09:03:04 Okay, well, I hope everybody is refreshed and recharged, because now it's time for the hot side.
09:03:14 So Jonathan.
09:03:17 Let's get going on how to creation physics of how to creation and cooling flows in Jonathan managed to. Yeah, so, so yes Jonathan managed to escape from Chicago to Israel, so he himself has gone from from very cold to what I would consider hot.
09:03:36 So speaking to us from a warmer climate Jonathan's turn.
09:03:41 Thanks Mark Yeah so yeah so thanks everybody for joining. And yeah, I would like to very much, kind of, thank the organizers for this amazing conference, which really has managed to bought so many great people together and I'm really enjoying the discussions
09:03:58 and I'm really learning a lot so really thanks for that.
09:04:02 And you can hear me well. Sorry.
09:04:05 Yes. Yeah, okay, but
09:04:26 yeah okay so I want to give this to Joel about a cooling flows, a cooling flows is a subject which has been discussed extensively in the literature of the ICM have been a cluster medium, but it's actually how the been discussed in the context of the circle
09:04:28 guy comedian the context of the CGM okay and kind of bridging this gap between the different kind of emphasis is a between the two communities is, is one of the main goals of this.
09:04:38 Okay. And if you want to do it is so just kind of a quick outline of my talk, I just want to first, just quickly go over naming conventions just so everybody's on the same page and what I mean when I say we float.
09:04:51 A, then kind of briefly address. A the me, I think the main observational question concerning Khufu is that, is there a quote unquote problem in galaxies skill halos.
09:05:04 And, Alvin Lee view a basic theory of cooling flows. Okay, that's something that's kind of been developed extensively in the 1980s again mainly in the ice and it's a joke.
09:05:13 And I'll end with something which is the new results, and about the theory of cooling flows with angular momentum, and specifically how you could impose a creature on to the desk.
09:05:22 Okay. And I put a teaser here, if you will remain to the end of the oil. That's the answer depends qualitatively on Edelman's.
09:05:32 Okay, so let's start.
09:05:34 So first, naming conventions. Okay, so first when an ICM expert says a cooling so I mean somebody like but the Sharma Oh Malik Boyd, okay. He means something like he means that the whole hot Hedo is influencing toward the center of the potential.
09:05:51 Okay.
09:05:58 And now, the guest is recording so that starts in inflow okay but as it's influencing it's being compassionately he did. And this competition like eating enough he balances that are native query.
09:06:03 Okay, so in according flow in these classical inflows, the gas temperature actually remains off the constant and the gas is only losing entropy.
09:06:12 So since eventually what's being eradicated is the oppositional energy, the influence what kind of in these kind of classic flows, is the luminosity over the difference in gravitational potential.
09:06:24 Okay, so that's a, what I call a classic cooling flow and that's what the ICM people say when they meet me. what I say mean when they say clink.
09:06:34 In the senior middle of all these over already seen something like this called a coin flow. And this is kind of the general a flow of gas in temperature space and form a high temperature to low temperature.
09:06:48 Okay kind of without specifics of location. I've seen a lot of discussion of this a for example in epic wins and Jessica works people. And this is also called the cooling film but it's something else.
09:06:58 Okay, this is guests which is actually cooling it's actually losing thermal energy, and therefore the that infiltrate through the flow and temperature space is the luminosity divided by the difference in specific specific thermal energy.
09:07:13 Okay, so, I seem to also this been called gleeful but this is something very different from kind of these classic.
09:07:20 Okay, so it's just kind of very important when you read about something to understand which one of these, this is, and of course if you like to be kind of specific to what you mean.
09:07:29 And of course there's also cool flows which happens similar name but very different thing. And this is of course what Neil discussed, okay these are just gas flows which I love you have equilibrium temperature and the flea foot.
09:07:46 Okay, the mass insulated selfie the mass divided by the freefall.
09:07:44 Okay, so kind of similar names but very different things. Okay so cooling flows is essentially a type of hot accretion and co flows or force a cold.
09:07:54 Okay.
09:07:55 So that's just a quick kind of older than the naming conventions in naming conventions, and from now on, all I'm going to talk about is the classical info okay what the ICM people called workflows.
09:08:12 Okay.
09:08:09 Okay.
09:08:11 Okay. So before I kind of I you reach the cooling full problem in the CGM, I want to just briefly, put everybody on the same page and what is the cooling formula cooling flow problem in the ICU.
09:08:24 Okay. And so basically the idea the clinical problem which is a 14 year old problem is that if you look at the excellent mission from the ICM you assume it's an accordion flow, you can derive from the X ray mission, what is the influence.
09:08:38 And then if you compare this in Floyd, to the star formation ringcentral galaxy. The difference by between one and two orders a match. Okay, so you just have you're seeing Yes, which is on a recording, which is implies a huge inflow, but then you don't
09:08:51 see this guests piling up performing stars at the center.
