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e-MERLIN : a pathfinder for the SKAe-MERLIN : a pathfinder for the SKA(a summary of the e-MERLIN talk given at the Berkeley SKA meeting)(a summary of the e-MERLIN talk given at the Berkeley SKA meeting)
e-MERLIN : a pathfinder for the SKAe-MERLIN : a pathfinder for the SKA(a summary of the e-MERLIN talk given at the Berkeley SKA meeting)(a summary of the e-MERLIN talk given at the Berkeley SKA meeting)
P.J.DiamondP.J.DiamondP.J.DiamondP.J.Diamond
MERLIN/VLBI National FacilityMERLIN/VLBI National Facility
Jodrell Bank ObservatoryJodrell Bank Observatory
University of ManchesterUniversity of Manchester
MERLIN/VLBI National FacilityMERLIN/VLBI National Facility
Jodrell Bank ObservatoryJodrell Bank Observatory
University of ManchesterUniversity of Manchester
11/7/01 11/7/01
e-MERLIN www.merlin.ac.uk/e-merlin
• Fibre connection to telescopes; new correlator
• 2 GHz/pol instantaneous bandwidth
• Data rate increases from 128Mb/s/tel to 40Gb/s/tel
• Sensitivity ~ 1 Jy/b in 12hr (> 30 over current system)
• Correlator operates in permanent wide-field mode– e-MERLIN will provide FOV ~ 0.5 degree at 1.4 GHz,
~10 arcmin at 5 GHz. Images will have as many pixels as VISTA – 400,000,000 per channel
– Output data rate 0.5 TB/day
– Hundreds of sources in each observation – superb high-res archive for data mining (AstroGrid, e-science)
• Complete aperture coverage via MFS
e-MERLIN capabilities
Band Frequency
(GHz)
Current Sensitivity
(Jy)
e-MERLIN sensitivity
(Jy)
Brightness
(K)
Resolution
(arcsec)
UHF 0.327/0.408 700 200 7020 0.5
L 1.0 – 2.0 35 4 140 0.14
C 4.0 – 8.0 50 1.4 47 0.04
X 8.0 – 12.0 N/a 1.4 47 0.02
U 12.0 – 18.0 N/a 3.0 104 0.013
K 18.0 – 26.0 400 11.3 390 0.008
Key programme sensitivity: 200 hours at 5 GHz 350 nJy rms
e-MERLIN Science
• Cosmology – gravitational lenses, JVAS/CLASS,
constraints on cosmological parameters, e.g m and
Gravitational Lenses from JVAS/CLASSCurrent constraints: Red from supernovae e-MERLIN constraints
Green from Boomerang, JVAS/CLASS as contours
• Galaxy Formation & Evolution: nature of submm galaxies, starbursts, X-ray background.• 100’s of sources in primary beam.
e-MERLIN Science
HDF: contours are MERLIN+VLA 1.4 GHz emission, rms = 3.5Jy/beam
Statistical detection of < 10Jysources in HDF. Excess radio emission clearly seen for I <26,implying majority of galaxies at this level detectable by e-MERLIN
• Star-formation:– Imaging thermal jets and outflows in YSOs– Maser emission in star-formation regions
Studies of magnetic fields:masers, circular polzn fromplasmas, linear polzn of synchrotronsources
MERLIN 6cmMeaburn et al
Ori A
Non-thermal radio source
Trapezium Cluster
e-MERLIN Science
1400 AU
Subaru
HST300 AU
MERLIN
Seeing through the dust: 150 magnitudes
of optical extinction
Gemini
BD +30o 3639
Planetary Nebulae
MERLIN Chandra
• Main sequence and evolved stars – novae, stellar coronae,
planetary nebula, surfaces of supergiants/giants
e-MERLIN Science
Nova V723 Cas
MERLIN 6cmVLA 7mm
Imaging stellar surfaces
• Extreme environment astrophysics – micro-quasars, relativistic jets in AGN, pulsar proper motions, GRBs ……
e-MERLIN will provide detailed images
of Cygnus A-like objects at 10 times the
distance currently possible.
e-MERLIN Science
e-MERLIN: straw-man timetable (now out of date)
Fibres Installed
LT upgraded
5 year timeline
Cost of leasing dark fibre
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
1996 1997 1998.5 1999.5 2000.5 2001.5
Euro/Mbps/yr
0
1
2
3
4
5
6
1996 1997 1998.5 1999.5 2000.5 2001.5
Euro/Mbps/yr
e-MERLIN status
• Re-scoped project: – deferred 12-18 GHz system
– adopted ALMA data transmission system => 1.5 GHz bandwidth (i.e. 12.5% hit in sensitivity)
– Cost now £7.0M
• March, 2001 --- highly rated by Astronomy Committee
But no capital cost available from PPARC.
• May 2001, final resolution of capital cost:– NWDA: £2.5M
– SRIF: UMan £2.0M, UMIST £0.25M, UCam £0.25M
– Savings on MERLIN Ops: £1.3M
– U Manchester willing to underwrite remainder: £0.7M
£7.0M
e-MERLIN status• Current status:
– Negotiations underway with PPARC on future operating costs
– September, cost and risk assessment
– Early 2002 start project build phase.
From e-MERLIN to SKA• Develop digital, fibre etc technologies essential for SKA
• Learn how to operate fibre-based system with SKA-like baselines
and in hostile RFI environment
• Maintain British astronomical expertise in cm-wave interferometry
• e-MERLIN will have Jy sensitivity at < 0.1 arcsec resolution
demonstration of range of science possible with SKA