Relativistic Spectra of Hot Black-Hole Winds

We examine hybrid thermal-nonthermal synchrotron spectra from a spherically symmetric, optically-thin wind, taking into account the relativistic effect. In the relativistic flow from the central object, due to the relativistic beaming effect, the observed spectra often shift towards high frequency and high intensity directions. In the optically thin outflows, however, we find that the intensity of the observed spectra decreases compared with that of the emitted ones, although the peak frequency shifts towards the high frequency direction. This is because in the optically thin outflows we can see the far side flows that go away from the observer. We thus carefully consider optically thin relativistic flows around a black hole such as Sgr A$^*$.Comment: 7pages, 6 figures, Accepted for publication in PAS

Memorial: The lost giant in Japan, Kyojiro Someya (1923-2000); Lost giant in Japan, Kyojiro Someya (1923-2000)

Kyojiro Someya, Professor emeritus of Waseda University, died suddenly before dawn on January 3, 2000, as he neared the age of 77. He had completed the correction of proofs of his last book, Accounting and Management of Cash Flow, on the day before, but to our regret could not write the preface. His academic achievements were his brilliant activities at home and abroad and his publication of over 90 books, including 24 coauthored, and more than 200 papers