In order to investigate the growth of super-massive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line AGNs at z~1.4 in the Subaru XMM-Newton Deep Survey
field. In this redshift range, a significant part of the accretion growth of SMBHs is thought to be taking place. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad MgII line and the 3000A monochromatic luminosity. We supplement the MgII FWHM values with the Ha FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMF and ERDF are calculated using the Vmax method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMF and ERDF by applying the Maximum Likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local Universe, the corrected BHMF at z~1.4 has a higher number density above 10^8 Msolar but a lower number density below that mass range. The evolution may be indicative of a down-sizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDF from z=1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rate close to the Eddington-limit is higher at higher redshifts.
We present results of optical spectroscopic observations of the mass donor star in SS 433 with Subaru and Gemini, with an aim to best constrain the mass of the compact object. Subaru/FOCAS observations were performed on October 6-8 and 10, 2007, cove
ring the orbital phase of phi=0.96-0.26. We first calculate cross correlation function of these spectra with that of the reference star HD 9233 in the wavelength range of 4740-4840 Angstrom. This region is selected to avoid strong absorption lines accompanied with contaminating emission components. The same analysis is applied to archive data of Gemini/GMOS taken at phi=0.84-0.30 by Hillwig & Gies (2008). From the Subaru and Gemini CCF results, the amplitude of radial velocity curve of the donor star is determined to be 58.3+/-3.8 km s-1 with a systemic velocity of 59.2+/-2.5 km s-1. Together with the radial velocity curve of the compact object, we derive the mass of the donor star and compact object to be M_O=12.4+/-1.9 M_sun and M_X=4.3+/-0.6 M_sun, respectively. We conclude, however, that these values should be taken as upper limits. From the analysis of the averaged absorption line profiles of strong lines and weak lines observed with Subaru, we find evidence for heating effects from the compact object. Using a simple model, we find that the true radial velocity amplitude of the donor star could be as low as 40+/-5 km s-1 in order to produce the observed absorption-line profiles. Taking into account the heating of the donor star may lower the derived masses to M_O=10.4 +2.3/-1.9 M_sun and M_X=2.5 +0.7/-0.6 M_sun. Our final constraint, 1.9 M_sun< M_X <4.9 M_sun, indicates that the compact object in SS 433 is most likely a low mass black hole, although the possibility of a massive neutron star cannot be firmly excluded.
A-site ordered manganites LnBaMn1.96Fe0.04O5 and LnBaMn1.96Fe0.04O6 are investigated by x-ray full-profile diffraction and Moessbauer spectroscopy. Powder samples were oriented with preferred orientation of platy crystallites in the plane of sample s
urface. March-Dollase function of preferred orientation was employed in analysing both the Rietveld patterns and the Mossbauer spectra. Combined effects of preffered orientation and vibrational anisotropy on the line area asymmetry of Mossbauer doublet are analysed. Constructive and destructive interference between the effects of texture and vibrational anisotropy is observed in LnBaMn1.96Fe0.04O6 and LnBaMn1.96Fe0.04O5, respectively. Both series of the manganites show the main axis of electric field gradient perpendicular to layers (Vzz along c) with Vzz>0 in oxygen-poor series and Vzz<0 in oxygen-rich series. Charge-orbital order (COO) melting around Fe dopants explains the single-site spectra observed for several Ln in both O5 and O6 series, except LaBaMn1.96Fe0.04O5. However, the short-range COO persists to be observed in magnetization and in Rietveld patterns.
While synthesizing the single crystals of novel materials is not always feasible, orienting the layered polycrystals becomes an attractive method in the studies of angular dependencies of inelastic scattering of x-rays or neutrons. Putting in use the
Rietveld analysis of layered structures in novel manganites and cuprates we develop the studies of their anisotropic properties with oriented powders instead of single crystals. Densities of phonon states (DOS) and atomic thermal displacememts (ATD) are anisotropic in the A-site ordered manganites LnBaMn2Oy of both y=5 and y=6 series (Ln=Y, La, Sm, Gd). We establish the angular dependence of DOS on textures of arbitrary strengths, link the textures observed by x-ray and gamma-ray techniques, and solve the problem of disentanglement of Goldanskii-Karyagin effect (GKE) and texture in Moessbauer spectra.
