Astrophiz 183: Dr Rebecca Davies – Galactic Outflows

LISTEN: https://soundcloud.com/astrophiz/a183-dr-rebecca-davies-galactic-outflows

Intro music: Gravitational Wave audio of black holes colliding, then ‘Radio Waves’

Full Transcript:

Welcome to the Astrophiz podcasts …
My name is Brendan O’Brien and today is Wednesday the 15th of November. We’d like to acknowledge Australia’s first astronomers, the Aboriginal and Torres Strait Islander people, the traditional owners and custodians of the land we are on.
This episode is produced on Yorta Yorta and Wurundjeri country.

And we’re asking you to influence your local politicians with the message that we really need to change our energy policies and move to renewable energy sources to mitigate the effects of climate change.

And each month we love bringing you two fabulous episodes; On the first of each month, our friend, molecular pharmacologist, toxicologist and amateur astronomer, Doctor Ian ‘Astroblog’ Musgrave brings you his monthly SkyGuide with all the essential observational highlights for telescopers, astrophotographers and naked eye observers.
Each month, Ian also includes “Ian’s Tangent” where he takes us on a short journey of astronomical wonder.

In the middle of each month. We bring you an exclusive and in depth interview with a noted astrophysicist, astronomer, particle physicist, radio telescope engineer, data scientist or space scientist.

And right now, we’re going to zoom down to Melbourne Australia to the ARC Centre of Excellence for All Sky Astrophysics in Three Dimensions at the Swinburne University of Technology to speak with an amazing astrophysicist, Dr Rebecca Davies.

Brendan: Hello, Rebecca.

Rebecca: Hi Brendan.

Brendan: Today listeners, you’re invited to a very special conversation, and it’s my pleasure to introduce you to Doctor Rebecca Davies who’s back in Australia now, three years after being awarded her doctorate from the Max Planck Institute for Extraterrestrial Physics in Germany. And Rebecca is now an Astro3D postdoctoral researcher at the Swinburne University of Technology in Melbourne, Australia.

She’s won many scholarships, awards and fellowships and she’s just been awarded a coveted a ARC-DECRA fellowship. But we’ll hear a bit about that a little later … Rebecca researches the stuff that flows out of Galaxies AKA ‘Galactic Outflows’ … and she looks across the majority of the history of the universe from right now and right back through time to less than a billion years after the Big Bang.

And she uses spectroscopic data from Hubble, JWST … the Awesome James Webb Space Telescope and the VLT, the Very Large Telescope which consists of a optical array of four 8.2 m telescopes high up in the Atacama desert in Chile.

From these data. Rebecca is creating new understandings of how Galaxies evolve, filling in some of those gaps in our knowledge. And she’s just finished organizing and conducting an international Outflows Conference and her students are in multiple research groups on related quests to understand galactic evolution.

Now, when not doing Astrophysics. Rebecca can most likely be found bike riding or playing violin … and she’s currently a violinist with the brilliant Zelman Memorial Symphony Orchestra in Melbourne.

Oh, and congratulations on your latest award … that ARC-DECRA Fellowship which launches soon.
So, thank you for having a chat with us today Rebecca.

Rebecca: Thanks very much Brendan. Thanks for inviting me to this podcast. I’m really honoured to be here and have the chance to share my love of astronomy and research with your audience.

Brendan: Well, there’s so much research material you’ve got, that I found it really difficult to cut it down to keep us under the hour, Rebecca and that’s great.

So look … before we talk about your Quasar, your Carbon4 and galactic outflow research project and your very recent outflows conference and your supervision work, can you tell us where you grew up, please, Rebecca? And could you tell us how you first became interested in science and space and all that stuff out there?

Rebecca: Yeah, of course. So I’m originally from Sydney. I grew up in a family that was quite curious about science. My dad is trained as a mechanical engineer and as kids around the dinner table, we had lots of interesting discussions about new discoveries in science and technology, like quantum physics and computers and the like. So I was definitely interested in how things worked from quite a young age.

I remember that in junior high school, I realized that I really liked to think in numbers and patterns. I enjoyed maths and physics much more than chemistry and biology because I could really learn formulas and patterns and then apply my understanding to solve problems rather than having to just memorize lots and lots of facts which I really didn’t like very much.

Then in senior high school, my grandparents gifted me a subscription to Cosmos Magazine. And I remember reading through the articles and being really particularly captivated by the articles about cosmology and the Square Kilometer Array, which funnily enough was already being planned at that time.

So I think by the time I started university, I definitely already had an inkling that astronomy might be the way I want to go.

Brendan: Fantastic, cool. So please could you tell us a little bit about those school days and your earliest ambitions and how did those early ambitions change and evolve?

Rebecca: Yeah, I think it’s quite interesting. So I didn’t really know it at the time. But looking back, I think in my high school days, I already knew that I wanted to go into research. I did a couple of fairly substantial independent research projects during high school, which I really enjoyed, even though they were nothing to do with science. Actually, one of them was about the Women’s Suffrage movement. And the other project was about a piece of music called The Rite of Spring by Stravinsky.

Brendan: Nice!

Rebecca: So I was really enjoying research even outside of the realm of science. For me, I think a really pivotal moment in my journey was when I went to the Physics Olympiad Summer School run by Australian Science Innovations. And I spent two weeks at Monash University, basically learning first year university physics. Some of the tutors were students from the Australian National University and they were enrolled in this degree program called Bachelor of Philosophy. It’s basically an advanced science degree where you get to do a significant amount of research.

I was really hooked and that’s how I ended up later going to the ANU to study that degree.

Brendan: Fantastic. Thanks Rebecca. So after that successful school career, you were awarded your first bachelor’s degree with honours and won the University Medal for your work in Astronomy and Astrophysics at the ANU, the Australian National University in Canberra.

And I had a look at your thesis for that degree and it looks like you were already in love with spectroscopy. Could you give our listeners an outline of what spectroscopy is, please, Rebecca?

Rebecca: Yes, definitely. So for sure, I was in love with spectroscopy then and I still very much am

Spectroscopy I think is one of the most powerful tools that we as astronomers have to learn about the universe around us.

The concept is pretty simple really, you take the light collected by a telescope and then pass it through something like a prism which separates the light into different colours or wavelengths.

And that’s what we call a spectrum. By separating the light like this, we can actually determine which chemical elements are present in distant Galaxies. In high school science, you learn that electrons can only occupy specific energy states in atoms and to move between these energy states, an electron either has to absorb a particular wavelength of light to go to a higher energy level, or produce a particular wavelength of light to go to a lower energy level.

And the simple consequence of this is that each element forms a barcode of light and dark patches on a galaxy spectrum.

So by matching these patterns of light and dark patches that we see with models for different atoms, we can actually learn about how different elements were formed and transported throughout the universe.

And to me, that’s just amazing and super super cool.

Brendan: Fantastic! Cool indeed! Thanks Rebecca.

Now that sounds like forensic science on a galactic scale to me.
So could we continue back to your astro journey and do a science dive into your PhD research from Canberra?

You headed over to Garching in Munich to the Max Planck Institute for your PhD where your focus was on when star-forming Galaxies were at the peak of cosmic star formation activity and black hole growth … which was 8 to 11 billion years ago.

So could you tell us two things?
First … How did you move over to one of the most respected astronomical institutions in the world? How did that come about? … and was it serendipity? … Was it excellent planning?

And secondly, what did your PhD research reveal about how Galaxies developed during that peak period of star formation and black hole growth?

Rebecca: Yeah. So I had decided a few years into my undergrad degree that I definitely wanted to do a PhD and also that I wanted to go to Europe. So my undergraduate advisor was Lisa Kewley, who by the way, is now the director of the Harvard Smithsonian Center for Astrophysics.

