LOFAR探测到仙后座A方向的低频射电复合线
星系天体物理
2013-02-14 v1
摘要
使用低频阵列（LOFAR）的低频段天线以高光谱分辨率观测了仙后座A。这使得能够沿该源的视线方向搜寻射电复合线（RRLs）。从两个独立的LOFAR数据集，在40至50 MHz之间以大于5的信噪比探测到了五条处于吸收状态的碳α射电复合线。在我们的光谱中，对整个超新星遗迹提取的射电复合线的导出线速度（v_LSR ~ -50 km/s）和积分光深（~ 13 s^-1）在每个LOFAR数据集内以及与此前报道的结果都是一致的。我们首次能够在低于330 MHz的频率下对遗迹最亮热斑提取光谱。这些光谱显示出显著更高（15-80%）的积分光深，表明在遗迹表面的吸收气体分布中存在约1 pc量级的小尺度角结构。我们还对氢和氦射电复合线的峰值光深设定了3×10^-4的上限。这些结果证明，LOFAR具有所需的光谱稳定性和灵敏度来研究十米波段的微弱复合线。
引用
@article{arxiv.1302.3128,
title = {LOFAR detections of low-frequency radio recombination lines towards Cassiopeia A},
author = {Ashish Asgekar and J. B. R. Oonk and S. Yatawatta and R. J. van Weeren and J. P. McKean and G. White and N. Jackson and J. Anderson and I. M. Avruch and F. Batejat and R. Beck and M. E. Bell and M. R. Bell and I. van Bemmel and M. J. Bentum and G. Bernardi and P. Best and L. Birzan and A. Bonafede and R. Braun and F. Breitling and R. H. van de Brink and J. Broderick and W. N. Brouw and M. Bruggen and H. R. Butcher and W. van Cappellen and B. Ciardi and J. E. Conway and F. de Gasperin and E. de Geus and A. de Jong and M. de Vos and S. Duscha and J. Eisloffel and H. Falcke and R. A. Fallows and C. Ferrari and W. Frieswijk and M. A. Garrett and J-M. Griesmeier and T. Grit and A. W. Gunst and T. E. Hassall and G. Heald and J. W. T. Hessels and M. Hoeft and M. Iacobelli and H. Intema and E. Juette and A. Karastergiou and J. Kohler and V. I. Kondratiev and M. Kuniyoshi and G. Kuper and C. Law and J. van Leeuwen and P. Maat and G. Macario and G. Mann and S. Markoff and D. McKay-Bukowski and M. Mevius and J. C. A. Miller-Jones and J. D. Mol and R. Morganti and D. D. Mulcahy and H. Munk and M. J. Norden and E. Orru and H. Paas and M. Pandey-Pommier and V. N. Pandey and R. Pizzo and A. G. Polatidis and W. Reich and H. Rottgering and B. Scheers and A. Schoenmakers and J. Sluman and O. Smirnov and C. Sobey and M. Steinmetz and M. Tagger and Y. Tang and C. Tasse and R. Vermeulen and C. Vocks and R. A. M. J. Wijers and M. W. Wise and O. Wucknitz and P. Zarka},
journal= {arXiv preprint arXiv:1302.3128},
year = {2013}
}
备注
Accepted for publication in A&A Letters; 5 pages, 4 colour figures