Immediately after each JBCA Colloquium there is normally a "Meet the Speaker" session, where students have the chance to chat with the colloquium speaker about their talk or more generally about their subject area. This session is for students only.
To view the abstracts for a talk, click on their title. Click again on their title to hide them.
| Date | Speaker | Topic |
|---|
September 28th
Tuesday at 2pm |
Paola Andreani
(ESO) |
Protocluster candidates and physics of the intergalactic medium: my scientific interests in ALMA |
| No abstract available! |
| October 6th 2010 |
Dr. Jaime Pineda
(JBCA, Manchester) |
How are low-mass stars formed? Just remove the turbulence! |
| Low-mass stars are formed in the densest and coldest regions inside Molecular Clouds called "Dense Cores." It is in these Dense Cores where we can study the initial conditions needed for star formation and also the early stages of star formation. However, the formation of dense cores out of the original molecular cloud is not understood, moreover, the way these dense cores are connected to the environment is completely unknown. Here we present the detection for the first time of the transition between gas with supersonic and subsonic turbulence in a single tracer , using large scale NH3 maps observed with the GBT. These results provide a great opportunity to study both, the formation process of dense cores, and the initial stages of collapse. We finally show how to us these results to place constraints on the different theories of star formation. |
| 20th |
Prof. Yvonne Elsworth
(Birmingham) |
Schuster Colloquium - The solar-stellar connection and looking for good vibrations |
| No abstract available! |
| 27th |
Scott Chapman
(Cambridge) |
Completing our understanding of high redshift ULIRGs: superwind outflows, a Herschel census, and the South Pole Telescope extremes of the population. |
| Studying ultraluminous galaxies (ULIRGs) at early times (z>2) has become a relatively mature science. However there remain various aspects of this field that are still mired in uncertainty. I will present three avenues of research into high-z ULIRGs which are significantly pushing our understanding of the population.
- The South Pole Telescope (SPT) has recently discovered a population of extraordinarily bright, dusty, star-forming galaxies in a mm-wave survey of the southern sky (Vieira+2010). Our followup studies (with the VLT, SMA, ATCA, and Spitzer) suggest that these sources are genereally high-redshift (z > 2), strongly-lensed, sub-mm galaxies (SMGs), allowing for the potential of detailed astrophysical study. There are also rare examples of SMGs at the extremes of luminosity function, pushing the limits of our understanding of luminous star bursts. This population will be key for exploiting early science with ALMA.
- Herschel has offered the possibility for selecting high-z ULIRGs without dust temperature bias. I present work with SPIRE (250-500micron), following up established populations of millimetre-bright and -faint radio sources at z~2-3, and the implications for the census and evolution of distant activity.
- We have undertaken an absorption line study of ~60 high-z ULIRGs at z=1-3 in order to characterise outflow properties in this sample. The highest luminosity ULIRGs show a flattening off in outflow velocity with increasing SFR and many of them have wind velocities less than the escape velocity of the galaxy. This suggests that such systems evolve in a positive feedback mode and have less of an impact on the evolution of the IGM than their lower luminosity counterparts.
|
| November 3rd |
Mike Cruise
(Birmingham) |
The potential for Very High Frequency Gravitational Wave science |
| The search for gravitational waves is one of the major challenges in current day physics. It is appropriate that the current detectors for gravitational waves target frequencies in the milliHertz to kilohertz range where massive black holes and neutron stars may be expected as sources. If gravitational wave astronomy follows the path of electromagnetic astronomy then other frequency bands will need to be opened, especially those at high frequencies. This talk will describe experiments already underway to develop gravitational wave detectors for very high frequencies, using interactions with electromagnetic fields. Detectors operating at GHz and optical frequencies will be described together with the possible sources they may detect. |
| 10th |
Prof. Terry Sloan
(Lancaster) |
Schuster Colloquium - Cosmic rays, climate and the origin of life |
| The Colloquium will cover three topics: an overview
of what we know about cosmic rays; a summary of the
standard picture of how man-made emissions of greenhouse
gases could be affecting the Earth's climate; and a brief
overview of how it is thought that life started on Earth.