She recommended that I study overseas to broaden my horizons and expand my research networks. I’d already been to Europe a couple of times for travel and I really liked the culture and the lifestyle there. So that’s where I wanted to go. Lisa supported me to attend conferences as an undergrad student and this was absolutely amazing. I was also able to visit places like Oxford and Cambridge and meet some of the leading researchers in the field. So I think I had quite a few potential options for where I could go.

I sent the Max Planck Institute an email saying that I was interested in applying for a position and they flew me to Munich for a seminar and an interview and then offered me a position and the rest is history.

So I think it was partly planning and partly a good luck and timing. So in terms of the research, as you mentioned, my PhD focused on Galaxies during the peak period of star formation activity and black hole growth in the universe.

Now, that’s a bit of a mouthful. So what does it actually mean?

Well, if we look at all the stars and Galaxies in the universe around us, they haven’t been forming and growing at the same rate all over all of cosmic history in the early universe.

The first stars and Galaxies gradually started appearing as cold gas clouds which collapsed towards gravitational centres. As more and more structure formed, the speed of galaxy and star formation increased, but it didn’t keep increasing forever.

In fact, it actually peaked relatively early, which was around 10 billion years ago. And this is the so-called peak epoch of star formation.

Since then, the rate of new stars forming has been declining. It turns out that most stars in the universe actually formed during the peak growth phase. I like to think of this as something like the universe’s teenage growth. So if we want to understand how Galaxies came to be the way they are today, then we really need to study the factors that were influencing and shaping their growth 10 billion years in the past.

Now, my PhD was particularly about Galactic Outflows. You can think of these kind of like big fountains of gas or cosmic geysers being launched from Galaxies. They’re powered by exploding stars, supernovae or accreting black holes, which release large amounts of energy and push away gas from the Galaxies.

Astronomers think that these outflows are one of the most important processes impacting the life cycle of Galaxies. They remove gas, which would otherwise be used to form stars. And this means that they fundamentally limit how fast Galaxies can grow.

In my work. I used a special type of spectroscopy called integral field spectroscopy, which basically means that um instead of having either an image or a spectrum, you have both, you have a spectrum for every spatial location across the galaxy, giving you a three dimensional data cube. And this means you can map out flowing gas across different parts of the Galaxies.

Using this data, I investigated how the star-forming regions determined the properties of the outflows. And in turn how those outflows influence the future growth of the host Galaxies.

And I think one of the most interesting results I find was that if you look inside an individual galaxy, the parts of the galaxy forming more stars will launch outflows at higher speeds than the parts of the galaxy forming less stars.

And we can compare these observations with predictions from models to learn about the actual physics governing the outflows.

Brendan: Oh, that’s fantastic. That’s beautiful. Thanks, Rebecca.
Well, look, you mentioned the teenage years of the universe. We’re now at 13 to 14 billion years of age. If the star formation was peaking 8 to 11 billion years ago, Does that mean that the universe is already fading to blackness? And what are you and other cosmologists saying about the fate of our universe these days?

Rebecca: Well, first of all, I want to say that I’m definitely not a cosmologist and the fate of the universe is not my top area of expertise. It is true that the rate of new stars forming in the universe is already about 10 times less than it was at the peak.

And this we think is mostly because Galaxies are not getting as much gas from their surroundings. So they have much less fuel to form stars than they did in the past. As far as I understand, the number of stars forming is predicted to keep decreasing slowly as time goes on. And eventually, what will happen is that the existing stars will die faster than new ones form and this will cause the universe to get darker and darker, but it will be a very long time before this happens.

I read somewhere that stars will probably keep forming for another one trillion years into the future. And that’s almost 100 times longer than the current age of the universe. So we’re talking about things happening on very, very long time scales.

Brendan: Fantastic. Something worth waiting up for Rebecca. Heheh Ok. Thank you. My head’s spinning a bit. Could I recover and go back to your astro journey for a minute? You had four years in Munich. It must have been fantastic doing your PhD there.
How did your German language skills develop in that time? And did you get to see some of the rest of the country. Germany really is fabulous. And what were your highlights of your time in Germany? And at the Max Planck?

