Waseda University Nasu telescope array is a spatial fast Fourier transform (FFT) interferometer consisting of eight linearly aligned antennas with 20 m spherical dishes. This type of interferometer was developed to survey transient radio sources with an angular resolution as high as that of a 160 m dish with a field of view as wide as that of a 20 m dish. We have been performing drift-scan-mode observations, in which the telescope scans the sky around a selected declination as the earth rotates. The black hole X-ray binary V404 Cygni underwent a new outburst in 2015 June after a quiescent period of 26 years. Because of the interest in black hole binaries, a considerable amount of data on this outburst at all wavelengths was accumulated. Using the above telescope, we had been monitoring V404 Cygni daily from one month before the X-ray outburst, and two radio flares at 1.4 GHz were detected on June 21.73 and June 26.71. The flux density and time-scale of each flare were 313+/-30 mJy and 1.50+/-0.49 days, 364+/-30 mJy and 1.70+/-0.16 days, respectively. We have also confirmed the extreme variation of radio spectra within a short period by collecting other radio data observed with several radio telescopes. Such spectral behaviors are considered to reflect the change in the opacity of the ejected blobs associated with these extreme activities in radio and X-ray. Our 1.4 GHz radio data are expected to be helpful for studying the physics of the accretion and ejection phenomena around black holes.

中文翻译：

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那须望远镜阵列在 1.4 GHz 下对 2015 年爆发期间天鹅座 V404 的观测

早稻田大学那须望远镜阵列是一种空间快速傅里叶变换 (FFT) 干涉仪，由八个线性对齐的天线和 20 m 的球形天线组成。开发这种类型的干涉仪是为了测量瞬态射电源，其角分辨率与 160 m 碟子一样高，视场与 20 m 碟子一样宽。我们一直在进行漂移扫描模式观测，其中望远镜在地球自转时围绕选定的偏角扫描天空。黑洞 X 射线双星 V404 Cygni 在经历了 26 年的静止期后，于 2015 年 6 月再次爆发。由于对黑洞双星的兴趣，在所有波长上积累了大量关于这次爆发的数据。使用上述望远镜，我们从X射线爆发前一个月开始每天监测天鹅座V404，6 月 21 日 73 日和 6 月 26 日 71 日检测到两个 1.4 GHz 无线电耀斑。每个耀斑的通量密度和时间尺度分别为 313+/-30 mJy 和 1.50+/-0.49 天、364+/-30 mJy 和 1.70+/-0.16 天。我们还通过收集其他几台射电望远镜观测到的射电数据，证实了射电频谱在短时间内的极端变化。这种光谱行为被认为反映了与无线电和 X 射线中这些极端活动相关的喷射斑点的不透明度变化。我们的 1.4 GHz 无线电数据预计将有助于研究黑洞周围吸积和抛射现象的物理学。分别。我们还通过收集其他几台射电望远镜观测到的射电数据，证实了射电频谱在短时间内的极端变化。这种光谱行为被认为反映了与无线电和 X 射线中这些极端活动相关的喷射斑点的不透明度变化。我们的 1.4 GHz 无线电数据预计将有助于研究黑洞周围吸积和抛射现象的物理学。分别。我们还通过收集其他几台射电望远镜观测到的射电数据，证实了射电频谱在短时间内的极端变化。这种光谱行为被认为反映了与无线电和 X 射线中这些极端活动相关的喷射斑点的不透明度变化。我们的 1.4 GHz 无线电数据预计将有助于研究黑洞周围吸积和抛射现象的物理学。