We have carried out a systematic search for close supermassive black hole binaries (with sub-parsec separations) among z < ∼ 0.7 quasars observed spectroscopically in the Sloan Digital Sky Survey. Such binaries are predicted by models of supermassive black hole and host galaxy co-evolution, therefore their census and population properties constitute an important test of these models. Our working hypothesis is that one of the two black holes accretes at a much higher rate than the other and carries with it the only broad-emission line region of the system, making the system analogous to a single-lined spectroscopic binary star. Accordingly, we used an automatic technique based on spectroscopic principal component analysis to search for broad Hβ emission lines that are displaced from the rest-frame of the quasar by |∆v| > ∼ 1, 000 km s −1 (corresponding to binary periods and separations of P ∼ few × 100 yr and a ∼ few × 0.1 pc, respectively, for masses ∼ 10 8 M ⊙ ). This method can also yield candidates for rapidly recoiling black holes since their spectroscopic signature is similar. Our search yielded 88 candidates, several of which were previously identified and discussed in the literature. The widths of the broad Hβ lines are typical among quasars but the shifts are extreme. We found a correlation between the peak offset and skewness of the broad Hβ profiles (there is an extended wing on the opposite side of the profile from the shifted peak), which suggests that the profiles we have selected share a common physical explanation. The general properties of the narrow emission lines are typical of quasars. We carried out followup spectroscopic observations of 68 objects to search for changes in the peak velocities of the Hβ lines (the time interval in the observer's frame between the original and new observations is 1-10 yr and 5.7-10.0 yr in 2/3 of the cases). We measured statistically significant changes (at 99% confidence) in 14 objects, with resulting accelerations between −120 and +120 km s −1 yr −1 . The above results, taken at face value, are broadly consistent with predictions for the number of close supermassive binaries in the Sloan Digital Sky Survey quasar sample. However, such a comparison is complicated by several theoretical and observational uncertainties, such as the fact that the observable we employ to select objects depends on a combination of several degenerate intrinsic parameters of a binary. We emphasize that interpretation of the offset broad emission lines as signatures of supermassive binaries is subject to many significant caveats. Many more followup observations over a long temporal baseline are needed to characterize the variability pattern of the broad lines and test that this pattern is indeed consistent with orbital motion. The possibility that some of the objects in this sample are rapidly recoiling black holes remains open as the available data do not provide strong constraints for this scenario.

Uniform hexagonal hematite (α-Fe(2)O(3)) nanoplates have been synthesized by a facile alcohol-thermal reaction, and a new nanostructure of α-Fe(2)O(3) has been proposed. Each nanoplate is enclosed by (0001) basal planes and {1012} side surfaces. The phase, size, shape, and growth orientation of these nanocrystals were characterized by powder X-ray diffraction and electron microscopy. The thickness and diameter of these nanocrystals could be finely tuned by the selective use of alcohol solvent with increasing carbon atom number in the linear alkyl chain. A variety of nanocrystals with systemically changeable shapes from nanoplates to nanograins have been obtained. Specific adsorption of alcohol molecules on polar (0001) facets is proposed to be the main issue to modify the growth behavior of hematite nanocrystals. The presence of distilled water and the addition of sodium acetate have also been investigated. Either of them has a great influence on the growth of hematite nanocrystals, and shape-controlled growth can be rationally achieved. In addition, the post-aging of as-grown hematite nanocrystals in alcohol and distilled water has also been described. Both vibration spectroscopy (i.e., FTIR and Raman) and electronic spectra (diffused reflectance spectra) of these nanocrystals with a continuing shape change show a highly shape-dependent nature.

