Supervisor: Dr. Ian Stevens

1) The Cygnus OB2 Radio Survey (COBRaS)*

Massive stars (such as O, B and Wolf-Rayet stars) are the energetic engines of galaxies, driving star-formation, outflows, energizing and enriching the interstellar medium. The large masses mean they have extreme luminosities and prodigiously strong stellar winds that shape and effect their environments. Massive stars also predominantly occur in binary systems with other massive stars leading to the phenomenon of colliding stellar winds, resulting in substantial X-ray emission and also non-thermal radio emission, which is not yet fully understood. This project focusses on the population of massive stars in the Cygnus OB2 star-forming region.

A large component of the project will involve working on the E-Merlin COBRaS survey of the Cygnus OB2 star-forming region, which is the central portion of the larger Cygnus X star-forming region.

Cyg OB2 is the nearest massive star-cluster and is likely to be a template for more distant star-clusters. E-Merlin - the heavily upgraded Merlin radio telescope network - will have greatly improved sensitivity at Gigahertz frequencies and allow us to survey the cluster in unprecedented detail. Associated multiwavelength studies, in the X-ray, optical and IR will add to our view of the cluster.

Specific tasks will include involvement in the E-Merlin data analysis as well as multiwavelength data (probably with a focus on X-ray data from the Chandra satellite as well as lower frequency GMRT data). The scientific focus will be on understanding emission from the numerous colliding wind systems that will be covered in the survey, to understand the nature and the origin of the non-thermal radio emission. Related to this we will also undertake theoretical calculations of the colliding wind phenomenon in support of the observations.

The COBRaS project involves about 30 scientists in the UK, USA, Canada, Belgium, Italy, India and Ireland and this project will involve participation in team meetings as well as likely observing trips to obtain additional data.

For more information please contact Dr. Ian Stevens (Email: irs[at]star.sr.bham.ac.uk)

2) Massive Stars, Star-formation and Star-Clusters in Nearby Galaxies

This Ph.D project will involve working on the upcoming LeMMINGS (Legacy E-Merlin Multi-band Imaging of a complete Nearby Galaxy Sample) survey.

E-Merlin represents a major upgrade to the Merlin radio telescope network, and will provide extremely high resolution and very deep images of the radio sky. The LeMMINGS survey aims to provide the "definitive microJansky sensitivity radio images of a large sample of nearby galaxies". It will do this by observing around 40 nearby (within 20 Mpc) galaxies in a deep survey (and rather more in a shallower survey). These galaxies will consist of all types, from small dwarf galaxies, to larger elliptical and spiral galaxies.

The overall goals of this project are to understand the processes of star-formation and accretion (such as from black-holes) in nearby galaxies. Radio observations suffer much less from obscuration, which is a major issue at optical wavelengths and hence can provide a much more complete census of the contents of galaxies.

This particular Ph.D project will likely focus on two main areas with LeMMINGS, namely radio emission from young massive star-clusters and star-formation regions (including emission from the extreme super stars clusters) and also radio emission from ultraluminous X-ray sources (ULXs). The nature of these objects is still unclear, but they are mostly related to regions of star-formation and massive stars - they could be a new class of intermediate mass black-hole (objects with a mass intermediate between that of stellar mass black-holes such as Cyg X-1 and the massive black-holes in the centres of galaxies) or extreme X-ray binaries where the emission is highly beamed. The higher resolution and sensitivity of E-Merlin will help to answer questions about their nature.

The student will be involved in basic data analysis of the E-Merlin data as well as detailed studies of individual objects or classes of objects. The student could also be involved with some early science verification and/or commissioning observations with e-MERLIN.

The LeMMINGS teams consists of around 40 scientists from the UK, USA, Germany, France, Holland, Spain, Sweden, Chile, India and Australia. This project will involve participation in team meetings as well as likely observing trips to obtain additional data on the sample.

For more information please contact Dr. Ian Stevens (Email: irs[at]star.sr.bham.ac.uk)

Supervisor: Dr. Ian Stevens

The search for and the study of extrasolar planets will be one of the major challenges facing astrophysics over the next few years, and one which will have a profound impact on our understanding of our place in the Universe. Many important questions, like how common are planets, how common are "habitable" planets (and indeed what does "habitable" mean) and so on, remain to be answered.

There are projects in a number of areas available at the University of Birmingham.

1) Transiting extrasolar planets and stellar variability

We are currently using the HI instruments on the two STEREO satellites to investigate a wide range of stellar variability and to hunt for extrasolar planets via transits. Although these instruments were primarily designed to look for "Space Weather" events, such as coronal mass ejections, they provide CCD images of large portions of the sky, enabling the photometric monitoring of many stars.

As part of this project we will obtain long-term light curves of lots of stars, which will yield important new information. In addition to extrasolar planets we are investigating stellar pulsations (both solar-like oscillations, Cepheid variability and semi-regular variables) and a range of eclipsing binaries.

Work in this area will involve ongoing development of the data pipeline and also analysis of the stellar lightcurves. Development of algorithms to classify these lightcurves in an automatic manner is also a possibility.

This work is being done in conjunction with Bill Chaplin and Yvonne Elsworth from the BISON group.

2) Magnetospheric radio emission from extrasolar planets, brown dwarfs and related objects

Extrasolar planets are expected to emit low frequency radio waves, in the same way that Jupiter (or its magnetosphere) is a bright low frequency source. Because extrasolar planets are more distant, they are difficult to detect. We have already investigated the scaling of radio emission, depending on the distance of the planet from the star, mass of the planet etc, and made predictions about the levels of expected radio emission. One prediction is that exoplanets should be detectable using the upcoming Low-Frequency Array (LOFAR), a low-frequency radio telescope array, operating in the frequency range of 30-200MHz currently being constructed in Holland. The detection of emission from extrasolar planets will allow us to investigate extrasolar planets in novel ways, such as determining the magnetic field strength of the planets (important in understanding their internal structure), rotation rate, presence of moons and so on.

This project will involve both theoretical studies of the expected emission from extrasolar planets, using improved descriptions of the planetary and stellar properties and observations of the low frequency emission.

The emission mechanism for low frequency radio waves from extrasolar planets is the electron-cyclotron maser (ECM), a process involving the emission from electrons in the radiation belts of the planets. Planets are not the only source of ECM radiation, and it is believed that brown dwarfs (or at least some brown dwarfs) also show ECM emission. Other sorts of magnetic stars also probably show such radio emission, though how common it is remains uncertain.

We have a developing program to observe and study the radio emission from brown dwarfs and related objects (such as CU Virginis). This project will involve undertaking observing trips to the GMRT telescope in India as well as data from the E-Merlin array and also the eVLA.

For more information please contact Dr. Ian Stevens (Email: irs[at]star.sr.bham.ac.uk)