08:05:05 And welcome back.
08:05:07 hope everybody enjoyed their three day weekend.
08:05:10 Maybe even for some of you it was science free, but now we're back.
08:05:14 So it's interesting, you know, we have this policy to start five after the hour it's a lot of fun to watch the participants number.
08:05:24 You're all conditioned to now come at five after the hour.
08:05:28 Even though we built in this grace period you've caught on to us.
08:05:36 So
08:05:36 week six is how this gas flow in the galaxies week.
08:05:46 I guess we decided over the years galaxies, breathe in a way they inhale and the exhale.
08:05:48 Last week was exhalation which tends to be spectacular inhalation is more subtle, and yet without it, galaxies couldn't exist. So this week, part of what we're trying to figure out is how that gas, got into galaxies to begin with.
08:06:06 It's the sixth week of our eight week program.
08:06:10 It's amazing how much I've learned in the last five weeks, and we have three more weeks to go, I think we're going to set a record for learning and an eight week period from from listening to all our speakers and panelists.
08:06:25 Before we get to today's keynote talk,
08:07:58 Today, our keynote speakers Kate Rubin from San Diego State, and she has been a leader in how gas flows in and out of galaxy she could have given a talk in both sides of the respiration process, which is going to be talking to us about how gas flows into
08:08:18 And we will have a panel discussion fire talk between Nicholas later freak of him before going Rudy and cloud Andre Association here.
08:08:29 So, with that said, I want to yield the screen to Kate, who will introduce us to how gas flows into galaxies.
08:08:42 Please take it away
08:09:28 First thing I have to say. This has been a phenomenal workshop. The organizers have done amazing work putting all of these activities together for us.
08:09:40 And I have indeed felt inspired over the past five weeks and a way that I have not for quite a while before that so thank you organizers, very much.
08:09:53 And I'm really happy to have this chance to talk a bit about the empirical or observational answers to the question, how does gas flow into galaxies.
08:10:09 Now one thing about speaking of it later in the workshop is that your question gets answered by previous speakers, so it started all the way back in week two, when Todd trip told us that, at least in the Milky Way.
08:10:29 There's a lot of evidence that the gas that is flowing inward toward the Milky Way it's this is multi phase it's detected in each 121 centimeter, a mission, but also in low ionization metal lines, intermediate ionization battle lines, and highly optimized
08:10:51 models, like, oh six.
08:10:54 So that's one thing to keep in mind as we move forward here.
08:11:00 Then in week four.
08:11:03 Mary and her keynote topped impressed upon us, the complexity of the morphology of gas flows toward the Milky Way's disk. So here she was talking about large, complex is of high velocity clouds, which are composed of multiple clumps within these large
08:11:30 complexes, and then are surrounded by a whole bunch of additional smaller clouds.
08:11:39 And she also made the point that if you increase your spatial resolution, increase the spatial resolution of your observations, you're probably going to be finding some even the smaller clouds.
08:11:52 So that's another thing. She.
08:11:55 Another thing we should keep in mind as we move forward.
08:12:00 And then finally, and I can I stop you for one second, you have, it's not a big deal but there's this build order.
08:12:22 anything but just so you know, build order, I don't know what it is, oh it's down in that corner there. yes.
08:12:21 Okay. Sorry. Thank you for letting me know.
08:12:27 Um, let's see if I can get back.
08:12:30 Is that better.
08:12:32 Okay.
08:12:34 All right.
08:12:38 Okay and then also in week four believe both said that gas accretion occurs vertically vertically over the disk and not at the edge of the desk. And here he was specifically objecting I think to this blue stream of creating gas that falling towards this
08:13:01 galaxy along its major access and instead was arguing that gas is a created primarily vertically toward the galaxy disks, and that accretion it's triggered by condensation.
08:13:21 And that accretion is triggered by condensation. That condensation sorry is triggered by galactic fountain flows and which trigger condensation of the hot coronal material.
08:13:33 So, my initial reaction when I saw this was.
