arXiv subjects

Z. Haiman

Publications and source records attributed to Z. Haiman.

40 records · Page 3Linked to original sources

arXiv2003

Small-scale CMB Temperature and Polarization Anisotropies due to Patchy Reionization

We study contributions from inhomogeneous (patchy) reionization to arcminute scale ($1000 < \ell < 10,000$) cosmic microwave background (CMB) anisotropies. We show that inhomogeneities in the ionization fraction, rather than in the mean density, dominate both the temperature and the polarization power spectra. Depending on the ionization history and the clustering bias of the ionizing sources, we find that rms temperature fluctuations range from 2 $μ$K to 8 $μ$K and the corresponding values for polarization are over two orders of magnitude smaller. Reionization can significantly bias cosmological parameter estimates and degrade gravitational lensing potential reconstruction from temperature maps but not from polarization maps. We demonstrate that a simple modeling of the reionization temperature power spectrum may be sufficient to remove the parameter bias. The high-$\ell$ temperature power spectrum will contain some limited information about the sources of reionization.

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arXiv2002

Probing the Reionization History of the Universe using the Cosmic Microwave Background Polarization

The recent discovery of a Gunn--Peterson (GP) trough in the spectrum of the redshift 6.28 SDSS quasar has raised the tantalizing possibility that we have detected the reionization of the universe. However, a neutral fraction (of hydrogen) as small as 0.1% is sufficient to cause the GP trough, hence its detection alone cannot rule out reionization at a much earlier epoch. The Cosmic Microwave Background (CMB) polarization anisotropy offers an alternative way to explore the dark age of the universe. We show that for most models constrained by the current CMB data and by the discovery of a GP trough (showing that reionization occurred at z > 6.3), MAP can detect the reionization signature in the polarization power spectrum. The expected 1-sigma error on the measurement of the electron optical depth is around 0.03 with a weak dependence on the value of that optical depth. Such a constraint on the optical depth will allow MAP to achieve a 1-sigma error on the amplitude of the primordial power spectrum of 6%. MAP with two years (Planck with one year) of observation can distinguish a model with 50% (6%) partial ionization between redshifts of 6.3 and 20 from a model in which hydrogen was completely neutral at redshifts greater than 6.3. Planck will be able to distinguish between different reionization histories even when they imply the same optical depth to electron scattering for the CMB photons.

astro-ph↗

arXiv2000

Probing Early Structure Formation with Far-Infrared Background Correlations

The large-scale structure of high-redshift galaxies produces correlated anisotropy in the far-infrared background (FIRB). In regions of the sky where the thermal emission from Galactic dust is well below average, these high-redshift correlations may be the most significant source of angular fluctuation power over a wide range of angular scales, from about 7' to about 3 degrees, and frequencies, from about 400 to about 1000 GHz. The strength of this signal should allow detailed studies of the statistics of the FIRB fluctuations, including the shape of the angular power spectrum at a given frequency and the degree of coherence between FIRB maps at different frequencies. The FIRB correlations depend upon and hence constrain the redshift-dependent spectral energy distributions, number counts, and clustering bias of the galaxies and active nuclei that contribute to the background. We quantify the accuracy to which Planck and a newly proposed balloon-borne mission EDGE could constrain models of the high-redshift universe through the measurement of FIRB fluctuations. We conclude that the average bias of high-redshift galaxies could be measured to an accuracy of less than approximately 1% or, for example, separated into 4 redshift bins with about 10% accuracy.

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arXiv2000

The Discovery of a Luminous z=5.80 Quasar from the Sloan Digital Sky Survey

We present observations of SDSSp J104433.04--012502.2, a luminous quasar at z=5.80 discovered from Sloan Digital Sky Survey (SDSS) multicolor imaging data. This object was selected as an i'-band dropout object, with i*=21.8 +/- 0.2, z*=19.2 +/- 0.1. It has an absolute magnitude M1450 = -27.2 (H_0 =50 km/s/Mpc, q0 = 0.5). The spectrum shows a strong and broad Ly alpha emission line, strong Ly alpha forest absorption lines with a mean continuum decrement D_A = 0.91, and a Lyman Limit System at z=5.72. The spectrum also shows strong OI and SiIV emission lines similar to those of quasars at z<= 5, suggesting that these metals were produced at redshift beyond six. The lack of a Gunn-Peterson trough in the spectrum indicates that the universe is already highly ionized at z ~ 5.8. Using a high-resolution spectrum in the Ly alpha forest region, we place a conservative upper limit of the optical depth due to the Gunn-Peterson effect of tau < 0.5 in regions of minimum absorption. The Ly alpha forest absorption in this object is much stronger than that in quasars at z<= 5. The object is unresolved in a deep image with excellent seeing, implying that it is unlensed. The black hole mass of this quasar is ~3 x 10^9 M_solar if we assume that it is radiating at the Eddington luminosity and no lensing amplification, implying that it resides in a very massive dark matter halo. The discovery of one quasar at M_1450 < -27 in a survey area of 600 deg^2 is consistent with an extrapolation of the observed luminosity function at lower redshift. The abundance and evolution of such quasars can provide sensitive tests of models of quasar and galaxy formation.

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