Suzaku View of the Supernova Remnant RCW 86: X-Ray Studies of Newly-Discovered Fe-Rich Ejecta

We report on results of imaging and spectral analysis of the supernova remnant (SNR) RCW 86 observed with Suzaku. The SNR is known to exhibit K-shell emission of low ionized Fe, possibly originating from supernova ejecta. We revealed the global distribution of the Fe-rich plasma in the entire remnant, for the first time; the Fe-K emission was clearly detected from the west, north, and south regions, in addition to the X-ray brighter shells of southwest and northeast, where the presence of the Fe-rich ejecta has already been reported. The spectrum of each region is well represented by a three-component model consisting of low- and high-temperature thermal plasmas and a non-thermal emission. The lower-temperature component, with elemental abundances of near the solar values, likely originates from the forward shocked interstellar medium, while the Fe-rich ejecta is described by the hotter plasma. From the morphologies of the forward and reverse shocks in the west region, the total ejecta mass is estimated to be 1-2M_sun for the typical explosion energy of ~ 1 x 10^{51} erg. The integrated flux of the Fe-K emission from the entire SNR roughly corresponds to a total Fe mass of about 1M_sun. Both of these estimates suggest a Type Ia supernova origin of this SNR. We also find possible evidence of an Fe-rich clump located beyond the forward-shock front in the north rim, which is reminiscent of ejecta knots observed in the Tycho and Vela SNRs.Comment: Published by PAS

Asymmetric Ejecta Distribution in SN 1006

We present the results from deep X-ray observations (~400 ks in total) of SN 1006 by the X-ray astronomy satellite Suzaku. The thermal spectrum from the entire supernova remnant (SNR) exhibits prominent emission lines of O, Ne, Mg, Si, S, Ar, Ca, and Fe. The observed abundance pattern in the ejecta components is in good agreement with that predicted by a standard model of Type Ia supernovae (SNe). The spatially resolved analysis reveals that the distribution of the O-burning and incomplete Si-burning products (Si, S, and Ar) is asymmetric, while that of the C-burning products (O, Ne, and Mg) is relatively uniform in the SNR interior. The peak position of the former is clearly shifted by 5' (~3.2 pc at a distance of 2.2 kpc) to the southeast from the SNR's geometric center. Using the SNR age of ~1000 yr, we constrain the velocity asymmetry (in projection) of ejecta to be ~3100 km/s. The abundance of Fe is also significantly higher in the southeast region than in the northwest region. Given that the non-uniformity is observed only among the heavier elements (Si through Fe), we argue that SN 1006 originates from an asymmetric explosion, as is expected from recent multi-dimensional simulations of Type Ia SNe, although we cannot eliminate the possibility that an inhomogeneous ambient medium induced the apparent non-uniformity. Possible evidence for the Cr K-shell line and line broadening in the Fe K-shell emission is also found.Comment: 11 pages, 12 figures, 4 tables, formatted using emulateapj.cls. Accepted for publication in Ap

N49: the first robust discovery of a recombining plasma in an extra galactic supernova remnant

Recent discoveries of recombining plasmas (RPs) in supernova remnants (SNRs) have dramatically changed our understanding of SNR evolution. To date, a dozen of RP SNRs have been identified in the Galaxy. Here we present Suzaku deep observations of four SNRs in the Large Magellanic Cloud (LMC), N49, N49B, N23, and DEM L71, for accurate determination of their plasma state. Our uniform analysis reveals that only N49 is in the recombining state among them, which is the first robust discovery of a RP from an extra-galactic SNR. Given that RPs have been identified only in core-collapse SNRs, our result strongly suggests a massive star origin of this SNR. On the other hand, no clear evidence for a RP is confirmed in N23, from which detection of recombination lines and continua was previously claimed. Comparing the physical properties of the RP SNRs identified so far, we find that all of them are categorized into the "mixed-morphology" class and interacting with surrounding molecular clouds. This might be a key to solve formation mechanisms of the RPs.Comment: 8 pages, 4 figures, Accepted for publication in Ap

Quantization of scalar perturbations in brane-world inflation

We consider a quantization of scalar perturbations about a de Sitter brane in a 5-dimensional anti-de Sitter (AdS) bulk spacetime. We first derive the second order action for a master variable $\Omega$ for 5-dimensional gravitational perturbations. For a vacuum brane, there is a continuum of normalizable Kaluza-Klein (KK) modes with $m>3H/2$. There is also a light radion mode with $m=\sqrt{2}H$ which satisfies the junction conditions for two branes, but is non-normalizable for a single brane model. We perform the quantization of these bulk perturbations and calculate the effective energy density of the projected Weyl tensor on the barne. If there is a test scalar field perturbation on the brane, the $m^2 = 2H^2$ mode together with the zero-mode and an infinite ladder of discrete tachyonic modes become normalizable in a single brane model. This infinite ladder of discrete modes as well as the continuum of KK modes with $m>3H/2$ introduce corrections to the scalar field perturbations at first-order in a slow-roll expansion. We derive the second order action for the Mukhanov-Sasaki variable coupled to the bulk perturbations which is needed to perform the quantization and determine the amplitude of scalar perturbations generated during inflation on the brane.Comment: 14 page