08:13:39 Do we have two competing models for how gas flows into galaxies here.
08:13:48 And I'm not quite sure that that's the case.
08:13:52 But let's think about it a little bit more.
08:13:55 So first of all, neither of these images show actual model models they're both schematics.
08:14:07 But the image, the model that is evoked by the image on the left here was laid out in marinacci at all. 2011.
08:14:16 And perhaps has some similarities with the predictions of the simulations of Kim and Ostreicher, who are doing very detailed high resolution simulations of the interaction between star formation in the disc near the solar neighborhood in the Milky Way.
08:14:39 And the coronal material, just above that.
08:14:44 And one of the thing I find really intriguing about these simulations, is that the sense of the velocity of the gas above the disk changes with time sometimes it's going away.
08:14:58 sometimes it's falling back in.
08:15:03 And so that has some similarities with the predictions of marinacci for Denali at all. And I do hope we'll be able to hear more about the predictions of these simulations, either in the discussion today, or on Thursday.
08:15:22 Now, the image on the right here, is also not a model, but it is perhaps meant to evoke the predictions of cosmological simulations, which have predicted for some time, that large scale flows of gas tend to accrete onto galaxies along the major, their
08:15:49 major access.
08:15:52 And this. This figure is just showing one such a prediction that Dylan showed us last week, the figure by sob in Peru, and it's showing a map of the gas radial velocity around this galaxy a redshift point five in selected from the illustrious T and G
08:16:16 simulation. And indeed, they're finding inflows tend to occur along the major access, whereas outflows occur along the minor axis.
08:16:27 So, I don't know that these two models are competing they shared certainly share many aspects, there is a recycling of gas. In this diagram here. So, this model is perhaps inclusive of the predictions of this model, and perhaps really the question is
08:16:52 about how important major access flow is relative to vertically directed flips.
08:17:03 So in principle, we should be able to answer that question observation.
08:17:10 And really what we want to do is figure out what the inflow version of this function is, this is a function that Dylan said we need to measure to characterize outflows.
08:17:27 This is the mass outflow rate as a function of distance from galaxies, as a function of as a new source angle or viewing angle I should say as a function of velocity of the gas as a function of phase and metal content.
08:17:48 So really what we want to do what we have to do is characterize the mass in the flow rate onto galaxies in the same way as a function of these same parameters.
08:18:05 Of course, Dylan also brought in other parameters that I'm just going to totally ignore here.
08:18:14 It's it's even more complicated than this.
08:18:17 But, this is our goal.
08:18:21 We'll just leave it there, we want to measure the mass inflow rate as a function of these parameters.
08:18:30 We're not going to be able to do it, but we're going to take some baby steps toward this goal in the top today.
08:18:40 And we're going to be able to make some progress first by looking at what we can learn from measuring abundances of each two regions.
08:18:52 Then we'll look at insights from studies of neutral hydrogen, and 21 centimeter and mission.
08:19:00 And then, finally, we'll take a look at insights from absorption line studies of galaxies.
08:19:10 So before I proceed.
08:19:14 If anyone. I really don't mind answering questions as we go so please feel free to shout it out. Maybe I'll pause a few times during the talk.
08:19:27 Alright, so let's start with these h2 region abundances what can we learn from making this kind of measurement.
08:19:37 So, we can make some progress. If we have spatially resolved information about age to region mental abundance.
08:19:49 And we have that now, thanks to the Sloan for manga survey, which has obtained quite deep, if you integral field spectroscopy, a sample of 10,000 nearby galaxies.
08:20:08 And so, Hawaiian at all has taken advantage of this to identify regions in these galaxies, which have anomalously low metal of cities.
08:20:22 So how they do this, they first have to establish the baseline relationship between local medalist city and stellar mass surface density in these galaxies.
08:20:39 And so they demonstrate how that is done using this figure.
08:20:45 So for instance, for all galaxies with a total stellar mass of 10 to the 10 to 10 to the 12 solar masses.
08:20:55 They plot, the metal entities they measure in every sproxil in those galaxies versus the stellar master if its density in those same spec souls.
