This page lists the Seminars that were given virtually on zoom in 2024. The EAO staff would like to thank all guest speakers and encourage new astronomers/instrument specialists to give virtual talks..
April 9th, 14:00 (HST)
Speaker: Yutaro Kofuji (Univerisy of Tokyo)
Title: Ultra-wide-band VERA observation of Sgr A*
Abstract:
We present the results of the monitor observation of Sgr A* at 43 GHz using the Japanese VLBI, VERA. With the recent update, VERA has an expanded bandwidth of 2048 MHz. Our high-sensitivity observations enabled us to detect the signature of non-zero closure phases in the triangle with the longest baseline, which could be attributed to the refractive scattering effect. We also confirmed the observed and intrinsic size of Sgr A* did not significantly change from 2018 to 2020. Based on our findings, we discuss potential ways to constrain the scattering properties using this data.
Abstract:
We present the results of the monitor observation of Sgr A* at 43 GHz using the Japanese VLBI, VERA. With the recent update, VERA has an expanded bandwidth of 2048 MHz. Our high-sensitivity observations enabled us to detect the signature of non-zero closure phases in the triangle with the longest baseline, which could be attributed to the refractive scattering effect. We also confirmed the observed and intrinsic size of Sgr A* did not significantly change from 2018 to 2020. Based on our findings, we discuss potential ways to constrain the scattering properties using this data.
April 9th, 14:00 (HST)
Speaker: Wu Jiang (SHAO)
Title:Simultaneous multifrequency observing system for (sub)mm-VLBI.
Abstract:
The simultaneous multifrequency receiving technique has been demonstrated to have great advantages for mm-VLBI observations. I will report some successful experiments with this technique, such as the detections of 3mm VLBI cores of LLAGNs M81*, M84*, M104*, and NGC4261, as well as positioning the black hole M87*. I will also present it works as a promising technique for supermassive black hole binaries and more supermassive black hole shadows.