Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

Japan Transformed : Political Change and Economic Restructuring : [book review]

Non UBCUnreviewedUnknow

Political economy of Japan : Growth, Challenges and Prospects for a Well-Being Nation : [book review]

Non UBCUnreviewedUnknow

The Fukushima Disaster and Japan’s Nuclear Plant Vulnerability in Comparative Perspective

We consider the vulnerability of nuclear power plants to a disaster like the one that occurred at Fukushima Daiichi. Examination of Japanese nuclear plants affected by the earthquake and tsunami on March 11, 2011 shows that three variables were crucial at the early stages of the crisis: plant elevation, sea wall elevation, and location and status of backup generators. Higher elevations for these variables, or waterproof protection of backup generators, could have mitigated or prevented the disaster. We collected information on these variables, along with historical data on run-up heights, for 89 coastal nuclear power plants in the world. The data shows that 1. Japanese plants were relatively unprotected against potential inundation in international comparison, but there was considerable variation for power plants within and outside of Japan; 2. Older power plants and plants owned by the largest utility companies appear to have been particularly unprotected