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Submillimeter space missions : History and prospects

Submillimeter space missions : History and prospects. Frank Helmich – Principal Investigator for Herschel-HIFI. Cryocooler analysis OD#90-1249 (T101/102). The search for the oldest reference to C+. Table 3 from the 1968 paper. Overview – only concentrating on satellites !.

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Submillimeter space missions : History and prospects

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  1. Submillimeter spacemissions: History and prospects Frank Helmich – PrincipalInvestigatorforHerschel-HIFI

  2. Cryocooler analysis OD#90-1249 (T101/102)

  3. The search for the oldestreference to C+

  4. Table 3 from the 1968 paper

  5. Overview – onlyconcentratingonsatellites! • COBE-FIRAS • ISO-LWS • Herschel • PACS • SPIRE • HIFI • Improvements in data • Future • Millimetron-HFI • SPICA-SAFARI • [CII] mapper: • HIGAL follow-up / GAIA follow-up

  6. COBE-FIRAS • Fixsen et al. 1999

  7. InfraredSpaceObservatory – Long Wavelength Spectrometer (ISO-LWS)

  8. M82 & Arp 220 by LWS Colbert et al 1999 Gonzalez-Alfonso et al 2004

  9. C+ in Sgr B2 Goicoechea et al 2004 Polehampton et al 2007 LWS-FP scan

  10. HerschelSpaceObservatory: launch 14 May 2009

  11. M82 – spatiallyresolvedspectrallineimages Subaru Thanks to EckhardSturm! Contursi + 2013 (SHINING)

  12. M82 – spatiallyresolvedkinematics Velocitydispersion Contursi + 2013 (SHINING)

  13. M82 - spatiallyresolved PDR modellingandlinedeficitstudies in disk, centralstarburst, and in the wind Malhotra et al. 2000 Contursi + 2013 (SHINING)

  14. SPIRE : Spectrometer Beam splitter • Mach-Zehnder configuration FTS • 2 arrays of spider-web bolometers • Entire wavelength range covered simultaneously (194-671 microns) • Circular 2.6 arcmin field of view on sky • Line and continuum detection Light fromTelescope Chris Pearson : First Results from Herschel SPIRE

  15. SPIRE FTS spectrum of SMM J2135 (z=2.3) Ivison et al 2010 SPIRE is not made for the C+ frequency!

  16. ID81: high-z galaxy I. Valchanov, GT1 follow up of H-ATLAS galaxies Detection of the redshifted C+ and O++ lines SPIRE Photometer measurements [OIII] 88.4 µm [CII] 157.7 µm Valtchanovet al., MNRAS, 2011, 415, 3473

  17. Heterodyne Instrument for the Far-Infrared

  18. Tracing clouds all over the galaxy with [CII] Click to edit Master text styles Second level Third level Fourth level Fifth level Langer et al 2010 18

  19. HEB Matching Technique • HEB bands (6 and 7) suffer from impedance mismatch between mixer and amplifier  electrical standing waves in IF • Induces non-sinusoidal baseline ripple • Difficult to remove using fitHifiFringe

  20. HEB Matching Technique • New approach as of HCSS 9: matching techniqueHEBStWvCatalogCorrection.py (in HIFI ICC build) • Idea: characterize standing waves from OFF observations,then subtract from ON data • Need catalog of OFF data to capture all SW patterns • “Long” obs usually have enough OFF to “self-calibrate” • “Short” obs require a catalog

  21. HEB Matching Technique

  22. HEB Matching Technique • New approach as of HCSS 9: matching techniqueHEBStWvCatalogCorrection.py (in HIFI ICC build) • Idea: characterize standing waves from OFF observations,then subtract from ON data • Need catalog of OFF data to capture all SW patterns • “Long” obs usually have enough OFF to “self-calibrate” • “Short” obs require a catalog • HIFI actions: • Generate catalogs from public data (stability observations) • Make script usable for AOTs other than DBS • Turn into plugin to divorce it from HIPE release cycles • Make script robust enough for non-interactive use (?)

  23. Herschellegacyon C+ • Of order 50% of the HIFI time was dedicated to [CII] observations – thousands of hours • These data do sufferfromelectrical standing waves • Methods to cureit are releasednow, and the ICC will continue to improve the level 2 data • Thisarchive (HSA) is equivalent to at leasttens of dedicated SOFIA flights • PACS alwaysdelivers a small map (5x5 pixels) – calibration is stillimproving

