Phase-reference VLBI observations of the compact steep-spectrum source 3C 138

	Phase-reference VLBI observations of the compact steep-spectrum source 3C 138
	Shen, Zhi-Qiang ; Shang, Lin-Lin ; Jiang, Dong-Rong ; Cai, Hong-Bing ; Chen, Xi
刊名	PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
	2006
卷号	58 期号:6 页码:1033-1037
关键词	astrometry galaxies : active galaxies : quasars : individual (3C 138) radio continuum : galaxies techniques : interferometric
英文摘要	We describe a phase-reference VLBI observation that was conducted at 15.4 GHz by fast-switching VLBA antennas between the compact steep-spectrum radio source 3C 138 and the quasar PKS 0528 + 134, which are about 4 degrees away on the sky. By comparing the phase-reference mapping with the conventional hybrid mapping, we demonstrate the feasibility of high-precision astrometric measurements for sources separated by 4 degrees. VLBI phase-reference mapping preserves the relative phase information, and thus provides an accurate relative position between 3C 138 and PKS 0528 + 134 of Delta alpha = -9(m)46.(s)531000 +/- 0.(s)000003 and Delta delta = 3 degrees 6'26."90311 +/- 0."00007 (J2000.0) in right ascension and declination, respectively. This gives an improved position of the nucleus (component A) of 3C 138 in J2000.0 to be RA = 05(h)21(m)09.(s)885748 and Dec = 16 degrees 38'22."05261 under the assumption that the position of calibrator PKS 0528 + 134 is correct. We further made a hybrid map by performing several iterations of CLEAN and self-calibration on the phase-referenced data with the phase-reference map as an input model for the first phase self-calibration. Compared with the hybrid map from the limited visibility data directly obtained from fringe fitting 3C 138 data, this map has a similar dynamic range, but a higher angular resolution. Therefore, the phase-reference technique is not only a means of phase connection, but also a means of increasing the phase coherence time, and thus allowing the self-calibration technique to be applied to much weaker sources.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
收录类别	SCI
语种	英语
WOS记录号	WOS:000243365200012
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/19413]
专题	上海天文台_VLBI研究室
作者单位	1.Chinese Acad Sci, Astron Observ, Shanghai 200030, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China 3.Astron Observ, JOINGC, Shanghai, Peoples R China
推荐引用方式 GB/T 7714	Shen, Zhi-Qiang,Shang, Lin-Lin,Jiang, Dong-Rong,et al. Phase-reference VLBI observations of the compact steep-spectrum source 3C 138[J]. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN,2006,58(6):1033-1037.
APA	Shen, Zhi-Qiang,Shang, Lin-Lin,Jiang, Dong-Rong,Cai, Hong-Bing,&Chen, Xi.(2006).Phase-reference VLBI observations of the compact steep-spectrum source 3C 138.PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN,58(6),1033-1037.
MLA	Shen, Zhi-Qiang,et al."Phase-reference VLBI observations of the compact steep-spectrum source 3C 138".PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 58.6(2006):1033-1037.