The kinematic Sunyaev-Zel'dovich (KSZ) effect-the Doppler boosting of cosmic microwave background (CMB) photons due to Compton scattering off free electrons with nonzero bulk velocity-probes the abundance and the distribution of baryons in the Universe. All KSZ measurements to date have explicitly required spectroscopic redshifts. Here, we implement a novel estimator for the KSZ-large-scale structure cross-correlation based on projected fields: it does not require redshift estimates for individual objects, allowing KSZ measurements from large-scale imaging surveys. We apply this estimator to cleaned CMB temperature maps constructed from Planck and WMAP data and a galaxy sample from the Wide-field Infrared Survey Explorer (WISE). We measure the KSZ effect at 3.8σ-4.5σ significance, depending on the use of additional WISE galaxy bias constraints. We verify that our measurements are robust to possible dust emission from the WISE galaxies. Assuming the standard Λ cold dark matter cosmology, we directly constrain (f_{b}/0.158)(f_{free}/1.0)=1.48±0.19 (statistical error only) at redshift z≈0.4, where f_{b} is the fraction of matter in baryonic form and f_{free} is the free electron fraction. This is the tightest KSZ-derived constraint reported to date on these parameters. Astronomers have long known that baryons do not trace dark matter on ∼ kiloparsec scales and there has been strong evidence that galaxies are baryon poor. The consistency between the f_{b} value found here and the values inferred from analyses of the primordial CMB and big bang nucleosynthesis verifies that baryons approximately trace the dark matter distribution down to ∼ megaparsec scales. While our projected-field estimator is already competitive with other KSZ approaches when applied to current data sets (because we are able to use the full-sky WISE photometric survey), it will yield enormous signal-to-noise ratios when applied to upcoming high-resolution, multifrequency CMB surveys.

The kinematic Sunyaev-Zel'dovich (kSZ) signal is a powerful probe of the cosmic baryon distribution. The kSZ signal is proportional to the integrated free electron momentum rather than the electron pressure (which sources the thermal SZ signal). Since velocities should be unbiased on large scales, the kSZ signal is an unbiased tracer of the large-scale electron distribution, and thus can be used to detect the "missing baryons" that evade most observational techniques.While most current methods for kSZ extraction rely on the availability of very accurate redshifts, we revisit a method that allows measurements even in the absence of redshift information for individual objects. It involves cross-correlating the square of an appropriately filtered cosmic microwave background (CMB) temperature map with a projected density map constructed from a sample of large-scale structure tracers. We show that this method will achieve high signal-to-noise when applied to the next generation of high-resolution CMB experiments, provided that component separation is sufficiently effective at removing foreground contamination. Considering statistical errors only, we forecast that this estimator can yield S/N ≈ 3, 120 and over 150 for Planck, Advanced ACTPol, and a hypothetical Stage-IV CMB experiment, respectively, in combination with a galaxy catalog from WISE, and about 20% larger S/N for a galaxy catalog from the proposed SPHEREx experiment. We show that the basic estimator receives a contribution due to leakage from CMB lensing, but that this term can be effectively removed by either direct measurement or marginalization, with little effect on the kSZ significance. We discuss possible sources of systematic contamination and propose mitigation strategies for future surveys. We compare the theoretical predictions to numerical simulations and validate the approximations in our analytic approach.This work serves as a companion paper to the first kSZ measurement with this method, where we used CMB temperature maps constructed from Planck and WMAP data, together with galaxies from the WISE survey, to obtain a 3.8 -4.5σ detection of the kSZ 2 amplitude. PACS numbers: 98.80.-k, 98.70.Vc

The non-zero mass of neutrinos suppresses the growth of cosmic structure on small scales. Since the level of suppression depends on the sum of the masses of the three active neutrino species, the evolution of large-scale structure is a promising tool to constrain the total mass of neutrinos and possibly shed light on the mass hierarchy. In this work, we investigate these effects via a large suite of N -body simulations that include massive neutrinos using an analytic linear-response approximation: the Cosmological Massive Neutrino Simulations (MassiveNuS). The simulations include the effects of radiation on the background expansion, as well as the clustering of neutrinos in response to the nonlinear dark matter evolution. We allow three cosmological parameters to vary: the neutrino mass sum M ν in the range of 0-0.6 eV, the total matter density Ω m , and the primordial power spectrum amplitude A s . The rms density fluctuation in spheres of 8 comoving Mpc/h (σ 8 ) is a derived parameter as a result. Our data products include N -body snapshots, halo catalogues, merger trees, raytraced galaxy lensing convergence maps for four source redshift planes between z s =1-2.5, and ray-traced cosmic microwave background lensing convergence maps. We describe the simulation procedures and code validation in this paper. The data are publicly available at