chapette.net

Interviews given to the pop-science newsletter The Ph-word in 2018.
Thanks for all the travel tips with a pinch of science + the cool research nuggets!

Juan Carlos Algaba is an astronomer in Seoul National University working on active galactic nuclei - central regions of galaxies which are blasting with energies that cannot be explained only by stars, but involve the presence of a supermassive black hole!

- Juan Carlos, you come from Valencia, in Spain. What would you recommend a tourist who is also a science fan to do or see there?

Valencia is the home of the "Ciudad de las Artes y las Ciencias" (City of Arts and Sciences), an entertainment-based cultural and architectural complex that includes "L'Hemisferic", an eye-shaped planetarium, the "Principe Felipe Science Museum", shaped like a whale's skeleton, "L'Oceanogràfic", an open-air oceanographic park, and the Palau de les Arts Reina Sofía, an opera house and performing arts center, among others. The designs are clean and futuristic and have served as the filming location for the 2015 film Tomorrowland and some episodes of the British science-fiction television programme Doctor Who.

- Will you share a few words about a cool project or discovery that you've worked on?

One of the most surprising feature of these active galactic nuclei is that sometimes they present jets. In short, it's the way the super massive black holes have to deal with all this stuff that they cannot swallow at once. Before it can fall inside the black hole's event horizon and be trapped forever, some material can escape such fate by interacting with the strong magnetic fields and be ejected away in the form of jets. It's like a gigantic aurora reaching distances 10 times the host galaxy. But how these jets are accelerated and shaped is still a mystery. In a recent work, I analyzed a sample of these jets very near the gravitational influence of the black hole and found that they look almost parabolic. This is against 50-years assumption of conical shapes, and may have implications on how the galaxy itself plays a role in shaping these jets, and the way the jets and the stars and gas of the galaxy interact.

Of course we are not happy to investigate only the surroundings of these supermassive black holes. We want to have a look at these black holes themselves! A world-wide project - the Event Horizon Telescope - is connecting telescopes around the world to synthesize a virtual telescope as large as Earth, which will have enough resolution to observe for the first time the largest black holes as seen from Earth: the one in the centre of our own galaxy, the Milky Way, and the one in a nearby active galactic nucleus, M87. Our group in Korea is working in synergy with the Event Horizon Telescope to complement the data and results.

- Many thanks!

Panagiota Papakonstantinou is a nuclear physicist at the Institute for Basic Science in Daejeon, South Korea, exploring the structure and behaviour of atomic nuclei to help prepare for the RAON ion collider.

- Panagiota, what is your suggestion to tourists who are also science fans for things to do in Daejeon?

Personally I never miss an exhibition at the Daejeon Museum of Art, where I have encountered many gems by domestic or international artists of all styles. For our science fans, occasionally there will be an exhibition exploring the section of arts and sciences, often with fascinating results. And of course one can visit for free the National Science Museum and have a go at the interactive exhibits - especially if one has children, it's a popular family pastime.

- Will you share a few words about a cool project or discovery that you've worked on?

One person's cool is the next person's yawn! That said, my specialty is nuclear sound - going at roughly a hundred zetta-Hz, it rings dizzying if not cool. Nuclear vibes already help us understand the stars, but perhaps one day their utility will come closer to earth and perhaps RAON will be instrumental - no pun intended! My coolest endeavor may well be preparing for RAON.

- Many thanks!

Mercedes Miñano Moya is a particle physicist, hailing from la Alberca de Záncara in Castile, in the heart of La Mancha, the land of Don Quixote, and now working for the ATLAS experiment at CERN's Large Hadron Collider, at the outskirts of Geneva.

- Mercedes, what is your suggestion to tourists who are also science fans for things to do in Geneva?

For science fans, a mandatory visit would be CERN (yes, I have not squeezed my head) but where exactly at CERN? There you can find The Globe of Science and Innovation! which hosts the “Universe of Particles”, an exhibition to go deep into the particles and back to the Big Bang. A curiosity: Five special types of timber were used in the Globe's construction: Scotch pine, Douglas pine, spruce, larch and Canadian maple, which enables the building to act as a carbon sink!

Additionally, I would like to mention a lovely night that happens in Geneva in the middle of spring: The Geneva Museum Night! Public and private museums keep open house on an evening in May and for 10 CHF you can enjoy a great variety of activities and visits (with free shuttles between venues and English-speaking activities!). The Museum of the History of Science and Natural History Museum are my favorites! (Don’t miss the bronze statue of famous Australopithecus Lucy to compare your size with the woman known to be the oldest human fossil.)

- Will you share a few words about a cool project or discovery that you worked on?

Sure! Currently I am working in the study of Beam Loss scenario! What would happen if the LHC proton beam deviated and hit directly on our ATLAS innermost detectors? Are our detectors sufficiently hard? We want to know the limit of our instrumentation and if it will allow us to react if such an accident takes place and avoid the malfunction of the detectors.

The ATLAS inner detector is the system reconstructing the tracks left by charged particles. During the LHC Long Shutdown (2024-2026) a new tracker detector will be installed, with an improved all-silicon new design. We want to test the hardness of this new detector and establish its threshold limit.

