- Physics world.
- Hello and welcome to the Physics World Weekly Podcast.
I'm Hammi Johnston.
In this episode, we meet an ion source expert at the UK's
National Physical Laboratory, who talks about her passion
for building scientific instrumentation.
And we also chat with an astrophysicist whose work on dwarf
galaxies has helped us hone in on the
properties of dark matter.
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Lilly Ellis Gibbons is a higher scientist at the UK's
National Physical Laboratory in Teddington,
which is on the western edge of London.
She did an undergraduate physics degree in Australia
before working for several years
as a science communicator in schools.
She then did a PhD in atomic
and molecular physics at Spain's Institute
of Fundamental Physics in Madrid
after a stint at University College London.
Lily joined NPL in 2021,
where she works on a wide range
of instrumentation technologies.
Hi, Lily. Welcome to the podcast.
- Hi. Thanks for having me.
- So Lily, you've developed instrumentation in a,
a wide range of applications.
How did you first become interested in working in the field?
- I mean, it was kind of serendipity
because in the final year of my undergraduate, I had to do a
internal project with a professor at the university.
And I was just looking around
and I chose one that worked in fundamental atomic
and molecular collisions.
And this is sort of homemade equipment,
all vacuum equipment,
and the instrumentation is quite intense,
and I enjoyed that.
But when I finished my honors year, I was looking
for a PhD in Australia
and I actually went on a road trip
with another graduate friend of mine,
and we visited the universities
and chatted to different people,
and I couldn't find something that really fit.
And so I did that work
as a science communication officer, which was really great.
But at some point I was thinking, okay, I'd really like
to get back to something more scientific
and a little more challenging.
And, uh, my professor who had I had done that project with,
happened to know someone who was offering a PhD in
Spain in similar work.
So I was very lucky
to be in the right place at the right time
and looking for something, uh, challenging and scientific,
and that I had already done this one project, uh, working
with vacuum instrumentation.
And I just really enjoy knowing how things work.
And I really love instruments that can take
what is an incredibly complicated world
and break it down into smaller
and smaller pieces until you can say something extremely
fundamental about what's going on.
- And your PhD in, in Spain involved the development
of new ion sources for radiotherapy.
Can you talk a bit about this research?
What was the goal there?
- Yeah, absolutely. Um, it was part
of a Marie Curie International Training Network under the
FP seven funding group.
And the project was called argent,
which was advanced radiotherapy generated
by exploiting nano technologies.
And this was quite a large project that involved, uh,
13 different students across a number
of institutes across Europe.
And the institute I was at in Spain was sort
of the fundamental physics branch of this.
What the project was looking at was how, uh, radiotherapy
and nanoparticles can intersect in treatment.
It was focused on ion therapy as a radiotherapy technique.
Ion therapy is where you use ions like protons
or, uh, something a little heavier like carbon plus ions
in the body to help to destroy tumors.
And this works, uh, very well in some cases, particularly
for things like brain cancer and spine cancer
because when you use ions for this type of radiotherapy,
instead of depositing the
energy all the way along the pathway through the body,
so you'll have sort of roughly the same energy deposited,
you know, as it enters the front of the chest compared
to when it enters into the tumor itself deeper in the body.
When you use ions for radiotherapy,
you have something called the brag peak
where the energy is mostly deposited, uh,
at a certain depth into its path.
And so this means that you can have really high intensity
energy deposited straight into the tumor.
And this is really, really excellent for deep-seated tumors.
And the project I was working on was looking at
how when you have this ion therapy,
you are not just shooting these high
energy ions into the body.
You're actually creating with that as a cascade
of lower energy particles.
You have electrons, you have other ions you're creating
and you have radicals.
And these all affect the cells that you're targeting
and they can affect them in lots and lots of different ways.
We were trying to develop iron sources that could
basically show us a very basic system
of those secondary created particles from the initial iron
beam with molecules that you might find in the body.
And we focused on things like DNA bases.
Uh, we were effectively trying to make beams of radicals
and of different types of ions,
and also we had electron beams in the lap as well.
- W when you're making those beams,
or are you trying to understand what's happening
inside the body by making
relatively energetic beams, um, that would, I suppose,
be created during radiotherapy or,
or is the idea to use those beams in a in a
radiotherapy setting,
- Uh, is certainly more to understand what's happening?