09:08:55 Okay so, and the immediate consequence of this is that kind of the guest is not actually influencing in there's some heating bill, but potentially by agent feedback, which is kind of replaced replenishing the energy that gravitational energy last who
09:09:16 are the two.
09:09:12 Okay.
09:09:13 And a kind of standard model for the ICM is called a film of balanced water. And the reason is because you have to assume that the heating of the ICM will actually account for all the Kool Aid because the the amount which actually form stars is such a
09:09:30 negligible amount of the total cooling. Okay, you need the healing to entirely compensate for the
09:09:36 aim. So that's the problem the ICM one kind of anecdotes which is not the focus of this early, is that not all clusters have a cooling flow problem, if you look for example, on, on a phoenix cluster which is the star on the top right of this figure.
09:09:50 Okay, it's influenced by the excellent mission is actually comparable to the information.
09:09:56 And actually if you look also at other properties of the ICM a they also resemble cooling flows. Okay, so if we want we can discuss that further into discussion, but at least most a galaxy groups in clusters, a full inconsistent with workflows and acquire
09:10:14 some kind of filling abundance.
09:10:16 So that's the ICM. And what about the CGM.
09:10:21 Okay, so this is a similar float for a the CGM okay so okay the extra Michelin star galaxies, okay so around us like it's much harder to see the X ray mission, but it's still possible for a fruit local bright sources.
09:10:38 And this is a compilation by King County, and a basically what he did it again he took the extended the mission, allow local Estelle galaxies calculated from that, what is the expected in Floyd, if you assume before it is low and compare that to the star
09:10:53 formation and the dashed line here is a, the one to one relation, but most of the axis here are inverted relative to the previous one. So here the star formation rate is on the horizontal axis and kind of the influence the expected in Floyd is on the
09:11:09 vertical axis. Okay.
09:11:20 And the situation is very different from India, yet. Okay, essentially, you can see that stuff formation rate is comparable or even larger than the influence. Okay, so there's no direct evidence for quoting flow problem in style galaxies, as there is
09:11:32 Sir, as it is in kind of galaxy groups and clusters. The X ray situation is very different.
09:11:37 Okay, so, and another way to put this okay essentially is that if local installed galaxies had a queen full problem. Their X ray mission would be much brighter than actually observed okay that excellent mission would appear kind of on the top left part
09:11:58 of this plot, and a, it would be much more blacker in the X ray than we actually. Okay.
09:12:14 So at least my conclusion from this is that film and balance is not required by data by the X ray data, and we should consider the possibility that the hot CGM in the hot fixes em is actually info okay because we don't have kind of a strong reason to
09:12:16 believe there's a lot about, okay, I'm not trying to say that film imbalance in the hot seat units will doubt, but it's definitely not required by the day.
09:12:26 And. Okay, so just kind of to put this conclusion in the context of this cartoon that everybody likes to use as a punching bag. A, my, my point is that kind of this diffuse phase okay this volume feeling hot fees in the CGM.
09:12:39 Okay, is potentially influencing and feeding the this. Okay, not condensing and then cool clouds feeding this, the whole hot volume three phases in flowing and feeding the day we should cook.
09:13:11 Everybody else seeing, Jonathan frozen.
09:13:14 Yeah.
09:13:17 Jonathan you froze at a crucial moment. You were saying that the diffuse the whole diffuse Halo is in flowing non condensing into cold clouds and then you froze in this very emphatic pose so maybe you can go back and and keep going.
09:13:36 Sorry, it was that here was that in this slide, that was on this slide yeah right at the beginning it was absolutely I was riveted and then you just throw, throw it out here you said this cartoon is a punching bag.
09:13:51 First, just to be clear, I'm not saying it's necessarily and flowing okay but I'm saying we should consider the possibility that the volume filling phase is kind of in flowing into the central okay that's, I think that that scenario which is kind of worked
09:14:06 worked out in the ICM is definitely not ruled out in the CG okay that's my main point.
09:14:14 Okay.
09:14:19 Great. Okay, so that was kind of the, you know, that was kind of the background with me just so I see I don't freeze. Okay. Okay, now I see Jessica and then I know I'm not freezing.
09:14:30 Okay, great.
09:14:33 Okay.
09:14:34 Okay, so, so now a little bit about the physics of. Okay, so I hope we can convince you that it's at least possible that the hot CGM phase is influencing feeding the desk.
09:14:45 Okay, now you can ask the question what are the properties of this hot TGM if it is in fluid and. And this is something again that hasn't been discussed a lot in the context of the ICM mailing the 1980s.
09:14:58 What's a I did together with a German fielding is kind of adapt the results that will drive in 90 days for the ICM for CGI for the hot CG. Okay, so this this plot is a plug for my paper, it basically demonstrates is some of the expectations of a hottie
09:15:19 GM which forms according to what you see on the left is kind of snapshots from a Drummond's idealize CGM simulations. And basically, we assumed a hot Hello, sorry we assumed a potential and put in inside Yes, which is hot and initially hydrostatic, and
09:15:39 we just live it.
