From ESOblog: “A Nobel Achievement (part I)” Bruno Leibundgut

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From ESOblog


How it feels to be part of a team that makes a Nobel Prize-winning discovery.

Just over seven years ago, the Nobel Prize in Physics was awarded “for the discovery of the accelerating expansion of the Universe”. ESO’s Very Large Telescope Programme Scientist, Bruno Leibundgut, was part of the team that won. In the first post of a two-part series about Bruno’s career, we ask him about his experience at the Nobel Prize celebrations. The second post will be released next Friday and will focus on the science behind the prize.

Q. First of all, could you tell us about the amazing discovery that gained your team a Nobel Prize in Physics?

Twenty years ago, it was known that the Universe is expanding, that other galaxies are moving away from us and from each other. But the big question at the time was: will the expansion continue forever or will it stop at some point in the future, causing the Universe to collapse? Our team — the High-z Supernova Search Team — was trying to answer this question when we were surprised to find that distant objects were further away than expected in a freely expanding Universe.
The High-Z Supernova Search Team was an international cosmology collaboration which used Type Ia supernovae to chart the expansion of the universe. The team was formed in 1994 by Brian P. Schmidt, then a post-doctoral research associate at Harvard University, and Nicholas B. Suntzeff, a staff astronomer at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. The original team first proposed for the research on September 29, 1994 in a proposal called A Pilot Project to Search for Distant Type Ia Supernova to the CTIO Inter-American Observatory. The original team as co-listed on the first observing proposal was: Nicholas Suntzeff (PI); Brian Schmidt (Co-I); (other Co-Is) R. Chris Smith, Robert Schommer, Mark M. Phillips, Mario Hamuy, Roberto Aviles, Jose Maza, Adam Riess, Robert Kirshner, Jason Spiromilio, and Bruno Leibundgut. The original project was awarded four nights of telescope time on the CTIO Victor M. Blanco Telescope on the nights of February 25, 1995, and March 6, 24, and 29, 1995.

NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

The pilot project led to the discovery of supernova SN1995Y. In 1995, the HZT elected Brian P. Schmidt of the Mount Stromlo Observatory which is part of the Australian National University to manage the team.

The team expanded to roughly 20 astronomers located in the United States, Europe, Australia, and Chile. They used the Victor M. Blanco telescope to discover Type Ia supernovae out to redshifts of z = 0.9. The discoveries were verified with spectra taken mostly from the telescopes of the Keck Observatory, and the European Southern Observatory.

In a 1998 study led by Adam Riess, the High-Z Team became the first to publish evidence that the expansion of the Universe is accelerating (Riess et al. 1998, AJ, 116, 1009, submitted March 13, 1998, accepted May 1998). The team later spawned Project ESSENCE led by Christopher Stubbs of Harvard University and the Higher-Z Team led by Adam Riess of Johns Hopkins University and Space Telescope Science Institute.

In 2011, Riess and Schmidt, along with Saul Perlmutter of the Supernova Cosmology Project, were awarded the Nobel Prize in Physics for this work.

The Supernova Cosmology Project is one of two research teams that determined the likelihood of an accelerating universe and therefore a positive cosmological constant, using data from the redshift of Type Ia supernovae.[1] The project is headed by Saul Perlmutter at Lawrence Berkeley National Laboratory, with members from Australia, Chile, France, Portugal, Spain, Sweden, the United Kingdom, and the United States.

The work for this project was carried out at the Wm Keck Observatory, Maunakea, Hawai’i, USA

Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

This discovery was named “Breakthrough of the Year for 1998” by Science Magazine and, along with the High-z Supernova Search Team, the project team won the 2007 Gruber Prize in Cosmology and the 2015 Breakthrough Prize in Fundamental Physics. In 2011, Perlmutter was awarded the Nobel Prize in Physics for this work, alongside Adam Riess and Brian P. Schmidt from the High-z team.
It appeared that they were somehow being pushed away…we had found that the Universe was not only expanding — it was accelerating! This means that not only is there normal matter in the Universe, but also another component that we cannot see, that pushes space apart. This unknown entity is now called dark energy.

Dark Energy Survey

Dark Energy Camera [DECam], built at FNAL

NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

Q. Half of the Nobel Prize went jointly to your team members Adam Riess and Brian Schmidt. Why were they the ones to receive the prize, and what was your role in the team?

A. Brian Schmidt was the team leader; he formed the team in 1994. Adam Riess collected most of the data in 1995 and 1996, which included information about the brightness of ten distant supernovae. Brian asked me to join the team to bring some ESO observing time…it’s hard to define what exactly every team member’s contribution was, but I worked a lot with the data that we gathered using ESO telescopes. I was also part of the discussions about the implications of the data.

