Dr Roberto Trotta
r.trotta@ null imperial.ac.uk
Phone: +44 (0)20 7594 7793
Fax: +44 (0)20 759 47772
Imperial College London, Astrophysics, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK
There is no question that there is an unseen world.
The problem is, how far is it from midtown and how late is it open?
(Woody Allen)
I'm a cosmologist in the Astrophysics Group of Imperial College London, where I am a lecturer in physics. I am also a science communicator and I take part in numerous public engagement with science activities, from science festivals to radio broadcasts.
My research in cosmology is about analysing, interpreting and making sense of cosmological observations, in order to learn more about the properties and nature of dark matter and dark energy. I'm also interested in the early Universe and in developing connections between cosmology and particle physics. The goal is to learn more about the history and nature of the Universe, by using cosmology as a Universe-sized laboratory for particle and high energy physics.
Between 2005 and 2008 I have been the Lockyer Research Fellow of the Royal Astronomical Society at the Astrophysics Department of Oxford University. I've also been a Junior Fellow of St Anne's College. You can find more info about my academic background here. Or if you are into communication of science, then check out my outreach page.
What's new in the Universe?
(Last updated Dec 2011)
DarkAttack2012 / Ascona, Switzerland, 15-20 July 2012
For the past 80 years, astronomers have been wondering what exactly is responsible for the distribution of galaxies in the sky, and what drives the way they move about each other. Gravity as we know it, cannot explain this; not if visible matter is all there is to the Universe. Today, particle physics might be on the verge of finally unraveling this mystery.
Many physicists believe that the explanation for the behavior and structure of galaxies lies in the infinitely small scales of subatomic particle physics. A new type of particle, unlike any of the particles we know about, which does not emit nor absorb light, could be effectively invisible to the astronomers' instruments, yet make up most of the mass of the Universe. The detection of this new particle would shake up our understanding of the basics building blocks of the cosmos. The hunt for "Dark Matter" is on.
The Large Hadron Collider at CERN has begun testing some of the theories about Dark Matter. By colliding beams of particles at very high energy, this machine will re-create conditions that existed a fraction of a second after the Big Bang. Scientists believe that in this process Dark Matter particles will be produced. At the same time, other experiments (such as underground Dark Matter detector and satellites observing debris produced by Dark Matter collisions in the Universe) are being used to characterize the nature of Dark Matter, and to test whether its properties can explain the astronomers' puzzling observations.
This conference will bring together scientists looking for Dark Matter in particle physics, astrophysics and cosmology, in order to facilitate their collaboration and promote the exchange of new ideas across the different communities. This stimulating meeting will promote the development of a new, truly global approach to the discovery and characterization of Dark Matter, and help scientists to join forces in tackling one of the biggest unsolved mysteries of fundamental physics.
ADVANCED STATISTICS LECTURES / Copenhagen, Nov 14th-18th 2011
This elite PhD course in Copenhagen will provide the students with a wide overview of the most advanced statistical methods used for data analysis.
Data from experiments in high energy physics and observations in astrophysics demand nowadays a highly sophisticated statistical treatment. By inviting experts from both areas, we provide the students with the widest overview of the most advanced statistical methods. The course will cover the fundamental concepts of modern statistical data analysis, including examples derived from the two areas of science mentioned. The course is well suited and relevant for PhD students from a wide range of fields in Science, beyond the ones mentioned. The course will consist of lectures and practical problem- solving sessions (both calculations and computer exercises) and will last 5 full days.
Over the past two years I have been lucky enought to be collaborating with architect Julian Loeffler and artist Peter Liversidge, as part of an international team of scientists, architects and artists working towards exploring the concept of energy. This research cluster is coordinated and directed by the Architectural Association School of Architecture.
Our work, exploring the concept of potential energy with an impossible pinball machine, was shown at the 2010 Venice Architectural Biennale, at the Architectural Association School of Architecture, Bedford Square, London in May 2011.
It is currently on show at the Milano Triennale until June 26th.
To learn more, visit our AA Beyond Entropy blog.
Bayesian Methods in Cosmology: The Book
In recent years cosmologists have advanced from largely qualitative models of the Universe to precision modelling using Bayesian methods, in order to determine the properties of the Universe to high accuracy. This timely book is the only comprehensive introduction to the use of Bayesian methods in cosmological studies, and is an essential reference for graduate students and researchers in cosmology, astrophysics and applied statistics. The first part of the book focuses on methodology, setting the basic foundations and giving a detailed description of techniques. It covers topics including the estimation of parameters, Bayesian model comparison, and separation of signals. The second part explores a diverse range of applications, from the detection of astronomical sources (including through gravitational waves), to cosmic microwave background analysis and the quantification and classification of galaxy properties. Contributions from 24 highly regarded cosmologists and statisticians make this an authoritative guide to the subject.
