09:10:08 We've already reached 10 after the hour.
09:10:11 So hope you all had a real nice long relaxing break.
09:10:16 And I'm going to ask our panelists to prepare to discuss the talk and what I'd like to do.
09:10:25 I'd like the panelists to communicate with me through raising their hands on, zoom, so I know you have something to say. And I'm going to ask the rest of us to communicate through slack.
09:10:39 So, the, so I'm going to ask the panelists. If you've seen a topic, and this this includes Kate.
09:10:48 If you've seen a topic.
09:10:52 Raised in the slack that you'd like to talk about.
09:10:57 please raise your hand.
09:11:00 And I'll have you talk about it.
09:11:09 Are we all their panelists.
09:11:16 Well, then I'll ask the audience.
09:11:22 Um,
09:11:22 What What questions do you have.
09:11:28 Let's see.
09:11:28 A young.
09:11:31 Young. Yes, um, first of all, cake, this is a greeting up, I have my camera in a weird way, nevermind. I'm going to close my camera. So, this is a really great time I really enjoying it.
09:11:42 I have her questions about your 2012 work where it you say that you find six galaxies with inflows a most of them with high inclination and goes, I think that's really interesting because I always have this image in mind that when you see a galaxy that
09:11:59 is mostly agile, then you see through everything with the this kind of interface basically that you find a star in the desk.
09:12:17 interface. Right. So I was wondering, does that does hate me to face, give you any signals that could result in Russia of this, or could be confused with info.
09:12:32 Does that make sense.
09:12:36 Um, I guess I'm not totally clear on the geometry or you're thinking of.
09:12:44 Oh, you mean if it's a mostly edge on but not exactly at john then you have exactly long view through the disk. Yeah.
09:12:53 Right. And so, maybe if you have like a lagging extra planar layer or something like that that could induce a significant redshift.
09:13:05 I'm not sure if that will result either blue shifted on Russia, so I was wondering if you have tried to do this modeling and see if that's it knows who give you one direction or the other direction.
09:13:17 Yeah.
09:13:18 So I think if I recall correctly and others, you know if others have thought about this I did think about extra planar layers have been inspired by your paper.
09:13:32 And I believe what would happen is, there would be half of the galaxy.
09:13:40 If you have a lagging extra plane earlier you would detect red shifts towards half of the galaxy, and then blue steps towards each other.
09:13:52 And the magnitude of the redshift might end up being larger than that of the blue chefs and this. This is more extreme, the more edge on the Galaxy is.
09:14:04 So, you could induce, you know, read shifted absorption like signal.
09:14:12 But I think it would only be over half of the galaxy.
09:14:16 And so, since.
09:14:28 In that work, our spectroscopy was integrated so it was just, you know, it's dominated by the light towards the center of the galaxies.
09:14:31 And we're detecting and we're only going to check the inflow in those systems if it covers most of the disk, then I think that that like the lagging layer model, can't quite do it just makes sense to me when you mentioned it's an integrated life.
09:14:50 So, yes, I think I wasn't missing that I thought, it is very small pencil being through one particular chunk of the disk, in which case you could get it either second Oh, yeah.
09:15:01 Yeah, so these galaxies are really far away, you know, they're only an arc second across or so so we can only collect all of their light at once.
09:15:12 Thank you.
09:15:14 Panelists club Andre has a hand up.
09:15:19 Hey, This is actually a question for us PKK, that's okay.
09:15:23 So great.
09:15:26 The first part you mentioned evidence for a kitten gas in the form of what I may call low metallic city spots on two galaxies.
09:15:36 And in the last part of your talk, you mentioned evidence for inflows from get shifted spots. So the question is to these corresponds patiently.
09:15:49 That's a great question. I have no idea, but that would be really interesting to look at. Can you remind me what the data, and both studies from manga such as in principle, it would be straightforward to check.
09:16:06 Totally Yes, same galaxies. So that, that'd be great idea.
09:16:13 Check it's good to me that the frequencies you quoted seems similar 10%.
09:16:23 So, so one of the questions that jumped out on the slack for me was still Nelson's asking what is the future for complex absorption profile modeling, when we should always assume a mix of one inflow to outflow three rotating disk and for admission in
09:16:39 filling.
09:16:43 Anybody, is anybody. Dare to tackle that one.
