own group also got the same result.
09:35:13 Invariably, in these simulations we get these discs and, and they are very massive and it's not exactly what we always tend to see in in the real world.
09:35:23 In the real world, we have pretty messy distribution of glimpses you want to show. So these this is kept to somehow disappear. And so I would argue that thermal instability has something, some important interaction with the magnetic field, and this is
09:35:37 an example from the sun. You can see how thermal instability strongly affected by magnetic fields. So we should add magnetic fields to the simulations and again the fear is a simulation that Charlie one performed at shows pressure support do to thermal
09:35:53 components and non thermal component in the magnetic field in the bulk of the CGM in this giant elliptical. What is some in red here is the enhanced magnetic pressure, specifically of the location of the blogs.
09:36:17 magnetically dominated the simulation also includes cosmic rays but we didn't look at support to the cosmic rays. This has been done for example by in a bookstore recently, and who demonstrated that cosmic rays can actually provide significant pressure
09:36:38 to these structures, which takes me to this question of whether you could power these blobs by cosmic rays, and magnetic reconnection for example. So what else can these magnetic fields do here so if you take magnetic field and the rapid around this blog
09:36:45 flying through the CGM and place it in a gravitational field, then magnetic tension will tend to extract angular momentum from this blob. And it will try to reduce its velocity which is important.
09:36:57 From the observational point of view. There's also an interesting analogy to the morphology of this field and run preface tripping and I would like to point your attention to ruler paper.
09:37:09 Krista Frommer's also on this talks about Russia interaction and magnetic fields.
09:37:16 Now, so what what do these magnetic fields do to these blobs as they are folding in in this feedback loop. It turns out that you can extract this energy of these blobs very quickly by magnetic fields, this is energy of of the blobs and this is the rate
09:37:31 of energy extraction, and the only thing that we have to remember here is that extraction timescale is about 10 million years in this particular case, which is interesting because if you look at histograms of velocities of these clouds.
09:37:46 It turns out that instead of having very low expectation which I'm just plotting with the cursor will be around here. You get narrower distribution if you add ramp pressure stripping that also you want a night worked on, but you got even more suppression,
09:38:01 and even narrower distribution of this width of lines, if you include magnetic fields, and I was really impressed with the first keynote on talk by Sherwin Chen, who actually reported on this kind of result in giant quiescence halos were velocities were
09:38:20 actually smaller than expected. And so I would argue that that this may be happening when magnetic fields are included. And our this group here is not the only one that has done it.
09:38:45 There's also interesting result by frickin Vanderbilt, who looked at the impact of magnetic fields with our applicants and so we find essentially the same result.
09:38:37 Now I have one or two minutes I want to mention one more thing. So we talked about cosmic rays magnetic fields and we just heard from you wonder about turbulence.
09:38:51 So turbulence, we like to describe using kilometer of spectrum and to describe this cascade.
09:38:58 We can also describe it in terms of velocity structure function that is more easily observable and colonography prediction, can be translated into this velocity Structural Function that scales like separation between points to power of one third.
09:39:13 And you can see more on this in the ones tutorial and also mark avoids and chart alongside four minute videos.
09:39:21 And so if we include magnetic fields in these calculations of precipitation and try to calculate what the velocity structure function will look like. It turns out that first of all morphology is very different in this case, without magnetic fields the
09:39:35 distribution is very blobby with magnetic fields to the various Elementary.
09:39:39 In both cases, actually, the velocity Structural Function or the velocity separations as a function, religious differences as a function of separation are non Komarov, which is a bizarre results and I would argue that at least as far as cold face is concerned,
09:39:56 one plausible explanation is that this has something to do with reputational emotion so this lots of the second to last blog shows master this flowing in and mustard is blowing out so flowing out mass can be described using of example one least simulations,
09:40:15 On the standards falling down is described for example in predict Sharma simulations. We can look at, specifically the unfolding clouds that are falling down and we can look they dominate and we can look at specific forces acting on these clouds and it
09:40:30 turns out that gravity dominates over magnetic forces, and if you just take two blobs, and you let them fall down and look at how they lost the growth as a function of separation, you will get this scaling.
