HI 21cm Tomography of IGM: freq 100 to 200 MHz

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HI 21cm Tomography of IGM freq 100 to 200 MHz
Furlanetto, Zaldarriaga 2004
z12
9

• Large scale structure ?, f(HI) , Temp (K, CMB,
  Spin)
• Advantages 3D, optically thin, dominant baryon
  component
• Tomography requires SKA
• ?TB(2) 10s mK
• SKA rms(100hr) 4mK
• LOFAR rms (1000hr) 80mK

0.5Mpc
7.6
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Challenge Low frequency foreground hot,
confused sky Eberg 408 MHz Image (Haslam 1982)
0.5 to 5.0 GHz

• Coldest regions T 100 (?/200 MHz)-2.6 K
• Highly confused 1 source/deg2 with S140 gt 1
  Jy
• Synch. smooth 100MHz vs. 21cm lines 1 MHz

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Chromatic aberration Frequency differencing with
MHz channels doesnt work well due to frequency
dependent far-out sidelobes
142, 174 MHz
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Simulation effects of residual calibration errors
6C source counts gt 1Jy (Smax 200 Jy)
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UVSUB real-time source removal
IMLIN post-processing freq fitting (3rd order)
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Datta 09
0.1
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For errors constant over 1 day DNR requirement
0.2 calibration errors
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Datta Bowman in prep
300 hours 0.1 calibration errors
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Cosmic Stromgren Sphere

• Accurate host redshift from CO z6.419/0.001
• Ly a, high ioniz lines inaccurate redshifts (?z
  gt 0.03)
• Proximity effect photons leaking from
  6.32ltzlt6.419

White et al. 2003
z6.32

• time bounded Stromgren sphere R 4.7 Mpc
• tqso 1e5 R3 f(HI) 1e7yrs
• or
• f(HI) 1 (tqso/1e7 yr)

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Loeb Rybicki 2000
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CSS Constraints on neutral fraction at z6

• Nine z6 QSOs with CO or MgII redshifts ltRgt
  4.4 Mpc (Wyithe et al. 05 Fan et al. 06
  Kurk et al. 07)
• GP gt f(HI) gt 0.001
• If f(HI) 0.001, then lttqsogt 1e4 yrs
  implausibly short given QSO fiducial lifetimes
  (1e7 years)?
• Probability arguments size evolution suggest
  f(HI) gt 0.05

Wyithe et al. 2005
Fan et al 2006
P(gtxHI)
90 probability x(HI) gt curve
tqso/4e7 yrs
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