08:21:08 And this pink Ridge here shows the mode of that relationship. So that's where most of the galaxy most of the stack souls in those galaxies ally.
08:21:22 Done. They identify regions which are significantly offset from that relationship.
08:21:32 And up here in the top, they're showing us maps of that offset so the color bar shows us, this delta medalists at.
08:21:45 So medalist city relative to this ridge line here normalized by the dispersion in the relationship.
08:21:58 So objects or regions with very low values of this quantity have anomalously low medalist.
08:22:07 I've gotten better at saying that over the past day or so. It was hard at first.
08:22:14 So, in this galaxy has a lot of anomalous regions.
08:22:20 They consider values less than negative two, to be anonymously low.
08:22:28 So this galaxy has a quite a bit of area covered by that phenomenon and then this other example here a bit a much smaller area of the galaxy is covered by these anomalous regions.
08:22:44 They find, overall, that these occur and about 25% of all manga start forming galaxies, and in about 10% of all star forming axles. In manga.
08:23:03 And in a later study they also constrain the nitrogen, oxygen ratio in these regions and find it suggestive of disk, gas, mixed with lower middle of city material.
08:23:21 So, their argument is that these anomalous regions are caused by intermittent inflow events of lower medalists city material.
08:23:36 They can measure the approximate stellar age in these regions also using the manga data, they find that the stars and these regions tend to be about 250 million years old.
08:23:51 And so, if you treat this 25% occurrence rate as an indication of the duty cycle of this kind of event, and argue that it lasts about 215 million years.
08:24:09 Then you find. They argue in this paper that these of them's should be happening every billion years or so, for all nearby star from the galaxies. So it gives us a constraint on the amount of inflow and frequency of info, events, experienced by nearby
08:24:31 spirals.
08:24:36 Another really cool way that each to region abundances can tell us about how gas falls into galaxies is
08:24:53 from measurements of the medalist city of extra planar h two regions.
08:24:58 And there are not too many measurements of this but Chris how he has done some really cool work.
08:25:07 He has studied this extra planar age to region, above the disk about 160 parsecs above the disk of the nearby edge on galaxy and gc 4013.
08:25:25 And by looking at a mission line ratios comparing a missile nine ratios between this object, and he reaches the desk.
08:25:37 They find that it's metal content is about half that the disk.
08:25:45 And they argue that it cannot be purely objected dis gas, given that differential.
08:25:54 They also argue that because this object is relatively close to the center of this galaxy. It's unlikely, the formation of this h2o region was triggered by a minor or major merger.
08:26:13 Instead, they argued that it is consistent with he condensation picture that the formation of this region was triggered by galactic fountain material causing condensation of hot coronal material.
08:26:35 Now, they, interestingly, this implies that you know if you start with a Corona that is completely pristine this h2o region. Must have been composed of has her own material and have adapted material, which is a pretty high fraction of a coronal material
08:26:54 in the context of these compensation models and they discuss that in the paper that might be an interesting thing for us to discuss, as a group, in this paper they also hopefully, collect the other measurements of extra planar each region medalist cities.
08:27:17 There are very few.
08:27:19 They are collected here, represented here on this diagram at the right.
08:27:25 And this is height above the disk for these regions.
08:27:31 And then they're basically showing here this is the medalists at gradient.
08:27:38 They're showing here that basically all of the other h extra planner h two regions have a medalist at very similar to that of their host discs, so this is one above NGC 4013 is kind of a low medalist city outlier.
08:27:58 So that concludes what I wanted to say about what we can inferences we can draw from h2 region abundances going to try to move this zoom thing. Okay, so, um, we find from characterization of anomalously low, middle this the region's evidence for episodic
08:28:24 info events happening. Maybe once per gig a year and star forming galaxies, and also some evidence from extra planar h2o region abundance measurements of condensation triggered condensation of coronal gas
08:28:50 questions so far.
08:28:57 I will continue.
08:29:01 Now, turn to insights, we can glean from studies of each one in 21 centimeter emission.
