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Register a new userA Measurement of the Millimeter Emission and the Sunyaev-Zeldovich Effect Associated with Low-Frequency Radio Sources
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We present a statistical analysis of the millimeter-wavelength properties of 1.4 GHz-selected sources and a detection of the Sunyaev-Zeldovich (SZ) effect associated with the halos that host them. The Atacama Cosmology Telescope (ACT) has conducted a survey at 148 GHz, 218 GHz and 277 GHz along the celestial equator. Using samples of radio sources selected at 1.4 GHz from FIRST and NVSS, we measure the stacked 148, 218 and 277 GHz flux densities for sources with 1.4 GHz flux densities ranging from 5 to 200 mJy. At these flux densities, the radio source population is dominated by active galactic nuclei (AGN), with both steep and flat spectrum populations, which have combined radio-to-millimeter spectral indices ranging from 0.5 to 0.95, reflecting the prevalence of steep spectrum sources at high flux densities and the presence of flat spectrum sources at lower flux densities. The thermal SZ effect associated with the halos that host the AGN is detected at the 5$sigma$ level through its spectral signature. When we compare the SZ effect with weak lensing measurements of radio galaxies, we find that the relation between the two is consistent with that measured by Planck for local bright galaxies. We present a detection of the SZ effect in some of the lowest mass halos (average $M_{200}approx10^{13}$M$_{odot}h_{70}^{-1}$) studied to date. This detection is particularly important in the context of galaxy evolution models, as it confirms that galaxies with radio AGN also typically support hot gaseous halos. With Herschel observations, we show that the SZ detection is not significantly contaminated by dust. We show that 5 mJy$<S_{1.4}<$200 mJy radio sources contribute $ell(ell+1)C_{ell}/(2pi)=0.37pm0.03mu$K$^2$ to the angular power spectrum at $ell=3000$ at 148 GHz, after accounting for the SZ effect associated with their host halos.
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We present a new measurement of the kinetic Sunyaev-Zeldovich effect (kSZ) using Planck cosmic microwave background (CMB) and Baryon Oscillation Spectroscopic Survey (BOSS) data. Using the `LowZ North/South galaxy catalogue from BOSS DR12, and the group catalogue from BOSS DR13, we evaluate the mean pairwise kSZ temperature associated with BOSS galaxies. We construct a `Central Galaxies Catalogue (CGC) which consists of isolated galaxies from the original BOSS data set, and apply the aperture photometry (AP) filter to suppress the primary CMB contribution. By constructing a halo model to fit the pairwise kSZ function, we constrain the mean optical depth to be $bar{tau}=(0.53pm0.32)times10^{-4}(1.65,sigma)$ for `LowZ North CGC, $bar{tau}=(0.30pm0.57)times10^{-4}(0.53,sigma)$ for `LowZ South CGC, and $bar{tau}=(0.43pm0.28)times10^{-4}(1.53,sigma)$ for `DR13 Group. In addition, we vary the radius of the AP filter and find that the AP size of $7,{rm arcmin}$ gives the maximum detection for $bar{tau}$. We also investigate the dependence of the signal with halo mass and find $bar{tau}=(0.32pm0.36)times10^{-4}(0.8,sigma)$ and $bar{tau}=(0.67pm0.46)times10^{-4}(1.4,sigma)$ for `DR13 Group with halo mass restricted to, respectively, less and greater than its median halo mass, $10^{12}, h^{-1}{rm M}_{odot}$. For the `LowZ North CGC sample restricted to $M_{rm h} gtrsim 10^{14}, h^{-1}{rm M}_odot$ there is no detection of the kSZ signal because these high mass halos are associated with the high-redshift galaxies of the LowZ North catalogue, which have limited contribution to the pairwise kSZ signals.
