Extra seminars, which can be organised by anyone in the group separately from the colloquium series, are also included on this page for convenience.
To view a talk abstract, click on the talk title. Click again on the talk title to hide the abstract.
| Date | Speaker | Topic |
|---|
| Sep 15 |
Special Seminar - Yacine Ali-Haimoud
(JHU, Baltimore) |
A thing or two about primordial black holes |
| TBD |
| Sep 21 |
Quentin Parker
(HKU, Hong Kong) |
Late Stage Stellar Evolution Research at HKU |
| In this mixed content colloquium I cover various aspects of our groups research into late stage stellar evolution using at its hear the new H*A*S*H (Hong/Kong/AAO/Strasbourg H-alpha) Planetary Nebulae research platform. Some of our recent research results will be summarised together with future plans. |
| Oct 5 |
Catherine Heymans
(IfA, Edinburgh) |
Cosmology with KiDS |
| I will present the first cosmological parameter constraints from the Kilo Degree Survey (KiDS), an ongoing ESO survey that studies the growth of structures and the expansion history of the Universe using weak gravitational lensing. Interestingly our analysis finds a low-redshift universe that is rather different from the predictions of the Planck CMB experiment.I will discuss whether this tension could arise from systematic uncertainties in either probe, or whether it is evidence for a Universe that is more exotic than the standard LambdaCDM model. |
| Oct 12 |
Schuster Colloquium - Tetsuo Hatsuda
(RIKEN Nishina Center for Accelerator-Based Science, Japan) |
From Quarks to Neutron Stars |
| A neutron star weighs about the same as our Sun, while its radius is only about 10km. The neutron star surface is a solid, while its interior is a liquid mostly made of neutrons. The composition of the deep interior is still unknown but it could be made of quarks. After introducing the standard model of elementary particles and the theory of strong interaction between quarks, we will discuss the current understanding of the structure of neutron stars in terms of quarks and other elementary particles. We will also discuss how observations of neutron stars can provide information about their internal structure. |
| Oct 19 |
Dr Christopher Wallis
(UCL) |
Mapping on the sphere: applications in cosmology |
| Part 1:
We develop techniques to solve ill-posed inverse problems on the sphere by sparse regularisation, exploiting sparsity in both axisymmetric and directional scale-discretised wavelet space. Denoising, inpainting, and deconvolution problems, and combinations thereof, are considered as examples. Inverse problems are solved in both the analysis and synthesis settings, with a number of different sampling schemes. The most effective approach is that with the most restricted solution-space, which depends on the interplay between the adopted sampling scheme, the selection of the analysis/synthesis problem, and any weighting of the l1 norm appearing in the regularisation problem. More efficient sampling schemes on the sphere improve reconstruction fidelity by restricting the solution-space and also by improving sparsity in wavelet space. We apply the technique to denoise Planck 353 GHz observations, improving the ability to extract the structure of Galactic dust emission, which is important for studying Galactic magnetism.
Part 2:
We examine mass mapping on the sphere for current and future weak lensing (WL) experiments. With areas of sky observed in WL experiments increasing, the curvature of the sky must be taken into account when making mass maps. We present some preliminary work demonstrating mass mapping on the sphere and through simulations show what size of patch of sky the curvature of the sky becomes important. We apply these techniques to make preliminary mass maps on the sphere using the publicly available DES science verification data. |
| Oct 26 |
Marco Pignatari
(University of Hull) |
The art of baking coinage metals in stars |
| The origin of precious coinage metals like copper, gold or silver is full of mystery. Today we know that copper is mostly made by massive stars, before the star explode as supernova. But the origin of copper was controversial for a long time, and the solution came only from modern nuclear physics experiments. Gold is made instead by rapid neutron captures (defined as r process) in stellar explosions. Several astrophysical scenarios have been explored, but there are no definitive answers after decades of research. Silver is even more puzzling: today it is not known how most of the silver observed in nature was made.