09:16:50 Welcome to others.
09:16:57 Pulling out there.
09:16:59 I don't think I would dare to start to Rebecca this one.
09:17:02 I mean it's just,
09:17:06 yeah, just too complex for us right, I guess, the general question is the nature of what we can do observational Lee is quite a bit different from what people are capable of modeling.
09:17:24 So I think we're all trying to figure out how do we make, cut better contact between what it's possible to observe and what it is possible to model.
09:17:37 If yeah so also ask Claude Andre you know if if you could ask the observers to do something.
09:17:47 What would be your dream thing for them to be able to observe.
09:17:56 Me, make sure I'm going to send you a question. So the dream thing about the depths of us who. Right, right. So, we want to understand how that happens.
09:18:08 And if we, yeah.
09:18:13 We have seen the talk, told us a lot about what it's possible to observe right now.
09:18:18 And I guess I'm wondering you know if you had, knowing what you see in simulations and influence simulations, what would be the ideal observation to be able to make that I just wanted to clarify, is this connected to the last question about the large
09:18:35 number of components and the observation was the sentiment and they put that question.
09:18:40 it's it's an optimistic way of phrasing Dylan's question.
09:18:47 What is the ideal thing.
09:18:52 I'm not sure what the ideal thing is but one thing we haven't heard, too much about this how to detect inflows and the hot gas which I think can be can be quite an important I think it could even be dominant.
09:19:14 In, not only in massive elliptical, and some Elster just galaxies.
09:19:19 In fact, in our fire simulations, we have a recent paper led by Jonathan stone in which we calculate the emergence of hot halos and particular hot gas and the in the CGM with the formation of large galactic this, but we haven't quantified is when these
09:19:47 disk emerged what is the fraction of the total Akita gas mask is called versus hot. So I'm not sure what the answer is. but I think it is plausibly plausibly dominated by podcasts occasion, and I would think it would be great if we could have better observational
09:20:00 science on cooling flows and podcasts on two galaxies.
09:20:06 And just for one I totally agree with you on that.
09:20:12 Such.
09:20:12 Hi. First of all, keep that was a great talk, and in that same spirit.
09:20:17 From what Kate showed and what Dylan is asking, I think we know very little what we're looking for.
09:20:25 So, there have been different aspects to it as Kate mentioned, there is a mentalist city component, clearly very low metal as it is in flow probably certainly velocity is probably the best indicator something coming in but you could have higher Melissa
09:20:42 guess. So, at least as far as I see we have to sort of, specially for absorption line, and that the using a background Quasar I think the, in my opinion, although it's very hard.
09:20:56 I think it is will be the easiest thing is to sort of break down, different aspects of it like using, maybe along the disc where you feel like the rotational component is going to be the maximum or then have a sample, which is vertically.
09:21:14 So, just to break down Dylan's question. I think the one thing that it has been very hard to do and hopefully in the future we can have very large samples.
09:21:27 The idea would be to just break down samples into these components which would have minimal contribution from one aspect or the other. and to do so I think what would really help is for observers to know what is expected.
09:21:45 And I know that the whole lot of things going on and certainly it's not easy to disentangle in a simulation.
09:21:53 But if we can identify a sample of galaxies maybe a quiescent galaxy or or gas Rich h1 galaxy without a whole lot of star formation.
09:22:13 Some, some of those predictions might really help us identify samples that can produce one aspect of it. And then finally everything put together can probably tell us rotation inflow outflow and everything else.
09:22:28 But, yeah, so we don't really have a sample to do so and right now we're struggling to fit everything to one side line to one galaxy which probably is very hard but that's the best we can do.
09:22:50 I was about to say center Filippo has a hand up.
09:22:51 Hello. Thank you very much for the very nice Stoke it, I was.
09:22:58 I mean it. I liked the story also very much at the beginning I didn't know where, where what you were going to tell us at the end and then fortunately at the end, you, you, you said everybody's right.
09:23:12 So, I want to add to this and say that, given the time on the side of the influence so so strongly, but I actually am I perfectly agree that there's three is going to be in flow also along the along the disc in the outer path, because we see lots of gas
09:23:34 in the, in the out of these galaxies and that gas s come from inflow so. So, what I was trying to say and what I think, should concern us is where does the gas that is going to form stars in the galaxies, come from, so that that is the main question,
09:23:54 and and and and if you have gas coming vertically it onto the disk, the gas is already there, and that would certainly form stacks and unless it gets executive again.