In this paper we probe the hot, post-shock gas component of quasar-driven winds through the thermal Sunyaev-Zeldovich (tSZ) effect. Combining datasets from the Atacama Cosmology Telescope, the $textit{Herschel}$ Space Observatory, and the Very Large Array, we measure average spectral energy distributions (SEDs) of 109,829 optically-selected, radio quiet quasars from 1.4~GHz to 3000~GHz in six redshift bins between $0.3<z<3.5$. We model the emission components in the radio and far-infrared, plus a spectral distortion from the tSZ effect. At $z>1.91$, we measure the tSZ effect at $3.8sigma$ significance with an amplitude corresponding to a total thermal energy of $3.1times10^{60}$ ergs. If this energy is due to virialized gas, then our measurement implies quasar host halo masses are $sim6times10^{12}~h^{-1}$M$_odot$. Alternatively, if the host dark matter halo masses are $sim2times10^{12}~h^{-1}$M$_odot$ as some measurements suggest, then we measure a $>$90 per cent excess in the thermal energy over that expected due to virialization. If the measured SZ effect is primarily due to hot bubbles from quasar-driven winds, we find that $(5^{+1.2}_{-1.3}$) per cent of the quasar bolometric luminosity couples to the intergalactic medium over a fiducial quasar lifetime of 100 Myr. An additional source of tSZ may be correlated structure, and further work is required to separate the contributions. At $zleq1.91$, we detect emission at 95 and 148~GHz that is in excess of thermal dust and optically thin synchrotron emission. We investigate potential sources of this excess emission, finding that CO line emission and an additional optically thick synchrotron component are the most viable candidates.
High-frequency, high-resolution imaging of the Sunyaev-Zeldovich (SZ) effect is an important technique to study the complex structures of the atmospheres of merging galaxy clusters. Such observations are sensitive to the details of the electron spectrum. We show that the morphology of the SZ intensity maps in simulated galaxy clusters observed at 345 GHz, 600 GHz, and 857 GHz are significantly different because of SZ relativistic corrections. These differences can be revealed by high-resolution imaging instruments. We calculate relativistically corrected SZ intensity maps of a simulated, massive, merging galaxy cluster and of the massive, merging clusters 1E0657-558 (the Bullet Cluster) and Abell 2219. The morphologies of the SZ intensity maps are remarkably different between 345 GHz and 857 GHz for each merging cluster. We show that high-resolution imaging observations of the SZ intensity maps at these frequencies, obtainable with the LABOCA and HERSCHEL-SPIRE instruments, allow to fully exploit the astrophysical relevance of the predicted SZ morphological effect.
In the standard hot cosmological model, the black-body temperature of the Cosmic Microwave Background (CMB), $T_{rm CMB}$, increases linearly with redshift. Across the line of sight CMB photons interact with the hot ($sim10^{7-8}$ K) and diffuse gas of electrons from galaxy clusters. This interaction leads to the well known thermal Sunyaev-Zeldovich effect (tSZ), which produces a distortion of the black-body emission law, depending on $T_{rm CMB}$. Using tSZ data from the ${it Planck}$ satellite it is possible to constrain $T_{rm CMB}$ below z=1. Focusing on the redshift dependance of $T_{rm CMB}$ we obtain $T_{rm CMB}(z)=(2.726pm0.001)times (1+z)^{1-beta}$ K with $beta=0.009pm0.017$, improving previous constraints. Combined with measurements of molecular species absorptions, we derive $beta=0.006pm0.013$. These constraints are consistent with the standard (i.e. adiabatic, $beta=0$) Big-Bang model.
Stacking cosmic microwave background (CMB) maps around known galaxy clusters and groups provides a powerful probe of the distribution of hot gas in these systems via the Sunyaev-Zeldovich (SZ) effect. A stacking analysis allows one to detect the average SZ signal around low mass halos, and to extend measurements out to large scales, which are too faint to detect individually in the SZ or in X-ray emission. In addition, cross correlations between SZ maps and other tracers of large-scale structure (with known redshifts) can be used to extract the redshift-dependence of the SZ background. Motivated by these exciting prospects, we measure the two-point cross-correlation function between a catalog of $sim 380,000$ galaxy groups (with redshifts spanning $z=0.01-0.2$) from the Sloan Digital Sky Survey (SDSS) and Compton-y parameter maps constructed by the Planck collaboration. We find statistically significant correlations between the group catalog and Compton-y maps in each of six separate mass bins, with estimated halo masses in the range $10^{11.5-15.5} M_odot/h$. We compare these measurements with halo models of the SZ signal, which describe the stacked measurement in terms of one-halo and two-halo terms. The one-halo term quantifies the average pressure profile around the groups in a mass bin, while the two-halo term describes the contribution of correlated neighboring halos. For the more massive groups we find clear evidence for the one- and two-halo regimes, while groups with mass below $10^{13} M_odot/h$ are dominated by the two-halo term given the resolution of Planck data. We use the signal in the two-halo regime to determine the bias-weighted electron pressure of the universe: $langle b P_e rangle= 1.50 pm 0.226 times 10^{-7}$ keV cm$^{-3}$ (1-$sigma$) at $zapprox 0.15$.
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