 Sometimes the charm will get this. We're going live on YouTube. We're live live. Hey, welcome everyone. It's the top of the hour. Let's get started. Welcome to our July NASA night sky network webinar. It's hosting tonight from the astronomical society of the Pacific in San Francisco, California, and we are so excited to welcome our guest speaker. This is Dr. Brian Greff instead from Caltech and welcome to everyone who is joining us tonight on the live stream. We're happy to have you with us. These webinars are monthly events for members of the night sky network that we look forward to continuing the live stream online as well. We're happy to have you all here. So for information about the NASA night sky network and the astronomical society of the Pacific, check the links in the chat that Dave is going to put in there. My name is Vivian White, and Dave and I work on the night sky network. I'm going to, before I introduce our speaker tonight, here's Dave Prosper with a few announcements. Hi folks, there's actually not many announcements today. Enjoy your summer vacation. As it were, I think everyone is melting. Hopefully you're staying cool. I have a nice tip from my dad, which who spent the day in his garage you can just take some ice throw it in a pool or intern on a fan might help or just wear the ice. Anyway, just wishing y'all a happy 53rd anniversary of Apollo 11 as I saw a tweet from NASA and with Artemis one scheduled for a actually some launch dates now I'll potential August 29 launch window and then a couple of others after that every three days we'll see how that goes. A good luck with that Florida weather and late summer. Yeah, what else is happening. I'm just some we've been blaming technical problems on the solar storm there's still a little bit of an Aurora report here in there so hey good luck to any one of you in the northern areas maybe you'll get to see something tonight I won't because of storms. And what else we got up. Honestly, we're just going to see it outcome next week Vivian I look forward to seeing those of you traveling to beautiful Albuquerque New Mexico for several days of astronomy fun in the desert. Anyway, that's honestly it it's just a chill day there'll be a lot more announcements there is a ton of announcements we can't talk about them yet they'll be in the August newsletter. Everything we wanted to mention is like oh wait no embargo, oh wait not yet. So, anyway, take it away, Vivian. Thank you so much Dave. All right, for those of you joining us on zoom you can find the chat window, most of you already have in the q amp a window at the bottom edge of your zoom on if you're on desktop. Feel free to greet each other in the chat window or let us know if you're having any technical difficulties there thanks for those of you who threw in the note about the chat not working I think it should be working now. You can also always send us an email at night sky info at astro society.org. And, but if you have a question for our guest speaker tonight. Please type it into the q amp a window that helps us keep track and know if we've answered questions sometimes they get lost in the chat. All right. Could you hit record on that one Brian and then I'll get started. There we go. Welcome everyone to our July webinar of the NASA night sky network. This month we are so pleased to welcome Dr Brian Greff instead to our webinar. Dr Greff and sets a principal mission scientist on the new star mission and a research scientist at the California Institute of Technology. He grew up in DC before coming out West getting his BS in physics at Stanford University, as well as his PhD in physics at UC Santa Cruz. The new star mission as a postdoc scholar at Caltech in 2009 three whole years before the launch, and has been down in Pasadena ever since his science interest span almost nine orders of magnitude in source intensity anyway, from studying radioactive ash from supernova explosions all the way to x-ray flares from the sun. And then have a disc golfer a gamer a dad and loves exploring the night sky with his friends, even in Los Angeles that's actually how I found him. He mentioned he was an amateur astronomer and I said please come and talk with us I think everyone would love to hear from you. Welcome Dr Brian Greff instead it's really lovely to have you here tonight. Thanks for having me Vivian. All right. So let's get screen shared. All right, we looking good. Fabulous. All right. All right, well, again, thanks for having me here. As Vivian said, you know she got in touch, and I was excited to come give a talk to you guys by the way, I talked with my hands and if anyone sees my camera moving out of focus let me know. When I was growing up. I grew up in the suburbs outside of DC, and my parents got me a little, you know, four and a half inch reflector I had the full filter set and so it was good enough to go out and hit Jupiter and Saturn and you could see the moons move around Jupiter and all that kind of fun stuff. And then when I got into high school is when I sort of really started to get into astronomy. I did a couple of summers at the Naval Observatory in DC. And the science part of it was was fun, but the big part, the big fun part was I got to actually help run a bunch of the star parties that did there they have like a 12 inch refractor which is 20 feet long or something like that. The floor goes up and down you have to go in and manhandle the telescope and we got to take people up and really start to get a good appreciation for the night sky. So that was really my foundation in astronomy. I had a really great physics instructor so when I decided I want to go out to college. I knew I wanted to do physics and astronomy Stanford only has a physics department so I did get to do a lot of work with Roger Romani who's there he built a teaching observatory fully robotic. You can go drive around the sky we got images of the crab, a high redshift quasar all kinds of fun stuff. So that was sort of my my college experience and then I started building detectors so I got involved in a group with Blascapera and Roger Romani building really cold like 100 milli Kelvin single photon detectors for optical astronomy and putting them on the backside of a telescope so you can see high frequency pulsations from the crab and all kinds of fun stuff. So when I went over to grad school, I got into sort of the high energy astrophysics side of things so the physics department at Santa Cruz does the gamma ray and x-ray astronomy and the astronomy department there does all the optical stuff. So I got really involved in x-ray detectors building gamma ray instrumentation. I got we're studying gamma rays coming from lightning so we built devices to go fly around inside thunderstorms and all that kind of fun stuff. So that's when I started thinking myself as sort of an experimental astrophysicist. And that got me down to Caltech to help on Newstar which is what I'm happy to talk to you guys about today. And it was really when I started working on Newstar again that I got back into doing the astronomy side of things. We sort of it's sort of taking a break for a few years while I was doing the high energy physics side. And I'm really happy that I got back into it. And x-ray astronomy is a really fun field to be involved in because it's fairly young. We've only had really x-ray telescopes since the 1960s. And a lot of the times when you build a new instrument like Newstar you get an entirely new view on the universe. And so that's why we're here today. Newstar is one of those instruments that was sort of a complete watershed moment in high energy astrophysics. So we hit our 10-year anniversary about a month ago with