I like to welcome our friends faculty students and alumni to the Minnesota Institute of astrophysics carlos kaufman is lecture a mosque ave interim dean of the college of science and engineering I'm pleased to such to see such a wonderful crowd here even with the snow I guess you didn't get stuck like I almost did on Sunday but it's so great to have you here I'd like to just give you a few words of introduction to the College of Science and Engineering in case it is it is new to you the college is a unique structure within public within research universities in the u.s. in combining physical sciences mathematics computer science and engineering all under the same Dean under the same College it's a tremendous the interdisciplinary and and integrative structure to to teach our students and to carry out research we have tremendous students we right now enroll about 5500 undergraduates about two 2,700 graduate students and we graduate about 1,400 undergraduates over 600 master's degrees and over 220 phd's a year within the college so it is really the one of the leading structures within the University of Minnesota a highly competitive college right now tremendous students with our incoming freshman class often actually for the past number of years having the highest average HTT scores for example at the University of Minnesota including recently in English my mistake well the kauffman is lecture is presented in memory of that beloved professor of astronomy karla scoff - whom a number of you know or I've had as a teacher he joined the University of Minnesota as a visiting lecturer in 1961 and retired as a full professor in 1978 professor Kaufman s was one of the university's greatest teachers he taught more than 26,000 students in his time at the University and he's often remembered for his very popular Star of Bethlehem lecture series professor Kaufman is enthusiasm for astronomy affected everyone who came in contact with him and I mean I've spoken to a few of you and I know that was true for you the Kaufman is lecture series brings distinguished scientists to the campus to provide public lectures on the latest hot topics particularly in astronomy and astrophysics research the College of Science and Engineering has a great tradition of showcasing exciting scientific research and discoveries and tonight's lecture is no exception I'd like to now invite my colleague Evan Stilman the director of the Minnesota Institute for Astrophysics to the stage to introduce our speaker thank you so much I if we could have just another round of applause because this is Moss's birthday we don't get often get opportunities to thank our demon but there's a special thank you much for coming on your birthday to do this normally I like to give very short introductions but I things I just want to share with you before I introduce our speaker just a couple of news things first of all if if my eyes are a little bit red it's because I just returned from an observing session with a large binocular telescope you may have seen pictures of it up here the University of Minnesota has access to the large binocular telescope through a very kind gift from Stan Hubbard and and I was observing his so my clock is completely 12 hours out of phase but but I'm here there's some news items we had Keith Oliver one of our professors was just awarded on this last weekend in Sunday at the American Physical Society meeting the Hans bethe award we were very proud of that there was also a news thing here in the slides that went by and then many of you I think may have seen because they did quite a bit of attention and news our youngest professor our most recent hire Pat Kelly has discovered a star that's a hundred times more distant than any other individual star that's been seen before and Pat's sitting right there and you can just [Applause] I I you know a lot of us are happy if it's twice or three times a pat had to go for a hundred times bigger so it's just really remarkable and in the last of these these news items I there are a number of people here in tonight's audience that have contributed to make the Kauffman s lecture possible and in particular I have Jeff Michelle here was an alumni has a PhD from the University of Minnesota in astrophysics he he works now in aerospace so he's an astrophysicist who's actually a rocket scientist normally we get those confused he is both and we're very grateful for his gift and also for the match by his employer Raytheon that is really allowed for this lecture tonight and so I'd like a round of recognition for JAXA and and by implication all those who've donated to the coffee - lecture and Carla scoff - recognition I they you know thank you very much for that all right to move on to the very brief introduction I'm just very happy when I sent the email and asked Vicki if he would give a talk she said yes and I was just thrilled because I did not know her that well but I you know knew of her work and and was very impressed professor Caspi was an undergraduate at McGill University in Montreal and then went to graduate school at Princeton University and completed a PhD thesis on pulsar timing and and many aspects of what you can do these pulsars are these remarkable neutron stars that allow very high precision observations and she has pursued a number of different paths with that way she then went on to positions at Caltech in the Jet Propulsion Laboratory and then accepted a Hubble fellowship at Massachusetts Institute of Technology before returning back to Miguel where she's been a professor ever since she's a radio astronomer by nature but has also done a lot of observing in the x-ray regime because the things that she observes demand that you do you know you use different types of telescopes to do that she's been interested in problems from localizing the neutron star to the soup / remnant and getting that coincidence which connects the two sorting out the so called pulsars ooh and understanding better these very high magnetic field phenomena called magnet ARS neutron stars are incredibly interesting phenomena and she has put a career into that and that was rewarded very recently by the Hertzberg Canada Gold Medal this is an award where the one person per year is recognized for the most distinguished in all of science and engineering in Canada and she was awarded this in 2016 and I think it's important to note that she was the first and only woman to receive this award and you know it's just an honor and a privilege to have her here the purpose of the I mean the the layout of the talk will be she has about an hour's talk prepared and then I'll come back up and I'll direct questions so you'll have plenty of time to ask questions after the tonight's talk so if if I may lead a Minnesota welcome to our latest off- lecture thank you well thank you very much it's really a tremendous honor and pleasure to be here and see so many people out to hear about the topic that is actually a bit of a departure for me so at this point in my career I've suddenly done a left turn and I'm now working on this new phenomenon called fast radio bursts and I guess the slide should appear any second but I'll just describe there we go so this is a cartoon to sort of orient you give you a little intuition of the phenomenon which is something brand-new that we've really only known about for the last decade it's a total mystery this consists of very brief short bursts as this sort of cartoon is meant to be hinting to you of radio waves that as I'm going to explain in great detail we know are coming from far far outside our galaxy but we don't know their origin this is a big pause right now in astrophysics something really brand new that we're struggling with and as I tell you about this new phenomenon it's really also an example of how how science gets done it's you're gonna see along the way as we've been trying to solve this mystery all sorts of twists and turns and surprises and really gets across what it's like to do science quite right at the forefront when you don't know you know really you literally don't know what what we had what we have on our hands what this what this puzzle is all about and you might have seen this it's gotten quite a bit of press so this was last January we were our research team was on the cover of nature where you know conveyed it very easily mystery object studying this fast radio bursts phenomenon with that kind of telescope so as Evan mentioned I'm a radio astronomer we use radio telescopes which there's an example of one look like large satellite dishes collecting radio waves from the sky and just this January we made it again onto the cover and here it's not quite as obvious what you're looking at but this is actually a portion of the Arecibo telescope in Puerto Rico the largest radio telescope in the world which also has made some important progress as you're going to hear tonight on this this mystery but but fast radio bursts they've gotten quite a bit of press not just in highfalutin science journals like nature but they've gotten press all over the