09:10:15 Okay, Welcome back everyone.
09:10:17 Yeah, hang that was a wonderful presentation. Thank you very much, very enlightening on a variety of different exciting. I think I had too much coffee, but
09:10:30 ok so the next, the better part of the next hour, we are going to have a panel that addresses various different ideas and, and, and statements that were brought up in the, in the chat as well as the, as well as the presentation by paying the panel consists
09:10:50 of Pang, as well as Evans canopy Aiko who's a professor at Arizona State, as well as has been on loan to NASA for the last couple of years, arena but ski, who is finishing her PhD at University of Washington Blakeslee Burkhardt, who is a new professor
09:11:09 at Rutgers and CCA and Chad bustard, who is, as was mentioned, is a KITP Fellow at UCSB. So welcome panelists. And let's see, so lots of good questions being raised keep them up, and I will try to get them and ask our panel.
09:11:33 One thing that that has been talked to a lot of talked a lot about in the in the chat is.
09:11:40 These clouds and the mist that you're talking about, and the fact that it's so stochastic and the behavior.
09:11:48 What, you know, how many the observers have sightlines traditionally just have sidelines probing individual structures that are for effective purposes just one dimensional one dimensional structures.
09:12:03 How many sightlines or how many galaxies. Do you really need in order to account for this stochastic behavior in the, in the turbulence and, as was pointed out by some of the observers, you know, some of these sightlines have 1015 components along that
09:12:20 line of sight is that enough to be to be sampling this the stochastic behavior and an ensemble of the fog that you were describing.
09:12:29 So I would say that the short answer to that is, we don't know.
09:12:35 We have to figure it out, but I think you know the specific stochastics vi was talking about was was with regard to survival. So, and it's also a function of size.
09:12:49 If you are large enough, then you know you will survive, you know, you will break out into small pieces but you will survive. If you're close to the boundary then survival is a question, but once you are, you know, you're good to survive actually the
09:13:05 growth is a does follow, you know, typical scaling relations and it's you know it's it's not that noisy. Now in terms of the distribution of, as I argued most of the time when you're piercing sightlines you probably see fog, or at least you know clumps
09:13:22 of fog and in terms of, you know, the distribution of those, you know, what you see when you actually look through an entire Halo, that, that also depends on the properties of turbulence in the Halo, I think.
09:13:38 And so what is enough.
09:13:41 Yeah, it's, it's, it's cosmic variance right I would guess that it depends on the current scale of of turbulence, right, you need to capture.
09:13:50 You know, you know quite a few Eddie's at least we don't really know what that steering scale is.
09:13:56 Yeah, so you can see hand-waving don't know.
09:14:01 Okay. Do any of the other panelists have any insight onto this turbulent behavior, they'd like to chime in.
09:14:11 And, and Max to since you you actually want to, you know, please say something if I, if I screwed up. Yeah, absolutely. max you're welcome to chime in.
09:14:22 I don't know if I have any insight, but uh, I'm trying to.
09:14:28 So some of these like fog simulations and things. Um, what do they assume about conduction so this is always the thing that I, I wonder I think a lot of them would change in the presence of, you know, some degree of electron thermal conduction or, or
09:14:47 what results are robust to that, like, how does that fold into the picture.
09:14:53 I don't know if that's to paying or to.
09:14:56 Yeah, I mean anyone else, many of you guys have have incorporated some of these plasma physics effects into your simulations and calculations, so I think I'd love to hear from, from everybody.
09:15:08 What role does this conduction play on this and and.
09:15:13 Is it going to modify this, the behavior of this fog in any capacity or change this, the small, small scale of the clouds. What do you guys think
09:15:29 I'll jump in a little bit. So, conduction introduces and field length which would increase the smallest size, these clouds and like we found in our recent paper.
09:15:42 Non thermal pressure like magnetic fields and cosmic rays also increases that smallest characteristic scale of cool gas clouds that's set by the sound speed and the cooling time.
09:15:54 So in cases where the non thermal pressure dominates you really might have very large, small cool gas clouds.
09:16:02 And I can also add that at least the CST cooling scale, right, um, that that might talk about that is a much smaller than the classical feel length, and in fact that the fuel length doesn't even apply it's actually smaller than the mean free path and
09:16:18 electron in the hot gas.
09:16:23 And, you know, it took it. I think it ends up being very complicated.
09:16:27 I asked, both Chris Mickey and Joe Squires about this and Jonah had some interesting thoughts but we never followed it up, but you know naively right.
09:16:38 This shouldn't happen.
