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PACS Photometer PV Phase Plan

M. Nielbock: PACS PHOT PV Phase Plan. PACS Photometer PV Phase Plan. Status Report. Markus Nielbock (MPIA). 1. M. Nielbock: PACS PHOT PV Phase Plan. PACS Calibration Document (PCD, PACS-MA-GS-001) is the compendium.

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PACS Photometer PV Phase Plan

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  1. M. Nielbock: PACS PHOT PV Phase Plan PACS Photometer PV Phase Plan Status Report Markus Nielbock (MPIA) 1

  2. M. Nielbock: PACS PHOT PV Phase Plan • PACS Calibration Document (PCD, PACS-MA-GS-001) is the compendium • contains detailed description of all calibration requirements (pre and in flight) • dedicated measurement and analysis plans for each aspect (CIPs, CAPs) • serves as main reference for calibration measurement planning (CUS scripts) • currently ~125 calibration requirements defined • ground based FM-ILT as basis for definition and reference of in orbit calibration Example from FM-ILT: FOV distortion (PICC-ME-TR-006) PHOT blue detector • PV Phase Plan document (PICC-MA-PL-001) is the immediate reference for planned PV calibration measurements and AOR configurations 2

  3. M. Nielbock: PACS PHOT PV Phase Plan • PV Phase is preceded by Commissioning Phase • FPG established • final pointing accuracy reached • functionality of mechanisms and detectors verified • PV Calibration distributed across individual test blocks • ordered according to calibration topics • respects interdependencies and necessary pre-requisites • provides coarse ordering for final time line • PACS Photometer test blocks (fully defined → 345.1 hours = 14.4 days): PV Phase only • Bolometer settings and characterisation (partly Commissioning Phase), includes read-out electronics, bias, responsivity, noise estimates, etc. 97.7 h = 4.1 d • chopper angular calibration 6.0 h = 0.25 d • FOV characterisation 3.6 h = 0.2 d • spatial calibration 67.3 h = 2.8 d • photometric calibration 13.5 h = 0.6 d • AOT validation 137.1 h = 5.7 d 3

  4. M. Nielbock: PACS PHOT PV Phase Plan Test Block: Bolometer settings and characterisation (fully defined) • depends on results from Commissioning Phase (Steps I - III) • PV part separated into three individual test blocks • Step IV: probes low gain performance (bias / responsivity) 11 hours • Step V: probes high gain performance, depends on results from step IV 55 hours • Step VI: compares direct and DDCS read-out modes depends on results from step V 32 hours • complicates scheduling according to suggested PV time line • redistribution of ODs among instruments might be necessary • sources: dark sky field, bright flux calibrators 4

  5. M. Nielbock: PACS PHOT PV Phase Plan Test Block: Verification of chopper angular calibration (fully defined) 6 hours • verification of on-ground angular calibration and spatial scale • important for PHOT and SPEC • blue PHOT used for observations: • chopped measurements of double point sources with chop throw close to separation • sources: double stars, double galaxies, asteroid encounters (PACS-ME-TN-035) 2MASS Ks + IRAS/HIRES 60 μm 2MASS Ks + MIPS 70 μm 5

  6. M. Nielbock: PACS PHOT PV Phase Plan Test Block: FOV characterisation (fully defined) 3.6 hours • assess the impact of straylight from and into the internal calibration sources • optimise positioning of chopper on internal calibration sources • accomplished by various full FOV scans with chopper • one FOV scan with CS switched off (requires modified set-up procedure) • on dark sky field (~ 1 MJy/sr @ 100 μm) to minimise external contamination IRAS 100 μm DSS 6

  7. M. Nielbock: PACS PHOT PV Phase Plan Test Block: Spatial calibration (fully defined) 67.3 hours • FOV distortion • maps of bright sources at various chopper positions measured PSF blue detector • sources: bright isolated FIR sources FM-ILT • PSF characterisation • different observing modes • investigate scanning effect on PSF shape • sources: PSF standards with blue and red SEDs (stars, blazars, asteroids) to evaluate the influence of filter bandpass on PSF size 7

  8. M. Nielbock: PACS PHOT PV Phase Plan Test Block: Spatial calibration (fully defined) 67.3 hours • straylight from celestial sources • scan maps around very bright source • sources: preferentially planets (barely visible during foreseen PV period) isolated bright FIR sources (currently: IK Tau, 319 Jy @ 60 μm) • also covers additional evaluation of electronic crosstalk and optical ghosts • scan maps of bright sources at varying chopper positions and scanning speeds 8

  9. M. Nielbock: PACS PHOT PV Phase Plan Test Block: Photometric calibration (fully defined) 13.5 hours • complements optimisation of detector settings and frequent calibration on internal CSs • provides the photometric characterisation (e.g. linearity) and absolute flux calibration • standard point-source photometry (high and low gain) • sources: 8 prime fiducial stars, 55 asteroids , planets, 7 faint flux calibrators from: Gordon et al. (2007), MIPS 70 μm calibrators 9

  10. Flux ratio model: CS2 vs. telescope incl. stray light M. Nielbock: PACS PHOT PV Phase Plan Test Block: Photometric calibration (fully defined) 13.5 hours • determines full system flat-field for blue, green, and red filters • standard scan map on bright flux standard star • issue to be traced carefully during telescope cool down: • What are the best temperatures for the two internal calibration sources? • frequent monitoring of signal ratios between CSs and changing telescope background • probably cannot be equally optimised for all filters  compromise 10

  11. M. Nielbock: PACS PHOT PV Phase Plan Test Block: AOT validation (fully defined) 137.1 hours • covered in talk by T. Müller 11

  12. M. Nielbock: PACS PHOT PV Phase Plan Calibration sources • Photometric standards prime fiducial flux calibrators (8 stars) Asteroids (55 well established,covering a large flux range) secondary flux standards (14 stars, 4 ULIRGs) faint flux standards (7 MIPS 70 μm stars from 22 mJy to 110 mJy) • PSF standards (fiducial stars, asteroids, 13 blazars) • Astrometric standards initial alignment and FOV distortion: 36 bright FIR sources (stars, galaxies, PNe) from 80 Jy to 4810 Jy @ 60 μm (PICC-ME-TN-023) pointing calibrators: 934 stars, 13 blazars, 17 QSOs and ULIRGs from 160 mJy to 187 Jy (PICC-MA-TN-003) 12

  13. M. Nielbock: PACS PHOT PV Phase Plan Calibration sources • Astrometric standards - celestial pointing star coverage (ecliptic coordinates) 13

  14. M. Nielbock: PACS PHOT PV Phase Plan Calibration sources • Astrometric standards • spatial scale calibrators (separation ≤ 4’): for field distortion and angular calibration • FIR bright double stars (16 targets) • FIR bright double galaxies (15 targets) • asteroid-asteroid encounters (5 events during PV) • asteroid-pointing star encounters (7 events during PV) • spatial scale calibrators (separation ≤ 2°): 92 pairs of pointing sources 14

  15. M. Nielbock: PACS PHOT PV Phase Plan Summary • PV calibration observations of PACS Photometer fully defined • planned PV observations provide full calibration of PACS Photometer • photometer characterisation analysis overhead might require redistribution of ODs • final settings of internal CSs after frequent monitoring of telescope background • full set of sufficiently suitable celestial calibration sources established • some scheduling problems due to visibility constraints during model PV period • AOR implementation already started (see talk by U. Klaas) 15

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