2015 Timelines

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General description

The timelines, or TOIs for Time-Ordered Information, are vectors of signal or of pointing or of some other quantity giving the value of that quantity as a function of time during the mission. For LFI(Planck) Low Frequency Instrument, refer to Planck-2015-A02[1], and for HFI(Planck) High Frequency Instrument, to Planck-2015-A07[2].

The TOIs described here are sampled regularly at the (instrument dependent) detector sampling frequency and span the full science mission. They thus consist of a large amount of data. This section is concerned with the signal TOIs and their associated pointing TOIs. For selected detectors the DPCs provide a single timeline of cleaned and calibrated signal and 3 timelines of coordinates, corresponding to the two angular coordinates and one position angle.

Obviously these vectors are very long (~1.38E10 samples for HFI(Planck) High Frequency Instrument, from ~2.5E06 to ~5.5E06 for LFI(Planck) Low Frequency Instrument) and thus need to be split into multiple files for export. Here the data are split by Operational Day (ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day.) as follows:

  • HFI(Planck) High Frequency Instrument: 12 files per ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day., one for pointing and one for signal for each channel, covering ODs 91 -- 974, all sampled at Fsamp = 180.3737 Hz.
  • LFI(Planck) Low Frequency Instrument: 6 files per ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day., 3 each for signal and pointing, since the sampling frequency is channel dependent, and covering ODs 91 -- 1543, sampled at Fsamp = 32.5079, Fsamp = 46.5455 and Fsamp = 78.7692 Hz.

The signal timelines are encoded as Real*4, but the pointing vectors had to be encoded as Real*8 to maintain the required accuracy. The result is that the total volume of the full dataset is ~30 TB. All files also contain the OBTOn-Board Time.

The signal timelines have been cleaned of all known instrumental systematic effects, they have been calibrated in flux, and the solar and earth motion dipole signals have been removed. But they have not been cleaned of the low-frequency, 1/f noise that needs to be removed via a destriping tool. The methods consists of removing offsets or baselines determined by minimizing the differences in the signals at points on the sky where they intersect. For HFI(Planck) High Frequency Instrument an offset per ring is determined; for LFI(Planck) Low Frequency Instrument the the baseline is computed every 0.246, 0.988 and 1.000 second for the 30, 44 and 70 GHz respectively and maintain the same structure of the signal timelines. In case of HFI(Planck) High Frequency Instrument these offsets are determined using the full mission and all the valid detectors per channel, and they are then used for all the maps produced, i.e., for those maps using any fraction of the mission (year, survey) or any subset of the detectors (single detector, detector set), and it was shown that using offsets determined from a limited part of the mission and/or a subset of the detectors yields maps that are less consistent than otherwise.

In case of LFI(Planck) Low Frequency Instrument these offsets are determined using the full mission and all the valid detectors per channel, those values has been used for the production of the full mission period maps. Note that baseline used for shorter period maps are determined on those data period to avoid noise cross-correlation effect and those are not delivered.

The offsets are delivered separately, as described below.

Furthermore, for HFI(Planck) High Frequency Instrument and LFI(Planck) Low Frequency Instrument, there are three sets of offsets produced: the primary set using the full rings, and the secondary ones using the first and second half rings, only. The difference between the primary and the secondary sets are fairly minor, but they are necessary to rebuild the maps as they were built by the HFI(Planck) High Frequency Instrument-DPCData Processing Center and LFI(Planck) Low Frequency Instrument-DPCData Processing Center. Overall the offsets are useful for users wishing to build a map of a small area of the sky.

The HFI(Planck) High Frequency Instrument delivers its offsets in a ROIRing-Ordered Information (DMC group/object), or "Ring-Ordered Information" file. That file contains a table of Nrings = 26766 rows by Nbolometers in which each cell contains a 3-elements vector containing the full-ring, first half-ring, and second half-ring offsets. The indices of the signal TOI delimiting the rings are given in a second ROIRing-Ordered Information (DMC group/object) file with the same Nrings rows containing global parameters.