Bruno Leibundgut at the Nobel celebration in Stockholm in 2011. Bruno was part of the winning team of the Nobel Prize in Physics, awarded for the discovery that the Universe is expanding at an accelerating rate. Credit: Jutta Tiemann

Q. Can you tell us about your week in Stockholm, where the Nobel Prize was awarded? What did you do while you were there? What was the atmosphere like?

A. It was an extremely full week! Aside from the award ceremony itself in Stockholm’s National Theatre, there was also a Nobel concert, attended by the Queen of Sweden, to which we were invited by the Nobel Prize winners. There were so many receptions and celebrations throughout the week, and it was even busier for the winners!

The winners, Adam Riess and Brian Schmidt, were very kind. They used their prize money to invite all of the team members, plus their partners, to the ceremony for the whole week. We even got to stay in the same fancy hotel as they did: the Grand Hotel in Stockholm.

Lots of our colleagues were there, including the other winning team, the Supernova Cosmology Project. The two teams had been in strong competition, because we were working towards the same result at the same time, sometimes even using the same instruments. That week, though, the competition fell away, because we were all winners and we had all contributed to this discovery. It was wonderful because we had the chance to discuss a lot, to talk about past experiences, things that occurred during the experiments. There was a lot of reminiscing and a lot of fun.

Q. What was the most special moment for you during the celebrations?

A. There were plenty of special moments, as the event is an incredible celebration of scientific research. One moment that stands out took place at the post-ceremony party. I bumped into Brian Schmidt, congratulated him and said: “Look, you’re a different person now, a certified genius!” He turned to me and said, “But Bruno, nothing will change between us.” And it’s true — now we meet less than once a year, but our relationship remains close.

ESO 1-metre Schmidt Telescope image of the Tarantula Nebula in the Large Magellanic Cloud. Supernova 1987A is clearly visible as the very bright star slightly to the right of the centre.
Credit: ESO

The ESO 1-metre Schmidt telescope at La Silla began its service life in 1971 using photographic plates to take wide-field images of the southern sky.

Q. What current questions in astronomy do you wish you knew the answers to?

A. Oh, there are so, so many! It would be wonderful to understand more about dark energy. What is it? Where does it come from? What’s the physical basis for it? We’re pretty much searching in the dark — literally! We haven’t really made progress in this field over the last ten years but we hope that with the Extremely Large Telescope [below], we will be able to shed light on this mystery.

Q. What do you love most about astronomy?

A. I love the detective work: the fact that you can work away at a problem for years, debate it with friends, look at it from different angles, and then suddenly you have a breakthrough and see something you’ve never seen before. I also love the ingenuity: the way that we have to devise our experiments without being able to touch our subjects. We can’t modify the sky or the stars: we just have to take them as they are, and employ our physical intuition to understand what we see.

One of the things I have focused on over the course of my career is Supernova 1987A, which I had the chance to see in the sky with my own eyes. Every time we look at it with the Very Large Telescope or the Hubble Space Telescope, we find something else unexpected — it’s amazing to be continually mesmerised by what this single object is doing. It’s beautiful because it’s an object that changes on the same timescale as a human lifetime, and it exploded at the beginning of my career. I look forward to seeing what else we can learn about it.

Sgr A* from ESO VLT

Biography Bruno Leibundgut

After a Physics degree and a PhD in Astronomy, Swiss astronomer Bruno Leibundgut found himself in the United States for two postdoctoral positions. Returning to Europe in 1993, Bruno started working at ESO in a group that defined how the VLT would be operated. After a couple of years he became Deputy VLT Programme Scientist, then in 1999 moved on to building up the data quality control group, connected to the archive. Bruno was Head of Office for Science for eight years, then Director for Science for six years, before closing the circle by becoming VLT Programme Scientist four years ago.

People@ESO shares stories of the people at ESO who are driving forward the world’s most advanced ground-based telescopes. Find more blog posts from guest bloggers and interviews with astronomers here on the ESOblog.

See the full article here .


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ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
•KUEYEN (UT2; The Moon ),
•MELIPAL (UT3; The Southern Cross ), and
•YEPUN (UT4; Venus – as evening star).
elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

ESO LaSilla
ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

ESO VLT 4 lasers on Yepun

ESO Vista Telescope
ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

ESO VLT Survey telescope
VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

ALMA Array
ALMA on the Chajnantor plateau at 5,000 metres.

ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres