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

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)

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

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

Background

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

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

HI look back

HI 21cm Emission at High Redshift

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 M HI * = 6.3 ×10 9 M  (HIPASS, Zwaan et al. 2005)

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

Giant Metrewave Radio Telescope

GMRT Antenna Positions

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

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

Observational Targets

Table of Targets TargetTypez Look Back Time GMRT Obs Time Subaru Field field galaxies with H  emission Gyr80.5 hours Abell 370 cluster and surroundings Gyr70 hours Cl cluster and surroundings Gyr hours

Galaxy Cluster Abell 370

RA DEC 27’ × 27’ Cluster Centre

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

HI Abell literature redshifts but σ z ≥ ± 300 kms -1 Upper limit M HI = 1.3 M HI * with 95% confidence

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

The Subaru Field - H  emission galaxies

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

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

SDF uv coverage Subaru Field is equatorial

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

Self Calibration

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

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

Continuum Images Thumbnails 20’’ sq

Fuzzy RC Integrated Flux =  mJy

Fuzzy B galaxy UGC at redshift z=

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 5 th decimal place before converting to degrees/hours, minutes, seconds format eg   10h 33m 53.24s

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

Radio Continuum of the Subaru Galaxies

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

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

Subaru Galaxies – Continuum Thumbnails 10’’ sq

Halpha vs. RC line from Sullivan et al. 2001

Neutral Hydrogen in the Subaru Galaxies

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

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

2dF spectrum good good spectrum

2dF spectrum poor not so great spectrum

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

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

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

HI spectrum all 112 redshifts Neutral Hydrogen measurement M HI =  0.12 M HI *

HI spectrum bright Log H  Luminosity > 41 erg s redshifts Neutral Hydrogen measurement M HI = 0.57  0.26 M HI *

HI spectrum faint Log H  Luminosity  40.4 erg s redshifts Neutral Hydrogen measurement M HI = 0.31  0.19 M HI *

HI spectrum mid 40.4 < Log H  Luminosity  41 erg s redshifts Neutral Hydrogen measurement M HI =  0.44  0.20 M HI *

HI redshift mine all taking into account narrow band (H  ) filter shape – brighter galaxies will be seen over a larger volume

Future Work: Galaxy Cluster Cl

Galaxy Cluster Cl RA DEC 21’ × 21’ Cluster Centre

Galaxy Cluster Cl RA DEC ~1’ × 1’

Cl Data HST imaging  2181 galaxies with morphologies of which 195 spectroscopically confirmed cluster members (Treu et al. 2003) H α narrow 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) hours GMRT observations

Cl0024 positions GMRT Beam 50% level

Cl0024 z slice GMRT HI freq limits

PhD Timetable of Completion Rest of 2006: finish analysis of the Subaru Field (to be completed by the end of August 2006) analysis of galaxy cluster Cl (analysis to be finished by January 2007) optical imaging of galaxy cluster Abell 370 using SSO 40 inch and AAOmega follow-up to get redshifts – Mike Pracy doing much of this but I will be involved 2007: complete analysis of galaxy cluster Abell 370 (to be finished no later than June 2007) write up my thesis throughout 2007  finish between September 2007 & March 2008 (3½ - 4 year mark)

The End

Additional Slides

The UV Plane

Model no error

model

B mag vs. Halpha Lum

UV Plane

Stellar Mass Density Dickenson et al. 2003

HI spectrum bright faint M HI = 0.41  0.15 M HI *

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

Galaxy Cluster Abell 370 originally started working on this data in 3 month project – worked on to learn radio astronomy 42 literature redshifts for Abell 370 cluster members  33 are usable – large error in σ z ≥ ± 300 kms -1 (from Soucail et al )

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?