BIG QUESTIONS DEBATE SERIES / Imperial College London
Imperial College London Astrophysics presents a new series of debates entitled The Big Questions on topical themes in modern astrophysics and cosmology. In each debate, a member of the Astrophysics Group will discuss one of the big questions raised by cutting-edge research with a guest. The debates are aimed at the general public, who will have the opportunity to ask questions in what will be a lively and interactive discussion.
- 21 January 2010, 7-9pm: The Arabic roots of modern astronomy. Dr Rim Turkmani and Professor Jim Al-Khalili OBE
- 12 November 2009, 6.30-8.30pm: Human spaceflight: Science or spectacle? Dr David Clements vs Dr Ian Crawford
- 15 September, 6-8pm: Universe or Multiverse? Dr Roberto Trotta vs Prof. Bernard Carr
- 21 July 2009, 6-8pm: The fate of the Universe: does dark energy really exist? Prof. Andrew Jaffe vs Prof. Subir Sarkar
- 18 June 2009, 6-8pm: The origin of the Universe. Prof. Michael Rowan-Robinson vs Rev. Dr John Polkinghorne, KBE, FRS
These debates are free with registration in advance. Further information and registration here.
COSMOSTATS09 / Ascona, Switzerland, July 26th-31st 2009
In the last ten years, a wealth of observational data has revolutionized cosmology. The purpose of this workshop is to bring together world-class leading figures in cosmology, particle physics and from the statistical community in order to exchange knowledge and experience in dealing with large and complex data sets, and to meet the challenge of upcoming large cosmological surveys.Furthermore, CosmoStats09 will host the GRavitational lEnsing Accuracy Testing 2008 (GREAT08) Challenge Final Workshop.
BBC RADIO 3 / Future Generation Thinkers
You can listen here to a BBC Radio 3's "Future Generation Thinkers" programme (which aired on Nov 7th 2008) where I discuss dark energy and the place of humankind in the cosmos.
MICHELSON LECTURES / CWRU Michelson Prize Lectures
In May 2008 I gave the 2008 Michelson Prize Lectures series at case Western Reserve University (Cleveland). You can find the pdf's of the talks below.
May 5th: Bayes in the sky - Advanced statistical tools for cosmology
May 6th: Probing dark energy with cosmology
May 7th: Precision cosmology for the 21st century
May 9th: Astrophysical probes of dark matter
REVIEW ARTICLE / Bayes in the sky: Bayesian inference and model selection in cosmology
An invited review for Contemporary Physics
Abstract: The application of Bayesian methods in cosmology and astrophysics has flourished over the past decade, spurred by data sets of increasing size and complexity. In many respects, Bayesian methods have proven to be vastly superior to more traditional statistical tools, offering the advantage of higher efficiency and of a consistent conceptual basis for dealing with the problem of induction in the presence of uncertainty. This trend is likely to continue in the future, when the way we collect, manipulate and analyse observations and compare them with theoretical models will assume an even more central role in cosmology.
This review is an introduction to Bayesian methods in cosmology and astrophysics and recent results in the field. I first present Bayesian probability theory and its conceptual underpinnings, Bayes' Theorem and the role of priors. I discuss the problem of parameter inference and its general solution, along with numerical techniques such as Monte Carlo Markov Chain methods. I then review the theory and application of Bayesian model comparison, discussing the notions of Bayesian evidence and effective model complexity, and how to compute and interpret those quantities. Recent developments in cosmological parameter extraction and Bayesian cosmological model building are summarized, highlighting the challenges that lie ahead.
SUPERSYMMETRY PHENOMENOLOGY / SuperBayeS package
SuperBayeS is a software for fast and efficient Markov Chain Monte Carlo sampling of supersymmetric theories. It allows to explore multidimensional SUSY parameter spaces and to compare SUSY prediction with observable quantities, including sparticle masses, dark matter abundance, direct and indirect detection quantities and much more. The current release implements an even more efficient scanning technique, called MultiNest.
PHYSICS AND PHILOSOPHY / Probing the arche-fossil
A conversation with the philosophical magazine COLLAPSE, centering around dark matter and the ontological perspective coming from the empirical study of `ancestral phenomena' in the history of the Universe.