09:15:43 Okay. And you can see here snapshots from different times in the simulation. On the left you see temperature, and on the light you see in Florida and velocity.
09:15:52 And you can see that the gas. It kind of remains hot, and a, kind of, it forms kind of a very mild inflow. So, can you see my, my arrow, my cursor. Okay, great.
09:16:08 Okay, so if you look, it looks for example in the end user profiles for can legally average profiles. Each sort of line is a different time in the simulation in the initial there is no info the initial conditions are static, and you can see the effort
09:16:22 some time, you get kind of this very mild inflow of the one solar masses per year in the industry knowledge.
09:16:32 Okay, the velocities are very slow it's only like 20 or 30 kilometers per second, the info is very mild it's very sub Sonic so much lower than the sound speak.
09:16:41 Okay, but the point is because there's so much mass in the hard phase gate this info could be significant for feeding the guts, another result here you can see is that the temperature of the mains Lafayette the video damage.
09:16:53 Okay, so this is what I showed you before, that the guest is cooling, but because it's in flowing, it's being completely heated. And these two of you compensate for one another in there for the guests that means hot.
09:17:05 Okay.
09:17:05 And the third property which is kind of probably the most important point of view, going flows, is that the flu time are over the radio velocity is roughly equals the Clinton.
09:17:15 OK, so again in the initial conditions the flow times infinity because there's no velocity, but very quickly, you reach a solution or a scenario where the flow time equals the cooling time, and essentially the gas speech is the center on a, on the quit.
09:17:32 Okay, so that's kind of a very basic description of what cooling flows, and what pulling flow those that's been discussed a lot in the ICU and.
09:17:45 Yep. Okay, so I gotta put here a few more possibilities of cooling flows. A just kind of briefly mentioned them and I think if you want we can discuss them further in the discussion.
09:17:57 A. So first, the formation time of recording flow is the community. Okay, so if you think you have some kind of burst of feedback some strong heating effect.
09:18:05 Okay, which kind of stops the cooling flow, you can ask the question, how much after how much time the cooling so reforms and and that actually turns out to be a very short time in the inner CGM where the Queen time is only something like 300 mega.
09:18:30 ok so if you have a bill city, a dusty feedback scenario. Okay, then you will have kind of a cooling flow being reformed again and again and again. Okay, so it's very reasonable especially in a galaxy like the Milky Way or similarly, this is galaxies
09:18:48 at least the email CGM is for farming equipment, and other important things that the flow is very sub Sonic and said before getting me to the Punisher profiles are a clue for a very close to hydrostatic. Okay, actually do the first order that actually hydrostatic.
09:18:52 hydrostatic. A. Another thing is that the feminine instabilities which grow on acquitting time addicted also on according time.
09:19:01 Okay so feminine instabilities including flow don't have time to grow because they're addicted on the same timescale that they're wrong okay so generally if the hot phase forms of cooling flow.
09:19:11 Okay, we don't expect it to kind of naturally form multi-phase gets, can we expect well the fee structure, only near kind of these large disturbances, like satellites or filaments or this okay kind of the the volume filling phase should not be multi effects.
09:19:27 And of course there's this prediction for observations that dense the scales off yes are the minus 1.5, and which means a bit the parameter of point five.
09:19:42 So this is prediction which can be compared to, x ray observations. Okay, so that's kind of generally quoting flows, without angular momentum and this is all kind of relatively old stuff just we kind of apply them to a CGM and I think there's a lot to
09:19:53 test in CGM studies using these results in that last part of the talks what happens to quitting flows, when you add Angular moment. Okay, and this is based on recent work that I did together again with it from I'm feeling.
09:20:09 And so we have hot gas which is influencing him, and in a cosmological scenario this hot, hot gas should have Angular moment. Okay. So at some point when the radius become smart enough, angular momentum support should be significant.
09:20:26 So what happens in these kind of, when you assume an angle is that the hot flow, kind of stalls at the angular momentum radius, a kind of converges onto the disk.
09:20:35 Okay, so what do you see in this in the spot is again, this is a snapshot from Germans idealize CGM simulations, you're seeing ua the flow lines projected on the outfit the plane is where the, the guest is actually rotating in the feed direction.
09:20:53 Okay, this is the plane of this curate data equals pi over to.
09:20:57 And you see that the flow is kind of radial at loud scales and then just converges. On to the disk. Okay, so what the angular moment does is that essentially stones the quick.
09:21:08 Okay, they could have in principle just continue to flow in Word into smaller and smaller lady I, but because of angular momentum, it will install here and eventually caught on to this.
09:21:19 Okay.
09:21:21 So if the hot CGM forms a clue flow, it's just that the inner hot Halo is rotating okay lovely at the circular velocity, and that's the jet and that's consistent actually with observations of a of the Milky Way.