Rebecca: Yeah, it was a really fantastic experience living in Germany and in particular Munich, I think. I mean, the city is really beautiful. It’s gorgeous. I had a really nice time living there and I’m so glad I had the chance to do that.

I actually studied German language at high school for a few years. So I wasn’t starting from scratch, which helped a lot.

It turns out that doing my PhD in Germany surprisingly didn’t help my language skills to develop very much because the team I was working in was very international and we essentially spoke English all the time.

So the way that I learned the most German was by joining a choir where all the rehearsals were in German and I made friends that were very helpful. I definitely got to do some traveling around Germany as well as other parts of Europe. I particularly loved going to the Alps. They’re only an hour and a half by train from Munich and the scenery is absolutely stunning. Uh You can go for really nice hikes on the sunny days in summer and in winter, the mountains are covered in snow and you can take the cable car up and just enjoy this unbelievable scenery that you wouldn’t get in Australia.

I also visited many other German cities like Berlin, Dresden and Nuremberg. And it’s actually really interesting to see the contrast between the types of architecture and city design in the former West German and East German cities there. There’s really quite a contrast there.

I think my absolute favourite travel highlight was road tripping around Iceland. The landscapes are absolutely breathtaking. So many waterfalls and volcanoes and mountains. I was really frustrated that I didn’t get to see the northern lights because the one night that we had a really strong aurora forecast, it was cloudy. I think I’ll have to go back again sometime to see those northern lights.

Brendan: Ok. Thanks Rebecca. So you nailed your PhD and headed back to Australia and landed right in the middle of the COVID pandemic.
Now, would you like to tell us about … um we have a lot of early career astronomers listening to this podcast, so would you like to tell us about how you went about securing your first post doc position at Swinburne University?
And how did COVID impact on the research and teaching environment that you landed in back then?

Rebecca: Oh, yes. So this was a big adventure. I started applying for jobs before the pandemic hit. So at the end of 2019, and I was actually off at the position at the beginning of 2020.

So this was just before the pandemic started when the pandemic hit and the Australian borders shut. I was very worried about whether I’d be able to move back to Australia in October, as I had planned.

Five days before I was supposed to leave, just after I’d sold all my furniture and packed all my boxes, my flights were cancelled.

Luckily I was staying with friends and I had a place to stay on someone’s couch. I called the airline, and managed to get another flight less than a week later from Frankfurt to Adelaide.

So I took the train from Munich to Frankfurt. And then the next day, I was thankfully allowed on the flight to Adelaide. Once I got to Adelaide, I faced two weeks of hotel quarantine. Luckily I was with my husband so we could keep each other company.

I also started working on my post-doc job over Zoom from the hotel quarantine and this gave me a good way to pass the time.

Although I got to Australia in November 2020. I actually didn’t move to Melbourne until January 2021 because everyone was forced to work from home anyway. And of course, Melbourne endured many more months of lockdown in 2021. So I spent a lot of time working from home in that first year. I am very grateful that it’s all in the past now and we can see each other face to face because I much prefer being in the office with my colleagues and being able to have casual conversations.

Brendan: Indeed. Ok. Thank you. Uh Look just one more thing before we put our science hats back on. Could you outline your current research role and your supervision responsibilities at Astro3D at Swinburne University? And what is Astro3D?

Rebecca: Yeah. So currently my position is as an Astro 3D funded post-doc. Astro 3D is the Australian Research Council Center of Excellence for All Sky Astrophysics in Three Dimensions. That’s a big mouthful, but basically, it’s a collaboration of more than 200 researchers across nine universities in Australia and some overseas.

I was hired to analyse high quality spectra of very distant quasars from a survey on the Very Large Telescope called XQR-30. And my job was to use these light barcodes that I mentioned to catalog chemical elements in distant Galaxies.

Once I had this catalog, I used it to study the cosmic history of Carbon_IV aka ‘Carbon 4’ which I think we’ll talk about in a couple of minutes.

And I’m currently supervising an Honours student and a PhD student who are both using my data catalog to investigate the properties of the very early universe.