09:16:40 But on the other hand, there's also very little evidence for classical thermal conduction, I think, you know, really, you know, this is sort of my hobby horse like.
09:16:52 We see it in the solar wind, but it's hard to see it. other places I don't think there's anyone that is and where we have evidence for it. So, all the calculations we have done have ignored conduction and yes it would change things enormously.
09:17:04 Yeah.
09:17:07 Could you really have, like, cosmic rays, like free streaming around, but like thermal electrons not.
09:17:15 Maybe that's a question to Ellen or plasma physicists in the audience is there like ways that the relativistic particles can be streaming around but then
09:17:31 the, so that's that's my question.
09:17:36 So that's that's my question. We're getting a lot of cosmic rays to stream why not the thermal collected why not thermal electrons.
09:17:43 Ellen, would you like to, to chime in on this.
09:17:49 Yeah, I yeah I just wanted to say that.
09:17:51 So there are missing not a definitive answer but there are a couple ways that electrons and cosmic rays are different. So, one. Keep, keep in mind that when we talk about cosmic ray streaming, we're talking about the average velocity of a whole ensemble
09:18:08 of cosmic rays, and every cosmic ray particle is moving, you know, a close to the speed of light, and moving their, their directions are almost random deviation from random is only afforded the alphabet speed over the speed of light.
09:18:23 So the other thing to keep in mind is that, um, the, the gyro radius of a cosmic ray is much bigger than the entire radius of an electron, both because of the mass and because it's moving at the speed of light.
09:18:41 So, it.
09:18:42 You know it does. This and other things kind of make me wonder if there could, you know what the low energy cosmic rays are doing to the thermal balance to the ionization and heating we know that they're important in the disk of the galaxy.
09:18:57 And I don't think we know very much about how the gv cosmic rays and the sub relativistic cosmic rays are related.
09:19:04 And so, you know, maybe that's something where chemical modeling could could actually shed some light on what the low energy population is doing. Does that make sense.
09:19:18 So they both may have a different origin, as well as having, like unrelated behavior within the within the Halo and influence on the, on the CGM, will I you know I just don't.
09:19:32 For example, in you know in Starburst galaxies where you know the you know the cosmic energy density could be hundreds of times larger than it is in the Milky Way.
09:19:40 Should you also scale up the you know the ionization rate by two to 10 MTV protons by the same factor probably not probably the losses are very large, but that's just one example of of why it's important question.
09:19:59 Any other points to add on to this for our panel.
09:20:07 Okay, um, Christoph you've had your hand raised for a bit. Would you like to ask a question or make a comment. Thank you so I can check, I want to first comment on the question electron transport for this cosmic ray transport and pink beautifully explained
09:20:31 the fact that cosmic rays self confined by a scattering of open ways.
09:20:30 And can you still see, okay, and the same happens when the cosmic rays electrons, because the electrons are off of whistling waves provided of course, that we have a sufficiently conditional as medium but that happens in this solar wind.
09:20:44 So in fact something very, very simple, similar could actually happening. And, in fact, the resulting MHD equations, look very much alike, the effective cosmic regulations that pen has talked about.
09:21:00 All right.
09:21:02 And my question to bang. So, what about the Fermi tool. If this is dead, effective, I would expect galaxy clusters, to sort of shine very brightly. However, we have the upper limits on the cosmic rate to seven pressure ratio of the order of a percent
09:21:21 for the bulk of the clusters. How can you sort of combine this in your simulation that into the chest the chat.
09:21:27 Yeah. So, great question. You know we have to put numbers to it, but I think at least for the gamma ray constraints, you know, you know, as you know, the, you know, in clusters.
09:21:41 When you talk about those very high energy protons like you know hundred gv or so. 10 to 100 GVU, you're probably in this resonance scattering regime, where for me to is, is really is not a you know what we did with these fluid fluid simulations but you
09:22:02 know you have transit time damping.
09:22:05 And, you know, that's the stuff that you know Brunetti has has done and so forth and so that acceleration efficiency is is quite different there. So what I talked about was, you know, non resident scattering where the mean free path is much smaller than
09:22:23 the scale of the turbulence, and what transit time damping is is when the mean free path is comparable or larger than the, the size scale to Eddie so the physics is quite different there.
09:22:39 But we don't see gamma rays also 100 me which groups gv cosmic race.
09:22:41 So, you know what, so the other possible thing is also you know that there is this sweet spot right for acceleration, right where you compare the diffusion coefficient, to the turbulent diffuse activity, right.
