Global e-VLBI observations of the gamma-ray narrow line Seyfert 1 PMN J0948+0022
Global e-VLBI observations of the gamma-ray narrow line Seyfert 1 PMN J0948+0022
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DOI：
10.1051/0004-6361/201116639
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发表时间：
2011-02
影响因子：
6.5
通讯作者：
M. Giroletti;Z. Paragi;H. Bignall;A. Doi;L. Foschini;K. Gabányi;C. Reynolds;J. Blanchard;R. M. C
中科院分区：
文献类型：
--
作者：
M. Giroletti;Z. Paragi;H. Bignall;A. Doi;L. Foschini;K. Gabányi;C. Reynolds;J. Blanchard;R. M. C
上下文越来越多的证据表明，射电强窄线塞弗特1（RL-NLS 1）星系中存在相对论性喷流。目标。我们限制了第一个在伽玛射线中探测到的RL-NLS 1星系PMN J 0948 +0022的射电发射的观测特性，即，它的通量密度和总强度和偏振结构，它的紧凑性和可变性。方法.我们进行了三个实时e-VLBI观测的PMNJ 0948 +0022在22 GHz，使用全球阵列，包括望远镜在欧洲，东亚和澳大利亚。这是有史以来第一次使用全球阵列进行e-VLBI科学观测，最大基线长度达到12458公里。这些观测是2009年大型多波长活动的一部分。结果在所有三个时期都检测到源。该结构由一个比55 ° ias更紧凑的明亮分量和一个位置角为35 °的较暗分量主导。相对论光束所需的观察到的亮度温度为3.4 i？1011K在约1%的水平下检测到偏振。结论. VLBI观测得到的参数和宽波段性质证实了PMNJ 0948 +0022与平谱射电类星体相似。全球e-VLBI是一种可靠的、有前途的研究手段。
Context. There is growing evidence of relativistic jets in radio-loud narrow-line Seyfert 1 (RL-NLS1) galaxies. Aims. We constrain the observational properties of the radio emission in the first RL-NLS1 galaxy ever detected in gamma-rays, PMN J0948+0022, i.e., its flux density and structure in both total intensity and polarization, its compactness, and variability. Methods. We performed three real-time e-VLBI observations of PMN J0948+0022 at 22 GHz, using a global array including telescopes in Europe, East Asia, and Australia. These are the first e-VLBI science observations ever carried out with a global array, reaching a maximum baseline length of 12 458 km. The observations were part of a large multiwavelength campaign in 2009. Results. The source is detected at all three epochs. The structure is dominated by a bright component, more compact than 55 ¥ias, with a fainter component at a position angle ¥e i 35◦. Relativistic beaming is required by the observed brightness temperature of 3.4 i? 1011 K. Polarization is detected at a level of about 1%. Conclusions. The parameters derived by the VLBI observations, in addition to the broad-band properties, confirm that PMN J0948+0022 is similar to flat spectrum radio quasars. Global e-VLBI is a reliable and promising technique for future studies.