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LISA spectrograph Long slit Intermediate resolution Spectrograph for Astronomy

LISA spectrograph Long slit Intermediate resolution Spectrograph for Astronomy Performances and application. Christian Buil. Active Spectroscopy in Astronomy Essen – 7 May 2011. Spectrograph resolution categories ( R = l/dl ). Lhires R = 16000. eShel R = 11000. High resolution.

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LISA spectrograph Long slit Intermediate resolution Spectrograph for Astronomy

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  1. LISA spectrograph Long slit Intermediate resolution Spectrograph for Astronomy Performances and application Christian Buil Active Spectroscopy in Astronomy Essen – 7 May 2011

  2. Spectrograph resolution categories ( R = l/dl ) Lhires R = 16000 eShel R = 11000 High resolution Medium resolution (or intermediate) LISA R = 500 to 1000 Star Analyser R = 100 to 200 Low resolution

  3. Spectral resolution (R) and luminosity (L) : a complementary effort R x L = constant Faint object spectroscopy The example of Star Analyser : very low resolution, very high luminosity Planetary nebulae NGC 2392 – 15 x 30 seconds

  4. Faint object spectroscopy But do not mystake luminosity and detectivity ! One limitation of slitless spectroscopy : sky background pollution The symbiotic star V1016 Cyg Another limitation of SA : optical aberration Chromatic coma : a source of detectivity degradation (bad capacity to concentrate energy) Grism improvement

  5. Faint object spectroscopy The importance of an entrance slit Large slit Narrow slit The sky background level if proportionnal to the slit wide The backgroung photon noise is proportionnal to the square root of slit wide

  6. The LISA concept (1/2) • Ajustable entrance slit by step (from 15 microns to 100 microns) • (capacity to optimise spectral resolution to a specifictarget) • Fast input beam : up to f/5 input i.e. highluminosityspectrograph (reducepotential guidance problembecauseshorter focal length, capture of faint surface objet like galaxies, comets, … • Optimized spectral dispersion to modern camera (2 A / pixel sampling on a popular KAF8300 CCD ship) • Balance between power resolutioncapacity and scientificinterest (R = 500 to 1000 typically) – Sodium doublet isjustseparatedwith a 23 microns slit 2D spectrum of moon surface Na DA, D2 Mg I,2,3 Halpha

  7. The LISA concept (2/2) • Wide spectral range in one shot : 3950 A – 7200 A (+ IR option) • Integrated calibration system (neonlamp + tungstenlamp) : easy to use and standard pipeline processing. Possibility to fullyautomatize acquisition. • Compact and moderateweigth : adaptable on smallrefractor and refractor. • Lowcost : large diffusion if possible!

  8. Optical design Internal grandissement G = 0,603 For example: if the telescope focal / diameter ratio is 6, the final F/D is 6 x 0,603 = 3,6 (LISA is equivalent to a focal reducer).

  9. Mechanical design

  10. Mechanical design Ajustable grating angle Calibration unit

  11. Pointing and guidance system High quality slit image on the guidance camera (here M104 galaxy with a Watec 120N) High reflectivity slit Very constant edge

  12. LISA on a Celestron 11 telescope

  13. Calibration module (spectral calibration and flat-field) Electromagnetic system – 12 V power – Remote operation possible

  14. Interfaces Optimal input focal ratio f/5 to f/7 A fast Newton telescope is ideal (achromatism) For SC Telescope : focal reducer (here a Baader Alan Gee - final ratio f/6.8) Fast adaptation for CCD camera and DSRL

  15. Example of setup with Atik CCD cameras Atik 314L for spectra acquistion (1390 x 1040 x 6.45 µm pixel size)Readout noise : 4.5 e-, Camera gain : 0.250 e-/ADU, typical quantum efficiency @ 656 nm : 55% Atik Titan for pointing and guiding functions (faint object identification capability + rudimentary photometry measure on the targets) Low cost solution for LISA, low mass on the telescope, high performances

  16. Amovible entrance slit High precision chromium serigraphy 15 – 19 – 23 – 32 microns (option 50 – 75 – 100 microns + 19 microns hole) Slit 23 microns – R = 1100 W = 2,5 arcsec on C11 f/6.8 Slit 50 microns – R = 600 W = 5.4 arcsec on C11 f/6.8