09:40:43 And that's actually related to what Cameron just asked a moment ago, what will happen to him falling repetitious stripping galaxies, you actually expect the same as scaling last slide.
09:40:54 What about Todd face so hopefully it's going to be stirred by the jet.
09:40:57 This is velocity distribution and can be stirred, especially efficiently. When magnetic fields on presence so you can more get more volume feeling steering.
09:41:07 But we also have called a gas, there's lots of it.
09:41:27 they're going to be non GMO going off.
09:41:30 And I will just leave you with a summary slide rigid main thing I was trying to convey here is that we have these three components non thermal components cosmic rays magnetic fields and turbulence and they are all interconnected and they all play a role
09:41:44 and whenever there is some puzzle very often, that puzzle can be addressed by invoking some of these elements. So, thanks.
09:41:52 Thanks Mateos, there was a whirlwind you covered a lot there that was great.
09:41:59 Are there. are there any questions from, from the audience on these topics. It looks like Frank is first up,
09:42:14 amateurs.
09:42:15 Quick question I mean, the, the interesting result that the common core of our spectrum slope changes. I'm good as be related to the fact that when you have a magnetized medium and you started having all this 40 motions.
09:42:28 You start actually having magnetic reconnection magnetic processes that look at costs energy losses and isn't this just an energy loss process that changes the slope.
09:42:38 That's an interesting question. Let me come back to the silly slide here, because it has the right field morphology, so you have cold blobs and the cold blobs as they fall down, they bring the magnetic fields with them, and the morphology of the field
09:42:55 is as shown here. So, the field goes this way then turns around and in detail. You have magnetic fields in close proximity and they are anti parallel.
09:43:05 And so that's a prime example of where you would actually expect reconnection to take place so that may be happening, although we didn't specifically look at this, there are some, some other papers there's a paper I wrote whether you're in terms of that
09:43:18 looks at actually powering of HR for filaments using this mechanism so this is happening but, as we know, to really model reconnection properly you would need to resort to using some very dedicated experiments that are capable of resolving the structures
09:43:36 extremely Finally, so it's not even I'm not even talking about just a pure linear motion that you're flicking here is also sort of the vortex motion its inherent in the turbulence, that will then cause spin up of magnetic fields and reconnect Yeah.
09:43:51 Yeah.
09:43:52 I mean, eventually this energy has to dissipate summer did this winding up with the field will take place.
09:44:03 Just the FX or energy you don't just just transport all your energy to small school in the meantime you lose some energy.
09:44:10 Yeah, I mean, some small scale to will start this would start monitoring monitoring.
09:44:16 Yeah, I mean that's probably interesting topic to look more into.
09:44:24 Okay, great. it looks like Frank froze as well so I guess we'll cut him off their.
09:44:32 Our next question is from young.
09:44:35 Yes, thank you, a massive amount with your name, motos not cute. Okay, it gets me. Yes, and the beginning of your talk, you showed this work by faith in 2003, where you written a figure has a tough data overlay with expert Yes, exactly.
09:44:57 And that you said here, the, it's more like a lemonade fro a set of turbulence. Could you elaborate more on that, like, what, what is the physics behind it and why you think that's the case.
09:45:08 Yeah, so
09:45:11 there is some indication maybe this is a better picture to look at.
09:45:15 There is some indication that, that these bubbles look more like bubbles in a jar of honey, as opposed to, or bubbles in a, in a glass of water, as opposed to cigarette smoke.
09:45:30 So, these two situations are either viscous, such as in this case, or as effectively viscous and the discussed the stickiness and non ideal hydrodynamic all effects can be caused by by the presence of magnetic fields.
09:45:46 So these will be effectively lower Reynolds number situations and this is where the medium is has relatively little stickiness the width and as more to blend.
09:45:57 So that's not what we really see it's you know how sticky the kind of got maybe it's even better shown here, you can see these strands. This doesn't look like a turbulent flow.
09:46:09 It's quite likely that it is in the wake of these bubbles, where magnetic fields are enhanced, and they provide some pressure support.
09:46:17 So this doesn't really behave like a real like a simple fluid.
