Table 1
Technical capabilities of e-MERLIN once the upgrade is complete. The Lovell telescope may be included in the array at 1.5 and 5 GHz; this increases the sensitivity by a factor of between 2 and 3, but reduces the field of view. For current capabilities, see http://www.e-merlin.ac.uk/
| 1.5 GHz (L-band) | 5 GHz (C-band) | 22 GHz8 (K-band) | |
|---|---|---|---|
| Resolution1 (mas) | 150 | 40 | 12 |
| Field of view2 (arcmin) | 30 | 7 | 2 |
| Frequency range (GHz) | 1.3 – 1.7 | 4 – 8 | 22 – 24 |
| Bandwidth3 (GHz) | 0.4 | 2 | 2 |
| Sensitivity4 (µJy/bm) | 5 – 6 | 1.8 – 2.3 | ~15 |
| Surface brightness sensitivity4 (K) | ~190 | ~70 | ~530 |
| Astrometric performance5 (mas) (ICRF) | ~2 | ~1 | ~2 |
| Astrometric performance6 (mas) (day-to-day) | ~0.5 | ~0.2 | ~1 |
| Amplitude calibration7 (%) | 2 | 1 | 10 |
[i] Notes 1: with uniform weighting, at the central frequency. 2: FWHM of 25-m dishes; reduced when the Lovell telescope is included. 3: Maximum bandwidth per polarization. 4: In a full imaging run with the Lovell telescope. 5: With respect to the ICRF (typical 3-deg target-calibrator separation using the VLBA Calibrator Survey). 6: Day-to-day repeatability using surveyed or in-beam sources, and assuming full imaging run. 7: Targets for day-to-day repeatability. 8: The Lovell telescope is not available at 22 GHz.
Table 2
Input parameters required for the operation of the e-MERLIN pipeine. All of the listed tasks are performed if set equal to 1, and not performed if set to -1. If not present in the inputs file, they all default to -1 in order to avoid damaging data already present in the user’s AIPS catalogue. Tasks denoted with * are those which require additional parameters (documented in the example “doall.inputs” which is distributed with the pipeline).
| userno = 19 | AIPS number to use (no default) |
| indisk = 1 | AIPS disk to use |
| targets = B1938+666 | List of target sources |
| phsrefs = J1939+123 | List of phase calibrators |
| fluxcals = 1331+305 | List of flux calibrators |
| bpasscals = 1407+284 | List of bandpass calibrators |
| pointcals = 1407+284 | Source to use as point calibrator |
| widetargets = B1938+666 | List of targets for wide-field imaging |
| fitsdir = /local/scratch/user/ | Location of data to load |
| plotdir = /local/scratch/user/ | Where to write plots, defaults to current working directory |
| fittpdir = /local/scratch/user/ | Where to backup fits, default as above |
| doload * | Load data (from list in fitsdir) |
| doflagmask | Apply the e-MERLIN flagmask |
| doavg * | Average data in time and/or frequency |
| dodiagnostic1 | Make diagnostic plots |
| doflag * | Apply SERPent autoflagger |
| dodiagnostic2 | Post-flagging diagnostic plots |
| doback | Backup the flag tables |
| doconcat | Concatenate data into one database for calibration |
| docalib * | Perform some or all of the calibration procedures |
| doimage | Image the phsrefs and targets |
| dowide * | Image the full primary beam for the sources in widetargets |
Figure 1
Left: archival C-band image of the gravitational lens system B1938+666 from MERLIN data. Right: pipelined image of the same source, made using the C-band verification dataset and v0.7 of the pipeline with no human intervention.