08:42:58 And next up, I'm going to ask, Nick Battaglia to start in on his presentation, and we will go right to Nick, and then we will have a break and then we will
08:43:22 head to the panel discussion probably looking now more like 910. Um, but yeah, and grant. If my video is like, in your view watch me I'll give you a two minute warning, mental, and I'll start giving you faster reactions which seem aggressive, but they're,
08:43:33 they're all nice.
08:43:37 Great. Can you can you hear me.
08:43:43 Can you see my screen. It looks great. Looks great. Okay. Excellent. Well, I can see where we're pressed for time here so I will skip ahead to first saying thank you thank you thank you to the organizers and letting the, especially letting the Z infiltrates
08:44:02 this this this meeting. It's been great. You guys have been very accommodating. And I'd also like to thank all the participants.
08:44:09 Many of you have had discussions with it's been really enlightening and it's been very educational for me so I've really enjoyed these past eight weeks when I could attend and I wasn't say lecturing as it was just an hour ago.
08:44:22 So I will keep the intro as brief as possible.
08:44:27 I hope it's not a surprise to anybody that I'm talking about the sZ because if it is I've done a bad job over the past eight weeks of telling you what I'm interested in.
08:44:36 But for those who don't know what the effects are I'm only going to be mentioning two there are more. I'm going to be talking about the inverse competence gathering of CMB photons and the Doppler boosting OCB photons, as they interact with any free electrons
08:44:49 along their path towards us so the inverse constant scattering is known as the thermal sZ, and this is proportional to the line of sight pressure over here, and this effect is roughly, you know, a factor of 10 to 100 times weaker than our normal CME fluctuations.
08:45:07 The next effect is the kinematic se This is the Doppler Boosie of the CP photons, and that's proportional to the line of sight momentum of these free electrons.
08:45:16 And that is a slightly weaker effect, and they have different scales with the mass of your halo, but this is about an order of magnitude below that from St.
08:45:24 And as we heard from Aurora right I think we can all agree that making maps are making a full map of the thermodynamic properties of the CGM is very very exciting.
08:45:35 And what I hope to convey to you is that we can do that with these various effects I haven't told you yet how we're going to do that.
08:45:42 And what's really nice is that these this inverse competence gathering, or spectral distortion that we see from the thermal se and the Doppler boosting from the kinematic St.
08:45:51 These are all redshift independent right you don't suffer from cosmological Dimi. So in principle, you can measure these out as long as you have large enough samples of to whatever redshift you want.
08:46:03 Right. and I'm particularly excited about the can see because there's been an emergence of Casey detections just over the past decade, so the first measurement of the, of the Casey was actually done almost a decade ago, this was work led by Nick hand
08:46:16 and the act collaboration shown in this upper right, and this was the first four sigma detection. And over time, over the past 10 years, various groups collaborations have made sZr kinetic se detections on various different samples using different estimators,
08:46:33 and these are all. This isn't a complete list. These are just some examples of detections that were made all roughly around sort of forcing my so just at what physicists would call the detection limit.
08:46:46 Right.
08:46:47 The third yc has been measured for for several decades now back into the 80s, but if you'd like to see recent measurements of in particular thermal sec observations of the CGM, I would refer to you to talks by Joel Bregman and Evans canopy echo earlier
08:47:02 on in the workshop, and they were, they were, they were really excellent.
08:47:07 Um, so I mentioned the kinetic as he is a detection of the line of sight momentum. Right, that's not density yet right so how do we get to density. Well, there's this neat method proposed by surely home collaborators back over a decade ago, where you
08:47:23 take a CMT map. Right. And you cross correlate it or stack it on a velocity reconstruction map and what I mean by velocity reconstructing This is something that's typically done for baryonic acoustic oscillations spectroscopic samples, you basically look
08:47:37 look at the overall density of of your galaxies and that relates to their particular peculiar velocities that they have and it's a simple, sort of, in the linear regime reconstruction of where those galaxies actually came from.