In this seminar I will explore the production of these three coinage metals in stars, and the relevant source of uncertainties affecting our analysis. I will present what we know about them, and the puzzles that are still left to be solved. |
| Nov 2 |
Marten van Kerkwijk
(University of Toronto, Canada) |
Pulsar Scintellometry: using the interstellar medium to elucidate where giant pulses arise |
| The interstellar medium scatters pulsar radiation, which results in multiple images in which radiation arrives at slightly offset angles and with small time delays. As a result, shorter radio pulses are scatter broadened and longer ones scintillate. I will briefly describe how we hope to use scintillation to do nano arcsecond astrometry, in particular of pulsar binaries. Next, I will describe concrete results obtained so far, from using giant pulses, both of the black widow pulsar, PSR B1957+20, and the Crab pulsar, to measure the screen's impulse response function. For PSR B1957+20, we find that giant pulses that occur close in time share the same scattering function and that, as expected, they decorrelate on the scintillation timescale. From close pairs of giant pulses, we infer that the intrinsic duration is very short, at most 200 ns. For the Crab pulsar, however, we find that even giant pulses that occur in the same rotation are not correlated. This suggests that the pulses arise in regions sufficiently far apart that they are resolved by the scattering screen. This is very difficult to understand for any model in which the emission arises inside the light cylinder radius. |
| Nov 10 |
Special Seminar - Giovanni Cabass
(University of Rome, Italy) |
CMB Spectral Distortions: A Window on Inflation at Small Scales |
| Deviations from a black-body CMB spectrum that arise from dissipation of density perturbations can constrain the primordial scalar spectrum at scales from 50 to 10^4 Mpc^-1, inaccessible to CMB anisotropies and large-scale structure measurements.
I present the implications of a PIXIE-like experiment that would measure mu- distortions at a level of (1/n) x 10^-8. A sensitivity of about 3x PIXIE will imply a guaranteed discovery: mu-distortion is detected or a positive running of the spectral index is excluded, both at 95% CL or higher (arXiv:1602.05578). When the running of the running is included, PIXIE itself will improve the bounds on it by ~80% (arXiv: 1605.00209).
Finally, I discuss mu-distortions as a probe of non-Gaussianity in the squeezed limit, and touch briefly on the issue of gauge artifacts (projection effects) when connecting to late time observations. |
| Nov 16 |
Elisa Chisari
(Oxford U., UK) |
Intrinsic alignments of galaxies |
| The intrinsic correlations of galaxy shapes are a recognised contaminant to weak gravitational lensing measurements. Luminous red galaxies have been observed to point radially towards each other, likely as a consequence of the action of the tidal field of the large-scale structure on their shapes and orientations; blue, disc-like galaxies are thought to be subject to no detectable alignment. If these intrinsic alignments are not accounted for, cosmological constraints from future surveys could be severely biased. I will describe the exploration of the intrinsic alignment signal in cosmological hydrodynamical simulations, in preparation for future weak lensing surveys. I will also discuss how intrinsic alignments might become themselves a cosmological probe in the future, helping us constrain the physics of inflation. |
| Nov 23 |
Anthony Challinor
(IoA Cambridge, UK) |
From large-scale structure to inflation: lensing of the cosmic microwave background |
| Weak gravitational lensing by the large-scale clustering of matter subtly distorts the temperature and polarization anisotropies of the cosmic microwave background (CMB). These distortions imprint the CMB with information on the late-time expansion, geometry, and clustering that would otherwise be inaccessible with the primary fluctuations alone. In this talk, I will review the tremendous progress that has been made in recent years in observing the predicted effects of lensing in the CMB and discuss applications of this new cosmological probe. In particular, I will discuss recent Planck lensing results, which firmly establish CMB lensing as a precision probe of late-time clustering. Lensing is also a source of confusion when attempting to constrain primordial gravitational waves from inflation with B-mode polarization. I will end by discussing recent demonstrations of delensing, whereby one attempts to undo the effects of lensing to clean-up our view of the primordial CMB signals. Delensing will soon become critical for high-sensitivity B-mode searches for primordial gravitational waves. |
| Nov 30 |
