Timelines

There will be no timelines in the 1st data release …

Semi-raw signal timelines

HFI timelines

Originally defined to be the raw (ADU) data demodulated and converted to engineering units (V) via the HFI transfer functions (includes 3-pt filtering?). But (1) this is not the same demodulation method as used in the TOI prod pipeline, and (2) the ADC correction (or at least one method thereof) implies a modification of the raw data before demodulation. Thus what the HFI will deliver is not yet decided

LFI timelines

TBW

Cleaned and calibrated signal timelines

HFI processing

The calibrated timelines are produced by the TOIprod pipeline (link to wiki; link to paper) which in brief performs the following operations:

demodulation

this is performed around a variable level which is determined from the valid input data (a validity flat from a previous version of the processing is determined for this purpose), and the data are converted to engineering units (V) using known conversion coefficients.

despiking

using the demodulated data converted to V (by the transfer function) the glitches are identified and fitted with templates. A glitch flag is produced that identifies the strongest part of the glitches, and a timeline of glitch tails is produced from the template fits, and subtracted from the demodulated timeline from step 1. Finally, the flagged ranges are replaced with data from TBC (is this done here, if not where?)

dark template removal

TBW

conversion to absorbed power

the timeline is converted to watts of absorbed power using the bolometer function. This includes a non-linearity correction

removal of the 4K cooler lines

TBW

at this point a timeline in W and a glitch flag are written to disk

deconvolution by the time transfer function

TBW

jump correction

removes some (relatively rare) jumps in the signal baseline

at this point a tau-deconvolved and jump-corrected timeline and its associated glitch flag are written to disk. These timelines are later used in the flux calibration and mapmaking stages

Note that these timelines contain the full sky signal, i.e. including the solar and orbital dipoles and the Zodiacal light. The dipoles are necessary for the flux calibration and are removed by the pipeline at the mapmaking stage.

Need to discuss dipoles removal and conversion to astrophysical units at the export stage

Pointing timelines

The pointing is determined starting from the AHF produced by MOC, which gives the direction and orientation of the LOS of a fiducial position in the focal plane at frequencies of 8Hz during stable pointing and 4 Hz during maneuvers (TBC for details, reference). This is interpolated to the times of data observation (ref to method), corrected for the wobble and other time-dependent offsets determined from the observed positions of a large number of sources around the sky, and finally converted to the LOS of each detector using the quaternions in the IMO (which are determined from observations of bright planets - see the Focal plane reconstruction pipeline).

Details of delivery are TBD

FITS file structure

TBW