09:05:09 All right. Um, Well, I imagine all of the panelists can see that the questions that have been put into the Slack channel.
09:05:23 I'm going to try my best to be a pretty passive moderator and ask our panelists to look at the kinds of questions people are putting their and decide what they'd like to take on.
09:05:35 So, yes, our panelists, by the way, are Megan, a reef bubble. Ben Oppenheimer and Nick Talia.
09:05:45 And I, I guess. I want to make sure we hear from Nick Natalia, in particular because the sZ observations are probably going to make the most progress on these questions of how many baryons associated with groups, and where are they probably most progress
09:06:05 in the next several years is going to come from their effect there already is in progress. So, all.
09:06:14 If someone doesn't jump in from the panel. I'll toss a question out to you.
09:06:21 I'll jump in, I'll take Marcus's question, where do you put the boundary between groups and clusters.
09:06:27 I could show you a plot but I'm pretty sure this is a question that will depend on who's answering it.
09:06:36 My.
09:06:38 I personally put it around. One kV in temperature, and my reason for that would be that if you look at the LT diagram for example.
09:06:48 That's roughly where the LT changes slow.
09:06:52 It goes from, you know, being close to L going as t squared to steepening up to roughly about l going SD to the three points something or four. And the reason for that is that this is also the temperature where
09:07:11 cooling emission lines become important.
09:07:15 If you look at dynamics. It's also roughly the place where the barrier infraction starts to drop the block that Megan had shown you that, you know, in one of our papers in Liang at all.
09:07:29 We had blood barrier infraction that included stars. Guests fraction, things like that, you see a much more precipitous change in these in this fractions, at around that mass scale or temperature scale.
09:07:47 So, that that's my answer.
09:07:58 Okay.
09:07:58 Are there answers the differ.
09:07:58 Can I just jump in with a question related to that, I, I always had that picture that that reaches mentioned in my, in my mind, but I didn't see that in the plot that Megan showed that did that Benko ways and now debated.
09:08:18 Um, I guess the moderator can can weigh in on that.
09:08:22 Um, so the result that I read quoted were there seems to be a distinct steepening of the LT relation, at around a Ke Ke VI, a significant amount of that happens to do has to do with how the radius out to which was measured depends on Halo mass.
09:08:41 So, when you're certainly in groups. A number of the earlier measurements of extra luminosity in groups, they go out to sort of the detection rate is wouldn't go all the way out to our 500 and increasingly as people have been able to measure out to our
09:09:00 The, the results are turning more into the extension of the same relation. And so I'm not going to post. Well, I guess I can put a more elaborate figure into the Slack channel that it's very busy, but it shows.
09:09:20 If you compare things at the same temperature as you keep taking large and larger apertures, you end up accumulating more and more luminosity so I will let the discussion continue and try to dig out that figure and put it in the Slack channel.
09:09:35 So I would respectfully disagree.
09:09:39 And maybe that's the fun part of a discussion, actually.
09:09:46 Yeah, there.
09:10:04 There's a huge problem with groups. Unlike clusters where the surface brightness is is is high, and they are easy to see and easy to measure with groups, there is a problem with surface brightness and there is a huge variability and most of the X ray
09:10:06 selected samples as we heard yesterday, or day before yesterday, sorry.
09:10:12 You know, are picking up a slice of the groups. So, we've been looking at.
09:10:18 Selecting groups in various different ways.
09:10:22 There is a paper published a couple of years ago. Pearson at all. That took the gamma catalog.
09:10:31 And, and then further process that to make sure that these were very aligned groups or at least gravitation. We can argue about what virtualization means but that they, they were genuine gravitationally bound groups, and then we got X ray data for these
09:10:47 things, and you can see that there are bright groups and there are very faint groups. And, you know, if you're looking at the upper envelope of that sample then mark is right.
09:10:58 You see an extension. But if you, if you take into account the scatter and try and fit to the scatter, then you see the same thing that Trevor So way back when, which is a steepening.
09:11:11 We've also been doing the same thing with globes sample which you know Sullivan has been leading. It's a sample of nearby groups. We have exquisite data in multi wavelength, and the same kind of trends start are appearing there so it really depends on
09:11:29 how you define your sample. If you are focusing entirely on an X ray selected sample, you are subject to certain biases.
09:11:39 And those biases will give you the trends that, that, that seem to suggest a continuation.