09:21:35 And another interesting question, is the fact that is the guests are important is that the guest, who's just before joins the disk. Okay so that might have interesting predictions for excellent Planet h1 or for HPC.
09:21:47 That's something we need to look into more.
09:21:51 And one more point I want to make is that a, this is the dominant creation mode in the fire simulations of Milky Way mass halos at Norwich okay so this is definitely.
09:22:02 This is definitely how kind of Mickey way mass low budget halos a cretin fire, and that's kind of a paper that is actually being which is still in touch.
09:22:12 Ok.
09:22:15 Okay, so just got to put this in context of other models for locating hot corner. Okay, so this is something that came up a lot in this conference and I'm very glad.
09:22:24 Okay, that there's kind of been some kind of people look into the fact that the hot Hedo of Mickey with Nike galaxies is rotating.
09:22:33 So first this the observations, okay this is this is from logical model by Edmonds based on the kinematics of oh seven absorption, through the Milky Way.
09:22:42 Hello, and he actually deduced that the hot Halo is likely a loyalty. Okay, so first kind of very strong observational evidence.
09:22:50 And then there's these hydrostatic models in by MIT so money okay so basically what they assumed is that the hot potato is taking him, but it's static it's not in flowing like in our metals in.
09:23:05 What do you see here is essentially a profiles of specific angular momentum and their models. A these models are actually pretty similar to all models or our model similar models.
09:23:15 Because, as I said before, because the inflow in our models is very is very mild very sub Sonic, the pressure profiles are really close to hydrostatic.
09:23:32 And of course there's also evidence for hot hills we're taking a also in kind of illustrious, and any guesses paper by Ben, and if the police in.
09:23:44 Okay.
09:23:51 How much time do I have. Well try to wrap it up in a few minutes for discussion.
09:24:13 Okay, so I have one last one last point so I will jump into that is how do the cornfields depend on hazelnuts. Okay. So, in what happens in these cooling flows, is a what you get from if you look at a clue is that the ratio of the cooling Tyler free full
09:24:16 time decreases in words. Okay. So if you have a perfectly they do cooling flow at some point the cooling, at some small radius the cooling flow will drop below the freefall time.
09:24:25 Okay. And once the quintet drops below the three full time compression can no longer more, a compensate for the ladies.
09:24:33 Okay, so at some point, the hot, a hot gas, it will essentially turn into a cool supersonic flow.
09:24:42 Now, it makes a massive he knows, kind of the the Khalifa which is the angular momentum radius before it reaches this, this point where the Queen type equals the free full time.
09:24:52 But when you're the nomads halos. Okay, the transition between kind of a sub Sonic, a hot info with cooling time larger the freefall time to a supersonic cold flow with Queen time shorter than three full time happens on the CGM.
09:25:05 Okay. So, cooling flow in relatively massive Hey nose, kind of gently settle on the disk with the Super Sonic flow, what in nomads heroes the subset including flows first turn into supersonic cold flows, and then crash into the disk.
09:25:21 Okay, so they go through a sonic point and then crash into the disk. Okay, so there's kind of a qualitative difference between how cool for work when flows work in a milky way mass halos, and in lower methods.
09:25:34 And I'll just kind of make quickly the point that we identify this transition in fire in the fire simulations and this transition between kind of these trans Sonic Queen folks to subsequent flows is associated with the suppression can have a supernova
09:25:49 live and outflows.
09:25:52 and outflows. And I'll end with that. Okay, and maybe I'll just leave my summary here.
09:26:02 Okay, thank you very much. I will applaud live.
09:26:10 And will there are some questions already accumulating in the slack, and I will also look for hands in the zoom chat.
09:26:22 I see there's a question from Jess, that says, For the cooling flows the models seem to also create velocity and temperature profiles correct and it seems like at 100 kilometer six and beyond the temperature is a few times tend to the fifth question mark.
09:26:40 Hey.
09:26:40 Yes, so that was predicted very clearly. What is the temperature profile, it's essentially equal to the gravitational temperature what Mark, called the gravitational temperature and it's totally out a few weeks ago, it's at the video temperature or lovely,
09:26:56 which is proportional to the circle of last square. And at 100 kilo robotic specifically the quitting time could be very long, so it depends on who kind of applies only where the quitting time is shorter than the Hubble time.
09:27:08 So it's kind of questionable at 100 kilobits, but generally yes you can tell from a cooling for social what is the temperature at each rates.
09:27:17 Okay.
09:27:33 And, Todd trip has asked a question that has received a bunch of replies that already, which is what why is low ionization gas including a variety of metals found at large impact parameters with high covering fractions.
09:27:34 Yes, that's a great question. Yes. So, first when you say loud you back parameters. Right, right, kind of, the question is, what, you know, when you say logic right so what do you mean okay so if it's if it's gas, definitely some of the gas comes beyond
09:27:50 the equation shock, and in there, I think, you know, there we expect cool Yes Get a cooling so kind of only happens within the video the shock. And I think it's kind of a question will be coming closer.