Nick Wright
(Keele University) |
The Dynamics of Star Clusters |
| The formation and evolution of young star clusters is fundamental to our understanding of the star formation process, the conditions faced by young binary and plenty systems, and the formation of long-lived open and globular clusters. Despite this our understanding of the physical processes that drive this evolution has been limited by the static nature of most observations. This is all changing thanks to a revolution in kinematic data quality from large-scale radial velocity surveys and new astrometric facilities such as Gaia. I will present results from structural and kinematic studies of star clusters that constrain their past dynamical evolution. I will talk about recent kinematic observations of the massive OB association Cygnus OB2 that show it has considerable kinematic substructure and no evidence for the radial expansion pattern predicted by theories such as residual gas expulsion. This means that, contrary to the standard view of OB associations as expanded star clusters, Cygnus OB2 could never have been a dense star cluster in the past. This places strong constraints on the frequency of clustered vs non-clustered star formation and the origin of star clusters and OB associations. |
| Dec 7 |
Schuster Colloquium - Sergey Bozhevolnyi
(The University of Southern Denmark) |
Nanophotonics: Light on Nanoscale |
| Interaction of light with nanostructured materials gives rise to nanostructured optical waves, i.e., to electromagnetic fields varying strongly at the nanoscale, opening exciting possibilities for surpassing the classical diffraction limit and molding the flow of light at length scales far below the optical wavelength. Using carefully designed nanostructures light can be manipulated in fascinating new ways that are impossible to achieve with natural materials and in conventional geometries. Controlling light at the nanoscale led to unveiling new physical phenomena and empowered many applications, including integrated optical circuitry, optical processing, super-resolution microscopy, quantum information technologies, bio- and medical sensing. In this talk, I will concentrate on arguably the most important mission of light - empowering communication and information technologies, and follow recent developments in exploiting metallic nanostructures for reaching ultimate miniaturization of optical circuitry. |
| Dec 14 |
Elaine Sadler
(CAASTRO, Australia) |
Neutral hydrogen in the distant Universe: first results from the Australian SKA Pathfinder telescope |
| Our knowledge about the amount and distribution of neutral hydrogen (HI) in galaxies in the distant Universe remains patchy and incomplete, yet this component of the interstellar medium is critical to understanding how galaxies evolve over cosmic time. In my talk, I will discuss how observations of the redshifted 21cm HI line, seen in absorption against bright radio continuum sources, can provide new information about the HI content of distant galaxies and the role of cold gas in AGN fuelling and feedback processes.
The large field of view, wide spectral bandpass and radio-quiet site of the Australian SKA Pathfinder (ASKAP) radio telescope provide a powerful new capability for HI absorption studies of galaxies in the redshift range 0 < z < 1. I will show a range of encouraging results from a pilot survey of 100 bright radio sources we have recently carried out with a small test array during ASKAP commissioning, and discuss some of the interesting challenges they pose for the astrophysical interpretation of HI absorption-line data. I will also outline the exciting prospects for the much larger studies that will soon be possible with ASKAP (and in future with the SKA). |
| Jan 25 |
Thomas Tauris
(University of Bonn, Germany) |
Formation of Double Neutron Stars |
| In recent years, the discovery rate of double neutron star (DNS) systems has increased rapidly and the coming decade will greatly enhance the number of both radio pulsar DNS systems, with the completion of the Square-Kilometre-Array, and DNS mergers from detections of high-frequency gravitational waves using LIGO. This calls for a new investigation of the formation and evolution of DNS systems. In this talk, I will review the exotic journey of binary stars leading to the production of DNS systems with a focus on various aspects of stellar physics, binary interactions, supernova (SN) explosions and accretion processes. In particular, I will discuss correlations between spin period (of the first-formed, mildly recycled NS), orbital period and eccentricity, based on theoretical modelling. Finally, I will discuss NS kicks and present a large set of Monte Carlo simulations of the second SN in order to extrapolate the pre-SN stellar properties and probe the explosions. In a few cases, we are able to obtain unique pre-SN parameters (e.g. for the double pulsar PSR J0737-3039). |
