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SDSS

SDSS. The Sloan Digital Sky Survey. Mapping The Universe. The SDSS is Two Surveys. The Fuzzy Blob Survey. The Squiggly Line Survey. The Site. The telescope 2.5 m mirror. 1.3 MegaPixels $150. 4.3 Megapixels $850. 100 GigaPixels $10,000,000. Digital Cameras. CCDs.

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SDSS

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  1. SDSS The Sloan Digital Sky Survey

  2. Mapping The Universe

  3. The SDSS is Two Surveys The Fuzzy Blob Survey The Squiggly Line Survey

  4. The Site

  5. The telescope • 2.5 m mirror

  6. 1.3 MegaPixels $150 4.3 Megapixels $850 100 GigaPixels $10,000,000 Digital Cameras

  7. CCDs

  8. CCDs: Drift Scan Mode

  9. The SDSS ATLAS of GALAXIES

  10. HUBBLE's TUNING FORK DIAGRAM

  11. NGC 450

  12. NGC 1055

  13. NGC 4437

  14. NGC 5792

  15. NGC 1032

  16. NGC 4753

  17. NGC 60

  18. NGC 5492

  19. NGC 936

  20. NGC 5750

  21. NGC 3521

  22. NGC 2967

  23. NGC 5719

  24. UGC 01962

  25. NGC 1087

  26. NGC 5334

  27. UGC 05205

  28. UGC 07332

  29. UGCA 285

  30. Arp 240

  31. UCG 08584

  32. NGC 799 NGC 800

  33. NGC 428

  34. UGC 10770

  35. Measuring Quantities From the Images: The Photo pipeline

  36. [asinh( ) + ln(b)] f/f0 –2.5 m = 2b ln (10) How do you measure brightness? Most People use Magnitudes m = –2.5 Log (flux) + C We use Luptitudes

  37. OK, but how do you measure flux? Isophotal magnitudes: What we don’t do

  38. OK, but how do we measure flux? Petrosian Radius: Surface brightness Ratio =0.2 Petrosion flux: Flux within 2 Petrosian Radii

  39. Some Other Measures PSF magnitudes Fiber magnitudes

  40. Galaxy Models • de Vaucouleurs magnitudes: • assume profile associated with ellipiticals I=I0 exp {-7.67[(r/re)1/4]} • Exponential magnitudes: • Assume profile associated with spirals I=I0 exp {-1.68(r/re)} Model magnitudes pick best

  41. Which Magnitudes to Use?

  42. Other Image Parameters • Size • Type • psfMag – expMag > 0.145 • Many hundreds of others

  43. SPECTRA

  44. An Astronomical Primer of Stellar Spectra

  45. O B A F G K M L T h e ine irl/Guy iss e Stellar Spectral Types ong ime

  46. O Stellar Spectra

  47. B Stellar Spectra

  48. A Stellar Spectra

  49. F Stellar Spectra

  50. G Stellar Spectra

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