09:46:23 I see, so let me rephrase a little bit so if you go back to the hf. Okay. Either way you are showing here is not we are seeing this finger like elongated structures so that's like the bubbles Europe mentioned the 1800s, and that indicates a high regard
09:46:38 number.
09:46:46 You have Okay, yeah, basically the structure here. resemble what's happening in these vortices here they are kind of you could think of them as tracer particles.
09:46:52 They are not going in random directions right they are following this pattern which means are saying that thing that they either its magnetic field or viscosity, but again, as you mentioned, there are constraints on the viscosity so it's probably magnetic
09:47:04 fields that would also explain why these structures are shining in radio I mentioned and and heating the gospel the same time.
09:47:10 Sure. Thank you.
09:47:15 Alright, our next question from Rosie.
09:47:20 I'm a Tish, that was really interesting thank you for that. And so you showed two simulations of an AGM jet, one way you included cosmic rays streaming, and you could see that the heating was much more isotopic.
09:47:36 So I was just wondering how you are injecting the cosmic rays in these yeah that's the one. how you actually injecting the cosmic rays in here and kind of what fraction of the Asian energy.
09:47:50 Are you assuming I just wondered what sort of constraints, there are on how much you would expect. Okay. Yeah. So in these simulations cosmic rays are injected through a jet, that is, I caught in the very beginning in the very center of this domain.
09:48:06 And we assumed that most of the energy in those jets is in the form of cosmic rays.
09:48:13 So specifically, 80% was injected as cosmic rays. So that's actually higher substantially higher than in supernova case where that searching was talking about earlier, but there is a reason for for the assumption that we made here and I'm just going to
09:48:33 go back to this slide for example that shows
09:48:41 that shows what happens when you fill bubbles with cosmic rays right so this is an actual observational result and it's consistent with these structures, being filled with cosmic rays entirely and, and specifically with cosmic ray products.
09:48:57 So that's one example of how one can justify that the assumption that went into these calculations.
09:49:08 Yeah. One thing to keep in mind here is that this situation differs from what you've seen smaller halos so in smaller halos as touching was arguing, you can have almost completely cosmically dominated CGM versus in these more massive halos pressure support
09:49:26 due to cosmic Christ is lower than.
09:49:32 It's definitely sub dominant on so it's kind of a different regime But nevertheless, even though, relatively small amount of cosmic races present, they can actually produce a lot of feeding and maybe I didn't mention this clearly but streaming heating
09:49:46 actually dominates, over, over hedonic loss. So, did I answer your question, or. Yeah, that's great. Thank you. Yeah.
09:49:58 Um, I have a perhaps naive question connecting the youngsters earlier question about the Reynolds number and, and the relevant relative role of viscosity, with the tutorial that you want just gave, and that is, you know, she was mostly dealing with larger,
09:50:13 larger structures like clusters, where she was seeing significant evidence for turbulence and turbulence playing a major role whereas you were showing that in some of these cases at least the AGN.
09:50:26 Cause you know with the presence of magnetic fields, it's much more viscous Lee, you know, a lower Reynolds number, how did those two connected because presumably in these larger structures the clusters, they do have a gn feedback going on in their central
09:50:39 galaxy. So, why do you see these discrepancies in the turbulent.
09:51:03 Well, one way to answer this is that in general, the effects of viscosity.
09:50:57 Kicking on smaller scales, right. So, for example, good way to look at this, is to notice though to remind ourselves that plasma beta parameter is actually very high in these objects.
09:51:06 So this means that gas pressure is much larger than negative pressure. And so gas pretty much pretty much moves the way it wants on large scales.
09:51:17 But when you start looking at tiny things such as for example these clumps that I mentioned at some point here.
09:51:27 When I talked about what what magnetic fields can do on small scales when, when you produce them on instabilities and bring these magnetic fields together, then on those skills.
09:51:39 Actually this is maybe better blot on those small scales where these blobs are plasma beta parameter is not 100 it can be a few magnetic forces on small scales can be important.
09:51:51 So on our skills you could have turbulent motion, such as the one just talked about, but on small scales. You know, it's like kind of I always think about if you take a piece of paper and you start bending on a large scales that's easy right but if you
09:52:07 take a pencil and try to bend it on small scale so you can't really do it. So, so turbulence and our skills and different and discuss effects and small scales.