08:47:51 So if you have this weighting of galaxies velocity, you can correlate it with the CMT temperature map, and that should pull out the kinetic sZ effect because nothing else, the, the, the primary CB fluctuation shouldn't care about the velocity of that
08:48:04 galaxy, nor should things like dust to first order or say even the throne lest he should not correlate with the velocity of that galaxy. So if you take a bunch of pictures of galaxies in the end map and wait them by their velocities whether they're moving
08:48:20 away from us or towards us. You can then pull out a map of the density if you do this correlation which I'm showing you appear is proportional to the rms velocity of the particular on this philosophy of all galaxies.
08:48:35 So this is something we can actually calculate from from cosmological theory. So, given some cosmology, we can get this amplitude. And then, what's left over is you can measure then the density profile as a function of radius.
08:48:48 Okay. And this was actually first demonstrated on data by some of my collaborators on manual chance money for and the act collaboration. So we have using this particular technique, a measurement of the cumulative free electron density profile, and this
08:49:03 is unbiased so if you have free electrons there it just doesn't depend on temperature or anything like that, any free electrons will be picked up by this by this by this Connecticut's the effect here.
08:49:15 Okay, so what's great is now we have you know the measuring the The Blind Side pressure is easy we get that through the thermal I see that's been done for years, and now we have the ability to measure line to measure density profiles.
08:49:31 Okay, people have thought about previously combining from one city in Connecticut see that was to get more, you know, getting at the temperature of the particular velocity or the optical depth of a particular object, um, what's sort of new now is we're
08:49:43 thinking about this in terms of actually extracting CGM properties so getting at these thermodynamic properties the pressure the temperature, the density profiles.
08:49:54 And we can do this out to large radio. Okay, so that's really nice.
08:50:11 it's a trade off there. Um, so, I know we're supposed to talk about future measurements. These are, you know, within the past six months we put this on the archive.
08:50:19 I think this is this is my way of motivating why I'm so excited about the future measurements to come, because of what we can already do or just did it.
08:50:28 So this is just showing our recent kinetic SC profiles from act, where we took the boss, see mass sample and cross correlated that with act using this velocity reconstruction measurement method or estimator, and as you can see here we have a nice density
08:50:44 profile in the dotted lines at different frequencies in the dotted lines, you can see what it would look like if the gas follow dark matter and I don't need to tell anybody here in this conference that the CGM, and the profile the CGM density looks nothing
08:50:59 like the dark matter Halo, but you'd be surprised what, you know, cosmologists do on small scales, so we thought we'd put this up there anyways. Um, so as you can see here this measurement here is now about it, depending on how you count, whether it's
08:51:13 from the know, or the actual detection of the profile, it's about an eight sigma detection of the Connecticut see so doubling our previous detections.
08:51:25 We also as I said for free get the pressure profile so this is the thermal se, and that's shown here. Again, it's a detriment at the frequencies that we're looking at.
08:51:36 So I just wanted to highlight with here with the TSP you have to be particularly careful about Dustin mission in these galaxies galaxies can't do have Dustin them, as we know, so you have to use foreground separation techniques and I mentioned that a
08:51:51 little bit at the end in the future observations.
08:51:56 And now here comes a full thermodynamic information we have density, we have pressure, we can also get temperature, right, you just, we have our pressure is basically an optical depth time to temperature are densities are optical depth, you take the pressure
08:52:10 this would be the prediction of the various temperature of these galaxies that are about three two or three times 10 to 13 solar masses, and this is the profile that we that we measure.
08:52:31 Okay.
08:52:32 And this, I should mention this is all work led by manual Sham some money for us to find mo do, and Emily Mosher who made it off, was was, was one of the fifth authors.
08:52:46 Now, all this being said these are not measurements of individual objects. Okay, so I hope you're okay with that. These are average quantities. These are for for the entire sample.
