A radio burst lasting up to 72 hr at a high Galactic latitude was detected by interferometric drift-scanning observation using an eight-element, 20 m diameter fixed spherical dish array at the Waseda Nasu Pulsar Observatory in Japan.

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We present the results of the simultaneous observation of the giant radio pulses (GRPs) from the Crab pulsar at 0.3, 1.6, 2.2, 6.7, and 8.4 GHz with four telescopes in Japan. We obtain 3194 and 272 GRPs occurring at the main pulse and the interpulse phases, respectively. A few GRPs detected at both 0.3 and 8.4 GHz are the most wide-band samples ever reported. In the frequency range from 0.3 to 2.2 GHz, we find that about 70% or more of the GRP spectra are consistent with single power laws and the spectral indices of them are distributed from −4 to −1. We also find that a significant number of GRPs have such a hard spectral index (approximately −1) that the fluence at 0.3 GHz is below the detection limit ("dim-hard" GRPs). Stacking light curves of such dim-hard GRPs at 0.3 GHz, we detect consistent enhancement compared to the off-GRP light curve. Our samples show apparent correlations between the fluences and the spectral hardness, which indicates that more energetic GRPs tend to show softer spectra. Our comprehensive studies on the GRP spectra are useful materials to verify the GRP model of fast radio bursts in future observations.

We report the detection of two radio transients in the Nasu 1.4 GHz wide-field survey. In the survey, we use four pairs of the two-element interferometer aligned east-west to monitor the wide-field sky and simultaneously survey the region at þ32 < < þ42 in drift scanning. In 27 days of continuous observation at a declination between +41 and +42 , we have detected two radio transients of 1 Jy intensity. Since they appeared on only a single day during the 27 days, we consider these detections to be 1 Jy class bursts that brightened and faded within 2 days and have constant emission smaller than 200 mJy, the detection limit of the 27 days of integrated data. While one transient was in low Galactic latitudes, the other transient was detected in high Galactic latitudes and has counterparts only in -ray databases. Therefore, the high Galactic latitude transient might be one of the active galactic nuclei that are normally very faint in X-ray and quiet in radio wavelengths.