09:11:47 I would argue that the stack seem to show it's it's rather continuous I mean if you're stacking on large red galaxies and the it like me Anderson analysis on it shows a turn that's below the X ray selected sample which is what you'd expect because the
09:12:03 X ray bias is going to push
09:12:07 X ray luminous groups which I clearly more luminous and other groups.
09:12:13 Above the relationship but but the stacks I think might give a more reliable measure of what the average is and that is it is at least at the scale of one kV, it is consistently below the level of the detections right so, Yeah.
09:12:37 Um, and, uh, the, the issue of scatter is important, you saw for clusters in the Corps there's enormous scatter, whereas out in the outskirts, not, not what some people call the outskirts but outside of say 15% of our 500, the properties are a lot more
09:12:58 regular, but in groups I think they're more dominated by these core processes which gives you this, this bigger range of of
09:13:10 just the central entities on some things are going to be very low density some people will be high density and it's more regulated by the, the astrophysics.
09:13:19 So the only thing I would add to that is, Megan mentioned that selecting on the red galaxies that itself is a selection process. Sure, yeah, and that you know it turns out that the systems that have read that galaxies in their centers are also the ones
09:13:36 that are tend to be X ray bright and have tend to have higher surface brightness in the center. There is a huge variation in the, in the morphology and kinematics of Central galaxies in groups.
09:13:51 Megan, and I and II Lanny Elana is the lead on this has been working on this there's a couple of papers on that have been that came out this year on that subject.
09:14:02 And when you start to look at the diversity of the kinematics, or we're working on the paper on the diversity of morphology, then again you start to recover this large scatter.
09:14:15 And, again, you start to see that, that there there is a huge variation and Alex on the group scale.
09:14:23 You know we have models that can reproduce that kind of steepening, and you know, if, if, Mark allows me to share a screen, I could show you a picture from a paper that had looked at ramiele Simba simulation run, where the results, more or less, capture
09:14:45 that steepening as well so it's not just observational. It's also. You also see it manifesting in simulations, but at the same time, I have.
09:14:55 I'm working with five different models in the simulations, and I can get anything you want.
09:15:02 In those simulations I can get steepening depending on how you model feedback, how you implement.
09:15:08 You know the various sub grid processes. I can get steepening or I don't see any steepening.
09:15:15 So, you know, it is, you know, groups are exciting, in the sense that very little is known about them, and there's a lot to mind here
09:15:31 Or if I'm working on getting you the permissions to end all the panelists to be able to share their screens, so stay tuned.
09:15:37 Okay, I think I do, I think I've just gotten.
09:15:41 Let's see if I can find right what is one of the challenges of groups is the, you have a you know a nice temple locally that you don't have to get too far away before they become really hard to see because, not just because they're low luminosity but
09:15:59 because the redshift takes their extra energies too low energies where it's very, very, very difficult to study, and especially now that with the current instruments losing their, their low energy sensitivity.
09:16:14 It's.
09:16:17 If I shared this, do you see monkey, do you see my Safari screen.
09:16:23 This one, I see a PDF, something right yeah you see a PDF with blogs, like this blog right here. Yeah.
09:16:31 Okay, okay, okay. So here's the LT diagram that I wanted to show you that you know shows that on the cluster scale you, you have the standard relationship.
09:16:42 If you follow that lt diagram down the upper envelope of the group is essentially an extension.
09:16:50 But the scatter is huge. I should mention that these data points here. We were very careful about this our 500, and how what the extent of the radius was in terms of measurements, this is, as I mentioned the other day this is work that john Mulkey and
09:17:07 and Zeb would have had done, way back when, and shown that this was a significant source of of bias and uncertainty. And so when we were compiling data here, we were trying to be very careful in ensuring that that was not the cause of this drop and subsequent
09:17:26 work has been trying to look at exactly what the systems are, for example, out simulations would predict that there are there's there are a lot of systems that have a very low gas fraction, and therefore are intrinsically them and you wouldn't see them
09:17:44 easily. You wouldn't you know they would appear down here you see the models are steepening as well. So this is that this is from the actual it's not, it's a symbol model.
09:17:54 And so you can see that the models get that here. Let me show you very quickly, something else.
09:18:02 And, which will show you what I meant by diversity and how changing or playing with playing with.
09:18:13 Sorry. I don't have the LT diagram easily available.
09:18:17 I, I will go back to the last picture and show you the berry on fractions, because that was something that is directly related to the theme of this. And as you do that, I'm going to ask the other two panelists to be picking out other discussion topics,
09:18:38 while you finish this one. Yeah. So, so here you can see that this is again data that similar to what Megan had shown, where we were showing em baryons over 500, both at 502 hundred.
