Overview, Spectrometer Products and Processing Philosophy Phil Appleton on Behalf of PACS Team PACS IFU Spectrometer

PACS Spectrometer: The First IFU to L2!

Simultaneous Blue and Red Coverage via diachroic GeGa Two (25 x 16) arrays Stressed and un- stressed 5x5 pixels 1 pixel = 9.4” FOV 47”x47” PACS Integral Field Spectrometer (Poglitch et al. 2010) PACS Integral Field Spectrometer (Poglitch et al. 2010) Blue (55-98  m) Selectable band (3 rd and 2 nd Order) Red (  m) 1 st order SLICER MIRRORS GeGa detectors

PACS—Some Optical Components Calibration grey-body source (common with Photometer) Filter wheel assembly Chopper (common) max 6 arcmin throw Lithrow-mounted Grating recieves elliptical beam from anomorphic collimator 8.5 grooves/mm 2720 grooves

Diffraction grating spectrometer with high- and low- stressed Ge:Ga detector arrays Grating: diffraction element used in 3 orders

The Ge:Ga Photoconductor Arrays Stressed (R) and unstressed (B) photoconductors cooled to 1.65K in a linear segments of 16 form the basic 25 spatial modules with 16 spectral pixels. The photoconductors are read-out at 256Hz via cold amplifier/multiplexer (CRE) CMOS circuit held at 3-5K. A complete assembled Ge:Ga detector assembly. Data is read out in 32 samples and slopes are fitted onboard to produce samples of 1/8s each for storage and transmission to the ground.

Line Spectroscopy AOT: observation of individual narrow lines: PIPELINE –Chopping/nodding STANDARD (SLICED) PIPELINE –Pointed, dithered and mapping modes (optional special pointed) pipeline) –For isolated sources and rasters ≤ 6 arcmin –Variable grating sampling for faint and bright linesUnchopped mode UNCHOPPED PIPELINE (Under dev) –For mapping observations of crowded fields –ON and OFF Source position provided Range Spectroscopy AOT: observation of extended ranges, broad lines or continuum STANDARD (SLICED) PIPELINE –Range scan (same concept as Line Spectroscopy) for broad lines –SED mode for continuum-like spectral scans covering huge range –Chopping/nodding –Pointed, dithered and mapping modes –For isolated sources and rasters ≤ 6 arcmin –Unchopped mode UNCHOPPED PIPELINE (Under dev) –For mapping observations of crowded fields –Optional off-position Spectrometer Astronomical Observing Templates (AOTs) Signal modulation Techniques Signal modulation Techniques Range definition -

Example of Chop/nod AOT blocks Line1 x sec Calib. 87 sec Line2 x sec Line3 x sec Line1 x sec Line2 x sec Line3 x sec … move to next raster position and repeat On-target slewNodding “A” position Nodding “B” position Nod slew Repeat N times (number of cycles) 984 sec START observation END observation Pointing layout example of a nodding raster observation: Chopping/nodding pattern Nod “A” Nod “B” = grating up-down scan OFFON OFF Nod “B” Nod “A”

Spectrometer Data PACS raw data is integration ramps with typically – 1/8 second reset interval (32 readouts) for bright sources/lines – the dynamic range can be adjusted by four integration capacitors On-board averaging is required to fit within the allowed downlink telemetry rate – 32 readouts averaged – several “raw” ramps are downloaded in their entirety to provide “saturation” information. The raw pixels cycle through the array with time. 9 PACS raw ramps

Level 0 first processing 10 PACS data, House Keeping PACS data, House Keeping Assign RA/Dec > pixel Pointing Level 0 Spectrometer Pipeline Flag Data Permanently Bad pixels (few) When grating or chopper moving Saturated data When glitches present Open and dummy channels (spec 0, 18) Convert DNs to Volts/s Assign observing block labels (e. g. Nod positions, grating scan direction, calibration block, scan mode) Level 0.5 Uncalibrated Data Frame

Steps to Calibrated Frame Wavelength Calibration Nonlinearities and Spatial Distortions Apply RSRF Flat Field correction Subtract On and Off Chop and Convert to Jy Subtract On and Off Chop and Convert to Jy 11 Level 0.5 Transient Corrections Level 1 Calibrated Data Frames (25 x 16 x time = grating movement) Under investigation

12 Calibrated Frame is time history of spectral scan as seen by each pixel 25 spatial pix 16 spectral Time FRAMES What are Level 1 Frames?

{ Grating scan = time 25 spatial pixels 16 spectral pixels RAMPS → FRAMES averaged ramps provide frames

Level 0 -1 and 2 Products SINGS background FRAMES RAW Level 0 To Level 0.5 PACS PIPELINE CUBE BUILDING To calibrated L1 FRAMES Projected to 3” x 3” pixels Level 1 Level 2 CALIBRATED PACSCUBE REBINNED PROJECTED FRAME CUBE CUBE CUBE CALIBRATION PRODUCTS similar to B. Ali’s talk CALIBRATION PRODUCTS similar to B. Ali’s talk

Level 2 Spectral Cubes 15 Level 2 Spectral Cube

PACS SPECTROMETER Pipeline uses SLICED FRAMES and CUBES The concept of slicing was introduced because of the many dimension of data in a given AOR. The slices can be processed sequentially Possible Slicing “Dimensions” 1) Calibration block needed to have a separate slice. 2) Raster Mapping (Cube every IFU pointing). 3) In Chop-Nod you have NodA and NodB for every demanded position. 4) More than one line can be observed in one AOR. 5) Might want the option of separating the up and down scans of the grating 6) In unchopped mode “On” and “Off” Possible Slicing “Dimensions” 1) Calibration block needed to have a separate slice. 2) Raster Mapping (Cube every IFU pointing). 3) In Chop-Nod you have NodA and NodB for every demanded position. 4) More than one line can be observed in one AOR. 5) Might want the option of separating the up and down scans of the grating 6) In unchopped mode “On” and “Off”

How is this accomplished in HIPE 6.0 RC2 build APPLY SLICING RULE by raster/Nod Position/LINE_ID slicedFrames = SlicedFrames(level0.fitted.getCamera (camera).product) perform Level pipeline steps perform Level pipeline steps Observational Context e. g. ( 2 x 1 raster and 2 line obs) Observational Context e. g. ( 2 x 1 raster and 2 line obs) CalBlock perform Level pipeline steps CALBLOCK REMOVED perform Level pipeline steps CALBLOCK REMOVED NODA/NODB LINE 1 and 2 slicedFrame[0] slicedFrame[1] slicedFrame[2] slicedFrame[3] slicedFrame[0] slicedFrame[1] slicedFrame[2] slicedFrame[3] LINE 1 LINE 2 ABABABAB slicedFrame[1] slicedFrame[3] slicedFrame[5] slicedFrame[7] slicedFrame[2] slicedFrame[4] slicedFrame[6] slicedFrame[8] slicedFrame[0] = cal block

Manually select given line by line ID Manually select given line by line ID convert all raster frames and nod frames into sliced cubes for that line ID convert all raster frames and nod frames into sliced cubes for that line ID Level 1-2 pipeline Level 1-2 pipeline Rebinned cubes gathered into LIST Context Rebinned cubes gathered into LIST Context SpecProject FINAL LINE Projected CUBES GRID RASTERS ONTO WCS LINE1 Line 2 repeat for line etc Make sliced rebinned cubes for for all rasters and nods for given line ID