So we have installed the latest technologies of silicon detectors (pixel and strips) in front of a beam of 440GeV-energy protons at CERN and shoot proton bunches from low to high intensities. The sensor, by design, has a protection structure to deal with very high charge densities. Will it be enough for such instantaneous proton shot?...

- Many thanks!

Jeff Hodgson is an astronomer hailing from Perth, Australia who is currently a researcher at the Korean Astronomy and Space Science Institute. He is researching a mish-mash of black holes, Gamma-rays, and cosmology.

- Jeff, what is your suggestion to tourists who are also science fans for things to do in Perth?

I come from Perth, which has a surprisingly large amount of things to see for the astro tourist! First is the Perth Observatory, which sadly stopped being an operating observatory a few years ago, but it is still open for tours. It actually provided about 10% of the images of Halley's comet when it visited back in the 80s (before I was born)!

We also have the Gravity Discovery Center at Gingin, near Perth, where you can do things like recreating Galileo's experiments!

Of course, nerds will know that the Square Kilometer Array (which will be the world's biggest telescope when finished) is being built in the outback near Perth. The area near there is very beautiful but isn't generally open to the public, but if you're motivated enough, you can go there!

Other cool stuff includes the European Space Agency tracking station (a big radio dish) in New Norcia, near Perth. Further afield, you can see a 1960s-era NASA tracking station in Carnarvon, some 1000km north of Perth. It's worth going there anyway, because it is very beautiful!

- Will you share a few words about a cool project or discovery that you've worked on?

Currently, we are working on a project to extend the Korean VLBI Network to Australia. VLBI (which stands for Very Long Baseline Interferometry), is a clever way of using radio telescopes in different locations by pointing them all in the same direction. This makes an even bigger telescope! So, by having telescopes in Korea and Australia and pointing them in the same direction, we can have a really big telescope, that allows us to detect really small things. We could take a photo of your smartphone on the moon. We are doing this because we want to know how much Dark Energy there was juuust after the big bang... and ultimately to find out if Dark Energy even exists... and if it does... if it's even "energy"!

- Many thanks!

Tugca Sener is an astrophysicist and amateur actress hailing from Ankara, Turkey, now working on neutron stars.

-Tugca, what is your suggestion to tourists who are also science fans for things to do in Ankara?

As a capital city, Ankara is surely suffering a lot from the light pollution but Ankara University Observatory is still active and organizes public events every month. For more of an unplanned activity, I would suggest Feza Gürsey Science Center as it has many experiments and various exhibitions. Also, having a nice breakfast by the Mogan lake might be far from science but I would say you won't regret.

- Will you share a few words about a cool project or discovery that you worked on?

Despite my expertise being mainly on hot subdwarf stars and binaries, the project I am contributing nowadays is on low mass X-ray binaries with a neutron star component. A recent study of a small sample of X-ray binaries (XRBs) suggests a significant softening of spectra of neutron star binaries as compared to black hole binaries in the luminosity range ~10^34–10^37 erg/s. This softening is quantified as an anticorrelation between the spectral index (Γ) and the 0.5-10 keV X-ray luminosity. We propose to extend the study to much lower luminosities (~10^30–10^34 erg/s).

- Many thanks!

Sushant Raut is a theoretical physicist hailing from Bombay and now working in Daejeon, South Korea, where he researches the mysterious neutrino particles (and organizes the monthly event "Science on Tap").

- Sushant, what is your suggestion to tourists who are also science fans for things to do in Bombay?

I was born and raised in Bombay (now Mumbai), India, which has a lot of historical and cultural tourist attractions. For those who love science, I highly recommend the Nehru Planetarium and Nehru Science Centre. The planetarium has many installations on astronomy, and there are daily shows in the planetarium dome. Nehru Science Centre has multiple floors of interactive exhibits on physics, chemistry, biology, mathematics and computer science. It is a place for kids (and curious adults) to get a hands-on experience of the principles of science -- whether it is conservation of momentum, magnetic levitation, human sensory responses, probability distributions, binary numbers, etc. Another fun activity is to visit the Sanjay Gandhi National Park, a vast natural forest within the city limits with a lot of biodiversity in terms of mammals, birds, insects, reptiles and plants. Visiting these places during my childhood definitely played a big role in encouraging me to study science and take it up as a career.

- Will you share a few words about a cool project or discovery that you've worked on?

The India-based Neutrino Observatory (INO) is expected to be built in an underground cavern in southern India. Its main aim is to measure the oscillations of atmospheric neutrinos in order to determine which of the three neutrinos in nature is the lightest. The USP of the INO detector is that it will be made of magnetized iron, which will allow us to observe neutrinos and anti-neutrinos separately.

During my early post-doc days, I performed simulations to understand the capabilities of this experiment to not only measure the neutrino mass ordering, but also other parameters that affect neutrino oscillations. Our results found that INO data in conjunction with beam neutrino experiments could help to measure 'leptonic CP violation', which can explain the abundance of matter over antimatter in the Universe.

- Many thanks!