Masahiro Tsujimoto

The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido JapanWe report current status of the timing calibration of the X-ray Imaging Spectrometer (XIS) on board Suzaku. The XIS is designed to be flexible enough and can be operated in various clocking modes. Since the absolute timing accuracy of the Hard X-ray Detector (HXD) was calibrated to be better than 360 microseconds, we calibrated the XIS timing accuracy referring to the HXD data. We employed Hercules X-1 and Cygnus X-1 for the calibration taking into account of the energy dependence of their time variations. We found no significant offset in the XIS time assignment in the normal mode (with burst/window options), whereas a marginal offset of 30 +/- 16 ms was found in the Parallel-Sum mode.Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of Science

The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido JapanWe report the XIS calibration on the data taken with the 2 x 2 mode and window option and the current status of the XIS Non-X-ray Background (NXB) database. The 2 x 2 mode and window option are useful for bright source observations to avoid telemetry saturation and event pile-up. The NXB database provides the best-estimated NXB spectrum for any specific observations obtained with the standard mode (Normal-Clock with no Window or Burst and 5 x 5(sub -) (3 x 3(sub -) Editing mode). The data taken with the 2 x 2 mode in the "SCI-off" era are fully calibrated, and there is no practical difference from those taken with the standard mode. A calibration study for the data taken with the 2 x 2 mode in the "SCI-on" era is on-going. The calibration for the data taken with the window option was significantly improved in the HEASOFT 6.6.2 released at 2009 April 1st. In the comparison with the standard-mode data, the gain difference around 6 keV becomes less than 10 and 15 eV in XIS 0,3 and XIS 1, respectively. We have been updating the NXB database every half a year. There is no drastic change in the light curves, but steady approximately 4 % year(sup -1) level increase and decrease are found in those of XIS 0,3 and XIS 1, respectively.Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of ScienceNumber of authors: 25

Protostars, the first stage of stellar evolution, are born in a dense core of a molecular cloud with temperature of about 10 K. X-rays can be emitted from a high temperature plasma of 10^6-10^8K, hence may not be expected from protostars. Nature, however, is much more imaginative than we are. The Japanese X-ray satellite ASCA found X-rays from a few protostars. The US satellite Chandra successively found that X-rays are common in most of the young stars. Many protostars show flare-like events similar to our sun, hence the X-rays are attributable to solar type magnetic activities. The X-ray work should finally lead to our deep understanding of the evolution and structure of young stars and planets. This paper overviews the pioneering results in the unique waveband, the X-ray.