| Jan 27 |
Special Seminar - Natasha Hurley-Walker
(ICRAR, Australia) |
The GaLactic and Extragalactic All-sky MWA (GLEAM) survey |
| I present the first all-sky low-frequency radio source catalogue from the SKA_Low precursor, the Murchison Widefield Array: more than 300,000 sources are detected down to a flux density limit of ~50 mJy, for nearly all of the sky south of Declination +30deg. Using novel source-extraction techniques, flux density measurements are made across a bandwidth of 72--231 MHz, with a flux scale accuracy of better than 10%. I will discuss the challenges inherent in performing a large area sky survey with a new aperture array telescope, present the catalogue and associated images, and discuss some of the upcoming science based on these data, such as finding cluster relics and haloes, and understanding the births and deaths of AGN. |
| Feb 1 |
Dr Chris Clarkson
(QMUL, UK) |
Roulettes: A weak lensing formalism for strong lensing |
| I will present a new perspective on gravitational lensing. I will discuss a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the non-linear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. An image distorted by a generic lens may be constructed as a sum over `roulettes', which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, shear and flexion of weak lensing to arbitrary order, and provides a unified bridge between the strong and weak lensing regimes. |
| Feb 7 |
Special Seminar - Kendrick Smith
(Perimeter Institute, Canada) |
Searching for fast transients with CHIME |
| CHIME is a new interferometric telescope at radio frequencies 400-800 MHz, scheduled for first light this summer. Its mapping speed is among the highest of any radio telescope in the world, making it a very powerful search machine for transients. I'll describe its current status, with emphasis on algorithms being developed to search for fast radio bursts and pulsars. |
| Feb 15 |
Schuster Colloquium - Julia Tjus
(Ruhr Astroparticle and Plasma Physics Center, Germany) |
Searching for the origin of Galactic cosmic rays: The multimessenger
approach |
| High-energy cosmic rays play an important role for the ISM through heating processes and plasma instabilities that can create and govern large-scale magnetic fields. To understand their origins is essential in order to allow for a full and proper theoretical modelling of processes in the ISM.
The search for the sources of high-energy cosmic rays has made significant progress the past decade. By including multimessenger methods, the general picture of the presence of a Galactic component at low energies and an extragalactic one at the highest energies has been strengthened. Yet, unambiguous proof of the exact origins of cosmic rays is missing. In this talk, the current scientific status on Galactic cosmic rays sources from theory and experimental data is summarised. In particular, the focus of this talk lies on the search for photon, neutrino and charged cosmic ray signals from the Galaxy and their theoretical interpretation in the context of the quest for the origin of high-energy cosmic rays. The use of multiwavelength data, from radio to TeV energies, in combination with pieces of information from high-energy neutrinos as detected with IceCube, and cosmic ray data are discussed. Finally, the prospect to unambiguously identify Galactic cosmic ray sources within the next decades are presented. |
| Feb 23 |
Dr Elisabetta Valiante
(Cardiff) |
The Herschel-ATLAS survey: main results and data release |
| Abstract I describe the first major data release of the largest single key-project carried out in opentime with the Herschel Space Observatory. The Herschel Astrophysical Terahertz Large Area Survey(H-ATLAS) was a survey of 600 deg^2 in five photometric bands: 100, 160, 250, 350 and 500 micron. In this talk I will show some of the results of the survey: 1) the development of a technique to select lensed objects with 100% efficiency, 2) how to select up to 1000 lensed sources, 3) the development of a technique to select very high redshift galaxies, 4) the discover of a high-redshift proto-cluster, 5) the definition of the local far-ir luminosity function, 6) dust properties of nearby galaxies. Moreover, I will describe images and catalogues of the three fields on the celestial equator, previously observed in the Galaxy and Mass Assembly (GAMA) redshift survey, which cover a total area of 161.6 deg^2. These data have been released and made available to the public during 2016. The released catalogue include ~10^5 sources detected at 4 sigma at 250, 350 and 500 micron.