place there was Washington Post article about them and new york times the magnetic secrets of mysterious verse and scientific american really all over the place it's captured the imagination of many people partly i think you hear radio and you hear you know radio signals from outer space and some people to start to think a little bit you know about oh could this be some some message or so signal and and no we don't think that's what it is at all but i think that's that's you know part of their intrigue and so I want to break this problem down for you I want you to understand what we're dealing with so first one when I say fast radio bursts let's let's be clear you're familiar with this is a radio so when you hear radio that's probably the first thing many people think of and you know this is a device that is using an antenna that's capturing radio waves at a different radio frequency so you know that the this radio here has a dial you can turn it and you can tune in to different radio stations so I know in Montreal for example we have a great classic rock station ninety seven point seven megahertz that's the that's the frequency of the radio waves for that radio station and you can there's a whole range of different radio frequencies and you find narrow regions where different stations are broadcasting we call that the their bandwidth they over a you could have tuned a little bit you know if you play with that dial you'll hear that station over a little bit of range of radio frequencies space now what are radio waves what is that device capturing well it's radio waves are of course part of the electromagnetic spectrum they're just another flavor if you like or another really color of light the light that your you're seeing me with now is what your eyes are sensitive to optical light which forms a small portion of a much broader spectrum of light the visible portion of the electromagnetic spectrum of waves that's just a this essential portion but as you change the frequencies of light in the same way that you have red is one frequency and higher frequency is blue you can go a short word it to a higher frequency even than blue to the ultraviolet and on up to x-rays and gamma-rays or you can go to lower radio frequencies down to through the infrared pass the red to the infrared to microwaves and to and so the radio waves that I'm talking about its lights just like any other kind of light it's not you know we didn't evolve with with radio eyes if we you know we could have a person with nice antennas for eyes you could see the sky you can see radio waves everywhere we have we're here but I'm this the part of the spectrum I'm talking about is the radio waves that are at very low low frequency kind of light or equivalently a long wavelength type of light and so the fast radio bursts for reasons we don't understand seem right now as far as we know to produce radio waves that are in the forms of bursts just short flashes and by short I mean just a few thousandths of a second just each one is lasts only a brief millisecond and they seem to be going on all over the sky the first one was discovered in 2007 reported in 2007 using the Parkes radio telescope and today and I'm going to show you a picture of the Parkes radio telescope it's in Australia today we know of about 30 of these events have been detected a total of 30 events but in spite of only having seen about 30 of these we actually think they're extremely common so that we believe these short bursts are happening something like a thousand per day if you look over the full sky so if you could look everywhere which is hard with the telescope usually you're pointing one direction but we from the amount of sky any one telescope can see we can extrapolate and infer that it's a very very common phenomenon and as I said their origin is is totally unknown we can definitely state they're not microwave ovens and if if that sounds bizarre to you you'll understand in a minute why I say that so as I said that the first one was detected using the Parkes radio telescope and here's a picture of the Parkes radio telescope in a New South Wales Australia this this radio telescope is an aperture 64 meters and just for scale that's a three-story building underneath it and I actually did a lot of my PhD work and sitting in that little building very it's a lot of fun to to sit there and feel the telescope move or the whole building shakes when if you do it just right you have to get it just right in and just there's a road down here if you just keep going down the road there's a visitor's quarters where you as an astronomer you live there there's little rooms where you sleep and there's a kitchen with a fridge and food where you can eat and that's how as astronomers we live this is a popular press photo of the Parkes telescope you know detecting a fast radio bursts so this is how yeah you know if you if you wonder what one of these things looks like you can't see it so this this is not a this is a silly cartoon they're just trying to show you that there are waves coming from a point on the sky that hit the telescope it but that should not be the picture that's not how we see them we can't see radio waves unfortunately so you might wonder well how do you know what they what does it look like to you with a radio telescope so it looks this is how it looks to us we collect the data from the antenna that's at the focus of the dish and we digitize it and amplify it and record it on a computer and so what we really see is if you look just at this little inset here normally we just see noise coming from the sky nothing interesting and you see this big blip where the intensity of the radio waves suddenly got very very large and then it disappeared and we're back to noise and it doesn't come back okay that's that's a fast radio birth now the rest of this plot is a little more complicated I do want to explain it to you in detail I want you to understand this is very important so what we have plotted here is just like the radio dial this is the range of radio frequencies that our antenna is sensitive to and you see we have a large large bandwidth and in fact you can see there's there's this line going across here this is toy on the x-axis here you can see a line that's actually a radio station right there so that's what a radio station looks like to a radio astronomer it looks like at a fixed frequency allow a large signal and we filter that out because that's annoying we don't want the radio station in there we want the sky and it's this dark band that you see sweeping sweeping through the band going arriving first so this is time so the signal from the sky arrives first at very high radio frequency and then comes as at longer at the lower radio frequencies it takes more time to arrive it sweeps through this band and that's that's a really important effect okay and I want to explain that effect to you why it does this why it doesn't just derive at all radio frequencies at the sky at the same time it it sweeps through the band so I'm going to explain to you why we believe this does this but first I just want to explain to you why we call it the Lorimer burst it's after the astronomer who first noticed a duncan Lorimar a good friend and there you can see Duncan with the Parkes telescope in the background now the reason I want you to understand this sweep so badly the reason I'm going to dwell on and explain it in more detail is that it's the reason we believe this these these fast radio bursts are coming from far far outside our galaxy so you say well how do you know these flashes are coming from outside the Milky Way galaxy how do you even know they're coming from outside our solar system or maybe they're even in our atmosphere how do you know anything about you see a flash what are you how do you know what that is and we're asserting not only is it from far outside the Milky Way galaxy we think it's from the farthest reaches of the observable universe and so why is that at first let's be sure everybody is on the same page about the scale of the universe so so this is of course a cartoon of our solar system you're familiar with this there's the Sun there's the earth you know the planets they're not really on rings I don't know why they always draw those rings there it's kind of annoying but of course we are part of a large galaxy and a large galaxy this is this is this is not our galaxy you might think I would show you a picture of our Milky Way galaxy but but I can't do that because we're in it so it's very hard to take a photo of the outside of your house if you're standing inside of it so if anybody ever shows you a picture of a galaxy and say it's a Milky Way safety I can't be the Milky Way you'd have to zoom out and that's impossible but this is a galaxy that's a lot like our Milky Way galaxy we believe so if you could zoom out and take a picture that's what it would look like and for scale you are here so the entire solar system is a speck way smaller than the dot that I've drawn there my you know something that would be that on