09:28:04 And, but I guess I guess it could be also, you know, could be satellites could be a could be any if it's if it's a cooling, if it's a cooling flow it won't cool guests won't spontaneously.
09:28:28 Yep.
09:28:28 Okay.
09:28:26 Job brakeman has hand up.
09:28:28 Yeah.
09:28:28 Yeah. Come on, honey muted.
09:28:31 So, you sound the things that were suggested, you know, in the, in the various years about cooling flows, was that there would be enough in the way of disturbances
09:28:47 that there would be.
09:28:51 Thermal instabilities that would grow it a large radio, because the, the mass loss from, from dwarfs or stars or inflow would lead to such behavior.
09:29:06 And that doesn't seem to be present in what you show.
09:29:11 So was that is that just too much micro physics or.
09:29:19 Can you elaborate joy. Yeah, I'm not sure I understood the question.
09:29:25 So, yeah, so, um, when people were doing.
09:29:32 So it looks like the cooling rate.
09:29:37 Certainly is the is the radiative
09:29:43 rate.
09:29:44 But, you know, the, you can have thermal instabilities within certainly within the compensations is Mark well known.
09:29:55 Within the cooling radius, which is you know twiddle 100 kilo Paul sex right.
09:30:04 And, but it looked like the simulations and we were showing
09:30:11 didn't seem to have those. So,
09:30:16 so definitely you know if you have a very pure quick flow. Okay, then you won't, and you don't have any sources of, kind of a older unity, a density fluctuations.
09:30:33 Then you will they won't naturally form. Okay, now there's a question about the organization gas, you know how that we see an observation How was it for.
09:30:39 So it can form, due to near the disk conform to to fundamentally conform to the celebrates like as DOMA discusses many reason, where these instabilities can fall.
09:30:49 Okay, my point I think for the Queen flow is that they should not these ionization to learn ization gas should not be volume filled. Okay. So I think what a trip said that the covering factor is very loud that still does not tell us that the loan ization
09:31:00 gas is volume.
09:31:10 Okay, I think, you know, it could be confined to that to be reasonable regions in the, in the hill.
09:31:18 It's not definitely in kind of like, you know, make you a more massive galaxies and definitely have large Empire parameters we don't, I don't think we have evidence that you have glue Yes, everywhere.
09:31:31 Okay, we know there's a large a we have a couple infection, but that doesn't tell us what the volume thing actually.
09:31:40 I would say that observations, such as a catch box of observations would show that no innovation gas is maybe a mo along a minor axis major axis and less like an intermediate angles that actually suggested, you don't see Lauren is that there's not cool
09:31:56 guests everywhere. That's only needed disturbances, like the disk, and I guess I was asking you to reconcile the models you showed without of one the mall void, which seemed to be somewhat different and somewhat more complicated.
09:32:14 In terms of the radio distribution of cooling material.
09:32:23 Like I say, first.
09:32:39 Yeah, good comment, I'm still, I think observation show that it some significant in height, you know, t cool is longer than T freefall in the volume filling phase.
09:32:40 And if that's like rate dynamically quiet undisturbed. You don't expect thermal instability to progress.
09:32:50 But if there is some disturbance, then you can get condensation to happen. So in an idealized simulation, you don't, that gets a single phase until you cross into the region where, you know, t cool is less than t for evil.
09:33:06 But as we see in cosmological simulations. There are many different forms of disturbance that could cause the gas at large altitudes to be multi phase, even if t cool is longer than two freefall is that the parsing you're looking for Joel.
09:33:24 Yeah, yeah, because you know the distributed cooling lowers the cooling crisis that you show where within 30.
09:33:41 And it's not obvious that one sees that, but nothing Milky Way Matthew, the catastrophic cooling off will only happen it's lower mass halos not making a mess.
09:33:52 He knows the gap will remain the hots kind of down to the disc.
09:34:05 When we look at galaxies both elliptical and spiral. The gas temperature is usually about 50% higher than the variable temperature.
09:34:17 And actually, that would be needed as you raise the temperature, the value of beta decreases, and you would need a hotter temperature to have a beta of a half gas so you know Milky Way galaxy.
09:34:36 2,000,002.4 million degrees is the main temperature that seen yet the variable temperature is on a 1.4 1.5.
09:34:46 million. And that's very typical.
09:34:51 I mean it's definitely didn't I mean that equality with available temperature is kind of is off, right, and it will be going into factors definitely a reasonable, India, particularly depends on the pressure gradient.
09:35:03 But let's move to a question, as young Tell me.
09:35:08 Okay, since this is a very nice talk.
09:35:12 Well, my question is mostly based on the related to the show, or feedback in this quoting flows. So I just wonder.
