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Background: The Density-constraint Time-dependent Hartree-Fock method is currently the tool of choice to predict fusion cross-sections. However, it does not include pairing correlations, which have been found recently to play an important role. Purpose: To describe the fusion cross-section with a method that includes the superfluidity and to understand the impact of pairing on both the fusion barrier and cross-section. Method: The density-constraint method is tested first on the following reactions without pairing, $^{16}$O+$^{16}$O and $^{40}$Ca+$^{40}$Ca. A new method is developed, the Density-constraint Time-dependent Hartree-Fock-Bogoliubov method. Using the Gogny-TDHFB code, it is applied to the reactions $^{20}$O+$^{20}$O and $^{44}$Ca+$^{44}$Ca. Results: The Gogny approach for systems without pairing reproduces the experimental data well. The DC-TDHFB method is coherent with the TDHFB fusion threshold. The effect of the phase-lock mechanism is shown for those reactions. Conclusions: The DC-TDHFB method is a useful new tool to determine the fusion potential between superfluid systems and to deduce their fusion cross-sections., Comment: 8 pages, 11 figures

Resonant enhancement of spin Seebeck effect (SSE) due to phonons was recently discovered in Y3Fe5O12 (YIG). This effect is explained by hybridization between the magnon and phonon dispersions. However, this effect was observed at low temperatures and high magnetic fields, limiting the scope for applications. Here we report observation of phonon-resonant enhancement of SSE at room temperature and low magnetic field. We observed in Lu2BiFe4GaO12 and enhancement 700 % greater than that in a YIG film and at very low magnetic fields around 10-1 T, almost one order of magnitude lower than that of YIG. The result can be explained by the change in the magnon dispersion induced by magnetic compensation due to the presence of non-magnetic ion substitutions. Our study provides a way to tune the magnon response in a crystal by chemical doping with potential applications for spintronic devices., Comment: 17 pages, 4 figures

A vibration isolation system called Type-Bp system used for power recycling mirrors has been developed for KAGRA, the interferometric gravitational-wave observatory in Japan. A suspension of the Type-Bp system passively isolates an optic from seismic vibration using three main pendulum stages equipped with two vertical vibration isolation systems. A compact reaction mass around each of the main stages allows for achieving sufficient damping performance with a simple feedback as well as vibration isolation ratio. Three Type-Bp systems were installed in KAGRA, and were proved to satisfy the requirements on the damping performance, and also on estimated residual displacement of the optics.

Major construction and initial-phase operation of a second-generation gravitational-wave detector KAGRA has been completed. The entire 3-km detector is installed underground in a mine in order to be isolated from background seismic vibrations on the surface. This allows us to achieve a good sensitivity at low frequencies and high stability of the detector. Bare-bones equipment for the interferometer operation has been installed and the first test run was accomplished in March and April of 2016 with a rather simple configuration. The initial configuration of KAGRA is named {\it iKAGRA}. In this paper, we summarize the construction of KAGRA, including the study of the advantages and challenges of building an underground detector and the operation of the iKAGRA interferometer together with the geophysics interferometer that has been constructed in the same tunnel., Comment: Resolution of some figures has been decreased from its original version submitted to a journal

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2m Subaru telescope on the summit of Maunakea in Hawaii. A team of scientists from Japan, Taiwan and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg$^2$ in five broad bands ($grizy$), with a $5\,\sigma$ point-source depth of $r \approx 26$. The Deep layer covers a total of 26~deg$^2$ in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg$^2$). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey., Comment: 14 pages, 7 figures, 5 tables. Corrected for a typo in the coordinates of HSC-Wide spring equatorial field in Table 5