first light happening about 10 years ago, three weeks ago. And I'm going to tell you guys about some of the science highlights with Newstar and sort of what an x-ray telescope is and how it might be different from things that you're used to using in your backyard or at a star party or something like that. So Newstar is a small explorer. So this used to be the smallest thing that NASA launched into space. So these things are sort of $150 million, which sounds like a lot of money for most people, but for a space mission that's very cheap. They're light, not very massive, and they're usually fairly targeted. So Newstar was, the PI is Fiona Harrison, who you might know from sharing the Decadal Survey in astronomy, which I think you heard about a few weeks ago. So Fiona's been the PI of Newstar. She worked on other high energy telescopes before that on balloons, but she's really been our fearless leader for the better part of 15 years now. So I just want to put Newstar in sort of perspective for the NASA fleet of space-based observatories. So these are either missions that NASA flew or NASA contributed to. This is from Paul Hertz, who is the outgoing director of NASA Astrophysics from one of his slides from a few years ago now. So it's slightly out of date. What I wanted to sort of point out here was that I also feel like I got very lucky because I got into this field right during a very golden age of high energy astrophysics. So this starts in the late 90s with XMM and Chandra. These are flagship caliber observatories. So Chandra from NASA, XMM from ESA, they're very complementary to each other. They both launched in 1999, which is when I was a senior in high school. And then as you move into the OTS, so the 2000s, we had Swift and Fermi, which sort of brought even the high energy gamma ray sky into sort of a modern era. And as you get into the teens, you have Newstar and NYSER, which is an extra observatory that's mounted on the space station. Now that we're getting into the 2020s, we have XB, which is a polarimeter, which just launched this year. And then early next year, we have the CRISM mission, which is a mission from JAXA. All of these observatories work together and they all give us a different perspective on what's going on in the universe. So we've really been very, very lucky that all of these missions have been flying and flying at the same time to really get a good feel for what's going on across the high energy sky. So just to put Newstar in perspective, so here is the electromagnetic spectrum. So if you are an optical observer, this looks backwards to you because the photons get lower or shorter wavelength going to the right. That's how X-ray astronomers draw things out. Energy is increased to the right. So Chandra and XMM covered that sort of soft X-ray band from a few hundred EV to 10 KEV. KEV is an X-ray astronomer unit. Visible light is a few electron volts. When you get a thousand times that, then you start to get into the X-ray regime. And typically a lot of the X-rays that are produced in the soft X-ray band are things that are coming from atomic transitions. So there's like neon when you pass a current through it, you get a particular color. You get colors associated with shocking hot material in like a supernova explosion or in the material between galaxies. And so we see very specific colors that are associated with various elements where the electrons are jumping up and down. And a lot of that occurs in the soft X-ray band and Chandra and XMM have been excellent observatories for covering that part of it. Newstar extends that horizon to higher energies. So we start at a few KEV and we go up to 80 KEV. So this is, as you can see, a much broader band pass even though it's drawn, you know, it's a log plot here. So it's drawn about the same width as what you have on Chandra and XMM. But it really extends up to the part where you're seeing the hottest and densest material in the universe. High energy electrons that are accelerated in gamma-ray bursts and supernova explosions, all of this stuff, all of that action is happening in the hard X-rays. Now there were observatories in the hard X-rays before, but Newstar was the very first hard X-ray focusing telescope. So you're sort of going from a regime where you know that there's something interesting going off in that part of the sky to it's going off at that star, or that black hole, or in that galaxy. And that's really the key new enhancement that Newstar brought to the table. So just to get some perspective on this, here's a great infographic from Wikimedia. So this shows you sort of the electromagnetic spectrum, again, backwards if you're an optical astronomer, but correct way for an X-ray astronomer, going from low to high frequencies. And this sort of gives you a scale, you know, a feel for the scope and the size of the photons that are coming in. You know, when we think about a microwave or thinking about, you know, we sort of know sort of macroscopically, you know, that that's, you know, fiddling around with water atoms. Radio waves are, you know, the size of your car kind of thing. But when you get to the ultraviolet and the X-rays, you talk about things where the wavelengths are closer to the atomic scale structure and then gamma rays for the nuclear structure. The bottom panel is the thing that's sort of, you know, is really the thing that we want to get out of the high energy X-rays. And that's showing you the temperature of an object that's mostly emitting that light in that band pass. So if we take something like the sun, it's, you know, producing a few thousand degrees, it's producing mostly infrared invisible light. If I crank up the temperature on the sun, I get a bluer star and that moves the peak of the emission up out to higher energy. And if I increase the temperature on gas even higher, I can get to the point where I actually make ultraviolet and X-ray light. So this is typically when you get to temperatures of a few million degrees, 10 million degrees, that's when you're really getting a lot of that X-ray emission to come through. And there's also all kinds of other things where you've got electrons hitting things when they're traveling at roughly the speed of light will also make X-rays and gamma rays. So we'll get into some of that a little bit later. The last thing I wanted to point out on this slide is the top panel, which is sort of the, you know, where the light actually gets through down to the surface. So what can you do from the ground? And obviously you can do infrared, you know, some infrared and some optical, well, definitely optical observing from the ground. Once again, if the ultraviolet and the X-rays, all of that radiation is actually blocked by our atmosphere, which is great. That means we don't get cooked when we're here on the surface. Similarly, when you get down into the microwaves, you can't do that from the ground. You have to go to space to do this kind of science, which is why you've got emission like New Star. When you want to open a new horizon, you really have to put something new in space. So here is New Star. So I thought it'd be useful to go through sort of the practical anatomy of an X-ray telescope, right? This doesn't look like a telescope that you're used to seeing. There's no big mirror. There's no, you know, it's not, it's hard to see where the X-rays are actually moving in this guy. So for X-ray observatories, you sort of have sort of three key components. So one is the X-ray mirrors themselves. And we'll talk a little bit about that in a minute. Like you need special mirrors and actually focus the X-rays. You can't just use a reflector like you have on the ground. You need a