09:52:16 Excellent. Know that was, that was a great illustration. Thank you.
09:52:22 The next question next hand raised from Daniel way.
09:52:25 Yes, hi, hi Mathias are nice.
09:52:29 I do have a question what was a follow up of will Young's question.
09:52:33 So you may manage your ways smoke from match, but I thought I'd be different scales. Now, you have like a formula bubble whatever kind of for simulation You are the scales of density scales or pressure stairs.
09:52:50 I thought that you see the pop of the X ray is your top kind of more coherent of features. I think that that is a more than a to something like a nuclear bomb, bomb on ground is he's a commercial room, coming up to the top, then, is kind of analogy I,
09:53:14 I, in my mind, so I thought this has probably two ways, kind of content stick and a pressure skier, like also like a song. Since happens, have you comment on Saturday May I seem to be the knowledge or the match smoke from Matt is a much more small scales,
09:53:35 scales, kind of discuss the of course turbulence plays a major role, but PS seems kind of mushroom going up, and may into the atmosphere, then eventually threatens at the top, because the scaling of the, you know, it happens to all the atmosphere of the
09:54:03 Earth, but also happens supposed to be happens in the customers of galaxies, or emergency gym.
09:54:06 I will maybe you could point me to the right, slide that brought that question.
09:54:20 The same slide to us for the like a honey, whatever. Okay, yeah. Okay, back in all.
09:54:36 Yeah, you said five, so this is like more like a mushroom nuclear bomb, and then the smoke from the, from a match, you know you had on the right. Oh, yeah, yeah, yeah.
09:54:38 Okay. And so, so.
09:54:46 Okay. And so, so I'm sorry could could you rephrase this question. But my question is this much more is much more other skier which comparable to the scale of the pressure of atoms.
09:54:58 Yeah.
09:55:00 So you're asking about the, the physical difference between what we see here on the left hand side and on the right hand side, yes.
09:55:08 Okay so, so the difference is caused by the following so you have some gas here that has certain entropy. And that entropy is larger than the entropy of the surrounding gas.
09:55:22 And so, in a nuclear explosion or that you mentioned, or in this case here on the left hand side, this structure will be going up, up until the point where they're dropping inside this bubble will be comparable to the ambience entropy and apparently that's
09:55:40 not the case here.
09:55:43 So, hence the difference.
09:55:44 Yeah, this was started spreading like this laterally when when this march of entropy is actually achieved yes so basically either stability.
09:55:53 With the basically the support you know the assets at the picture in my mind, but the your analogy earlier made is kind of different. I mean to the match the smoke in the match, you know, that I can get confused.
09:56:11 Well, I'm in both cases it's buoyancy that's that's causing this is just that, because of the integrity of this bubble is not preserved due to lack of, you know, strong influence of magnetic fields or viscosity that it falls apart, and then mix us.
09:56:33 Okay, thank you. Thank you.
09:56:37 All right, we'll take one more question and then I guess for consistency, we'll move to a breakout room for any follow up discussions, even though I realized we don't have another presentation to occur.
09:56:48 So Christophe, would you like to ask your question.
09:56:53 Yes, excellent.
09:57:03 So I would like to go back to the Sunni I've said, which effect that you set may be able to constrain a composition. So, um, and I think it's difficult to do this at the low retro universe, because the equivalent magnetic field of the cosmic microwave
09:57:16 background radiation that provides this sort of Converse Converse gathering is the three micro dollars so in other words, if the true magnetic field is largely three micro goals, and it was mostly loose the energy via synchrotron emission that we can
09:57:30 observe the radio. However, if you go to high redshift say Richard foreigner so then the equivalent magnetic group of CDs higher and then provided the magnetic fields within these balances Lord and equivalent magnetic field say whatever 10 Microsoft's,
09:57:45 then the electrons would mostly use the energy wire inverse Congress Kettering potentially be able to be observable. Is this what you were referring to our.
09:57:55 Did I miss something here with discovery limits.
09:58:00 Honestly, the best way to look at this, is to look at Caribbean simulation on this. They don't didn't look, as far as I know they didn't include the effects of redshift on this is the origins of just isolated experiments, as applied to notice more logical.