09:22:57 So, the numbers seem reasonable for for our galaxy, where you know the, you know we we have observational constraints on what the effective diffusion coefficient is.
09:23:10 I don't think we have equivalent constraints in a galaxy. But, um, you know the long answer is that, you know, whatever, you know, we have to look at the numbers in detail, but yeah this is an important constraint, but I think the physics is different.
09:23:25 So then if time allows later on I would love to know more about the staircase thing so but you know I don't want to sort of take the sort of. No wait, it's really, it's really quite cool like it, we did understand for a long time but yeah I think this
09:23:41 is like a nerd thing Yeah.
09:23:45 Maybe something for follow up zoom cosmic ray discussion that whoever is interested could join right and sorry I should have, you know, Chad. Chad has some thoughts on on on what you were saying, I think.
09:23:58 Yeah, well I think you covered, you covered most of what I was going to say but I was just going to add in that you know what those simulations had is just constant diffusion so there's no cosmic rays sync terms anywhere, but and you know reality if you
09:24:11 have streaming cosmic rays you have this VA grad p cosmic ray term that paying talked about so this this collision was energy last term.
09:24:21 And that's you know it's unclear in what environments that collision was energy loss might actually offset the, the energy gain from second order for me.
09:24:30 So that's just one other caveat to keep in mind.
09:24:37 So, the that might then explain the lack of like huge gamma ray fluxes in these more massive systems.
09:24:46 So what you're saying.
09:24:47 Yeah, yeah, so you have no that would decrease the growth time of cosmic ray energy you know it might even reverse it so that there's some slow depletion of cosmic ray energy, over time, you know, these are things that we're hoping to look at as we you
09:25:02 know run more and more simulations with different cosmic rate transport models, not just ones that are, you know, including constant diffusion coefficient but ones that are derived from quasi linear theory something like you know a streaming self confinement
09:25:17 model with this extra energy last term.
09:25:22 Okay.
09:25:25 I think the next person who had their hand up was Ryan Farber.
09:25:30 All right, thanks so I have a related question to what's been discussed.
09:25:36 So is this really for me to acceleration is there actually a source term in the models or is this really just a diabetic eating which I thought hinted at in one slide and related to that in terms of the gamma rays if it's really just sort of concentrating
09:25:55 cosmic rays because that also explain why you don't have the issue of clusters being too bright. Is that then it depends on what your injection term is or what the background cosmic ray density is so if you don't have supernova going off, then you don't
09:26:11 end up. If you don't have a very big see then you don't end up concentrating cosmic rays.
09:26:22 Chad you want to do you want to answer otherwise I'm happy to go for it you answer.
09:26:29 Okay so, um, So the first question was, was, you know, yeah I think it's essentially at bat at Keating you know that the reason for that sweet spot is basically, you know, you heat when you compress right and if you, if you diffuse too quickly, right
09:26:49 then you're not going to compress enough.
09:26:51 And then if you refuse to slowly, then that that compression is going to be reversed right you you compress and then you refract and then there's no net energy change.
09:27:03 But, um, you know.
09:27:05 So, but essentially for me to in the end right because it's acceleration of cosmic rays by by thermal motion of bye bye bye motions. And then the second question.
09:27:17 So when we, you know, chat simulation are not terribly sensitive to the seed
09:27:25 cosmic energy because you know you grow very quickly, so you know what he sees is similar to a total turbulent Dynamo for magnetic field so we know that that has to be cosmic rays there because just from structure formation right that's very strong shocks.
09:27:40 You know like Christoph has done a lot of work on this so yeah i don't i don't think that will get us out of that but you know i think you know we just have to look at and honestly this, we're still in the early days, but we were so excited that I wanted
09:27:55 to talk about it but, um, but yeah we will look at the numbers for cosmic rays. So clusters, if there's actually conversion is what you're saying is happening says the thermal pressure dropping as the cosmic ray pressures increasing know the the free
09:28:10 energy comes from the kinetic energy. Yeah.
09:28:15 And those simulations actually assume and Isla thermal equation of state, just to give a little bit more detail. So yeah, the energy come from the kinetic energy.
09:28:27 Okay, so, I know we have a couple of hands up and I will, I will get to them. But I wanted to kind of address a higher level question that encompasses a lot of the themes that that Pang brings up in his presentation, and that is, so you know, we're hearing
09:28:44 about turbulence we're hearing about cosmic rays we're hearing about MHD effects. And it seems like all of these can be sources of super thermal broadening for the observations, but really bringing this back to the observers, like how, what are key constraints
09:29:01 that we can apply from the observations as to what are the dominant modes of these different physical processes like.
