e-MERLIN is an array of seven radio telescopes spanning 217 km across the UK connected by a superfast optical fibre network to its headquarters at Jodrell Bank Observatory. It has a unique position in the world with an angular resolution comparable to that of the Hubble Space Telescope and carrying out centimetre wavelength radio astronomy with micro-Jansky sensitivities.
Its flexible wide-band correlator enables e-MERLIN to become the core of the EVN (European Very Long Baseline Interferometer Network) providing those valuable shortest baselines to global VLBI scientists. The array is also flexible enough to be used for sensitive pulsar observations in very-high time-resolution modes.

Three Observing Modes with Three Observing Bands
(L, C & K)

e-MERLIN regularly operates its wide-band correlator in three modes:
Direct Correlation Mode, VLBI VDIF Mode, and Pulsar VDIF Mode.
Three observing bands are available:
L band (1.25 - 1.75 GHz), C band (4.5 - 7.5 GHz), and K band (20 - 24 GHz).

Direct Correlation Mode

This is the most frequently used mode by observers providing deep high-resolution imaging. e-MERLIN observations are correlated at Jodrell Bank, in real time, using aperture synthesis techniques. Telescopes spread over 217 km, combined with 512 MHz instantaneous bandwidth, yield overlapping spatial-scale coverage in a single earth-rotation.

This coverage delivers images with angular resolutions up to 50 milli-arcseconds at micro-Jansky sensitivities. On top of these continuum observations, the e-MERLIN correlator can simultaneously observe narrow spectral windows with very-high frequency resolution, ideal for spectral line observations.

VLBI VDIF Mode

When used within the European VLBI Network, e-MERLIN generates EVN compatible VDIF data which are delivered to JIVE for correlation. Images produced with e-MERLIN + EVN deliver micro-arcsecond angular resolution without sacrificing the larger scales. Both traditional VLBI (observe now, correlate later) and fibre-linked 'e-VLBI' (real-time correlation) modes are available.

Pulsar VDIF Mode

e-MERLIN VDIF mode data can also be combined to produce exceptional sensitivity and time resolution combinations. This is ideal for low luminosity pulsar observing, FRB searches or even the Search for Extra Terrestrial Intelligence (SETI).

Observe with e-MERLIN

e-MERLIN announces regular observing cycles (currently twice per year), inviting the astronomical community to propose new experiments. Typical observations, using the Direct Correlation Mode, yield micro-Jansky sensitivities in a single observing track with excellent aperture synthesis coverage thanks to 512 MHz of bandwidth and up to 50 milli-arcseconds of angular resolution at C-band. Full support is available throughout the proposing, observing and data reduction processes from specialist Support Scientists. The bespoke CASA data reduction pipeline tool can automatically process data faster than real-time allowing rapid results.

For more information on e-MERLIN's capabilities and on how to observe please see our 'Observe' section.