The LFI(Planck) Low Frequency Instrument delivers its offsets in a TOI format, the structure is EXACTLY the same used by the Science Timelines. The user can simply subtract one-by-one the offset timelines from the Science Timelines and then generate a map with the result. In case of the half-ring baseline, a vector has been added in the OBTOn-Board Time extension; this vector contains 1 or 2 depending to which half ring should be applied.

HFI(Planck) High Frequency Instrument Indexing

Each FITSFlexible Image Transfer Specification file contains keywords giving the first and last index of the section of the full TOI contained in the file. These indices are those of the internal DPCData Processing Center representation; they begin at 0 corresponding to the switch-on of the instrument, and run to some very large number (~25 billion for HFI(Planck) High Frequency Instrument) representing the full mission. Only the science part of the mission is exported, which is about 60% of the total for HFI(Planck) High Frequency Instrument. Are left out the early mission phase (cool-down and validation phases) and the warm phase of HFI(Planck) High Frequency Instrument, during which LFI(Planck) Low Frequency Instrument continued to collect data. The HFI(Planck) High Frequency Instrument keywords also indicated which rings are included in each ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day., but be aware that normally an ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. does not begin at the same time (with the same index) as a ring.

Note that for historical reasons, the ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. definitions of the two DPCs differ: for LFI(Planck) Low Frequency Instrument they occur at the transition between pointing periods, whereas for HFI(Planck) High Frequency Instrument they do not. This has however no significant importance for the user, as this splitting is somewhat arbitrary anyway, and what counts is the full vector once it is rebuilt in the user's own work space.

HFI(Planck) High Frequency Instrument timelines at the DPCData Processing Center are indexed from 0 to ~25E9, that correspond to instrument switch-on to switch-off. Of these the indices ~1.4E9 to 151.5E9 correspond to the science mission and are exported and delivered. Each file contains a keyword giving the first and last index of the data in that file, and EndIndex(ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day.)+1 = BeginIndex (ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day.+1). The ROIRing-Ordered Information (DMC group/object) Global file gives the Begin/End Indices of each Ring, or Pointing Period, and can be used to destripe the signal TOIs with the offsets provided in the Destriping-Offsets ROIRing-Ordered Information (DMC group/object) file.

Production process

HFI(Planck) High Frequency Instrument processing

The input TOIs are in ADUs representing the voltage signal at the end of the electronics (see Detection chain for details). The processing applied to remove instrumental effects and to calibrate them is described in detail in the HFI TOI processing section, and in Planck-2015-A07[2] we give a very brief summary here for convenience. That pipeline performs the following operations:

ADCanalog to digital converter correction
corrects for the uneven size of the ADCanalog to digital converter bins (see ADC correction).
demodulation
this is performed around a variable level which is determined from the valid input data (using a validity flag from a previous version of the processing), and the data are converted to engineering units (V) using known conversion coefficients.
despiking
the redundancy within a ring is used to determine where glitches occur. Once identified, the glitches are fitted with templates. A glitch flag is produced that identifies the strongest part of the glitches, and a timeline of glitch tails. produced from the template fits, is subtracted from the demodulated timeline. Finally, the flagged regions are replaced with data from an average over the pointing period in order to not leave holes in the timeline that would perturb the usage of Fourier methods on them
dark template removal
the two dark bolometers are demodulated and despiked as above; the resulting timelines are then smoothed and used as an indicator of the overall temperature variations of the bolometer plate. Where the variations are consistent with each other, they are combined and removed from the bolometer signal timelines using appropriate coupling coefficients. The few percent of the data where they are not consistent are flagged as not valid on the timelines.
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: the electromagnetic interference of the 4K cooler with the bolometer readout wires induces some sharp lines in the signal power spectra at frequencies of the 4K cooler's fundamental and its multiples, folded by the signal modulations. Fourier coefficients of the relevant lines are determined on a per-ring basis, and then removed from the data. The quality of the removal depends on the bolometer.
deconvolution by the time transfer function
this is done to correct for the non-instantaneous time response of the bolometers. The function itself is modeled using up to 8 time constants which are adjusted primarily on the planet data and also from comparisons of the northward and southward scans of the Galactic Plane. It is then removed using Fourier techniques.
jumpsudden change of the baseline level inside a ring correction
corrects some pretty rare jumps in the signal baseline (there are on average ~ 0.3 jumps per bolometer per pointing period). The jumps are detected and characterised on smoothed TOIs, and corrected by adding a constant to part of the signal timeline. The origin of the jumps is not known.