We study the correlation between the [O III]$\lambda 5007$ and X-ray luminosities of local Active Galactic Nuclei (AGNs), using a complete, hard X-ray ($>10$ keV) selected sample in the Swift/BAT 9-month catalog. From our optical spectroscopic observations at the South African Astronomical Observatory and the literature, a catalog of [O III]$\lambda 5007$ line flux for all 103 AGNs at Galactic latitudes of $|b|>15^\circ$ is complied. Significant correlations with intrinsic X-ray luminosity ($L_{\rm X}$) are found both for observed ($L_{\rm [O~III]}$) and extinction-corrected ($L_{\rm [O~III]}^{\rm cor}$) luminosities, separately for X-ray unabsorbed and absorbed AGNs. We obtain the regression form of $L_{\rm [O~III]}$ $\propto L_{\rm 2-10\; keV}^{1.18\pm0.07}$ and $L_{\rm [O~III]}^{\rm cor}$ $\propto L_{\rm 2-10\; keV}^{1.16\pm0.09}$ from the whole sample. The absorbed AGNs with low ($<$0.5\%) scattering fractions in soft X-rays show on average smaller $L_{\rm [O~III]}/L_{\rm X}$ and $L_{\rm [O~III]}^{\rm cor}/L_{\rm X}$ ratios than the other absorbed AGNs, while those in edge-on host galaxies do not. These results suggest that a significant fraction of this population are buried in tori with small opening angles. By using these $L_{\rm [O~III]}$ vs. $L_{\rm X}$ correlations, the X-ray luminosity function of local AGNs (including Compton thick AGNs) in a standard population synthesis model gives much better agreement with the [O III]$\lambda 5007$ luminosity function derived from the Sloan Digital Sky Survey than previously reported. This confirms that hard X-ray observations are a very powerful tool to find AGNs with high completeness., Comment: 14 pages including 11 figures and 3 tables, accepted for publication in ApJ. In this manuscript, the observed 14-195 keV luminosities in Table 1 have been corrected to be exactly the same as in the original Swift/BAT 9-month catalog. Accordingly, Figures 2(a) and 3(a) and a part of Tables 2 and 3 have been updated. The changes from the previous version are small and do not affect the text

The understanding of how the sub-nanoscale exchange interaction evolves in macroscale correlations and ordered phases of matter, such as magnetism and superconductivity, requires to bridge the quantum and classical worlds. This monumental challenge has so far only been achieved for systems close to their thermodynamical equilibrium. Here we follow in real time the ultrafast dynamics of the macroscale magnetic order parameter triggered by the impulsive optical generation of spin excitations with the shortest possible nanometer-wavelength and femtosecond-period. Our experiments also disclose a possibility for the coherent control of these femtosecond nanomagnons, which are defined by the exchange energy. These findings open up novel opportunities for fundamental research on the role of short-wavelength spin excitations in magnetism and high-temperature superconductivity, since they provide a macroscopic probe of the femtosecond dynamics of sub-nanometer spin-spin correlations and, ultimately, of the exchange energy. With this approach it becomes possible to trace the dynamics of such short-range magnetic correlations for instance during phase transitions. Moreover, our work suggests that nanospintronics and nanomagnonics can employ phase-controllable spin waves with frequencies in the 20 THz domain.

First experimental evidence of the population of the first 2- state in 16C above the neutron threshold is obtained by neutron knockout from 17C on a hydrogen target. The invariant mass method combined with in-beam gamma-ray detection is used to locate the state at 5.45(1) MeV. Comparison of its populating cross section and parallel momentum distribution with a Glauber model calculation utilizing the shell-model spectroscopic factor confirms the core-neutron removal nature of this state. Additionally, a previously known unbound state at 6.11 MeV and a new state at 6.28(2) MeV are observed. The position of the first 2- state, which belongs to a member of the lowest-lying p-sd cross shell transition, is reasonably well described by the shell-model calculation using the WBT interaction., Comment: 15 pages, 3 figures

Magneto-caloric effects (MCEs) measurement system in adiabatic condition is proposed to investigate the thermodynamic properties in pulsed magnetic fields up to 55 T. With taking the advantage of the fast field- sweep rate in pulsed field, adiabatic measurements of MCEs were carried out at various temperatures. To obtain the prompt response of the thermometer in the pulsed field, a thin film thermometer is grown directly on the sample surfaces. The validity of the present setup was demonstrated in the wide temperature range through the measurements on Gd at about room temperature and on Gd3Ga5O12 at low temperatures. The both results show reasonable agreement with the data reported earlier. By comparing the MCE data with the specific heat data, we could estimate the entropy as functions of magnetic field and temperature. The results demonstrate the possibility that our approach can trace the change in transition temperature caused by the external field., Comment: 7 pages, 7 figures, Submitted to Review of Scientific Instruments

The microlensing event OGLE-2008-BLG-510 is characterised by an evident asymmetric shape of the peak, promptly detected by the ARTEMiS system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrates that: 1) automated real-time detection of weak microlensing anomalies with immediate feedback is feasible, efficient, and sensitive, 2) rather common weak features intrinsically come with ambiguities that are not easily resolved from photometric light curves, 3) a modelling approach that finds all features of parameter space rather than just the `favourite model' is required, and 4) the data quality is most crucial, where systematics can be confused with real features, in particular small higher-order effects such as orbital motion signatures. It moreover becomes apparent that events with weak signatures are a silver mine for statistical studies, although not easy to exploit. Clues about the apparent paucity of both brown-dwarf companions and binary-source microlensing events might hide here., Comment: 17 pages with 8 figures, MNRAS submitted