long focal length. X-rays don't like to get focused. You can't put them through a lens because they get completely absorbed. So you have to do something else. You need a long focal length. New Star has a 10 meter focal length. Chandra and XMM are about six meters. Most of the new observatories out there are between six and even 20 meters for things that are being proposed now. So you really need a long focal length. So these things are macroscopically big compared to what you might think of for like a rocket fairing or even the space shuttle. And down at the other side, you've got X-ray detectors. That's where we actually, you know, detect the X-rays themselves. And these are also different than what you actually would think of or you might have experienced with for an optical telescope where you've got sort of either a photograph or a CD. These are actually single photon county detectors. The X-ray sky is pretty dark. So we don't have millions of photons unless you're pointing at the sun hitting our detectors. So we use specialized technology to actually get that information out. And down there behind the detectors, that's where we actually made to the spacecraft. So just on X-ray mirrors, like I said, there's, you know, you need special mirrors. Let's see if I can get this to play. There we go. So if you just throw photons at a glass surface, they just get absorbed and scattered away. They don't do anything as far as the focusing goes. So what you need is a conical mirror like this. This is from Chandra in the Chandra Space Science Center. Here the photons come in and they have a grazing incidence deflection. So they only deflect off each of those mirror surfaces by about one degree. And that drives you to a very long focal length. So in Chandra, they had a few shells that were used to actually collect all the photons. And they focused down on their detectors, again, six meters away from where the objects are. New Star has got a few more shells than that. This is one of the enabling technologies on the left. This is one of the X-ray optics as it's being built. These things are about 35 centimeters across. They are very heavy. There is 133 shells. Each shell is made of glass. And each shell has a special material put on the surface called a multi-layer coating. This is similar to what you might have to silver a telescope mirror if you're building a telescope for optical astronomy or anti-reflective coatings for UV cameras and this kind of thing. So the multi-layer coatings are really the thing that give these mirrors their high-energy X-ray reflectivity. And there's a lot of them because you don't get very much effective area per each little segment. We've got to build up these really big optics that are very heavy to actually do the astronomy that we want to do. On the right, we have the imagers. So these were built downstairs here at Caltech. And these things are made of cabbages and tele-ride. They're a single piece of crystal. When a photon comes in or an X-ray comes in, it hits the crystal, turns it into a bunch of electrons. You can then read out all of that. Each detector is mated to a custom circuit behind it. So every pixel has its own set of readout electronics. And this lets you basically get a video stream of information coming from your detectors. Every photon that hits the detector, we know where it hit, we know when it hit, and we know what X-ray color it had. We know what the energy the photon has. So we get a video stream of information coming from these detectors. And so all of this stuff are things that you really need. A lot of people working on these missions for. So I mentioned Fiona is the PI. The detectors were made at Caltech. The optics themselves were made at Goddard in Maryland. The coatings were developed by the Danish Technical Institute, DTU in Denmark. And then our JPL manages the mission and does a lot of our media outreach now. And we also work with a wide science team who really helped make Newstar a really, really successful mission. So it really takes, you know, we say it takes a village. It took a lot more than a village to get Newstar off the ground. This is how you get off the ground. So when you've got a small mission, you sort of need to fly on a small rocket. Or at least that was true before SpaceX came along and gave us Falcon 9s. Newstar was designed in the mid-2000s and it was designed to fit in a Pegasus launcher. So the Pegasus you can sort of see on the bottom right there. This is effectively a modified cruise missile. It was originally made by Orbital Sciences. Orbital has been bought by Northrop Grumman. So they own the Pegasus now. I think we're just about done with the last Pegasus launch, although Virgin Galactic is working on a version of this called Space Launcher 1 where it launches a bunch of smallsats. Your entire observatory has to fit in the nose cone. So if you sort of see on the bottom right image, there's that little metal band. Everything north of that is the observatory. And on the left side, that sort of shows you what this thing looked like when it was all put together in Dallas, Virginia. This is the spacecraft on the bottom. You can sort of see the X-ray optics. The solar panels are wrapped around the thing, but it's only two meters. I'm about six feet tall, six three. And so this thing was just a little bit taller than I was when it actually launched. On the top right, you can see it getting placed into the fairing at Vandenberg Air Force Base. And the reason that we want... Well, first off, again, there were no small launchers at the time. But the other thing that launching from an aircraft allows you to do is it allows you to get to wherever you want to go in order to do your launch. You don't have to launch just from Vandenberg and just from the coast of Florida. You can actually go out and launch in the middle of the South Pacific, which is actually what we did on Newstar. And I'll get to why in a few minutes. If you haven't seen a Pegasus launch, they're pretty spectacular. This is not the Newstar launch. Newstar launched at four o'clock in the morning in local time. So we didn't have a chase plane. This is actually a solar observatory called Resi. You can see the Pegasus strapped to the bottom of the L-1011 as it takes off. The pilot says three, two, one, drop. And then you have the longest seven seconds of your life until the rocket ignites. There we go. And your payload goes off into space. Drop to orbital insertion was about five minutes. So it's a pretty fast launch sequence. So it was really one of those things that was, you know, we were in a big, you know, lecture hall at Caltech, you know, waiting for the drop call and everyone cheered when we, you know, we saw basically one little last picture falling out of the belly of the L-1011. And that's the last time anyone saw Newstar. Now, I told you earlier that you need long focal lengths. And then I just told you that the telescope is only two meters tall, right? So how do you square that? And the answer is a lot of amazing engineering. Newstar is a transformer. So this is what Newstar looked like. This is a simulation of what Newstar looked like after it was in space. So we don't have a GoPro floating around that shows you what the thing looks like. So the instrument went up. The solar panels deployed almost immediately because we are in low Earth orbit. So we go behind the Sun or behind the Earth quite often. So we need to keep the batteries charged. And then once we got up there, Northrop Grumman or Orbital took a few a week or so to make sure they knew how to drive the spacecraft. Everything checked out fine. That's when we actually did the deployment, which is the