08:52:58 And so when you do that, or anything in general, right, it's a good idea to have some model for the stack and so what we do, we do all the forward modeling in this 3d profile so we do this with simulations or you can do this with your favorite parametric
08:53:12 model, I'm looking at mark.
08:53:14 And what you can do then is forward model it through your instrument to get out into the observable space and we have a whole pipeline to do this. So, given your density profile pressure profile, you stick it in here.
08:53:27 Modeling various terms, and your sample, you run it through our pipeline, including beams whether you have a guessing game or the actual beam, and then you do your aperture for telemetry and you get out your to be observe profile.
08:53:41 Okay and then once you have that you can make inferences like how much energy compared to the binding energy was injected in these halos remember the thermal energy or the integrated pressure along the line of sight has memory about all the feedback processes
08:53:57 that went on in that Halo, right so we actually, when we measure this, we have information about some of the physical processes that happen inside that Halo, we've heard a little bit about non thermal pressure support, you know, given your parametric
08:54:11 model you can also if you measured the density and pressure, you can extract out things like the amount of total non thermal pressure and cosmic rays magnetic fields turbulence large bulk flows rotation by if that's in your parametric model and so for
08:54:26 this particular parametric model we made some constraint that it had to be less than 20%.
08:54:32 Another great thing you can do is, these large radius of the CGM have been until now, not, not prob very very well I will say, and so cosmological simulations like lustrous like eagles, like Simba have made predictions for what these profiles look like
08:54:50 right they can't tune their observation, they can't tune their numerical simulations so these observations, because they didn't exist when they made the simulations.
08:54:57 So these are genuine predictions.
08:55:00 And what it looks like right now is you can ignore. One of the great things about Ford Model and as you can also bring it back into, you know, what I would call theory space, you know, thinking about 3d radio profiles, that's what a lot of us like to
08:55:12 about least theorists do, and you can go back and you can make comparisons in that space as well. So focus on the bottom panels here because these are the error bars here at least that large radio are correlated.
08:55:27 And what you can see here is that the the density predicted by these simulations including some of my old, old simulations actually do okay there at the bottom envelope of the density profile as predicted by the simulations, but they seem to be really
08:55:42 lacking.
08:55:44 I would say pressure or they're not hot enough in these outskirts, right, the pressure is much below so this is this, this blue, dark blue curve here with the band is sort of the one sick as the two sigma region allowed by are allowed by the data for
08:56:14 parametric fit. So just a simple parametric model and this is what's predicted by the simulations so the pink and the green and the orange. Okay, so these are this is really neat we're really excited about this we're able to now test these cosmological these large cosmological simulations. And so that's the
08:56:17 results as they are today.
08:56:19 And that's great, but my task was to talk about future observations, so I will say so, the results. I've just shown you are already promising. But this is just the beginning right we're just scratching the surface of the potential what we can do with
08:56:35 the thermal ice in the kinetic se. So these, sort of, you know, six to eight sigma observations we're making a profiles in the not too distant future will be making density profiles that are 5% or less in 10 years from now, we estimate or we forecasted
08:56:53 that we can actually make percent level or so percent level measurements of the density profile, which is, which is really cool. So, this is showing you some of the forecast I did a while ago, I knew I was going to give this talk.
08:57:06 Four years ago when I wrote this paper and. and this is just showing you what we can do with some upcoming, I would call them stage three experiments and stage for experiments cross correlating with various surveys.
08:57:19 The survey we had back then, we did for the, for the, for the yellow is the CMS survey for the, for the gray bands, this is the Desi survey which is on the sky now.
08:57:30 And these improvements are coming from many things right they're coming from, potentially better resolution of are seeing the experiments, coming from lower noise from are seeing the experiments and just having larger galaxy samples.
08:57:42 Right. So, again, percent level measurements and about 10 to 15 years from CNBC stage for cross correlate with Desi or maybe something better, and definitely sub sub percent level measurements of the pressure profile, using these techniques.
