Answering the Big Science Questions
A number of key 'big science questions' have been posed in the STFC Particle Physics and Astronomy roadmap. e-MERLIN will be the instrument of choice for many astronomers to address some of these questions - a process that has already started through the approved e-MERLIN Legacy projects
What is the Universe made of and how does it evolve?
Gravitational lensing provides our most powerful diagnostic of the distribution of dark matter on galaxy and cluster scales. Gravitational lenses were first discovered at radio wavelengths using a forerunner of MERLIN at Jodrell Bank and MERLIN played a key role in finding the majority of gravitational lenses in the 1990s using a series of VLA and MERLIN surveys. CDM simulations predict that galaxies and clusters should have lumpy substructure. Detailed studies of individual gravitational lenses using high resolution studies (<0.1 arcsec) will provide important constraints on the degree and distribution of this substructure. Optical observations suffer from extinction which makes the observed flux ratios harder to use.Associated Legacy projects: Gravitational Lensing
Are we alone in the Universe?
As the material in proto-planetary disks aggregates from dust to pebbles and hence planetesimals, the spectral energy distribution changes. In order to interpret this properly, and remove the contribution from free-free emission due to ionised gas, observations at cm and sub-mm wavelengths are required. e-MERLIN will have the required sensitivity and angular resolution to do this, at least in the closest star-forming regions. National Facility staff developed equipment for and observed with the Lovell Telescope as part of Project Phoenix, the most sensitive search yet carried out for signs extraterrestrial intelligence.Associated Legacy projects: PEBBLES
How do galaxies, stars and planets form and evolve?
This is the primary science theme for e-MERLIN. High resolution radio observations are crucial for obtaining an extinction-free view of the evolution of stars and galaxies, measuring star formation in distant galaxies, assessing the incidence and role of black holes and AGN in the evolution of galaxies and feedback processes controlling starformation rates, and probing distant clusters using AGN as tracers. In our own Galaxy e-MERLIN will be able to study the jets and winds which are such a crucial part of the star formation process, constrain the kinematics and magnetic field distributions in star forming regions using OH and methanol maser lines, and make detailed images of later phases of stellar evolution such as planetary nebulae and circumstellar material in AGB stars. In nearby galaxies e-MERLIN will resolve many hundreds of SNR and HII regions including super star clusters.Associated Legacy projects: e-MERGE AGATE COBRaS LIRGI LeMMINGS Massive Star Formation Thermal Jets
What are the laws of physics in extreme conditions?
High resolution radio observations have been a primary source of information for studying energetic processes around black holes, whether in our own galaxy, nearby radio galaxies or distant quasars. MERLIN has produced detailed images of the jets produced by all these objects. e-MERLIN will extend this science using detailed spectral and polarimetric studies of jets to obtain their internal and magnetic structures.Within the Milky Way, the astrometric study of radio pulsars allows a detailed investigation into the physics of neutron star formation during supernovae and hence improves our understanding of Galactic structure. Observations with e-MERLIN will more than double the number of pulsars with measured accurate distances and velocities. Model independent velocities will place strong constraints on the mechanism responsible for the 'kick' that is often impaired during the supernova in which the neutron star is formed and that makes the velocity of neutron stars the highest of any class of star. Such constraints are essential for probing the laws of physics at the extreme conditions that occur during supernova core collapse. Associated Legacy projects: Extragalactic Jets e-PI
How does the Sun affect the Earth?
MERLIN is regularly used in conjunction with EISCAT for studies of the structure of the solar wind, and to observe interplanetary coronal mass ejections. e-MERLIN will allow these studies to be extended, by enabling fainter objects to be used as probe sources. e-MERLIN will operate in conjunction with lower frequency observations using LOFAR.