I will go on to explore possible interconnections among
these three topics. |
| 17th |
Hiranya Peiris
(UCL) |
Fingerprints of the early universe |
| The observed properties of the primordial fluctuations in the cosmic microwave background (CMB) can provide constraints on physical theories in regimes otherwise inaccessible to experiment. A "concordance" picture of nearly-scale-invariant, adiabatic, Gaussian fluctuations obeying statistical isotropy and homogeneity has emerged in recent years. I will summarize recent progress in testing with CMB data the inflationary hypothesis for describing the very early universe, and the advances we can expect in the near future.
|
| 24th |
Jacco van Loon
(Keele) |
Using stars as probes of the structure and evolution of galaxies |
|
- Star formation history and dust production in the centre of M33;
- The extra-planar gas of the Milky Way.
Stars trace the star formation history of the galaxy they inhabit, as well as its sub-structures such as spiral arms and central bulges. Stars also play a role in sustaining star formation. Furthermore, stars can be used as torches shining through the intervening interstellar medium. I present results from two of my recent research programmes: (1) using pulsating red giant and supergiant stars to reconstruct the star formation history and measure the dust production in the central regions of M33, and (2) using hot horizontal branch stars in omega Centauri to map extra-planar gas in its atomic and molecular tracers. |
| December 1st |
Prof. Nils Andersson
(Southampton) |
Pulsars as superfluid laboratories |
| Neutron stars are, at least in principle, laboratories for extreme physics. They are expected to contain superfluid components, the presence of which may affect their behaviour significantly. In this talk, I will discuss our current understanding of neutron star superfluidity in the context of observational evidence from pulsar glitches, free precession and magnetar oscillations |
8th
At 2.30pm |
Prof. Robert Nichol
(Portsmouth) |
Schuster Colloquium - Dark Energy: A lot of fuss about nothing |
| No abstract available! |
8th
At 4pm |
Sergio Colafrancesco
(INAF, Italy) |
Unveiling the nature of Dark Matter: radio astronomy challenges
& Beyond the standard lore of the SZ effect |
| Dark Matter is the dominant but yet unknown source of matter in the universe
and in cosmic structures at large scales. DM annihilation in cosmic structures (from galaxies to clusters of galaxies)
illuminates their DM halos and yields a multi-frequency spectral energy distribution
extending from radio to gamma-ray frequencies.
We discuss how the present and planned radio astronomy observatories
(from, e.g., VLA to SKA) can contribute and issue a challenge
in the search for the nature of Dark Matter.
The SZ effect is also an important astrophysical probe for the nature of DM since it provides inverse Compton scattering of CMB photons off the DM-produced secondary electrons.
More generally the SZE is a powerful astrophysical tool to study the energetics, spectra and stratification of the electron distribution in the atmospheres of cosmic structures.
To achieve this goal, we must go beyond the standard lore of the SZ effect.