09:29:09 Obviously, the MHD and the cosmic rays may have some sort of software p or anisotropy present in them relative to the, to the bulk behavior of the gas but it, it just seems challenging, and I was wondering if the panelists could chime in here.
09:29:26 Are there clear cut indications from the, from both the analytic and the computational theory on ways in which observers can put constraints on these
09:29:41 crickets.
09:29:44 The panel to observers are well, ultimately it's to the panel to give the observers a clue as to where they can like how they can distinguish these different effects observers are free to chime in as well.
09:30:04 I see Todd has unmuted Todd trip is unmuted so perhaps yes on this, you know, a point that I have been making for years, is that there's this uncanny alignment of rather disparate ionization stages, you know, magnesium, two is aligned with oxygen six
09:30:20 or even neon eight.
09:30:22 So that's bizarre to me as a naive observer, and sort of cheap way of explaining that has always seemed to be well there's some sort of magnetic field confinement that that causes these things to be all martial together, even though, you know there's
09:30:40 a range of physical conditions within the cloud, whatever that is. So I put up a question on the slack page and this is actually question for you. Cameron.
09:30:52 Are we at the stage where we can run Trident through some of these things with magnetic field confinement, to see what the kinematics and the range of ionization stages would look like, you know, if that's an important effect.
09:31:11 So that so that's really kind of focused on the magnetic field part but who knows you know maybe the other things play a role as well. Thanks.
09:31:20 Yeah, I think that's a that's a great question. Yeah, to my knowledge, no one has yet done this using Trident or other synthetic spectral generation tools.
09:31:31 But, if someone has done this I'm, I'm happy to be wrong.
09:31:36 And I think, I think it is possible to do this, we just have to trust the, the underlying simulation and how how the, the behavior of the magnetic fields and that sort of thing but it should come out in whatever synthetic spectrum are produced.
09:31:51 I'll jump in to answer that, just a little bit so Jess and I have been working on using Trident to generate synthetic spectra from galaxies run with and without cosmic rays.
09:32:04 And I will say like we do see the alignment of low intermediate and high mass ions in both simulations.
09:32:11 And we do see the super thermal line with in the cosmic ray simulation.
09:32:16 But, I don't know if, like, you know we can't resolve the midst, that paying and.
09:32:33 And Max and Mike, were like writing about so I'm not sure if we're at the point where we can constrain or like make kind of controllable predictions from the simulations, but we do reproduce some of these observed properties.
09:32:43 Thanks to Rena anyone else here.
09:32:50 I can't make some comments I think that, of course, it's better public experts in the audience like Rafi Yoakam, so we can do the radio observations of nearby age young galaxies.
09:33:06 So one method the to constrain the turbulence. And as and as organized the manufactured is through the comparison of the car radiation in the radio faster insensitive to the total magnitude, compared to the polarization measurement, which is sensitive
09:33:30 to the organizer manager field.
09:33:33 So also have failure rotation measurement you can make advances pop is a way to really compare see organized manufactured for us is the turbulent total manufactured.
09:33:47 Excellent, excellent. Also of course sensitive to the cosmic ray intensity normally assume like a competition between the total manufacturer, and as the total pressure off of the cosmic rays.
09:34:07 Okay. Excellent. I'm of the people who've raised their hands I don't know how many of them are responding to this question and how many are asking a new question if you're if you're responding to this question, I encourage you to, to, To unmute and speak
09:34:23 up.
09:34:25 Okay, I could say a little bit about this question, Graham.
09:34:29 So I'm especially interested in
09:34:34 you know ratios in the sort of.
09:34:38 If you look at species, maybe between oh six and down to maybe carbon three especially the intermediate species, what you could learn from ratios of different ions.
09:34:49 And if it's the case that that you can't understand them in equilibrium that try and it will never get them because trying to is assuming equilibrium.
09:34:58 And because then you really have.
09:35:01 And maybe oh six over nitrogen five is a possible thing that's very very hard to explain equilibrium.
09:35:07 And, and then if you can show that that's not the case, then maybe that's a handle on some of these processes.
09:35:15 You know, if you had non equilibrium precipitation versus like you know boundary layer like penguins simulated and.
09:35:25 And I don't know, possibly, you know ionization by cosmic rays you might see certain signatures that can be looking for and I don't know it might be fruitful if we could sort of figure out what those are better than we have.