09:18:54 You can see what the models are predicting, you can see what the observations are showing. These are the trends that, you know, Megan shown the gas fraction trend.
09:19:05 And so you see these things. This is again the black points here, referred to a model, a simulation. This is from December and and what I really wanted to show you in terms of presenting a diversity and and an opportunity for somebody like Nick to come
09:19:21 along and set us straight, is the following.
09:19:26 So, here is the result that we it's you know this is sort of hot off the press, they are still bugs to sort out in the in the in the calculations, but this is from the Romulus suite of simulations, one of the highest resolution simulations done with a
09:19:46 math and dark matter resolution of order 10 to the five, there's a cluster of galaxies, there's a bunch of zoom simulations of intermediate mass.
09:19:57 Rich groups slash or clusters, and a whole bunch of groups. And what you can see here is that there's zero trend in decreasing in terms of very unstructured, there is a trend with the gas.
09:20:10 But there is no change in the very on fraction. So, you know, this, this is a this is a conundrum trying to understand which of these two models and, you know, whether it's the physics, or what and most likely it's the implementation.
09:20:27 And which of the two implementations are more accurately or correctly capturing, things like stellar feedbacks that early times and he and feedbacks that lead times.
09:20:37 Okay.
09:20:38 stars, Nick. Nick and or Ben, what would you like to discuss.
09:20:45 I have a question that I'm formulating.
09:20:50 And I'll put it in the, in the window. I haven't finished it yet, but in the slack chat.
09:21:00 Um, well I mean Nick can give an sZ perspective, one, this gas fraction question.
09:21:07 Well, and certainly.
09:21:10 First I'd like to thank Mark is for opening this can of worms.
09:21:16 Second, take it off my SC hat for a second because I can talk for hours on the SD,
09:21:25 and an optical observer would would argue that you know God groups and clusters are defined by the number of galaxies within the halo right they have this richness, so they may they may argue with the LT relation.
09:21:38 In terms of sZ, we don't necessarily see the break that scene in the LT relation, if you look at results from plank and from act and from SPT or seems at least in stalking analysis, it seems to be self similar are very close to self similar almost all
09:21:53 the way down.
09:21:55 That being said, there is some hints that it may start to break once you get below 10 to the 13 and this is work, led by Colin Hill and and folks had that you pin, as well so goodness Jane and Adam lives.
09:22:09 In terms of the barrier, I I'm tending to move away from sort of integrated quantities Where is a really nice discussion on the, on the X ray call last night that Daniel lead.
09:22:22 Talking about using all the information right So in principle having profiles, really, really helps determine the difference between. So getting back to a risk question whether you know is it the different, different physics models that's producing these,
09:22:36 you know, you know, potentially steeping in the, in the, in the berry on fraction as a function of mass.
09:22:45 We won't really know by having just one number right, there's lots of different physics models that can actually mimic this and that can be seen by you know just the different.
09:22:56 The different results we get from say the the the large cosmological simulations that exist out there, right. I think having full thermodynamic profiles of of these of these galaxies and groups, really goes a long way in helping us determine what what's
09:23:12 going on, physically, what are the physical processes of feedback that really that are really important, the transport of that energy, etc etc and so I, you know, I, I'm hoping at some point to give a longer talk on some some recent results we've had
09:23:29 from act and and showing where we can go in the future as well.
09:23:49 So, so yeah so from from an SEO perspective from a thermal SEO perspective, which is what most people are used to. We don't really see, we don't really see a breakthrough some hints that there could be a break at lower masses, and from a from a newer
09:23:52 Casey perspective we can actually really start to unbiased the trace baryons out to a very, very large radio, radio, radio, radio, in, in all the way down to groups.
09:24:06 So tend to 13 solo ms halos, and we can go even lower if there's larger spectroscopic surveys so there's there's really lots, lots to talk about.
09:24:23 So Ben I see the question typed in is is kind of overlapping somewhat with what we're discussing Do you want to write. Yeah, I definitely wanted to expand and talk to about thermo as se and even kinetic se, and the missing baryons that appear to be missing
09:24:37 from groups and we're talking scales of 10 of the 13.5 Halo mass.
09:24:45 Are they found in these x measurements from Nick and his his group out at, you know, very high radio I like to do for our, it actually might be to do for our 200 even further.
09:25:02 And, you know, discussing this.
09:25:04 It's a measurement of pressure as well as density, it seems like from that.
09:25:12 For the from those results the, the gas is also very hot.
