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The Evolution of Stars and Gas in Galaxies: PowerPoint Presentation
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The Evolution of Stars and Gas in Galaxies:

The Evolution of Stars and Gas in Galaxies:

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The Evolution of Stars and Gas in Galaxies:

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  1. The Evolution of Stars and Gas in Galaxies: A journey with noise and astrometry PhD Midterm Philip Lah

  2. Supervisor: Frank Briggs • Supervisory Panel: • Erwin de Blok (RSAA) • Jayaram Chengalur (National Centre for Radio Astrophysics, India) • Matthew Colless (Anglo-Australian Observatory) • Roberto De Propris (Cerro Tololo Inter-American Observatory, Chile)

  3. Those that deserve special mentions: • Brian Schmidt • Agris Kalnajs • Michael Pracy • Tony Martin-Jones • Scott Croom (AAO) & Rob Sharp (AAO) • Nissim Kanekar (NRAO)

  4. Goal of PhD • to relate the star formation rate, the stellar mass and the mass in neutral hydrogen gas in galaxies as they evolve • to examine galaxy evolution over last 4 Gyr, (a third of the age of the universe, z~0.4) • to study galaxies in a variety of different environments • UNIQUE PART to study galaxy properties in the same systems – optically selected galaxies

  5. Background

  6.  Hα Spectroscopy  Hα Narrow Band Imaging  UV (with no dust correction) Subaru Field Star Formation Rate

  7. Rao et al. 2006 Prochaska et al. 2005 Zwaan et al. 2005 HIPASS HI 21cm HI redshift

  8. HI look back

  9. HI 21cm Emission at High Redshift

  10. HI emission • HI – single atom of hydrogen – radiation from an excited state were proton & electron have the same spin - 10 million year half life • Assuming an optically thin neutral hydrogen cloud • MHI*= 6.3 ×109 M (HIPASS, Zwaan et al. 2005)

  11. Previous highest redshift HI Westerbork Synthesis Radio Telescope (WSRT) Netherlands Abell 2218 z = 0.18 integration time 36 days, Zwaan et al. 2001 Very Large Array (VLA) Abell 2192 z = 0.1887 integration time ~80 hours, Veheijen et al. 2004

  12. Giant Metrewave Radio Telescope

  13. GMRT Antenna Positions

  14. GMRT Collecting Area 30 dishes of 45 m diameter GMRT Collecting Area  21 × ATCA  15 × Parkes  6.9 × WSRT  3.6 × VLA

  15. Frequency HI Redshift DEC RA Method of HI Detection Radio Data Cube • pick out HI signal using optical redshifts • coadd faint signals to make measurement

  16. Observational Targets

  17. Table of Targets

  18. Galaxy Cluster Abell 370

  19. DEC Cluster Centre Galaxy Cluster Abell 370 27’ × 27’ RA

  20. DEC Galaxy Cluster Abell 370 ~3’ × 3’ RA

  21. HI Abell 370 33 literature redshifts but σz ≥ ± 300 kms-1 Upper limit MHI = 1.3 MHI* with 95% confidence

  22. Galaxy Cluster Abell 370 • need more redshifts for reasonable analysis • the plan is to use WFI on SSO 40 inch for imaging – Mike Pracy took some data last year and hopefully take more this year • hopefully use AAOmega for spectroscopic follow-up in October/November 2006 • also made improvements to my data reduction methods so redo reduction

  23. The Subaru Field - H emission galaxies

  24. Subaru Field 24’ × 30’ Fujita et al. 2003 narrow band imaging - H emission flux RA We used 2dF to get redshifts DEC

  25. Blue Points  Subaru galaxies Red Points  NVSS Radio Continuum Sources SDF positions GMRT beam 10% level GMRT beam 50% level

  26. Subaru Field is equatorial SDF uv coverage

  27. Image of Dirty Beam radio equivalent of optical point spread function image 7’ × 7’

  28. Self Calibration

  29. Deepest GMRT Image RMS ~ 16 Jy Field 10 12’ × 12’

  30. From AIPS auto detection routine - SAD Blue > 5 mJy Red > 1 mJy Black > 0.32 mJy Grey > 80 Jy RMS ~ 16 Jy Sad cont sources Subaru Field boundary

  31. Continuum Images Thumbnails 20’’ sq

  32. Fuzzy RC Integrated Flux = 17.035  0.077 mJy

  33. Fuzzy B galaxy UGC 05849 at redshift z=0.026045

  34. Astrometry • need optical and radio positions to agree to a high level of precision • shift in radio data – corrected by comparing with FIRST continuum source positions • optical data – PROBLEM  coordinates that I had been given for the Subaru galaxies rounded to the 5th decimal place before converting to degrees/hours, minutes, seconds format eg. 10.56479302  10.56479  10h 33m 53.24s

  35. Rounding error: 0.18’’ DEC 2.7’’ RA PROBLEMS 2dF fibre diameter is 2’’ many galaxies smaller than 2’’ Position change

  36. Radio Continuum of the Subaru Galaxies

  37. Sullivan et al. 2001 H Luminosity vs. 1.4 GHz Luminosity & UV Luminosity vs. 1.4 GHz Luminosity Sullivan et al. 2003

  38. Subaru Galaxies - B magnitude Thumbnails 10’’ sq Ordered by H luminosity

  39. Subaru Galaxies – Continuum Thumbnails 10’’ sq

  40. Halpha vs. RC line from Sullivan et al. 2001

  41. Neutral Hydrogen in the Subaru Galaxies

  42. Subaru Galaxies - B magnitude Thumbnails 10’’ sq Ordered by H luminosity

  43. Subaru Galaxies - redshifts Thumbnails 10’’ sq Ordered by H luminosity

  44. 2dF spectrum good good spectrum

  45. 2dF spectrum poor not so great spectrum

  46. 112 redshifts in GMRT data Redshift histogram GMRT HI freq range Subaru Narrow Band Filter FWHM (120 Å)

  47. Galaxy Sizes Variety of sizes – measured size at 25th mag arcsec-2 isophote Thumbnails 10’’ sq Ordered by H luminosity

  48. smoothed beam FWHM ~5.3’ (20 kpc) Diameter HI smoothed beam FWHM ~8.0’ (30 kpc) unsmoothed beam FWHM ~3’ (10 kpc)

  49. HI spectrum all • 112 redshifts • Neutral Hydrogen • measurement • MHI = 0.071 • 0.12 MHI*

  50. Log H Luminosity > 41 erg s-1 36 redshifts • Neutral Hydrogen • measurement • MHI = 0.57 • 0.26 MHI* HI spectrum bright