Brendan: OK. Thanks Rebecca. So let’s get into some science again. You spoke earlier about conditions in the universe when it was a teenager 8 to 11 billion years ago. And what we know about the early universe. And your most recent research has looked even further back in time to when the universe was a ‘baby’ and only a billion years old after the Big Bang. Can you just explain to us how we know what we know?

Rebecca: Yeah. So if we’re thinking about, for example, the rate of stars forming over the history of the universe, we’ve studied this by using powerful telescopes to collect light from distant Galaxies. In particular space telescopes have been really helpful for this like Hubble and Spitzer.

Now, the James Webb telescope is completely transforming our understanding of the distant universe by providing us with accurate data on these far away Galaxies. Now light released from these distant Galaxies becomes redder as it travels towards us, because some of the energy of the light is converted into the expansion of the universe. This is what we call red shift. So light from young stars in very distant Galaxies becomes redder as it moves towards us. And by the time it reaches us, it’s at infrared wavelengths that can be observed by the James Webb telescope. And this is why James Webb is discovering so many new far away Galaxies that we could never see before.

Brendan: OK. That’s fantastic. Yeah, James Webb is just awesome. Now, I had a look at some of your journal papers and a lot of your work involves quasars and carbon four. So could you give our listeners the basics of what quasars are and what carbon four is and how you use them to build your understanding of that very early universe and how those early Galaxies evolved?

Rebecca: For sure. So quasars are supermassive black holes that are eating up gas so fast that the disc of gas and dust surrounding the black holes heats up to very high temperatures and this produces extremely bright light that we can use a bit like a cosmic flashlight.

Quasars are very useful because they give us a way to see Galaxies that are too faint to detect on their own. You can think about a fly being lit up by a car headlight. You would never be able to see the fly if it wasn’t being illuminated by this bright source behind it.

So as the quasar light passes through Galaxies, chemical elements in those Galaxies absorb light at specific wavelengths producing these barcode signatures that I talked about earlier. When looking at the quasar spectra, we commonly see the chemical barcode for carbon four, carbon four is just triply ionized carbon, meaning that it is carbon that has had three electrons stripped of it.

And this can only form in hot low-density gas surrounding Galaxies. So using the catalog that I made, I was able to determine how the amount of carbon four in the universe changes over time.

And what I found was that there is a very steep drop in the amount of carbon four between about 12.5 billion years ago and 13 billion years ago. That’s really not a very large amount of time on astronomical timescales. So it’s quite surprising that the drop is as steep as we see.

Now, there could be two causes for this, either the total amount of carbon is dropping or the number of electrons stripped from the carbon atoms is changing, and we call this the ionization state.

I tested both scenarios and found that neither of them seems to fully explain what we are seeing. The decrease seems to have been partly due to a decrease in the amount of carbon. And that’s just because stars progressively produced elements over time and partly due to carbon having less stripped electrons earlier in the universe.

The second part is particularly interesting because this might be linked to what we call the re-ionization of the universe, where the first stars and Galaxies ionize the neutral hydrogen gas in the space between Galaxies.

And my research suggests that this light may also have caused more electrons to be stripped from carbon atoms over this short period of time.

Brendan: Wow! That’s amazing! And that’s the best explanation of what quasars are that I’ve ever heard Rebecca … Thank you so much!

And … Yeah … You … You’re a detective as a physicist that’s astonishing science.

Let’s keep going. And we always ask you a couple of technical questions for listeners who like to put their propeller hats on when they listen to an episode.

So could you talk us through some details of a particular paper or other part of your research that you’re working on right now that’s driving you crazy or is astonishingly exciting or perhaps even both?

Rebecca: Yeah. So I’ve just finished a very exciting paper using data from the James Webb telescope which will be on the ArXiv-dot-org website very soon … it probably should be out by the time this episode is published.

The main result of this paper is that powerful cool gas outflows were very common in high-mass Galaxies 10 billion years ago.