this scale is infinitesimally small you can't even see it but the point is that it's on the outskirts in a inner region in outskirts of a spiral galaxy that's that's roughly where we sit and and by the way if what does what does our galaxy look like from the inside this is a lovely view of the center of our galaxy seen from New Zealand actually from that it turns out that the center of our galaxy is in the southern hemisphere it's hard hard to see this and and really what we see is we're looking through the disk of the galaxy and you see a lot of stuff in the way actually it's a lot of dust in our galaxy that obscures the bright light from the center of the galaxy so this is what the disk of the galaxy looks like looking right into the into the center of our galaxy that's how we see our galaxy but just to come back to this point about the scale when I say fast radio bursts come from the farthest reaches of the universe what do I mean so again here's if this is the earth and it's a little hard to see but I'm gonna walk you through this if this is the the solar system and you can see there's a little dot there I hope you can see it it's red that's that's the earth and the scale of the solar system and now if you zoom out of the solar system to the nearest stellar neighborhood just the stars that are closest to us the solar system is now just spec okay and if you zoom out of the nearest stellar neighborhood to the scale of the Milky Way galaxy and again we're a speck on the edge of the galaxy but now if you zoom out of the Milky Way galaxy so that we're in the nearest local group of galaxies so now each smudge here is a galaxy and the Milky Way is over here you can see there's a whole bunch of galaxies now and if you zoom out of that you get into the Virgo so we call it a cluster of galaxies so this is now the the entire local galactic group is now just a speck and the scale of the super cluster galaxies and this this super cluster of galaxies is actually part of even is now a speck in this scale we've now assumed out so that the whole super clusters is too speck and if you zoom out to the farthest saw of the scales in the universe the universe each of these is each little smudge here is actually a super cluster of galaxies and ours is just now a red speck and this is the scale on which we think fast radio bursts are coming okay so in now in that now that's that's a quite quite a claim and you should always you know in science you don't believe what you hear you have to you have to how do you know this how can you make that assertion how can you be so sure that it's coming from so far away so let me come back to this and this is where the sweep how this that the radio signal from the bursts sweeps through the radio band that we were sensitive to the telescope this is why how it matters now we call that sweep dispersion and dispersion you're actually familiar with it a very similar phenomenon is what is what happens when you shine a light of a beam of white light through a prism white light is actually composed of many colors the colors of the rainbow and what a prism does is it geometrically splits up it the lightweight the light raised by different amounts depending on their frequency so red bends a little bit differently from blue so that prism breaks up the white light into many colors of the rainbow and in fact that's the reason for the rainbow that sunlight which is which is composed of many colors gets dispersed by water droplets in the atmosphere and if the alignment is just correct you the water droplets act like little prisms and that's why we end up seeing the sunlight spread out into its constituent colors and so but what you might not know about dispersion so you're probably familiar with this but what you might not know about dispersion is that it also causes a little bit of some delay in the signals so that red not only does it get bent differently from blue but it slows down a little bit in the in the material and it slows down by a different amount than blue slows down so that if you could send a pulse of white light you would see that the blue comes out a little faster than the red in addition to getting bent by a different amount and that means that the speed the speed of the different colors is a little bit different in the prison and you might say well wait a minute a very famous gentleman who you probably know he said the weight of the speed of light and that's this that that's it you probably know you the famous equation e equals MC squared where C is the speed of light that's a constant what are you telling me it's not just a good idea it's the law like travels at the speed of light how can you tell me otherwise well that's true but only in a vacuum when light is traveling through a material different frequencies will travel at different speeds now you might say well you're talking about radio waves going through space is a space of acumen why doesn't this work in space and and space is not a vacuum space is made of there there there is material in space even though there's not a lot of it but there are atoms in space and in fact ray oh waves in particular are dispersed by free electrons so atoms can lose electrons on this cute little little cartoon and where and so there are both atoms in interstellar space and there are free electrons in interstellar space and free electrons to radio waves are like a prism to white light free electrons disperse radio waves now let me explain a little bit more so this noise I'm suddenly suddenly out of nowhere I'm showing you a contour plot this is a contour plot of the relief of some mountainous regions in I believe in Maine in the state of Maine and why am i showing you this I'm just reminding you what a contour plot is a contour plot here are these these are lines of constant altitude so if there's a peak over here you can see the lines are labeled by their altitude relative to sea level or something like that and any line here you know if you walk along that line it's gonna be at a constant altitude you won't be walking down or or up if you're on if you're following one of these lines that's what a contour plot is so just keep that in mind for a moment hold that thought and let's come back to the not Milky Way galaxy okay so this is a spiral galaxy just like the Milky Way a picture of it and this is what our best model is for actually for our Milky Way there's a computer model where the color here is showing you the distribution what we believe is the distribution of free electrons in our galaxy there's lots of atoms there too but atoms sometimes lose electrons and we have ways of measuring the free electron content in our galaxy and so if you can just show where are these free electrons are it sort of models the structure it goes along with the structure you see spiral arms there's lots of free electrons and spiral arms is less in between there's a lot in the center of the galaxy we think there might be a hole in the center of the galaxy and free electrons we're not actually too sure about that but the what is that we have developed a model which you can also express as as a contour plot of the distribution of free electrons in our galaxy and so now we're looking down the this is where the center of our galaxy would be and you see the spiral arms are sort of in a in a kind of funny shape there and and the earth the solar system is up here where I'm showing you here and these lines are lines of constant total numbers of free electrons and so in any direction in our galaxy we know roughly speaking for any distance how many free electrons there are and what the line of constant free electron density is and so I'm telling I'm telling you this for a very important reason the reason is that we know where the free electrons are in our galaxy and in particular we know for any direction what the maximum number of free electrons are in our galaxy our galaxy you've run out of material after a while and we know in any direction from these kind of maps how many free electrons there can possibly be in that direction and this is crucial so this so now here's a cartoon cute cartoon what you're going to see is a fast radio bursts and it's going to be shown as a burst of white light that then travels through the earth and you're meant to imagine that there's lots of free electrons here that are going to disperse it like a prism so the idea is go ahead there there's your FRB it's white but as it travels the the colors travel at different speeds and the blue arrives first at earth compared to the red so it's acting like a prism except for radio waves and so there you go again you can see it traveling and spreading out that's very important it spreads out as it travels right there and so just to drive this home one last time the different color radio waves travel at different speeds in free electrons which we call plasma interstellar space is not a vacuum these free electrons act as a prism for radio waves so that if it's emitted as a single burst at the source it sweeps through the frequency band in this