期刊
ASTRONOMY & ASTROPHYSICS
卷 586, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201526328
关键词
cosmic background radiation; cosmology: observations; large-scale structure of Universe; galaxies: clusters: intracluster medium
资金
- ESA
- CNES (France)
- CNRS/INSU-IN2P3-INP (France)
- ASI (Italy)
- CNR (Italy)
- INAF (Italy)
- NASA (USA)
- DoE (USA)
- STFC (UK)
- UKSA (UK)
- CSIC (Spain)
- MINECO (Spain)
- JA (Spain)
- RES (Spain)
- Tekes (Finland)
- AoF (Finland)
- CSC (Finland)
- DLR (Germany)
- MPG (Germany)
- CSA (Canada)
- DTU Space (Denmark)
- SER/SSO (Switzerland)
- RCN (Norway)
- SFI (Ireland)
- FCT/MCTES (Portugal)
- ERC (EU)
- PRACE (EU)
- ERC [307209]
- Marie Curie Career Integration Grant [CIG 294183]
- Spanish Ministerio de Economia y Competitividad [AYA2012-30789]
- Science and Technology Facilities Council [ST/F01239X/1, ST/K004131/1, ST/L000768/1, ST/N000056/1, ST/F010885/1, ST/K002821/1, ST/M001334/1, ST/J001368/1, ST/K001051/1] Funding Source: researchfish
- UK Space Agency [ST/H001212/1, ST/N001206/1, ST/K003674/1, ST/H001239/1, ST/N001095/1, ST/M007685/1] Funding Source: researchfish
By looking at the kinetic Sunyaev-Zeldovich effect (kSZ) in Planck nominal mission data, we present a significant detection of baryons participating in large-scale bulk flows around central galaxies (CGs) at redshift z approximate to 0.1. We estimate the pairwise momentum of the kSZ temperature fluctuations at the positions of the Central Galaxy Catalogue (CGC) samples extracted from Sloan Digital Sky Survey (SDSS-DR7) data. For the foreground-cleaned SEVEM, SMICA, NILC, and COMMANDER maps, we find 1.8-2.5 sigma detections of the kSZ signal, which are consistent with the kSZ evidence found in individual Planck raw frequency maps, although lower than found in the WMAP-9yr W-band (3.3 sigma). We further reconstruct the peculiar velocity field from the CG density field, and compute for the first time the cross-correlation function between kSZ temperature fluctuations and estimates of CG radial peculiar velocities. This correlation function yields a 3.0-3.7 sigma detection of the peculiar motion of extended gas on Mpc scales in flows correlated up to distances of 80-100 h(-1) Mpc. Both the pairwise momentum estimates and the kSZ temperature-velocity field correlation find evidence for kSZ signatures out to apertures of 8 arcmin and beyond, corresponding to a physical radius of >1 Mpc, more than twice the mean virial radius of halos. This is consistent with the predictions from hydrodynamical simulations that most of the baryons are outside the virialized halos. We fit a simple model, in which the temperature-velocity cross-correlation is proportional to the signal seen in a semi-analytic model built upon N-body simulations, and interpret the proportionality constant as an effective optical depth to Thomson scattering. We find tau(T) = (1.4 +/- 0.5) x 10(-4); the simplest interpretation of this measurement is that much of the gas is in a diffuse phase, which contributes little signal to X-ray or thermal Sunyaev-Zeldovich observations.
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