A Gunn-Peterson test with a QSO at z=6.4

Abstract

Understanding the cosmic re-ionization is one of the key goals of the modern observational cosmology. High redshift QSO spectra can be used as background light sources to measure absorption by intervening neutral hydrogen. We investigate neutral hydrogen absorption in a deep, moderate-resolution Keck/Deimos spectrum of QSO CFHQSJ2329-0301 at z=6.4. This QSO is one of the highest redshift QSOs presently known at z=6.4 but is 2.5 mag fainter than a previously well-studied QSO SDSSJ1148+5251 at z=6.4. Therefore, it has a smaller Stromgren sphere, and allows us to probe the highest redshift hydrogen absorption to date. The average transmitted flux at 5.915<z_abs<6.365 (200 comoving Mpc) is consistent with zero, in Ly_alpha, Ly_beta, and Ly_gamma absorption measurements. This corresponds to the lower limit of optical depth, tau_eff>4.9. These results are consistent with strong evolution of the optical depth at z>5.7.

5 pages, 4 figures. Accepted for publication in MNRAS

Cited by in corpus (21)

• Diffuse Lyman-alpha Halos around Galaxies at z=2.2-6.6: Implications for Galaxy Formation and Cosmic Reionization
• New synthesis models of consistent extragalactic background light over cosmic time
• Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum
• 21 cm signal from cosmic dawn: Imprints of spin temperature fluctuations and peculiar velocities
• On the use of semi-numerical simulations in predicting the 21-cm signal from the epoch of reionization
• SILVERRUSH. VII. Subaru/HSC Identifications of 42 Protocluster Candidates at z~6-7 with the Spectroscopic Redshifts up to z=6.574: Implications for Cosmic Reionization
• CHORUS II. Subaru/HSC Determination of the Ly$\alpha$ Luminosity Function at $z=7.0$: Constraints on Cosmic Reionization Model Parameter
• Spectroscopic observation of Ly$\alpha$ emitters at z~7.7 and implications on re-ionization
• A New Method to Measure the Post-Reionization Ionizing Background from the Joint Distribution of Lyman-$\alpha$ and Lyman-$\beta$ Forest Transmission
• Prediction of the 21-cm signal from reionization: comparison between 3D and 1D radiative transfer schemes
• The effect of peculiar velocities on the epoch of reionization (EoR) 21-cm signal
• Statistics of the epoch of reionization 21-cm signal - I. Power spectrum error-covariance
• The Shape and Size distribution of HII Regions near the percolation transition
• Studying the morphology of HI isodensity surfaces during reionization using Shapefinders and percolation analysis
• Effects of the sources of reionization on 21-cm redshift-space distortions
• No Ly$\alpha$ emitters detected around a QSO at z=6.4: Suppressed by the QSO?
• Large-scale environment of z~5.7 CIV absorption systems I: projected distribution of galaxies
• SILVERRUSH. IX. Lya Intensity Mapping with Star-Forming Galaxies at z=5.7 and 6.6: A Possible Detection of Extended Lya Emission at $\gtrsim$100 comoving kpc around and beyond the Virial-Radius Scale of Galaxy Dark Matter Halos
• Spectroscopy of the spatially-extended Lya emission around a QSO at z=6.4
• Subaru medium-resolution spectra of a QSO at z=6.62: Three reionization tests
• Impact of the primordial fluctuation power spectrum on the reionization history