08:29:10 Now we probably.
08:29:13 This is probably a pretty uncontroversial statement. We know the rate of inflow on to our own galaxy the best of any galaxy.
08:29:25 And in the review article that define Mary.
08:29:30 What she talked a bit about in her keynote.
08:29:34 She developed a model that she uses to calculate the inflow rate of high velocity clouds on to the Milky Way.
08:29:46 And to do that, he first of all includes the high velocity clouds with welcome string distances, only and models, the motions of these clouds with a single as a new song velocity, and a single radio velocity.
08:30:07 So that's velocity toward the galactic center.
08:30:12 And so, if you force all of these clouds to have a single as a new solid and single radio velocity, then you find the best fit values for those velocities of 77 kilometers per second, and negative 40 kilometers per second.
08:30:33 So, which is implying that as a collective these objects are falling inward, towards the disc about 40, kilometers per second.
08:30:47 Now, she's also put together a plot, showing the, the total mass that will be a created onto the Milky Way's disk, as a function of time due to the info all of these structures.
08:31:05 So here, you know she's assuming that the inflow velocity of all of these objects remains constant, as they move forward the desk.
08:31:18 And she's showing us here when each of them will hit the disk, and then mapping the total accreted mass over time on the y axis, the slope of this relation is done, the mass accretion rates, and she finds an accretion rate of less than point one solar
08:31:42 masses, per year, assuming this best fit value of the inflow velocity.
08:31:51 If she instead assumes much higher velocity of 200 kilometers per second, kind of the highest velocity allowed by the data. Then she measures, a maximal accretion rate what she called the maximal accretion rate of point for solar masses, per year.
08:32:11 These values, assume some correction, I believe, for the ionized fraction of these clouds, but to include a full ini accounting of the ionized component of these clouds, you want to multiply these numbers by two.
08:32:33 So, the maximal accretion rate onto the Milky Way, then would end up being about one solar mass per year.
08:32:44 So, that's the high velocity of clouds. Of course there are also intermediate velocity clouds. Perhaps my personal favorite kind of cloud.
08:32:56 The Milky Way intermediate velocity clouds have lower velocity so less than 100 kilometers per second.
08:33:04 They are quite dusty, they're metal rich, they are biased toward negative velocities and so are likely in falling, and they stay close to the desk and heights, less than, about two or three kilo parsecs
08:33:27 And Phil Richter in a review from a couple years ago, estimates the neutral gas accretion rate, intermediate velocity clouds. It's quite a bit lower than that in the high velocity clouds, this is just the neutral component of the I VCs but it is only
08:33:51 point, 01 2.05, solar masses, per year.
08:33:56 Alright so that's the Milky Way. We have quite good, relatively speaking, estimates up in float rate onto the Milky Way.
08:34:07 Now, but we can also in the Milky Way We have the advantage that we can look very closely at the morphology of some of these clouds.
08:34:20 And from those morphology us, we can start to see exactly what happens when a cloud falls on to the Milky Way's disk.
08:34:31 So one great example of this is the Smith cloud.
08:34:38 This is from work by Jay Lockman in 2008, the Smith cloud is a high velocity cloud.
08:34:47 It has a mass of a million solar masses, approximately, and it has a morphology. Here it is. And here is the gas in the inner Milky Way. It has a morphology that strongly suggests, is about to collide with the Milky Way's disk.
08:35:08 It's about 75 six from the galactic center.
08:35:12 Three kilo parsecs below the Galactic plane, and from its full resolved kinematics.
08:35:21 They can tell that this cloud is moving toward the plane at about 73, kilometers per second.
08:35:30 And if you make a cut along the major axis of the cloud and plot, the velocity as a function of major axis, you get this plot, over here. So this is major axis position versus HH 121 centimeter, a mission velocity.
08:35:57 And this side of the major axis or this point on the major access corresponds to these positions down here in this diagram.
08:36:08 So, the disk of the Milky Way is this black stuff here.
