08:05:02 Okay, good morning everyone. And today is Wednesday of galaxy evolution week, and we have four tutorials today.
08:05:13 We have a full schedule, so I'm going to try to make this introduction brief
08:05:20 new image from David rep key.
08:05:23 Keep on populating the beauty channel Halo 21 beauty Slack channel and I'll select something simulation oriented for tomorrow's image. So we will rush through that, and I will just note trivia time we'll, we'll turn it around and socializing time will
08:05:46 at 4:30pm. And I'll talk more about that and we'll have a link tomorrow.
08:05:49 So today, I'm happy to introduce for people who have volunteered and been asked actually, to give tutorials and we are going to have a busy schedule. So I want to repeat have people remember that all of these are going to be recorded.
08:06:12 And so if you miss one if you're in a breakout room afterwards if you go to another tutorial to join and Elisa or john or Chris or Ferrari.
08:06:22 You can always come back and see the recordings of these tutorials.
08:06:27 So, each tutorial is going to be a 20 minutes of presentation and then five minutes of questions and then you know, push you off to the tutorial room and.
08:06:35 And then we'll move on to the next one, we'll have a break, approximately between like 855 and nine o'clock. So, um, and Elisa, are you ready.
08:06:48 Yes. Okay, I'm going to stop my share.
08:06:52 And I'm going to turn it over to you.
08:06:55 Mm hmm. Cool.
08:07:04 Yes. So, Hi everyone, today yes we're going to talk about defects of environment on satellites, as the images at the bottom of the slides are meant to evoke jellyfish galaxies from the change of 50 simulation.
08:07:19 But this is going to be a tutorial about effects of Hilo environment so we are going to focus on Saturday says that slides for orbits in high density environments as the ones that we typically find within say division radius of halos of groups and clusters.
08:07:37 So what I have in mind is to propose a mental scheme, a framework to tackle the following fact all components of the Galactic ecosystems. The style component is MCGM, the matter halo, halo of the host to remastered because of the hosts are all interconnected,
08:07:53 they're going to do this from the perspective of satellites only for today.
08:07:58 And so with this mental framework, we're gonna discuss what effects we're even talking about when mechanisms have been considered as possible causes for such effects of his some physical dependencies, but I want to highlight how do you recognize that
08:08:13 structure complicates, a lot, our interpretation.
08:08:17 And finally, I want to close with the flesh net results which we resolved, which we call the direction if you will see from time to time things to keep in mind as a note.
08:08:27 So, the ideal environment is pretty clear when we say look at groups or clusters of galaxies is still alive, or center mass, like in this image here. There is a beautiful galaxy at the center center the potential well at the minimum.
08:08:43 There is a beautiful galaxy at the center at the center of the potential well at the minimum usually is the most massive are Muslims and it's surrounded by a smattering, or thousands of satellites, which are what we are thinking about that our dynamics
08:08:54 is actually domain dominated by by the potential which is dominated by their matter Angus. So we have the matted gasps and stars. And so this immediately suggests us that when we think about satellite host interactions we should move them in three categories,
08:09:08 gravitational hydrodynamic goals and Eric this call it radiative. So gravitational and say interaction with the host potential like take the stripping or without the galaxy title shocking hydrodynamic with a host intro Hello gasps like run pressures tripping
08:09:30 on or other galaxies, and then put on the head of radioactive anything that I think could, in principle effect galaxy satellites evolution. So because they are in a given ambient radiation or they can be affected by directional sources of radiation say
08:09:38 from the central Aegean from the central surgeon at the center of the host, or maybe their evolution is affected through the our cooling because of the enrichment of the Ambien Gus.
08:09:49 And so for this audience we're really more thinking about the hydrogen me, call me productive interactions. And it's all about the properties of the intra Halo gas, not just guest density, but also gas temperature or gas multiplicity.
08:10:06 And also satellite evolution may depend on how this intro Hello gas is when would you use orator genius, and how he moves.
08:10:14 How Celtic or turbulent it is as you can see here in a in velocity fields of over, even energy dissipated through shocks.