and like an ax like this is spreading out all the frequencies into different colors and this effect will wash out short signals if you don't correct for it because over a short amount of time they all arrive at different times and you and so what we do is in software we correct for the using a computer we correct for this delay for this sweep and here's the point okay here's why we think fast radio bursts are coming from the furthest regions of the universe here's the sweep from the delay from the amount of this dispersion we can measure the number of free electrons that have to be between us and the source okay and that number in crazy don't worry about the unit so the number is 375 and crazy astronomy units don't worry about that but from the maps of the galaxy that we know and have calibrated using galactic sources we know what the maximum in that direction is for the Lorimer burst and that maximum is 25 so we know that there's no way our galaxy is anywhere near the number of free electrons you need to get the sweep of that short fruit of that fast radio bursts and not only not just by a little bit by over a factor of 10 we're off so it cannot be our galaxy that's doing this and so that observation alone when lormer and his colleagues in Australia with the Parkes telescope first measured this dispersion and they knew what direction it was and they saw they were they were astonished they said how can this be and it had to be extra galactic and not just extra galactic very extra galactic it has to be way outside our galaxy and that tells told them immediately something else really important because we know of sources in our galaxy that do something like this but if this fast radio bursts is going to be far outside our galaxy then it has to be extremely bright for us to be able to detect it at such a large distance so it must be it's if it's so far away it has to be incredibly bright and this gave them pause this is some sort of new phenomenon this is it has to be you know a thousand to a million times brighter than any radio bursting object that we know of or have ever studied before but they didn't know what it was and initially back in 2007 2008 they were puzzling is this real is this not real there was a strange other phenomenon that they measured at Parkes around the same time this is an example of it they called them parrot tones I don't know why they call them parrot ons but the point is that they looked a lot like most of the fast radio bursts they were seeing the standard you know sweep through the radio band but it looked a little strange a little clumpy you know sort of spread out in some places not present in other places it looked a little different and they thought what is this wha and and it turned out some of them looked beautiful like the standard Lorimer bursts and some of them looked strange and it bothered them that there seem to be two classes and when you don't really know what's going on you try to plot things in different ways and so this is what they did is they plotted all the regular ones that had smooth frequency sweeps they plotted them versus time of day in Australian local time and those are the dark gray ones and in the weird ones the parrot ons they plotted in light gray and they notice something in that the strange ones by far seem to prefer noon they'd like to come at lunchtime so parrot ons occurred most often at lunchtime and there's a highly technical term for this sort of phenomenon it's called suspicious because you know why should some astronomical phenomenon happen to know about the eating habits of humans particularly New South Wales Australia that doesn't make any sense and what they realized is you know I told you all about where I spent my PhD thesis the road down there the Visitor Centre and the kitchen and the microwave oven in the kitchen they got suspicious because the microwave oven in the kitchen at the Parkes telescope is not shielded in any way and it turns out that Mike the microwave oven in the park's kitchen will emit para tones but not just any old time you have to be very impatient with your lunch and you have to you know you'd set the microwave oven on and then you open they you have to open it before it shuts itself off so if to open it while it's still running and of course it shuts itself off but it takes a few milliseconds it turns out for it to shut itself off and so they had a PhD student stand there with you know with paper make time okay open it open close right in it and and it turned out every time she did that it produced a parrot on in the radio telescope but it was confusing at first because the telescope also had to be oriented toward the visitors center so it had to be in that general direction and someone had to be impatient with their lunch and that made the parrot ons and I'll show you here so the months the Monthly Notices of the Royal Astronomical Society is one of the most prestigious Astrophysical journals there is and I want to draw your attention to this paper identifying the sorts of parrot ons at the Parkes radio telescope I don't know if you can read it I'll read it for you this section of the abstract of the paper it says subsequent tests revealed that a parrot on can be generated at 1.4 gigahertz the the frequency that they were looking at when a microwave oven door is open prematurely and the telescope is at an appropriate relative angle and you know you might wonder you know did this just you know were they embarrassed was it is this a disaster for astronomy and just the opposite so to me this is wonderful this is an example of science at work we don't understand something and we figure it out and if we've gotten something wrong we announce it publicly and we explain it to everybody in great detail I mean they have a chart in there of open-close open-close you know and then showing that it's all in there you want to see it and this is how science works this is very surprising to them and but I think the most important aspect is what they said at the end this and other distinct observational differences between parrot ons and other FR bees that arrived at all at random times show that FR bees are excellent candidates for genuine extra galactic transients and it was really understanding that some of them were not real and and seeing that most of them were a large fraction of them were and now that phenomenon has been seen at other telescopes that don't have microwave ovens that we believe fr bees are real and as I explained from their dispersions at cosmological that is at very large distances and so you know what our fr bees so people ask me so what do you work on and I usually answer like I don't know you know there currently there are more theories published in the literature about what these events are then there are actual events that have been discovered you know it's something making a large burst so huge bursts of energy so you think an exploding star of some kind supernovae perhaps perhaps colliding stars you know that we can have neutron stars as you heard in the introduction these are very compact objects if you smash them together you can get some really bright explosion maybe it's two neutron stars colliding or or you want to get maybe a neutron star in a black hole to collide you know or comets asteroids impacting neutral stars all of these are in the published literature trying to explain the how bright fast radio bursts are and how common they are but the answer is we we really really don't know and you know but we recently so recently we've had a few more clues and I want to share them with you and that's going to take us to I promised you I would talk a little bit about the Arecibo Observatory in Puerto Rico so this is now a an aerial view this is three hundred meters across three hundred meters across that's I don't know it was a three football fields across I guess this here is a lovely three-story Visitors Center with a beautiful Museum a Science Museum they bring Puerto Rican school kids they are all the time you can see a parking lot down here this here is a is a catwalk so you can scientists and engineers can walk walk along this and go walk up on this enormous feat structure where you could easily have you know 100 people roaming around up out there this is a picture of me and a couple of my colleagues standing at the peak top of the catwalk where I don't know why we bother with with these hard hats like if we fell I think there's no point I don't know and if you do zoom in you will see our knuckles are white because it is really scary up there we but it's also a lovely view and you might recognize this telescope from the major J and the major motion-picture James Bond Goldeneye where they actually pretended that this dish was in Cuba and not in Puerto Rico it's really in Puerto Rico and I'll just tell you a brief story that Pierce Brosnan who was James Bond in this movie there's a great scene in Goldeneye if you watch it where he's running along this catwalk and but it's not really him it's his stunt double because he was too scared and