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Epoch of Reionization Tomography with the CSO

Epoch of Reionization Tomography with the CSO. Wide-field C+ spectral mapping and correlation with HI Matt Bradford CSO NSF visit: October 12, 2011. Epoch of Reionization. First UV sources turn on and reionize the HI.

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Epoch of Reionization Tomography with the CSO

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  1. Epoch of Reionization Tomography with the CSO Wide-field C+ spectral mapping and correlation with HI Matt Bradford CSO NSF visit: October 12, 2011 Matt Bradford

  2. Epoch of Reionization • First UV sources turn on and reionize the HI. • Quasars + WMAP => redshift ~20 to 6 (0.3-1 Gyr after the Big Bang) • Details not clear. Ionizing sources? Pop III stars and/or AGN, Pop II stars. In terms of galaxy counts, reionization dominated by sources at the low-luminosity end of the distribution, at or below threshold in current or JWST surveys. Matt Bradford

  3. 21 cm Probes Galaxies at Reionization Furlanetto et al. 2006: Mean 21 cm signal against CMB through reionization. Beforehand, spin temp in equilibrium with CMB. Wouthuysen-Field effect: HI is coupled to matter temperature via absorption of UV photons early in reionization. Shows absorption against CMB. Pop III stars, less efficiency W-F coupling As reionization proceeds, X-rays heat IGM, bring HI into emission Pop II stars Shapiro et al., 2008 All HI eventually destroyed Matt Bradford

  4. But mean absolute spectrum is hard to measure -> look at fluctuations Reionization maps in HI, 94 comovingMpc across at z=7.7. McQuinn et al. 2007. Ionized (white) and neutral (black) gas via 21 cm. Patch sizes related to ionizing source sizes (large or small galaxies). • PAPER: http://astro.berkeley.edu/~dbacker/eor/ • MWA: http://www.mwatelescope.org/ Matt Bradford

  5. Tomography in C+Y. Gong, A. Cooray, et al. First-principles calculation of mean intensity of C+ as a function of redshift under various assumptions, including painting on to numerical sims (DeLucia and Blaizot (2007). Matches with simple scalings form star formation history estimates. arxiv.org/1107.3553v1 Matt Bradford

  6. Tomography in C+ Background-limited sensitivity relative to the mean intensity. This gets much harder at earlier times. Power spectrum measurement requires only fractional SNR in each spatial-spectral bin (voxel) • Lower-redshift measurement in 650, 850 micron windows a first step. Matt Bradford

  7. Tomography in C+: Power SpectraY. Gong, A. Cooray, et al. The aggregate glow of undetected small galaxies. Shot-noise dominates, but clustering enters at low k. Error bars based on Z-Spec like instrument scaled up to 64 spatial pixels, and R=700 with 312 spectral pixels -> 20,000 total detectors.  Need integral field on-chip spectrometers. Assume mapping 16 square degrees with 4000 hours total. Basic sensitivity independent of aperture; for z=7, SNR per spectral / spatial voxel is ~5e-3 in 1 h arxiv.org/1107.3553v1 Matt Bradford

  8. Cross correlation C+ with HIY. Gong, A. Cooray, et al. Basic C+ sensitivity independent of aperture, but would like to probe angular scales which show inversion of correlation with HI. • Large scales: HI anticorrelated with galaxies which produce reionizing photons. • Anti-correlation disappears on scales of the ionizing bubble size. arxiv.org/1107.3553v1 • 10m aperture for C+ is well-suited to comparison with 21-cm experiments. • a potential long-term future CSO experiment: automated, low overhead, if the instrumentation can be developed. Matt Bradford

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