09:25:17 Or, you know has a lot more thermal energy then like simulations like illustrious tng expect so are the two consists consistent with each other with some.
09:25:27 The X ray and the SSSZ
09:25:35 that a question directed at some I mean it's a nickname answer, making to can answer I others can answer as well. So as a discussion point.
09:25:47 I'm going to put up this.
09:25:49 I agree with Nick and I think the question been posed is, is that on. This is a image is a block from the same paper I had shown that LD diagram earlier, which shows the profile of the various infraction, and in different mass Ben so just to just to put
09:26:07 a context to my one kV. It is about. em 500 of about 13.3 or so. So, yeah, I wouldn't have expected there to be had been a break even in the sec at a higher mass scale.
09:26:23 It's when you start pushing down to about 10 to the 13, that it becomes interesting in terms of the breaks, but this is a lot of the barrier infraction you can see that the barium fraction in these particular models.
09:26:37 Do not recover back to Universal value, until about three times are 200. And so that's where I think the SEC has a huge scope in being able to bend down these, these models.
09:26:54 Yeah, I think, you know, the variable radius is not really the thing stop.
09:26:59 Yeah, there's still stuff that's going to be beyond the viewers and come back it's still gravitationally bound and included so that it's not, I think, on the notion of things being pushed out has to be clarified because out means pretty darn far, you
09:27:18 know when it comes to the systems, it's not, it's not like there's a cliff at our 500 beyond which is gone so it's.
09:27:26 Yeah, except that Romulus, for example would predict that nothing is being pushed out beyond our 200. Right, or 500 yes but are 200 know, so I friendly dude is Austin or observational limit and that's right yeah so so conceptually sometimes I think you
09:27:42 know I see people talking about gas being pushed out of galaxies or gas being pushed out of clusters and it's, you know, but that's harder to do than you might think.
09:27:49 When, in the simulations can be very useful in visualizing right in that light. I want to shift the discussion a little bit to a topic that just work put into the slack, I'd be interested to know the current state of hundred equals simulations and clusters,
09:28:06 and particularly SPECT of heating, cooling mechanisms and weather is now sufficient mass resolution to reproduce scaling relations in a self consistent manner.
09:28:14 So in brief, how are simulations with feedback doing in reproducing the scaling relations that are observed.
09:28:22 So it actually again it's going back to the, the choice of the manner in which the feedback is being put in, and also the level to which feedback is capturing physics.
09:28:38 So for example, most of the simulations.
09:28:42 To date, tend to do not have two modes for a GM feedback. They have a single mode, where there is either a thermal dump, or kinetic outflow without distinguishing whether it's a low luminosity Ag and which, in real life would behave like with jets, or
09:29:02 a large, you know, a quasar mode with, with much more of a isotopic wind.
09:29:08 And so trying to do that.
09:29:11 It has been a huge challenge, because in simulations, you are also missing a lot of other processes, or that they are not well captured, things like diffusion of energy for example so you if you put things in a jet, and you do not have these other aspects
09:29:30 captured well that energy will not distribute itself efficiently and you will start to reestablish cooling flows in a tremendous way along the perpendicular direction.
09:29:42 And so, you know, that's an open question, it's still very much work in progress.
09:29:49 I know that people like double breasted Jackie are working on it, my own graduate student is is coming has developed a new model that tends to work a lot better.
09:30:00 And so that's one aspect of the challenge.
09:30:04 The other aspect of the challenges that historically in black, in the simulations.
09:30:10 Because of resolution, black holes were seated in halos only when the halos get above a certain mass.
09:30:18 Right. And then they are pinned to the center of those halos, which means they feed most efficiently, even during mergers, whereas you know in real life, you would expect that when mergers happened black holes will get swung around and will orbit around,
09:30:33 and during that phase will not be able to feed very efficiently.
09:30:39 And so that affects growth of black hole that affects feedback energy input into black holes into the systems into their wider environment. And, you know, Michael Tamil has developed her has been developing this or has been attempting to follow black
09:30:57 holes in the dynamical fashion, where black holes are free range, as he likes to put it, they can move around.
09:31:07 They suffered dynamical friction.
09:31:10 You get very different results. Okay. And so trying to capture that. Let me redirect Yeah, I want to ask, Nick. In particular, my impression from solid work that you've been on is when you implement feedback in a, you know, a 2020 is kind of way, you
09:31:30 actually are more successful at reproducing the scaling relations where you do a pretty good job, then you know all the details about black hole history and you know details of profiles, but the scaling relations aren't too bad.