08:57:58 So that's, that's really cool. And so where are these coming from I've mentioned this before, I just I didn't want to go into too much detail about the experiments, but for CB observations were photon noise limited, so what that means is you want to get
08:58:11 get lower noise maps, you either integrate for longer, or you throw more detectors on the sky and that's what these future experiments are doing so see cat prime Simon's observatory SPT 3g advanced x, we are putting more and more detectors on the sky,
08:58:30 sky, every day to get lower noise CB maps, right on CNBC stage four is another step above that.
08:58:38 The actual growth in the number of detectors on the sky actually follows like a Moore's law. So if we just keep waiting a little longer the measurements are going to get better and better we're packing more and more detectors into our cryo stats we're
08:58:50 making larger and larger fields of view, so we can pack more detectors in there make larger survey telescopes. So we're getting more detectors and another advancement is we're getting more frequencies on the sky so more frequency bands, the more frequency
08:59:02 bands we have, the better we can do things like components separation.
08:59:07 Another advanced if we think a little further in the future is higher resolution so the measurements I showed you, right we're resolving maybe one or two elements inside the real radius out about Richard point five.
08:59:19 If we got to lower richest we can, you know, we can actually expand that get many more resolution elements inside the real radius but if you really want to get down to sort of the 10s of kills per sec level, you really need bigger dishes so this is at
08:59:32 last here towering over the ALMA, the Alma telescopes right this is potentially a 50 meter dish and the Atacama Desert. There's also seen the HD which is another one, which is even further field.
08:59:46 This is again, you know, like a 5025 to 50 meter dish, improving the resolution that we have by factors of five to 10. Okay, so these are two big improvements on the CMV side that we are looking forward to.
08:59:59 And another one that we're looking forward to is just larger samples right so with the beer Rubin observatory coming online the next couple of years on that will produce a large number of getting like a huge galaxy samples that we can then cross correlate
09:00:11 with and beat down some of this noise, especially on large scales, because those error bars also some of them reduce depending on where they are when Angular scale you're looking at they reduce like one over square root and Desi coming online will be
09:00:24 great if you want to do this velocity reconstruction method you need spectroscopic, and you spectroscopic sample. So Desi is producing a huge spectroscopic sample compared to what we have already with boss.
09:00:36 And just to be a little provocative, right. So, looking ahead to see me as for this is work that Colin and Marcello and the Cato survey review for CBS for worked on I helped out here a bit and we had some input from lots of simulators.
09:00:51 This is just showing sort of the error bars we get for a see master Desi like sample at different at high redshift so ratio for one, right, and this is showing you the various predictions from the current cosmological simulations.
09:01:04 And I guess this is provocative maybe it's not you know CBS for will rule out all current models I say current models of galaxy formation.
09:01:12 But then I put down, we've already kind of started to do that already with act.
09:01:16 Yeah, so is the emoji.
09:01:20 This is showing you, You know, we're going to have these huge Signal to Noise numbers, we can actually start doing fun things with that right like there's no point in measuring sub sub percent pressure profiles and density profiles, you can actually start
09:01:32 to subdividing them up right if you have this as a function of redshift your favorite galaxy type of property, we can start looking at how the pressure density and temperature profiles look like in these different samples.
09:01:44 So that's, again really exciting.
09:01:46 This is an example for LR Geez. This is an example for quasars we can do this at redshift too right we have enough quasars with Desi that we can actually reconstruct the CGM of a quasar rich have to, and it's still running amok properties that's that.
09:02:00 I think that's really cool. I don't know, Maybe you do too.
09:02:05 Oh, here's another sort of signal to noise propaganda plot that Colin and I put out in in our white paper that we wrote for the Cato. This is just showing signal to noise of a different estimated This is the projected fields estimator.
09:02:18 If you want to know what this is and the latest measurements, I encourage you to look for Collins talk from a couple weeks ago, they made some really nice measurements and strides forward with it with this.
