1301.0617
The X-ray/SZ view of the virial region. I. Thermodynamic properties
Eckert, et al
Measure the thermodynamic properties of cluster outer regions to provide constraints on the processes that rule the formation of large scale structures. Derive the thermodynamic properties of IC gas (T, S) by combining SZ thermal pressure from Planck and X-ray gas density from ROSAT; allows reconstruction T and S profiles out to virial radius and beyond, in a large sample of objects. Find S rises steadily with radius, albeit at a somewhat lower rate than predicted by self-similar expectations. Relaxed systems appear to follow the self-similar expectations more closely than perturbed objects. Results indicate that the well-known entropy excess observed in cluster cores extends well beyond the central regions. When correcting for the gas depletion, the observed entropy profiles agree with the prediction from gravitational collapse only, especially for cool-core clusters.
[*]1301.0620
Inside out and upside down: tracing the assembly of a simulated disk galaxy using mono-age stellar populations
Bird, .. Weinberg, .. Madau, et al
MW-like disk galaxy simulations, trace SF within disk. At z=0, <2Gyr stars mainly occupy the stellar spheroid, with the oldest stars having more centrally concentrate profiles. The younger populate disks of progressively longer radial scale length and shorter vertical scale height. At a given radius, superposition of old, vertically-extended and young, vertically-cmopact stars gives rise to a double-exponential profiles like that observed in the MW (although the superposition is continuous and smooth). Formation history: find that the trends of spatial structure and kinematics with stellar age are largely iprinted at birth, or immediately thereafter. Stars that form during the active merger phase at z>3 are quickly scattered into rounded, kinematically hot configurations. The oldest disk stars form in structures that are radially compact and relatively thick, while subsequent stars form in progressively larger, thinner, colder configurations from gas with increasing levels of rotational support. The disk thus forms "inside-out" in a radial sense and "upside-down" in a vertical sense. Secular heating and radial migration influence the final state of each star, but the changes they produce are small compared to the trends established at formation. The predicted correlations of stellar age with spatial and kinematic structure are in good qualitative agreement with the correlations observed for mono-abundance stellar populations in the MW.
1301.0631
The EGNoG survey: gas excitation in normal galaxies at z~0.3
Bauermeister, Blitz, ... et al
Important to understand the conditions of gas in systems of high-z and low SFR to properly infer their molecular gas content. The rotational transition of CO provide an excellent probe of gas excitation conditions in these galaxies. Present results from the gas excitation sample of the Evolution of molecular Gas in Normal Galaxies survey at CARMA. Report robust detections of both CO 1-0 and 3-2 lines in 3 galaxies (SFR 40-65 Msun/yr, 2e11 Msun) out of 4. Conclude that the excitation of the gas in these massive, highly SF galaxies is consistent with normal SF galaxies such as local spirals, not SB systems like the local ULIRGs. Since the survey selects from MS SF galaxies, this result is applicable to studies of MS galaxies at intermediate and high z; supports assumptions made in studies that find molecular gas fractions in SF galaxies at z~1-2 to be an order of magnitude larger than what is observed locally.
1301.0655
Metal-mass-to-light ratios of the Perseus cluster out to the virial radius
Matsushita et al
XMM-Newton data of Perseus to ~1Mpc (0.5 r_vir); use flux ratios of Lya of H-like Si and S to Ka line of He-like Fe, the abundance ratios of Si/Fe and S/Fe of the ICM derived using some plasma code. Temperature dependence of the line ratio limits the systematic uncertainty in the derived abundance ratio. The Si/Fe and S/Fe in ICM show no radial gradient. The emission-weighted averages of Se/Fe and S/Fe ratios outside the cool core are 0.92 in solar units. Indicates most Fe was synthesized by SNIa. Collect K-band luminosities of galaxies and calculate the ratio of Fe and Si mass in the ICM to K-band luminosity, Fe-mass-to-light ratio (IMLR) and Si-Mass-to-light ratio (SMLR); within ~1Mpc, the cumulative IMLR and SMLR increase with radius. Using the cumulative IMLR profile, discuss the past SNIa rate.
1301.0776
The Atacama cosmology telescope: likelihood for small-scale CMB data
Dunkley ... Das, ... et al
ACT measured CMB fluctuations to arcminute scales; at small scales the fluctuations in the primordial CMB become increasingly obscured by extragalactic FG and secondary CMB signals. Present results from a 9 parameter model describing these secondary effects, including the thermal and kinematic SZ and kSZ power; the clustered and Poisson-like power from CIB sources, and their frequency scaling; the tSZ-CIB correlation coefficient; the extragalactic radio source power; and thermal dust emission from Galactic cirrus in two different regions of the sky. In order to extract cosmological parameters, describe a likelihood function for the ACT data, fitting this model to the multi-frequency spectra in the multipole range 500<ell<10000. Extend the likelihood to include spectra from SPT at 3 different frequencies. Accounting for different radio source levels and Galactic cirrus emission, the same model provides and excellent fit to both datasets simultaneously, with chi2/dov=675/697 for ACT, and 96/107 for SPT. Then use the multi-frequency likelihood to estimate the CMB power spectrum from ACT in bandpowers, marginalizing over the secondary parameters. This provides a simplified 'CMB-only' likelihood in the rate 500<ell<3500 for use in cosmological parameter estimation.
1301.0780
The Atacama Cosmology Telescope: the stellar content of galaxy clusters selected using the Sunyaev-Zel'dovich effect
Hilton et al
Measurement of the stellar mass component of galaxy clusters selected via SZ. Measure 3.6 and 4.5 um galaxy luminosity functions, characterize m* and faint-end slope (alpha) to be similar to those for IR-selected cluster samples. Scaling of Y500/y0 with BCG stellar mass and total cluster stellar mass. See no evidence for a shortfall of baryons relative to the cosmic mean value.
1301.0816
The Atacama cosmology telescope: Sunyaev-Zel'dovich selected galaxy clusters at 148 GHz from three seasons of data
Hasselfield et al
A catalog of 68 clusters, 19 are new.
1301.0824
The Atacama cosmology telescope: cosmological parameters from three seasons of data
Sievers et al
Present constraints on cosmological and astrophysical parameters from hihg-res microwave background maps at 148 GHz and 218 GHz by ACT. Power of ell^2 C_ell/2pi of tSZ power spectrum measured at 3.4 muK^2 at ell=3000, kSZ has upper limit (95% CL) at 8.6 muK^2. Combine ACT with WMAP7, find excellent consistency with LCDM. Constrain the number of effective relativistic degrees of freedom in the early universe to be Neff=2.78 pm 0.55, in agreement with canonical value of Neff=3.046 for 3 massless neutrinos. Constrain sum of neutrino mass to be Sigma m_nu < 0.39 eV at 95% CL with ACT, WMAP7, BAO and H0 combined. Constrain amount of primordial He to be Yp=0.226pm0.032, and measure no variation in the fine structure constant alpha since recombination. Find no evidence for any running of the scalar spectral index: dns/dlnk = -0.003pm0.013.
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