The Evolution of Stars and Gas in Galaxies

1. The Evolution of Stars and Gas in Galaxies PhD Thesis Proposal 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 (University of Bristol, UK)

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

4. Why do this? Should give a clearer picture of how, when and where stars and their host galaxies form. Improves our understanding of our place in the universe, residing in our galaxy, the Milky Way, and orbiting our star, the Sun.

5. Background

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

7. Stellar Mass Density Dickenson et al. 2003

8. Neutral Hydrogen Gas Mass

9. Neutral Hydrogen Gas Mass Storrie- Lombardi & Wolfe 2000 Rao & Turnshek 2003 HIPASS HI 21cm

10. Galaxy Environment • galaxy environment cluster, cluster outskirts and the field • density - morphology relation • density - star formation relation • density - neutral hydrogen relation • Cause of density relations?

11. HI 21cm Emission at High Redshift

12. 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

13. Giant Metrewave Radio Telescope

14. Giant Metrewave Radio Telescope

15. Giant Metrewave Radio Telescope

16. Giant Metrewave Radio Telescope

17. Giant Metrewave Radio Telescope

18. Giant Metrewave Radio Telescope

19. Giant Metrewave Radio Telescope

20. Giant Metrewave Radio Telescope

21. Giant Metrewave Radio Telescope

23. GMRT Antenna Positions

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

25. Method of HI Detection • individual galaxies HI 21cm emission below radio observational detection limits • large sample of galaxies with known positions & precise redshifts (from optical observations) • coadd weak HI signals isolated in position & redshift (velocity) space • measure integrated HI signal – total HI mass of whole galaxy population – can calculate the average HI galaxy mass

26. Observational Targets

27. Table of Targets

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

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

30. Abell 370 Data • 42 literature redshifts for Abell 370 cluster members 33 are usable – large error in σz ≥ ± 300 kms-1(from Soucail et al. 1988 ) • obtaining imaging data ESO 2.2m/WFI with VRI filters 34’ × 33’(queue scheduled by Sept) use to select sample for spectroscopic follow-up • using AF2/WYFFOS 4.2mWilliam Herschel Telescope, La Palma (sometime in Oct to Dec)  for redshifts and star formation rate from [OII]

31. Frequency HI Redshift DEC RA Radio Data Cube

32. galaxy redshift Spectrum through Cube

33. galaxy redshift Spectrum around Redshift

34. galaxy redshift Flux around Galaxy in Velocity Space

35. HI Abell 370

36. RMS decrease

37. Mass HI Assuming an optically thin neutral hydrogen cloud MHI*= 6.2 ×109 M (Zwaan et al. 2003)

38. Abell 370 HI Mass

39. DEC Cluster Centre Galaxy Cluster Cl0024+1654 21’ × 21’ RA

40. DEC Galaxy Cluster Cl0024+1654 ~1’ × 1’ RA

41. Cl0024+1654 Data • HST imaging  2181 galaxies with morphologies of which 195 spectroscopically confirmed cluster members (Treu et al. 2003) • Hαnarrow band imaging with Subaru  star formation rates(Kodama et al. 2004) • 296 literature redshifts within HI frequency limits of the GMRT observation (Cszoke et al. 2001) • estimated HI Mass Upper Limit similar to Abell 370: ~1.7 × 109M

42. Subaru Field RA 24’ × 30’ DEC

43. GMRT HI Freq Range Subaru Filter FWHM (120 Å) Subaru Field Redshifts

44. Subaru Field Redshifts number of target Hα emitting galaxies = 347 number of galaxies with quality ≥ 3 redshifts = 183 number of galaxies in GMRT HI freq range = 166

45. Past and Future Work

46. Previous Work started PhD 1st March 2004 • Mar to mid-July 1stThree Month Project - preliminary work on reducing Abell 370 GMRT data - creating data reduction pipeline • mid-July to Aug completed reduction of one sideband of the 7 days of data - prepared results for a GMRT telescope proposal for galaxy cluster Cl0024+1652 • Sept to mid-Nov 2ndThree Month Project - 6dFGS working with Robert Proctor and Duncan Forbes (Swinburne University) and Matthew Colless (AAO)

47. Previous Work • mid Nov to Dec Literature Review for Thesis Proposal • Jan 2005 traveled to India for GMRT observations galaxy cluster Cl0024+1652 • beginning of March 5 nights 2dF AAT redshift observations of the Subaru Field • have been working on adapting and revising data reduction code for all GMRT data sets – developing partially automated flagging of data

48. Future Work rest 2005: • finish data reduction code • reduce Subaru data and publish results • reduce Cl0024+1652 data and publish results • Abell 370 spectroscopic observations  using AF2/WYFFOS 4.2mWilliam Herschel Telescope, La Palma (sometime in Oct to Dec) – for redshifts and star formation rate from [OII]

49. Future Work 2006: • beginning year finish reducing Abell 370 data and publish results • once published Subaru results may go back to GMRT TAC for another sample of field galaxies • other possibilities: - obtain more redshifts for coadding particularly on the outskirts of the clusters - stellar mass measurements using redshifts and additional near-infrared imaging

50. Future Work 2007: • first 6 months - finish write up thesis / finish off anything left over from previous years