so I'm very proud and to have done something that James Bond was too scared to do but in any case let me show you the first fast radio bursts that was found not at the Parkes telescope in Australia this is FRB we call it 12 1102 we named them by the dates on which they arrived at earth so it's the same picture that I've shown you many times this is now radio frequency and time and you can see it's sweeping through the band it curiously it sort of disappears at the lower regions of the band we're actually a little less sensitive there so we were not too surprised and this is when you correct in software you you align all of this up and you sum it up and you get a nice nice burst and you see the the this fast radio bursts last last a couple couple of milliseconds and this was the first like I said the first FRB that was found at an observatory other than parks which our parks colleagues were delighted because they were still worried what if it's something else at the observatory they haven't thought of but there's a completely different software different team and we looked at this very carefully and convinced ourselves very much that had to be real then we detected it at other radio telescopes and then an amazing thing happened we decided to keep observing this region of the sky just in case it came back and parks have been observing all their fr bees and and nothing had ever come back so I was a little dubious about this whole project but you know ok I'll give it to a grad student to look at those data even though I'm thinking he's not gonna find anything but that was not the case so the Arecibo fast radio bursts decided to repeat and this was a big shock to us so this is the original the first verse that we detected in 1212 1102 it of the 2nd of December 2012 and then many many months later and many observing sessions later we had observed this many times never seen anything one day it decided to admit another 10 births these are all on the same day we were shocked you can see summer really weak and so now they've all been corrected for the dispersion they're all at the exact same dispersion measure this is the range of the sweep is exactly the same so we know it's the same source and it these two bursts the one where it's super bright and then the one where it's a little less bright these are within something less than a minute of each other and this was we were blown away so this was a shock and it was actually my PhD student at McGill Paul Schultz who made the discovery and he you know he sent out an email saying I think I might have found something interesting and we were like ah we couldn't believe it and we got lots of press over this so you could see CBC News and Canada the Washington Post and all sorts of different places wrote about it and it was immediately they just like just 10 verse that throws away half the models that throws away half the theories it can't be you know neutron stars Catco in 10 times in an hour it doesn't work that way it can't be a supernova explosion because it was month later I mean immediately we eliminated with one observation we eliminated a whole class of models and that was very gratifying but the importance of this repeating event was there's another it's as important because it could rule out models but it was also important for another reason and let me explain to you what that other reason is now we have what we call a Sky localization problem with radio telescopes so here's a region of the sky when the Parkes radio telescope sees a fast radio bursts it knows roughly where in the sky it came from but this is the sort of scale of the the size of the uncertainty region so Parkes has a pretty blurry vision and all it can tell us is that it's in a region roughly this size it's it's something like a little less than the full moon okay and if you look with an optical telescope if you go and you want to know is there a galaxy there did it come from some galaxies we know it's not ours we know it's from far outside our galaxy but maybe it's coming from another galaxy you'd expect that that's where most stars are in galaxies but the problem is what parks can tell you is the region of sky and there's a thousand galaxies there so you can't know which galaxy it's coming from it's a it's a prominent and as you go to larger radio telescopes you actually narrow in a little better so Arecibo its uncertainty region is smaller but still there's a hundred galaxies there and you can't know but with the repeat once you have a repeater you have a hope you have a hope you can go to a different kind of radio tell oh yeah so this is a different kind of radio telescope called the Very Large Array it's an interferometer I'm gonna explain what that is in a moment and there's a great one in New Mexico so if you can look with an interferometer you can localize to a tiny region of the sky and you can look and see is there a galaxy there and so once we knew we had a repeater we could go to the people at the VLA here's the VLA and we could say hey can we borrow your telescope and can we have a look at this region of the sky and see if there's if there's a faster we're the fast radio bursts is coming we know it's bursting a lot can we look and they were very excited because this is a very hot topic and they gave us time and we looked and the source didn't do anything and they gave us a lot they gave us quite a bit of time and it's time on this kind of telescope on an interferometer like the VLA is is very precious it's everybody wants to use interferometer and makes fantastic images and you know to just say coming up sometime and they said ok here they gave us some time we saw nothing we came back and they gave us exhibits 10 hours we saw nothing on that VLA we think we went back the following month that give us 40 hours they said let's really get this the source did not cooperate no burrs it's very aggravating and you know they're going excuse me we need our telescope back and we're saying just just give us a little while longer we're sure and they said okay you can have another 10 hours and fortunately in those and in the test as we were setting up the observations just test while we were testing our configuration the source went boom it started to be active again just in that last observing session and for arcane reason so the the circles here you're seeing are the regions we have are the uncertainty regions from the Arecibo radio telescope and during our observation it looks like a star in the observation here but that is the signal as seen by the interferometer we know we can localize it exactly to that tiny little point we were able to measure with the VLA independently the same sweep the same dispersion measure the same amount of free electrons we know it's exactly the same source and that was very exciting because that could that allowed us to pinpoint the location very precisely and then the next step once we had that we could we want to them is there a galaxy there so then we have to go to our friends yeah so here we caught and in fact it in just burst once we caught nine bursts with the VLA and that observing session very gratifying all of the same dispersion measure all at the exact same position we know we had nailed it we got a precise sky position and that allowed us to then go and beg for time at an optical telescope this is how the chain events then you go to your friends at the optical telescope this was the Gemini telescope in Hawaii and we said hey can we borrow your telescope we finally got a position for a fast radio bursts and they said sure and here we didn't have to rely on the source bursting we just want to see if this galaxy of that position and sure enough this is the optical image and I have to say we were a little underwhelmed we were we were expecting a nice honking lovely spiral galaxy or something interesting and instead it's this puny little nothing galaxy it's incredibly faint they call it a dwarf galaxy and here's where they I oh my goodness there's all sorts of different types of galaxies who knew is it's in a very very tiny little galaxy and this is work done by McGill postdoc shri harsh Tendulkar but what we could learn from that tiny little nothing galaxy this dwarf galaxy is this we have ways using spectroscopy awesome optical scheduled spectroscopy of determining the distance and we could this is the first time that independent of the dispersion argument and the free electrons the all that arguments about the galaxy and the contour plot all that which led us to believe they had to be far away finally we could check we could check and indeed this galaxy is is at a cosmological distance it is extremely far away and we were that was very gratifying and this generated all sorts of press so you know USA Today LA Times Fox as everybody was reporting on this the monster bursts of radio waves the Rosen tiny galaxy surprise it was a surprise we were really shocked the New York Times did a little graphic where the famous science writer Dennis Overby wrote radio bursts traced to faraway galaxies but caller