So it, uh, produces the kind of data that you can use
for modeling radiotherapy really well.
Um, so to improve models from being, for example,
considering the body to be just water.
If you want it to be a more complex
and more complete model, you also want
to include things like DNA, um, and proteins
and to include those higher mass molecules
and more realistic molecules in your models.
You need a lot of data to understand how they interact
with the components
of the radiotherapy trail through the body.
Um, and it's also quite valid in terms of looking at
how different cells go through cell death.
Um, there was a lot of research done
in the early two thousands around, um, electrons
and how they interact with DNA.
And it was actually found that electrons with very,
very low energy, you know, like, um,
a hundred thousand times less energy than the proton beam
itself can actually disrupt DNA enough to cause it to break.
And this kind of process can, uh,
obviously kill the cancer cells
that you're interested in killing if you,
if you damage the DNA enough, those cells can't survive.
Um, so we were interested in producing data
to make these models of radiotherapy systems,
but also in understanding the chemistry
of what's going on within the cells
and how that might be better utilized in
radiotherapy treatment.
- I see. And and it sounds like that, I mean,
that must be a real challenge
because you're, you must be dealing
with some fairly complicated molecules and
and chemistry in your, in your ion source, how it, I mean,
it sounds to me that it must be very difficult
to actually get the ions out that you want.
- Yeah, I mean, in this case we were trying to work
with quite simple systems.
I think I did quite a lot of work with oxygen, um,
and plasmas trying to make a beam, uh,
of oxygen radicals or negatively charged oxygen ions
because, uh, as there's quite a lot of water in every cell,
you're going to be, uh, having a lot
of oxygen based radicals and ions.
And this can then interact with something as small as
a molecule, uh, with say six or seven atoms.
So you can build the system to be relatively
simple, but it's still quite difficult to get what you want.
Um, plasmas are very complicated things,
and depending on how you are making your plasma
and how you're extracting the different parts
of the products of that plasma, it can really, uh, change
how you can produce enough of the ion
of interest, for example.
- I see. Lily, when I was looking at your, at your cv, I,
I also noticed that you'd worked in experimental
astro chemistry and I was sort of scratching my head how,
you know, how how did she get from radiotherapy to,
to astro chemistry, but I think I understand it now.
Is it were, were you looking at the sort of chemicals
that could evolve in space in Mm-Hmm, in,
in sort of ion, you know, as ions in, in a vacuum chamber?
- Yeah, yeah, for sure.
Astro chemistry is a super fun field. I really loved it.
Um, it is definitely looking at what kind
of chemistry can happen in different parts of space,
and it sounds very different to looking at
how radiotherapy interacts with the body.
But in terms of the techniques we used, it's quite similar.
So you're using ion beams and electron beams in vacuum,
and you're looking at the interactions of these beams
with a molecule of interest.
So in some cases, we would find something
in the literature from spectroscopy.
So people with the telescopes would look at Titan,
for example, and say, oh,
we saw in the ionosphere that there's this molecule.
And we'd say, okay, that's very interesting.
What happens, um, in that environment to that molecule?
Does it break down? Could it form new bonds?
Could it turn into, for example, a singly charged
or a doubly charged ion?
Um, and so yeah, we end up using similar techniques
for a very, very different application.
- I see. And I, I suppose when, when I see astro chemistry,
I, I immediately make the leap to astrobiology and mm-Hmm.
, you know, the, the looking at the chemistry
that could occur on, on distant planets
and lead to the, the emergence of life.
Is that, is that something that, that you look at
as well or looked at as well?
Or is that sort of a bit further down the road from
the research that you were doing?
- That is certainly, um, a point of interest for us.
It's huge in astro chemistry.
Uh, a biogenesis is really fascinating,
and one of the reasons
that we would choose certain molecules to investigate is
because of their potential to do chemistry that would lead
to something like an amino acid.
And for example, I would work with molecules
that had CN bonds
because that's really important in, uh, the kind
of chemistry that happens inside life.
And we also looked at, um, I don't know if you remember,
but there was, I think pH three potentially discovered
in the atmosphere of Venus. Oh,
- That's right. Yeah,
- Yeah.