09:02:29 You can see here this was started where we made our first measurement It was around 363 sigma.
09:02:34 We were supposed to get to 100 sigma we're still getting there we're not quite there yet, but this is sort of the trajectory that we expect maybe you shift these dates a little bit because people get busy and we haven't actually gotten to doing these
09:02:46 observations yet.
09:02:49 I will, I will point out that, again, this is a stack. All these observations are in a sec Jessica Marvel's done.
09:02:57 The. What's the signal to noise gets really high when you get really high signal to noise you just have to really worry about these little things I think he didn't necessarily have to worry about so much when we were stacking it as a six sigma, sigma.
09:03:10 And so, Emily. Moser who's a post was a student who's working with me, and not a full stack yet, but eventually she put out a paper it's actually out on the archive today.
09:03:22 We hope to put up a video very shortly, on, on the, on the site or on on on slack and on YouTube for everybody look at this is just showing you that they're modeling choices that you make from modeling that stack really start to become important even
09:03:38 when you go to, not even CBS four level but even like Simon's observatory see cat prime advanced act, they really start to become important you can potentially bias your influences.
09:03:49 If you don't include things like contribution from other galaxies around your galaxy, or you don't actually take into account that the distribution of galaxies actually matters for things that you know don't scale linearly with mass right an average mass
09:04:06 will cut it, we actually want to model the full distribution of your galaxies.
09:04:10 And this is a slide just to say, component separation dust is important, but we do this is a well studied problem in CMB in the CME community, there are solutions that are already implemented on data.
09:04:24 We expect them to work on, you know, higher fidelity data. But, you know, and I'm optimistic they will, and an advantage that we're going to have is these future CB surveys will have a much larger range in frequency coverage which makes this job even
09:04:42 easier.
09:04:44 So, I will leave you with this right I think we're all in agreement. I my task was maybe to convince you that the the SEC will be important for understanding the CGM in the future.
09:04:57 I think we all agree that thermodynamic profiles are important so let me pose a couple questions for the CGM community. What if I tell you we can measure these profiles out to large radio into the transition between the AGM and CGM, are you, is that something
09:05:12 you're interested in, maybe with an emoji or thumbs up.
09:05:16 Are you interested in measuring these profiles, the percent level.
09:05:20 Yes. Okay, good. And then, are you interested in then taking these measurements and subdividing them into your favorite galaxy characteristic whether it's you know start forming galaxy versus crossing galaxy, etc etc post Starburst, you know, subdivision
09:05:36 upon subdivision of galaxy UB can do that. So that's really really neat and something that I had didn't have any slides for but came up and actually discussions this past week with folks on with this actually happened on Monday, and then again when we
09:05:52 start discussing the parametric model is, I've done some back of the envelope calculations and it looks like.
09:05:58 If we have some tracer of the rotation of the CGM, in principle, we can stack and measure the dynamics of the CGM out to large scales, this would again be the kinetic se.
09:06:14 And so if you have some way to say this galaxy is rotating this way we can actually, if we have enough galaxies, the signal to noise is there to actually measure the rotating CGM in the next couple years.
09:06:28 So that's, I think, exciting.
09:06:30 So I just leave you with these questions and I'll let you tell me if you know future se observations will you know transform our understanding of the CGM.
09:06:42 Thank you.
09:06:45 Yes, yes is the answer.
09:06:49 Um, this is, this is a great talk, I love to today's talk it allows me to kind of dream wildly about the future, from the near term what you were just talking about dynamics of the CGM all the way to 2036 which will probably turn into 2044 honest.
09:07:08 Okay, so what we're going to do now is we are going to take a short break I know everybody probably wants one needs to digest some of that information.
09:07:19 Look at the slack digest was there react to the questions pose questions. We will come back in five minutes so 12 after the hour.
09:07:29 Okay, so we'll come back at 12 after the hour I'll introduce the panel, and we'll get our exciting discussion going. Thanks again to both speakers, and we'll see you in five minutes.