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Conference SummaryUe-Li Pen
Overview
Young, vibrant field!Rapid progress: searching for needles in a
haystack.Lots of technical developmentsInterest and impact in many related science
fieldsPossibly leading field in papers/data pointFirst maps and power spectra of HI at z>0.5
25 years ago: 21cm @ z=9 foreground subtraction. Bebbington 1986
WSRT-LFFE Partial LOFAR
First all sky 150 MHz map!
Parsons et al, PAPER
400m
…5% prototype for 80-300 MHzLooking through a telescope on observing trip
MWA 32 tiles (32T)
32T Pipeline First Light
20°x 20°Zenith
103 MHz
134 MHz
180 MHz
• Observations from January 2010
• 3 x 7hr tracks with real-time calibration, peeling, imaging, resampling and averaging.
• HEALPIX projection of Pic A field.
• Pic A peeled to reveal many secondary sources.
• Several simplifying assumptions relative to the 512T version, but all of the pieces are in place.
Robert C Byrd Telescope: 100m
760 MHz, z=0.87
SVD foreground subtracted, frequency dependent beam corrected
100x rescaled: 100 μK 21cm signal
W. ReichZadar Foreground Conference17
Polarized intensity all-sky surveys
22.8 GHz WMAP (Page et al. 2007)22.8 GHz WMAP (Page et al. 2007)1.4 GHz: DRAO (Wolleben et al., 2006) 1.4 GHz: DRAO (Wolleben et al., 2006) + Villa Elisa (Testori et al., 2008)+ Villa Elisa (Testori et al., 2008)
depolarization
Both surveys on absolute zero-level ! Low intrinsic percentage polarization outside of local features.
APS analysis of 1.4 GHz survey (La Porta et al., 2006, 455, 9L ) + extrapolation ~70 GHz optimal frequency to detect B-mode
Wish list for future instrument
Stable: no moving partsStable: minimal active elementsAnalysis: Whole sky small field of viewSymmetry: GBT is steerable: uniform maps. At 5x
longer wavelength: E-W rotation invariance due to earth rotation. N-S rotation invariance if placed on aircraft carrier.
Compromise: wide N-S cylinders. Optical E-W FFT, digital N-S FFT, continuous frequency compensation, no mode mixing, no w-term!
CMU cylinder under construction: U. Seljak, J. Peterson, K. Bandura, K. Sigurdson
Summary of Summary
Vibrant new young field.More opportunities for cross experiment
interactions.Many approaches and data sets under way!“Understanding the galactic and extragalactic
foregrounds”: first 1000x subtraction of foregrounds at 15’, 800MHz to reach 100 μK 21cm signal, with zero understanding.
Special thanks
To Vibor and Marjan for organizing a great and successful conference!