Flux density variations of radio sources in M82 over the last three decades
Flux density variations of radio sources in M82 over the last three decades
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DOI：
10.1093/mnras/stt231
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发表时间：
2012-09
影响因子：
4.8
通讯作者：
M. Gendre;D. Fenech;R. Beswick;T. Muxlow;M. Argo
中科院分区：
文献类型：
--
作者：
M. Gendre;D. Fenech;R. Beswick;T. Muxlow;M. Argo
本文介绍了2009-2010年利用多元素无线电干涉仪网络(MERLIN)在5 GHz和e-MERLIN网络在6 GHz获得的星暴星系M82的监测结果。将几个5 GHz的梅林历元组合成一个噪声水平为33.0uJy/Bm的MAP，识别出52个离散源，其中大部分是超新星遗迹和HII区。其中包括三个在2002年5 GHz梅林监测期间没有探测到的天体：超新星SN2008iz，瞬变源43.78+59.3，以及一个新的超新星残余壳。研究了长期(1981-2010年)、中期(2002-2010年)和短期(2009-2010年)的通量密度变化。我们发现，在大部分样品中，M82的SNR的通量密度保持不变(~95%)。此外，除了SN2008iz和著名的变源41.95+57.5外，还有两个源在2009-2010年期间显示出短期和中期变化。这些源是M82中最紧密的信噪比之一，这些通量密度的变化可能是由于激波所在的星周和星际介质的变化所致。
This paper presents the results of the 2009-2010 monitoring sessions of the starburst galaxy M82, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN) at 5GHz and e-MERLIN at 6GHz. Combining several 5GHz MERLIN epochs to form a map with 33.0 uJy/bm noise level, 52 discrete sources, mostly supernova remnants and HII regions, are identified. These include three objects which were not detected in the 2002 5GHz MERLIN monitoring session: supernova SN2008iz, the transient source 43.78+59.3, and a new supernova remnant shell. Flux density variations, in the long (1981 to 2010), medium (2002 to 2010) and short (2009 to 2010) term, are investigated. We find that flux densities of SNRs in M82 stay constant in most of the sample (~95%). In addition, aside from SN2008iz and the well-known variable source 41.95+57.5, two sources display short and medium term variations over the period 2009-2010. These sources being among the most compact SNR in M82, these flux density variations could be due to changes in the circumstellar and interstellar medium in which the shocks travel.