And everyone was very excited
because that's really only produced in certain kinds
of processes that involve biology, uh, for example,
the rotting of natural matter.
Um, so we also investigated pH three as well, just to see.
Okay. Um, unfortunately,
after further analysis of that telescope data,
they discovered that the likelihood
of pH three being there is actually very, very low.
Um, but we still did some research to see, okay,
if you had it in the ionosphere
or if you had it in the interstellar medium
or in a nebula, um, it's in this environment that has a lot
of electrons or has a lot of ions
or radicals, what happens when you interact this molecule
with this energetic species?
- I mean, it sounds like a very exciting field
because, um, I suppose you've got chemists,
you've got physicists, you've got
astronomers all working together.
Did you, I mean, did you find it very rewarding?
I'm guessing you probably learned lots about planetary
physics and, and things like that while you were doing it?
- Yeah, I definitely learned a lot. It was, uh, very fun.
The conferences are always fascinating
and they have wonderful pictures in all of their talks
because of course, you can just produce these amazing images
from telescope data.
Um, the, uh, overlap
between the people doing astro chemistry
and the people doing sort of, uh, you know, planetary motion
and gravity and things like that is a lot smaller.
Um, but definitely we spoke to a lot of physicists
who are modeling, you know, what the concentrations
of different atoms in different parts
of the universe should be.
Uh, so this, this was always really great.
- And in, in 2021, you joined NPL, and you're,
and you're a higher scientist there.
Can, can you give us an idea of what your job entails and,
and maybe describe some of the projects
that you're working on at the moment?
- Yeah, absolutely. Um, so I joined a group called NICE MSI,
which is, uh, a mass spectrometry imaging group.
And our group mostly works on,
uh, chemical imaging of surfaces.
And a lot of what we do is biological based.
So again, this is, uh, quite a different field in terms of
what we are like looking at practically,
but the instrumentation, again, is relatively similar.
Um, so it's, again, it's high vacuum work
and it's, uh, developing ion sources.
Now, the cool thing that I'm doing now is
that I'm working on ambient ion sources.
So, um, when you have a sample that you want
to look at with mass spectrometry imaging, you often have
to put it in the vacuum or you have to coat it
with something, or you have to, uh, wash it several times.
Um, so for example, if we're looking at, you know, uh,
tissue samples, um, one of the techniques
that we use here is called maldi, which is, uh,
requires the use of a matrix to allow for the transfer
of energy from a laser beam into the material in the sample
to then allow it to be ionized
and detected by your mass spectrometer.
But some samples can't really go in the vacuum
and some samples you don't want to cope with something.
So what I am looking at is how
to look at these samples just in air, just in the lab.
And so I've got a few, um, laser setups, uh,
and we have a plasma post ionization system.
We have a few other types of ambient techniques that have,
for example, a, uh, spray of high voltage
ethanol and water mixtures onto a surface.
And what we're trying to do is, uh,
analyze the different chemicals that are in these surfaces
and produce different maps of these chemicals.
I have a few projects that I'm working on.
I particularly enjoy one
where I'm looking at unusual sample types.
So trying to use these ambient ionization techniques on
things like, uh, plant matter or we had some insects
or we had a collaboration looking at different,
uh, kinds of fabrics.
You know, it's, it's all quite varied and interesting,
but again, it's, it's working on the instrumentation.
And since the National Physical Laboratory is
a measurement institute,
we're also very interested in making sure these techniques
are quantifiable and that they are repeatable
and that we have really high scientific integrity within
the community as well.
- And do, do you do most of your work in Teddington?
Or, or do, do you visit other facilities,
maybe national labs in the UK or,
or, uh, university labs, uh,
that you might have collaborations with?
- Uh, we have quite extensive collaborations across the uk.
We had a project recently
with the Cancer Research UK people, it was called Rosetta.
And we were collaborating, uh, across all sorts of different
institutes like the Rosalyn Frankland Institute
and with different universities as well.
Um, for the most part,
we would do the work within our own labs
and collaborate with them in terms of, uh,
running studies across the different systems.
Um, 'cause obviously each lab can
contribute something different to the project.
And also in terms of analyzing the data in coherent ways.
And I myself haven't done this,
but NPL does have collaborations
with the other measurement institutes across the world.
