The two invited talks will be 30 minutes long, with 10 minutes for discussion. Contributed talks will be 15 minutes long with 5 minutes for discussion. We will update this page once the programme of contributed talks has been finalised.
YAM Talks
10:00 Registration and coffee
10:30 Introductory Remarks
10:40 Sarah Bridle (University College London)
Using new technology to make your research easier
11:20 Discussion break
11:30 Gareth Williams (Queen Mary, University of London)
Embedded Satellites in Saturn's F-Ring
Images from the Cassini spacecraft have shown that Saturn's F-ring has intriguing structures that can appear and disappear on short timescales. Some of these features can be explained by the perturbations from the two satellites, Prometheus and Pandora, on the ring. Other features can only be explained by small satellites that are embedded or passing through the ring on a regular basis.
Numerical and analytical approaches have been used to study a planet-satellite-ring system. A co-orbital map has been created to model the three important regions of ring-satellite encounters: the horseshoe, chaotic and passing zones.
The results show the connection between features in a ring with the physical and orbital parameters of a perturbing satellite. They also provide good agreement with some of the observed structures thereby placing limits on the population of embedded satellites within the F-ring.11:50 James Furness (University of Sheffield)
Observations of Massive Star Formation
I present an overview of massive star formation through far-infrared observations from Spitzer/MIPS, plus mid-infared observations from VLT/VISIR and Gemini/MICHELLE. When massive stars are born, they are enshrouded in their dusty natal cocoon, rendering them optically invisible. This makes direct studies impossible until the star is well past its zero age main sequence. However, before this time we wish to understand the formation of the stars, the multiplicity (born in clusters or isolation) and stellar properties. The methods utilised in trying to answer these questions are shown along with my results.12:10 Discussion break
12:30 David Boyce (University of Leicester)
Death of the Local Hot Bubble
White dwarf stars have long been used as the background source by which to probe the local interstellar medium (LISM). The discovery of heavy metal absorption lines in the atmospheres of the white dwarfs has made the process of distinguishing between the star lines and the LISM lines difficult. Studies of the LISM have have become limited by how well we can model the stellar spectrum and have thus ground to a halt. We present a new method in absorption spectroscopy that takes advantage of how similar white dwarfs can be to each other to classify unknown LISM absorption lines. This method is successful at identifying a factor of 10 increase in the detected number of LISM lines and enables us to report the discovery of a large crop of previously undetected elements in the ISM. This new information changes our view of the behavior of the LISM in the gas phase and allows us to study, in more detail than ever before, its depletion into dust grains and hence place tighter constraints on the input parameters for star formation models. the method also exposes how many previously identified lines are misidentified. The method looks at the velocity of the lines and compares this with the photospheric velocity of the star. This velocity analysis is powerful in that it can indicate where a given line has originated. Our method shows that in all cases within the local bubble the O VI lines, previously declared as LISM, is stellar in origin. This finding changes our view of the hot local bubble by critically undermining the only remaining evidence for its hotness. All indications from our studies indicate the temperature of the milky way in our neighborhood is significantly cooler than previously thought.12:50 Scott Gregory (University of St Andrew's)
The magnetic fields of young suns
Young solar analogs, called T Tauri stars, are actively accreting material from large dusty proto-planetary discs. Gas is channelled along the field lines of the stellar magnetosphere and rains down onto the surface of the star producing detectable hotspots. Polarisation measurements made using photospheric absorption and accretion related emission lines, have provided indirect clues about the complex nature of T Tauri magnetic fields. Until very recently, however, little was known about their true magnetic field topology, with the majority of accretion models assuming simple dipolar fields. Using a technique called Zeeman-Doppler imaging we have, for the first time, mapped the distribution of magnetic polarities across the surface of forming solar-like stars. By extrapolating from such surface magnetograms we have reconstructed the 3D magnetic field geometry. We have modelled how the process of accretion distorts the immediate circumstellar environment, and how large columns of accreting material can influence the stellar coronal X-ray emission. Ultimately this work will shed new light on the history of our own Sun and Solar System at a time when the planets were just beginning to form.13:10 Poster slide presentation
13:30 Lunch and poster viewing
15:00 Iraklis Konstantopoulos (University College London)
The Universality of Star Cluster Formation Modes
The study of stellar cluster formation and evolution is essential to astronomy. Recent research has shown that virtually all star formation occurs in a clustered fashion (Lada & Lada (2003) ARA&A 41 57). In extra-galactic environments, clusters are found to be brighter and more massive than in the Milky Way, which appears to represent one of many different star formation modes available in the Universe.
These Young Massive Clusters (YMCs) appear in all sorts of astronomical environments. Two comprehensive studies of the collective morphology (i.e. size and shape) of cluster populations discover similar sizes and shapes for clusters in regular spiral galaxies (Larsen (2004) A&A 416 537) and the Magellanic Clouds (Mackey & Gilmore (2003) MNRAS 338 85). Those environments are very different in terms of scale and the properties of the interstellar medium, which, in this narrow sample of cluster native environments, seems to argue for a Universal star cluster formation mode.