09:58:22 I think the best thing to do.
09:58:26 The objective of this slide was to emphasize that these things have to be filled with cosmic rays as opposed to the Holocaust right and we can have a debate on whether this is cosmic ray problems or electrons.
09:58:39 And I think the very good venue for this would be the discussion, close to the end of this workshop.
09:58:46 As far as I remember, I think it's maybe seven or eight week where Dyson The Guardian neglect audio will be talking specifically about these issues.
09:58:56 Yeah, I don't think that that actually they make a lot of gamma rays, especially at least that low redshift because elephants primarily cool why single transmission which in fact we already observe and radio and you know you've seen as you've shown this
09:59:11 amazing Meerkat observations where you can, you know, see individual magnetic flux two tubes, being lit up by the cosmic rays electrons there.
09:59:21 I so currently young, obviously, includes magnetic fields in her simulation so they have, they do have the capability to include losses due to synchronization as well.
09:59:34 But we can look at this in detail and see, you know, what are the caveats or or not.
09:59:42 All right.
09:59:43 Okay.
09:59:45 So, thank you for the wonderful presentation, materials, so we have reached the 10 o'clock time for people who need to leave obviously you need to leave.
09:59:54 If there's further discussion, we don't. I mean it's silly to go to a breakout room when everyone's here so if people have additional questions I saw Blakeslee had her hand up a couple of moments ago, if there any other additional questions or Sumo had
10:00:09 a comment in the chat that perhaps is, is worth discussing. I encourage people to raise their hands and we can continue with this for as long as we want.
10:00:20 Basically, but if people need to leave because we're at the end of our time, then people need to leave. So
10:00:28 any questions from the audience or discussion points for Mateo, and his wonderful whirlwind coverage of AGN non thermal processes.
10:00:41 I can ask my question really quickly.
10:00:44 So yeah, I was curious like in terms of like the change in slope of your velocity structure functions. So in the ASM community there's been a lot of work on this.
10:00:56 And basically the slope can be very resolution dependent.
10:01:06 In addition to, you know, all the other things that I've mentioned so I don't know if you have you done like a resolution study Have you checked, like a Helmholtz decomposition to see which modes you might have more of those those would be like the first
10:01:27 things I think I would check if I was after you know exactly the scaling and what's causing it. Yeah. Um, okay, good question. Um, so in terms of the modes.
10:01:30 I did not decompose this into saw an idol and compressible modes, but that's something that can easily be done from previous work on on this.
10:01:40 If I remember correctly, the work that I did with paint on this and I, if I remember correctly the non compressible modes, were more abundance.
10:01:53 But this is something that definitely can be looked at and maybe this will actually shed light on what is actually responsible for this steepening we had this debate, well that may be may be steering by a GM may be steering by the cold blobs may be gravity
10:02:02 waves play around but looking at the compressible versus incompressible mode may be something that would provide further constraints. And as far as other question that you asked about resolution, yes we did look at the resolution, and the solid part of
10:02:24 this result is that resolution does not affect the velocity structural function of the cold face, which is the one of the main result of this paper so the slope is steeper than Komarov in the cold face and then that conclusion did not change with the
10:02:45 resolution.
10:02:46 So that gives us hope.
10:02:54 Any other any other topics for discussion or questions from stage.
10:03:12 I just want to follow up on the last question I thought it was an excellent question. So do you have an idea where your numerical dissipation scale is here in this clock.
10:03:23 Yes, we looked into this by controlled experiments that actually didn't have any complications of the source, such as a gn or thermal instability.
10:03:36 And we just basically took a stratified box, such as, you know, this one but without all these complications. And we started using actually non solenoid Oh, sorry solenoid steering as far as I remember.
10:03:54 So, In this simple experiment, we were able to look at where the power spectrum of the velocity structure function begins to bend over at how smallest is that particular range, and for for this simulation it for the simulation at this resolution here.
10:04:14 That's bending over began at about zero points. A tequila Part Six.
10:04:22 So everything above it above that scale was safe.
10:04:29 Okay.
10:04:32 And where does he recorded. So that is about right here when these lines much or right here where these lines much what basically when you see these bifurcation is where the in the controlled experiment.