video that I'm going to show here. So there's the optics. There are the detectors sitting below them. There's a canister on the other side. And there's a single motor that starts driving out what we call the mast. Now this mast is each one of these bases about four inches on a side. And each of these little mandrels or these little bars here is really small. It's so small you could never deploy this on the ground with any mass on it because it would fall apart. But in space, there's not a lot of relative gravity. So you can deploy it just fine. There's a single motor down at the bottom. This whole thing took about 15, 17 minutes on the ground. I was there in the operation center. All we got, again, we don't have any cameras to show us what's happening. All we got was the current blip every time one of those little bays locked together. And we're counting to make sure we got all 17 or 33 harbor money there were. So it was a very stressful day. We've gotten through launch. We've gotten through in orbit checkout. We're actually getting the instrument deployed. And now we've actually got a fully functioning observatory. Now one thing that's kind of interesting about this configuration is you've got this mast hanging out there. And we go around the earth. So we go around the earth once every 96 minutes, which means we go in and out of daylight once every 96 minutes. And when that happens, the mast actually has a little thermal motion associated with it. And if we were only a few meters long, that wouldn't be a problem. But 10 meters is the length of a school bus. And we want to keep these things really well aligned to make sure we get not very blurry images. And so you can see on the top here, there's actually a couple little black boxes there. And those are actually laser diodes that are shining down onto the focal plane bench. There's a couple of cameras down, infrared cameras down at the bottom. And what that does is allows us to actually reconstruct the full three-dimensional emotion of the spacecraft in real time. So if we look at the stream from our detectors, we can take out any emotions associated with the mass moving. So we don't have any blurring associated with the mass moving around, even though it does move quite a bit as we go around the earth. Now X-ray observations are fairly long. We typically look at a target for half a day. So we talk about tens of kiloseconds. We don't even talk about hours. And so most, the shortest thing we do is about 20 kiloseconds long. So that's the overview of the instrument itself. This is what we get out of it. This is our first light image 10 years and three weeks ago. And the top right is sort of the conceptual picture of what we had before. So these were these non-focusing observatories that could kind of tell you, well, there was something interesting going over here. In this case, we're looking at Cygnus X-1. That's where it is now. We're looking at Cygnus X-1. That's where it is in the sky. So it's in the middle of the Cygnus constellation near Vega. So if you go out, probably right now, you can go find it in the sky. And on the bottom right is actually the focused image of what we actually were seeing with Neustar. So this is a black hole. It's a point source. That's what the point source used to look like, this big blob on the sky. And now we know, okay, you know, this is an example of what we can get. This is the galactic center. So Sagittarius A star is you probably have heard about from the event horizon telescope observations over the last couple of years. This is the galactic center. This is the big black hole in the center of the Milky Way. The top is sort of the best hard X-ray image we had before from integral of the, which is a European observatory of what the galactic center looked like. The bottom is a zoom in of that and now we're resolving all of these targets into point sources. We can see Sagittarius A star there. That's kind of the cloudy thing at the bottom. This is colored by the X-ray hardness. So these are sort of giving you a metric on how hot or cold these sources are. And there's about 500 sources in this field that, you know, we didn't have hard X-ray observations of before. As we move sort of further out, we can look at nearby galaxies. So this, I think I'm probably covering this up on the top right, but this is M31 which everyone knows and loves. This is a galaxy image in the ultraviolet of M31. And this little inset here is the new star image of all of the X-ray sources in this galaxy, in this patch of sky. So again, before you sort of know that there was a blob over there somewhere and now we can resolve all of these targets and really get a feeling for what they're doing at the hard X-rays. Now for this kind of observation we can work well with Chandra and XMM because they have a better resolution than we do. And we can sort of, we can tie together the soft and hard X-ray measurements to really get a good feeling about what these sources are. So a big blue one on the right was actually a pulsar that was discovered in this new star observation to actually be pulsing. So it was pretty cool stuff. Moving even further away, we can look at other galaxies. So this is a galaxy where we see two ultra-luminous sources in the galaxy. These are very, very luminous X-rays coming from somewhere that's not in the center of the galaxy. Most galaxies have something called an active galactic nucleus, which is a giant supermassive black hole. And again, this is something where a new star can resolve out these two sources and tell us that they're not actually coming from the center of the galaxy. I'll get back to you, Alexis, and why that's a pretty exciting new field in just a minute. So the first 10 years of New Star have been amazing. So we've had 1130 papers over 10 years. So 1130 was as of yesterday. So I just looked these all up. 50 PhD theses, it was 59. Our grad student, Sean Pike, just defended this week. So congratulations to Sean. New Star has gone through 55,000 orbits of the Earth. We've done over 3,500 science observations. So it's been incredibly productive for a very small mission. We added it up the other day. We really think we run New Star on about four or five FTEs. That's full-time equivalents. So that's a couple of part-time people, a couple of full-time people. It's a pretty tiny mission when you compare it to something that you might have like Hubble, where there's four times that many just working on public outreach. So our job is keeping New Star really, really productive and a useful resource for the community. So I'm going to talk a little bit about some of the science highlights from New Star. Obviously with 1100 papers, there's absolutely no way I can do a survey of this. So I'm going to hit some of the big watershed moments. The things where we did the observation with New Star and we say, okay, there's no other way we could actually figure out what's going on in these sources. So if any of my friends are on, there might be, if anyone's got a favorite source and I don't talk about it, my apologies. So the first thing I want to talk about is black holes. So this is what a black hole looks like, right? There's nothing there, right? It's black. So black holes, they are the cores of collapsed stars. We think they're the cores of that live in the center of many lost galaxies. We know that we've got black holes merging from Lego measurements of black hole spiraling in and making gravitational waves. But when they're not, when they're sitting there by themselves, there's absolutely nothing you can do to see them. However, once you start to feed them, you got a wealth of information about all of a lot of interesting