http://arxiv.org/abs/1501.01445
We cross-correlate a template of the matter density field tracing the large-scale filamentary distribution of the Warm-Hot Intergalactic Medium out to ~90 Mpc/h with foreground cleaned Planck Nominal Cosmic Microwave Background (CMB) maps. The template traces the projected matter density reconstructed from the Two-Micron All-Sky Redshift Survey of galaxies and models the spatial distribution of filaments. After applying a filtering technique in order to reduce the unwanted 1/f noise in the CMB data and potential large-scale foreground residuals, we find a marginal signal with a signal-to-noise from 0.84 to 1.39 at the different Planck frequencies, and with a frequency dependence compatible with the thermal Sunyaev-Zel’dovich (tSZ) effect. At the 95% confidence level we set an upper limit to the cross-correlation at zero lag of < 0.17 muK. These results were obtained in a region covering 60% of the full sky, which is left after masking out the Galaxy, point sources and galaxy clusters. The significance of this signal is marginally increased after combining all Planck frequencies, and also under more restrictive Galactic masks. It extends out to 6 deg, which at the median depth of our template corresponds to a physical length of ~6-8 Mpc/h. Using a log-normal model to describe the weakly nonlinear density field we predict the signal for a template tracing the matter distribution. We combine the predictions from this model with the previous upper limit to constrain the temperature of the shock-heated WHIM. We find that our upper limit is compatible with a fraction of 45% of all baryons residing in filaments at overdensities ~1-100 and with temperatures in the range 10^5.5-10^7 K, in agreement with a detection at redshift z ~ 0.5.
R. Genova-Santos, F. Atrio-Barandela, F. Kitaura, et. al.
Thu, 8 Jan 15
3/48
Comments: Submitted to ApJ. 14 pages, 7 figures
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