11569124
Spitzer Mid-Infrared Imaging of Nearby Ultraluminous Infrared Galaxies
We have observed 14 nearby (z < 0.16) Ultraluminous Infrared Galaxies (ULIRGs) with Spitzer at 3.6-24μm. The underlying host galaxies are well-detected, in addition to the luminous nuclear cores. While the spatial resolution of Spitzer is poor, the great sensitivity of the data reveals the underlying galaxy merger remnant, and provides the first look at off-nuclear mid-infrared activity.
124130898
Study of the neutron-rich nucleus Si-36
Excited states of N=22 Si-36, populated in deep-inelastic processes produced by the interaction of a 215 MeV beam of S-36 ions with a Pb-208 target, were studied in the present work. gamma rays from the binary fragments detected using CLARA, an array of 25 Ge Clover detectors, were measured in coincidence with projectile-like fragments detected by PRISMA, a large solid angle magnetic spectrometer. Two new gamma-ray photopeaks at energies of 1442 and 842 keV were observed and tentatively assigned to the 4(+)-> 2(+) and 6(+)-> 4(+) transitions, respectively. The systematics of the level structures of N=22 isotones are presented, and a comparison is made of the behavior of Si, Mg, and S isotopes. The level structure of Si-36 is also compared with the results of sdpf shell model calculations.
119266949
MULTIBAND STUDIES OF THE OPTICAL PERIODIC MODULATION IN THE X-RAY BINARY SAX J1808.4–3658 DURING ITS QUIESCENCE AND 2008 OUTBURST
We report on time-resolved optical imaging of the X-ray binary SAX J1808.4-3658 during its quiescent state and 2008 outburst. The binary, containing an accretion-powered millisecond pulsar, has a large sinusoidal-like modulation in its quiescent optical emission. We employ a Markov chain Monte Carlo technique to fit our multi-band light curve data in quiescence with an irradiated star model, and derive a tight constraint of 50(-5)(+6) deg on the inclination angle i of the binary system. The pulsar and its companion are constrained to have masses of 0.97(-0.22)(+0.31) M-circle dot and 0.04(-0.01)(+0.02) M-circle dot (both 1 sigma ranges), respectively. The dependence of these results on the measurements of the companion's projected radial velocity is discussed. We also find that the accretion disk had nearly constant optical fluxes over a similar to 500 day period in the quiescent state our data covered, but started brightening 1.5 months before the 2008 outburst. Variations in modulation during the outburst were detected in our four observations made 7-12 days after the start of the outburst, and a sinusoidal-like modulation with 0.2 mag amplitude changed to have a smaller amplitude of 0.1 mag. The modulation variations are discussed. We estimate the albedo of the companion during its quiescence and the outburst, which was approximately 0 and 0.8 (for isotropic emission), respectively. This large difference probably provides additional evidence that the neutron star in the binary turns on as a radio pulsar in quiescence.
115875551
Cosmological Vacuum Configuration in Superstring Theories with only Three-Space Expanding
Cosmological compactification of superstring theories is studied in the field theory limit, with the quadratic Euler-Gauss-Bonnet term included in the gravitational action. We find a vacuum configuration, which is of the Robertson-Walker parameter k = -1, of three-space scale factor R (t) ~ t and of constant internal-space scale factor (R (t) — const.); otherwise, it is the same as the static Candelas-Horowitz-Stominger-Witten (CHSW) configuration. While the CHSW configuration is unstable, our three-space expanding configuration is stable against time-dependent purturbations in R3 (t) and R6 (t). These results indicate the existence of cosmological models (with the presence of matter) in superstring theories which predict, asymptotically in the limit of infinitely dilute matter, no time variation for the coupling constants in four dimensions.
2081456
Numerical solution for cosmological evolution of Newton's gravitational constant in superstring theories.
By using a computer to solve the ten-dimensional Einstein equations in superstring theories, we find that the present value for the time variation of Newton's gravitational constant is in the range of -1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ to -6 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}12}$ ${\mathrm{yr}}^{\ensuremath{-}1}$ in the case of the flat internal potential, which confirms the previous perturbative estimate.
4503009
High-Resolution Imaging of Warm and Dense Molecular Gas in the Nuclear Region of the Luminous Infrared Galaxy NGC 6240
We present ~2'' resolution CO (3-2), HCO+(4-3), and 880 μm continuum images of the luminous infrared galaxy NGC 6240 obtained at the Submillimeter Array. We find that the spatially resolved CO (3-2), HCO + (4-3), and the 880 μm emission peaks between the two nuclear components that are both known to harbor AGNs. Our large velocity gradient (LVG) analysis performed on each velocity channel suggests that the peak of the molecular gas emission traced in our observations is warm (T = 20-100 K), dense (nH2 = 105.0-105.4 cm-3), and moderately optically thin (τ = 0.2-2) in the central 1 kpc. We also find large column densities of ~1023 cm-2. Such extreme conditions are observed over ~300 km s-1 centered around the CO-derived systemic velocity. The derived molecular gas mass from the CO (3-2) emission and a CO-to-H2 conversion factor commonly used for ULIRGs is (6.9 ± 1.7) × 109 M☉, and this is consistent with the mass derived from previous CO (2-1) observations. The gas is highly turbulent in the central kpc (ΔvFWZI ~ 1175 km s-1). Furthermore, possible inflow or outflow activity is suggested from the CO (3-2) velocity distribution. We tentatively state that 3.5 × 108 M☉ of isolated CO (3-2) emission seen west of the northern disk may be associated with outflows from starburst superwinds, but the gas outflow scenario from one of the central AGN is not completely ruled out. Piecing all of the information together, the central region of NGC 6240 harbors 2 AGNs, ~1010 M☉ of molecular gas mass, 5 × 107 M☉ of dust mass, and has possible evidence of inflow and outflow activity.