09:31:44 Is that a correct impression.
09:31:46 Yeah but oftentimes those are also used to tune some of these feedback. So, I mean, the mean, a big example is illustrious right the first illustrious just was, and they pointed this out very right rightfully so, was horrible at predicting the very on
09:32:01 fraction.
09:32:02 They went back and they use that as an input for tuning their models.
09:32:08 And, and then they did better on these integrated quantities. And now we look at illustrious tng and we look at predictions for their density and pressure profiles and now they don't do so well on sort of the profile quantities.
09:32:22 And the same thing could be said for you know Bahamas did a really nice job of, you know, using this additional information to on cluster scales and group scales right to help tune their feedback models, such that they produce the appropriate scanning
09:32:37 relations for clusters.
09:32:38 So, so yeah I mean people are you know simulators will use what they have at their disposal observations to, you know better their simulations I know I'm Ben.
09:32:49 Ben has his hand raised and I know he's got a lot to say on this chance to say, Okay, I'm going to try sharing my.
09:32:56 Do you see that, that, that plot.
09:33:00 We okay yeah so that was well, elephant to justice and next discussion of, you know, just the very infractions inside of, well, MM 200 so not profiles here, but, you know, this is something I'm working on with a refund groups review.
09:33:22 And, yeah, you can see that, you know, you know, the state of cut you know modeling clusters and simulations, you know, all these you know a lot of these like Eagle has a cluster focus in hydrangea that Yannick by he runs but you can see that often they,
09:33:36 you know, if you use the equal prescription, it will get the barrier infractions too high, come and the extra the extra humanized Manassas will be to break.
09:33:47 Like illustrious TTNG tuned their feedback to some group fraction you know group area infraction
09:33:58 yo some group fractions compiled by.
09:34:03 I can't remember actually gonna be me, I think.
09:34:08 And still, if you look at Bahamas, and also Simba, which they have lower barrier infractions at that group scale of flight say 10 to 13.5. And that's interesting and, and what happens then is the x ray luminosity go down, which seemed to be necessary.
09:34:29 And then like that. Those bit you know those barriers that are pushed out from, you know, Nick's work. The Act results.
09:34:38 am I saying, I'ma do right is that the person who said, Who, who published this, is that a lot of those baryons are pushed out to two to four are 200.
09:34:58 And are you appear to have pressure a lot of above tng.
09:34:59 And I'll let Nick, take over from there and talk about that. Hang on, Ben, there's a question in the chat, what's the difference between the lines in the points.
09:35:11 Yes. Okay, I'll share it again.
09:35:15 You know, the points are individual cases the lines are our averages that with, with a one sigma scatter so they're the same it's just like you have smaller small numbers statistics so it's just like a arbitrary kind of choices the same data.
09:35:31 It just individual objects.
09:35:36 I have another thing I you know I look at the questions I'd like to hear about discussing the committee. Joe Birgit asked in the LT relation Why is the suppression of LKT necessarily due to feedback and not because the gas might simply be a non extra
09:36:10 phase. So, how certain are we, that the missing baryons are not just in some non X ray observable phase.
09:36:10 This is a dangerous question, I don't hear anybody speaking up.
09:36:28 We're waiting for Megan to to chime in and then I'm sorry I posted an answer.
09:36:23 I think we do have pretty good.
09:36:26 Can you hear me.
09:36:28 Yes.
09:36:29 I think we have pretty good census of data of the baryons in clusters Anyway, um, because we can, we can go and search out the stars and even entire cluster lights been pretty well detected actually it's a nuisance background for, for people who are trying
09:36:47 to study cluster members, you know.
09:36:55 And so, in your cluster light cold gas in clusters there's a pretty, pretty solid limits now from Herschel and on them.
09:37:08 And so I think are very on census and clusters is pretty good.
09:37:14 I guess is the short answer. So I think my concern. My concern was at lower masses, when you go down in groups. Oh yeah, so I think they're the stellar census in particular is still incomplete, and it's it's a mess there miss your harder systems to deal
09:37:32 with the backgrounds of programs. It is, it is tough sledding to get stellar senses of groups if you can get a like an XML, X ray observation, it's nice and wide field and, you know, ironically that that's that's sort of easy to see but but actually you
09:37:52 know getting a star budget is hard, I think, So you think it's in stars and not gas.
09:37:57 But that's my guess this one guess that there's more stars.
09:38:03 Not saying something I'm cool gas UV Trace Gas. I don't think it's there.
09:38:09 I mean there's, you know, you know, john stock he's groups.