The vector analyzing power has been measured for the elastic scattering of neutron-rich 6He from polarized protons at 71 MeV/nucleon making use of a newly constructed solid polarized proton target operated in a low magnetic field and at high temperature. Two approaches based on local one-body potentials were applied to investigate the spin-orbit interaction between a proton and a 6He nucleus. An optical model analysis revealed that the spin-orbit potential for 6He is characterized by a shallow and long-ranged shape compared with the global systematics of stable nuclei. A semimicroscopic analysis with a alpha+n+n cluster folding model suggests that the interaction between a proton and the alpha core is essentially important in describing the p+6He elastic scattering. The data are also compared with fully microscopic analyses using non-local optical potentials based on nucleon-nucleon g-matrices., Comment: 20 pages, 20 figures, accepted by Physical Review C

A Gamow-Teller (GT) transition from the drip-line nucleus 14Be to 14B was studied via the (p,n) reaction in inverse kinematics using a secondary 14Be beam at 69 MeV/nucleon. The invariant mass method is employed to reconstruct the energy spectrum. A peak is observed at an excitation energy of 1.27(2) MeV in 14B, together with bumps at 2.08 and 4.06(5) MeV. The observed forward peaking of the state at 1.27 MeV and a good description for the differential cross section, obtained with a DWBA calculation provide support for the 1+ assignment to this state. By extrapolating the cross section to zero momentum transfer the GT-transition strength is deduced. The value is found to compare well with that reported in a beta-delayed neutron emission study., Comment: 5 pages, 2 figures

Vector analyzing power for the proton-6He elastic scattering at 71 MeV/nucleon has been measured for the first time, with a newly developed polarized proton solid target working at low magnetic field of 0.09 T. The results are found to be incompatible with a t-matrix folding model prediction. Comparisons of the data with g-matrix folding analyses clearly show that the vector analyzing power is sensitive to the nuclear structure model used in the reaction analysis. The alpha-core distribution in 6He is suggested to be a possible key to understand the nuclear structure sensitivity., Comment: 5 pages, 3 figures, accepted for publication as a Rapid Communication in Physical Review C

Liquid xenon is a suitable material for a dark matter search. For future large scale experiments, single phase detectors are attractive due to their simple configuration and scalability. However, in order to reduce backgrounds, they need to fully rely on liquid xenon's self-shielding property. A prototype detector was developed at Kamioka Observatory to establish vertex and energy reconstruction methods and to demonstrate the self-shielding power against gamma rays from outside of the detector. Sufficient self-shielding power for future experiments was obtained., Comment: 8 pages, 8 figures

We carried out observations, with five different instruments ranging in aperture from 0.4m to 10m, of the satellites of Uranus during that planet's 2007 Equinox. Our observations covered specific intervals of time when mutual eclipses and occultations were predicted. The observations were carried out in the near-infrared part of the spectrum to mitigate the glare from the planet. Frames were acquired at rates > 1/min. Following modelling and subtraction of the planetary source from these frames, differential aperture photometry was carried out on the satellite pairs involved in the predicted events. In all cases but one, nearby bright satellites were used as reference sources. We have obtained fifteen individual lightcurves, eight of which show a clear drop in the flux from the satellite pair, indicating that a mutual event took place. Three of these involve the faint satellite Miranda. All eight lightcurves were model-fitted to yield best estimates of the time of maximum flux drop and the impact parameter. In three cases best-fit albedo ratios were also derived. We used these estimates to generate intersatellite astrometric positions with typical formal uncertainties of <0.01 arcsec, several times better than conventional astrometry of these satellites. The statistics of our estimated event midtimes show a systematic lag, with the observations later than predictions. In addition, lightcurves of two partial eclipses of Miranda show no statistically significant evidence of a light drop, at variance with the predictions. These indicate that new information about the Uranian satellite system is contained in observations of mutual events acquired here and by other groups., Comment: 8 pages, 3 figures, accepted for publication in Astronomy and Astrophysics Uses aa style package