10:04:47 The spectrum started bending but but this range here, where the spectrum is clearly steeper than the Nakamura prediction.
10:04:57 The result was unaffected by resolution as a follow up to you.
10:05:04 In this experiment Did you also include, you know like the same refinement criteria you use for for a run and do you have an idea of what the refinement does to this kind of turbulence especially for the cold, medium, yeah this is a very good question.
10:05:17 Unfortunately, that there's no issue with this because we were kind of worried about this for a while so what we did, we took this large box, which was about half an acre parcel sighs.
10:05:29 What you're looking at here by the way this is just the zoom in on the center which is only a few kilometers or 610 or so.
10:05:38 And we fully refined that region to maximum level of refinement, and we didn't touch that refinements at all we just kept it.
10:05:47 Basically, this is a uniformly refined box in the very center and so yeah I was, I was worried about the issue you just raised myself so that's why we did it the way we did.
10:06:07 I'm Brian O'Shea Do you want to use chimed in a bit in the chat relevant to the resolution and the codes that were used to resolve this. do you want to ask those questions directly.
10:06:21 Oh, they weren't questions they were statements. Okay.
10:06:29 Oh, we have a quote max you have another question.
10:06:37 What's that mean it's to my tears, but also to the audience I mean I really like this. The last part exactly on this slide that you You brought, you know, between, between these connections of this Trinity right and I mean as you know and we all know
10:06:50 you know we we can really resolve this small scale magnetic field structure and and not the, you know, not also not the smallest guy turbulence So, so I was wondering how, you know, what do you think is it, you know, I mean are, for instance cost me grace
10:07:08 how much can we trust you know if we don't put these, this, this Moscow turbulence and B fields in, and in kind of a slightly different question related to the small scale turbulence.
10:07:20 Do you know what's the, you know, what's the state of, you know, term small scale turbulence separate models employed in such simulations that that you just showed.
10:07:31 Well the simulations, really done some good prescriptions for for what's happening inside these called columns, the major some good prescription that is in this model that was presented in in the simulations that I showed in the end of this presentation
10:07:50 is the prescription for energy injection by the Ag and and and the heating prescription for cosmic ray heating but there are no prescriptions for what's the velocity field inside the clouds is and how cosmic ray pressure affects the internal structure
10:08:07 of these clouds and that's not really, That's not really something that is
10:08:12 possible to even consider with the simulations at this point I mean you have to do, what, what you max are doing, you have to actually look at individual cloud, and then look at how magnetic fields and the cosmic rays will affect you know the last the
10:08:28 powering and so on. We can just study global properties about, basically the quote unquote turbulence that we're talking about is about emotions of gas and large scales.
10:08:41 Excellent. So perhaps a way of parameter rising the behavior and in some of Max's simulations and feeding that back into the global larger scale.
10:08:52 I wouldn't didn't want to you know self advertise or I wasn't referring to, I kind of saw that I was specifically referring to, you know, some great turbulence mother says employed and you know like global climate simulations or, I believe in supernova
10:09:05 simulations, this kind of thing. So, so, so you know we have a distribution of blobs there's plenty of these blobs they are flying through different environments, some are more democratized environment summary less monetized environment.
10:09:18 Some of the simulations include cosmic rays as well so we have assemble of these of these of these clouds, and you could provide prescription or I could provide a, a list of histories of of these clumps.
10:09:32 And what fields, they go through with magnetic field what what cosmic ray pressures they are encountering and so on and so forth and maybe that could be fed into your, your simulations to learn something about the statistics of these objects and what
10:09:44 happens on on small scales inside these clumps right because you're looking at typically you take just one cloud and you put it in a winter. Now, what if I told you what the typical parameters that these clouds are experiencing in this ICM or CGM could
10:09:58 be maybe you could learn something from that
10:10:03 question from Frank really related to the slope of the coma girl spectrum. Not como spectrum in the turbulence. You know I spent, you know, given the problems and small scale some resolution on large scale at least you know you should measure it reliably
10:10:18 but the assumption is always that we're driving it at one scale and then we should see it human decay but of course it driving itself have an entire power spectrum.