Such a task is challenging for both the theoretical aspects of its modelling
and for the experimental goals to be achieved, but it will return a large
amount of physical information on different-scale cosmic structures
(galaxies, radio-galaxies, clusters of galaxies) by using the SZ effect as
a unique tool for astro-particle physics and cosmology. |
| 15th |
Jane Greaves
(St. Andrews) |
New debris disc insights from Herschel and prospects for ALMA |
| Debris discs are the dusty fallout of collisions between comets, and trace the otherwise invisible outskirts of planetary systems. Two far-infrared surveys are ongoing with Herschel - DEBRIS and DUNES - and results from the first few months of observing will be discussed. Systems around Sun-like stars are yielding particular surprises, being very different to our own Solar System. Some example science cases for high-resolution follow-up with ALMA will also be noted. |
15th
4pm |
Prof. Joao Alves
(Vienna,
Austria) |
It's not that massive stars are found in clusters, it's clusters that are found around massive stars |
| No abstract available! |
| January 26th |
Prof. Quentin Parker
(Macquarie, Sydney) |
Planetary Nebulae, past, present and future |
| I will briefly review the PN phenomena and describe the power of these
objects as probes of stellar evolution and Galactic evolution. I will
address their use as potent kinematic tracers and their value as
cosmological distance indicators. Finally I will review the recent
major progress in discovery, distance determinations and elimination
of mimics before touching on the future potential using
multi-wavelength optical-MIR-radio data. |
| February 2nd |
Anna Scaife
(Dublin Institute for Advanced Studies) |
The LOFAR Cosmic Magnetism Key Science Project - Recent results and future prospects |
| The low frequencies probed by the LOFAR telescope makes it a unique probe
of weak magnetic fields in the Universe. I will describe the LOFAR
Magnetism Key Science Project (MKSP) and give an overview of some of the
key science drivers which motivate this KSP. I will describe the
observational techniques being utilised to recover polarization and
magnetism information with LOFAR and show some of the early results from
the KSP commissioning. |
| 9th |
Pierre Maxted
(Keele) |
The WASP project - a wide-angle search for planets |
| The Wide Angle Search for Planets is a collaborative effort by several institutions to discover transiting exoplanets orbiting bright stars. The heart of the project are the two SuperWASP instruments which monitor millions of stars on a nightly basis. I will describe the instruments, the analysis of the data and the follow-up observations used to confirm the detection of new planets. I will also describe the properties of the many planets discovered by the project and some of the observations that have been used to characterize these extreme planetary systems. |
| 16th |
Mikhail Katsnelson
Radboud University, Nijmegen |
Schuster Colloquium - Graphene: CERN on the desk |
| The recent discovery of graphene has initiated huge activity in physics,
chemistry and materials science, for three main reasons. First, a peculiar
character of charge carriers in this material makes it a “CERN on the desk”
allowing us to simulate subtle and hardly achievable effects of high energy
physics. Second, it is the simplest possible membrane, an ideal testbed for
statistical physics in two dimensions. And last but not least, being the first
truly two-dimensional material (just one atom thick) it promises brilliant
perspectives for the next generation of electronics which uses mainly only
the surface of materials. I will concentrate on the first aspect: some unexpected
relations between materials science, quantum field theory and high-energy
physics. Electrons and holes in graphene have properties similar to those
of ultrarelativistic particles, leading to to some unusual and counterintuitive
phenomena, such as finite conductivity in the limit of zero charge carrier
concentration (quantum transport by evanescent waves) or transmission of
electrons through high and broad potential barriers with a high probability
(Klein tunneling). This allows us to study subtle effects of relativistic quantum
mechanics and quantum field theory in condensed-matter experiments, without
accelerators and colliders. Another interesting class of quantum-relativistic
phenomena is related to corrugations of graphene, which are unavoidable for
any two-dimensional systems at finite temperature. Gauge fields, one of the
central concepts of modern physics, are quite real in graphene and one can
manipulate them just by applying mechanical stress. |
| March 2nd |
Andrea Lommen
(Franklin & Marshall College, U.S.) |
The North American Nanohertz Observatory of Gravitational Waves (NANOGrav) |
| NANOGrav is a consortium of radio astronomers and gravitational wave physicists whose goal is to detect gravitational waves using an array of millisecond pulsars as clocks. Whereas interferometric gravitational wave experiments use lasers to create the long arms of the detector, NANOGrav uses earth-pulsar pairs. The limits that pulsar timing places on the energy density of gravitational waves in the universe are on the brink of limiting models of galaxy formation and have already placed limits on the tension of cosmic strings. Pulsar timing has traditionally focused on stochastic sources, but most recently I have been investigating the idea of detecting individual gravitational wave bursts wherein there are some interesting advantages. I will also demonstrate how the array can be used to reconstruct the waveform and obtain its direction. |