The results of this processing are a timeline of signal (in absorbed watts) and a valid data flag timeline for each of the 50 valid bolometers which are processed, out of the 52 HFI(Planck) High Frequency Instrument bolometers; these timelines contain the full sky signal, i.e., including the solar and orbital dipoles, the Zodiacal light, and contributions from the Far-Side lobes. The dipoles are necessary for the flux calibration and are removed at the mapmaking stage. The remaining two bolometers (143-8 and 545-3) show semi-random jumps in the signal level, typically jumping over 2-5 different pseudo-baseline levels, a behavior known as Random Telegraphic Signal, so that these are commonly called the RTSrandom telegraphic signal bolometers. Finally, ring-level statistics of different types (mean, median, rms, kurtosis, etc.) are determined on a per-ring basis for all timelines, and a selection based on these statistics is used to discard anomalous rings, which are recorded in a ring-level flag for each valid bolometer timeline (see the Discarded rings section).

Throughout this processing, some planet signals are masked in the timeline in order to avoid ringing effects in the processing. It concerns only Jupiter at 100 and 143 GHz, Jupiter and Saturn at 217 GHz, Jupiter, Saturn and Mars at 353, 545 and 857 GHz (thanks to various improvements in the despiking and in the transfer functions it is no longer necessary to flag these three planets in the CMBCosmic Microwave background channels as was done in Release 1). Since they move on the sky, the portion of the sky masked during one survey is observed during another one, and no hole is left in the final map. In parallel, the planet data are processed in a similar way, but with different parameters for the despiking step. These results are processed separately to determine the beam shapes and the focal plane geometry.

Next, the TOIs are calibrated in astrophysical units using the results of the calibration pipeline (see the Map-making and calibration section) and the best estimate of the zero-point offsets (a constant level for each bolometer). These values are given in the RIMOreduced IMO. Also, the solar and earth-motion dipole signals are computed and removed.

These TOIs are accompanied by several flags that are described below. The most important one is the Total flag, which identifies all the samples that were discarded by the DPCData Processing Center mapmaking, ad described in HFI TOI processing. This flag includes the portion beyond 72 min for the rings that are longer, which is not used because of the slight drift of the satellite pointing direction (spin axis) during these long acquisition periods.

At this point the TOIs still contain the low frequency (1/f) noise which should be removed before projection onto a map. That cleaning step is called "destriping" "baseline removal". The HFI(Planck) High Frequency Instrument-DPCData Processing Center does its destriping at ring-level, meaning that a constant is added to the signal of each ring in order to minimise the difference at the ring crossings, where the signal should be the same for all detectors (with the necessary precautions as described in Map-making and calibration section); should the user want to use the DPCData Processing Center's offsets, they are provided separately (see ROI files below). Maps produced from these TOIs, and after subtraction of the DPCData Processing Center's destriping offsets, are not identical to the maps delivered. This is discussed in Section A.2 of Planck-2015-A08[3].

As indicated above, the brightest planets are masked in the TOI in order to avoid ringing problems. For users wanting to study specifically these planets, we provide separate timelines covering just the planet transits. These timelines include also transits of Uranus and Neptune, which are not masked in the regular TOIs. These timelines are produced with less agressive deglitching options in order to work on the rapidly changing baselines. These are the data used the reconstruction of the focal plane geometry and also for the determination of the scanning beams.

The table below lists the 16 transits, giving for each the begin/end ring and the begin/end ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. in which that ring is found. Note that transit 15 is split in two parts because some tests were done during the transit. The 18th row is a region processed in the same manner but without a planet transit, which is included for comparison.

Planet transits
Number BegRing EndRing Beg ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. End ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Comment
1 2700 3211 160 176 Jup, Mar, Nep
2 3892 4099 203 212 Ura
3 4575 4775 233 240 Sat
4 7900 8150 330 337 Mar
5 8979 9188 367 376 Nep
6 9550 9750 392 402 Sat
7 9940 10300 411 425 Jup, Ura
8 14018 14227 537 544 Nep
9 14820 15190 567 583 Jup, Ura
10 15925 16275 612 624 Sat
11 20016 20225 734 743 Nep
12 20900 21650 775 804 Sat, Ura
13 21780 22150 808 818 Jup
14 24992 25202 916 921 Nep
15a 25830 25849 937 938 Mar, Ura
15b 25864 26225 947 957 idem
16 26650 27005 968 974 Jup
17 12000 12150 479 483 background


The pointing (see common Detector Pointing section for details) is determined from the AHFAttitude History File produced by MOC[ESA's] Mission Operation Center [Darmstadt, Germany], which gives the direction and orientation of the LOSLine Of Sight of a fiducial position in the focal plane at frequencies of 8Hz during stable pointing and 4 Hz during maneuvers. This is interpolated to the timestamps of data samples, 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 LOSLine Of Sight of each detector using the quaternions in the IMO. These pointing data are valid for both the regular and the Planet TOIs.

LFI(Planck) Low Frequency Instrument processing

The input TOIs are in ADUs representing the voltage signal at the output of the electronics (see Radiometer Chain Assembly (RCA) for details). The processing applied to remove instrumental effects and to calibrate them is described in detail in the LFI TOI processing section, and in Planck-2015-A03[1] we give a very brief summary here for convenience. That pipeline performs the following operations:

ADCanalog to digital converter correction
due to ADCanalog to digital converter non-linearity under certain condition, this instrumental effect is removed by applying well know templates directly to the diode signal.
Electronics Spikes
caused by the interaction between the electronics clock and the scientific data lines. The

signal is detected in all the LFI(Planck) Low Frequency Instrument radiometers' time-domain outputs as a 1s square wave with a rising edge near 0.5s and a falling edge near 0.75s synchronous with the on-board time signal. In the frequency domain it appears as a spike signal at multiples of 1 Hz. The 44 GHz channels are the only LFI(Planck) Low Frequency Instrument outputs significantly affected by this effect. Consequently the spike signal is removed from the data only in these channels.

Demodulation
each LFI(Planck) Low Frequency Instrument diode switches at 4096 Hz between the sky and the 4K reference load. The data acquired in this way is dominated by 1\f noise that is highly correlated between the two streams; differencing those streams results in a strong reduction of 1\f noise. The procedure applied is described in LFI TOI processing taking into account that the gain modulation factor R was computed on timestreams with the Galaxy and point sources masked to avoid strong sky signals.
Diode combination
two detector diodes provide the output for each LFI(Planck) Low Frequency Instrument receiver channel. To minimize the impact of imperfect isolation of the data stream of each diode, we perform a weighted average of the time-ordered data from the two diodes of each receiver. The procedure applied is detailed in LFI TOI processing; the weights used are kept fixed for the entire mission.
Scientific Calibration
calibrate the timelines to physical units KCMBCosmic Microwave background, fitting the total CMBCosmic Microwave background dipole convolved with the 4pi beam representation, without taking into account the signature due to Galactic straylight;
Gain regularization
the calibration constants computed using the model of the dipole signal suffer from large uncertainties when the Planck spacecraft is badly aligned with the dipole axis. To reduce the noise, we apply an adaptive smoothing algorithm

that is also designed to preserve the discontinuities caused by abrupt changes in the working configuration of the radiometers (e.g., sudden temperature changes in the focal plane).

