Data Taking Plans for 32T and 128T Twiki: Jump to 32TEoRObs

Key Areas to Address with 32T (Review) RFI Instrument calibration (ENG + RTS) The sky and foregrounds Where do we reach important thresholds on the way to 128T and 400-500T?

32T November Obs.

RFI—Identify, eliminate, document, mitigate RFI—Identify, eliminate, document, mitigate. We need well-developed RFI mitigation systems in place at the beginning of EOR operations with the full array. Beginning with 32T we can: Identify sources of RFI that we can control (on-site, local, or otherwise covered by the radio-quiet legislation) and eliminate them Document the characteristics of low-level RFI Better than ED 10 hour limit Spectral occupancy as a function of integration time Temporal frequency and duration of meteor and aircraft reflections, sporadic-E propagation events in the ionosphere, tropospheric events, and other temporal variations What can we expect on short baselines? Develop, implement, test, and demonstrate an RFI mitigation system (including any custom hardware, real-time software, etc.)

Instrument performance Instrument performance. Alleviate concerns related to the calibration and performance of the array and/or identify areas that need attention. Characterize the performance of the antenna tiles (variations in beam patterns, gain, stability; interactions between closely packed antenna tiles; walsh function behaviors; noise from beamformer delay switching) Characterize the intensity and polarization calibration Characterize the ionospheric distortions and calibration, including as a function of the severity of ionospheric distortions. What is the typical expectation? What extremes can be tolerated? How often do they occur? Determine best limits on observing conditions. Do the Sun and Galactic center need to be below the horizon? Can we observe down to a zenith angle limit of 45 degrees? What is the loss in performance as a function of zenith angle? Implement and test EOR-specific real-time software, then demonstrate that our plans for data compression (temporal integration, gridding/mapping, etc.) can be performed without degrading the signal.

The sky and foregrounds The sky and foregrounds. Fill gaps in our knowledge about the astrophysical sky as early as possible so that we can confirm that our candidate target fields are the best choices and assess our analysis plans. Demonstrate that existing sky maps can be used to adequately predict the intensity of the 100-200 MHz sky Detect and characterize the diffuse polarized foreground component in our target fields It would be advantageous to have a (even crude) sky model early on for developing and implementing data analysis strategies.

Astrophysical Sky: Assemble "all-sky" survey - Ord, Bowman Characterize long integration Noise vs. integration time - Bowman et al. RRLs - Bowman et al., GEG (Robishaw), Shep Polarized emission - Gaensler, Geil, GEG? Continuum - Bowman et al., GEG? Test foreground subtraction Peeling - Mitchell, Wayth Bright sources - Pindor Confusion-level sources - Bowman Characterize whatever is left vs. models/simulations - Bowman et al. Sky model (from survey and target field) - de Oliveira Costa, Bowman, Gaensler, RTS Assess planned EoR fields for 512T campaigns - Bowman, Gaensler

Technical assessment status: (X2.5 - X5) System temperature as the full analog/digital pipeline is deployed – TBD (Bowman) (X3) Make single-tile sky maps of Galactic emission as preliminary test of beamformer and antenna patterns – TBD (Williams) (X3 - X5) Antenna patterns from satellites and discrete sources, including high-spectral resolution with rapid dipole switching – Ongoing (Mitchell) (X3? - X5) Walsh function switching in interferometric observations – Waterson on bench/TBD in obs. (X3 - X5) Measurement of RFI generated in the digital system (and other systems) - TBD (X3 - X4) Interferometric determination of tile locations (and second-order ionospheric effects) – done (Randall?)

A revised plan Originally: Now: We had planned an EoR-focused 100 hour (2-week) observing run with 32T. Now: For April-June our goal should be 2-nights on the same field for full 6-hour tracks? Save long integration for 128T?