08:10:25 Now when we think about the effects of environment, what are we thinking about.
08:10:29 Let's talk about a couple of observational effects, observe facts, mostly observations of both in the sky and more recently also realizing simulations.
08:10:38 So we're thinking about properties oh god x is like some ufology some information activity and guest content, but also possibly still our sizes government the lizard tease X ray luminosity of their hairless Adrian activity stellar to enormous religion
08:10:53 in a natural, and I'm going to really flesh, the result is Saturday's galaxies in groups and classes have been observed to activate, on average, lower step from issue rates greater color higher contractions lower age one guest content, limited government
08:11:08 obesity, reduce X ray Hello mission suppressed, on average, agenda to higher self to amass relation in comparison to similarly massive. And I looked in the field.
08:11:20 So this was very fast. This is all the state of the stuff that field, you're going to focus on the three more important things more find yourself permission activity and gas content.
08:11:34 Thinking about Star morality.
08:11:34 It's an observational fact that the fractional Sirota like galaxies higher and higher density environment. This is the famous Dressler relation or morphology density relation.
08:11:43 If you count how many the relative fraction of electrical arrest you know God sees is higher in higher density environment than a low density environment so if you measure how crowded, they aren't based on galaxies, or how close you are to a central trusted
08:11:57 and they're higher than spiral loners got axes I typically start forming. So you can see this when you plot quite traction but you stand on the different planets or different restaurants, you can see both observational data in grey, say here is from cosmos
08:12:14 and candles and from simulations like the engine illustrious what they want you to notice is that we looked into the tensor massive galaxies and more sister for me, and above 10 to 11 solar masses galaxies and mostly question is to both the observations
08:12:30 and already addressed at 1.5 or so.
08:12:34 And he's also doing simulations recently.
08:12:37 However, this is true when we look at galaxies, combining satellites and central, so their statement, low mass guy is typically start for me, it is true, unless they are satellite, and so you should take a contraction thought and you divided in central
08:13:03 Time satellite, you actually see that the contraction of low mass galaxies is much higher for settlements than Central's. This is again as the SS data in Greece tangi 300 in black.
08:13:05 All right.
08:13:07 And we are looking at satellites as galaxies which are orbiting within say 10 to the 12 pretend to the 15 points of Solomon sailors final observation of fact that they want you to be aware of satellite guy takes up lower h1 fractions then their field
08:13:15 counterparts. You can see here at one Mars rovers that are massive nog as a function of satellites that are mass data points are observational results from x gas on the top of alpha on the bottom and curves are from tng Central's are in reddish pinky
08:13:40 and satellites are insane and you can see that central time higher gas fractions does depends of course on where you're looking at, this is way different between x guys and I've had funded the beam size, for example, in tng, this is happening while our
08:13:56 galaxies are beautifully around precious shift as you can see on the left and eight one map of a group of a group of guys.
08:14:05 So what's going on.
08:14:07 I think it's it's useful to simplify a little bit the perspective. And I would argue that is not a simplification, I would argue that it is all a matter what happens to the gas into the guests availability.
08:14:19 So this is actually generally true to up to the second order I would say in galaxy evolution is also doing this context. So if you think about self promotion activity and gas content of course yes, obviously connected modulates a cooling and the availability
08:14:33 of gas and specific phases, but also when you think about morphological transformations.
08:14:51 Refresh or transformation are strictly connected to availability of gas, because you cannot have a persistent morphological change unless you avoid new star formation because new star formation will replenish stellar disk.
08:14:55 And so, you know, reversing again any morphological transformation that you might have had by just, you know, kicking the stars and changing their orbits.
08:15:06 And so, let's focus on the gas content and gas availability and instead of talking about the buzzword that you're funny here in environmental studies.
08:15:30 I just ask us what can happen to the gas of satellites, both the ISS and the CGM can be consumer the people can be heated up or cool down. It can be ejected, it can be compressed.
08:15:29 It's replenishing punishment can be suppressed, or it can be removed or stolen. Okay, so the first four happens in Central's are filled galaxies are you Central's and feeds us unanimous.