09:38:14 You know, you're involved in that.
09:38:18 You know, I'm looking at cost halos passive galaxies challenge, allergies, you know, you can't have a significant barrier infraction, you know, in the less than you know 10 to five and under Calvin gas so you've kind of running out of things where you
09:38:35 could put put those baryons, so that's interesting.
09:38:40 Again, going back to the tsunami of Zelda effect. Those Barrett missing baryons may be very far away.
09:38:48 Yeah, it also can see is it's an unbiased tracer of free electrons.
09:38:56 Right, as long as you if you're doing a, at least in the estimators we use, where it's just proportional to the velocity dispersion, which we can know cause logically.
09:39:07 The rest is just the very own fraction, and another, I mean we've heard about fo our bes yesterday effort, these are also a great unbias estimator, especially once we get into the thousands.
09:39:16 We can do this without Barbies as well I mean there's been a couple papers that don't think we're talking about yesterday, one by blanking on his name he's at Caltech he's working on the DSA 2000.
09:39:33 Big round robin so wrote a nice paper on this and Matt amount of actual also wrote a paper on this as well where we predicted, how well we can measure, Barry on profiles and that you know from that you directly measure.
09:39:46 You know the berry on fraction doesn't function of radius. So I think these two are, you know, non again, nothing is x rays and x rays are great.
09:39:54 It's just they measure density squared. And there's the temperature factor in there as well. So, you know, having a nice unbiased tracer of the baryons will really help answer those question.
09:40:05 But even from the X ray perspective, you know, we're looking at looking at guests that's attend to the seven.
09:40:10 And if you clump gas, if you. This is a calculation that I think I did when I was in grad school.
09:40:18 We if you clump gas, and you have a hierarchy of guests that's going from 10 to the seven down to 10 to the five that gas is still X ray bright, but because you're clumping it, you're increasing the density and Rose squared does win over that t to the
09:40:33 one half or even t to the minus 1.1 if you metal length cooling.
09:40:39 In fact, with the metal and cooling it is the luminosity goes up yet so you can you can push the luminosity down clumping actually will drive your luminosity up.
09:40:52 If I may add a tangential common height, this is such to to Ben.
09:41:00 Ben's point and Joe's question.
09:41:03 We are studying group cycling Lauren mass so that goes from around 12.5 to 13.5 and very similar to stocky work.
09:41:13 JOHN Stuckey and collaborators and we also find that the oxygen, we are trying to look for oxygen six.
09:41:20 And we don't find as much so I think even for slightly lower masters. Also, the guests must be.
09:41:29 I'm just assuming that the guy gas is hotter than what one can see in oxygen six.
09:41:36 So, clearly there is missing cooler into group meeting.
09:41:44 I want it there's a there's a question that's been asked where there's been a lot of activity on slack. And it's showing chin asking you know in her absorption line studies have allergies There seems to be a large scatter in the middle associate the cool
09:41:58 phase.
09:41:59 But how homogeneous is a chemical enrichment of the entire cluster medium.
09:42:07 So.
09:42:11 Hello.
09:42:11 Who wants to address that.
09:42:15 If anyone
09:42:20 has specific, I just making my way through the thread so I'll just repeat the question as it's written from absorption line studies we see a large scatter and gas medalists at in the cool phase and halos of tend to the 13 solar masses, how homogeneous
09:42:36 is the chemical rich, the ICM, how does that impact the mass estimate.
09:42:40 OK, so the Quick, quick answer it doesn't affect the mass estimate much at all.
09:42:48 Because the mass estimates coming from the estimated temperature which usually is not relying on admission line diagnostics.
09:42:57 And so the middle of the city is in a way it's a nuisance parameter and those, those.
09:43:04 Those analyses.
09:43:06 But you can get metal a CD from extreme observations. It's harder, it's noisier.
09:43:13 But on average cluster metal is cities, outside of the core are fairly uniform from cluster there's, there's some scatter, but it's it's nominally, um, you know, 30 percentage solar.
09:43:34 We have to be careful about that because solar changed definitions about 10 years ago.
09:43:36 But anyway, so.
09:43:39 So it's about 30% solar in that area between, say are 500 and about 15% or 500. Um, there's not much variation from cluster to cluster with even even whether it's a cool core and Uncle core, we don't see variations in temperatures.
09:44:13 I am speaking of a thesis project that was just completed on roughly a couple hundred Chander observations of clusters of galaxies. What we do see is, there is that there are people have known for a while that cool core clusters tend to be higher medalists
09:44:21 There also seems to be in an enhancement of medalist city in the centers of non cool core clusters it's not as strong it's not as pronounced but when you stack them all up there's, you know, there's clearly, you know, a little bit of a boost in the center.
