592 research outputs found

    A Super Bubble Candidate in the Galactic Center and a Local Enhancement G359.77-0.09

    Full text link
    A 20' \times 16' elliptical ring-like structure has been found near the Galactic center in the narrow energy band corresponding to the Kα\alpha line from He-like sulfur. In the ring, two diffuse sources are found, a supernova remnant candidate G359.79-0.26 and an unidentified source G359.77-0.09. The X-ray spectrum of G359.77-0.09 is similar to that of G359.79-0.26, which can be explained by an absorbed thin thermal plasma model with temperatures of 0.7 and 1.0 keV. The absorption column densities of these two sources are large (N_H = 6.9 \times 10^{22} and 4.5 \times 10^{22} cm^{-2}) and are consistent with that of the Galactic center distance. The X-ray spectrum extracted from the ring-like structure is also represented by an absorbed thin thermal plasma model (kT_e \sim 0.9 keV). The thermal energy of the plasma filling the ring-like structure is estimated to be 1.0 \times 10^{51} erg. We therefore propose that the two sources comprise a single ring-like object, which is possibly a super bubble with a size of 49 pc \times 40 pc in the Galactic center region.Comment: 9 pages, 7 figures, accepted for publication in PAS

    An Apparent Hard X-ray Decline of CH Cygni

    Get PDF
    CH Cygni is a symbiotic star consisting of an M giant and an accreting white dwarf, which is known to be a highly variable X-ray source with a complex, two-component, spectra. Here we report on two Suzaku observations of CH Cyg, taken in 2006 January and May, during which the system was seen to be in a soft X-ray bright, hard X-ray faint state. Based on the extraordinary strength of the 6.4 keV fluorescent Fe K-alpha line, we show that the hard X-rays observed with Suzaku are dominated by scattering.Comment: 8 pages, 4 figures, accepted by Publications of the Astronomical Society of Japa

    Effect of 1,2-Dimethylhydrazine and Hydrogen Peroxide for the Duodenal Tumorigenesis in Relation to Blood Catalase Activity in Mice

    Get PDF
    Three different mouse strains, C3H/C^b_s C3H/HeN and B6C3 (C57BL x C3H) F1, having low, high and moderate catalase activities, were studied for duodenal tumorigenesis by the combined treatment with 1,2-dimethylhydrazine (DMH)* and hydrogen peroxide (HPO). DMH alone rarely induced duodenal tumors. Administration of HPO into 3 different mouse strains induced different frequencies of duodenal tumors ; 91.7% in C3H/C^b_s 9.5% in C3H/HeN and 31.8% in B6C3F1 mice. The incidence of duodenal tumors was significantly increased to 52.6% and 93.8% both in C3H/HeN and B6C3F1 mice by the combined administration of DMH and HPO. These increases in duodenal tumor were inversely correlated with the finding that administration of DMH or HPO alone or combined treatment of DMH and HPO significantly decreased mean blood catalase activities both in C3H and B6C3F1 mice

    Gravitational Redshift Detection from the Magnetic White Dwarf Harbored in RX J1712.6-2414

    Full text link
    Gravitational redshift is a fundamental parameter that allows us to determine the mass-to-radius ratio of compact stellar objects, such as black holes, neutron stars, and white dwarfs (WDs). In the X-ray spectra of the close binary system, RX J1712.6−-2414, obtained from the Chandra High-Energy Transmission Grating observation, we detected significant redshifts for characteristic X-rays emitted from hydrogen-like magnesium, silicon (ΔE/Erest∼7×10−4\Delta E/E_{\rm rest} \sim 7 \times 10^{-4}), and sulfur (ΔE/Erest∼15×10−4\Delta E/E_{\rm rest} \sim 15 \times 10^{-4}) ions, which are over the instrumental absolute energy accuracy (ΔE/Erest∼3.3×10−4{\Delta E/E_{\rm rest} \sim 3.3} \times 10^{-4}). Considering some possible factors, such as Doppler shifts associated with the plasma flow, systemic velocity, and optical depth, we concluded that the major contributor to the observed redshift is the gravitational redshift of the WD harbored in the binary system, which is the first gravitational redshift detection from a magnetic WD. Moreover, the gravitational redshift provides us with a new method of the WD mass measurement by invoking the plasma-flow theory with strong magnetic fields in close binaries. Regardless of large uncertainty, our new method estimated the WD mass to be MWD>0.9 M⊙M_{\rm WD}> 0.9\,M_{\odot}.Comment: 13 pages, 5 figures. Accepted for publication in Ap

    Real-time Motion Generation and Data Augmentation for Grasping Moving Objects with Dynamic Speed and Position Changes

    Full text link
    While deep learning enables real robots to perform complex tasks had been difficult to implement in the past, the challenge is the enormous amount of trial-and-error and motion teaching in a real environment. The manipulation of moving objects, due to their dynamic properties, requires learning a wide range of factors such as the object's position, movement speed, and grasping timing. We propose a data augmentation method for enabling a robot to grasp moving objects with different speeds and grasping timings at low cost. Specifically, the robot is taught to grasp an object moving at low speed using teleoperation, and multiple data with different speeds and grasping timings are generated by down-sampling and padding the robot sensor data in the time-series direction. By learning multiple sensor data in a time series, the robot can generate motions while adjusting the grasping timing for unlearned movement speeds and sudden speed changes. We have shown using a real robot that this data augmentation method facilitates learning the relationship between object position and velocity and enables the robot to perform robust grasping motions for unlearned positions and objects with dynamically changing positions and velocities
    • …
    corecore