08:15:44 And they are due to a zero to two internal processes, but for example the suppression of replenishment of gas, or fuel of gas is typical of satellites and removal it's also just typical of satellite.
08:15:58 So, for example, gas can be depleted your star formation can be to that point objective the internal feedback supernova supermassive black holes, but even can be compressed funneled into the center guys you get galaxy galaxy merging speech, I would say
08:16:12 different than the host environment interaction we're talking about.
08:16:24 For centralized replenishment of gas can be suppressed in the sense that they can be stopped the secretion cosmological or from the surrounding can be stopped.
08:16:25 Just because they are flying into potential well of a more massive guy and gas can be removed the title strip been there and pressures tripping over repeated encounters with other satellite.
08:16:37 So thinking about this famous buzzwords people have called harassment is repeated encounters with other galaxies, and they're called a combination of depletion get start formation and lack of replenishment they have called them starvation strangulation.
08:16:53 The point is that we satellite we have so much more complications, because for example you can heat up and eject the gas of satellites because of interaction with the effects of feedback, not from the satellites by so from the central of the hosting which
08:17:09 are orbiting around pressure stripping can remove gas but can also compress it at the same time.
08:17:17 And so as you can see all of those happen at the same time. Simultaneously, sometimes at the same time in the sense that we can even see set of simulations that formation happens at the same time as trooping of both dogs Angus, and the offense can combine
08:17:33 together sometimes constructively or nouns. For example, if you heat up the gas via supernova feedback you may make it less gravitationally bound and then it's easier to remove it save your stripping title or run pressure.
08:17:49 And so then the question becomes, okay, which phenomena are most relevant and it depends on what effects you're looking at, I would argue that the physical as you were certain physical mechanisms say like exactly right Brett brown precious European our
08:18:05 strongest are not necessarily exactly the same as a physical regime where the effects on galaxy properties are the largest, because this is all complicated but they are apricot so structure, we can do to it to this in a second.
08:18:18 But that would say, let's focus on the physical regimes where the effects of the own galactic properties our largest, or let's try to find some causality.
08:18:30 So resembling PNG.
08:18:30 The lower age one gas fraction are easily explainable by ambitious tripping, so we have run pressures trippin properly capture into simulations, and they produce jellyfish jellyfish galaxies are observed, they are beautiful and you can see them with these
08:18:48 tales.
08:18:48 So this is another way of looking at a few guys from TNT. Some look like tablecloth where the gas is tripped up from the side of the table there looks like.
08:18:58 Very elongated small stream so guess.
08:19:01 We can go into simulation and actually look at what is the fraction a jellyfish galaxy among satellites.
08:19:08 We can do it visually inspecting the simulations and we can say for example that the lower disciple a mass, or the larger the host mass, the larger is a fraction of jellyfish, but we don't see effects on redshift.
08:19:23 Think about the dependencies of contractions, the contraction of sadness depend on host and satellite properties, but also revolutionary state. This is a summary that both observation and simulations agree upon for Lomas galaxies, lower center mass implies
08:19:42 higher and higher host marketplace higher contractions higher or lower contraction if you fix everything else.
08:19:50 I think Saturday mass for normal galaxies.
08:19:54 Lower cluster centric distance means larger contractions, a longer time since info also imply larger contractions.
08:20:03 As I said, these are quantitatively supported both by observations like SPSS data in this class here, or simulations like TNT again hearing speakers, don't want you to look at the class I mean that these are too many but I leave them in the slides.
08:20:20 But what I want to focus is maybe, as these dependencies and some of them are clearly very well compatible with the dependencies of run pressure and pressure is larger, the larger is the medium density.
08:20:34 And because like because of this question of whether V is the relative philosophy between the gas in the satellites and the gas, we decided it is heating up on.
08:20:40 So you can imagine that larger host mass imply higher density, and therefore higher on pressure, high hopes masters in higher higher satellites orbital velocity and therefore, higher impression and lower cluster centered distances employee higher intensities
08:20:56 and higher impression. So these are, of course, very useful, but they're not the whole story.