09:24:06 If the gas comes into the out of band.
09:24:09 Then, it has to get to the same that before for me starts and that's the process that I'm not sure, as the worst thing.
09:24:18 We see occurring at least with the efficiency, that is needed, but given, going back to the question was asked before and the discussion right the two things to say.
09:24:29 So when you see when we look in the mission.
09:24:33 Like, Kate was showing the planar gas that we can lead, really.
09:24:40 More than everything because then we can model.
09:24:41 We can add kinematic models so dynamic models in ways that are all the components, all the, the velocities together and we do see these general flows that I think is very general that galaxies show as a general flow going into this, but also with absorption.
09:25:02 And, and this is something that I started to do a little bit in the last period, I think, I think there is lots of potential with this very large sum is to put together galaxies and work, statistically, at.
09:25:19 And to some extent, is extremely difficult. And we all know to understand what's going on from a line of sight. But, but there are thousands now line of sight, so let's try to do, to work, to work at models, statistically, that case that basically interpret
09:25:39 these observations because I think there is lots of information. I mean, many people have done it already, but, but I think that's the way to, to, to approach the.
09:25:52 Yeah, they have surgeon.
09:25:56 So I don't have a question I was just, yeah, okay.
09:26:01 I check with Kim has a hand up.
09:26:04 Yes. Oh, since you asked about some theoretical or the theorist expectation from the observation about the inflow and kind of the things that I learned from my simulations.
09:26:25 Although it, because it's a local simulation is always have some limitation, but what I learned is basically the this.
09:26:34 When we have this inflow dominated pays.
09:26:39 That's always come with some kind of the deficit of the star formation basically so there since we are We better when we can't have the feedback, then you can actually kind of dominate by the inflow so nice.
09:27:00 So the and then the large scale inflow.
09:27:04 And this is about the fountain flow agreement in flow, so that if we kind of proved the guests inflow near the desk, and we can basically measure both inflow and star formation rate with the kind of the short term instantaneous defamation ray tracer not
09:27:26 instantaneous but it was with us on short time scary.
09:27:30 Like, HR pa type of tracer.
09:27:34 And if you have some specially the job observation and correlate that whether if those are implement when you have inflow if those are kind of the come with the lowest activation rate fixers Bexar then I think mostly we can say it's more about fountain
09:27:56 driven in flow, I think. And when, When because this.
09:28:03 When star formation has shut off.
09:28:08 Then there are no kind of the hot gas is not really created by the super feedback that means. Now the kind of that is tentatively for Kevin type temperature guests are feeling the volume and falling back so that's what is seen in my simulation, usually.
09:28:29 I'm not sure whether this really valid, even in the global simulation, but I think it's generally have, I think, I may expect more larger covering fraction of the inflow, when it is dominating.
09:28:49 So, I see Greg is a hand up, and there's something I wanted to, if you can hold on to that hat and
09:29:03 There's a theme that I kind of has seen emerging in, in what people have been asking on slack. And if I, if I can bundle it into an idea.
09:29:13 It's a we measure it we can measure we measure inflows and outflows instead of as we tend to talk about what's going on in terms inflows and outflows, but from a galaxy evolution perspective, it's important to be distinguished from circulation and fresh
09:29:29 and flow.
09:29:31 Right. So there's some net, there has to be some net and flow for galaxy to continue to thrive.
09:29:38 And a lot of what the significance of what the galaxy does is circulating which creates both inflow and outflow but doesn't lead to mass, you know, long term mass ejection.
09:29:48 And so the question then is, how do we distinguish these things.
09:30:04 And among the suggestions and their people on the panel who have thought about this.
09:29:58 There is using medalist it as an indicator of what is circulating, and what is fresh.
09:30:05 And I think there's emerging appreciation that angular momentum is also an indicator of what can be fresh, and what is circulating. So, what are your thoughts about how we distinguish between circulation and fresh supply.
09:30:33 where if it's fresh supply you do expect that the Middle East is going to grow now.
09:30:40 Okay.
09:30:43 Yes.