So, for example, NIST in the us Mm-Hmm.
, uh, we have been,
we have an exchange program of sorts with them.
So there are opportunities, uh, to do that kind
of work across the board,
but mostly we collaborate by, uh,
working on the projects together from our own labs.
- Wow. That, that sounds fascinating.
You know, we might have someone listening who's maybe just
about to finish a, a bachelor's degree in physics,
and they're thinking, wow, you know, a,
a career in instrumentation
that sounds like it could be for me.
What, what sort of advice would you give to, to someone
you know, at that point in their career, if they'd like
to work at a place like NPL or nist?
Um, what, what, what should they be doing?
- I think I would advise, obviously getting time in a lab,
trying to fix things, um, with guidance, obviously,
but actually spending that time
by yourself working on important problem solving
skills is really vital.
I would also say that instrumentation in academia
can be quite risky,
because if you are on a project to develop something
that fails, it's very difficult to then show
that you have the background
to be offered the next fellowship or the next job.
If you are in that situation, then it's always good
to have something, a side project that trundles along
and produces data as well, so that you always have something
to keep publishing and keep pushing.
But there are jobs
and instrumentation that are outside of academia.
So, I mean,
the National Physical Laboratory is an institute,
and we are involved in academia in a big way,
but we're also involved in commercial projects.
And there are also the companies
that produce the instruments that scientists use,
and they have some really amazing scientists
working in development there.
Those can be really excellent pathways as well.
- I think earlier you, you mentioned something about,
you know, working in a lab
where you were building equipment,
I suppose rather than using, you know, sort
of off the shelf stuff.
I mean, is is, is that an important thing
to do early in your career to actually have to sit down and,
and maybe design a, a bespoke piece of equipment
and, I don't know, get the soldering iron out, um, and,
and put it together yourself?
Is that, is that sort of a crucial thing that one should do?
- I think it's very important, um, in terms
of learning those fundamental lab skills, learning
how the electronics work, learning how
to put together vacuum equipment, learning how to model, uh,
for example, in CAD
or Fusion 360, um, you will always, as usually
as lab scientists, you'll be working with
a machine engineering shop, so you'll want
to be producing designs for them to make
and then testing them, and you'll also be having
to put together things yourself.
So I spent quite a lot of time, uh,
and it actually taught me how to stop being so clumsy.
I spent a lot of time putting together very tiny,
very delicate things
with little screwdrivers while wearing gloves.
And so now I'm at the point
where I don't just put my tool down and forget where it is,
and I don't drop everything that I'm holding,
and I can be quite careful when I need to be.
And this is learned through hours and hours
and hours in the lab, putting together
and taking apart the instruments themselves.
- Oh, that's interesting. And,
and is that something that, that you did
before you, you know, be,
before you even started your bachelor's degree in physics,
you know, when you were younger, were,
were you taking things apart and putting them back together
or maybe not putting them back together, , um, or,
or is that something that you developed, you know,
when you studied physics?
- I think, I wouldn't say I was that stereotypical idea of a
scientist or engineer who's like taking apart the toaster.
Um, I have always been fascinated by how things work,
but that didn't necessarily mean I always investigate my
environment, but I wouldn't take something
and pull it to pieces.
Um, that was really something that I developed a passion for
through starting work in the lab.
Hmm. Because I wanted to, I, I want to know how things work,
but I also really like machines that are quite complicated
that can do something that you can't even see, you know,
you can't see an electron beam.
You, you have to imagine it, you have to imagine
how the electric fields are
interacting with those charge particles.
- Is that, is that something that's important in your work?
Is, is having, having the ability
or the experience to imagine what's happening in a system
where you can't see it either an el you know,
an electronic system
where you've got signals going in all directions
or in a, in an experiment, you know, in your vacuum chamber,
you can't just stick your head in there and poke around.
Um, is, is having a a good imagination important?
- Uh, I think it is.
I think being able to, uh,
not necessarily visualize the whole thing,
but to be able to keep a lot
of different factors in your head at the same time is really
important for experimentation.
So if you are, because these things are processes,
and if you don't do everything right in the right order,
you don't get the results you expected,
but you also want to be able to think about
what could be going wrong?