We report the discovery of the first symbiotic star (V=21.6, K_S=15.8 mag) in the Local Group dwarf irregular galaxy NGC6822. This star was identified during a spectral survey of Ha emission-line objects using the Southern African Large Telescope (SALT) during its performance-verification phase. The observed strong emission lines of HI and HeII suggest a high electron density and T* < 130 000 K for the hot companion. The infrared colours allow us to classify this object as an S-type symbiotic star, comprising a red giant losing mass to a compact companion. The red giant is an AGB carbon star, and a semi-regular variable, pulsating in the first overtone with a period of 142 days. Its bolometric magnitude is M_bol=-4.4 mag. We review what is known about the luminosities of extragalactic symbiotic stars, showing that most, possibly all, contain AGB stars. We suggest that a much larger fraction of Galactic symbiotic stars may contain AGB stars than was previously realised., Comment: 6 pages, 4 figures, accepted to MNRAS

We report dynamic control of magnetization precession by light alone. A ferromagnetic (Ga,Mn)As epilayer was used for experiments. Amplitude of precession was modulated to a large extent by tuning the time interval between two successive optical pump pulses which induced torques on magnetization through a non-thermal process. Nonlinear effect in precession motion was also discussed., Comment: 3 pages, 4 figures, Submitted to APL

We aim to understand the multi-wavelength properties of 2XMM J123204+215255, the source with the most extreme X-ray-to-optical flux ratio amongst a sample of bright X-ray selected EXOs drawn from a cross-correlation of the 2XMMp catalogue with the SDSS-DR5 catalogue. We use 2XMMp X-ray data, SDSS-DR5, NOT and UKIRT optical/NIR photometric data and Subaru MOIRCS IR spectroscopy to study the properties of 2XMM J123204+215255. We created a model SED including an obscured QSO and the host galaxy component to constrain the optical/IR extinction and the relative contribution of the AGN and the galaxy to the total emission. 2XMM J123204+215255 is a bright X-ray source with f_X~10^{-12} erg cm^{-2} s^{-1} (2-10 keV energy band) which has no detection down to a magnitude i' > 25.2. NIR imaging reveals a faint K-band counterpart and NIR spectroscopy shows a single broad (FWHM=5300 km/s) emission line, which is almost certainly H-alpha at z=1.87. The X-ray spectrum shows evidence of significant absorption (N_H > 10^{23} cm^{-2}), typical of type 2 AGN, but the broad H-alpha emission suggests a type 1 AGN classification. The very red optical/NIR colours (i'-K > 5.3) strongly suggest significant reddening however. We find that simple modelling can successfully reproduce the NIR continuum and strongly constrain the intrinsic nuclear optical/IR extinction to A_V~4, which turns out to be much smaller than the expected from the X-ray absorption (assuming Galactic gas-to-dust ratio)., Comment: 7 pages, 5 figures. Accepted for publication in A&A

We discuss the conservation of angular momentum in nuclear time-dependent Hartree-Fock calculations for a numerical representation of wave functions and potentials on a three-dimensional cartesian grid. Free rotation of a deformed nucleus performs extremely well even for relatively coarse spatial grids. Heavy ion collisions produce a highly excited compound system associated with substantial nucleon emission. These emitted nucleons reach the bounds of the numerical box which leads to a decrease of angular momentum. We discuss strategies to distinguish the physically justified loss from numerical artifacts., Comment: 4 pages

The neutron-rich carbon isotopes 19,17C have been investigated via proton inelastic scattering on a liquid hydrogen target at 70 MeV/nucleon. The invariant mass method in inverse kinematics was employed to reconstruct the energy spectrum, in which fast neutrons and charged fragments were detected in coincidence using a neutron hodoscope and a dipole magnet system. A peak has been observed with an excitation energy of 1.46(10) MeV in 19C, while three peaks with energies of 2.20(3), 3.05(3), and 6.13(9) MeV have been observed in 17C. Deduced cross sections are compared with microscopic DWBA calculations based on p-sd shell model wave functions and modern nucleon-nucleus optical potentials. Jpi assignments are made for the four observed states as well as the ground states of both nuclei., Comment: 20 pages

Nuclear spins are polarized electrically in a breakdown regime of an odd-integer quantum Hall effect (QHE). Electron excitation to the upper Landau subband with the opposite spin polarity flips nuclear spins through the hyperfine interaction. The polarized nuclear spins reduce the spin-splitting energy and accelerate the QHE breakdown. The Knight shift of the nuclear spins is also measured by tuning electron density during the irradiation of radio-frequency magnetic fields., Comment: 3 pages, 2 figures, EP2DS-17