Removal of solar and orbital dipole signal
the combined solar and orbital dipole is convolved with the 4pi beam representation of each radiometer and the removed from its timeline.
Removal of Galactic Straylight
the light incident on the focal plane without reflecting on the primary mirror (straylight) is a major source of systematic effects, especially when the Galactic plane intersects the direction of the main spillover. This effect is corrected by removing the estimated straylight signal from the timelines. This signal is computed as the convolution of Galaxy simulation with the beam sidelobes, see details in LFI TOI processing.

At this point the timelines are used for the production of the maps.

The pointing (see common Detector Pointing section for details) is determined from the AHFAttitude History File produced by the MOC[ESA's] Mission Operation Center [Darmstadt, Germany], which gives the direction and orientation of the LOSLine Of Sight of a fiducial position in the focal plane at frequencies of 8Hz during stable pointing and 4 Hz during maneuvers. This is interpolated to the timestamps of data samples, corrected for the wobble and other time-dependent offsets determined from the observed positions of a large number of sources around the sky and temperature sensor, and finally converted to the LOSLine Of Sight of each detector.

File Names

The file names are of the form:

{H,L}FI_TOI_{fff}-{SCI,PTG,TAI,OFF}_R2.nn_ODxxxx.fits

where

  • fff denotes the frequency
  • SCI denote signal TOIs
  • PTG denote pointing TOIs
  • TAI denote OBTOn-Board Time-MJD correlation TOI
  • OFF denote Baseline TOI
  • R2.nn is the version, and
  • ODxxxx indicates the ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day..

Regarding the HFI(Planck) High Frequency Instrument TOIs for the 100-217 channels, the R2.00, made public in Jan 2015, contained only the unpolarised bolometer timelines, while R2.02, made public in July 2015, contains all bolometers.

The HFI(Planck) High Frequency Instrument Planet timelines are named:

{H,L}FI_TOI_{fff}-SCI-planets_R2.nn_ODxxxx.fits

and are provided for all 50 valid bolometers, i.e., SWBs and PSBs.

FITSFlexible Image Transfer Specification file structure

All FITSFlexible Image Transfer Specification files begin with a primary extension containing no data and a minimal header, which is followed by one or more BINTABLE extensions with data, and with a description of the data in the header keywords. In what follows will usually ignore the primary extension, and count only the extensions containing data.

TOI files

The signal FITSFlexible Image Transfer Specification files contain N+1 ,'BINTABLE', data extensions, where N is the number of detectors in that frequency channel. The first extension contains the OBTOn-Board Time and its flags, called the global flags since they apply to all detectors, which is followed by one extension for each detector, containing the signal and its local flag. The flags columns are written as byte in which each of the 8 bits (max) encodes one flag timeline. The meaning of each bit is given in the header comments and is subject to change. For the global flag they include:

  • HFI(Planck) High Frequency Instrument
    • Unstable pointing: 1= pointing is not stable (e.g., during repointing maneuvers)
    • Dark correlation: 1 = darks are uncorrelated and data are flagged
    • First/Second half ring: which samples are in which half (only covers the stable pointing part of the ring)
    • HCMAngular momentum Control Mode: in HCMAngular momentum Control Mode mode (unstable pointing)
    • and more - see extension header for details
  • LFI(Planck) Low Frequency Instrument
    • Bit 0, unstable pointing: 1= pointing is not stable
    • Bit 1, time correlation quality: 1= outside specification
    • Bit 2, special observation: 1= special observation like deep scan

