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!