Integral Field Spectroscopy Universidad de Almeria  Viernes de Ciencia 14 January 2011 S.F.Sánchez  (CAHA)
IFS or 3D Spectroscopy <ul><li>Is the spectroscopic technique that samples a quasi-continous area in the sky (FOV). </li><...
Different kind of spaxels. <ul><li>Is the spectroscopic technique that samples a quasi-continous area in the sky (FOV). </...
How to send the light to the Spectrograph? <ul><li>Image Slicers: Light is “sliced” in small continous pseudo-slits: SINFO...
Fiber Feed IFS technique
The Raw data of FF IFUs
The Raw data of FF IFUs
FF IFU: Data Reduction (I) <ul><li>Continuum exposure used to find and trace the location of the spectra in the CCD. </li>...
FF IFU: Data Reduction (II) <ul><li>Sky-frames taken during the twilight used to correct for the differentical transmissio...
FF IFU: Data Reduction (III) <ul><li>Re-arrange the dithered pointings in a single row-stacked spectra frame, plus the com...
The Raw data of FF IFUs
Tracing process (I)
Tracing process (II)
Extraction: How to Add flux?
Extraction: cross-talk?
Extraction: The final product
Distorsions: Shifting lines.
Dispersion:Which line are you?
Fiber-to-Fiber transmission
Sky subtraction... If  possible.
Where my spectra comes from?.
PMAS/PPAK: Dithering. <ul><li>3 position dither pattern per pointing. </li></ul><ul><li>Complete spatial covering of the F...
WF-IFS Mosaics Experiment
Matching the pointings. <ul><li>The pointings overlap, in at least 11 spectra. </li></ul><ul><li>The change in transparenc...
Results: Orion (Sánchez  et al. 2006)
Results: M74 (Sánchez et al. 2010)
CALIFA: Summary I <ul><li>Calar Alto Legacy Integral Field Area survey. </li></ul><ul><li>Survey of ~600 Galaxies in the L...
CALIFA: Summary II <ul><li>Proposed by 47 researchers from 5 countries: </li></ul><ul><ul><li>PI:S.F.Sánchez. </li></ul></...
CALIFA: Science Goals <ul><li>Model the resolved stellar population in galaxies of any kind and trace the star formation h...
CALIFA: Mother Sample <ul><li>Proposal: 937 galaxies, diameter selected, at 0.005<z<0.03 from SDSS imaging survey, coverin...
CALIFA: PILOT Studies
CALIFA: Pilot Study. <ul><li>Work in process: </li></ul><ul><ul><li>Data reduced. </li></ul></ul><ul><ul><li>Integrated an...
3D Spectroscopy Summary <ul><li>IFS is a common user technique (40% of the observations done with the 3.5m at CAHA, 80% of...
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Integral field spectroscopy

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Conferencia impartida por Sebastián Sánchez en los Viernes Científicos organizada por la Facultad de Ciencias Experimentales de la Universidad de Almería el 14 de enero de 2011.

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Transcript of "Integral field spectroscopy"