And for the local flag they include

  • HFI(Planck) High Frequency Instrument
    • Total Flag: a combination of the various flags that is the one finally used in the map-making (all samples with Total Flag different from zero should not be used)
    • Data not valid: glitched samples
    • Despike Common: (for PSBs only) glitch on current or other of PSB pair
    • StrongSignal: on Galactic Plane
    • Strong Source: on point source
    • and more - see extension header for details
  • LFI(Planck) Low Frequency Instrument
    • Bit 0, Data not valid: 1= Science sample not valid
    • Bit 2: Planet crossing: 1= Science Sample containing planet
    • Bit 3: Moving objects: 1= minor Solar System object (not yet used)
    • Bit 4: Gap: 1= this sample was artificially included due to gap in the data

for HFI(Planck) High Frequency Instrument, the header extension gives more details on the flags and the meaning of 1 / 0.

TOI file data structure
1. EXTNAME = 'OBTOn-Board Time' : Data columns
Column Name Data Type Units Description Comment
OBTOn-Board Time Double 2-16 sec On-board time
FLAG Byte none the various bit-level flags
Keyword Data Type Value Description Comment
ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Int ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. covered (as in filename)
BEGIDX Int first sample index of given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
ENDIDX Int last sample index of given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
BEGRING Int first ring in given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
ENDRING Int last ring in given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
TIMEZERO String 1958-01-01z00:00 Origin of OBTOn-Board Time Only HFI(Planck) High Frequency Instrument
TIMEZERO Float 106744000000000. Origin of OBTOn-Board Time Only LFI(Planck) Low Frequency Instrument
n. EXTNAME = DETNAME : Data columns
Column Name Data Type Units Description Comment
SIGNAL Real*4 Kcmb or MJy/sr Value of signal Comment
FLAG Byte none the various bit-level flags
Keyword Data Type Value Description Comment
UNIT String Units of signal Only HFI(Planck) High Frequency Instrument, LFI(Planck) Low Frequency Instrument always Kcmb
DESTRIPE 1/0 whether timeline is destriped Only HFI(Planck) High Frequency Instrument
ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Int ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. covered (as in filename)
BEGIDX Int first sample index of given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
ENDIDX Int last sample index of given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
BEGRING Int first ring in given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument
ENDRING Int last ring in given ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. Only HFI(Planck) High Frequency Instrument

The HFI(Planck) High Frequency Instrument Planet files have the same structure, but the local flags contain a single "Data not valid" flag. Also, the first and last ODOperation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day. of each transit is usually not complete, as they contain only the rings that are included in the transit observations.

The pointing files have a similar structure, except that DETNAME extensions contain 3 columns of Real*8 with the phi, theta, and psi Galactic spherical coordinates of each sample in radians, as shown in the table below. There is no local flag for the coordinates.

Pointing TOI file DETNAME extension structure
n. EXTNAME = DETNAME : Data columns
Column Name Data Type Units Description
PHI Real*8 radian longitude
THETA Real*8 radian colatitude
PSI Real*8 radian roll angle

HFI(Planck) High Frequency Instrument ROIRing-Ordered Information (DMC group/object) files

The files provided by HFI(Planck) High Frequency Instrument are

  • HFI(Planck) High Frequency Instrument_ROIRing-Ordered Information (DMC group/object)_GlobalParams_RelNum_full.fits
  • HFI(Planck) High Frequency Instrument_ROIRing-Ordered Information (DMC group/object)_DestripeOffsets_RelNum_full.fits

which are described below.

