Tadayasu Dotani

Suzaku Observation of the Anomalous X-Ray Pulsar CXOU J164710.2—455216

AS uzaku TOO observation of CXOU J164710.2� 455216 was performed on 2006 September 23–24 for a net exposure of 38.8 ks. Pulsations were clearly detected in the XIS light curves with a pulse period of 10.61063(2) s. The XIS pulse profile is found to be highly non-sinusoidal. It shows 3 peaks of different amplitudes with an RMS fractional amplitude of � 11% in the 0.2–6.0 keV energy band. The 1–10 keV XIS spectra were well fitted by two different models consisting of a power-law and a blackbody component and two blackbody components, respectively. Although both the models are statistically acceptable, a difference in the pulse profiles at soft (0.2–6.0 keV) and hard (6–12 keV) X-rays favors the model consisting of two blackbody components. The temperatures of two blackbody components are found to be 0.61 ˙ 0.01 keV and 1.22 ˙ 0.06 keV, and the value of the absorption column density is 1.73 ˙ 0.03 � 10 22 atoms cm � 2 .P ulsephase resolved spectroscopy shows that the flux of the soft blackbody component consists of three narrow peaks, whereas the flux of the other component shows a single peak over the pulse period of the AXP. The blackbody radii change between 2.2–2.7 km and 0.28–0.38 km (assuming the source distance to be 5 kpc) over the pulse phases for the soft and hard components, respectively. The details of the results obtained from the timing and spectral analyses are presented.

Suzaku Observations of the Old Pulsar Wind Nebula Candidate HESS J1356-645

A largely extended X-ray emission was discovered around the pulsar PSR J1357-6429 with the Suzaku deep observations. The pulsar, whose characteristic age is 7.3 kyr, is located within the TeV gamma-ray source HESS J1356-645. The extended emission is found to have a 1sigma X-ray size of ~4 arcmin, or ~3 pc at 2.4 kpc, with a small offset from the pulsar. Its X-ray spectrum is well reproduced by a simple power-law model with a photon index of 1.70+0.07-0.06. No significant spatial variation was found for the X-ray photon index as a function of distance from the pulsar. We conclude that the extended emission is associated to the pulsar wind nebula of PSR J1357-6429. This is a new sample of largely extended nebulae around middle-aged pulsars. We discuss the evolution of this PWN according to the relic PWN scenario.

High-speed on-board data processing for x-ray CCD camera

We have developed a novel architecture to process 2-dimensional digital image data with very high speed. The architecture is realized with an FPGA to extract only the X-ray signals from the raw frame data of an X-ray CCD for an astronomical use. The circuit scale is small enough to be implemented in an FPGA currently available for a space use, while the data processing speed of 107 pixels/sec is achieved. The architecture can be adapted in principle to a wide range of applications.

The optical design and physical optics analysis of a cross-Dragonian telescope for LiteBIRD

The Lite satellite for the studies of B-mode polarization and Inflation from the cosmic microwave background (CMB) Radiation Detection (LiteBIRD) is a next generation CMB satellite dedicated to probing the inflationary universe. It has two telescopes, Low Frequency Telescope (LFT) and High Frequency Telescope (HFT) to cover wide observational bands from 34 GHz to 448 GHz. In this presentation, we report the optical design and characterization of the LFT. We have used the CODE-V to obtain the LFT optical design based on a cross- Dragonian telescope. It is an image-space telecentric system with an F number of 3.5 and 20 x 10 degrees2 field of view. The main, near and far side lobes at far-field have been calculated by using a combination of HFSS and GRASP 10. It is revealed that the LFT telescope has good main lobe properties to satisfy the requirements. On the other hand, the side lobes are affected by the stray light that stems from the triple reflection and the direct path from feed. In order to avoid the stray light, the way to block these paths is now under study.

Current design of the electrical architecture for the payload module of LiteBIRD

LiteBIRD is a space-borne project for mapping the anisotropy of the linear polarization of the cosmic microwave background (CMB). The project aims to measure the B-mode pattern in a large angular scale to test the cosmic inflation theory. It is currently in the design phase lead by an international team of Japan, US, Canada, and Europe. We report the current status of the design of the electrical architecture of the payload module of the satellite, which is based on the heritages of other cryogenic space science missions using bolometers or microcalorimeters.

The ASCA Results of Gro J1744–28

We present the ASCA/GIS results of the transient source GRO J1744-28, the bursting X-ray pulsar, for the two times observations about one year apart. (the first and the second observations are on Feb. 27th 1996 and Mar. l6th 1997 respectively.) Since the discovery of GRO J1744-28 on Dec. 2 1995 with the BATSE observatory (Fishman et al. 1995; Kouveliotou et al.), thousands of Type II X-ray bursts, and sinusoidal pulsations have been observed in the X-ray band. No other source has ever been found to exhibit such unusual characteristics. Following each burst the flux decreases below, and recovers to the pre-burst persistent level (here after the dip) within a few seconds to a few minutes, depending on the total flux of the burst. We examined the spectrum of GRO J1744-28 during each persistent, dip, burst phases at the two observations. This is the first detail study of the spectra (l-10keV band) of GRO J1744-28.