09:35:40 So that's all I have to say about that. But yeah, I had a question about the polarization and stuff, how far away that Daniel Wang just mentioned. Just quickly how far away from a galaxy Can you do that.
09:35:54 Like a pays off.
09:35:56 Papa 10 kilo plastic scales down to like telepathic skills or less.
09:36:09 No so people can do really well in mapping out of the proposition, and the failure location. Of course the radio, continue hail, which he says to go to the total synchronization
09:36:20 course you're ready to continue and lows and clusters that have seen out to mega Paul sec sizes.
09:36:27 So there are some constraints there but on non galactic scale.
09:36:33 Excellent. I'm sorry.
09:36:37 No, I was just going to comment, put sort of a finer point on something that Todd said you know I agree very much with Todd that you know this alignment of the different ionization stages is really critical to think about.
09:36:48 And I think even even more definite you know we have measurements of the thermal and non thermal broadening of these components, we have upper limits on the size scale of these absorbers.
09:36:59 We also know that they show complete covering so that gives you a constraint on the smallest size scale of them as well.
09:37:06 Or the volume billing.
09:37:08 And so I think that there's actually a fair amount of observational constraint on this.
09:37:13 I wouldn't know how to disentangle the different possible non thermal broadening components essentially in in these absorbers, but I think that there is actually a fair amount to look at that has already been reported observational Lee.
09:37:28 And I think you know some very careful discussions between observers about what they think is robust in their data and theorists about what they think is robust in their simulations or in their analytic descriptions would actually make some serious progress
09:37:40 in this in this, you know, discussion.
09:37:44 Yeah, just to add to that, I completely agree that you know with the, with the velocity components, align for different ions that you know there, there are definite predictions, if you think that you know all these different things are in train in mixing
09:38:00 leaders, even if they come from intersecting many different mixing layers, along a given line of sight that you know they're there are, there should be line ratios, which just depend on essentially two three prime minister cooling time at a turbulent
09:38:18 the few 70.
09:38:20 few 70. And, yeah, you know, I think, you know, mixing layer explanation is falsifiable there.
09:38:27 There are some complications because for example if you compare nitrogen five to oxygen six you have to worry about the nitrogen relative abundance and.
09:38:37 So, so there are some observation alee annoying complications but i think i think it can be overcome. it's an interesting avenue to explore.
09:38:51 I just wanted to mention that there is a important X ray constraint on cosmic ray influence in the Halo.
09:39:00 As you crank up the Catholic rate influence or pressure in the Halo.
09:39:08 At some point, that you get very little in the way of X ray mission as the temperature the thermal temperature of the gas is tends to be below a million degrees, and this is from a model that was published last year, I'd have to look it up, you know,
09:39:30 I thought it was Brian, but in any case, there, there are a lot of X ray observations and constraints on the temperature. And so you can't have so much positive great energy, the gas drops too far in temperature, as we have significant thermal component,
09:39:57 but that depends of the way that are the cosmic rays dominate dominate that are regions. A similar, same as the X ray meeting regions that could be different regions right.
09:40:10 Yeah, you know, I don't think it's it's split up that much mean the calculation of the volume by temperature was calculated.
09:40:22 And it would be in conflict with existing X ray observations by a lot, you know the the on the free parameter in this is the effective speed of the cosmic rays, through the material, and this is, you know, seems to be well known in the disk of the Milky
09:40:46 Way. But, you know, at 50 kilo parsecs above the desk. You just guessing.
09:40:53 As far as I can tell, and people have suggested higher velocities, as you go further out which leads to lower cosmic ray pressures. So, You know, there is that going on.
09:41:09 So, I tend flashed up.
09:41:14 Joshua winners bottleneck simulation, towards the end when he was running out of time, and I will talk more about bottlenecks as advertised on Thursday.
09:41:25 They are kind of an outcome of the self confinement model. But one of the predictions, is that pressure in the clouds is mostly cosmic ray pressure, that was, that was on the slide but it went by, very fast and so the the relative roles of cosmic ray
09:41:43 pressure and gas pressure are different in the clouds and into Cloud medium and broadly that might have some that might be helpful and interpreting observations.
09:41:56 Sure. Very little of the pressure in a, in a cool or warm cloud is going to be thermal pressure.
09:42:05 Yeah, that's an excellent point.
09:42:09 Yeah, it's tricky. It's tricky to be able to distinguish these various different effects which is why we haven't haven't really done it but I do appreciate everyone's input on this, to try and break, break some of these degenerative disease.
09:42:23 I wanted to move on. There have been some very patient. People in the, in the chat here raising their hands. So I'd like to call on digit.
09:42:35 Thank you.
09:42:37 That was an awesome talk being so my question is, yeah when you were just comparing the simulations of Max and Mike.
09:42:47 You were talking that the better way to enter is to analyze, rather than analyzing the steady state simulations it's a better way to analyze the simulations, in which there is an initially turbulent setup.
09:43:03 So, what I think.
09:43:06 Apart from just analyzing this initially turbulent setup.
09:43:14 I accidentally my hypothesis. A more better way would be to analyze a set of where there is an initial driving turbulence, and also there is a magnetic field present simultaneously because.
09:43:32 Why think so, it's because magnetic fields, somehow, change the morphology of the clouds drastically. So, it wouldn't give rise to shatter rings. As we expect in a pure hydro plus cooling setup.
09:43:45 Even with or without turbulence. So, what are your comments regarding this this kind of.
09:43:54 So absolutely, I agree that magnetic fields have to be done.
09:44:00 I guess I have two comments. One is that we have done, magnetic fields in the cloud crushing setup, and the results were very interesting in the sense that, as you said, the mythology is completely different, right look supplementary rather than being
09:44:15 cloud like, but the mass growth rate is almost entirely the same.
09:44:22 Even though, say, you know, the car becomes magnetically dominated the cooling time changes.
09:44:29 That is a rather interesting thing which I have to admit we do not completely understand sort of wave our hands around.
09:44:38 And the other thing is that I also agree that if you have non thermal precious support then shattering by thermal pressure gradients becomes a lot less effective.
09:44:49 But, you know, in these turbulent simulations the breakup is is really more huge turbulence stresses, rather than turbulent brush pressure gradients. So, you know, it remains to be seen what happens but certainly in a cloud crushing setup right where
09:45:00 you might expect, magnetic draping to stabilize Calvin households and to stabilize break up. It actually doesn't you know in the end, the cloud still dissolves.
09:45:16 So I think, you know, when you drive turbulence also, I would expect something similar, but yes, in yen, we have to do it.
09:45:27 Thank you.
09:45:31 I believe you on has been waiting the longest Would you like to ask a question.
09:45:37 Uh, yeah, thank you. I'm a very naive question, but I remember when, when I was looking at these absorption lines. Many of them didn't look quite symmetric to me.
09:45:49 And I was wondering if from that. xml or just from the exact shape of the profiles. If we can tell what's causing the non thermo broadening, and maybe get some idea on that.
09:46:06 I guess this is a question for both observers and theorists.
09:46:10 Can you elaborate, I'm not sure what you mean by the profiles don't look symmetric. Oh, I'm sorry, maybe it's just me, but I haven't looked this metric I completely agree and it's, that'd be interesting.
09:46:26 That'd be interesting. Then, usually you guys just fit a Gaussian, right.
09:46:31 When you have some leftover stuff from that Gaussian fit.
09:46:40 Do you just assume that that's another unresolved component or you think it's some nouns are more broadening that's giving you the a cemetery.
09:46:44 Well, one thing I showed in my talk is that when you see a shoulder or some sort of inflection in an absorption profile at modest resolution. When you look at it at higher resolution, it's revealed to be additional components that are just not well resolved
09:47:02 in the lower resolution data.
09:47:05 So I mean I think that's a reasonable explanation.
09:47:08 Much of the time.
09:47:11 Okay.
09:47:14 I mean, another thing, a point that was made by Linda Bowen and others many years ago is if you have. And I think, Chuck style if you have something rotating you, you might expect to have a pile up of components on one side of the profile and then it
09:47:31 kind of, you know, a trail off toward the other side and so that can lead to that sort of a symmetric distribution of components sometimes.
09:47:47 Um, So, uh, well, let's let's address Daniels question, Daniel you have a question for the panel. Yes. That maturity now from both observational and a theoretical side.
09:48:01 Observation or a way to have quite a lot of evidence for the sale.
09:48:10 Possibly the exploration of particles in the halos of galaxies, based on radio observations, again, and the you, the model basically it's the same car with cooling as function of the distance from the age young Catholics is to ensure a major access, and
09:48:31 as we see coolest stops or flattens at a larger radio I am so my question is the way there's a possible to have an exploration of the electrons, the cosmic electrons at large distances, say, pays off, kiddo parsecs away from playing of this galaxies,
09:48:59 as one specific scenario in my mind is a reconnection of many fields, because basically you have the outflows to vampires the star formation is a disk, yes the natural scenario for stuff forming galaxies.
09:49:20 And then we have met a few that have a turbulence, even termination of the outflows.
09:49:24 And so basically the energy store that is put in some ways in the main field. So eventually as your pants are targeting briefly mentioned actually is the enhancement of metaphysics, twisting and as a folding, but that can be included in Ventura fate of
09:49:44 stored in many theater so my specific question is for theatre theorists is whether it's possible to have the exploration of the electrons, at large distances from the plane, and that way they'll also even possible to hit the gas, you some way whether
09:50:15 kind of gas, with a hot gas or whether it is a diffuse warm gas now so this is my question.
09:50:16 reconnection of magnitude, in terms of how to accelerate electrons, and maybe heats the gas produce thermal heating of the gas
09:50:33 can see a few things. Um, yeah so that's a that's a really great point.
09:50:38 People have thought about, you know, reconnection, you know, suddenly in the context of galaxy clusters Brunetti endless players are in the top. the thought about accelerate re acceleration there.
09:50:51 We are not looking into that.
09:50:54 But, I absolutely agree that you know you know synchrotron measurements are very nice constraints you know we should also look into the Fermi bubbles.
09:51:06 Right. You know how you know how the surface brightness changes with distance for from the shop and and yeah the you know the, you know, that there's a last term for the electrons But otherwise, you know, at the same rigidity, it doesn't matter whether
09:51:21 you're electron or a proton so you know the same thing should apply.
09:51:27 Yeah, I don't know, Chad, or anyone else if you have more thoughts. Oh, and also point says in the chat that she'll be discussing some of this in her keynote on Thursday as well.
09:51:37 But if anyone else wants to address any aspects of this question I encourage them to speak up right now.
09:51:47 I think this is an important thing because this can be directly compared with observations already fair, a lot of this biggest survey of nearby a john galaxy's modeling off was a single coatings away from the major axis of the galaxy associate laugh laugh
09:52:05 with data available, but this fairly the theory available to compare with.
09:52:16 Um, I don't know the answer, but this sounds like a very important question to me.
09:52:20 You know, even if you have turbulence, even if you you know how paying like you showed the cluster case and the ISS turbulence is even more important, even if it's only as important as it is in clusters.
09:52:34 I mean the turbulence goes somewhere right so it has to either heats, and so I guess in most simulations that just ends up as thermal energy.
09:52:57 But maybe that's not a good assumption right so that's probably something we should really
09:52:51 explore like there's a large fraction of an end up in cosmic rays.
09:52:56 Instead, because then I mean, that's not what simulations are doing.
09:52:59 It's going into heating is what's happening right now.
09:53:14 For simulations for individual kind of for the reconnection robbery of me regions.
09:53:15 Baby maybe, which you can pop up all over as a kind of micro kind of recipes, you know, to use.
09:53:24 You will not escape simulations
09:53:30 material and predict you guys have something to add to this or are you asking new questions. And I would like to add something to this, just so I understand that we are talking about reconnection in a more volume filling sense, but there's one situation
09:53:46 is is kind of crazy idea where you could actually have reconnection right at those locations where magnetic field is amplified. I behind those precipitating clouds.
09:53:59 You know, when the cloud is forming it's bringing with it magnetic field. And I have my here, little prop science block which is my headphones, and this is a magnetic field mine and finger represents the cloud that is moving in one direction and so these
09:54:14 lines here are anti parallel, and they are getting closer and closer together and so this is a perfect situation where reconnection should occur when the fields are untie parallel.
09:54:26 And so, you know, you could actually maybe power the filaments. That way, we could definitely have at least in theory, recollection at those sides at sites where energy density in the magnetic field is higher, but it's not a volume filling process but
09:54:41 nevertheless maybe it could be important for the powering of the cold face.
09:54:46 So that's all I want a dog.
09:54:49 I like your prompt to
09:54:53 critique.
09:54:54 Yeah, I agree with materials suggestion, but for two reasons actually one is it's subtle easy to see that you can have opposite he directed feed lines.
09:55:04 Behind the moving cloud. The other is that the gentle CGM is perhaps not magnetically dominated but the cold phase as we've been talking may well be magnetically dominated, and reconnection really is effective in magnetically dominated regions.
09:55:23 So that picture is actually quite nice. So that's about materials, comment, but I had actually a question for Daniel. So, what evidence is there for us to get some sort of Institue acceleration of cosmically electrons observational Lee right so he was
09:55:43 saying he was suggesting that you know beyond 10 k PC. You need some mechanism to insert to accelerate electron. So what is the observational evidence for that in Galaxy Quest as I know.