09:44:41 So, our resolution isn't great. I mean, we're talking about middle of the cluster, you know, in the region just outside of the middle you know and outskirts.
09:44:53 You know there's there's.
09:44:56 So the you know the profiles are noisy variation from cluster to cluster is consistent with the measurement error. So, so, I actually can make a couple comments.
09:45:08 In order to measure difference spatial variation and medalist city on a smaller scale than just, you know, under 100 kilo parsecs.
09:45:18 Of course it's necessarily not enough photons. And there are there not that many objects we can actually look for metal as the innovation Eddie, but one of them is m 87 were in this core region of me at seven Nora governor has found there are significant
09:45:42 in medalist at from place to place, although it's, you know, it's avoider you know between a third and one, sort of, not down much lower than that. The second comment is getting accurate abilities for clusters, is, is a whole lot easier to getting accurate
09:46:03 medalist it is for massive ellipticals and groups. And the reason is, when you start trying to measure multiplicity down there, you can assume a single temperature model, and that temperature that you fit will pick out a certain set of emission lines.
09:46:06 And then you're trying to fit the melody based on those emission lines, but as the temperatures in homogeneous.
09:46:12 Then you have other sets of admission lines that great. In so doing, joint modeling of temperature variations and medalists at is extremely difficult.
09:46:22 In fact, in the first decade of Chandra and xmm, the results on medalists these were all over the map because people didn't know how to model those systematic problems.
09:46:35 So, as you start marching down, you know to cave in below the making measurement instrumentalist itself is more fraught with systematics, and you want has her hand up.
09:46:48 Hi. I have a question. I think Siobhan found different mentalities in the quarter face and her smaller, no, no, no smaller, smaller systems.
09:47:07 I guess that would be a question for me. Do you mean, do you mean the optical filaments. Yeah. Yeah.
09:47:15 Um, that's hard to do.
09:47:18 It's a mark and I did a new mission line study where we got independent temperatures from other diagnostics and and we're able to make estimates and, you know, The answer is between half of one solar.
09:47:35 So, Norbert himself, now has his hand up and may be able to give expert opinion on middle of city and its variability.
09:47:44 So, outside of the cluster course.
09:47:49 I agree, our measurements with Susan who also showed that the mentality is homogeneous and it is 0.3 solar in these newer solar mentally cities in the older Anderson brothers at 90 0.2 solar.
09:48:05 So, in the personals cluster. We have observations in a different directions all the way to the very reduced to our 200 and 0.3 solar everywhere and also when we compare the metal the cities in the outskirts, in, in a sample of clusters it's always 0.3
09:48:23 solar and about measuring the cold filaments. So this age alpha filaments in clusters are usually surrounded by multi-phase X ray meeting gas, where you can try to determine the metal the city like these bright arms of,
09:48:42 like, right there, X ray filaments, it's very very hard to measure the middle of the city and if you do the simplest thing just a single temperature mother, it was zero point, you get 0.1 solar or or something like that.
09:48:55 But if you fit multi temperature models to these, you can get up to one solar so the data are consistent with one solar.
09:49:08 Okay, we don't we only have about 10 minutes left I want to make sure our panelists, get to pick what they'd like to talk about next perhaps.
09:49:21 They're also can be excused for for starting to run out of steam I don't know if you've exhausted all your opinions.
09:49:30 There's a lot of stuff on slack.
09:49:32 I will definitely go back later today and engage more there too so there's some, there's some good things over there, definitely check that out.
09:49:45 Todd has question.
09:49:47 I was just wondering if some of the experts could comment on this paper by limb mo at all, titled detection of missing baryons and Galaxy groups with the kinetics and I have is all dovish effect.
09:50:02 So, in this paper they claim that in groups. The missing baryons are in gas and the temperature range from 10 to the five to 10 to the six Kelvin. I don't think anyone's commented on this I just wondered, you know what, what are the experts have to say
09:50:16 about that paper. Thanks.
09:50:21 Whenever palace consider themselves experts in that paper.
09:50:26 Well I mean it really the sZ folks I, I'm not an expert on SC I just wondering if you don't even need to be a palace to comment at this time.
09:50:37 There's, there's. It's interesting paper.
09:50:41 I'd be more comfortable doing this, offline not recorded
09:50:48 that I will say this, give it, they're using plank to do this measurement, giving the beam size of plant and the number of objects they have you can predict what the signal to noise should be.