09:30:56 So, in hell we don't know go ahead please continue. Sorry, and we do find, you know when we study low management system, which over dance region in the universe that was the key when we find a lemonade stand we'll find a galaxy, yet.
09:31:01 What we find is that you have lots of these very normal tennis together.
09:31:08 And when I'm saying low it's one person, sort of attempts to less at lower chipped.
09:31:14 And that's basically the same method is to ensure that you found it, how Richie but in this system.
09:31:23 So, by means but you have a lot of these gals which is around galaxy very low maintenance director has not been
09:31:31 polluted by recent star formation.
09:31:36 And so we, you know, what these guys is doing yes we don't know if it's actually throwing, but I don't think we can argue that it's not flowing.
09:31:47 Because we mentality so low.
09:31:50 So, as you know, maybe in another question how do you get in the conference about, you know, Once we use of mentality.
09:31:59 And I think there is these still useful for maternity, because when we, you know, when we talk about 10% sort of meta Justina higher.
09:32:09 That's a think enough and then best once we finally know Miss Julia to the mid care, Adobe he sees in typically about 10% sooner methods to the higher margin stream is about death metal is actually boys Sean shown that you you know these type of made
09:32:29 of metal history, you can just get them by reciting the gas.
09:32:35 history, you can just get them by reciting the gals. You know galactic font and models, and we have over more than a long for a long time. Interesting complex see people were hearing that was like pristine a creation on the table.
09:32:49 I would argue that's purely 10% certain methods she's not pristine.
09:32:53 But when you go down to one person said I made me cry when that when I still ask a question you know what this guy what this guy is doing on galaxies.
09:33:06 And all we do.
09:33:08 Do a center study at higher redshift and we find, you know, joke on one kilometer, or even lower than that.
09:33:16 In these pretty Ilex running from density absorbers.
09:33:21 And in my opinion that's, you know, when you look at, at least some of the diagnostic that the simulation have been arguing for nice.
09:33:38 It must be it must be pretty high I try and find density. And it has to be predominantly seniors.
09:33:42 So yes we we can't show with the observation yet. That is gathering is actually employing onto a galaxy but it's our own galaxy so what he's doing. From the best.
09:33:56 So the action alone. I do not know.
09:33:58 But there is quite a large fraction of it. So,
09:34:04 how do we go to the next step. I'm not sure but I think we will rely on more and more companies and we the simulation and I'm going to prioritize. We have a lot of hands up, and I'm going to prioritize panelist hands.
09:34:20 Cloud Andre.
09:34:22 Yes, I just wanted to add a technical perspective to what Nicholas sent, and. And I think what I'm going to say, large is consistent with what he stated, so Zac Efron has done particular checking analysis of simulation.
09:34:40 analysis you know how the unambiguously whether the gases falling and for the first time, or what it's been another galaxy before and it's a cycling.
09:34:53 And what is shown in the simulation is that very limited the city of other 1% solar can tell you with pretty high confidence that the gas is funding and for the first time.
09:35:06 But there is a pretty wide range of ambiguous multiplicity at them admit that the city is about the 10%.
09:35:18 For example, where the gas can either be falling into the galaxy for the first time, or the cycling and the way that it can have this kind of at me that Medallia city but be falling in to the central galaxy for the first time is because the volume of
09:35:34 Hello can have been previously enrich with metals and then the gas is falling from the last guest structure for the first time, but it's sweet subs and mixes with some metals.
09:35:45 On the way to the central so Velma density in the simulation is a very good predictor that the gas is that you think for the first time, but a lot of the gas is that intimidate, that is, these were the methods city alone does not unambiguously tell you
09:36:02 whether it's funny. Okay.
09:36:04 Sanchez hand up and I just want to plan to see if no one has to answer this but have people looked at all for medalists at the angular momentum correlations, and whether they could be exploited so I'll put that out there and then as such, what, what her
09:36:20 questions. I just have a comment I want to be very quick because they're people only thing related to the circulation process pressure inflow idea.
09:36:32 Clearly, the two things that you mentioned Melissa D and angular momentum are very very good tracers, but statistically, one of the results from cos gas is that the halos of 800 galaxies are rich in gas and it's more strongly correlated to each one of
09:36:50 mass than star formation so will we think that this could be fresh gas because circulation would probably be enhanced with a star formation rate, another result which is not out but it's in submission is that the each one rich galaxies are strong blood
09:37:16 correlated alignment off by absorbers, so these are absorbers were medalists it cannot be measured column density of 13 and 14, per centimeter cube. So, in log scale.