08:36:14 And then he's showing portions of this cloud, which are decelerating as they approach the disk so he's identified clumps that look like they were taken out of the main body of the cloud and are have slowed down as they approach the desk so we see a cloud.
08:36:38 That's breaking up as it falls into the main body of the Milky Way.
08:36:46 Another much more recent example of very high resolution.
08:36:52 Each one imaging of a high velocity cloud comes from cat Barker, who image complex, a that has a mass of about 2 million solar masses.
08:37:07 And it's kinematics indicate that it is also decelerate decelerating toward as it approaches the Milky Way's disk. So they find that the velocity of the leading part of the cloud is lower than the velocity of the trailing part of the cloud.
08:37:29 So it does seem to be decelerating as it approaches, it's moving in this direction, the Milky Way is in this direction.
08:37:41 And they make the argument that this cloud must be sitting on top of lower density coronal material. So, if the Milky Way is in this direction, then the gas over here must be much lower density than the gas in the cloud itself.
08:38:06 And so they are knew that this cloud should be developing rally Taylor instabilities on this side, and they identify several morphological features,
08:38:20 which they like into the holder rally rally Taylor globules. So that's what they're pointing out here as being features labeled RT.
08:38:35 And these.
08:38:37 And so these are, you know, these large structures that seem to be growing off the main body of the cloud. These RPS features are ground pressures strict features.
08:38:53 And then on the back side of the cloud, they identify more structures, which could arise from hundred dynamical instability instabilities, and which they like into Kelvin Helmholtz features.
08:39:09 You don't have a way to quantitatively differentiate between Calvin Helmholtz or rally Taylor features, but they identify these instabilities all across the morphology of the cloud, which I thought was really cool.
08:39:29 Okay, so that's Milky Way, each one.
08:39:37 we get a really good global estimate of the info rate on the onto the Milky Way from each one studies, and also a really detailed look at how gas looks as it flows.
08:39:52 And as it approaches the Milky Way's disk.
08:39:58 Now, let's turn to what we can learn about in the flows on to external galaxies, by looking at each one in a mission.
08:40:17 Excuse me.
08:40:19 Alright, so we have now known for quite some time from each one surveys of external galaxies that extra planar each one is really common, and that its rotation lags that the disk.
08:40:41 So this is just one demonstration of this effect. This is an H 121 centimeter emission map of NGC, 3198.
08:40:55 And this is the major axis here. This is the minor access.
08:41:03 And so, on the right hand side, morass go is showing us be each one velocity along the major axis here. So, this is direction or distance along the major access.
08:41:28 This shows the velocity profile of the gas along the major access.
08:41:30 Though portion of the profile marked in white represents the gas that is part of the disc rotating, along with the desk.
08:41:44 But the part of the mission that's shown in blue, in light and dark blue here is gas that is rotating slower than that of the desk. This is the lagging extra planar gas, and this is a really common feature of h1 studies of other spiral nearby spiral galaxies.
08:42:12 So, in this paper Marasco at all. They develop a pretty simple model for to explain these h1 rotation curves in their model, they have a regularly rotating, then disk, and then a lagging extra planar gas later.
08:42:36 And so to fit the data that you can vary the gradient in the as a new solar velocity of this layer.
08:42:48 They can vary the radial velocity so they do allow for the gas to flow toward the center or toward the minor access of the galaxy.
08:43:01 And then finally, they allow for an inward or outward flow component of this gas.
08:43:13 And so they match, they can vary these parameters match to the data, and they find that, you know, and here are the best fit parameters of that modeling, they find that the best fit parameters for the vertical velocity component tend to be 20 to 30, kilometers
08:43:40 per second. So that's kind of the most important takeaway from this plot. Do you find that, under the assumption that these extra planar layers are xe symmetric, first of all, and smooth and are well modeled by a single vertical velocity that that velocity
08:44:03 is an inflow toward the disk of 2030 kilometers per second.
08:44:10 And they in addition are able to measure the mass in those extra planar layers that mass quantity is represented here.
