Deconvolution/source subtraction via forward modeling

(Pindor et al., 2011, PASA, 28, 46)(GB et al., 2011, MNRAS, 413, 411)

•It can now run on the instrumental polarization -> speed increases proportional to the length of the integration

•It accounts for the pixel noise statistics

Deconvolving real data: an example

Source J0523-36 is modeled in the same

way that the pointing is processed via the RTS

(beams, cadence, frequency)

Convergence after 2 iterations. Positional

error ~ 15’, flux error ~ 10%

Primary beam measurements

• the sky drifts overhead while the tiles point at zenith;

• ~30 bandwidth centered @ 185 MHz;

• snapshot images (one every 5 min) are used to measure the beam response towards the J0444-2905 (which is ~ 37 Jy @ 185 MHz);

Primary beam measurements

J0444-2905

Fitting a simple primary beam model

The beam is accurate at a 2% leveland predicts the source fluxex with 5% rms accuracy

The rms is 0.63 Jy/beam

Stokes I

The rms is 41 mJy/beam

Stokes Q

The rms is 28 mJy/beam

Stokes U

Extending the beam work: zooming in to HydA field

HydA

Observations span slightly more than 5 hours (total) over 110-200 MHz:21 tiles available

HydA provides the direction independent calibration of the arraySnapshot images co-added

Multi-frequency synthesis (but in the image plane)

to be continued

with existing data

with X16