Host: Jens Chluba |
| Mar 1 |
Dr Adam Amara
(ETH Zurich, Switzerland) |
Integrated View of Cosmology: Do the Pieces Fit Together? |
| Abstract: Cosmology offers us a way of seeking and understanding fundamental physics beyond what we can access in our laboratories. Measurements to date have revealed the presence of several phenomena that cannot be explained within the standard model of physics, including dark energy and dark matter. These now form two of the key pillars of the LCDM model, which has become our standard model in cosmology. In this talk, I will give a quick summary of recent progress in the field. As part of this, I will highlight the remarkable successes of LCDM in explaining a wide array of observational evidence coming from recent experiments. I will also discuss the potentials for new discoveries in galaxy surveys, with a focus on gravitational lensing, the on-going Dark Energy Survey (DES) and future galaxy surveys, such as the LSST. Together, these experiments will allow us to truly enter the precision measurement era for the late-time Universe.
Host: Sarah Bridle |
| Mar 8 |
Fabian Schmidt
(MPA Garching, Germany) |
Probing the Primordial Universe with Galaxy Clustering and Shapes |
| Abstract: One of the primary goals of cosmology is to elucidate the origin of
structure in the Universe. The currently most widely accepted paradigm is the theory of inflation - an epoch of extremely rapid expansion at a very early phase in the history of the Universe. A significant effort in cosmology is directed toward testing this hypothesis. I will show how we can use the clustering of galaxies, as well as statistics of their observed shapes, to learn about the physics of inflation, as well as alternative scenarios. This provides a fascinating connection between the largest observable scales in the cosmos and physics at energies far beyond the reach of accelerators on Earth.
Host: Jens Chluba |
| Mar 15 |
Schuster Colloquium - Dr Stefan Soldner-Rembold
(The University of Manchester) |
The Deep Underground Neutrino Experiment (DUNE) |
| The outstanding imaging capability of liquid-argon Time Projection Chambers makes them one of the most promising technology choices for next-generation neutrino experiments. Within a decade, the DUNE experiment in South Dakota, using 40-ktons of liquid argon, will start to address a broad science programme. Primary science drivers are the discovery of a possible matter-antimatter asymmetry (CP violation) in the neutrino sector, the detection of neutrinos from supernovae, and the search for proton decay as predicted by Grand Unified Theories. Several mid-size detectors at Fermilab and CERN will soon demonstrate the potential of the liquid-argon technology, searching for sterile neutrinos and measuring liquid-argon interactions of neutrinos and charged particles. I will give an overview of the current status and future discovery potential of liquid-argon detectors. |
| Mar 22 |
Alexander Schekochihin
(University of Oxford) |
Stratified Turbulence, Turbulent Heating and Magnetic Fields in Galaxy Clusters |
| Galaxy clusters are the largest basic units in which matter clumps together in the Universe. We observe them via X-ray emission of the hot, ionised gas (plasma) that makes up most of their visible mass (which is gravitationally confined within the potential well associated with the much more massive dark-matter component). Clusters are believed to be self-regulated (thermo)dynamical systems: gas within them accretes onto the central black hole, whose ejecta then stir up and reheat the cluster gas, accounting for a seemingly universal (or near-universal) profile of temperature that is observed. How this heating occurs, i.e., how the ionised gas in clusters maintains its very high X-ray emission temperature has been a longstanding problem in theoretical astrophysics --- and, indeed, the heating problem extends to hot dilute gases in many other astrophysical environments as well. I will present a view of this problem based on attributing the heating of the gas to the dissipation of internal waves and mechanically stirred turbulence in a stratified cluster plasma. I will first outline how a turbulence theoretician might think of this turbulence and then show how an X-ray observer might use --- and indeed has used [1] --- these ideas to show that turbulence can indeed be the heating channel in cluster cores. While at the time when these measurements were done, turbulence could only be probed indirectly, via density fluctuations [1,2], new information is now available: before the loss of the X-ray satellite Hitomi, the instrument was able to carry out a study of the Perseus Cluster, directly measuring (via line widths) the turbulent velocities in a galaxy cluster for the first time. These were precisely of the right order of magnitude for the turbulent heating to maintain the cluster gas against radiative losses. If I have time, I will then explain how some interesting plasma microphysics of the intracluster medium (plasma-beta-dependent thresholds for instabilities driven by pressure anisotropies arising from the plasma being magnetised and turbulent) can help us infer magnetic fields in clusters (this should excite those who prefer radio to X-ray) and also give us confidence that turbulent heating produces thermally stable (observed) temperature profiles [3] (some further theoretical support for such models arises from the recent realisation that high-beta plasma dynamics in weakly collisional environments are radically different from what one expects via one's acquired MHD intuition and possibly provides a very efficient heating channel for turbulent motions [4,5]).