physics about what's going on in the source. So this is an artist impression. This is from Robert Hurt, who's at IPAC, who's a fantastic artist and scientist. You probably have seen a lot of his work. You just never knew it. This is an example of what a supermassive black hole at the center of a galaxy might look like. So you've got all of this material swirling into the black hole. We call this the accretion disk. You've got the black hole there in the center, and the black hole is still black, as you can't see it. You've got a jet coming out that's producing high energy x-rays. And there's also this big torus of gas that's in the galaxy itself. And so one of the things that Newstar lets us do is peer through all of that gas and dust. For Chandra and XMM, there are some of these sources where you simply can't see them because they're shrouded in the center of these galaxies. And so Newstar hunts these black holes when we look at parts of the sky that are completely devoid of other x-ray sources. We're looking for these missing black holes that are in the centers of galaxies. Now, a lot of the accretion disk itself has a lot of interesting physics in it. And that sort of leads us to our first point here, which is there was this argument in the community for decades before Newstar launched. And it had to do with whether or not we could figure out what's going on with this black hole at the center of the galaxy. So when you have soft x-rays, which is here shown by the red and orange bands on the right, you see this emission from the accretion disk. It's hot, so it's glowing in x-rays. And then you see this emission from iron. So iron is one of the elements that has an emission line in the Newstar band at 6.5 KUV. And we see that there's some distortion in the iron line coming from these galaxies. And we didn't know what was happening here. And there were sort of two camps here. One was okay, you're seeing something really interesting, which is the top one, which is you're seeing gravitational effects distorting the iron line as it orbits in close to the black hole. And if that's true, we should have this high-energy excess. This iron line comes from reprocessing emission in the accretion disk. You get that emission comes back out as this high-energy Compton hump. On the bottom is the other option, which is that I told you there's a bunch of gas and dust around. Maybe it's just a bunch of gas and dust moving around at different velocities. And so it's absorbing that light. So it's making this thing look like it's gotten to iron line even though it's just something more prosaic. It's just the dust in the galaxy. So we went and looked and this is one of the first things New Star saw. This was NGC 1365, which is active galaxy. The blue data points are what you get from X-Mem Newton. And it had this big iron line and they couldn't tell the difference between whether or not it was gas or a gas obscuration or this gravitational distortion of the accretion of the disk. And immediately you throw down the data and you're like, okay, that was too easy. We plot the New Star data and you see this giant hump coming out at high-energy X-rays. So this was the first New Star paper came out I think in January 2013. The first paper in nature, it was fantastic. So we sort of knew immediately that it was a gravitational distortion that was causing this broad iron line down at low energies. Now that's interesting because you actually get to go then do physics with this. So black holes are sort of famously the most interesting and simple objects in the universe. They're parametrized by exactly two things for most astrophysical black holes. One is their mass and another one is their spin. Now it's not actually spin. The black hole itself isn't sitting there spinning around, but it has angular momentum which rotates space-time as you go in towards the event horizon. And when this happens it can actually distort the accretion disk. So I think people have heard about this concept of the event horizon. There's a similar where light can't get out anymore. There's a similar concept where you have the innermost stable circular orbit which is the last point where you can put a little particle and have it orbit the black hole and not fall in. And depending on the spin of the black hole that can actually move that innermostable circular orbit in and out. And when you do that you see things that you can actually in the colors that are coming from the accretion disk. So if I have a black hole that's spinning sort of anti in the direction of the accretion disk, I see where the innermostable circular orbit recede. And I get a nice sharp iron line. If I make it spin really fast then I see much more gravitational distortion. And it's an entire field of science now that just goes and uses NuSTAR with other observatories to go try to study these phenomenon. And try to get a good measurement of a large number of black hole spins. And the fundamental reason you want to do this is because that tells you about the evolution of the universe. As black holes grow up, the galaxies merge together. And if the two black holes get their mass mostly through mergers, then you expect them to have sort of low spin. If the black holes are sitting there getting most of their mass from accreting stuff, so eating material, then you expect them to have very high spin. This is actually one of the things we've been doing over the last ten years is trying to build up a large catalog of black holes to get a feeling of what their distribution of spins are. Now, this isn't a question NuSTAR is going to answer. We sort of need the next generation of telescopes. We can do this for maybe a dozen sources in the sky that are supermassive black holes. We need to do it for hundreds to really answer that question. But now we know that that's the question we need to ask because we have these observations from NuSTAR. Another thing that we can study and sort of instantly see, okay, there was something interesting there, was feedback from these massive black holes. As they're eating material, they spew out jets and they can spew out winds. So a wind is sort of like a, imagine it's sort of blowing off material from the accretion disk because there's so many X-rays coming through. And that material can move outwards at 30 or 40% of the speed of light. And when that happens, you get this thing called a P-signal profile. And these things happen right at the upper bound of what X-ray can do. So again if you look at the blue data points, if you only have those, they just kind of fall off the top of the curve and you don't know that they come back. And so once you have NuSTAR, you have all the orange data points, you have the high energy side, you know what the continuum looks like, immediately you know this is a P-signal profile and you can measure the velocity of the outflowing wind. This is important because that impacts the star formation in galaxies. We know that, you know, there are old galaxies and young galaxies and we want to know why and how are they making more or less stars? And this might be actually one of the clues to figuring that out. So there's that. And finally we can do this for black holes in our own galaxy. So these ones are more dynamic. Supermassive black holes are more or less static on the lifetimes of graduate students, with the important length scale here. Stellar mass black holes. This is where you have a black hole, maybe five, ten times the mass of our sun. They orbit big stars and they can actually accrete material and they can vary on very rapid timescales. So here's a simulation from the Goddard Space Science Visualization Studio showing the black hole sort