In order to investigate this effect further, we have measured sizes for some ~1000 YMCs in archetypal starburst galaxy M82. This galaxy is closer than most studied extra-galactic environments, which presents an advantage in that cluster light envelopes are well-resolved and therefore size can be measured more accurately. Theoretical studies expect a relationship between external pressure and cluster size (Elmegreen (2007) ApJ, in press). We examine M82 cluster sizes with the aim of uncovering any environmental dependencies. I will be presenting results and discussing the implications to our current framework of star formation.15:20 Bruno Henriques (University of Sussex)
Disruption of Dwarf Galaxies in Semi-Analytic Models
I will present results for a galaxy formation model that includes disruption of dwarf galaxies by gravitational forces and galaxy encounters within galaxy clusters. This is implemented "a posteriori" in a semi-analytic model by considering the stability of cluster dark matter sub-haloes at z=0.
We assume that a galaxy whose dark matter substructure has been disrupted will itself disperse, while its stars become part of the population of intracluster stars responsible for the observed intracluster light. Despite the simplicity of this assumption, our results show a substantial improvement over previous models. This indicates that the inclusion of galaxy disruption is indeed a necessary ingredient of galaxy formation models, bringing the luminosity functions and the color-magnitude relations into a much better agreement with observations.15:40 Leila Powell (University of Oxford)
Hot Gas and Dark Matter Substructure in Cosmological Simulations of Galaxy Clusters
Various differences in galaxy cluster properties derived from X-ray and weak lensing observations have been highlighted in the literature. One such difference is the discovery of mass concentrations in lensing maps which have no X-ray counterparts. We investigate this issue by analysing and comparing substructures detected in maps of projected X-ray surface brightness and projected total mass for three simulated clusters. This allows us to investigate whether the distributions of the dark matter and hot gas components do indeed differ and , if so, how these differences depend on various cluster (and simulation) properties. Analysing 3D subhalo data for the clusters also enables us to associate subhalo masses with the 2D mass map substructures and to assess the impact of projecting the data on substructure identification.16:00 Discussion break
16:20 Stuart Lynn (University of Edinburgh)
Halo Modeling of the large scale structure for future galaxy surveys
The next 10-20 years see a number of new surveys (PAN-STARRS and LSST to name but a few) which will have a large impact on our understanding of cosmology. These surveys aim to map nearly the entire sky giving us, through lensing and galaxy surveys, an unprecedented insight in the large scale structure of the universe and indirectly the value and possible evolution of the dark energy equation of state.
To gain the full potential from these surveys realistic mock galaxy catalogues need to be created. These mocks can be used in several different ways: to plan survey strategies, test techniques such as how to measure lensing statistics and also to compare the ultimate results of these surveys with theory.
The current method of producing these mocks involves computer intensive semi-analytic modeling methods and high resolution dark matter simulations. I present a method based on the halo model which can be run on a desktop machine in less than a day and discuss how it might be used.16:40 Stephen Wilkins (University of Cambridge)
Tension in the Star Formation History: evidence for a possible evolution of the IMF?
The star formation history of the universe is a crucial description of the evolution and formation of galaxies. However, measurements of this function using different methods yield significantly different results. This can be explained in a number of ways including systematic errors in the measurements, incorrect dust assumptions or the speculative possibility of an evolving initial mass function.17:00 Chris Lintott (University of Oxford)
Galaxy Zoo: What to do with 105 research assistants
The Galaxy Zoo project invited members of the public to classify galaxies imaged by the Sloan digitial sky survey by eye. This is a robust method of dividing spiral galaxies from early types; other methods such a cutting by colour risk losing the most interesting part of the sample. After three months, more than 110,000 people had provided more than 32 million classifications. We present the initial highlights of this effort, including the early-type galaxies with the highest star formation rates yet seen, possible large-scale anisotropies in the distribution of spiral galaxies and a catalogue of new strong gravitational lens candidates. There are also opportunities for people to get involved in Zoo2, the next stage of the project.17:20 Discussion break
17:30 Pedro Russo (IAU & ESA/Hubble)
Communicating Astronomy
Science Communication plays a crucial role in education and in the public understanding of science. It shortens the distance between scientific research, the school and the general public. Astronomy has a privileged position in the process of science communication since it embraces different areas of knowledge such as mathematics, physics, chemistry, geology and biology. It is capable of attracting a vast audience and is a powerful tool for science popularization.
Nowadays, science must compete with many other subjects for a place in the media and in the public's attention. This paradigm has raised the standards and demands for science communication and pushed it into professionalism. The International Year of Astronomy 2009 (IYA2009) is one of the biggest challenges for astronomy communication.
There are two key elements in the communication strategy that are often forgotten: detailed description of objectives and goals and evaluation of the results. They are in opposite poles of the communication strategy, but must both be taken into account from the beginning of any activity. In this talk I will present some guidelines that can be helpful in the initial planning of outreach activities, as well as the evaluation of its results.
The Local Organising Committee are keen to hear any questions or comments you might have ahead of the meeting and can be contacted at ras-yam@roe.ac.uk.