09:50:59 Given the beam size of plank and the number of objects they have you can predict what the signal to noise should be. If there are all the baryons where they're given just you know we know the noise levels of plank. It's a, it's a stalking analysis you can you can predict how well they should be able to
09:51:10 measure things.
09:51:12 And so it's a simple Fisher analysis that's the most optimal thing you can do, and the result exceeds that by several factors. So, I'll leave it at that.
09:51:24 Okay.
09:51:27 All right.
09:51:29 So I'd like to pick up on a thread that Greg has put out, which is that he says I would love to hear a discussion on next recent work in particular.
09:51:41 Well, I'll leave it at that because I too would love to hear about next work and maybe I read, you know, we can organize a seminar or something by him that he can.
09:51:52 So it was an overview. I did mention there is a conversation group happening, which is Halo 21 SZ CGM so anybody that wants to be part of this conversation is absolutely welcome to join that channel.
09:52:05 there will be featured conversations on that subject.
09:52:09 Yeah, so I saw that but I actually would like a presentation along the lines that Megan just gave us. I think it'd be useful for the broader audience, the organizers will put their heads together about this we are trying to figure out how to run a meeting
09:52:23 that doesn't where everybody out before the eight weeks or over.
09:52:27 We, I'll say I think speaking for all of us. We're tremendously impressed by the energy people have brought to these first four days it's been it's blown us away.
09:52:37 And it's always been a lot of work in So we thank everybody. I mean, we're thrilled with the amount of participation and the opportunity, this is giving us to be you know mentioned Norbert orders name and he shows up and answers the question you know
09:52:52 people all over the world so it's actually quite exciting.
09:52:57 So with that in mind, the organizers will consider the wisdom of adding more plenary things, because, yeah.
09:53:10 We'll just have to think about it, but certainly conversation groups are a great place for people to get more acquainted with the latest goings on.
09:53:19 So I can, I mean we, we did a whole webinar for this these particular results or if so if you want I can post that in, I was told it was too long to post in the video section because it's about 45 minutes, but I can post it there I can post in the discussions
09:53:35 discussions and if it asked to I can also give a talk on it as well. They meet the woman wearing he Rosita Halo has her hand up.
09:53:46 This is, This is from the slack for dummies channel.
09:53:53 How do we get, um, I like, i like that channel I need this channel.
09:53:59 For Dummies channel needs to know how, how to TV other channels. So I
09:54:10 browse you gotta find the Browse right here. Yes. So, are you on slack right now hover over channels at the top of all of your channels, there's three vertical dots, just to the right that will appear when you hover over this channels.
09:54:24 Click on those vertical dots scroll down to browse channels and then look at all the channels that start with Halo 21 dash, and you can then join any of those open Halo 21 channels.
09:54:38 Right, yes that was, yeah make it Don't worry about it too much. I too am a dinosaur just said to guide me to this thing earlier numeral people who are remaining silent.
09:54:51 Yeah, well, you know, modern software engineers like to make things kind of secret and hidden you need to know which icons to click and where they are and they sure do that a certain.
09:55:03 So, those of us in the Eastern Time Zone are probably feeling bit hungry. So, if, if anyone has some urgent last words speak now if not, we will say goodbye for now tomorrow is going to be a general discussion, and it's going to be driven by questions
09:55:25 asked. Through a site called mentee that Cameron humbles is going to show us.
09:55:32 And we're going to ask for the conversation groups to update us on the status of their conversations.
09:55:40 it very least, the CGM and FRB groups.
09:55:44 So, that will add some ideas but the idea is every week we're going to have some conversations that we want to feature, these conversations can continue for the whole length of the meeting, but they're going to be particular weeks with those conversations
09:55:57 what's coming out of them. We want people to report on what's interest to the broad group. So, we will start off Friday's discussion with some updates on what's happening those conversation groups, then we'll follow up.
09:56:11 Yeah, and this might be important to some people, Friday zoom conversation will not be recorded or post it.
09:56:18 Okay.
09:56:19 Yeah, just so you know.
09:56:22 And, and it'll be driven by things that are taken and uploaded on a site so if you see questions you like and want to hear discussed in general, you'll have the option to upload them tomorrow it will be just the moderator making the choices.
09:56:37 Ben has his hand up. Yeah, I'm just said, for what are the conversation groups XTGM, there's going to be a discussion at noon pacific time which is in two hours by by Jonathan stern and got the ferryman.