Searching for Reionization

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Searching for Reionization

• Ue-Li Pen ???

Jeff Peterson,CMU
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Reionization

• First objects
• 21cm _at_ zgt6
• 50-200 Mhz
• ?T 23 mK, 0.3 mJy
• Angular scale 5ltTlt20, freq res 500 khz

z10 simulation, Furlanetto et al, 2004
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21CMA/PAST

• Funded by NOAC, 1m spent, 1m this year, 3m
  total
• Differs in approach from LOFAR, MWA focused EOR
  experiment, fixed NCP pointing, high gain
  antennae, PC correlators, TV components, CMB
  style fisher analysis
• 20000 m2 effective area

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21CMA/PAST Site
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Software correlator
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Single baseline U-V map data
Almost no interference, excellent u-v coverage
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Single day, single baseline, prototype
12 correlating pods of 127 antenna each 24h
integration many extragalactic sources
NCP
3C061.1
100-200 Mhz, 10o FOV
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Meteor reflections
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Analysis

• From CMB field generalized pixels
• Eg. CBI, DASI
• Linear algebra based on Fisher matrices, Wiener
  filters for foregrounds
• Linear measurement equation (Beam solving)

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Indian Giant Meterwave Radio Telescope
30 dishes _at_40m ea. Operates in 2m
band Collaborators Y. Gupta (chief scientist),
Rajaram Nityananda (director), R. Subramanian
(Raman)
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GMRT Search

• Operating telescope, 37000m2, up to 32 Mhz BW,
  polarized correlator, lowest band 100-200 Mhz.
  Biggest collecting area in this band.
• Half in central 1km core, rest in 50 km Y.
• Currently hits RFI limit after a few minutes of
  integration power lines, TV stations, HAM
  amateurs, faulty home electronics. Exploration of
  new RFI mitigation schemes, software correlator.

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GMRT 150 Mhz image By Ishwara Chandra
(NCRA) Image noise 2 mJy Thermal limit 0.5 mJy
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Lag-Frequency plot
freq
100 hz
50 hz
lag
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Large Volume Simulations
100 Mpc 4 billion particle simulation I. Iliev,
G. Mellema 1 degree FOV
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Comoving distances
Low l anomaly model primary CMB to l20
CMB
reionization
ISW lensing map predictions
T-E correlations can be predicted!
EoR
Pen 2003
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Conclusions

• Several experiments operating or under
  construction. Detection will be very
  challenging 10mK.
• GMRT and 21CMA/PAST currently processing initial
  data. First detection goals largest structures
  (gt10 Mpc), lowest redshift. QSOs?
• Simulations will be challenging and crucial for
  the interpretation of initial data.
• Potential new window on universe, with very large
  numbers of structures with redshift Lensing,
  precision cosmology.