is probably ordinary physics now I have to admit I didn't like that too much I feel like I'd like to to bring an FRB to his home late at night in the dark and explode it and see how ordinary he finds that but on the other hand curiously the New York Post scientists a radio signals from deep space could be aliens Thanks but we never said that why do we didn't say that interesting any case where do we stand we know at least one FRB repeats we have so that rules out exploding or colliding stars at least for that source and we were able to confirm that they are indeed at cosmological distances or at least this source is definitely as far away as we had inferred from the dispersion but what we still don't know is do all fast radio bursts repeat we don't know is this the it's probably not the only one that repeats are there two classes do some repeat and others don't we our Parks colleagues keep looking nobody has seen another repeat from any other source what is the bursting source we don't know what it is and why is it in that tiny galaxy and so this is what we don't know the answers these questions we're working on it and so how do you go about solving this you know you and and I really wonder like I'm really curious what these things are and so how do you solve a problem like this it's very hard when you have a regular radio telescope and you can only look at a tiny region of the sky you know if it's a transient source population where it's going off and you don't know where the next one is going to be the only way to solve that is to look everywhere at the same time which is of course not very easy especially when you're looking for these short events and you have to correct for this dispersion and it's very hard but the only way to solve this problem is to find more and so for the last part of the talk I want to very quickly tell you about a new telescope that we're building in Canada called chyme the Canadian hydrogen intensity mapping experiment this is in Penticton British Columbia and this is a picture of it it exists and that might not look like a radio telescope to you but but it is so this is a different geom geometry for radio telescope first of all just the dimensions here and these are four cylinders or four half pipes four half pipes that are the length here is a hundred meters a hundred meters by 20 meters this is 80 meters by a hundred meters that's the area in Canadian units of five hockey arenas I have to I hate doing that to Canada we're not just about hockey okay we're all anyway but I do love I'm a big big Montreal Canadiens fan any case so it's 420 meter by 100 meters cylinders there they have no there's no moving parts here you can't steer this thing it it sees exactly what is overhead these are oriented exactly north-south so the sky rotates overhead as the Earth turns so we get to see only what's overhead it's operating at a frequency range of 400 to 800 megahertz and what's happening here the way this works is that a cylinder unless so a dish focuses to a point so at Arecibo or at parks you put an antenna at the focus of the dish a cylinder on the other hand focuses to a line and so we have populated these focal lines each each cylinder has 256 antennas hanging from it and these are all each each of these there's each antenna has two polarizations at two two cables coming out and they're all going into effectively a massive supercomputer that is collecting all of the data from all of these thousand 24 antennas simultaneously and the input data rate that we're talking about here is 13 tera bit that should be terabits per second so the total amount of data that's being collected from all these antennas is equivalent roughly speaking to the world's entire entire cellular network and all the supercomputing some of it is sitting in houses that are you can't quite see that are under the dishes but these are also sitting in these specially outfitted shipping containers that are on the side here is massive supercomputing going on crunching all the data from these antennas this is a project that is a collaboration between McGill University University save Toronto and University of British Columbia and the original design here for the South scope is actually driven by a totally different project it's meant to do cosmology and study hydrogen gas in the distant universe and it's my cosmologists colleagues who came up with this interesting design for a telescope and later we realized this would be great for studying fast radio Bertha and let me explain explain why and just first a little bit more about the telescope they're just for scale you can see part of the team standing in the in the in the axis of the cylinder and here is just to give you a scale of the region around there in Penticton near Penticton British Columbia this is a drone so it's a drone view of the cylinders you can see here in front the shipping containers and the the four four axes from above there the the attitude is slightly changed for the drone I was really hoping that the person videoing it would come and then AO swoop down the axes like you know star was it doesn't he wasn't that silly that would be really dangerous you didn't want to do that but you can get a feeling for the scale of of the telescope from this this lovely video but now why is this really good for transients so let me be clear here if this is the Parkes telescope the Parkes telescope sees a tiny region of the sky and for a transient source population you you have to get lucky I mean they get they get they find a few Perce they found 30 in the last decade or 20 not you know something like 29 a couple dozen in the last decade but they miss most of the ones in the sky because they have a tiny field of view on the other hand when you have a cylinder the cylinder focuses the light from a much larger region of the sky from a whole line on the sky and so compare the field of view of the Parkes telescope to the chyme telescope and what you see is you know it's it's it's a no-brainer if you want to study a transient population you need a large field you and so the way this works is the sky rotates overhead and we can see a larger fraction of sky we still don't see the full sky but we'd see a much larger fraction of the sky with time and so we're gonna catch a lot more fast radio bursts and we think we can catch a few to a few dozen per day using chime and that will allow us you know if you have thirty in the last decade once we turn this on in the first week or two we'll have as many as we've had in the last decade and that's why we're so excited about chime not just for the wonderful cosmology that it's going to do but also for the transient project we had our first light ceremony in September 2017 at chime with our Canadian minister of science Kirsty Kirsty Duncan she she came out to Penticton and and what you could see some of the antennas there she wasted the last set of antennas and snapped it into place and then chime magically turned on we this is this is first light data so this is some data from chime and this is now showing you you might see that that doesn't look like much data there Vicki what are you talking about and well this is time on the x-axis and this is now dispersion on the y-axis dispersion emission and actually what you can see if you look really carefully down there at really low dispersion measures you can see pulses and that's a pulsar in our galaxy so at a very low dispersion measure because it's in our galaxy and you can see little pulses of radio waves that's a sort of signal we hope to be able to see at much higher dispersion measure albeit they don't seem to repeat very often I'll skip that I just want to say that the chyme telescope project this is really built and and and being commissioned now mainly by students students and postdocs this is we have a few engineers working on the project but it's very much a student project we're it's a very large complex instrument but you can see here this is PhD student Ziggy polenta's from from McGill we he and I spent two weeks plugging in cables basically and you can see from UBC this is mei-ling dang who who designed the different types of antennas and you can see also from UBC project manager Montana Miri and all sorts of people who are working on this project together and we're very excited it's it we're not quite there we haven't yet detected fast radio bursts but we're commissioning the telescope right now and we're quite excited because in nature in January they wrote what are the big top science things to expect in 2018 and frightening Lee they put the chyme telescope as one of the first items and that's like no pressure on us none whatsoever but in any case I say to chime fast radio first project stay tuned and in a couple of years we might actually have have learned more and understood a lot more about these fast radio bursts and I'll stop there and thank our sources of funding in Canada for this for this project and I thank you very much for your attention so as promised the key we'll take questions from the audience