We discovered the outflows by studying sodium absorption lines in galaxy spectra. These lines were not detectable without the James Webb telescope because the galaxy continuum light is just too faint to see from the ground. And we know that the gas is outflow because the sodium lines are actually slightly shifted in wavelength compared to the hydrogen absorption lines from the stars.

The Doppler effect means that the light from gas moving towards us is shifted to slightly higher frequencies. And this is similar to the pitch shift you hear as an ambulance approaches you.

So these findings are exciting for two reasons.

First of all, it gives us a great new way to study cool gas in distant Galaxies, meaning relatively low-temperature gas. And this type of gas is very important because it can eventually become the fuel to make new stars.

Secondly, our data suggest that these outflows might actually be preventing star formation, causing the Galaxies to die.

We see some Galaxies with very little star formation but outflows expelling gas at an unbelievable rate. And this suggests that basically the outflows are stealing the gas from the galaxy, so it can’t make any new stars.

I’ve just submitted a proposal for follow-up observations with James Webb, which would allow us to make more detailed measurements of these.

So fingers crossed.

Brendan: Yeah, fingers crossed indeed. I hope you get that time Rebecca. Now we mentioned earlier the Outflows Conference that you had. I mentioned that in the introduction … could you tell us how the conference actually went? Were there some new understandings developed that came out of your conference?

Rebecca: So I thought the conference was really fantastic. I’m probably biased because I organized it and I had a big influence on the topics that were being discussed. So obviously, all the talks were super interesting to me, but it was my favourite conference of the entire year.

We had about 80 researchers from all over the world. It was amazing to have so many Outflow experts gathered in one place. I definitely learned a lot and it gave me lots of new ideas for my own research.

I think one of the best things about having a focused meeting like this is that you get a strong sense for the current frontiers of research in the field and where we should be focusing our efforts next. So I think that was probably the biggest thing that came out of the conference.

And the conference was held in Healesville in the Yarra Valley just outside Melbourne. And all the international visitors really loved the fact that they could head out of the conference room and see kangaroos straight away. So I think that definitely contributed to the success of the conference.

Brendan: Fantastic. Yeah, the Healesville sanctuary there is just beautiful and everywhere around there … kangaroos everywhere!

OK … So you mentioned your students earlier. Now we know the importance of mentoring and teaching and PhD supervising. Are you recruiting prospective PhDs to work on your projects? And you mentioned you’re applying for more time on the JWST, what other new projects are in the pipeline for you?

Rebecca: Thanks for asking. Yes, I am recruiting Honours and PhD students to work on projects in my group, mostly related to Galactic Outflows.

We have data from lots of great telescopes including of course the James Webb telescope as well as Keck, which is on the Mona Kea Mountain in Hawaii and the Alma Sub-millimetre Observatory in Chile.

And as part of my DECRA Fellowship, I have funding for a PhD scholarship. So if there are any enthusiastic students listening or if people know any students that are looking for projects in this area, then please email me for more information.

My DECRA Fellowship is all about studying Galactic Outflows in the early universe. Um So I have been very busy writing proposals, as you mentioned to get new data with Keck and James Webb. And this would be basically to build on my current research and try and understand the relationship between outflow gas at different temperatures. So I mentioned before that uh we’ve just discovered these cool gas outflows with James Webb. Um But most of our previous understanding of outflows is based on ionized gas, which is higher temperature and lower density.

So we don’t really understand how to connect this hotter ionized gas outflows with the cooler gas outflows. And one of my main goals over the coming years is to try and get a sample of Galaxies where we have measurements of both these types of gas to really understand how they relate to one another.

Brendan: Fantastic! The moment we find something new, we also find a whole heap of new questions to follow up on. Thank you very much.

Now, finally, the microphone is all yours and you’ve got the opportunity to give us your favourite rant or rave about one of the challenges that we face in science, in equity and representations of diversity or science denial (which is one of my favourites) or science career paths or your own passion for research, or that huge human quest for new knowledge. The microphone’s all yours Rebecca.