of accretive material from its companion star. That material is flowing into an accretion disk and flowing on to the black hole. And these things are dynamic. They have orbital timescales. They've got fluctuations in the accretion disk. They go through giant outbursts. You actually get a really good chance of studying very extreme physics with material at very high density and temperatures that you just can't do on the ground. So this is again one of the things that we're dealing with new star. It's been a really fantastic journey to sort of study these things. So that's black holes. I'm going to talk now about sort of one of the black holes were sort of one of the things that we sort of knew that we wanted to study. I'm going to talk about one of the things that we didn't know was new star was going to be super exciting about. And that's ultra luminous x-ray sources. So these are sources that are in galaxies. This is M51 where they are they are not the center black hole. They're something else in the galaxy. And for a long time they were a sort of an interesting topic because we didn't we know how far away they are. So we know how bright they are. And there is sort of a global diet limit on how bright things can be in the x-rays. This is called the Eddington limit. And this is a simplified version of it. But you basically have material trying to fall into the black hole. And you have radiation that's trying to push to get out. And that's a balance condition called the Eddington limit. Where you've got a luminosity beyond which you can't get any more material in. Which means you can't get any brighter. That's the brightest thing can be. And because we know how far away these things are we know that ULXs are this unit of 10 to the 39 ergs. Now that's an interesting number because that's either sort of a 10 solar mass black hole, something 10 times the mass of our sun eating at exactly this Eddington limit or a 1000 solar mass black hole eating like 1% of the Eddington limit. When we look at supermassive black holes they're typically at a few percent of the Eddington limit or even lower like our black hole is. And so for a long time people thought okay these ultra luminous sources they are intermediate mass black holes. These 1000, 10,000 solar mass black holes they have to exist we've never been able to find them. We have supermassive black holes a million times the mass of our sun stellar mass black holes a hundred times the mass of our sun neutron stars, way lighter this thing in the middle is sort of the missing link and so there was a big discussion for a long time that okay these are that's what the ULXs are. So a supernova went off there was a supernova in M82 which is the Scar Galaxy it went off in 2014 and this was super exciting the closest type 1A supernova that had gone off in 30 years we were all in New York at one of the New York New Star Science Team meetings we were arguing about when we were going to see it in the X-rays and everyone pointed their telescopes at M82 for like a month now we didn't see anything from the supernova but this black hole has two ULXs in it and I have a friend of mine who really likes studying this the dynamics of how black holes change and so he went and looked at the time signatures of these black holes and he says okay that's weird they're pulsing one of these things was pulsing and it was pulsing so you could sort of see it like a lighthouse and you could tell that it was going around something else because you could see that the pulses change over time it was pulsing twice a second and it was orbiting something else now black holes can't pulse there's no surface there to make the pulsations happen so this had to be a neutron star and this thing was emitting light at you know a thousand times or 500 times brighter than it should have been from the Eddington limit so this is kind of what we think was happening you've got the companion star it's feeding material in it swirls into this neutron star that somehow is creating a lot of material and is beaming out this very very bright light throughout the universe this has kind of been one of those things that no one expected these things there's a good Isaac Asimov quote which is the most exciting phrase in science is never Eureka that's funny and this is definitely one of those moments studying these ultra-luminous pulsars now we found dozens of them they're ubiquitous in the galaxy they could represent all of the ULXs so these things are not solar mass black holes they're one and a half solar mass neutron stars and how they do this we don't know this is something that we're still arguing back and forth about quite a bit so the last sort of main science highlight I want to hit was how do stars explode and this is something we did design new star to go look at on the left is our sort of physics we do when I teach astronomy picture of an onion shell of what a massive star looks like as it's approaching the end of its life you've got hydrogen on the outside that's burned to helium you've got oxygen carbon, neon, magnesium all that stuff inside and then you've got the iron core stars are nuclear reactors they're nuclear engines they're fusing materials together that material releases heat and that holds up the gravity of the star once you get to iron you try to fuse iron into heavier elements iron is now that takes energy in out of the star to fuse together and so once that happens this runway process starts to occur and the star collapses down and then explodes in a supernova explosion that's the story it doesn't work if you go do your I have friends who try to blow up stars in their computers and they can't get the stars to explode so we had to, you have to put in something else you need to put in some fluctuations in order to make this happen and the reason is, you can sort of think about this like a pressure cooker as the things collapsing down all of that material is getting really really compressed in the center you're making really rich high atomic number nuclei, gold, titanium all of that good stuff that's making neutrinos that are trying to get out and it sort of hits a shock and it gets stuck on the surface this is what the top thing looks like then it's like having the pressure cooker poking a hole in the top the whole thing blows apart once you get one of these bubbles forming as it bursts out and that can be a way that you can actually get the star to explode the other way you can do it is you can have the core spin really fast this is another simulation of a stellar core where you made a neutron star in there it has high spin, high magnetic field and that's shooting material and that's the thing that blows up the star so this is sort of an open question and there is sort of a holy grail in high energy astrophysics for how to actually go figure out what's going on and that's radioactive ash so down way in the core of the star right where you sort of have the last layer that is going to get blown away and everything else is going to collapse into either a neutron star or a black hole and it's going to take titanium 44 which is an isotope of titanium that's unstable so it doesn't like to stick around for very long and it splits into scandium and then calcium and when it does that so this radioactive decay happens then you get gamma rays that come out so one at 1100 kEV and then two x-rays at 78 and 68 kEV and you have some positrons that also come out as well a new star was actually built specifically to go find where these 78 and 68 kEV photons are being produced in a supernova explosion so enter casiopeia casiopeia is one of my favorite supernova remnants I wrote the paper on new star on this so I sort