| 9th |
Peter Vukusic
(Exeter) |
Schuster Colloquium - All things bright and beautiful: The photonics of biological systems. |
| For the last decade, investigation of the photonics of brightly coloured animals
has become an exciting interdisciplinary area of research. The results suggest
broad innovation in nature’s use of photonics, with the flow of light and colour
being manipulated in many different ways. Many recent studies have revealed
system designs that have evolved and have existed naturally for millennia and
that were, until their discovery in nature, thought to have been the recent product
of technological innovation. This lecture will present an overview of this emerging
field of study, covering several of the exciting recent discoveries that reflect
nature’s optical design ingenuity and some technological applications
to which they are currently being applied. |
| 16th |
Graham Smith
(Birmingham) |
LoCuSS - A "Rosetta Stone" Survey of Galaxy Clusters at z=0.2 |
| The Local Cluster Substructure Survey (LoCuSS) is a study of a volume-
limited sample of 80 galaxy clusters at z=0.2 with the Subaru telescope,
and a wide range of space- and ground- based facilities. The main goals are
(i) to measure definitively the mass-observable scaling relations upon which
cluster-based attempts to measure the dark energy equation of state
parameter w will rely, and (ii) to measure the cluster-cluster scatter in
the star-formation rates and histories of galaxy clusters as part of a broad
community-wide effort to understand the physical origin of S0 galaxies. Our
results will also define a low-redshift benchmark that will aide the
interpretation of the growing menagerie of high-redshift cluster samples in
the coming decades. I will present an overview of the survey, and describe
our recent results, including those from our ongoing Herschel Key Programme
of far-infrared observations with PACS and SPIRE. |
| 23rd |
Martin Bureau
(Oxford) |
Molecular Gas and Star Formation in Local Early-Type Galaxies |
| The molecular gas content of local early-type galaxies is constrained
and discussed in relation to their evolution. First, as part of the
Atlas3D survey, we present the first complete, large (>250 objects),
volume-limited survey of CO in normal local early-type galaxies,
obtained with the IRAM 30m telescope. We find a surprisingly high
detection rate of 22%, independent of mass and environment but
dependent on the specific stellar angular momentum. Second, using CO
synthesis imaging with PdBI and CARMA, the extent of the molecular gas
is constrained and a variety of morphologies is revealed. The
kinematics of the molecular gas and stars are often misaligned,
implying an external gas origin in over a third of the systems,
although this behaviour is drastically diffferent between field and
cluster environments. Third, many objects appear to be in the process
of forming regular kpc-size decoupled disks, and a star formation
sequence can be sketched by piecing together multi-wavelength
information on the molecular gas, current star formation, and young
stars. This suggests an outside-in cessation of star
formation. Fourth, early-type galaxies do not seem to systematically
obey all our usual prejudices regarding star formation, following the
standard Schmidt-Kennicutt law but not the far infrared-radio
continuum correlation. This may suggest a greater diversity in star
formation processes than observed in disk galaxies and the possibility
of "morphological quenching". Lastly, evidence of a large-scale
AGN-driven molecular outflow in a local early-type galaxy is
presented, and a case is presented to establish the viability of
CO-based Tully-Fisher studies in early-types.
|
| 30th |
Giovanna Tinetti
(University College London) |
Schuster Colloquium - Exploring extrasolar worlds: from hot gas giants to terrestrial habitable planets |
| No abstract available! |
30th
4pm (TBC) |
Judith Croston
(University of Southampton) |
The environmental impact of radio-loud and radio-quiet AGN |
| Over the last decade it's become increasingly apparent, via the
combined results of X-ray observations, semi-analytic galaxy formation
models and cosmological simulations, that energy input from radio-loud
active galaxies plays an important role in the evolution of the
baryonic content of the Universe. However, the full picture of how
different AGN populations contribute at different epochs and in
different environments remains to be established. I will present
recent highlights of deep X-ray and radio studies that enable direct
measurements of the impact of AGN outflows ranging from powerful FRII
radio galaxies in cluster environments to weak kpc-scale jets in
nearby Seyfert galaxies, and will discuss the implications of these
results for the role of different AGN populations in galaxy evolution.
|
| April 6th |
Andrew Strong
(MPI Garching, Germany) |
The high-energy
interstellar medium of the Milky Way |
| Current observational data on the
high-energy components of the Galactic
interstellar medium provide a wealth of complementary information, which
can be exploited by building models which attempt to predict all the
observational material simultaneously. Cosmic rays, gamma rays,
synchrotron radiation and magnetic fields are among the essential
ingredients of such models. The aim is to obtain a self-consistent
picture. I will describe our modelling effort and what we are learning.