  1. 1. Integral Field Spectroscopy Universidad de Almeria Viernes de Ciencia 14 January 2011 S.F.Sánchez (CAHA)
  2. 2. IFS or 3D Spectroscopy <ul><li>Is the spectroscopic technique that samples a quasi-continous area in the sky (FOV). </li></ul><ul><li>The FOV is sampled by small aperture elements named spaxels, which correspond to pixels of an image. </li></ul><ul><li>Light coming through each spaxel is transported to the entrance of an spectrograph. </li></ul><ul><li>The image/plane and focal/plane are completely decoupled: Lot of software is required to reconstruct the orginal spatial shape at each wavelength. </li></ul>
  3. 3. Different kind of spaxels. <ul><li>Is the spectroscopic technique that samples a quasi-continous area in the sky (FOV). </li></ul><ul><li>The FOV is sampled by small aperture elements named spaxels, which correspond to pixels of an image. </li></ul><ul><li>Light coming through each spaxel is transported to the entrance of an spectrograph. </li></ul><ul><li>The image/plane and focal/plane are completely decoupled: Lot of software is required to reconstruct the orginal spatial shape at each wavelength. </li></ul>
  4. 4. How to send the light to the Spectrograph? <ul><li>Image Slicers: Light is “sliced” in small continous pseudo-slits: SINFONI, MUSE... </li></ul><ul><li>Lensarrays: Continous lensarray is focused in separated apertures: SAURON, TIGER... </li></ul><ul><li>Fiber-Bundles (+lensarrays): Lights is conducted by fibers: PMAS/PPAK, VIMOS, GMOS... </li></ul>
  5. 5. Fiber Feed IFS technique
  6. 6. The Raw data of FF IFUs
  7. 7. The Raw data of FF IFUs
  8. 8. FF IFU: Data Reduction (I) <ul><li>Continuum exposure used to find and trace the location of the spectra in the CCD. </li></ul><ul><li>The FWHM of the spectra projected in the cross-dispersion axis determined. </li></ul><ul><li>Gaussian extraction performed. </li></ul><ul><li>Comparison Arc used to determine the distorsion correction and wavelength solution, latter applied to the data. </li></ul>
  9. 9. FF IFU: Data Reduction (II) <ul><li>Sky-frames taken during the twilight used to correct for the differentical transmission fiber to fiber (wavelength dependent). </li></ul><ul><li>Spectrophotometric calibration standard star exposure used to determine the flux calibration, applied to the science frames. </li></ul><ul><li>Science (331), Sky (36) and calibration spectra (15) are separated in different frames, once reduced. </li></ul><ul><li>Sky spectrum is derived for each frae (median+3sigma clipping of the 36 sky-spectra) and the subtracted to the data. </li></ul>
  10. 10. FF IFU: Data Reduction (III) <ul><li>Re-arrange the dithered pointings in a single row-stacked spectra frame, plus the complementary Position Table. </li></ul><ul><li>Mask the spectral pixel strongly affected by the vignetting. </li></ul><ul><li>Interpolate the final Mosaic into a common grid datacube of 1”/pixel. </li></ul><ul><li>When available, perform a flux recalibration based on broad-band photometry. </li></ul>
  11. 11. The Raw data of FF IFUs
  12. 12. Tracing process (I)
  13. 13. Tracing process (II)
  14. 14. Extraction: How to Add flux?
  15. 15. Extraction: cross-talk?
  16. 16. Extraction: The final product
  17. 17. Distorsions: Shifting lines.
  18. 18. Dispersion:Which line are you?
  19. 19. Fiber-to-Fiber transmission
  20. 20. Sky subtraction... If possible.
  21. 21. Where my spectra comes from?.
  22. 22. PMAS/PPAK: Dithering. <ul><li>3 position dither pattern per pointing. </li></ul><ul><li>Complete spatial covering of the FOV. </li></ul><ul><li>Increase of the spatial resolution. </li></ul><ul><li>Fully implemented in R3D. </li></ul>
  23. 23. WF-IFS Mosaics Experiment
  24. 24. Matching the pointings. <ul><li>The pointings overlap, in at least 11 spectra. </li></ul><ul><li>The change in transparency is critical </li></ul><ul><li>Accuracy of the telescope offsets is also critical. </li></ul>
  25. 25. Results: Orion (Sánchez et al. 2006)
  26. 26. Results: M74 (Sánchez et al. 2010)
  27. 27. CALIFA: Summary I <ul><li>Calar Alto Legacy Integral Field Area survey. </li></ul><ul><li>Survey of ~600 Galaxies in the Local Universe (0.0005<z<0.003), i.e., D<40Mpc. </li></ul><ul><li>IFS using [email_address] Calar Alto. </li></ul><ul><li>Mid-resolution (R~1000/2000) spectroscopic data between 3700-7000AA. </li></ul><ul><li>Covering a 90% of the size of the galaxies. </li></ul>
  28. 28. CALIFA: Summary II <ul><li>Proposed by 47 researchers from 5 countries: </li></ul><ul><ul><li>PI:S.F.Sánchez. </li></ul></ul><ul><ul><li>co-PI: R.Kennicutt & A.Gil de Paz). </li></ul></ul><ul><li>It will consume ~200 dark nights in 3 years. </li></ul><ul><li>Starting the 1 st of July 2010 (NOW!!!). </li></ul><ul><li>Already on-going: </li></ul><ul><ul><li>Runs scheduled. </li></ul></ul><ul><ul><li>~40 galaxies already observed. </li></ul></ul>
  29. 29. CALIFA: Science Goals <ul><li>Model the resolved stellar population in galaxies of any kind and trace the star formation history. </li></ul><ul><li>Determine the nature of the ionized gas and its chemical abundance gradients. </li></ul><ul><li>Determine the 2D kinematic structure of galaxies in the local Universe. </li></ul>
  30. 30. CALIFA: Mother Sample <ul><li>Proposal: 937 galaxies, diameter selected, at 0.005<z<0.03 from SDSS imaging survey, covering the full CM down to Mb<-18 mag. </li></ul><ul><li>572/937 have 2MASS data. </li></ul><ul><li>339/937 have IRAS data (24 with L FIR >10 10.5 L Sun ). </li></ul><ul><li>261/937 have FIRST data. </li></ul><ul><li>All included in NYU (n sersic , scale-length). </li></ul><ul><li>All included in the GalaxyZoo. </li></ul><ul><li>537/937 have SDSS spectra: </li></ul><ul><ul><li>162 with few or no gas. </li></ul></ul><ul><ul><li>184 AGN candidates. </li></ul></ul><ul><ul><li>277 galaxies with SF ionization. </li></ul></ul>
  31. 31. CALIFA: PILOT Studies
  32. 32. CALIFA: Pilot Study. <ul><li>Work in process: </li></ul><ul><ul><li>Data reduced. </li></ul></ul><ul><ul><li>Integrated and central spectra derived. </li></ul></ul><ul><ul><li>Automatic analysis on the Integrated Spectra Performed. </li></ul></ul><ul><ul><li>Gradients studied for a reduced sample. </li></ul></ul><ul><li>To be done: </li></ul><ul><ul><li>Fully automatic 2D analysis. </li></ul></ul><ul><ul><li>Detail comparison with SDSS. </li></ul></ul>
  33. 33. 3D Spectroscopy Summary <ul><li>IFS is a common user technique (40% of the observations done with the 3.5m at CAHA, 80% of one of the UT/VLT). </li></ul><ul><li>Many of proposed or new generations instruments are IFUs (MUSE, MEGARA). </li></ul><ul><li>JWST will include an IFU. </li></ul><ul><li>There is science that can only be done with IFUs. </li></ul><ul><li>Any future astronomer should be prepared to use it. </li></ul>

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