spectral characterization of calibration lamps: stis

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Spectral Spectral Characterization of Characterization of calibration lamps: STIS calibration lamps: STIS An improved list of emission lines for STIS Calibration Enhancement Florian Kerber, ST-ECF TIPS Meeting Sept 18th, 2003

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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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Page 1: Spectral Characterization of calibration lamps: STIS

Spectral Characterization of Spectral Characterization of calibration lamps: STIS calibration lamps: STIS

An improved list of emission lines for STIS Calibration Enhancement

Florian Kerber, ST-ECF

TIPS Meeting Sept 18th, 2003

Page 2: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Outline Outline

Calibration lamps for HST spectrographs STIS Calibration Enhancement (STIS-CE) ST-ECF Lamp Project Laboratory Work Results and Outlook

Page 3: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Hollow cathode lampHollow cathode lamp

Schematic drawing

Page 4: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Pt/Ne hollow cathode lamp (IUE) 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 mA

– dimensions: 19.7 by 4.5 cm; weight: 71 (285) g

Lifetime: > 750 h or 3 - 5 years of operation on IUE Source brightness stability: ~ 5 % after 5 - 10 min Rich emission line spectrum: 115 to 310 nm Wavelengths for 585 lines; Shenstone (1939)

Page 5: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Hollow cathode lamps - HST (1990)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 nm

Space Telescope Imaging Spectrograph (STIS): 115 - 1000 nm

Page 6: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Ready for Flight / Operations ?Ready for Flight / Operations ?

Engineering– for both Pt-Ne and Pt/Cr-Ne thorough characterization of

lamps in terms of hardware performance

Science Operations– information 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

Page 7: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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HST Spectrograph OperationsHST Spectrograph Operations

National Institute of Standards and Technology – Pt-Ne lamp atlas 110 - 400 nm with ~ 3000 lines (Reader et

al., 1990, ApJS 72, 831)

Page 8: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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STIS OperationsSTIS Operations

Pt line list from NIST Cr lines can not be used because of lack of lab data 1st 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

Page 9: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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STIS Calibration EnhancementSTIS Calibration Enhancement

Physical Model of STIS– Spectrograph Model

Laboratory Standards– Good line list is required to realize full potential of

physical model

Page 10: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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ST-ECF Lamp Project ST-ECF Lamp Project

Dedicated ESA funding Measure spectrum of Pt/Cr-Ne lamp at NIST: 110 -

320 nm Derive an accurate ( < 1/1000 nm) list of wavelengths

as input for STIS-CE Quantify differences between Pt-Ne and Pt/Cr-Ne

spectrum Look into aging effects of hollow cathode lamps

Page 11: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Status of the ST-ECF Lamp Project Status of the ST-ECF Lamp Project

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

Page 12: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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NIST Eagle vacuum spectrographNIST Eagle vacuum spectrograph

10.7 m focal length, Vacuum UV (VUV) coverage– 1.25 m/1 m diameter

– 13 m long, 15 m3

– 3 chambers

Two 16 in. UV sensitive photographic plates– 750 Å coverage

– 0.78 Å/mm resolution

Page 13: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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NIST Eagle vacuum spectrographNIST Eagle vacuum spectrograph

Page 14: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Synchrotron UV Facility (SURF III)Synchrotron UV Facility (SURF III)

Fourier Transform Spectrograph (FTS 700)

Page 15: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Hollow cathode lampHollow cathode lamp

Page 16: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Measure spectrum of Pt/Cr-Ne lamp at NIST– 10.7 m vacuum spectrograph: 113 - 183 nm

– FTS: 165 - 350 nm

Derive an accurate ( < 1/1000 nm) list of wavelengths as input for STIS-CEs – FUV: > 1100 lines total - 95% identified; 235 Cr

– NUV: > 3500 lines; ca 50% Cr

ST-ECF Lamp Project - Status ST-ECF Lamp Project - Status

in progress

Page 17: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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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 current

Aging of lamps– accelerated aging test: 30s on/30s off cycle

– vintage flight hardware

ST-ECF Lamp Project - Status ST-ECF Lamp Project - Status

1000 h without significant change

in progress

FOS & GHRS lamps

Page 18: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Mystery feature “Clump” ~1430 Mystery feature “Clump” ~1430 ÅÅ

Seen in both in FOS and STIS

Page 19: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Chromium “Clump” ~1430 Chromium “Clump” ~1430 ÅÅ

Pt/Cr-Ne

Cr-Ne

Pt-Ne

Page 20: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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FUV Spectra: Pt vs CrFUV Spectra: Pt vs Cr

Faint Pt-Ne: oldNew CrPt-Ne: old & new

Page 21: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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NUV Spectra: Pt vs CrNUV Spectra: Pt vs Cr

Pt/Cr-Ne

Cr-Ne

Pt-Ne

Page 22: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Input for STIS-CE Input for STIS-CE

NUV c: 2843 Å Lines seen : ~ 450 Pt: ~ 100 lines Cr: ~ 700 lines

known

Page 23: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Open Instrument SurgeryOpen Instrument Surgery

Page 24: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Veteran Space LampsVeteran Space Lamps

After seven years of operation in space back to the lab ...

FOS GHRS

they still work perfectly fine

Page 25: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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ST-ECF Lamp Project: Future ST-ECF Lamp Project: Future

NUV FTS data reduction, fall 2003 Return of FOS lamps to museum, Sept 23rd Paper I, ApJS, Sept 2003 (FUV results)

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

Page 26: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Lessons learned: Calibration ...Lessons learned: Calibration ...

requires attention to detail …

needs to be an integral part of any science project

requires expertise from different fields

is at the heart of scientific understanding

will give you better results

Page 27: Spectral Characterization of calibration lamps: STIS

TIPS Sept 18th, 2003

F. Kerber, ST-ECF

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Lessons learned ... Lessons learned ...