TARGET VALUE FOR THE MAXIMUM RUN-UP SPEED OF THE LONG JUMP BASED ON THE PERFORMANCE LEVEL

This study sought to obtain target values for the maximum run-up speed of the long jump based on performance level and to propose a method to easily estimate the maximum run-up speed. Run-up speeds of 429 male and 536 female long jumps were collected by a laser beam apparatus at 50 or 100 Hz. Subjects were divided into record-based groups for each 20 cm of the jumping distance, and the data were averaged in each group. Main results were as follows: 1) Average of maximum speed in higher performance groups was larger than that for lower groups: 2) A significantly negative correlation was observed between the interval time of the last 20 m before the takeoff and the maximum speed, and the obtained good fit regression line between them (R2=0.968) will enable to estimate and evaluate jumpers’ maximum run-up speed

ANALYSIS OF THE TRANSFORMATION OF THE VELOCITY OF THE CENTER OF GRAVITY IN RUNNING SINGLE LEG HORIZONTAL JUMP

The purpose of this study was to analyze the transformation of the center of gravity (CG) in the running single leg horizontal jump and to investigate the influence of the forward rotation of the takeoff leg in achieving vertical CG velocity. The subjects were 98 male long jumpers, whose mean best official jump among their recorded trials was 7.16 ± 0.66 m. Their takeoff motion was videotaped with two high-speed cameras. Horizontal CG velocity at touchdown and vertical CG velocity at toe-off had significantly positive correlations with jumping distance; the decrease in horizontal CG velocity during the takeoff phase was significantly and negatively correlated with jumping distance. Forward rotation of the spring-mass model did not contribute to an increase in vertical CG velocity, although it did contribute to an increase in horizontal CG velocity just before toe-off

Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and Its Implications

We present deep observations of the Galactic supernova remnant IC 443 with the {\it Suzaku X-ray satellite}. We find prominent K-shell lines from iron and nickel, together with a triangle residual at 8--10~keV, which corresponds to the energy of the radiative recombination continuum (RRC) of He-like iron. In addition, the wavy residuals have been seen at $\sim$5.1 and $\sim$5.5~keV. We confirm that the residuals show the first enhanced RRCs of He- and H-like calcium found in supernova remnants. These facts provide robust evidence for the recombining plasma. We reproduce the plasma in the 3.7--10~keV band using a recombining plasma model at the electron temperature 0.65~keV. The recombination parameter $n_{\rm e}t$ ($n_{\rm e}$ is electron density and $t$ is elapsed time after formation of a recombining plasma) and abundances of iron and nickel are strongly correlated, and hence the errors are large. On the other hand, the ratio of nickel to iron relative to the solar abundances is well constrained to 11$^{+4}_{-3}$ (1$\sigma$). A possibility is that the large abundance ratio is a result of an asymmetric explosion of the progenitor star.Comment: 4 pages, 5 figures, published in Ap

BIOMECHANICAL CHARACTERISTICS OF TAKEOFF PREPARATION AND TAKEOFF MOTION IN DIFFERENT JUMPING TYPES OF ELITE MALE LONG JUMPERS

This study investigated the biomechanical characteristics of takeoff preparation and takeoff motion for different types of elite male long jumpers. The subjects were 19 elite male long jumpers whose motion from the second to the last stride to takeoff was videotaped. The subjects were classified into two horizontal type (H-type) and vertical type (V-type) jumpers, based on the mean takeoff angle. The results are summarized as follows. (1) H-type jumpers tended to keep the trunk leaning forward and to retain their horizontal center of gravity (CG) velocity during takeoff preparation and takeoff phases. (2) V-type jumpers tended to extend the knee joint of the takeoff leg significantly at the touchdown of the takeoff phase and to obtain large vertical CG velocity by forward rotation of the body during the first half of the takeoff phase

THE TAKEOFF PREPARATION AND TAKEOFF MOTIONS FOR ELITE MALE LONG JUMPERS

The purpose of this study was to identify biomechanical characteristics of takeoff preparation and takeoff motions for elite male long jumpers, classifying their motions by using cluster analysis. The takeoff preparation and takeoff motions of 29 elite male long jumpers in competition were videotaped. The 29 jumps were classified into 4 jumping types with respect to the takeoff angle by using Ward’s method of cluster analysis: horizontal (H-type), semi-horizontal (SH-type), semi-vertical (SV-type), and vertical type (V-type). The H-type and SH-type jumpers maintained a large horizontal CG velocity with the trunk leaning forward in the takeoff preparation. The V-type and SV-type jumpers obtained larger vertical CG velocity by pivoting the body over the takeoff foot during the takeoff phase