Articles written in Journal of Astrophysics and Astronomy
Volume 32 Issue 1-2 March 2011 pp 25-28 Part 1. Blazar Observations in Radio
We report on VLA observations of HST-1 in M87 at 8 GHz from 2003–2007, during which a long major outburst occurs from radio to X-ray wave bands. At the VLA resolution, the flux density of HST-1 rises rapidly from 2003, peaks at the end of 2004, and then falls slowly in subsequent stages, which is similar to that in optical and X-ray wave bands. It appears that HST-1 moves with an apparent speed of 1.23𝑐 ± 0.91𝑐, and the fractional polarization keeps rising through the whole major outburst. The persistent increase in polarization level may mainly be attributed to the formation of a couple of new `subcomponents’ of relatively high degree of polarization within HST-1, and the weakening depolarization due to Faraday rotation and/or opacity through the whole major outburst.
Volume 32 Issue 1-2 March 2011 pp 61-63 Part 1. Blazar Observations in Radio
It was argued that 3C 66B, a nearby radio galaxy, harbors a supermassive black hole binary (SMBHB). To investigate this, a 4-epoch VLBA phase referencing imaging observation was performed in 2004–2005. Here we present some preliminary results of this project. We found a large position difference compared to previous results.
Volume 32 Issue 1-2 March 2011 pp 261-264 Part 7. Other Topics
VX Sgr, a semi-regular variable, is a red giant star with intense SiO maser emission at 43 GHz. The pumping mechanism of the circumstellar SiO masers has been controversial for decades since its discovery. In order to pursue this long-standing problem further, we have carried out simultaneous VLBA observations of two 7 mm SiO masers at five epochs in about two years. We present relatively aligned 𝑣 = 1 and 𝑣 = 2, 𝐽 = 1-0 SiO maser maps and discuss the dominant pumping mechanism, which may be epoch dependent or a combination of both mechanisms.
Volume 35 Issue 3 September 2014 pp 209-213 Part I: Blazar Observations in Radio
We report multi-frequency VLBA phase-referencing observation results of 3C 66A and 3C 66B, including high resolution maps and relative position measurements. The resulting images show similar morphology with that presented in previous works. We find core shift variations in both sources, indicating some physical condition changes in the jets.
Volume 35 Issue 3 September 2014 pp 379-380 Posters
We establish a simple model to describe the helical magnetic fields in AGN jets projected on the sky plane and the line-of-sight. This kind of profile has been detected in the polarimetric VLBI observation of many blazar objects, suggesting the existence of helical magnetic fields in these sources.
Volume 35 Issue 3 September 2014 pp 539-540 Part VII: Other Topics
We report the proper motions of SiO maser features around VX Sgr from the two-epoch VLBA observations (2006 December 15 and 2007 August 19). The majority of maser feature activities show a trend of outward motions. It is consistent with our previous finding that the outflow may play an important role for SiO maser pumping.
Volume 40 | Issue 5
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