Global parameters
this ROIRing-Ordered Information (DMC group/object) file contains a single BINTABLE extension with 3 columns that give, for each ring, the index number of the first sample, the ESAEuropean Space Agency pointing ID of the ring, and the ring start time. All three are encoded as Int*8, and the time is given in units of 2-16 sec from TIMEZERO, 1958-01-01z00:00, as in the TOI files. Rings are numbered from 240 to 27005, as given in the BEGRING and ENDRING keywords
Destriping offsets
this ROIRing-Ordered Information (DMC group/object) file contains a single BINTABLE extension with 3 columns that give, for each ring, the offsets to subtract from each bolometer signal timeline or vector. There are three offsets available for each bolometer: full-ring, first half-ring, and second half-ring, for building the full-ring or the two half-ring maps, respectively. The offsets must be subtracted from Index(N) to Index(N+1)-1 of the corresponding signal timeline, where N is the ring number, and the indices are given in the Global parameters file. The offsets are given in the same units as the signal vectors, that is Kcmb for the 100-353 GHz channels, and MJy/sr for the 545 and 857 GHz channels. All values are encoded as Real*4. The rings for which the offsets are set to 0.000 are badrings which are rejected in the mapmaking process. These rings are also flagged by the TotalFlag, as are the portions of rings longer than ~72.5 min, where the drift in the satellite's spin axis becomes important.

TAI TOI files

The TAI TOI files contains one extension with two column, the first is the OBTOn-Board Time value (exactly the same reported in the SCI TOI), the second the corresponding Modified Julian day. Note that Leap second where not added.

Time TAI TOI file data structure
1. EXTNAME = 'OBTOn-Board Time-MJD' : Data columns
Column Name Data Type Units Description Comment
OBTOn-Board Time Int*8 2-16 sec On-board time
MJD Real*8 day Modified Julian day

LFI(Planck) Low Frequency Instrument OFF TOI files

The OFF (baseline) TOI files adopt the same file structure of the Science TOI files. Note that in case of OFF timelines related to the half-ring, and addition column in included in the OBTOn-Board Time extension to define for each sample if it belong to half-ring 1 or half-ring2.

LFI(Planck) Low Frequency Instrument HouseKeeping files

House keeping timelines are:

  • LFI(Planck) Low Frequency Instrument_TOI_DAELFI Data Acquisition Electronics-FAST-HKHouse Keeping_R2.nn_ODxxxx.fits
  • LFI(Planck) Low Frequency Instrument_TOI_DAELFI Data Acquisition Electronics-SlowConfiguration-HKHouse Keeping_R2.nn_ODxxxx.fits
  • LFI(Planck) Low Frequency Instrument_TOI_DAELFI Data Acquisition Electronics-SlowCurrent-HKHouse Keeping_R2.nn_ODxxxx.fits
  • LFI(Planck) Low Frequency Instrument_TOI_DAELFI Data Acquisition Electronics-SlowPhaseSwitch-HKHouse Keeping_R2.nn_ODxxxx.fits
  • LFI(Planck) Low Frequency Instrument_TOI_DAELFI Data Acquisition Electronics-SlowVoltage-HKHouse Keeping_R2.nn_ODxxxx.fits
  • LFI(Planck) Low Frequency Instrument_TOI_REBALFI Radiometer Electronics Box Assembly-HKHouse Keeping_R2.nn_ODxxxx.fits
  • SCSSorption Cooler Subsystem (Planck)_TOI_EssentialASW-HKHouse Keeping_R2.nn_ODxxxx.fits
  • SCSSorption Cooler Subsystem (Planck)_TOI_NonEssentialASW-HKHouse Keeping_R2.nn_ODxxxx.fits

Each file contains two extension, the first is the OBTOn-Board Time (value are sampled at 1 or 10 seconds), the latter contain a variable number of column = 2* number of HouseKeeping stored. Each Housekeeping is accompanied by its flag (normally 0 is NOT 0 the value was considerate invalid or Out Of Limit). The Housekeeping name are the once defined in the LFI(Planck) Low Frequency Instrument Instrnument Operation Manual.

References

  1. 1.0 1.1 Planck 2015 results. II. LFI processing, Planck Collaboration, 2016, A&A, 594, A2.
  2. 2.0 2.1 Planck 2015 results. VII. High Frequency Instrument data processing: Time-ordered information and beam processing, Planck Collaboration, 2016, A&A, 594, A7.
  3. Planck 2015 results. VIII. High Frequency Instrument data processing: Calibration and maps, Planck Collaboration, 2016, A&A, 594, A8.