  17. Automatised processing Rlhires application

  18. Automatic spectral calibration by using observed type A, B or G star spectra and internal neon lamp spectrum Fit dispersion law with a 3e order polynomial function (typical RMS error : 0.3 to 0.4 A)

  19. Many tools available : computation of heliocentric velocity, H2O removal, atmopsheric transmission, spectra database, …. French/english interface

  20. Limit magnitude Integration time : 1 hour (6 x 600 sec)Signal to noise ratio = 10 (@ Halpha)Type A0V star – Seeing = 3 arcsec CCD KAF-8300 (Binning 1 x1) Altitude 0 m - Suburban Altitude 3000 m – Dark sky

  21. Limit magnitude (function of detector type) Integration time : 1 hour (6 x 600 sec)Signal to noise ratio = 10 (@ Halpha)Type A0V star – Seeing = 3 arcsec Altitude 3000 m – Dark sky CCD KAF-8300 (Binning 2 x2) CCD KAF-3200 (Binning 2 x2) CCD ICX285AL (Binning 2 x2) M = 16.1 (KAF-8300) M = 16.5 (KAF-3200)M = 16.6 (ICX424AL) 3 hours integration (18 x 600 sec) – Slit 50 µm – D = 28 cm F/D = 6.8

  22. Observation with LISA spectrograph

  23. Typical aspect of LISA 2D spectra Symbiotic star V1016 Cyg Star Analyser 2D spectrum before sky removal (23 µm slit) 2D spectrum after sky substraction

  24. Symbiotic star V1016 Cyg (V = 11.2) : lines identification

  25. First step : observation of normal stars (1/2)

  26. First step : observation of normal stars (2/2)

  27. Survey of know Be Star + and detection of new Be star Beta Lyrae (Shelyak) – 15 x 30 s Rapid scan of B and A star for Halpha emission signature (5-10 minutes exposure) (list of nearly 1000 stars – magnitude < 10)

  28. Faint Be stars observation (BeSS) V = 6.09 – 9 x 120 s V = 4.74 – 8 x 60 s V = 8.62 – 6 x 300 s (new BeSS entry) V = 8.63 – 7 x 300 s (new BeSS entry)

  29. Survey of cataclysmic (novae like) SS Cyg outburst (V = 8.7) – April 4.1, 2011

  30. List of cataclysmic star (François Teyssier) …

  31. Outburst of cataclysmic V694 Mon High velocity wind – Fast evolution

  32. V694 Mon – Visible + IR capacity of LISA spectrograph

  33. Recurent nova T Pyxidis : day to day monitoring of profile evolution

  34. Observation at very low angular elevation : associated problem T Pyxidis declinaison = -32 degrees T Pyxidis 2D spectrum 6 arcsec refraction at 12 degree elevation Paralactic angle Horizon

  35. Nova Sagittarii 2011 #2 (V5588 Sgr) V = 13.2

  36. Eruption of Herbig Ae/Be star Z CMa Vis + IR spectrum Detail of IR spectrum

  37. MIRA star R Leo at V = 8.5 Wide band spectrum

  38. Wolf-Rayet star HD 56925 WR 7 – V = 11.7 HD 56925 in NGC 2359 nebula

  39. Messier 1 (Crab nebulae) - 5 x 600 s @ R = 600 R Mon in NGC 2261 nebula 3 x 600 s @ R = 1000

  40. SUPERNOVA SN 2011ae in MCG-3-30-19

  41. SUPERNOVA SN 2011by in NGC 3979

  42. Messier 104 Sombrero galaxy Audela autoguiding 2D spectrum Na rest = 5892.9 A - Na observed = 5916.9 A – z = (5916.9 – 5892.9) / 5892.9 = 0.0041 (17 Mpc)

  43. Active galaxies (Seyfert) NGC 4151 NGC 4051

  44. Quasar 3C273 LISA infrared version Observed Halpha at 7584 A z = (7584 - 6563)/6563 = 0.155 (official z = 0.158) McDonald 2,1 m K. Thompson AJ, 395, 404,417, 1992

  45. Quasar Mrk 205 observation (V = 15.5)

  46. Quasar Mrk 205 7 x 600 sec. – 50 µm slit Observed z = 0.0710 (official value z = 0.0705)

  47. Thank you

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