we have there should be microphones there's a microphone over there where's this in this microphone major so just raise your hand and a microphone will come to you and then you can ask the question there's really a couple of front here I can direct if their microphones don't see you how far how far was that source for the repeating FRB I don't think you said I didn't say they're never a bit so it's a Giga parsec so it's something like 3 billion light years billion thank you far yeah so it's an appreciable fraction of the sizes of the universe and for those who know about these things as a redshift 2.2 I think that was a girl about chine was it really a circle slash cylinder was it a parabola or hyperbola yeah that's a great question so it's in one it's a long line in one direction and the shape in this direction is like a parabola yeah cylindrical paraboloid another question about chime you said you're downloading data at sixteen terabits per second yeah if there is thirteen terabits per second yes how are you storing the data and like how long is it being stored for yeah so we can't store all that data so that's why we have this the computers there to crunch it so it gets there's a bank of GPUs in one of those shipping containers and that crunches the data so that we are effectively so for Mata for the project that I'm working on the fast radio bursts project we get data every millisecond in 16,000 frequency channels so that's about 142 gigabits per second so online so that 13 terabytes per second in real time gets crunched to 142 for a second for us the cosmology data rate is is lower than that actually so a lot of the computing has to be done at the site and it takes a lot of power at the site your chyme telescope you got 400 to 800 megahertz s lower than what you've been seeing before why is that just a result of yeah I see you're at so the F R B's I mentioned before were are all at one point four gigahertz and we're at 400 to 800 yeah that's a great question so that as I said the telescope was designed to do cosmology of red shifted hydrogen and so the hydrogen emits a line at 1400 megahertz but if you want to study red shifted hydrogen that that is hydrogen is moving away from you due to the expansion of the universe then the that line appears at a lower radio frequency and so 400 to 800 megahertz the cosmologists chose that range because that corresponds to a distance in the universe where the where the expansion of the universe is accelerating and it's a particularly interesting choice for doing cosmology and studying dark energy for us I mean they were building the telescope anyway and so there is a little bit of concern that the fast radio bursts phenomenon how do we know that you'll detect it will detect it between 400 and 800 megahertz when it's been seen mainly at 1,400 megahertz and there are several now fast radio bursts who have that have been seen between 700 and 800 megahertz using different telescopes that I didn't have time to mention so we know that at least in the top part of the chyme band they exist but at frequencies lower than 700 megahertz we don't actually know if they're there and so on the one hand it's a bit of a risk but it's but what the telescope is going to be built in anyway we had no say we took what we got and I also think because we know that they exist between 700-800 it's also quite an interesting range to see what happens below that so our best estimates when I say between a few and a few dozen per day are trying to account as best we can for what we think the frequency behavior of them is but we don't know for sure is there any plan to have two sites make the measurement you mean to do Metheny ously yeah yeah so we would love to do that and and so you you're saying that because you realize that if you could do it simultaneously then you could get a position very precisely I assume that's why you're asking that so to do interferometry using the two telescopes you could get a very precise position so one thing chime cannot get us alone is a position good enough to go and see if there's a galaxy there so we might detect a thousand fast radio bursts but there won't know what galaxies are there unless some of them repeat and then we go to an interim eater but if we could do it in real time and have multiple chimes if we could do that and we're talking about it I mean there's no reason you couldn't do this it's just money but if you could it would be great because it you'd have the positions for all of them just like that and even the ones that don't repeat so if there's really two different classes you'd love to be able to do that you mentioned that other radio telescopes focus to a point whereas chime is more of a line is that going to inhibit your ability to determine where it is in this guy yeah that's a great question so let me show you something I was hoping somebody would ask that question so it happened to have a slide roll prepared for this so if you put a single antenna on one cylinder and so this is a representation of the sky and the the horizon okay it's the light part of the sky and you can see basically a whole region north/south and you can't tell where the if you'd second it fast radio bursts all you know is that it's somewhere in that strip you don't know where in that strip but then if you put many antennas along that line and you put them into a correlator so basically what you're effectively saying it seeing is the slight time delay between the different antennas if that if the source is over here then it hits this one first and then this one is it so you basically combine the signals of the antennas using a computer and you look it's as if you're looking for the correct delay that lines them all up that pinpoints it on the sky at least in the north-south direction so you can say in which of these beams this the event arose and then if you put antennas on all of the cylinders you can get information on the east-west direction as well so but this requires the student the supercomputing is so so basically what China's doing is the number crunching on site is providing us this stream of data at every millisecond for a thousand different beams on the sky so it's like we have a thousand Parkes telescopes all at the same time and we're searching a thousand Parkes telescopes for fast radio bursts at the same time so this is why it's it's a it's challenging are the aliens giving the signals oh that's a great question and I get you know I get that question so often no I feel very confident that this is not aliens and although it's a very reasonable question to ask but we see these sources all over the sky and from as we believe very different distances there's no the technology you would need to produce a signal like this maybe somebody could invent something like this but they couldn't talk to somebody on the other side of the universe and explain to them how to do it so the fact that you see it all over the sky tells us that this can't be something it has to be something natural it has to be a natural phenomenon there's no way that those parts of the universe know about each other and communicate so no we do not believe these are aliens hey I was wondering yeah why you are focused only on ground-based telescopes and if there was any ideas of using something like Lisa if it ever gets created to really see on the largest scales right so we're very fortunate that radio waves can get through our atmosphere and so for example we don't need to this there's no blurring at these frequencies of the atmosphere so for examples you use the Hubble Space Telescope to be above the atmosphere to get rid of the atmosphere of blurring or x-rays don't get through so you need an x-ray telescope to be in orbit so for something like Lisa which is sensitive to gravitational waves you can also do that on the ground and that's what the event of advanced LIGO the laser interferometer gravitational-wave Observatory does from the ground Lisa will do it extremely well as you're saying from space but in a different frequency band different frequency band of gravitational waves but you're raising a very important point that let's say fast radio bursts let's say there's two classes there's the repeaters and there's non repeaters the non repeaters could be colliding neutron stars colliding neutron stars produce gravitational waves that could be detected by a gravitational wave Observatory and that's the sort of thing that time could discover and the problem is that you don't know when that's going to happen either so having a large field of view makes it easier it gives you a better chance to detect something like that but we don't need to go to space for the radio waves because they get through the atmosphere so thank you for sharing your research is fascinating you've talked about what it's not but do you have any hypotheses about what is causing them yeah [Laughter] well I'll say the repeater so so separate the repeater add the repeater it's it smells a little bit like a neutron star in that we know of neutron stars in our galaxy