08:21:03 Because what we see at the certain point and we can think about this physical mechanism acting at a certain point, I should is there is off 2 billion years of complex evolution, read for me remind you how complex is the erotic hypnosis structure.
08:21:18 This is the assembly of a group of classes.
08:21:21 10 to 14 is two gigantic groups that are going to merge together with smaller groups, which are merging with the bigger one. And the satellites are orbiting in both these groups, and in the final host.
08:21:34 So I want to talk quickly about three facts preprocessing first base and backsplashes.
08:21:41 So pre processing is this idea that when we look at satellites in a given host say it rushes you know this might have fallen, a central.
08:21:52 Or they might have fallen as satellites of other group, and together with their little group of fallen into the final host.
08:22:00 So pre process independence center mass of the satellite and host mass, where you're looking at it, so we can use the simulations, I can tell you for example that that could entertain G.
08:22:11 More than 50% of 10 to the ninth into the Telstra mass galaxy which we find today in groups of 10 to 14 have been satellites of other massive host before falling into the final hosts.
08:22:25 So this is a number of effects right. Firstly, progressive galaxy mayhem it dude galaxy last interaction for a very long time, but they might have fallen into their current host already affected already quenched already steroidal already devoid of gas.
08:22:42 So we can measure all these in the simulations and whenever we look at galaxies even the observation which are quench satellite rushes zero we cannot do they couldn't the satellites are didn't quite have Central's, and if they wanted a Saturday they quench
08:22:55 while they were orbiting in this host, where we find them today, or even another host which then fell into the host where we found him today. And he's really quite just activating the current host of they've been pre massaged by some other interactions
08:23:09 before. So this give us a thing to think about.
08:23:13 Yes, more massive hopes and more efficient at affecting satellites is to engender contraction guess fraction of right you've got changes, but this is a concurrent of two reasons.
08:23:24 The physical mechanism there may be responsible for this may be stronger in higher density environment, but also the more massive halos host or the ultimate product of the radical groups obstruction.
08:23:35 And so, they have many more. The high fraction of their satellites have been pre processed.
08:23:43 Another thing that I want to point out is this idea that face space we disappointed when talking about miss you in Andromeda. So Saturday the fell into the current toast a longer time ago I typically found closer to their whole center.
08:23:55 This is written velocity vs class substantive distance and the red guy satellites are galaxies that fell into this classroom you're looking at. billion years ago.
08:24:05 And so this is an impact that the effects of environment depends on where satellites are located at a time of observation. We could even translate this by looking at the star formation histories of dwarf galaxies and we see abuse trends of this stuff
08:24:21 formation Easter is on the right, in PNG, depending on where we find the Saturdays whether we find them very close to the scientists, or or not.
08:24:31 And this is again this gives us something to think about.
08:24:42 Satellites closer to the host centers. Yes, are more affected by environment but this is again, it's because maybe two reasons. Physical mechanisms like current pressure stripping may be stronger in higher density environment, and therefore closer to
08:24:48 the cell center, and satellites orbiting closer to the centers have typically spent a longer time, and so they have longer aliens billions of years of wholesaler Scotty direction.
08:25:01 And finally, There's plenty of backstage galaxies in the world. And like those we mean galaxies that the pure Central's and in the field, but actually have been in the past satellites have nearby, but not too close by groups and clusters, we call them
08:25:19 max flesh, the complication is that I skip that communication is that the contaminate our samples and our understanding of Central's and few galaxies.
08:25:27 So if we were able in the world to even remove from observed galaxies, the ones that have been affected by some prior satellite membership. So removing the next batch we would even get.
08:25:41 Yeah, the contractions but it depends.
08:25:47 Alright, so this was all about I wanted to say when thinking about environment, very complex, and I want to close with that flushing a result. If I have a few minutes, still.
08:25:56 Yeah, you have about, you've got enough for 19 minutes, so you have 25 minutes so go on for a couple more minutes and then we'll move into the breakout room.
08:26:13 That is really putting together many of the things we have talked to you about. And to say, I find it is is the quintessential manifestation of the connection between the CGM properties and effects they can be can have in on satellite go to properties.
