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[1007.5307] On the suspected timing-offset-induced calibrat

Posted: July 30 2010
by Tom Shanks
This looks to be an interesting paper by Boud Roukema, following up on earlier discussions in this forum. He suggests that the 25.6ms timing offset issue in the WMAP time-ordered data raised by Liu & Li (2010, 0907.2731) could still apply to the step of calibrating the WMAP data and produces evidence based on minimising large pixel variance as a function of timing offset. He argues that his method makes it possible to pick out the timing offset that was used in the calibration step and that his result favours the Liu and Li offset rather than the WMAP team offset. Previously Boud (1004.4506) had shown in a different analysis using source profile sharpness that the WMAP team offset was likely to have been properly applied at the map-making stage. The question now is whether an improperly applied offset at the calibration stage could still explain the anomalies associated with the low-l multipoles in the WMAP data and also those at small scales associated with the wider than expected WMAP radio source profiles found by Sawangwit & Shanks (2010, 0912.0524). Comments?