Cycle-3 Capabilities and the OT

Andy Biggs

ALMA Regional Centre, ESO

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

New ALMA capabilities for Cycle 3

• Band 10• Baselines up to 10 km• FDM full polarization• Total Power in Bands 9 and 10 (probably)• 40 12-m array antennas (probably)• DiffGainCal

– Band-2-Band transfer– Bandwidth switching

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Band 10

• Frequency coverage: 787-950 GHz (381-316 μm)• Angular resolution: ≈ 520-40 mas• OT will assume 40 12-m array antennas

– Actual number may be smaller

• Receiver temperature– Specification was 230 K (DSB) over 80% of band– OT will probably use a better figure

• 1st octile of PWV across whole band– 0.452 mm

• No mosaics (hot off the press!)

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Band-10 Transmission

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Long baselines

• Defined broadly as > 1.5 km• Baselines up to 10 km will be available• Available configurations will be band-dependent

– B3, 4 and 6: ≤ 10 km– B7: ≤ 5 km– B8, 9 and 10: ≤ 1.5 km

• Reminder: ALMA will extend out to 16 km, eventually• Phase calibrator cycle times will depend on

– Band– Frequency

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Array selection

• This will be similar to Cycle 2• OT will automatically choose arrays based on

– Angular resolution– Largest Angular Scale

• Up to two 12-m configurations are allowed• “Long baselines” are fairly restricted

– Only have one 12-m configuration– No ACA

• No TP if MRS(12m) < LAS < MRS(7m)– This is new

• ACA times will remain a multiple of the 12-m time

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Full polarization

• Cycle 2– Only TDM default frequencies were allowed– Bands 3, 6 and 7

• Cycle 3– TDM and FDM at arbitrary frequencies– All FDM bandwidths will be available (1875-62.5 MHz)– Still only Bands 3, 6 and 7

• Still on-axis only (single pointings)• Only linear polarization officially supported• Only one tuning per SG• 3-hour minimum time estimate will remain

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Total Power at Bands 9 and 10

• Single dish sideband separation now possible– Data reduction and analysis has been demonstrated

• “Spectral line” only– No nutator or “fast scanning” mode for continuum

• May be dropped– Band-8 TP may also be dropped (flux calibration issues)

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Sesame name resolver

• The OT has a “resolve” function for field sources– Positions/velocities automatically entered based on source

name

• Previous interface had some problems– Queried multiple servers– ESO shut the NED server we were using– How it worked was quite opaque (and dangerous)

• Now using Sesame (by Simbad)– Searches Simbad and NED– One interface so easier to maintain– Must enter a recognised source name

• Science Archive already uses this

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Antenna beamsize

• OT has always assumed 1.2 λ / D• This will change to 1.13 λ / D

– TP SB generation had already been changed

• More mosaic pointings will result

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Correlator modes

• No change...• Except for full polarization equivalents of existing FDM• Reminder of existing capabilities

– 4 independent basebands (TDM or FDM)– 4 spws per baseband (all must have same spectral resolution)

• For the future...– Multi-resolution modes– Over-sampling (twice Nyquist)– Different quantizations (3 and 4-bit)– 32.5 MHz-wide spws

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Spectral Scan overlaps

• Cycle-2 OT assumed zero overlap for max. coverage• Quality of edge channels can be poor

– Ringing

– Bad Tsys measurements

– This is in addition to the TDM channels that are usually flagged

• An overlap will therefore be enforced in Cycle 3– Only a few TDM channels– Bandwidth dependent

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Time estimates

• All tunings will stay in one SB– Will be observed in separate SBs though– Time estimates will be corrected using a fudge factor

• OT will not include DiffGainCals• Time estimates quantized by subscan duration

– Subscan duration defaults to 30s– Reduced if a large number of pointings are being observed– Integer number of mosaics

• Larger minimum on-source time?– Currently set to 2 minutes over all sources– 150 sources are allowed -> 20 s each

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

“Experimental” modes

• Were defined as projects that couldn’t be pipelined– A maximum of 25% of such projects was envisaged– However, definition is slowly expanding...

• Current list– Bands 8, 9 & 10– Bandwidth switching projects– Full polarization– Spectral Scans– Long baselines (> 1.5 km)– Ephemeris observations– Non-standard calibrations

• Will be indicated to PI on cover sheet

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

Miscellaneous

• Lots of bug fixes and small improvements• TJ will remain in OT and per SG

– Format has been improved– Copy and paste/drag and drop will work

• Ability to import and export pointing positions per source• No “point source” button• Improved time estimate dialogue• Improved time constraint interface• Multiple rectangular mosaics• And much, much more!!!

ARC Retreat 2014 – Cycle 3 Capabilities and the OT

OT Cycle-3 Timeline

• 30 Sep– Deadline for input

• 1 Dec– Deadline for final (small) changes– Some capabilities might be dropped

• 15 Dec– Code freeze

• Jan/Feb– Test, test, test

• 23 Mar– Deployment