Why am I not seeing signal here?
Where are the points within the instrument where I need
to adjust the, the voltages on this iron funnel?
Or something like that. Like, what points
can I change things in order to get the result that I want?
So I, I think being able to at least understand, visualize
and maintain sort of a catalog of
what you're actually doing is really important.
- Well, that's great. Tha thanks.
Some, some great advice there for, uh, for up
and coming instrumentation physicists.
And, and thanks for talking about your career.
It's, uh, I mean, you've done some fascinating stuff tha
thanks for coming on the podcast, Lily.
- Oh, you're welcome. Thanks so much for inviting me.
It's been fun.
- Perhaps one of the biggest measurement challenges facing
physicists is nailing down the properties of dark matter,
an elusive substance that appears
to influence large structures in the universe.
Here's physics world's Margaret Harris in conversation
with an astrophysicist who is part of a collaboration
that has helped constrain theories of dark matter.
- According to the best developed theories
of modern cosmology, a mysterious substance known
as dark matter makes up 85% of the mass in the universe.
We don know this invisible form of matter is there
because it affects the movement of stars and galaxies,
but we don't know what it is
and we don't have definitive evidence of it interacting
with normal everyday types of matter either.
What we do have, though, are ideas and tantalizing hints.
And here to talk about one of those hints is Alex McDaniel,
who as a postdoc at Clemson University in the US was looking
for evidence of dark matter
and what's known as dwarfs spheroid satellite galaxies.
Hello, Alex, welcome to the podcast.
- Hi. Thank you for having me. - So let's start
with the obvious question.
What is a dwarfs spheroid satellite galaxy?
- Uh, yeah. So dwarf spheal galaxies are, uh, galaxies
that are much smaller than the ones we typically think of,
like the Milky Way or the Andromeda Galaxy.
Those bright big spiral galaxies.
These are thousands of times smaller, uh, much fainter.
Uh, they can have anywhere from tens to tens of thousands
of observable stars.
Uh, so much smaller system.
Uh, and the al part is the shape.
They're just kind of these faint fuzzy little blobs,
small galaxies, uh,
and typically observed nearby, uh, in sort
of the outskirts of the Milky Way.
- How near is near, because obviously astronomer's
definition of what's near is very different
from other scientists.
- Uh, so these are all in our local neighborhood, tens,
twenties of kilo pars Xa on the
order of maybe tens of light years. Okay.
- Okay. And what are you looking
for specifically when you're observing these galaxies?
- Uh, so we're using gamma ray astronomy, uh,
specifically the firmat gamma ray telescope.
Uh, and really what we're looking for is, you know,
we know gamma rays come from various astrophysical sources.
So we model the, uh, astrophysical gamma ray emission
that we'd expect to see from gas
and dust, supernova, pulsars, things like that.
Um, and then what we're looking
for is a little bit more on top of that, trying
to observe something else, another source of gamma rays
that we can't explain with typical astrophysics in these
systems, uh,
that we then would say could be the dark matter.
- So why is it it that gamma rays are a sign of dark matter?
What's, what sort of interaction might be going on there?
- Uh, so in, in the theories that we're testing, uh,
the idea is that the dark matter candidates can undergo a
process called annihilation.
So you have, uh, a dark matter particle
and it interacts with another dark matter particle,
and they destroy each other anytime they come in contact.
Uh, and gamma rays are just one of many different, uh,
standard model particles, you know, particles
that we're familiar with
that we can produce in this interaction.
Uh, so you can get things like electrons, protons,
but gamma rays are really nice
because they're created immediately at the site
of the annihilation event
and they travel directly from the annihilation site
to us electrons.
If they're created, they're gonna travel throughout space,
they're gonna spread out.
Uh, whereas the gamma rays, you get a nice bright signal
and you can trace it directly back to its source.
- Okay. So why is it that,
that these dark matter particles are, are thought to sort
of produce a gamma ray signal in the first place?
- So this is gonna be model theory dependent.
So the, the class
of particles we're looking at are called weekly
interacting massive particles.
Uh, when it comes to dark matter, we know certain things
and it can't have high charge.
It can't be, uh, super relativistic like photons or things.
So that kind of narrows the theory space.