9937378
A MID-INFRARED COUNTERPART TO THE MAGNETAR 1E 2259+586
We report the discovery of a 4.5μm counterpart to the anomalous X-ray pulsar (magnetar) 1E 2259+586 with 
the Spitzer Space Telescope. The mid-infrared flux density is 6.3 ± 1.0μJy at 4.5μm and <20 μJy (at 95% 
confidence) at 8μm, or 0.02% of the 2–10 keV X-ray flux (corrected for extinction). Combining our Spitzer 
measurements with previously published near-infrared data, we show that the overall infrared emission from 1E 
2259+586 is qualitatively similar to that from the magnetar 4U 0142+61. Therefore, the passive X-ray-heated dust 
disk model originally developed for 4U 0142+61 might also apply to 1E 2259+586. However, the IR data from 
this source can also be fitted by a simple power-law spectrum as might be expected from magnetospheric emission.
27335793
Intruder negative-parity states of neutron-rich Si-33
This work was supported in part by the EPSRC (UK) and by the European Union under Contract No. RII3-CT-2004-506065. Five of us (D.O., M.B., A.H., K.K., and A.P.)acknowledge financial support from the EPSRC. Z.M.W acknowledges support from ORSAS and from the University of the West of Scotland. A.J. acknowledges financial supportfrom the Spanish Ministerio de Ciencia e Innovacion under Contract Nos. FPA2007-66069 and FPA2009-13377-C02-02. Zs.D. acknowledges the financial support from OTKA Project No. K68801.
119548246
Subarcsecond Resolution Mid-Infrared Observations of Super Star Clusters in the Antennae (NGC 4038/4039)*
We present ground-based subarcsecond mid-infrared imaging and spectroscopy of young super star clusters in the overlap region of the merging galaxies NGC 4038/4039 (the Antennae) obtained with the VLT Imager and Spectrometer for mid-InfraRed (VISIR). With its unprecedented spatial resolution, VISIR begins for the first time to resolve the H II/photodissociation region complexes around the star-forming regions. In the N-band spectra of two young star clusters, unexpectedly low polycyclic aromatic hydrocarbon (PAH) emission is observed, compared to what is seen with the Infrared Space Observatory and with the Spitzer Space Telescope. We conclude that a large fraction of the PAH emission cannot be directly associated with the super star clusters but originates from an extended region of at least 215 pc radius around the clusters. In the distribution of [Ne II] 12.81 μm emission, a highly obscured cluster is discovered that does not have an optical or near-infrared counterpart.
119180823
Analysis of the $B \to K^*_0(1430), a_0(1450)$ form-factors with light-cone QCD sum rules
In this article, we take the scalar mesons $K^*_0(1430)$ and $a_0(1450)$ as the conventional two-quark states, and study the $B \to K^*_0(1430), a_0(1450)$ form-factors with the $B$-meson light-cone QCD sum rules, then take those form-factors as basic input parameters to study the semi-leptonic decays $\bar{B}^0\to a_0^+(1450)l \bar{\nu}_l $ and $B^-\to K_0^{*-}(1430)l\bar{l}$, the predictions can be confronted with the experimental data in the future.
119069538
Search for gamma-ray emission from four accreting millisecond pulsars with Fermi/LAT
We report our search for -ray emission in the energy range from 100 MeV to 300 GeV from four Accreting Millisecond Pulsars (AMPs), SAX J1808.4 3658, IGR J00291+5934, XTE J1814 338, and XTE J0929 314. The data are from four-year observations carried out by Large Area Telescope (LAT) onboard the Fermi -ray Space Telescope. The AMPs were not detected, and their -ray luminosity upper limits we obtain are 5.1 × 10 33 ergs s −1 for SAX J1808.4 3658, 2.1 × 10 33 ergs s −1 for IGR J00291+5934, 1.2 × 10 34 ergs s −1 for XTE J1814 338, and 2.2 × 10 33 ergs s −1 for XTE J0929 314. We compare our results with -ray irradiation luminosities required for producing optical modulations seen from the companions in the AMPs, which has been suggested by Takata et al. (2012), and our upper limits have excluded -ray emission as the heating source in these systems except XTE J0929 314, the upper limit of which is not deep enough. Our results also do not support the model proposed by Takata et al. (2012) that relatively strong -ray emission could arise from the outer gap of a high-mass neutron star controlled by the photon-photon pair-creation for the AMPs. Two AMPs, SAX J1808.4 3658 and IGR J00291+5934, have the measurements of their spin-down rates, and we derive the upper limits of their -ray conversion efficiencies, which are 57% and 3%, respectively. We discuss the implications to the AMP systems by comparing the efficiency upper limit values with that of 20 -ray millisecond pulsars (MSP) detected by Fermi and the newly discovered transitional MSP binary J1023+0038. Subject headings: pulsars: general – stars: neutron – binaries: close – gamma rays: stars