08:44:21 And they find that it is. Interestingly, loosely core correlated with the galaxies star formation rate.
08:44:31 So, from studies of each one in 21 centimeter emission. We get get great constraints on the inflow rate onto the Milky Way.
08:44:45 And we find from kinematic modeling, or Marasco at all, I should say, signs from kinematic modeling that neutral extra planar gas layers seem to be in flowing overall with velocities of 20 to 30, kilometers per second.
08:45:05 Okay, so that's a mission. Now, let's finally talk a little bit about absorption.
08:45:14 Do I have 15 more minutes. Is that what I have. Okay. Great.
08:45:20 Thanks.
08:45:22 Alright, so now we're zooming out a lot. We're going to start talking about much more distant galaxies, and we're going to start to have a lot less information about the motions of the gas in these galaxies.
08:45:39 We're doing a totally different experiment now. We're using the stars and the galaxies, as a background light source. We're taking their spectrum. And then we're going to be able to probe the motions of any gas along the line of sight in absorption.
08:45:58 So, gas that's flowing out of the galaxies, of course, you know, it's going to give rise to blue shifted absorption lines and.
08:46:10 By the same token, gas that's flowing back in towards these galaxies, stars going to give rise to read shifted absorption lines. So, these are read shifted absorption lines are, what we're going to be looking for.
08:46:29 Now, you already know.
08:46:31 It's really rare to see a red shifted absorption lines because of all of the outflow. That galaxies are exhibiting, but it does depend somewhat on what kinds of galaxies you're looking at.
08:46:50 So if you're just targeting Starburst galaxies, which is what many early outflow studies did, then those are really going to be dominated by outflows.
08:47:06 At the same time, you also really need to be able to have high enough Signal to Noise spectroscopy of individual galaxies in order to be able to see galaxies with info and it took us a while to be able to have that collect that kind of high quality spectrum.
08:47:30 But it has now been done and one of the first groups to do that was led by tomorrow Sato, who was analyzing quite high Signal to Noise spectroscopy.
08:47:46 Galaxy selected from the deep to redshift survey around redshift point three
08:47:55 and bees. This spectroscopy covered the sodium one D transition which probes quite cold dusty gas at temperatures less than 1000 Calvin or so.
08:48:09 So this color magnitude diagram shows the distribution of their sample.
08:48:16 You can see they have many star forming galaxies blue cloud galaxies in their sample and also quite a number of early type red sequence galaxies.
08:48:31 And the galaxies that are marked in blue here have detected outflows.
08:48:36 So you can see the predominate in the sample, the galaxy is marked in red, have inflows so this is redshift and sodium. This is detected in 31 of their 205 objects and primarily occur on the red sequence.
08:48:57 So this is a 20% detection rate.
08:49:01 And they discuss how these galaxies know they don't seem to be forming stars, but they do have signs of nuclear activity liner like line ratios are secret Lifeline ratios.
08:49:17 And so perhaps these inflows have some connection to that nuclear activity.
08:49:26 These this type of red shifted sodium absorption has also been detected in a small fraction of Sloan early type galaxies. So, this result by Sunday at all kind of backs up this earlier discovery.
08:49:42 So, this is was the first work really to identify outflows and a large sample of distant galaxies.
08:49:55 It was followed pretty quickly by study by crew get all who was studying sodium in Seaford galaxies example of nearby Seaford galaxies, with relatively low star formation rates.
08:50:12 And again, found a relatively high detection rate of red shifted, sodium, toward these galaxies of about 40%.
08:50:24 And they estimate, very rough math inflow rate on to these galaxies between one and five solar masses per year that requires a lot of assumptions about the metal this city, and ionization state of the gas, of course.
08:50:44 And there are other examples to have inflows detected and transitions that trees quick cold material such as. Oh, molecular material.
08:50:59 And this has been studied in a sample of nearby X ray selected AGM so we do see some substantial evidence of inflow toward AGM host galaxies in general.
08:51:16 When it comes to start forming galaxies, we started to make progress. Once we were able to obtain high Signal to Noise ultraviolet spectroscopy of the individual galaxies.