09:37:19 So, essentially, then emission line star forming galaxies. So in some sense would be a broad observation although we cannot say this particular absorber is an inflow versus that.
09:37:34 But overall, this the sense that the h1 rich galaxies are surrounded by these bubbles of gaseous, you know, in the inter galactic medium of 212, mega person away, which is clearly outside their very own radius.
09:37:49 So, essentially, I feel like with all these independent measurements. We do have a sense that there is a bit of fresh equation going on, although we don't know exactly which absorber is placing fresh equation.
09:38:08 Okay, now I've made Greg wait long enough, but Rob male and young had raised their hands during this discussion so we'll have to ask and then we'll return to those other hands, please.
09:38:19 Great.
09:38:22 Well, I see. Maybe what instead of asking my original question. I'll just say,
09:38:30 The,
09:38:33 the, so I just wanted to agree with what Andre said, which is that it's actually quite challenging to distinguish between, you know influence and output guest particular on metal to see alone I actually was thinking very much along the lines of, tried
09:38:57 look at correlations in angular momentum and middle of the city as, as, as you suggested mark. Any particular cosmological simulations you know tend to show that the influence occurring preferentially alone the disc playing with this, and with with high
09:39:07 anger momentum and.
09:39:10 And then the final thing I wanted to point is that point out is that, of course, is an obvious point which is that material, you know, which is undergoing some sort of research evaluation is typically not found very far from the desk so employing gas
09:39:39 large, radio, which of course is observation Lee challenging, but it is a good sign that that's not been researched and actually let me just squeezing my original question which is, so the the observers have.
09:39:46 I think from, first of all, Kate, beautiful talk.
09:39:49 There's been a lot of work Mary Putman few others, many others have looked at dumb, the inflow rates, the Milky Way in particular but other galaxies as well.
09:40:01 But in terms of mass but I'm interested if there's.
09:40:06 What's the prospects for doing it on a larger scale for the angular momentum in flow rate, because we of course disks we think are still being built up from the outside from the inside out.
09:40:17 And so, the expectation is that the info and gas, especially if its pristine has more into the moment.
09:40:27 So you're asking for Kate to comment right.
09:40:35 Greg, well, gosh, I mean, in the Milky Way. People should correct me on this but in the Milky Way, I think, you know, people are Filippo for instance has demonstrated that the H VCs can be explained by by a fountain model.
09:40:56 So I don't know that we have examples in the Milky Way of of complexes that we know to be fresh info Unless Unless we would consider it a module on extreme to be fresh and flow.
09:41:14 And so that, I mean, we, we must have great measurements of that angular momentum.
09:41:23 But if we already know it's fresh and slow I'm not sure what we're learning from that.
09:41:33 When it comes to other galaxies.
09:41:37 I don't know i mean i think crystal Martin's work maybe she can comment on you know she's measured put constraints on the angular motions of, or as a musical emotions of gas or in the halos of galaxies.
09:41:57 Perhaps there are prospects for also measuring gases metal a city, maybe
09:42:07 I could just say real quick. The hard part is getting the hydrogen column.
09:42:12 Yeah. Indeed.
09:42:22 All right, rebels had his hand up for quite a while. So, what will happen.
09:42:20 Cool. Yeah. So yeah, going back to sort of the the metals and angular momentum.
09:42:27 QUESTION So we looked at both of these things actually in Charlotte Christensen zooms, a few years ago which are, you know, similar to the Niihau simulations and it'll their input physics.
09:42:38 So, I think, you know, in terms of the metals, I think, what cloud Andre said and in what others have said is, is largely reproduced in those in terms of the angular momentum maybe I'll just mention a result that might be a little bit surprising to people
09:42:52 so when we track the particles. We found that the particles that were rejected were reacquainted with an angular momentum that were that's typically significantly higher than than what they left with.
09:43:08 So factor of typically two and a half to three times higher.
09:43:12 So that's when they rejoin the galaxy.
