Summary of Residual On-axis Leakage
Scope: manifest indices 14–49, excluding 24–29 (ODC-5241 era; ODC-3611 legacy fields not included).
Each table row is one (ODC weight, calibration variant, reference field) combination, aggregated over all SB_REF observations of that field.
Bandpass calibrated (bpcal) and Bandpass + Leakage on-axis calibrated (lcal) variants are shown in separate tables.
Plot badges on the Reference field column link to per-ODC and all-ODC footprint heatmaps (see legend below).
SB_REF media (Stokes/pol.degree MP4, combined-beams PNG, beamwise stats, PAF overlay and movie) are accessible
via the drop-down trigger on each SB_REF ID in the Observed SB_REF IDs column.
Column legend
Notation convention: the superscript in parentheses denotes the index (dimension) over which the statistic is computed.
For example, \(\mu^{(s)}\) = median over SB_REF observations \(s\); \(\mu^{(b)}\) = median over beams \(b\).
Subscripts denote the free indices the result depends on.
| Column | Meaning |
|---|
| ODC weight | ODC WEIGHTS ID |
| Variant | Bandpass calibrated (bpcal) or Bandpass + Leakage on-axis calibrated (lcal) |
| Reference field | Name (with skyPos) of the field used for calibration |
| n_obs(f) | Number of independent observations for this field (per ODC weight) |
| Observed SB_REF IDs | Links to the leakage statistics card for each individual SB_REF observation |
| μ⁽ᵇ⁾ | Median across beams of \(\mu_{b,f}^{(s)}\) |
| MAD⁽ᵇ⁾ | MAD across beams of \(\mu_{b,f}^{(s)}\) — beam-to-beam spread |
| min⁽ᵇ⁾ | Minimum across beams of \(\mu_{b,f}^{(s)}\) |
| max⁽ᵇ⁾ | Maximum across beams of \(\mu_{b,f}^{(s)}\) |
All statistics are over percentage linear polarisation leakage, \(dL\) (%).
\(dL = 100 \times L/I\), where \(L\) is the linear polarisation intensity and \(I\) is the Stokes I total intensity.
Plot badges on Reference field column:
dL / |dQ|,|dU| (blue) — per-ODC footprint for that row's variant;
dL≈ / |dQ|,|dU|≈ — all-ODC comparison footprint (bpcal + lcal stacked).
dL = residual leakage (dL = √(Q²+U²)/I (%)), faceted by ODC weight and calibration variant.
|dQ|,|dU| = split-circle plots of |Q|/I (top-left) and |U|/I (bottom-right).
Bandpass calibrated
| ODC weight | Variant | Reference field | n_obs(f) | Observed SB_REF IDs | μ⁽ᵇ⁾ | MAD⁽ᵇ⁾ | min⁽ᵇ⁾ | max⁽ᵇ⁾ |
|---|
| 5435 | bpcal | REF_0612-28 dL |dQ|,|dU| dL≈ |dQ|,|dU|≈ dQ∿ dU∿ | 1 | | 0.766 | 0.205 | 0.274 | 2.037 |
Bandpass + Leakage (on-axis) calibrated
| ODC weight | Variant | Reference field | n_obs(f) | Observed SB_REF IDs | μ⁽ᵇ⁾ | MAD⁽ᵇ⁾ | min⁽ᵇ⁾ | max⁽ᵇ⁾ |
|---|
| 5435 | lcal | REF_0612-28 dL |dQ|,|dU| dL≈ |dQ|,|dU|≈ dQ∿ dU∿ | 1 | | 0.451 | 0.278 | 0.084 | 1.962 |
3D Leakage cube (NetCDF4)
The leakage data is stored as a labelled 3-D NetCDF4 cube
with dimensions beam (36) × field (N) × odc (M).
Variables: dL_bpcal, dL_lcal, p90_bpcal, p90_lcal, nsb_bpcal, nsb_lcal.
Open with xarray.open_dataset('leakage_cube.nc') for programmatic slicing, outlier detection, or further analysis.
leakage_cube.nc (21 KB)
Gain Calibration Strategy
Open: Gain Calibration Strategy
— derivation of the bandpass correction factors from 1934−638 measurements.
dQ/dU Correction Factors
Per-beam leakage correction factors derived from 1934−638 observations. All three files open as plain text in a new browser tab.