08:51:33 And so we were able to probe the kinematics of magnesium to and iron two absorption, which are in the near UV at 20 620 800 eggs drums and the rest string.
08:51:50 And so they're two works that made progress on this one, I lead, this was part of a survey for women's traced by these transitions in a sample of about 100 galaxies at redshift point five.
08:52:11 This diagram shows the star formation rate solar mass distribution of the target sample.
08:52:18 Who can see we detected a lot of wins the galaxies. When we detected winds are in blue, galaxies without wins or inflows are in black these black circles, and then galaxies, the six galaxies where we detected in the flow are shown in red here, so we detect
08:52:39 the detection rate of inflow of 6%.
08:52:45 Crystal Martin has also done a sensitive Kak RS study for women and galaxies at redshift one or sample was a bit bigger 200 galaxies. But again, has this pretty similar detection rate of inflow of nine out of nine out of 200 system so we have similar
08:53:10 detection rate of about 5% in both of these samples.
08:53:17 Now, we also noted that, you know, there are only six of these galaxies. We have nice HST imaging of these galaxies.
08:53:31 And we found that, you know, they tend to appear in an edge on orientation.
08:53:40 So here I'm showing the distribution of inclinations for different sub samples.
08:53:47 Galaxies with wins tend to our show with this blue mind, they tend to be more face on, whereas galaxies with inflows are shown in this red histogram, they tend to be more edge on, although of course it's only six galaxies.
08:54:07 But I do think that we are seeing here, some evidence for, you know, this blue stream.
08:54:21 And,
08:54:20 but at the same time, our failure to detect in the flow and face on galaxies, does not mean it's not there.
08:54:31 You could easily hide inflows of, you know, 100 kilometers per second in the line profiles that we observed, even for galaxies, where we detect outflows and we try to demonstrate this, in our paper.
08:54:50 For example, here's a magnesium to profile for a galaxy within inflow.
08:54:56 We say it has an inflow because it has a lot of equivalent with read word of the stomach velocity here. That's why we detect read shifted absorption in the system.
08:55:09 But here are some examples of line profiles, where we detect outflow. And you can see, they also have significant absorption. Read word of systemic velocity similar to that in the in the flow profile so these galaxies, with detected outflows could easily
08:55:31 be hosting inflows that are just a bit lower, velocity.
08:55:38 Okay.
08:55:43 So that's what we can learn by simply increasing the signal to noise of our spectroscopy, increasing our spatial resolution also helps can help quite a bit.
08:55:57 And this was done by Mark West McAdams several years ago now.
08:56:03 He took.
08:56:05 When. if you spectroscopy of em at to start forming desk and studied the age, alpha kinematics along the major axis of em at tues desk, as well as sodium one absorption kinematics along the disk.
08:56:29 And so you can see this is distance from the minor access so distance along the major access versus radial velocity. And you can see the overall rotation of the galaxy here, traced by the age, alpha and black.
08:56:48 But you can also see that there is a component of sodium absorption. That is counter rope taping this green component here, which is suggested that it's due to some recent recent accretion of that somewhat recently created clump of gas.
08:57:11 Likely along the major axis of this galaxy.
08:57:17 counter-rotating sodium. There you go.
08:57:20 Alright, so we're discovering, perhaps signs of inflow in, you know, the canonical outflow galaxy, and 82, and clearly the flows are happening at the same time.
08:57:37 Some other interesting, very recent work on this one's done.
08:57:50 And they were targeting this galaxy this edge on spiral UGC 10 205.
08:57:59 And here you can see the continuum image from there. If you observations.
08:58:06 This instrument is really interesting because it has quite high spectral resolution, in addition to spatial resolution.
08:58:29 And, in fact, they detect what appears to be an in the flowing shell of gas with a velocity of about 100 kilometers per second, positive hundred kilometers per second, all the way across their field of view.
08:58:47 And so you can see that here they're extracting data from this area, I think, if you, they see this red shifted sodium components.