10:10:26 So, so can you rule out that, for example on large scales, you're just driving into the power speculators power half instead of one third and you're fooling yourself thinking that you're seeing some deviation from turbulence, it's just the driving power.
10:10:42 Okay, so let me see if I understand the question so you can obviously large scales are resolved right, or you can clearly.
10:10:48 Look how how gases through life skills, whether it's by a gn or buying falling clumps.
10:10:55 So, on those large scales, you will also see departures from from como golf right i mean what you see you see in the in the HD simulation the hydro simulation, the image he looked actually very nicely coma girl.
10:11:06 but the hydro pure hydro one had a slope of a half. They if when you look at the coalface. They all looked Dunkelberger off.
10:11:18 Yeah, so on life skills they all look Dunkelberger irrespective of whether magnetic field was present or not, and the ultimate reason for this is that.
10:11:30 So, even with my guess. So this is a plot showing force versus time, and there are different contributions to forces acting on in falling clumps.
10:11:40 The dominant forces of gravity. It's essentially independent of time in this particular example, there is magnetic field that is also approximately independent and of time and there are other forces such as Russia stripping forces as well, but the gravity
10:11:55 is dominance. And so, when you look at the clump that is falling from from large distance it's subject essentially to gravitate not exactly ballistic right it's not it's not realistic because there are the special forces from magnetic fields but but it's
10:12:18 Essentially this dependence. So that's why we believe that the clouds that are called are
10:12:29 characterized by this sort of the SF and interesting thing is that these emotions are radio Lee biased. So that's, you know, something what you would expect in the precipitation model, they are not going sideways, they are not tangentially biased.
10:12:42 So,
10:12:47 any other.
10:12:49 Any other questions or discussion points.
10:12:53 I saw a hand. Raise but then it went down.
10:12:57 Well, I might as well just quickly say that.
10:13:07 One point is that we don't capture feline wandering in in low resolution simulations. So, you know that affects to cause me to transport in diffusion is effectively a sort of separate prescription for that so it's just something good to keep in mind.
10:13:27 Okay, well I encourage people. Oh, another question, another point for max. All right, what was then the different a regarding the power loss low, so what was you know the difference then between your simulations and the simulations from the last speaker
10:13:43 where she said she didn't she did see a coma glorified so not in a Not this one half. But, I mean, but if it's this gravity. I mean assume she also included gravity in her situation so what would you have an idea what could be the difference.
10:14:02 I visit physics in hypo simulations is the same. Essentially, I mean, there may be differences in how the jet is modeled.
10:14:11 And actually, you want is also on this call I just scroll down.
10:14:15 I mean in the principle, in principle, there should be no difference.
10:14:20 And by the way just to be very clear about this, these simulations are intentionally presenting, or the way they've been processed is such that we intentionally.
10:14:31 Stay away from projection effects. So what we are saying the simulations is that intrinsically these simulations.
10:14:39 They are turbulence, quote unquote turbulence is non Komarov.
10:14:43 So I actually don't know in you, in one slide whether you whether you want to we're looking at projected vSf or, or not, although you made an interesting argument that with projection, you should get even steeper, the SF.
10:14:58 I mean, in principle, there should be there should be no no difference.
10:15:03 projection makes it shower shower. Oh,
10:15:08 yeah, I'm self you see a super Cabo bar soap in projection, which is what we did and the real observations, then the real slope should only be even steeper.
10:15:21 Right. And so here we are talking about here is this intrinsic three dimensional turbulence and but even that should be called more of like, we know prior to us, starting all this work and thinking on this we expected that turbulence will become aware
10:15:38 of, but even that wasn't done so.
10:15:43 I know projection effects can mess things up.
10:15:49 Um, well i i thank everyone for their for their, their points, the wonderful tutorials from you on Mateos and searching, I encourage people to use the slack channels devoted to turbulence devoted to cosmic rays and devoted to magnetic fields for further
10:16:07 discussion on this topic, because as we've noted slack stays on around indefinitely whereas the zoom windows and chats don't necessarily So, please, please speak up in those venues and continue these discussions and we will catch you guys tomorrow for
10:16:25 Ellen's Bible's keynote at eight o'clock and follow it up with the discussion so thanks everyone. wonderful job.