تقرير
Time Variations in the Flux Density of Sgr A* at 230 GHz Detected with ALMA
| العنوان: | Time Variations in the Flux Density of Sgr A* at 230 GHz Detected with ALMA |
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| المؤلفون: | Iwata, Yuhei, Oka, Tomoharu, Tsuboi, Masato, Miyoshi, Makoto, Takekawa, Shunya |
| سنة النشر: | 2020 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies |
| الوصف: | A radio source at the Galactic center Sgr A* is a prime supermassive black hole candidate and therefore key to developing our understanding of them. Time variations in the 230 GHz band flux of Sgr A* have been found with the Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 5 observations. Measuring the flux density of Sgr A* in 1 min snapshots at 217.5, 219.5, and 234.0 GHz, we obtained light curves for ten 70 min periods. The light curves show variations at a few tens of minutes and hourly scales. The shorter timescale is similar to the orbital period of the innermost stable circular orbit around a $4\times 10^{6}$ $M_{\odot}$ black hole, suggesting that the variation originates from the immediate vicinity of Sgr A*. We also detected no time lag between 217.5 and 234.0 GHz and a dependence of the spectral index on the flux density. Comment: 8 pages, 3 figures, 1 table, accepted for publication in ApJL |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.3847/2041-8213/ab800d |
| URL الوصول: | http://arxiv.org/abs/2003.08601 |
| رقم الأكسشن: | edsarx.2003.08601 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.3847/2041-8213/ab800d |
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