Hosts: Philippa Browning, Grigory Vekstein |
| Mar 29 |
Jason McEwen
(MSSL) |
Next-generation radio interferometric imaging for the SKA era |
| Future telescopes, such as the Square Kilometre Array (SKA), will usher in a new big-data era for radio interferometry. Sparse regularisation techniques motivated by compressive sensing have emerged recently as a powerful approach for imaging radio interferometric images in this big-data era. While compressive sensing techniques have shown promise for some time, the majority of prior work has been restricted to simulations. We show recent results of applying compressive sensing imaging techniques to data from the Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA), recovering images that have a significantly improved dynamic range compared to those recovered by CLEAN. More importantly, we show how these techniques can be scaled to extremely large data-sets by leveraging an algorithmic structure where both computations and data can be highly distributed. Nevertheless, standard compressive sensing approaches recover point estimators only and uncertainty information is not quantified. We show how the sparse priors of compressive sensing approaches, which have been shown in practice to be highly effective, can be integrated in a statistical framework so that error information can be estimated.
Host: Anna Scaife |
| Apr 27 |
Special Seminar - Dr Federico Urban
(KBFI) |
Heavier and darker: spin-2 dark matter |
| The ghost-free massive spin-2 field of bigravity turns out to be a very perfect Dark Matter candidate. I will review the theoretical foundations of bigravity, and outline the qualities and phenomenology of spin-2 gravitational dark matter.
Host: Richard Battye |
| May 3 |
Dr Ken Chen
(National Astronomical Observatory of Japan) |
Lighting Up the Universe with the First Cosmic Explosions |
| One of the paramount problems in modern cosmology is to elucidate how the first generation of luminous objects, stars, supernovae, and galaxies shaped the early universe at the end of the cosmic dark ages. According to the modern theory of cosmological structure formation, the hierarchical assembly of dark matter halos provided the gravitational potential wells that allowed gas to form stars and galaxies inside them. Modern large telescopes have pushed the detection of galaxies up to a redshift of z ~ 10. However, models of the first luminous objects still require considerable effort to reach the level of sophistication necessary for meaningful predictions, Due to the complexity of involved physical phenomena, this physical understanding may only come by the proper use of numerical simulations. Therefore, I have used state-of-the-art simulations on some of largest supercomputers to study these objects. In my talk, I will discuss the possible physics behind the formation of these first luminous objects by presenting the results from our simulations. I will also give possible observational signatures of the cosmic dawn that will be the prime targets for the future telescopes such as the James Webb Space Telescope (JWST). |
| May 10 |
Schuster Colloquium - Dr Gerry Agnew
(Rolls-Royce) |
Combining fuel cells with gas turbines |
| Abstract TBD |
| May 11 |
Special Seminar - Dr Steve Croft
(University of California, Berkeley, USA) |
Breakthrough Listen: Expanding the Search for Life Beyond Earth |
| The $100M, 10-year philanthropic "Breakthrough Listen" project is driving an unprecedented expansion of the search for intelligent life beyond Earth. Modern instruments allow ever larger regions of parameter space (luminosity, duty cycle, frequency coverage) to be explored, which will enable us to place meaningful physical limits on the prevalence of transmitting civilizations. Data volumes are huge, and preclude long-term storage of the raw data products, so real-time and machine learning processing techniques must be employed to identify candidate signals as well as simultaneously classifying interfering sources. However, the Galaxy is now known to be a target-rich environment, teeming with habitable planets. Data from Breakthrough Listen can also be used by researchers in other areas of astronomy to study pulsars, fast transient sources, or a range of other science targets.