09:43:15 So in point of fact, it's not totally up. In fact, I would say it's just the opposite, that the recruiting material is actually higher angular momentum than just sort of regular inflow material if you think the influencing material basically is, you know,
09:43:32 responsible for the angular momentum of the desk. So, so that's sort of, you know, we didn't do a direct comparison to the in flowing angular momentum so maybe you should, we should have done that but I'm just saying that like, what happens at the desk
09:43:47 is that, or what happens to these outflows is that they go out and to basically get worked up.
09:43:53 As you know by the by the halo gas they get sort of swept in, and they pick up a lot of angular momentum out there. So, so it's a little bit more complicated, so I don't know I think it's a really interesting idea to look at this correlation between Angular
09:44:06 momentum and medalists at and see if there are regions of parameter space that that would be identifiable for that but but yeah the angular momentum story of galaxies is actually pretty complicated, and of course it's part of the reason why you know we
09:44:21 we can now produce things like bolus dis galaxies for, you know, in the original ways we couldn't, right, it's this this is exactly the process that does it.
09:44:30 So, anyway, I just wanted to mention that.
09:44:34 Okay, thanks. youngest ever had it for quite a while.
09:44:38 Thank you. Um, so, I have two questions. The first question I asked during the slack already, which is how do we actually measure the angular momentum and observation, because if you look at a milky way observers, or an H wallet, we only get a line of
09:45:04 velocity we don't get a chance verse, velocity, in which case you don't really have angular momentum estimate right so it doesn't involve any model assumptions.
09:45:03 So that's my first question. The second question is going back to your earlier question in terms of in terms of how to distinguish between inflow and outflow whether we can use metal the state and get a momentum.
09:45:20 The third parameter, I'm thinking is perhaps no line with our dark chocolate with. So, this is a question for in the theorists, especially for those people working on turbulent mixing interface or understanding how cold gas mixing with hockey is.
09:45:35 So, do you see a change of doctor with a line broadening when you study that evolution co clouds mixing with hot gas and eventually coming back to that this is there a change from smaller p value to larger be value or to mix it up everything, and that's
09:45:58 that's how as ending signatures of influence outflow.
09:45:57 So that's my two questions. Thank you.
09:46:00 directly to the theorists on the panel
09:46:08 thing the first question. Krista wanted to comment on the algorithm I'm not sure, real quickly in terms of measuring angular momentum, it's a derived quantity, right in the sight line we measure line of sight velocity and impact parameter.
09:46:25 We've argued that if you know the orientation of the galaxy the position angle the quasar the inclination of the desk, and which side of the desk is closer to you, then you can make an assumption, you can say, if the absorption along the line of sight
09:46:41 is in the plane of that thing this, then this would be the radius in the display, and this would be the velocity in the display, then you have a specific angular momentum.
09:46:54 You can do the same thing with a thick disk model, and a vertical velocity gradient of oh there's a few more parameters involved in. So it's very much a derived quantity.
09:47:08 Okay.
09:47:11 Do any theorists in the panel want to respond to the second part of the angst question.
09:47:26 You can always raise your hand and respond at a later time, or this could be a pet project for some theorists to take a quick look at the data, I'll be really interested to know what's going on.
09:47:29 Yes pet project for sale. There you go. Um, Yeah, okay, Filippo had a hand up.
09:47:35 Yes, thanks. So this was a reaction to Greg's question and also what young just said so. So, I agree that in the Milky Way is almost impossible to measure the angular momentum, without a model, you need a model of your of their own.
09:47:57 Extra plane and material to understand what the angular momentum of the accreting gas can be. So, so, in, in, in, in the Phantom model where there is the fact that he gives the condensation.
09:48:11 The pristine gas athletes at the radiance that is not so small, is actually quite large is around the peak of their traditional rate is around eight gigabytes it from the same thing.
09:48:39 And because angular momentum is RV. Actually, the disk through the circulation is gaining anger moment. So this is increasing. Through this type of activation, I don't know.
09:48:41 I don't know if anybody has made the modal of of the Milky Way.
09:48:48 I mean, layer is the plane and layer from other types of operation so but then in the Falcon context, the inside out is preserved the angular momentum of the accreting material is larger than the average angular momentum of the disk, which is important,
09:49:10 and I yeah, I'll get to near in a second. I want to be up but then Oppenheimer in slack is saying a lot of simulations ego especially show a lot of manual men in the hot phase.
09:49:22 In fact, there may be more angular mental hot face in the cool phase. And in that context, if people aren't aware, the angular one of the hot phase around the Milky Way has been detected through absorption line studies by Joel Bregman and and his group,
09:49:38 by looking at absorption lines in different directions and try to model velocity chefs, they're able to detect that the Milky Way's hot Halo is rotating it constraints, we are quite model dependent but there is rotation of the hot face near.
09:49:58 I thanks very much.
09:50:00 So I put this question in the slack as well and I guess there was a bit of discussion around it but it's something that I'm a little confused about is the.
09:50:09 So when we speak about accretion of cool gas from the intergalactic meeting fresh accretion which has high angular momentum and is accreting along the major axis, the famous cartoon from the Tumlinson people's work model that always comes to mind is of
09:50:28 those accretion streams. However, at least the, like, from the theory perspective we don't really expect these so called cold stream equation model to be present except for the most massive galaxies at any given you know time at redshift one only galaxies
09:50:43 above you know 10 to 13 solar masses or so is the high angular momentum guests are the largely rotating guests that we're observing. Is that a different mode from the so called thin accretion streams is that just condensation and cooling of high angular
09:51:00 momentum, creating gas which might be creating more ice topically on large scales, does it connect intergalactic filaments to this the same phenomenon or a different phenomenon
09:51:14 called Andre, you have insights here.
09:51:22 I guess my. Not sure this is an insight, but I would echo what Neo was saying, which is that the card Tumlinson cartoon does not match a milky way like zero galaxy in the simulations, and this is another business simulations the disc.
09:51:43 Like no keyword I get X is 00.
09:51:47 X is at 00. The camera is surrounded by hot gas with perhaps clumps of cool guests falling and once in a while but they don't have these Long live 10 streams spiraling in, so that that picture with the as the ascent in the simulations maga presented to
09:52:03 have a massive galaxy yet, perhaps catch it for two.
09:52:08 So perhaps some people to keep in mind when they are inspired by the cartoon,
09:52:22 maybe be a Jaffa other people on the interview article can tell us what kind of galaxy this Khatoon was supposed to.
09:52:30 I mean, always meant as a cartoon and in fact we've said amongst ourselves but it's almost definitely wrong, and we're looking forward to people discussing all the ways in which it's wrong so this is perfect.
09:52:44 Okay.
09:52:52 Yeah.
09:52:47 Nicholas on this topic.
09:52:56 And the other thing is I thought from the simulation i wish i decoded the transition was more word shift. 122 12.
09:53:10 So that's one thing.
09:53:23 You could have those streams and transition is going to vary depends on the multiplicity of the AGM, but it's not inconceivable that there are situations where this this picture is clickable and Richard one or a zero is a different story.
09:53:31 Maybe.
09:53:34 While people have mentioned higher Richard stuff at Tim Heckman had a kind of interesting comment in the slack if you compare the outward work that refers to the winter, they were force of gravity then you can define a critical calm density but which
09:53:47 gravity wins on the radio scale the line and break galaxy this critical common one is about to the 22.
09:53:53 on the radio scale the line and break galaxy this critical common one is about to the 22. And the point is that there could be stuff that's falling like bricks that is relatively invisible because it's so optically thick.
09:54:04 Does that does that cause concern or or is this something we have hope of measuring could this is a realistic picture for what's going on and Hi, Richard.
09:54:20 Mark just to comment I had some exchanges with x as well Slack channel but I just want to emphasize this is talking about gas on galaxy scales not the CGM.
09:54:27 Okay.
09:54:29 So, it is mainly just that you know Gravity Falls like one of our our and I said terminal potential whereas the ram pressure is dropping like one of our r squared so if you get far out.
09:54:38 gravity has any time but this this this was really just an attempt to explain why we have, you know, hundreds and hundreds of linemen break galaxy spectra and almost always see outflows, there could be invisible stuff falling in that's just optically
09:54:54 thick to dust.
09:54:56 Right, I was thinking of this in the context of the difficulty of locating called streams.
09:55:01 But, such as a hand up.
09:55:06 Oh, yeah, I just wanted to mention one observation I want to tag yes and around one if they're here and in case.
09:55:16 In general, what we find in in CGM is that absorbers are very close to the systemic we don't see like hold on to floating stuff in velocities allowed by the burial theorem also, and especially the ones that we have a twin masses and profiles, so we can
09:55:32 pretty much see the entire rotating this in velocity, almost 90% of the CGM absorbers have velocities within the rotating disk, what is allowed within the rotating this.
09:55:45 So, so I think that's something.
09:55:48 People can think about in theory, when they're modeling Angular, of course I don't have Angular philosophies, but the fact that even if its orientation, we have a bunch of galaxies the fact that we do not find absorbers with velocity is higher than the
09:56:04 rotational velocity of the galaxy in the nearby universe is kind of interesting.
09:56:26 And I'm sure just might add something in, and for Hey, cos halos around one might add something for cos doors. I'm not sure if he's around. I think that's a great point songs, and I've always been really fascinated by the kind of sub variable, you know
09:56:28 velocities of the absorbers that you see in the circle galactic media amount to, you know, 150 kilo parsecs. I think that there's something very interesting there that it's it's it's not 100% clear to me that we know the answer I do like the picture that
09:56:43 Matt McQueen and I presented in 2018, that paper, if anybody wants to go look at it, of this cooling inflow.
09:56:54 But I'm sure there are others that can
09:57:00 Solon a slash one of them will go. Okay.
09:57:22 Go Sorry, I was just gonna say I always in Tripoli, this is probably some sort of drag that you just things don't reach a terminal velocity they're condensing out of something and they don't last long enough to actually be accelerated up to, you know,
09:57:15 freefall basically. Yeah. And actually that's part of the picture I think that Matt and I talked about is that content of continual regeneration of cool material.
09:57:29 And I will suggest, it can also be analyzed in terms of gravity waves but I won't go any further on that here.
09:57:38 I'm a point out crystal, Martin suggests in the Slack channel we need a halo 21 schematics channel where you can collect cartoons for inflow phases. In fact, it would be very illuminating to have every meeting participants submit a cartoon, so you can
09:58:00 see what's actually in people's heads would be amazing visualization, perhaps, I'm talking about something different. I'm asked in meetings, one of my favorite things it asked in Blackboard meetings is to watch theorists draw graphs of data, it because
09:58:08 it's not the data, it's, it's what they think the data is and it's very illuminating to see what people think the data is when they draw it on a blackboard.
09:58:17 It may be already also illuminating to see what people have in their heads if he has to take a white sheet of paper and draw a cartoon of the CGM like what it actually looks like.
09:58:28 I'm not sure that qualifies as a visualization, but it can be psychologically very interesting to see what's actually in that person's head. No wonder I don't understand what they're talking about because that's what's in their head when they think of
09:58:40 the CGM that cartoon.
09:58:45 Maybe the organizers can think about this but a gallery of cartoon CGM might be therapeutic at very least.
09:58:56 We're, we have only a couple minutes left in there there are no hands up immediately.
09:59:05 And so maybe this is a good place to point ahead toward the rest of the week.
09:59:11 Interestingly, a number of the things that have come up in this discussion.
09:59:15 There are going to be tutorials on them tomorrow.
09:59:19 Near Amanda car will be telling us about the physics of cold streams, Jonathan stern will be telling us about the physics of hot halos and cooling falls within them and I'm sure, having read Jonathan's recent papers.
09:59:32 We're going to find out what happens when they're these cooling flows have some angular momentum. And how is that related to the disk, and the formation of cool gas.
09:59:44 We, we think, well, there could be a third tutorial, we're still I'm still trying to figure this out.
09:59:53 But there will be at least two tutorials tomorrow.
09:59:55 And then once you're all up to speed on that physics, we will have do some courage give a more simulation oriented talk on how does gas get into galaxies.
10:00:06 So, if you have if you if you just need more science today. Remember that there is an after party at 1pm Pacific on quenching.
10:00:18 I've asked them since I personally can attend. I asked them to tape it and put the video up so if you can't make it.
10:00:27 There will be a video. I am promised.
10:00:38 Today the organizers have something else to say at this time. If not, I want to thank our speaker and our panelists for a really really interesting discussion.
10:00:56 And I appreciate everybody's eagerness to participate and share their views and to be clear, and pointed about it so. So thank you. And we'll see you again tomorrow.
10:01:00 If not, at the after party.