  24. Millimetron mission • Approved mission of Russian Space Agency with approved funding • Led byAstro Space Center, PI N. Kardashov (Radioastron) • Launch date 2019…2022 (as early as possible) • Life time 10 years (5 Cold) • Orbit – Lagrangian L2 • Mirror • 10 m deployable, <2 THz (>150 micron) • 3m central part, <6 THz (>50 micron) • Actively cooled to 30K (considering 4K for central part) • Closed cycle mechanical coolers, 4K instrumentation package • In Russia • Launch, Proton-M • Satellite • Deployable antenna • Large mission, 4000 kg, 5000 W • Instrumentation is built by international consortium • Heterodyne arrays HIFI+ (CII, O, OH etc) • Imaging spectrometer <150 micron (similar SPICA BLISS) • Imaging spectrometer FTS (3mm – 0.3mm) • S-VLBI channels (some ALMA bands + VLBI) Can be launchedbefore JWST, SPICA ADD THE SLIDE TITLE BY HAND or COPY

  25. The SPICA mission • The first big cold mirror in space • Jaxa-led, with European contributions: • ESA: 3.2m monolithic mirror, < 6 K • SAFARI instrument – PI from SRON • ESA ground segment contribution • European science center • Note: much Herschel experience brought in - HW and science • Instruments covering 5- 210 μm • MIR imaging spectro-photometer • MIR coronagraph • Focal Plane Camera (science chnl) • SAFARI FIR imaging spectrometer SPICA and SAFARI - the next step after Herschel

  26. The Mach-Zehnder interferometer RS(σ,p) S(σ) RS(σ) R2 S(σ) +T2 S(σ) {1+cos(2pσ)} 2RT S(σ) {1+cos(2pσ)} TS(σ) The SAFARI imaging spectrometer - Italian SPICA workshop

  27. The SAFARI optics – from entrance to detector • Mach-Zehnder interferometer • Two symmetrical sets of FTS ports • Input port 1  sky • Input port 2  calibrator • Output port 1  LW band • Output Port 2  MW/SW bands POM From Telescope The SAFARI imaging spectrometer - Italian SPICA workshop

  28. Reference design - SAFARI Focal Plane Unit Input Optics Module with Pick-off-Mirror Detector filters - SW Filter wheel FTSM 4K-shield around detector box and FPA’s Focal Plane Assembly Mach-Zehnder interferometer 50mK cooler Detector filters – LW/MW The SAFARI imaging spectrometer - Italian SPICA workshop

  29. SAFARI FPU mechanisms Shutter Calibration source Filter wheel FTSM FTSM 50mK cooler The SAFARI imaging spectrometer - Italian SPICA workshop

  30. Detector system - Focal Plane Assemblies • Unit to hold TES’s + LC filters + SQUID’s • One FPA per detector array • Isolate temperature levels: 50mK/300mK/1.7K • Shielding: quasi-static B-fields, radiated EMI, stray light • Challenges • Multiple functions ⤄ volume/mass constraints • High launch loads • Compact, light-weight B-shield • Harness for upto ~2000 pixels The SAFARI imaging spectrometer - Italian SPICA workshop

  31. SAFARI sensitivity – goal is within reach • Requirement on detector sensitivity • NEP 2x10-19 W/Hz (x √2 in SW array) • Requirement → total system NEP increased by √1.5x • Requirement on instrument saturation power • Observe 1 Jy point source without a neutral density filter • ND filter (in filter wheel) required for stronger sources • System NEP contributors • Detector (dark) NEP • Sky background - dominates for SW/MW • Zodi, CIRB, CMB • Satellite background - significant for LW • 14.4 K baffle (10-4 coupling), 6 K telescope, 4.75 K instrument cavity • Instrument efficiencies • Total detector efficiency = 64% • Instrument = 17% • FTS, filters, dicroic etc. • Detector sky sampling • LW/MW Nyquist, SW sub-Nyquist The SAFARI imaging spectrometer - Italian SPICA workshop

  32. SAFARI Key Scientific Drivers • Characterising 1000s of obscured galaxies through spectroscopy • Disentangling the interplay between star-formation and black holes in galaxy evolution • Understanding the Oxygen/Water chemistry of proto-planetary disks – “planet formation regions” • Observing water ice to understand the role of the “snow line” in planetary formation • Characterising 100s of objects in our own “debris disk”  Ultra-sensitive (cold telescope!) far infrared (34-210 μm) observations are essential for any of these. Note: the SAFARI science case is fully described in the SPICA Yellow Book SPICA and SAFARI - the next step after Herschel

  33. SAFARI: high speed imaging spectroscopy Spectroscopy for all SPIRE background sources • SAFARI FTS will take spectra of 7-10 sources per field •  ~1000 hrs for 1°x1° at few 10-19 Wm-2 SPICA and SAFARI - the next step after Herschel

  34. Spectroscopic surveys – high throughput • For blind spectroscopic surveys with SAFARI detection of large numbers of galaxies is predicted: • 0.5 square degrees, ~500 hrs observing time, σ ~ few×10-19 Wm-2; 5σdetection limit • Different galaxy evolution models • all models predict 4000or more objects detected in 4 lines Just one such survey gives a massive database! ~ 1 degree AGN PDRHII region SPICA and SAFARI - the next step after Herschel

  35. GOT C+ [CII] 1.9 THz Survey 11 LOS 11 LOS 10 LOS 11 LOS 7 LOS 6 LOS 7 LOS 6 LOS Galactic Plane Survey - systematic volume weighted sample of ≈500 LOSs in the disk • Concentrated towards inner Galaxy • Sampled lat b = 0o, +/- 0.5o & 1o Galactic Central Region: CII strip maps sampling ≈300 positions in On The Fly (OTF) mapping mode.

