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Spectral Characterization of calibration lamps: STIS. An improved list of emission lines for STIS Calibration Enhancement Florian Kerber, ST-ECF TIPS Meeting Sept 18th, 2003. Outline. Calibration lamps for HST spectrographs STIS Calibration Enhancement (STIS-CE) ST-ECF Lamp Project - PowerPoint PPT Presentation

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  • Spectral Characterization of calibration lamps: STIS An improved list of emission lines for STIS Calibration Enhancement

    Florian Kerber, ST-ECFTIPS Meeting Sept 18th, 2003

    F. Kerber, ST-ECF

  • Outline Calibration lamps for HST spectrographs STIS Calibration Enhancement (STIS-CE)ST-ECF Lamp ProjectLaboratory WorkResults and Outlook

    F. Kerber, ST-ECF

  • Hollow cathode lampSchematic drawing

    F. Kerber, ST-ECF

  • Pt/Ne hollow cathode lamp (IUE) Parameters of operation starting voltage: 300 V; operating voltage: 185 V; current: 10 - 60 mA, power consumption: 2 W @ 10 mAdimensions: 19.7 by 4.5 cm; weight: 71 (285) gLifetime: > 750 h or 3 - 5 years of operation on IUESource brightness stability: ~ 5 % after 5 - 10 minRich emission line spectrum: 115 to 310 nm Wavelengths for 585 lines; Shenstone (1939)

    F. Kerber, ST-ECF

  • Hollow cathode lamps - HST (1990)Goddard High Resolution Spectrograph (GHRS): 115 - 320 nm; Pt-Ne ok

    Faint Object Spectrograph (FOS): 115 - 895 nm Addition of ~ 10% Cr to cathode extends coverage to 540 nm and Ne has lines up to 800 nmSpace Telescope Imaging Spectrograph (STIS): 115 - 1000 nm

    F. Kerber, ST-ECF

  • Ready for Flight / Operations ?Engineeringfor both Pt-Ne and Pt/Cr-Ne thorough characterization of lamps in terms of hardware performanceScience Operationsinformation on spectral output incomplete and crucial wavelength information based on measurements done in the 1930s (Pt) or absent (Cr)

    no spectral characterization of flight hardware

    F. Kerber, ST-ECF

  • HST Spectrograph OperationsNational Institute of Standards and Technology Pt-Ne lamp atlas 110 - 400 nm with ~ 3000 lines (Reader et al., 1990, ApJS 72, 831)

    F. Kerber, ST-ECF

  • STIS OperationsPt line list from NISTCr lines can not be used because of lack of lab data1st order long-slit modes have many Pt/Cr blends wavelengths assigned should be average weighted by line intensity ratios, which are not known Empirical approach using 2-D polynomial fitsfor Echelle modes

    F. Kerber, ST-ECF

  • STIS Calibration EnhancementPhysical Model of STISSpectrograph Model

    Laboratory StandardsGood line list is required to realize full potential of physical model

    F. Kerber, ST-ECF

  • ST-ECF Lamp Project Dedicated ESA fundingMeasure spectrum of Pt/Cr-Ne lamp at NIST: 110 - 320 nmDerive an accurate ( < 1/1000 nm) list of wavelengths as input for STIS-CEQuantify differences between Pt-Ne and Pt/Cr-Ne spectrumLook into aging effects of hollow cathode lamps

    F. Kerber, ST-ECF

  • Status of the ST-ECF Lamp Project First memorandum May 2001Approved & funded in spring 2002Contracts to NIST and IST (lamps) issued June 2002 FUV: 5 week measurement campaign Sep/Oct 2002Intermediate results delivered Nov & Dec 2002NUV: 6 week campaign in Apr/May 2003Use within STIS-CE in progress

    F. Kerber, ST-ECF

  • NIST Eagle vacuum spectrograph10.7 m focal length, Vacuum UV (VUV) coverage1.25 m/1 m diameter 13 m long, 15 m3 3 chambersTwo 16 in. UV sensitive photographic plates 750 coverage 0.78 /mm resolution

    F. Kerber, ST-ECF

  • NIST Eagle vacuum spectrograph

  • Synchrotron UV Facility (SURF III)Fourier Transform Spectrograph (FTS 700)

  • Hollow cathode lamp

  • ST-ECF Lamp Project - Status Measure spectrum of Pt/Cr-Ne lamp at NIST10.7 m vacuum spectrograph: 113 - 183 nmFTS: 165 - 350 nm

    Derive an accurate ( < 1/1000 nm) list of wavelengths as input for STIS-CEs FUV: > 1100 lines total - 95% identified; 235 CrNUV: > 3500 lines; ca 50% Crin progress

    F. Kerber, ST-ECF

  • ST-ECF Lamp Project - Status Quantify differences between Pt-Ne and Pt/Cr-Ne spectrum addition of Cr changes of line ratios metal vs gas change as a function of operating currentAging of lampsaccelerated aging test: 30s on/30s off cycle

    vintage flight hardware1000 h without significant changein progressFOS & GHRS lamps

    F. Kerber, ST-ECF

  • Mystery feature Clump ~1430 Seen in both in FOS and STIS

    F. Kerber, ST-ECF

  • Chromium Clump ~1430 Pt/Cr-NeCr-NePt-Ne

    F. Kerber, ST-ECF

  • FUV Spectra: Pt vs CrFaint Pt-Ne: oldNew CrPt-Ne: old & new

    F. Kerber, ST-ECF

  • NUV Spectra: Pt vs CrPt/Cr-NeCr-NePt-Ne

    F. Kerber, ST-ECF

  • Input for STIS-CE NUV c: 2843 Lines seen : ~ 450Pt: ~ 100 linesCr: ~ 700 lines known

    F. Kerber, ST-ECF

  • Open Instrument Surgery

    F. Kerber, ST-ECF

  • Veteran Space LampsAfter seven years of operation in space back to the lab ...FOSGHRSthey still work perfectly fine

    F. Kerber, ST-ECF

  • ST-ECF Lamp Project: Future NUV FTS data reduction, fall 2003Return of FOS lamps to museum, Sept 23rdPaper I, ApJS, Sept 2003 (FUV results)

    STIS-CE new dispersion solutions, end 2003Incorporate into calstis pipelineSTIS calibration proposal #10031 (PI: B. Mobasher)

    F. Kerber, ST-ECF

  • Lessons learned: Calibration ...requires attention to detail needs to be an integral part of any science project requires expertise from different fieldsis at the heart of scientific understandingwill give you better results

    F. Kerber, ST-ECF

  • Lessons learned ...