of have to say that it blew up in the 1680s so it's fairly young titanium has a half-life of about 60 years so you need to look at a young nearby supernova and what we're looking at here is all different colors of x-ray light and we can decompose all of these colors to tell us what the different elements are doing so in red here this is from the chander observatory you've got iron so it tells you where the iron emission is green you've got silicon and magnesium gold is sort of the continuum x-rays that are coming out and the blue is the new emission that we have from new star so anyway we can take these images and they look beautiful and you can decompose them to those different components and say okay what looks like the other so before launch I still have a simulation on the wall in my office we assume that the titanium would look like the iron the iron is produced where the titanium is produced they should look the same we'll find out it'll be over the silicon and magnesium has this jet-like structure so it's like okay that's another option that it was actually that jet explosion we should see it going in the silicon and magnesium direction the right is what we actually saw so we were sort of this took about two and a half months of observations to actually find where all this radioactive ash is because our detectors are very sensitive to the color we can actually do a three-dimensional reconstruction of what's happening at the inside of the star and we know the radioactive titanium is not in the same place as a silicon and magnesium and it's not in the same place as the iron and it's not sort of this big uniform explosion so this was the really the first evidence that these bubbles that simulation I showed you before weren't actually happening this has to do with neutrino heating in the center of the supernova these are big blobby structures it was really a fantastic result and Newstar you know it's only because we have really good detectors we had the imaging that we can actually go localize where all of this emission was taking place so that sort of brings us to the the next 10 years of Newstar so Newstar is great because there's no consumables on board so we have we don't have any gas pointing us around we use magnetic torque rods to look around the sky we just were approved by NASA through 2025 so that's great so we NASA takes a look at all of the operating emissions every three years and we are basically entirely a guest observer facility since the prime mission ended in about 2014 there was only design to last two years and that allowed us to do all of that core science that we wanted to do the black holes, the CASA observations and ever since then we have basically been a community resource so the way high energy astrophysics works in the US is people apply to say I have this great idea to go point Newstar at something we have a time allocation committee it's a bunch of scientists who are not on the Newstar team they sit down and they sort of grade all of the proposals and then they figure out what we're going to do for the year we do this every year so we always stay very fresh we're very agile to try to address what the community actually really wants us to do we've had amateur astronomers write proposals we've had high school students write proposals that have been successful this is really one of those things that were extra astronomy is very egalitarian you can and I do do most of my work on a laptop you don't need your own telescope, you don't need a supercomputer we provide you all of the code to analyze the data is open source all of the data is free or open sources we can make it all of the data is freely available at the high energy astrophysics archive at Goddard and it's really something where our job is to make sure that all of the users and observers are doing great things with Newstar so and then we're very excited to see where we go in the next few years we're starting to do observations with JWST Christmas launching next year it's going to be a very exciting time for Newstar over the next 10 years so if you want to keep up with Newstar so newstar.caltech.edu is our main page so we post sort of little news articles there when we do image releases we do that most of that is written just by a few of us so if you see an image there it's probably done by me the JPL we use the JPL public media and outreach groups who are fantastic so there are occasionally news releases at JPL so you can go there NASA universe is the official NASA account for all of all of the observatories at Newstar science is the unofficial Newstar account where we sort of highlight a bunch of different astronomers at different career stages we just had the Newstar Newstar 10 year anniversary meeting so on Twitter you can find that at Newstar X there was some very dedicated person who not me who was going through and live tweeting the entire the entire meeting it was fantastic yeah so I think that is where I'm going to wrap up so I would love to do some Q&A I see there's a couple of Q&A topics coming in into the chat but I'm going to hand it over to Vivian to sort of see where we're going to go with that Brian that was fantastic thank you so much I learned a ton thanks for keeping us updated 10 years is kind of amazing for a relatively small scale project I'm really impressed I'm sure it doesn't seem small scale if you've been working on it for 13 years well no it's very small scale it's always you know it's one of these things where Newstar is getting cranky so we have a lot of effort going in to making sure that we we do things the right way to make sure the observatory lasts as long as possible there was a really cool question from Gregory here who is asking about computer simulation and how we know that we're not introducing bias when we're programming what we think we might see how could you just elaborate on how they do the computer simulations especially of Dying Star would be really sure so there's actually so the thing about funding about science is that the best feeling you can ever have is proving your friend wrong and so there are lots of different groups that are doing all of these simulations and so especially for the supernova explosions there are groups at a lot of the various big government labs that are doing super computer simulations and those are all they check each other and they make sure that they're starting at the same place and then they're sort of they are tweaking the physics a little bit so you're always aware that you're introducing your own observer bias especially when we're doing spectroscopy a lot of the stuff that we do with Newstar we don't see the details of what's going on we're sort of looking at a point source looking at the colors that come out and we're always starving for information so we're always aware that there's stuff that we could put into the analysis that might not be there but that's why we have all of our friends that's why we do the peer review process is to make sure that all of that gets caught before it gets it's not released as fact these are all things that people have to constantly revise really cool maybe if you want to stop sharing your screen and we'll just show you you've got those links now definitely follow them on twitter it'd be exciting to see all of the updates as they come along Cook is asking is Newstar in low earth orbit orbit and if so how do you overcome any atmospheric drag and orbital decay yeah so we are in low earth orbit and we keep our fingers crossed so Newstar has no we don't have any thrusters we basically just change our direction using magnetic pork rods so it's something that we constantly are aware of and the atmospheric