09:55:56 Yeah, you can major se spatial index of a radio emission a way for s function of the distance from the AGR central plane. So because you imagine the cosmic rays all kind of initially accelerated as the disc propagates out from the, the disk and social
09:56:18 source, should be synchronous coding wins time, edit diffuse out. But normally used to see. Very nice. steepening of the radio spectrum. But, at an artist and become sort of become flattens, you know, said he is a clear indication.
09:56:40 Something is going on with either two ways the manufacturer has the job. great the early, all because as we have kind of re exploration, which kind of keep us up cosmic rays, be still high enough energy to imitate radio image.
09:57:02 So it's basically the lack of spectral cooling, that is, you don't see exactly cooling beyond the distance that means something has to replenish it. Yeah.
09:57:12 Okay. Thanks.
09:57:15 Okay, um, we're reaching close to the time Christophe, you have something to add.
09:57:27 Yes, two things regarding the spectral index, I should add that you have to be very careful about free free ambition that can also flatten the spectral index.
09:57:35 So, not everything that you see is actually synchrotron ambition so that's just my sort of 50% to this point. And regarding the acceleration scenario I have another challenge to pay.
09:57:45 And I would like to see how he reacts it is.
09:57:48 Look at it tastes of jellyfish galaxies we agree this is a perfect depository for very turbulent situation, we know they are electrons in fact we have recently seen that the magnetic field is aligned with the tail we see the similar to the mission there,
09:58:03 and yet it fades away over typical radio pooling time you know what up with an effective tool.
09:58:20 If your scenario should vary, you should see the tape is extremely long elevated and you don't see this in a radio. What is your cooling time that you mean to synchrotron quitting time already.
09:58:23 The synchrotron Singleton cooling length is something that we have talked a little bit of order, a few 10s say 3040 kilo par six. So that's a recent paper written by uncommon I posted it in the chat and the simulations that you have used for these are
09:58:39 great simulations that Martin Spirit that He has recently also published in a separate paper.
09:58:46 simulations. Been Martin spirited he has recently also published in a separate paper. Being a Yeah, in terms of the, you know, this question really depends on the cooling time versus the acceleration time. Right, so, uh, you know the acceleration times of order, you
09:58:57 of order, you know, 10 times that it turned over time. If you are in the sweet spot, and it becomes longer if you're away from that. So, you know, if you have a strong magnetic field, and you have a short cooling time, then you're going to move faster
09:59:11 than you're going to be accelerated.
09:59:15 Just a quick comment. I think some beauty with a john galaxy away from the exes is you will not be confused with someone Mish.
09:59:26 So because you don't see have star formation anywhere. 10 kilometers away from the disk, that's the number one second. For The Reconnection also depends on the pressure.
09:59:46 If it's a basically how much energy you get it into manifested in educated into the reconnection regions with depends are lots of things. I imagine a WAV file away from say is this Jeff Fisher galaxy then the pressure becomes too small.
09:59:59 magic dynamic flows to get into the the connection regions so that also make as a big connection less effective.
10:00:11 And I wouldn't say so because you can get turbulent Rick reconnection there. an hour. I'm. If I'm sure about anything that I think are American simulations of this have too much reconnection compared to the true case basically that nature is because you
10:00:27 know you do reconnect fees on a great scalar, there's a point that as usual, in every simulation that we run so I don't think that we will sort of underestimate this process there.
10:00:40 Rather, the opposite.
10:00:42 Now that the my raise another question I'm gonna want to get too much into here. So with energy work go in the reconnection, you know, with the thermal now thermal, what kind of what kind of energy range, you're talking about be to compare wins observations,
10:00:57 you have to be specific. And now what the fraction of analytical tool, exactly which energy range, because the thermal thermal. So yeah.
10:01:09 Well, that leaves us some, some additional themes to touch on on Thursday.
10:01:15 Thank you very much for your presentation Pang, excellent.
10:01:21 And thank you for our panelists and just generally the audience for chiming in on relevant discussion points, much appreciated.
10:01:30 We will, we will close there. Please join us tomorrow for some awesome tutorials from you only on observational indicators of turbulence.
10:01:40 Searching g talking about cosmic ray effects in the in the CGM Halo and Mathias was kowroski who's going to talk about AGN non thermal AGN effects in glass galactic atmospheres, so that'll be great and then we'll have Ellen is viable will be giving a
10:01:57 keynote on Thursday where she'll touch on many of these points as well, with a panel after her so I'll see you guys tomorrow at 8am Thanks everyone.