08:26:24 And so we have queried SPSS data in relation to the quenching of satellites. And we found that the fraction acquaint satellites depend on their location with respect to their central galaxy.
08:26:36 So here is your typical Halo the mighty yellow off caches Hello, suppose you have a central galaxy, you can always define a foot to my to call me know minor and major axes, even if it's not even if it's an elliptical.
08:26:48 And then you have galaxies in different locations so you have galaxy say along the minor axes of the center, or, or along the major axis, the major plane of the center.
08:26:59 And so, we found a dependence on weather satellites are where they are with respect to the plague of the Central.
08:27:09 And so, I don't know whether we managed just to do it now live, but I would like you to at least think about, are good to maintain your calm and maybe just will have, I can, I can share the code and the chat.
08:27:21 Just a moment here. Yeah, I know the answer.
08:27:26 So I want you to try to say, which satellites are so did the second point is that satellites are very much quenched, okay.
08:27:38 No matter what satellites are relatively less quenched, I couldn't tell you, the one that we are found along the minor axis of the central are the ones that are found along the major axis of the center.
08:27:54 I hope the question is clear.
08:27:58 And I don't know we can have a couple of sec, a few seconds to think about that and then whether people are voting, or not, people are voting. The votes are the votes are pouring in about this because Elisa gave her provoking here at CU, and the results
08:28:22 were difference. I think the the results will be different here. He could experts. Okay, excited.
08:28:25 Just do we want to say that we may end up quitting today.
08:28:28 So only 20, okay. The votes are still pouring in. The numbers are going up rapidly so maybe give people another full minute to kind of contemplate what they think their answers should be
08:28:42 will have Chris, get ready he's going to start in about three or four minutes.
08:28:48 And you can see the breakout rooms
08:28:53 and Elisa has one.
08:28:56 So, I think I would give you the answer. Okay, okay. So this is, this is, so with 35 people having voted 56% same minor access. Oh, it just changed 57% say minor access 58% say minor access is a good 39%, a major access, very good sorry I went away.
08:29:17 Very good guys. The answer is indeed. One is a London minor access so we have an audience of super experts. So what we think is happening is the following.
08:29:28 So, in SF Saturday's contraction or lower along the minor axes of their Central's, you can really see tear contraction and functional orientation. The my direct Susie's here, and it says model for his mom phenomena, have a few percent, but the statistically
08:29:41 and for halos host, with relatively more massive supermassive black holes.
08:29:57 And we have the same TNGE Olson tnz, we have another trapping modulation, for which the quaint fraction of satellites is a little lower, along the minor axis of their central.
08:30:10 And so, Indians we could go and ask Is this a manifestation of Alaska. In phenomenal, or a hosted or phenomenal. And we really think it's a wholesaler phenomenon because we don't find the same modulation in the last years we've had the same large scale
08:30:23 structure of tng but different feedback, the modulation exchanges stronger around placing galaxies in the wrong Central's with more massive and more energetic supermassive black holes and the modulation is certainly driven by galaxies which quench in
08:30:38 the rushes zero coast. So what's happening within this is that manifestation of supermassive black or feedback from the central.
08:31:06 around galaxies, and the outflows and effects are coming out in a bipolar manner, even if the feedback injection is as a topic.
08:31:06 In practice, what happens is that supermassive black hole feedback from the central galaxy listing 20 cars, lower density region in the silicon galactic medium around the Central's, and particularly so along the minor axis.
08:31:19 So if we then plug the gas over density as a functional orientation by stacking many healers, we still see a difference.
08:31:28 And I think that this lower density affects the possibility of quenching galaxy's lower ambient density means lower run pressure stripping of satellites, less gas removal lower quaint fractions.
08:31:41 I thought that I had to show you this because it's incredibly cool, and maybe the interpretation is wrong but this really is a manifestation of the interaction between the supermassive black holes at the center, affecting the CGM, which in terms of fact
08:31:55 that if we understand it correctly affects the evolution of satellite galaxies. Excellent, excellent point to finish the main session on and I will have those interested, go into the breakout room I know there's some satellite experts here.