And these, these weekly interacting massive particles
or wis as they're called, are a class of particles
that reproduce The amount of dark matter we know exists also
allow us to have some observable, uh, testable hypothesis.
So, you know, if somebody predicts a theory of dark matter,
but it doesn't produce anything
that no observable predictions, it's not very helpful
for an experimentalist.
Um, so these are very enticing candidate particles, uh,
because they reproduce the known dark matter
and they, uh, support these observational techniques.
- And why focus on this particular type of galaxy?
What is, I mean, isn't there dark matter everywhere?
Aren't these an annihilation events happening, you know,
pretty much anywhere you look?
- Uh, yeah, absolutely.
So what makes the d steroidals particularly intriguing?
Targets? Uh, one, they're, they're very nearby compared
to distant galaxies.
The next plus is galaxy
to us is the Andromeda Galaxy, for instance.
That's about 800 kilo parts X away.
Whereas some of these I've mentioned are on the order
of tens, um, so much closer.
Uh, they're also just loaded with dark matter.
Uh, they don't have a lot of of gas,
so they don't have a lot of
supernova going on, things like that.
That's contamination for us.
So they're mainly dark matter, really dense nearby.
Uh, and this allows for ideally a, a nice clean signal, uh,
compared to looking at, uh, galaxies with a ton
of astrophysical gamma ray emission.
- How do we know that these, uh, um,
dwarf sphe are actually loaded with dark matter?
- Right? So this is, uh, obviously a huge key point
of when we're selecting targets.
It's how much dark matter do these systems actually have.
So some viewers might be familiar
with like galactic rotation curves where
dark matter was discovered, right?
You look at how stars move in the systems
and this allows you to measure
how much mass is in the system.
Um, and we do the same thing with dwarfs.
We measure the, the velocities of stars
as they're distributed about.
Uh, and this tells us how much mass is there in dark matter.
And, you know, comparing that with
how much luminous matter stars mainly, uh, that we see,
we can get a good idea of how much dark matter is there.
And again, these systems are loaded with dark matter over,
you know, 80%
of their mass comes in the form of dark matter.
- Okay? So you're looking for gamma rays,
and these gamma rays might come from a particular type
of dark matter candidate annihilating,
and you're focusing on the dwarf steroid galaxy
'cause they're nearby and they're thought to be good
candidates for these types of decays if they, if they exist.
So you did a study recently
and you found, you found something, what did you find?
- Right. So, you know, typically these studies,
what we're looking for, as I said, is, uh, that little bit
of extra admission compared to to the backgrounds.
Um, and previous studies
that have taken, you know, the same approach.
Typically what you find is, uh, there's nothing else on top.
Uh, and so what we do is you say we can rule out
some parameter space.
We can put some constraints on the models.
Uh, and we do that here. We put some of the most cons,
stringent constraints yet on these models ruling out saying,
okay, it can't be wimps with this type of mass
or this type of annihilation rate.
Uh, but in this paper also, interestingly what we did was,
uh, we saw actually there is a little
bit of signal that we're seeing.
We're seeing a little bit, uh, in excess
of the typical astrophysical models that we've seen.
Now at this stage, it's not at a a, a high enough level
that we, uh, can confirm, you know,
have the, have the big news.
Um, but compared to what's been seen in the past, uh,
we are seeing that that signal is starting
to be extracted from the background, uh,
which is very exciting for us.
- How big a signal are we talking about?
- Uh, so this is in, in the paper.
This is a, a two sigma signal above excess, um, and science.
We'd like to get that to at least a five Sigma
before we can really claim it as a big signal.
Previous studies haven't even typically reported high, uh,
even up to two Sigma before.
So looking forward, you know, to get to that five Sigma,
we probably need at least, you know, 10 more years of,
of data from our telescopes.
- So what, why is it that you need that much more data?
What, what, how do you know
that you need that much more data?
- So one of the things we do in this paper actually is, uh,
we look back at sort of a historical view of these studies
that have been done, um,
and see how much we've improved as data is collected.
Um, and so we can see
how the data collection improves our constraints.
Looking at that, we can also make projections, see
how well those previous projections worked
and make projections into the future
based on data collection.
Right? As we collect more data,
we can still model our background well,
but now we're getting more
and more emission from, from our signal source,
which would be the dark matter.