that produce bursts albeit not in radio waves they produce x-ray and gamma-ray bursts are called magnet ours very highly magnetized neutron stars their magnetic fields are unstable and they can lead to massive explosions and we see that in our galaxy some of them do produce some radio waves but the fast radio bursts are wait like a billion times brighter so on the one and in principle a magnetar could have that kind enough energy to do it but only for so long so we've now detected hundreds of bursts each of which is really energetic and so you can do a calculation a magnetar with what we know about them could do this you know maybe for a hundred years and we've only observed this one for three or four years but it will have to start petering out soon if it's good if that's gonna work now a hundred years a long time and maybe we've just caught it at the beginning but if it's somewhere in the middle of its lifetime is most likely than it should eventually be slowing down but the the ones that doll repeat or at least haven't yet been observed to repeat this I really am pretty agnostic I don't have you know man cars could do it that things falling into black holes could also potentially do it so I don't have a favorite one for those thank you those false signals from Australia during the lunch hour Polly Tron's or whatever they were called parrot oh yeah do those display the dispersion characteristics yes and and it's a very you could you could easily you could ask why would a microwave oven do that but doesn't that kind of blow up I mean don't you have any other way of determining that they're so far away other than that dispersion characteristic so so since the first question of what the microwave oven does it for some reason and why they do it we don't know and you're saying doesn't that call into question any dispersion except that in our galaxy we observe thousands of these radio pulsars that have mentioned that produce regular pulsations of radio waves and we we know them all over the sky and they're all have this dispersion characteristics so in our own galaxy we we know this effect exists we've could we can confirm the distances that they imply and so it's it's very well-established the effect of cold cloud plasma and dispersion is is known it's an electromagnetic textbooks it's it's not a surprise to us at all the only surprising things are fast radio bursts is the degree of the dispersion is so much larger than what can be from the galaxy-eyes I would love to answer all the questions this okay hi interesting talk is there any way or do you know what the mass of that small galaxy is and how it might compare to the mass of other larger galaxies yeah it's it's a very small like a percent of the gas I of the Milky Way galaxy for example so it's no supermassive black holes oh well that's actually a really interesting question because we do believe that there's massive black holes at the Centers of every galaxy and so so as I now venture into the field of galaxies which is new for me I mean I I've lived my whole life inside this galaxy so I know a lot about our galaxy but now I so it turns out we don't really and I think there's there's people I know from astronomy group here that studied these tiny little little galaxies and it's unclear if they have supermassive black holes in them so this is an open question fruit for dwarf galaxies do all have massive black holes or or do any have massive black holes it's actually not clear and for those of you have been to the southern hemisphere you might be familiar with the Magellanic Clouds which are neighboring dwarf galaxies to the Milky Way galaxy lovely easy easy to see in the night sky in the southern hemisphere we don't know if they have massive black holes I call like a mine at McGill is trying to actually answer that question Darrell doubt professor Darrell Haggart is working exactly on that question so yeah we don't know it's an interesting question I had a quick question to the fr bees particularly the repeating ones where they predicted by any theoretical work absolutely not do they take to the discredit any fear and of course well they don't just didn't know they they don't discredit basically it was a phenomenon that was found by accident the my colleagues in Australia we're searching for radio pulsars in our own galaxy and just happened to set the upper limit on the dispersion measure to which they searched to something ridiculously high not thinking they find anything but computationally it's actually easy to search it's a very high dispersion and then they found one and they and so did the repeater ruled out at least for that source a whole bunch of classes and models but it didn't really he didn't really discredit anything no okay is there any periodicity or other patterns in the distribution over time for this person yes so if it's a neutron star you would expect that the repeaters burst would come periodically because repetitions in the neutron star correspond to the rotation and we've been looking for that and no and even sometimes we've detected you know ten in half-an-hour and the first thing we do is look for a periodicity they don't seem periodic and that so that's another that's one reason you know could it be a neutron star well if we found repetition a periodic repetition huh that would be so neutron star that would be it but it's not does that rule out a neutron star not really the questions are fantastic so I hate to cut them up well let's do two more questions one for each microphone and then we'll thank our speaker again thank you so chime will give us if it if it's successful it will give us a lot more examples and what's your strategy in terms of how that will potentially lead to understanding the source of these it lead to what sorry how what's your strategy for using that to help get to the source right so with time we're hoping to detect you know a thousand odd you know per year or at least and so first of all you can ask questions like are they isotropic on the sky so if they're cosmological population they better be isotropic and so far the 30-odd are roughly isotropic there's some hint that they avoid the plane of the galaxy but that could be just because there's a lot of plasma in the plane of the plane of the galaxy and that can have effects on their detection so you could ask that or you could ask what is their distribution of of intensities how bright are they and or you could ask once you have a large statistical sample you could say do the ones with the highest dispersion measures are they the faintest ones because maybe they're the furthest ones away so you could start to answer population questions like that but because chime searches for fast radio bursts 24/7 in the sky keeps coming back we can also identify repeaters very easily so we're also hoping that we'll pick out all the repeaters and then we can localize those using an interferometer we'll have to totally take over the VLA to do this it's a problem we need we need a dedicated VLA to do this which is why I think we might we need multiple times but then you can localize them and do they all come from dwarf galaxies or maybe we'll find only repeaters or into RF cavities so once you have a large population to work with there's many ways to get out the problem none guaranteed to work to answer it but at least we'll know a lot more regarding the repeating fast radio bursts like the one where you get ten within a half an hour session is it possible that something like grab extreme gravitational lensing in the same form is like Einstein's cross has kind of multiplied the signals or has that been a little bit so actually the that's a really really interesting question so we don't think that it is necessarily gravitational lensing currently the best hypothesis for those or one hypothesis is that there's something called plasma lensing going on so if you look at the different bursts even and I I did actually I think I showed it might not have been so obvious but if you look at the series of ten births we discovered that day at Arecibo each one's a little different and they have different frequencies structures somewhere brighter at the top part of the bands and where dimmer is the top part of an they looked a little different and there are some models being developed by colleagues of mine Jim Cortes at Cornell University for example that try to explain the different behaviors and some of the repetition by being lenses of plasma around the source and it's a very interesting interesting hypothesis but yet yet to be proven okay all right several thank-yous to make first of all thank you to all of you for coming out tonight and sharing this race really appreciate your support there are various people who have made this all possible Katherine the Kate hackathorn Sharon we are a number of other people I'm not mentioning that but they all came together and contributor and it's but again you're the most important part of this and I think it'd be a perfect time to thank thank you for absolutely fantastic [Applause]
