Experimental Astronomy

, Volume 31, Issue 2–3, pp 131–156 | Cite as

Understanding the behaviour of X-shooter via the application of a physical model

I. Quality control
  • Paul David Bristow
  • Joël Vernet
  • Sabine Moehler
  • Andrea Modigliani
  • Florian Kerber
  • Michael R. Rosa
Original Article
First Online:
Received:
Accepted:

Abstract

We show how traditional instrument quality control trending can be augmented by the use of a physical instrument model. The ESO VLT archive contains a detailed record of instrument diagnostics and calibration parameters while ESO quality control monitors changes in critical parameters. The physical model allows changes in positions, orientations and other physical properties of a spectrograph to be determined from standard wavelength calibration exposures via an optimisation process that seeks the physical model parameters that best reproduce the calibration features in the data. We introduce physical model parameters to the quality control monitoring. When applying this technique to archived calibration exposures, we find that the results are sensitive to the combination of parameters open to the optimisation process. Therefore we determine the most favourable set of physical parameters to optimise for each arm. We then show correlations between several physical parameters and instrument temperature sensor readings and epoch. In addition we find clear discontinuities in some physical parameter values that correspond to known maintenance events.

Keywords

VLT Physical modelling Ray tracing X-shooter Quality control Calibration Physical interpretation 
This is a preview of subscription content, log in to check access.

Notes

Acknowledgements

We wish to thank the many members of the X-shooter consortium who have helped with the development of the physical model and its integration into the DRS pipeline software, in particular Paolo Goldoni, Frèdèric Royer and Règis Haigron. The manuscript undoubtedly benefitted in terms of clarity and accuracy thanks to the referee’s detailed report.

References

  1. 1.
    Ballester, P., Rosa, M.R.: Modeling echelle spectrographs. Astron. Astrophys. Suppl. Ser. 126(3), 563–571 (1997)ADSCrossRefGoogle Scholar
  2. 2.
    Ballester, P., Modigliani, A., Boitquin, O., Cristiani, S., Hanuschik, R., Kaufer, A., Wolf, S.: The UVES data reduction pipeline. Messenger 101, 31–36 (2000)ADSGoogle Scholar
  3. 3.
    Bristow, P.: Model Based Wavelength Calibration for CRIRES, vol. 6270. SPIE, 62701T (2006)Google Scholar
  4. 4.
    Bristow, P., Kerber, F.: Selection of Wavelength Calibration Features for Automatic Format Recovery in Astronomical Spectrographs, vol. 7014. SPIE, 70145V (2008)Google Scholar
  5. 5.
    Bristow, P., Kerber, F., Rosa, M.R.: Advanced calibration techniques for astronomical spectrographs. Messenger 131, 2–6. URL http://esoads.eso.org/abs/2008Msngr.131....2B (2008)Google Scholar
  6. 6.
    Bristow, P., Kerber, F., Rosa, M.R., Vernet, J., Goldoni, P., Spano, P., Modigliani, A.: X-Shooter Physical Model, vol. 7014. SPIE, 70143X (2008)Google Scholar
  7. 7.
    Bristow, P., Vernet, J., Modigliani, A., Moehler, S., Kerber, F.: Undestanding X-shooter Flexure via the Application of a Physical Model (2011, in preparation)Google Scholar
  8. 8.
    Carter, E.: Simulated Annealing Information. http://www.taygeta.com/annealing/simanneal.html (2001)
  9. 9.
    D’Odorico, S.: X-Shooter UV- to K-Band Intermediate-Resolution High-Efficiency Spectrograph for the VLT: Status Report at the Final Design Review, vol. 6269. SPIE, 626933 (2006)Google Scholar
  10. 10.
    Kerber, F., Bristow, P., Rosa, M.R.: STIS Calibration Enhancement (STIS-CE): Dispersion Solutions Based on a Physical Instrument Model. The 2005 HST Calibration Workshop: Hubble After the Transition to Two-Gyro Mode, 309 (2006)Google Scholar
  11. 11.
    Kerber, F., Nave, G., Sansonetti, C.J.: The spectrum of Th–Ar hollow cathode lamps in the 691–5804 nm region: establishing wavelength standards for the calibration of infrared spectrographs. Astrophys. J. Suppl. Ser. 178(2), 374–381 (2008)ADSCrossRefGoogle Scholar
  12. 12.
    Kirkpatrick, S., Gelatt, C.D., Vecchi, M.P.: Optimization by simulated annealing. Science (New York, NY) 220(4598), 671–680 (1983)MathSciNetADSCrossRefMATHGoogle Scholar
  13. 13.
    Modigliani, A., et al.: The X-Shooter Pipeline, vol. 7737. SPIE, 773728 (2010)Google Scholar
  14. 14.
    Moehler, S., Bristow, P., Kerber, F., Modigliani, A., Vernet, J.: The Physical Model in Action: Quality Control for X-Shooter, vol. 7737. SPIE, 773756 (2010)Google Scholar
  15. 15.
    Palmer, B.A., Engleman, R.: Atlas of the Thorium Spectrum. National Laboratory, Los Alamos (1983)Google Scholar
  16. 16.
    Press, W.H., Flannery, B.P., Teukolsky, S.A., Vetterling, W.T.: Numerical Recipes in C. The Art of Scientific Computing. University Press, Cambridge (1989)Google Scholar
  17. 17.
    Reader, J., Kramida, A.E., Ralchenko, Y.: Atomic Spectroscopic Databases at NIST. In: Proc. NASA LAW 2006, vol. 239 (2006)Google Scholar
  18. 18.
    Spano, P.: The Optical Design of the X-Shooter for the VLT, vol. 6269. SPIE, 62692X (2006)Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Paul David Bristow
    • 1
  • Joël Vernet
    • 1
  • Sabine Moehler
    • 1
  • Andrea Modigliani
    • 1
  • Florian Kerber
    • 1
  • Michael R. Rosa
    • 2
  1. 1.ESOGarching bei MünchenGermany
  2. 2.Space Telescope European Co-ordinating FacilityGarching bei MünchenGermany

Personalised recommendations