Some
Beam Formed modes (BF), and even a combination of them, can be run in parallel with the standard
imaging mode (IM). This allows one to simultaneously image a field while recording high time resolution dynamic spectra to probe sub-second variations of any source in the field.
The BF+IM commensal observation configuration boundaries are:
- BF and IM share the exact same station settings (field set, clock, bitmode, antenna set, SAP pointings, etc); The beamforming can use a sub-set of stations used for the imaging observations. In particular for the Coherent Stokes, it is therefore important to use only core stations for combined observation.
- BF and IM have independent processing settings (frequency & temporal resolution, etc).
- At the start of the cycle, BF processing may not yet be available for this mode and the raw data will be ingested instead.
We offer three modes:
1) Imaging with Remote + Core stations and Coherent Stokes beamforming with Core stations only
- HBA_DUAL, HBA_DUAL_INNER
- One direction / sub-array pointing
- Two Tied-array beams Stokes I, Stokes IQUV or Complex Voltage
- Up to 244 subbands
- Standalone, calibrator-target-calibrator, target-calibrator strategy
2) Imaging with Remote + Core stations and Incoherent Stokes beamforming with Core stations only
- HBA_DUAL, HBA_DUAL_INNER
- One direction / sub-array pointing
- One incoherent array beams, Stokes I or Stokes IQUV
- Up to 244 subbands
- Standalone, parallel calibrator, or calibrator-target-calibrator strategy
3) Fast Imaging + multi-beam observation with
- Imaging with Remote (up to 10) + Core stations,
- Beamformed multi-beam with 6 rings with the Core only
- Antenna set: LBA_OUTER
- Beamformed resolution 12.2 kHz, 0.01 seconds
- Imaging resolution 12.2 kHz, 0.25 seconds
- Up to 60 subbands
- This can be accompanied by:
-
- Three parallel observations with a single station (2x Stokes IQUV, 0.01s, 12.2 kHz 400 SB and 1x CV, 400 SB) and a parallel fly’s eye observation with up to 14 international stations (12.2 kHz, 0.01s, 400 SB) using any of LBA_OUTER, LBA_SPARSE_EVEN, HBA_DUAL, HBA_DUAL_INNER
A full characterization of BF + IM observations needs to be performed in light of the COBALT2 upgrade and the LOFAR MEGA MODE implementation. This will make a wider set of observations available in future cycles.