We present the XMM-Newton Medium sensitivity Survey (XMS), including a total of 318 X-ray sources found among the serendipitous content of 25 XMM-Newton target fields. The XMS comprises four largely overlapping source samples selected at soft (0.5-2 keV), intermediate (0.5-4.5 keV), hard (2-10 keV) and ultra-hard (4.5-7.5 keV) bands, the first three of them being flux-limited. We report on the optical identification of the XMS samples, complete to 85-95%. At the intermediate flux levels sampled by the XMS we find that the X-ray sky is largely dominated by Active Galactic Nuclei. The fraction of stars in soft X-ray selected samples is below 10%, and only a few per cent for hard selected samples. We find that the fraction of optically obscured objects in the AGN population stays constant at around 15-20% for soft and intermediate band selected X-ray sources, over 2 decades of flux. The fraction of obscured objects amongst the AGN population is larger (~35-45%) in the hard or ultra-hard selected samples, and constant across a similarly wide flux range. The distribution in X-ray-to-optical flux ratio is a strong function of the selection band, with a larger fraction of sources with high values in hard selected samples. Sources with X-ray-to-optical flux ratios in excess of 10 are dominated by obscured AGN, but with a significant contribution from unobscured AGN., Comment: A&A, accepted

(abridged) We present near-infrared (NIR) adaptive optics imaging obtained with VLT/NACO and optical spectroscopy from the Southern African Large Telescope (SALT) of a luminous infrared galaxy (LIRG) IRAS 19115-2124. These data are combined with archival HST imaging and Spitzer imaging and spectroscopy, allowing us to study this disturbed interacting/merging galaxy, dubbed the Bird, in extraordinary detail. In particular, the data reveal a triple system where the LIRG phenomenon is dominated by the smallest of the components. One nucleus is a regular barred spiral with significant rotation, while another is highly disturbed with a surface brightness distribution intermediate to that of disk and bulge systems, and hints of remaining arm/bar structure. We derive dynamical masses in the range 3-7x10^10 M_solar for both. The third component appears to be a 1-2x10^10 M_solar mass irregular galaxy. The total system exhibits HII galaxy-like optical line ratios and strengths, and no evidence for AGN activity is found from optical or mid-infrared data. The star formation rate is estimated to be 190 M_solar/yr. We search for SNe, super star clusters, and detect 100-300 km/s outflowing gas from the Bird. Overall, the Bird shows kinematic, dynamical, and emission line properties typical for cool ultra luminous IR galaxies. However, the interesting features setting it apart for future studies are its triple merger nature, and the location of its star formation peak - the strongest star formation does not come from the two major K-band nuclei, but from the third irregular component. Aided by simulations, we discuss scenarios where the irregular component is on its first high-speed encounter with the more massive components., Comment: 24 pages, 16 figures. Accepted MNRAS version, minor corrections only, references added. Higher resolution version (1.3MB) is available from http://www.saao.ac.za/~petri/bird/ulirg_bird_highres_vaisanen_v2.pdf

In this work we present the first spectroscopic results obtained with the Southern African Large Telescope (SALT) telescope during its perfomance-verification phase. We find that the Sagittarius dwarf spheroidal galaxy (Sgr) Sgr contains a youngest stellar population with [O/H] -0.2 and age t>1 Gyr, and an oldest population with [O/H]=-2.0. The values are based on spectra of two planetary nebulae (PNe), using empirical abundance determinations. We calculated abundances for O, N, Ne, Ar, S, Cl, Fe, C and He. We confirm the high abundances of PN StWr2-21 with 12+log(O/H) = 8.57+/-0.02 dex. The other PN studied, BoBn1, is an extraordinary object in that the neon abundance exceeds that of oxygen. The abundances of S, Ar and Cl in BoBn1 yield the original stellar metallicity, corresponding to 12+log(O/H) = 6.72+/-0.16 dex which is 1/110 of the solar value. The actual [O/H] is much higher: third dredge-up enriched the material by a factor of ~12 in oxygen, ~240 in nitrogen and ~70 in neon. Neon as well as nitrogen and oxygen content may have been produced in the intershell of low-mass AGB stars. Well defined broad WR lines are present in the spectrum of StWr2-21 and absent in the spectrum of BoBn1. This puts the fraction of [WR]-type central PNe stars to 67% for dSph galaxies., Comment: 14 pages, 4 figures, accepted to MNRAS