J. Borrill

Planck intermediate results XI

We present the scaling relation between Sunyaev-Zeldovich (SZ) signal and stellar mass for almost 260,000 locally brightest galaxies (LBGs) selected from the Sloan Digital Sky Survey (SDSS). These are predominantly the central galaxies of their dark matter halos. We calibrate the stellar-to-halo mass conversion using realistic mock catalogues based on the Millennium Simulation. Applying a multi-frequency matched filter to the Planck data for each LBG, and averaging the results in bins of stellar mass, we measure the mean SZ signal down to M-* similar to 2 x 10(11) M-circle dot, with a clear indication of signal at even lower stellar mass. We derive the scaling relation between SZ signal and halo mass by assigning halo properties from our mock catalogues to the real LBGs and simulating the Planck observation process. This relation shows no evidence for deviation from a power law over a halo mass range extending from rich clusters down to M-500 similar to 2 x 10(13) M-circle dot, and there is a clear indication of signal down to M-500 similar to 4 x 10(12) M-circle dot. Plancks SZ detections in such low-mass halos imply that about a quarter of all baryons have now been seen in the form of hot halo gas, and that this gas must be less concentrated than the dark matter in such halos in order to remain consistent with X-ray observations. At the high-mass end, the measured SZ signal is 20 % lower than found from observations of X-ray clusters, a difference consistent with the magnitude of Malmquist bias effects that were previously estimated for the X-ray sample.

Planck intermediate results IX

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic “haze” at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b | ~ 35−50° in Galactic latitude and | l | ~ 15−20° in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of −2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∝ E-2.1. At Galactic latitudes | b | < 30°, the microwave haze morphology is consistent with that of the Fermi gamma-ray “haze” or “bubbles”, while at b ~ −50° we have identified an edge in the microwave haze that is spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied.