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All-sky observations from hard X-ray to soft gamma-ray band is very important to study non-thermal processes for many bright astronomical objects such as Gamma-ray Bursts (GRBs), soft gamma-ray repeaters (SGRs), and solar flares. The Wide-band All-sky Monitor (WAM) onboard Suzaku enables unique observations utilizing its wide energy coverage between 50 keV to 5000 keV with very large effective area of 400 cm2 even at 1 MeV. After six year observations, the WAM has detected more than 850 GRBs. Thanks to its largest effective area above 300 keV among all all-sky instruments, many data with good photon statistics is available even for both timeresolved spectroscopy and short duration GRBs and some implications for emission mechanism and physical condition of emission region of GRBs have been suggested. The WAM also observed many solar flares and SGRs. We summarized the observational results from 105 solar flares and their characteristics and addressed discussion on particle acceleration and heating process in solar flares. In addition to above transient objects, many bright gamma-ray sources such as Crab, Cyg X-1, GRB 1915-105, and NGC 4541 are monitored by the WAM using earth occultation technique. [ABSTRACT FROM AUTHOR]

A result of a joint timing analysis is presented for prompt emission of long-duration (T90 = 81 s) GRB 090709A with Swift Burst Alert Telescope (Swift/BAT), Suzaku Wide-band All-sky Monitor (Suzaku/WAM) and Konus-Wind over an energy range from 15 keV to 5 MeV. It was reported that multi-peaked GRB 090709A exhibited a possible periodic behavior with a period of about 8 s which is comparable to typical time scale of soft gamma-ray repeaters. However, the periodicity is still marginal in detailed analysis with Swift/BAT and GRB090709A exhibited a typical afterglow[1] [2]. To investigate significance of the periodicity more quantitatively, we performed a detailed timing analysis on all the lightcurves obtained with Suzaku/WAM, Swift/BAT, and Konus-Wind evaluating their underlying trend, red noise and white noise. [ABSTRACT FROM AUTHOR]

Although the afterglow observations in HETE-2 and Swift era have revealed a lot of afterglow properties of gamma-ray bursts (GRBs), we still have poor understanding of the prompt gamma-ray emission, such as the emission mechanism of the prompt emission and differences between short and long duration GRBs. We have observed many prompt emission of GRBs by Suzaku Wide-band All-sky Monitor in wide energy range of 50–5000 keV, with very large effective area of 400 cm2 even at 1 MeV. Furthermore, a combination of the Suzaku/WAM and Swift data provides us not only wider energy range of 15–5000 keV but also redshift information even for some short GRBs. Thanks to these information, we can firstly investigate an intrinsic correlation for short GRBs like Epeak-Liso relation, and we can derive the same type of relation for time-resolved spectra of long GRBs in finer time-scale with higher statistics than ever before. These results could be used to discuss the differences between short and long GRBs, and our time-resolved Epeak-Liso relation also could be used as both more appropriate redshift indicator and new probe of the fireball dynamics. [ABSTRACT FROM AUTHOR]

The Wide-Field Telescope for Gamma-ray burst (GRB) Early Timing (WIDGET) is a robotic telescope aiming to observe the optical emission associated with the GRB. The system has a 64°×64° wide field-of-view and tracks the Swift/BAT field-of-view automatically. The WIDGET had been operated at Akeno campus of the Institute for Cosmic Ray Research of the University of Tokyo through May 2004 to October 2006, and has been moved to Kiso observatory, IoA, University of Tokyo. For two years in Akeno, the WIDGET succeeded to observe the GRB position seven times simultaneously with the HETE2 or Swift. Based on the successful operation in Akeno, we have moved and improved the system to Kiso observatory to realize more sensitive and efficient observation. These major improvements have been carried out until March 2007 and we have succeeded to reduce the background and achieved the limiting magnitude of Mv = 11–12 after color correction. [ABSTRACT FROM AUTHOR]