The talk will include latest results from the Fermi Gamma Ray Observatory.
The relevance to Planck will also be highlighted.
|
| May 4th |
Philipp Podsiadlowski
(Oxford) |
From Supernova to Hypernova: Understanding Supernova Diversity |
| It has becoming increasingly clear in recent years that there
is more to supernovae than just two explosion types. In this
talk I will first review the present classification scheme and
discuss the origin of some of the observed diversity. In
particular, I will demonstrate the importance of binarity for
understanding the diversity, using SN 1987A and SN 1993J as prime
examples. It is well established now that hypernovae, a more
energetic supernova type, are connected with long-duration
gamma-ray bursts. They only represent a small fraction of all
supernovae, but the evolution that leads to these dramatic and
rare events is not all understood. While it is known that most
neutron stars receive a large supernova kick when they are
born, there is also clear evidence that there is a subgroup of
neutron stars, apparently those born in close binaries, that
do not, suggesting a different explosion mechanism. Througout
the talk, I will emphasize the implications of the
uncertainties of our basic understanding of supernovae for
modelling the evolution of galaxies. |
| 13th**FRIDAY** |
Stephen Serjeant
(Open University) |
The Herschel ATLAS |
| No abstract available! |
| May 18th |
Prof. Glenn White
(Open University) |
Far infrared and submm surveys of the Galactic Plane - from AKARI to Herschel |
| Although most of our Galactic Disk is hidden behind thick layers of dust
and gas, observations with far-infrared space telescopes have revealed a
wealth of detail about the birth and formation of stars and their
interaction with the interstellar medium; the chemical composition of the
atmospheres and surfaces of comets, planets and satellites; the molecular
chemistry of the universe; and the properties of our Galactic Centre its
supermassive black hole. In this talk I will present some recent results
from the AKARI and HERSCHEL Galactic Plane surveys discussing: i) the
filamentary surprises in star formation regions; ii) the shocking effect
of triggering on the structure of high mass star formation regions, iii)
how life is lived on the fast lane around the Galactic Centre. |
| June 8th |
Simona Vegetti
(MIT) |
Detection of a Sagittarius-like satellite at cosmological distance. |
| The cold dark matter (CDM) paradigm predicts that a significant number of substructures, with a steeply rising mass function towards lower masses, populates the dark halo of galaxies. In the Milky Way, however, of order 104 substructures are predicted inside the virial radius, whereas only about 20 have been so far observed. This poses a major challenge to the CDM paradigm. New and independent methods are, therefore, required to assess the level of mass substructure in galaxies in the Local Universe and beyond. One such method will be discussed in this talk, which consists of three parts. First, I will present a newly developed fully Bayesian adaptive-grid method, that uses all the information contained in the surface brightness distribution of highly magnified Einstein rings and arcs, to detect and precisely quantify mass substructure in single lens galaxies, even in case of very high mass-to-light ratios. Second, I will present the recent detection of a Sagittarius-like satellite at redshift ~ 0.9. Third, I will discuss how to combine, in a statistical sense, the detections of mass substructures from multiple lens galaxies to constrain the substructure mass fraction fsub and the slope of the mass function α.
|
| June 15th |
Matthew Owens
(Reading) |
Solar cycle evolution of the heliospheric magnetic field |
| The distribution and evolution of magnetic flux at the photosphere is complex. It is dominated by mid-latitude magnetic flux emergence - sunspots - which subsequently migrate to the poles, ultimately facilitating the solar cycle polarity reversal. This is morphologically different to the field reversal observed in the heliosphere, which proceeds as a simple rotation of an approximately dipolar field. The magnetically-dominated corona links these two disparate regions, though the processes responsible for the necessary solar cycle restructuring of the corona are not well understood. It has been suggested that coronal mass ejections (CMEs) play a critical role in coronal reconfiguration, by shedding excess helicity, adding flux to the heliosphere and transporting open flux in the manner required for the solar cycle polarity reversal. I will attempt summarise these ideas and the observations which support them. |