08:59:04 And then here when they study this region extract this region from the if you, they uncover multiple components of sodium absorption, both out flowing and influence, so they're able to detect these things happening at the same time.
08:59:23 Some other work on this was done without any if you, it was done, led by young young, and she did the hard work of spatially resolving the gas flows across, Emma 33 by simply observing star clusters across the desk.
08:59:46 I'm 33.
08:59:48 And I wish I were not running out of time.
08:59:51 I'm so sorry I going to try to speed up here young.
08:59:57 I don't deserve this.
08:59:59 but she finds that the, the absorption probed by silicon afore is generically read shifted toward measured toward all of these sidelines and you can see that absorption those absorption profiles, down here.
09:00:22 And they model, the accretion that's exhibited by these line profiles and find a best fit accretion velocity of hundred kilometers per second or so, and they measure.
09:00:37 Quite a robust, not in flow rate of about three solar masses are geared towards this galaxy.
09:00:45 Now if we want to improve our statistics, we can turn again to the manga survey, which again, probed Eric has taken, if you spectroscopy, of a sample of 10,000 nearby galaxies, it covers sodium.
09:01:07 Sodium transition in these galaxies. And so, while it does not have spectra spectacular spatial resolution or spectral resolution. It can help to give us some sense of how frequent inflows and outflows are across the surfaces of these galaxies.
09:01:28 And so, this is analysis that I've been pursuing for a while, and I won't, I won't step through all of these details, but I'll give you the upshot of what we seem to be finding we're sensitive to flows with velocities of at least 55 kilometers per second.
09:01:52 So, that's when we think we can measure in float robustly towards the surfaces of these galaxies. And we find that you know instances of isolated inflow toward these galaxies, about 15 to 20%, of the time.
09:02:14 We also see that this these flows in the slows tend to be more frequent in more face on higher star formation rate galaxies and I'm happy to speak more about this, if people are interested.
09:02:32 So, to sum up, our results on absorption line studies we've seen quite a bit of evidence that inflows of cold gas trace by sodium are quite common in early type galaxies and Seaford AGM host galaxies in close up low ionization metals arise in five to
09:02:55 10%, at least five to 10% of star forming galaxies at redshift one.
09:03:03 Don't forget about the inflow toward em 33 that young discovered.
09:03:10 This is a star forming galaxy, but it's disk seems to be completely covered by an accreting layer spatially it resolved spectroscopy, often reveals when we have it simultaneous outflow.
09:03:35 And this is a reference I knew I wasn't going to have time to talk about this also studies by Stephanie home and crystal Martin have also been really important for showing us how gas in the flows towards galaxies along their major access.
09:03:53 So definitely check out this reference.
09:03:57 And I will end by returning to these two models. I think I'm going to just say here that I think we have evidence for all of the aspects of inflow that are predicted in these models, both condensing in the flow triggered by galactic fountain activity
09:04:20 gas that is accreted along the major access from larger scales, but I'm happy to, you know, discuss the issue. I look forward to it.
09:04:34 And that's it. Thank you.
09:04:39 Thank you very much. that was a beautiful talk.
09:04:44 And I will.
09:04:45 Yeah, it's right now.
09:04:47 four minutes after the hour.
09:04:51 And I will quickly share my screen, so that I can post some corrections.
09:05:04 I need to apologize too far as a heady for for not remembering that contribution number four and week five new results is his. And also I messed up on the panelists I mixed up Thursday and Tuesday panelists.
09:05:19 Here are the actual panelists. And how about we can reconvene.
09:05:24 Do we want to do 10 after the hour. That gives a four and a half minute breather.
09:05:31 Okay, so have a four and a half minute breather and then reconvene for the panels, and I'll ask the panelists to be perusing the slack, because there are a lot of questions and interesting points that are raised there.
09:05:45 And so when we pose questions to the panelists our primary method of doing that is through the slack.
09:05:51 So please.
09:05:54 While you're taking your break.
09:05:56 Take a look there to thank you.