09:35:23 As you show in massive galaxies, including gas is keeping hot, so I guess, in this case, the feedback may not be very efficiently heating the employee, gas, so it may not have really important effect on the inflow, but he low mass galaxies, as he will
09:35:41 show the inflow can become supersonic as a guest can crew, or in this case, I just wonder, will the feedback player yo yo heating the employee gas, and finally take back to outflow dot.
09:35:58 Yeah, so I can tell you what happens in the file simulations.
09:36:02 Right. So in the file simulations, like when we're in the Snowmass Halo regime where the cooling flow at small scales turns into a supersonic flow, flow, you have lots of very strong feedback for a strong outflows and this kind of outflows, they both
09:36:27 of mixed with the inflow cooling yet the cooling flowing Yes, and they also affect kind of the hot gas at larger idea. And so, yeah, it definitely has an effect it also kind of creates these instabilities there's definitely a feedback back.
09:36:36 I think kind of you know that the, the main kind of the main advantage of the query flow is that it's, it's, it's the baseline state of the heart. Yes, okay, if you think about like what happens in a disc, like the Milky Way is questions okay and if you
09:37:09 depending on how much in assuming that a GM feedback is not super much eating the gym, then you would get equity So, okay, any deviation from according so would be due to feedback, okay and the Cooney so i think is a very useful he has a baseline caused
09:37:11 by by star formation feedback, because we are talking about a low, low mascara.
09:37:18 Yes, no rest galaxies yes and I, I guess my point is that the these kind of models going for models are very useful as a benchmark for how the hot X ray is CGM behaves.
09:37:29 Okay, so any deviations would be due to feedback or due to other complexes, a complexity is kind of in cosmology nations but they give you kind of what is the zo their behavior you expect for the hots the gym.
09:37:45 And, you know, we should compare observations to these models, kind of understand where these models work, and that means that feedback is not very strong and see well they don't work in that kind of stuff just the feedback is strong.
09:37:58 That's kind of I think the main point I'm trying to make.
09:38:01 Oh yes, I just a gas maybe in the relatively dinner Hello, of the CGM so what you had seen is probably dominated by outflow instead of inflow, but I lottery I may be influenced on.
09:38:16 What do you mean dominated by outflows inflow I mean, the gas isn't mostly just how slowly.
09:38:24 I to, for example, typically within a few 10s of Quito politics from the galaxies.
09:38:31 Yeah, I'm not sure what it, what are you referring to we need simulation for a show these kind of ideas you mentioned there is no outflow everything is an inflow.
09:38:40 Okay, on fire. We have gotten in the Indus again we have a mix of inflows and outflows.
09:38:47 Okay.
09:38:48 Okay, since.
09:39:03 Sorry, I think I was muted.
09:39:05 Rosie Talbot from the slack ass Do you expect magnetic fields will alter the picture significantly, would it change the angle of gas that reaches the desk.
09:39:15 That's a. Yeah, that's a great question. And, yeah, I mean, what happened. Yeah, that's if anybody else wants to answer that lb let me know Yeah, basically I think you know as you're in flowing with the magnetic fields, they will become stronger at small
09:39:31 radio. But what would be exact effect that would be a great thing.
09:39:36 Conveniently has his hand up.
09:39:40 I could, I could comment on, on this but I was going to ask a different question actually.
09:39:46 So, I want to come back to what Joel asked and whether there is a full consistency of the result with.
09:39:55 Let's say you want these results or anybody else's who simulated thermal instability on these in flowing blobs So, as far as I understand well not only can correct me these idealize simulations don't include any heating sources right, it's just cooling
09:40:12 and the rotation.
09:40:13 Yes, it's not so in that case, I think, standard or classic result by bubbles 1988 applies.
09:40:22 And what was demonstrated in that seminal paper is that you don't actually expect any fragmentation and instability basically standard as American stability is not expected to occur and that's fully consistent with what you're seeing in your simulations.
09:40:39 So, if you get detected, just to kind of be clear it's it's a vector right so until they go there already a directed kind of towards the center.
09:40:48 Okay.
09:40:49 There's no instead, the gas is still me and stable but it doesn't have time to grow until it goes to this right but sorry.
09:40:56 Yeah.
09:40:58 And actually, since I have the floor now for a second, sorry about that other comments are related to magnetic fields.
09:41:07 I think they will make a huge difference and we we've seen this, for example in challenging simulations where magnetic fields get selectively amplified the locations are condensing gas.
09:41:20 And even though you start with the very high plasma beta parameter, you end up selectively amplifying fields right where the blobs are right where the condensing gases and the impact can actually be severe.
09:41:32 And you can get rid of any discs that would otherwise produce or get generated in the center of these potential well so I would expect the impact to be very significant in an interesting way.
09:41:45 So that's just a comment. Okay. And maybe frica has. Yeah.
09:41:50 Yeah, I'm not sure. So, so we have done this experiments and so have sort of others to whittle them as recently also put out a paper and and both of these works fine that.