drag changes over time so as the solar cycle comes and goes your atmosphere puffs up and dies down a little bit so all of these are that people are so excited about this week we really don't like because it means the atmosphere is going to puff up and slow down Newstar so that's probably the thing either running out of NASA money or coming to the atmosphere that's probably the thing that's going to bring Newstar down eventually certainly the instrument will come down at some point we're not going to be space junk but if we get through this solar cycle we've got another 10 years or so on orbit lifetime so it's something that we're really we are constantly sort of paying attention to but it also brings up a point we're also constantly paying attention to other people in space so especially with the proliferation of all of the CubeSat constellations every week we get an update oh we might get hit this week or hit that week and there's nothing we can do about it so we sort of point the narrow end of the telescope if there's ever a close approach there hasn't been for a few years but we're constantly getting updated on all of that stuff so space traffic as well as space weather is always an issue it's like having your kid out in the world just good luck and you talked about being NASA certified through 2025 how much longer do you think it might even last if barring something hitting it? yeah so the instrument itself is working fantastically well so we are because we're in this equatorial orbit so one bad side about this is I've never seen Newstar myself so if you're you know I need to go to Costa Rica or something like that you can see it fly overhead but because we're in that orbit we don't go through the radiation belts there's this point sort of off the coast of Brazil called the south Atlantic anomaly which no one's ever heard of but it basically is a point where the radiation belts dip down in the atmosphere and it's a huge radiation background and so if you fly through that a lot then you actually your parts decay and all that stuff but because we're at such a this five degree inclination orbit we can steam the top of it every couple of orbits so the instrument itself is going to you know it should work fine where it would knock on so you know but we're you know because we're a small mission everything's kind of single string so we have one version of all of these components we don't have any backups for a lot of these things but as of now like we could easily go another 10 years and that'd be fine I'm knocking on wood as well that's great is there anything you would like to see it observe that you haven't uh well so what's what's fun about astronomy right now is that we're in this era of time domain astronomy so there's a big group here at Caltech who scans the entire sky like every night in the optical and they find all of the things that go bump in the night and you know we do a lot of what we call target of opportunity observations where someone says oh you know it wasn't part of the uh the big you know planning stage where we oh we know we want to do that we can plan that out a year in advance it's like okay this thing's going off now and we have to go look at it in the next couple of days and so there's a lot of cases like that where we're gonna you know we're going to spend a lot of time chasing those things down there are things called tidal disruption events where a super massive black hole shreds a star and gets very bright in x-rays most of those things we're just waiting for the right thing to go off I would really love to see a nearby another nearby supernova and go chase those down again um but there's there's lots of you know new star has a 13 our pin it field of view it's about your pinky at your distance you know at your arm's length um so you know we don't see very much the sky at any particular time so we spend a lot of time you know slewing back and forth um but we you know there's a lot out there to go to go see um I'm not sure I could pick just one yeah and will the solar cycle we'd be able to observe that change in our own son uh yeah so so one thing I didn't put up was that you know new star does look at the sun um it's one of it's the only focusing hard x-ray mission in space right now that can look at the sun and so when I said this you know 12 orders of magnitude I know the radioactive ash we get one photon every week and uh for when we point at the sun we get 100 million photons a second you know um and so because all of the blanketing on new star we can actually really go study that so we actually do that um a couple of times a year we actually coordinate with park solar probe which you guys can hear about I think next week I can promo that for you um and so uh yeah so we can certainly see as the more sunspots are happening on the sun you see more and more flares and so we go look at the sun every once in a while to see what's going on on there and that's that gives you this uh this extra view you know we have the solar dynamics observatory but a soft x-rays or ultraviolet and so new star is really the thing that tells you if there's particle acceleration going on in a flare and kind of fun stuff and it's just to the radio emissions all of them there's solar physics is fantastic I have a lot of fun with it I love that okay maybe just one more and then we'll let you go um let's see uh Paula's asking oh about will you explain a little bit more about how you point the telescope if you don't have any thrusters on there yeah so most telescopes in low earth orbit have electromagnets so you basically have uh so wait we're a solar powered observatory right so you get the charge from the sun you can run a current through an electromagnet and that interacts with the Earth's magnetic field they're just like pushing two magnets against each other you can sort of get that get them to spin um so the Earth's magnetic field obviously isn't moving right but the uh you know when you're operating in this background magnetic field you can always point new star against that magnetic field by adjusting these electromagnets we've got three or four reaction meals on the telescope uh that point things around which is the same way that Chandra and XMM most things that are sort of you know not in cislunar space use these uh magnetic profiles to do that that is so cool I did not know that either oh well I just want to thank you so so much for joining us it's been a true pleasure um thank you all of you who have joined us online as well it's really um great to see so many people here uh with us I want to um uh thank everyone for tuning in and just stop the recording quickly Brian if you would the other Brian hi Brian Cruz thank you um I'll let all of you know that you can find this webinar along with many others on the night sky network website and the outreach resources section each of the website pages also features additional resources and activities and we'll post tonight's presentation on the night sky network youtube channel actually it should be up there uh tonight so um you can catch it right there we'd love to hear a little bit about what you've learned tonight and maybe what you'd like to hear more about in the future I'm gonna stick a link to the google form in here you want to share your thoughts um let's see one moment all right oops there you go all right um and I encourage you to join us for our next webinar on monday august 22nd same time same place almost same place on the youtube channel or here on zoom if you're a member of the night sky network when dr kelly corrick from nasa will bring us up to date on the parker solar probe um and its explorations of the near sun environment