  36. GOT C+ [CII] Distribution in the Milky Way Spiral arm tangents Pineda et al. (2013) submitted

  37. Hi-GalA Herschel Key-Project to map the Galactic Plane in the Far-IR Simultaneous 5-bands (70-160-250-350-500mm) continuum mapping of 720 sq. deg. of the Galactic Plane (|b|≤1°) With almost 900 hours observing time is the largest OPEN TIME Herschel KP Galaxy-wide Census, Luminosity, Mass and SED of dust structures at all scales from massive YSOs to Spiral Arms

  38. HiGalsurvey

  39. Herschel 70-160-350mm composite Traficante et al. 2012 3D decomposition of dust emission is based on the assumption that dust is associated to the atomic, molecular and ionised gas phases.Along any given line of sight, the dust emission can be therefore correlated to specific tracers of the gas: HI 21cm, CO, Radio Recombination Lines l=30° Dust in Scutum-Crux ring Solving the equation yields the basic parameters of the dust mixture associated to each gas phase Pretty cool…….however…..

  40. Traficante et al. 2012 … in rings 2 and 3 (orange and violet), the iterative inversion of the equation provides low correlation coefficients between the emission of dust, and the three gas tracers used, or even anti-correlation……why is that ? The most likely explanation is that there is a gas component that is not traced by any of the three gas tracers used. Grenier (2005) suggested this from g-ray data and called it “dark gas” and Planck (2012) also confirmed it at lower angular scales than Herschel. Is this “dark gas” an untraceable mixture of HI-H2 ? Or is it rather the PDR-like gas that is traced in the “Got C+” Herschel CII observations ? Statistics is the key requirement to confirm this and to finally unveil the complete budget of the gas in the Milky Way. The cross-analysis of Herschel Hi-GAL maps with unbiased CII survey data (not pencil-beam) could be the ultimate tool to accomplish this.

  41. [CII mapper] - GAIA/EUCLID • What is causing the extinction to the stars that GAIA willmeasure? • What are the foregroundsthat EUCLID willsee? • Is informationfromPlancksufficient? Planck conference early April willtell • Go beyond the Gal. Plane? ESA/Planckcollaboration

  42. Technicalheritagefor [CII] mapper: Planck • Planckheritage Picturescourtesy of ESA

  43. Technicalheritagefor [CII] mapper: Planck Coolingtechnologyexists

  44. [CII] mappertechnicalheritage: HIFI/GREAT • HEB mixers have been proven in HIFI & GREAT • LO systems are availablebasedon HIFI , GREAT and GUSSTO developments • Arraytechnology has been pioneered in ground-based programs and in the variousRadioNet programmes

  45. Highlight of HEB mixer development • Record low heterodyne sensitivity at super-THz • Allan-variance time (>30 sec) by stabilizing the LO amplitude (FIR laser, a breakthrough) W. Zhang et al, Appl. Phys. Lett. 2010. D. Hayton et al, Appl. Phys. Lett. 2012

  46. Problem areas • Backends –FFTS are wonderfulbut power consuming • Data rate – Largearrayswithlarge IF: high rate • Toomany IF amplifiers in the focalplane • Sensitivity

  47. Sensitivity • Use 256 pixels with T(SSB)=1000K, 0.63 km/s channels and 2 yearmission • T_noise = 0.18K rms, out of planeaveragingcan (and probably must) bedone • Less mixers immediatelyresult in lowersensitivity • Longermissionleads to bettersensitivity • Scan ratewouldbe (averaged) 2.7 degrees/second

  48. Optimizingfor the GalacticPlane? • Opticscouldbechangedsuchthat we look closer to the ecliptic and thusavoidmeasuringmuch of blank sky • However, GalacticPlane and ecliptic are tilted 60 degrees • How to keep following the Plane over (part of) the missionlifetime? • Is there a need to oversize the solar panels? • Etc. etc. -> orbit studies needed • Shouldtherealsobe [NII], [OI] and [OIII] channels? (withmuchless pixels)

  49. Conclusion • UseHerschel data • Use SOFIA • If GUSSTO, Millimetron and SPICA are all approvedmuch more data willcome in • [CII] mapper is almosttechnologicallyfeasible, butnotsimple

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