09:42:16 you said either the galaxy so. So, I mean those, those rooms me simulation so it's not infinite statistics where we have now have like, about a dozen examples where we were there hydrodynamic simulations have a smaller disk with a very
09:42:29 strong cut off sort of where the disk where the gas disk ends and also, I mean that has consequences for the stars that form from this gas this of course.
09:42:39 And for more extended
09:42:43 stellar discs and then depending on how you define you know your disk to total ratio so my work found that the disk so more prominence or higher dispute total ratio, but there's also other kinematic ways of determining what you're discussing so we're
09:42:59 getting a middle found that they are very similar in the district total but still different than the extent.
09:43:05 So I would say that magnetic fields are likely to increase the angular momentum of the recruiting gas.
09:43:16 So, you want has a question in slack and her hand up, how does the hot guest join the cold disk exactly does term CSM scoop up or down the hot gas and mix all cafes and we aren't is that question you still would like to ask.
09:43:29 Yeah, but maybe I can make a comment first just to add a little bit on to what what Joe raised and what Mattel said, and I totally agree with Jonathan and Mattel so so even if you do a simulation without perturbations, you will just have a pure quoting
09:43:50 flow that's normally stable and recording will only happen the very center, and maybe another way of looking at this and I think drama fielding also pointed that out.
09:44:01 And this is how I looked at it at least is. So, and then my first paper in 2012.
09:44:10 I looked at the quoting time, and the, the, the heating time due to congressional. It's congressional heating time. So as the gas flows in Word, it gets compression or a heated and that perfectly balances cooling and the and the classical flow.
09:44:30 So, you only developed amongst the bullies when you start perturbing this hill.
09:44:37 What I would also like to add that even in the cases where you think there's a lot of heating, for example, in the ICM, one can still view the hot face as being.
09:44:52 Well, in a reduced cooling flow. And this was also nicely pointed out and carrying on paper, I think, maybe it was Mateusz, where she looked at the, the part where the Jets are not hating directly, so you can basically call that a cooling flow.
09:45:13 So the guys is still flowing words, and you can have regions that are not developing local instabilities.
09:45:21 Oh yeah and I have a question on slack about how exactly how exactly the hot gas joins the SM.
09:45:32 Yes, so kind of at least yo this is something we were still looking into, but at least what we're seeing, most of the idealized simulations and in fire.
09:45:41 Is that just before we joined that this gets cool results. Okay, so the completion that he didn't kind of continues just until a few scared of heights.
09:46:08 So, and, you know, hopefully we'll have kind of more quantitative results, but it shouldn't be some kind of cool gas above and below that it's okay, which is influencing towards this. So does it cool over a cooling time, or does it cool, more quickly
09:46:28 look at that.
09:46:27 So, yeah, so first Dolan simulations is actually a good grid code, but the quick game is super short right because we're talking very close to this the guest is very good.
09:46:37 Okay, so it can cool very very quickly and it even becomes denser because it's, It's all dating so it's not slightly similar.
09:46:45 Yeah, so it should be some kind of cool guests which is right so it's hot.
09:46:51 It's a hot inflow down to maybe 1015 kilo parsecs, which then turns into a cooling inflow onto those, That's kind of the picture.
09:47:02 Right.
09:47:03 It's Greg Brian as in slack a question, which I might have asked myself, which is what sets the mass accretion rate in the cooling flow, because in the absence of feedback, a cooling flow in a regular cosmological creation would be having a much larger
09:47:18 magnitude.
09:47:20 Excellent. Yeah, so thanks for the question. So, basically those one fleet parameter in these flows, or let's say two three pounds. One is the gas mentality.
09:47:28 And the CGM at Liberty, and the CG total CGM that's okay so for example if you think about know that shift make you a mass halos. Okay. The, they'll make the liquidity, and they'll mass or probably said by feedback at higher rich.
09:47:45 Okay. Once those are set, and you know these two bundles then you can kind of predict what is the influence.
09:48:01 You need the hot CGM to be maybe 10 or 15% of the bottom budget.
09:48:09 So, lower than kind of by incomplete.
09:48:13 So this is, whatever sense it has already happened by the time your model comes into play.
09:48:21 Exactly.
09:48:25 Near. Yeah. So I guess I was wondering, Jonathan what what your thoughts were on how we might be able to, I guess, two questions. One, how we can observation Lee perhaps distinguish them and to what might the difference be in terms of the Christian under
09:48:42 the galaxy and subsequent star formation between cooling flows which which, you know, I think we would all agree or are likely more dominant this on average, low z as opposed to the cold streams which which are at least theoretically, on average, more
09:48:58 prominent at high Z, but how can we really, or can we really tell them apart observation Lee and what might the different effects on galaxies be.
09:49:08 Yeah, what one big difference. You know what you guys talked a lot about is kind of the turbulence induced in the disc, right. So, in these sub sub including flows right, everything is sub Sonic causally connected.
