The%20Evolution%20of%20Stars%20and%20Gas%20in%20Galaxies:

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

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Those that deserve special mentions

• Brian Schmidt
• Agris Kalnajs
• Michael Pracy
• Tony Martin-Jones
• Scott Croom (AAO) Rob Sharp (AAO)
• Nissim Kanekar (NRAO)

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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, z0.4)
• to study galaxies in a variety of different
  environments
• UNIQUE PART ? to study galaxy properties in the
  same systems optically selected galaxies

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Background
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Star Formation Rate
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HI redshift
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HI look back
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HI 21cm Emission at High Redshift
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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)

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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

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Giant Metrewave Radio Telescope
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GMRT Antenna Positions
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GMRT Collecting Area

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

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Method of HI Detection
Radio Data Cube

• pick out HI signal using optical redshifts
• coadd faint signals to make measurement

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Observational Targets
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Table of Targets
Target Type z Look Back Time GMRT Obs Time
Subaru Field field galaxies with H? emission 0.24 2.8 Gyr 80.5 hours
Abell 370 cluster and surroundings 0.37 4.0 Gyr 70 hours
Cl00241654 cluster and surroundings 0.39 4.2 Gyr 18 45 hours
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Galaxy Cluster Abell 370
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Galaxy Cluster Abell 370
27 27
RA
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Galaxy Cluster Abell 370
3 3
RA
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HI Abell 370
33 literature redshifts but sz 300 kms-1
Upper limit MHI 1.3 MHI with 95
confidence
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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

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The Subaru Field - H? emission galaxies
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Subaru Field
24 30
Fujita et al. 2003 narrow band imaging - H?
emission flux
RA
We used 2dF to get redshifts
DEC
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SDF positions
Blue Points ? Subaru galaxies Red Points ? NVSS
Radio Continuum Sources
GMRT beam 10 level
GMRT beam 50 level
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SDF uv coverage
Subaru Field is equatorial
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Image of Dirty Beam
radio equivalent of optical point spread function
image 7 7
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Self Calibration
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Deepest GMRT Image
RMS 16 ?Jy
Field 10 12 12
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Sad cont sources
From AIPS auto detection routine - SAD Blue gt 5
mJy Red gt 1 mJy Black gt 0.32 mJy Grey gt 80
?Jy RMS 16 ?Jy
Subaru Field boundary
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Continuum Images
Thumbnails 20 sq
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Fuzzy RC
Integrated Flux 17.035 ? 0.077 mJy
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Fuzzy B
galaxy UGC 05849 at redshift z0.026045
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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

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Position change
Rounding error ?0.18 DEC ?2.7
RA PROBLEMS 2dF fibre diameter is 2 many
galaxies smaller than 2
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Radio Continuum of the Subaru Galaxies
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Sullivan et al. 2003
Sullivan et al. 2001 H? Luminosity vs. 1.4
GHz Luminosity UV Luminosity vs. 1.4 GHz
Luminosity
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Subaru Galaxies - B magnitude
Thumbnails 10 sq Ordered by H? luminosity
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Subaru Galaxies Continuum
Thumbnails 10 sq
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Halpha vs. RC
line from Sullivan et al. 2001
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Neutral Hydrogen in the Subaru Galaxies
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Subaru Galaxies - B magnitude
Thumbnails 10 sq Ordered by H? luminosity
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Subaru Galaxies - redshifts
Thumbnails 10 sq Ordered by H? luminosity
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2dF spectrum good
good spectrum
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2dF spectrum poor
not so great spectrum
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Redshift histogram
112 redshifts in GMRT data
GMRT HI freq range
Subaru Narrow Band Filter FWHM (120 Å)
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Galaxy Sizes
Variety of sizes measured size at 25th mag
arcsec-2 isophote
Thumbnails 10 sq Ordered by H? luminosity
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Diameter HI
smoothed beam FWHM 5.3 (20 kpc)
smoothed beam FWHM 8.0 (30 kpc)
unsmoothed beam FWHM 3 (10 kpc)
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HI spectrum all

• 112 redshifts
• Neutral Hydrogen
• measurement
• MHI 0.071
• 0.12 MHI

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HI spectrum bright

• Log H? Luminosity
• gt 41 erg s-1
• 36 redshifts
• Neutral Hydrogen
• measurement
• MHI 0.57
• 0.26 MHI

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HI spectrum faint

• Log H? Luminosity
• ? 40.4 erg s-1
• 33 redshifts
• Neutral Hydrogen
• measurement
• MHI 0.31
• 0.19 MHI

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HI spectrum mid

• 40.4 lt Log H? Luminosity
• ? 41 erg s-1
• 43 redshifts
• Neutral Hydrogen
• measurement
• MHI ?0.44 ? 0.20 MHI

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HI redshift mine all
taking into account narrow band (H?) filter shape
brighter galaxies will be seen over a larger
volume
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Future Work Galaxy Cluster Cl00241654
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Galaxy Cluster Cl00241654
21 21
RA
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Galaxy Cluster Cl00241654
1 1
RA
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Cl00241654 Data

• HST imaging ? 2181 galaxies with morphologies of
  which 195 spectroscopically confirmed cluster
  members (Treu et al. 2003)
• Ha 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)
• 18 45 hours GMRT observations

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Cl0024 positions
GMRT Beam 50 level
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Cl0024 z slice
GMRT HI freq limits
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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 Cl00241652 (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)

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The End
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Additional Slides
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The UV Plane
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Model no error
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model
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B mag vs. Halpha Lum
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UV Plane
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Stellar Mass Density
Dickenson et al. 2003
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HI spectrum bright faint
MHI 0.41 ? 0.15 MHI
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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

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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
  sz 300 kms-1 (from Soucail et al.
  1988 )

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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?