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Cheblet bases for galaxy modeling: a new tool for surveys

Cheblet bases for galaxy modeling: a new tool for surveys. Yolanda Jiménez Teja Txitxo Benítez Lozano Instituto de Astrofísica de Andalucía (CSIC) Departamento de Astronomía Extragaláctica E-mail: yojite@iaa.es. ALHAMBRA: http://arxiv.org/abs/0806.3021

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Cheblet bases for galaxy modeling: a new tool for surveys

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  1. Cheblet bases for galaxy modeling: a new tool for surveys Yolanda Jiménez Teja Txitxo Benítez Lozano Instituto de Astrofísica de Andalucía (CSIC) Departamento de Astronomía Extragaláctica E-mail: yojite@iaa.es

  2. ALHAMBRA: http://arxiv.org/abs/0806.3021 • PAU: http://fr.arxiv.org/abs/0807.0535 • CLASH Large photometric redshift surveys • Photometry measurements • Morphological features • Linear • Flexible • Capable of modelling both the bulge and the disk of extended galaxies. Galaxies decomposition method Cheblet bases for galaxy modeling: a new tool for surveys Outline Motivation Mathematical background Visualization Examples Applications Conclusions

  3. Chebyshev polynomial: Chebyshev rational function: Cheblet bases for galaxy modeling: a new tool for surveys Outline Motivation Mathematical background Visualization Examples Applications Conclusions

  4. Chebyshev rational functions in r Fourier series in θ , with Cheblet bases for galaxy modeling: a new tool for surveys The Cheblet polar basis is separable in r and θ: Outline Motivation Mathematical background Visualization Examples Applications Conclusions

  5. Cheblet bases for galaxy modeling: a new tool for surveys Cheblet polar basis functions Outline Motivation Mathematical background Visualization C-F basis Wings Examples Applications Conclusions

  6. Cheblet bases for galaxy modeling: a new tool for surveys Cheblet polar basis functions Outline Motivation Mathematical background Visualization C-F basis Wings Examples Applications Conclusions

  7. Sèrsic Exponential Gaussian Moffat-Lorentzian Cheblet bases for galaxy modeling: a new tool for surveys The wings of the basis functions tend to vanish, so the light flux is bounded by the basis: Outline Motivation Mathematical background Shapelets Visualization C-F basis Wings Examples Cheblet basis Applications Conclusions

  8. Cheblet bases for galaxy modeling: a new tool for surveys Outline Sersic Motivation Mathematical background Visualization Examples Applications Conclusions De Vaucouleurs

  9. Cheblet bases for galaxy modeling: a new tool for surveys S G C

  10. Cheblet bases for galaxy modeling: a new tool for surveys Outline Radial profile Motivation Mathematical background Visualization Examples Applications Conclusions Radial flux

  11. Cheblet bases for galaxy modeling: a new tool for surveys Clusters processing • Method 1 • One-by-one processing of the objects, taking different frames. • Method 2 • Simultaneous processing of the objects, centering a grid in each object. Outline Motivation Mathematical background Visualization Examples Applications Conclusions

  12. Cheblet bases for galaxy modeling: a new tool for surveys ABELL1703 (F850) (arXiv:1004.4660)

  13. Cheblet bases for galaxy modeling: a new tool for surveys ABELL1703 (F435) (arXiv:1004.4660)

  14. Cheblet bases for galaxy modeling: a new tool for surveys ABELL1703 (F435) (arXiv:1004.4660)

  15. Cheblet bases for galaxy modeling: a new tool for surveys Clusters pipeline • Settling the grid and evaluation of the Cheblet basis with some certain n1_max and n2_max. • Ortonormalization of the basis functions: Modified Gram-Schmidt Method  SLOWEST STEP! • Storing the orthonormalized basis. • Calculation of the optimal number of coefficients n1 and n2: Chi2 minimization. • Extraction of the corresponding basis functions for those optimal n1 and n2. • Evaluation of the Cheblet coefficients. • Building the model with these coefficients. • Repeat the process from 4th step for each filter. Outline Motivation Mathematical background Visualization Examples Applications Conclusions

  16. Centroid: • Rms radius: • Ellipticity: Cheblet bases for galaxy modeling: a new tool for surveys Object shape measurement Outline If we define Motivation Mathematical background • Flux: Visualization Practical implementation then some morphological parameters can be calculated by means of the C-F coefficients: Examples Applications Conclusions

  17. Cheblet bases for galaxy modeling: a new tool for surveys Not only galaxies but also arcs: Original Model Residual

  18. Cheblet bases for galaxy modeling: a new tool for surveys • Cheblet bases have proved to be a highly reliable method to analyze galaxy images, with better results than GALFIT and shapelet techniques. Outline Motivation • Cheblet bases allow us to efficiently reproduce the morphology of the galaxies and measure their photometry. Mathematical background Visualization • PSF deconvolution is easily implemented due to the bases linearity. Examples Applications • Different morphological parameters can be directly inferred from Cheblet coefficients, with great accuracy. Conclusions • Not only single image processing is possible, but also cluster images, just overlapping grids with origin on the different object centers.

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