Rebecca: Thanks. So I think personally I’ve spent a lot of time recently thinking about how I can make the most positive contributions to society and the world around me.

And I think as scientists, it’s very important for us to inspire other people to be curious about the world we live in. Curiosity leads to a hunger for truth. And this is a very important step towards tackling any of the issues that we have in our current world, like transforming our energy systems.

Another important thing I think is for scientists to share our research with the public. Many people have this view of scientists kind of as an elite group of people that isolate themselves from the world and reality. And perhaps think that they are better than other people. And we can really tackle this by engaging more with the wider community in a way that’s humble and honest about what science can do as well as its limitations.

And finally related to this, I think it’s really important to educate people about the scientific method and help them realize that science is not rigid and it’s not black and white. There is never unanimous agreement about any theory regardless of what it’s about. But through rigorous testing and refinement, we can continually improve our understanding and put forward our best theories of the universe.

So that’s my suggestions on how we can engage with the people around us.

Brendan: Fantastic! And I see you’re doing that right now. OK. Is there anything else we should watch out for in the near future?
What are you keeping your weather eye on?

Rebecca: So I think I’m constantly keeping my eye on the results from the James Webb telescope. It’s still a very new telescope and we are still working out exactly how to get the most out of the data. And now Cycle Two is underway and that will bring a whole new slew of exciting results and new science and I’m really keen to see in particular what unexpected findings will be coming out of this because we already saw a lot of new results in Cycle One that are really challenging our understanding of the universe around us. So, yeah, I’ll definitely be keeping my eye out to see what new things come our way in Cycle Two.

Brendan: Fantastic! Thank you. We’ll join you on that. Well, thank you so much, Doctor Rebecca Davies from Astro3D … on behalf of all our listeners and especially from me, it’s been really fabulous to be speaking with you. Thank you for explaining how science works, how scientists work, especially that. I really love your explanation of quasars there and how outflows can steal gas from whole Galaxies.

And thanks especially for giving us your valuable time from your amazing schedule and good luck with all your next extra-galactic adventures. Thanks, Rebecca.

Rebecca: Thanks so much for having me. It’s been really great to chat with you.

Brendan: See you next time. Bye now.

Rebecca: Bye

Brendan: … and remember Astrophiz is free and unsponsored, but we always recommend that you check out Doctor Ian Musgrave’s Astroblogger website to find out what’s up in the night sky.

Ok, a couple of notes about our episodes over the upcoming holiday season

… now because Ian has already included his December SkyGuide in his November SkyGuide, our next episode will be posted on a December 1 … and to cap off our 2023 season and another year of fabulous in-depth interviews with stellar scientists, we’re zooming over to the Harvard Smithsonian Center for Astrophysics to speak with PhD candidate Hyerin Cho.

Hyerin has been using her formidable computational skills to simulate still mysterious black holes using supercomputers as well as revealing the mysteries of enigmatic fast radio bursts … AKA FRBs … she produces simulations of plasma accreting onto black holes and is on an already successful quest to discover what really makes his wonderful phenomena tick.

After that, we will be taking our usual summer holidays and taking a few weeks astro-break from Astrophiz.

But rest assured Ian will be back in February to give us our February SkyGuide.

And we’ve got some amazing interviews lined up for you for 2024. I’m looking forward to starting 2024 by attending the TDU in January. the Transients Down Under conference is in Melbourne and I’ll be interviewing some researchers from all over the world who are attending.

Transients are phenomena that rapidly change their brightness. And researchers strive to understand the mechanisms that cause Supernovae, FRBs, fast radio bursts, GRBs … gamma ray bursts, AGNs Active Galactic Nuclei, TDEs – Tidal Disruptive Events, Kilonovas which explode when black holes and/or neutron stars collide, there’s many transients and yes, I’ll be ready to drink some Acronym Soup at TDU.

But the great thing about Astrophiz interviews is that we always get our interview guests to break down their research into something that even I can understand.

I can’t wait, see you in two weeks. Keep looking up!”

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