Uh, we are also looking forward,
we'll be getting larger numbers
of these dwarf zero galaxies.
That's another huge component is we want to be able
to have a large sample size
because we're, uh,
combining observations from all these systems.
In our paper, we did 50 in the near future,
there's some new, uh, optical telescopes
that are coming on big large scale surveys, uh, with some
of the most advanced optical telescopes
and cameras that we've seen that can bring that number
of 50 dwarfs up to maybe 150, 200.
So in addition to collecting extra gamma ray information,
uh, we'll also be in increasing the sample
size of dwarfs that we can look at.
- And supposing this two Sigma sig is,
does turn out to be real.
I know we're getting ahead of ourselves a little bit,
but what would that tell us about dark
matter? If it is real?
- Uh, right. So if this signal is real, you know,
that that'll be a process in the future to,
to really nail that down.
Um, but what it would tell us is that we have a
excellent specific candidate for
what the dark matter could be, right?
We'd be able to say it's a, a wimp a wimp
with specific mass.
Uh, in this paper we were looking at about a 200 GEV range,
which is about 200 times, uh, the mass of a proton.
Uh, so we'd be able to say, if we got this signal
to a Five Sigma or something like that,
here is a very strong candidate
because we've looked at these clean systems
and we have a significant signal.
Um, and what that would lead really is to the rest
of the scientific community following up
and looking at different probes of dark matter to see, okay,
can we confirm this from different angles now?
Uh, can we say this dark matter particle make other
predictions about, uh, what we might be able to see
with other experiments?
And then if it turns out to be dark matter coming from those
other complimentary probes, uh, then obviously that's huge
because this is one of the largest outstanding pro uh,
problems in astrophysics.
- Yeah. 'cause a lot of the, the experiments to try
to find dark matter are,
are whether they're based in earth actually,
and they're, they're sort of big detectors,
maybe buried underground, maybe having lots of, uh,
you know, exotic materials involved.
Um, you know, would anything, are any of those, those sort
of existing detectors, would they be able
to see this signal?
Have you sort of compared back
and forth between the astrophysics side
and the particle physics side? Uh,
- Yeah.
So the, these particle base
or these ground-based, uh, detectors on earth, um,
they also look for this class of particles.
Um, the, the Wims have for a long time been a, uh, kind
of a, a leading well-motivated candidate.
Uh, so they're absolutely looking for it.
And, you know, whether their capabilities would get
to the point to see it directly.
Uh, it is a little hard to say at this stage,
but I think, I think they definitely could, uh, you know,
those are very advanced instruments, very,
uh, powerful tools.
Um, but it, it would certainly help, you know,
with our work, if we can confirm a a,
a five Sigma specific particle, they can kind of hone in
and, and test specifically that model, um, and,
and see if they can see it again.
I think, you know, this, uh, technique that we use, uh,
looking at for the annihilation signal
and in gamma race is putting some of the tight, has put some
of the tightest constraints on models.
Uh, and only now are we starting
to see really something there.
Um, so I, I think they'll need some time
to, to catch up to that.
But certainly with a, a specific model in mind, they could,
uh, start to probe that as well and,
and see if they can see it.
- It narrows down the, it makes the haystack.
They're looking in smaller, I guess.
- Exactly. Exactly. - Yeah.
And you talk about this being a sort
of like 10 year project to find more data.
Are you gonna be involved in that?
What are your plans for the future?
- Uh, so I'm currently now, uh, I've,
I've finished up my postdoc at Clemson.
Now I'm working in, uh, a field outside of academia
and astrophysics and, and finance
and specifically data scientists.
Um, so taking those same data analysis skills that, uh,
helped us put these interesting constraints on this and,
and potentially find a signal, um, and,
and taking that to a new field.
So I've left my, uh,
excellent colleagues on the paper in charge
of updating me in 10 years if this is dark matter
or not. Uh, so we'll see.
- Alex Aniel, thank you very much.
- I'm afraid that's all the time we have
for this week's podcast, which is sponsored
by Racon Vacuum Instruments.
Thanks to Lily Ellis, Gibbons, Alex McDaniel
and Margaret Harris for joining me today.
And a special thanks to Callum Gel, our producer.
We'll be back again next week.
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