Breakthrough Listen is already underway in the optical and radio bands, and is also engaging with facilities across the world, including Square Kilometer Array precursors and pathfinders, to explore the pathway to SETI science with SKA. I will discuss the technology, science goals, data products, and roadmap of Breakthrough Listen, as we attempt to answer one of humanity's oldest questions: Are we alone?
Host: Mike Garrett |
| May 17 |
Dr Caterina Tiburzi
(University of Bielefeld, Germany) |
Pulsars as probes of the low-frequency gravitational sky |
| Pulsars are invaluable laboratories to test gravity theories. The aim of Pulsar Timing Array (PTA) experiments is to exploit the clock-like behaviour of an array of carefully selected millisecond pulsars to detect gravitational waves at low frequencies. In the last decade, three PTA experiments were started. These three experiments, based on the most sensitive radio telescopes in the world, developed detection algorithms and refined the timing precision pushing the sensitivity of PTAs lower and lower. Although no gravitational wave detection has been made to date, the future perspectives are more than exciting thanks to new, futuristic radio telescopes coming online in the next years, such as the Five hundred Aperture Spherical Telescope and, in particular, the Square Kilometre Array.
Host: Rene Breton |
| May 18 |
Special Seminar - Dr Jon Gudmundsson
(University of Stockholm, Sweden) |
Early results from the SPIDER experiment |
| Abstract: SPIDER is a balloon-borne experiment designed to image the polarization of the cosmic microwave background with the aim of constraining models of the early universe. SPIDER was launched on January 1, 2015 and successfully completed a 17-day flight across Antarctica. A subsequent flight is scheduled for December 2018. I will briefly review the experiment, present early results from from SPIDER's first flight, and discuss the implications for future ballooning and satellite missions.
Host: Jens Chluba |
| May 24 |
Schuster Colloquium - Prof Sarah Bridle
(University of Manchester) |
From astrophysics to agriculture |
| There is an impending perfect storm of pressure on our food production system, with increasing population and changing consumer tastes, in the face of rising temperatures and extreme weather events. Tim Gore, head of food policy and climate change for Oxfam, said "The main way that most people will experience climate change is through the impact on food: the food they eat, the price they pay for it, and the availability and choice that they have.". Yet, at the same time, food production is a bigger contributor to climate change than transport. This is why I am leading the new STFC Food Network+ which aims to engage STFC researchers (astro/particle/nuclear physics) and STFC facilities (e.g. Diamond) to apply their capabilities to food, from agriculture, supply chain to nutrition and consumer choice. In this talk I will describe some of the challenges in food research and how physicists can help.
Might you be interested in doing a PhD on image analysis in agriculture from October? If so please get in touch and/or come along to chat and eat free pizza from 11.45am in the Lovell Seminar room just before the talk. Please sign up to guarantee your pizza here https://doodle.com/poll/ayybpfhswpewp2p4 |
| May 24 |
Ilya Mandel
(University of Birmingham) |
Beautiful binaries |
| The first detections of gravitational waves from binary black hole mergers have opened up new opportunities and challenges in astrophysics. I will describe my group's efforts to extract the astrophysical evolution of massive stellar binaries from observations of gravitational waves emitted during mergers of stellar remnants.
Time permitting, I will also discuss the promise of double tidal disruptions of stellar binaries by massive black holes to explain some very intriguing observational signatures from galactic nuclei.
Host: Rene Breton (see meeting requests to him) |
| May 31 |
Dr Caitriona Jackman
(University of Southampton) |
Adventures in the Outer Solar System |
| There has never been a better time to study the gas giant planets Jupiter and Saturn. The Cassini mission is executing its "Grand Finale" orbits after more than a decade at Saturn, while the Juno spacecraft is on a daredevil tour of Jupiter. I will show key results from these missions and outline the open questions that they have raised. My research focus is planetary magnetospheres so I will give an insight into how we study the dynamics of the magnetic and plasma environments of these huge systems. I will discuss the need for analysis techniques such as machine learning to deal with the vast amounts of complex data currently available to us. I will also show an example of how magnetospheric physics and astronomy meet through the examination of Jupiter's X-ray emission. The talk will be aimed at a general astronomical audience with the main aim to show you all how amazing Jupiter and Saturn are! |