09:49:20 Okay, that they, the inflow knows that the disc is coming.
09:49:23 Okay, and so it's a very gentle kind of settling on this. And then when you have these streams or even when you have kind of these, quote, unquote floats right then everything is supersonic not complicated and it's much more increased turbulence in the
09:49:39 disk. So, at least in fire. When we see this transition kind of between a cold flows to kind of be substantive how efficient, the DC becomes much thinner and it becomes kind of much less turbulence, and much more fun.
09:50:04 Yeah, so that's, I think, kind of the main effect.
09:50:00 So there's a question in slack from one young john were the first part, I think you've answered, but the second part is how does the hot gas coin flow and the cool gas going slow car lead.
09:50:14 Yeah, I'm not sure right, I fully follow.
09:50:18 Okay.
09:50:19 How the crew. Yeah.
09:50:21 When you say the phase. You mean, when the cooling flow kind of entirely chorus out into a supersonic flow.
09:50:31 Yep, and it would just crash into this. Yeah, maybe you can unmute and clarify.
09:50:46 Good. Well, all right, or maybe clarify in slack and meanwhile, I'll have a Joel ask a question.
09:51:01 I can't hear Joel.
09:51:05 I could.
09:51:07 Um, so one of the things that I had a student tried to do was look for flattening and of X ray x rays, in rotating galaxies, because one would think you, this would be easy to find.
09:51:25 And actually it's very hard to find.
09:51:28 The you can always find some galaxies that are not perfectly circle and x rays but I'm so I'm wondering if angular momentum, gets redistributed in the inner part.
09:51:43 You know, one needs a,
09:51:48 an effective is constantly but their magnetic fields, I mean the variety of things. So that was one question let me ask the other questions. Well, I think this is mainly.
09:52:00 Well, it can be both observers and theorists.
09:52:04 So, the return of maths from aging stars and galaxies today like the Milky Way is almost equal to the,
09:52:19 to the star formation.
09:52:22 And, you know, when you add in one or two solar masses a year cooling from a halo it exceeds a star formation right. The implication being that the disc would be growing in mass and possibly size depending on the angular momentum.
09:52:39 So this seems like a question that or constraint, eventually that one can answer.
09:52:46 And so I just put that out there to to raise that issue.
09:52:52 Thank you.
09:52:54 There's a question from Yaakov Thurman query flow models or third balance models can both be used as baselines with the other set of money has been the deviation do the presence or absence of feedback respectively, where does the cemetery break What can
09:53:08 one set of models do that the other cannot.
09:53:13 Yeah, yeah, yeah, I guess kind of the advantage. Yeah, I wouldn't say that the difference between the flow model and the other models like like your model and like that plus coefficient economic model.
09:53:34 of the gas, and according flow is the effect of feedback. Okay, so you, you can use a quoting flow to kind of learn how the hot gas has changed due to feedback.
09:53:43 Okay, in.
09:53:45 Right, so, because the clean food is just kind of this basic state of a of oxygen okay no feedback, you would get a quick drop.
09:53:56 So that's kind of That's for me the difference right it's more like a conceptual difference. Okay, it's what would it be like if I was having simulation in which are trying to understand what are the effects of feedback, like, like, like I do with fire.
09:54:12 Okay, just compared to the hottie gentle couldn't, rather than compelling it to a, let's say yeah come to your model. And then I know if your model is correct or not but, you know, because it has assumptions on feedback.
09:54:25 Okay, it's, it's different than cooling so which is just get without.
09:54:30 I hope that answers the question.
09:54:33 Okay.
09:54:38 Um,
09:54:38 well I, yeah. Does anybody else have a question for Jonathan, or questions for near.
09:54:46 We're five minutes to the end of our two hours.
09:54:53 All right, I'm hearing no other questions.
09:54:59 I want to thank you both and also making the announcement.
09:55:03 There is going to be an after party tomorrow.
09:55:06 It is the sZ CGM after party.
09:55:11 And I The time is Ben Can you remind us of the time.
09:55:15 Yeah, I'm 11am Pacific So, and if I think I can confirm that so that's right after the active deprogrammed tomorrow.
09:55:30 That's the power of us to what.
09:55:33 When we finish at 10 so it's an hour after that, oh yeah that's right, I am sorry.
09:55:38 Yeah, mountain and there is a gap. Yes, thanks, Cameron. So, yes 11am is the cap I was replacing mountain and Pacific, as I always do because you're one hour apart.
09:55:51 So, yeah, please do join that and that's even better because you have a break for lunch or dinner.
09:56:01 Depending where you are.
09:56:03 Okay.
09:56:07 So tomorrow. Then we have do Sean Parrish.
09:56:21 Giving us another keynote talk this time, a simulators point of view, one, how does gas flow into galaxies. So until then, have a great time.
09:56:29 Thanks everybody, very much. Jonathan and near excellent tutorials. Thanks very much. Pleasure.