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  1. 1. Quasar Spectra Astroinformatics Astronomy, Computer Science & Machine Learning
  2. 2. Quote <ul><li>&quot;… the community will realise that its lone-astronomer days are over, ... the subject has become too vast and complicated … … science can be realised only through code &quot; </li></ul><ul><li>Anne Finkbeiner (2010) </li></ul>
  3. 3. Astroinformatics? <ul><li>Machine Learning </li></ul><ul><li>Algorithms </li></ul><ul><li>Software Tools </li></ul><ul><li>Computer Science </li></ul><ul><li>SDSS Database </li></ul><ul><li>Virtual Observatory </li></ul><ul><li>Astronomy </li></ul><ul><li>Quasars </li></ul><ul><li>Spectroscopy </li></ul>
  4. 4. Astroinformatics? New Scientific Knowledge
  5. 5. Quasars – What are they? <ul><li>Which one is the Quasar? </li></ul>Dictionary (OED) : a massive and extremely remote celestial object, emitting exceptionally large amounts of energy, which typically has a starlike image. It has been suggested that quasars contain massive black holes ...
  6. 6. Quasars – The Theory <ul><li>Quasar : Quasi-stellar Radio Source </li></ul><ul><li>QSO : Quasar Stellar Object </li></ul><ul><li>Highly luminous Active Galatic Nucleus (AGN) at cosmological distances </li></ul><ul><li>Strong X-Ray emission, sometimes radio emission </li></ul><ul><li>Time-variable flux (days, weeks) </li></ul><ul><li>Broad AND Narrow emission lines </li></ul>
  7. 7. First Quasar (1963) <ul><li>3C 273, was emitting a huge amount of energy, with a very unusual never-before-seen spectrum. </li></ul><ul><li>Maarteen Schmidt analysed spectrum - realised they were hydrogen lines shifted an astonishing 16 percent toward the red. </li></ul><ul><li>(wired.com Science Discoveries) </li></ul>(Credit: Open University, Peterson 1997)
  8. 8. Spectral Energy Distribution (SED) <ul><li>Normal Galaxies: Peak in the optical </li></ul><ul><li>Quasars: Spectral Excess over wide range </li></ul><ul><li>Energy Distribution cannot be from stars alone </li></ul><ul><li>10% Radio Loud </li></ul>(Credit: Open University, Peterson 1997)
  9. 9. SDSS – Sloan Digital Sky Survey <ul><li>Spectrograph </li></ul><ul><li>Metal plate with fibres </li></ul><ul><li>640 spectra simultaneously </li></ul><ul><li>CCD Camera </li></ul><ul><li>Revolutionary </li></ul><ul><li>30 panels </li></ul><ul><li>4 million pixels </li></ul><ul><li>2.5m telescope , New Mexico </li></ul><ul><li>Wide field (3 Degree) </li></ul>
  10. 10. SDSS Database <ul><li>Data available to public </li></ul><ul><li>Tutorials, Software Tools, Help Desk </li></ul><ul><li>Database interface for Amatuers & Professionals </li></ul>
  11. 11. SDSS Database History of all jobs run. The red ones failed! <ul><li>Online SQL editor (Structured Query Language) </li></ul><ul><li>Save your results </li></ul>
  12. 12. Virtual Observatory (VO) <ul><li>The Reality : Great software but lots of duplication! USA one approach, Europe another, China another. </li></ul><ul><li>The Hope : International Virtual Observatory Alliance (IVOA) created in 2002 to standardise Astro Data access. </li></ul>
  13. 13. Machine Learning KMeans Clustering Choose any 2 starting points. Keep iterating until distance minimised. <ul><li>Principal Component Analysis (PCA) </li></ul><ul><li>Reduce High Dimensional Data to 2D or 3D </li></ul><ul><li>What attributes account for most variance? </li></ul>
  14. 14. Project: Current Status <ul><li>Virtual Observatory environment setup </li></ul><ul><li>Basic Data on 105,000 quasars downloaded & converted to database. </li></ul><ul><li>Corrupt data on SDSS identified </li></ul><ul><li>Outliers identified </li></ul><ul><li>Machine Learning alogrithms ready to go </li></ul>
  15. 15. Tools of the Trade <ul><li>Version Control </li></ul><ul><li>Backup, compare, merge, share code </li></ul><ul><li>If you program, use this! </li></ul>
  16. 16. Tools of the Trade <ul><li>Free, Open Source </li></ul><ul><li>MATLAB capabilities </li></ul><ul><li>Links to C, C++, FORTRAN, R etc </li></ul><ul><li>Numerical libraries and plotting </li></ul><ul><li>Becoming de facto open-source scientific environment </li></ul>
  17. 17. Tools of the Trade <ul><li>Teaches ”scientists and engineers the concepts, skills, and tools they need to use and build software more productively” </li></ul><ul><li>software-carpentry.org </li></ul>
  18. 18. Project: The Future <ul><li>Download 1000 detailed Quasar Spectra </li></ul><ul><li>Convert Spectrum to homogenous database </li></ul><ul><li>Run machine algorithms on data </li></ul><ul><li>Analyse anomolous emission spectra </li></ul>
  19. 19. Astroinformatics: The Future <ul><li>Large Synoptic Survey Telescope </li></ul><ul><li>Wide, Fast, Deep - Dark Energy </li></ul><ul><li>30 Terabytes nightly </li></ul><ul><li>Square Kilometre Array </li></ul><ul><li>Radio telescope – Gravity, first stars </li></ul><ul><li>~200 Terabytes nightly </li></ul><ul><li>Panoramic Survey Telescope </li></ul><ul><li>Hazardous objects, solar system </li></ul><ul><li>10 Terabytes nightly </li></ul>
  20. 20. Astroinformatics: The Future ? Experimental Science – Thousands of years ago Theoretical Science – Newton, Maxwell, Einstein Computational Science – Simulations, complexity Data Science – 4th Paradigm, Data Deluge (Tony Hey, Microsoft Research)
  21. 21. Astroinformatics: The Future <ul><li>” Now is the time for the recognition of Astroinformatics … The future of Astronomy depends on it.&quot; (Astroinformatics: A 21st Century Approach to Astronomy, KD Borne, 2009) </li></ul>

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