Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz
Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz
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M82 核在 118 MHz 和 154 MHz 下的亚弧秒国际 LOFAR 射电图像
DOI：
10.1051/0004-6361/201425089
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发表时间：
2015
影响因子：
6.5
通讯作者：
Brüggen
中科院分区：
文献类型：
--
作者：
Varenius;Adebahr;Dettmar;Brüggen
附近星系M82中的核星暴为理解星星形成的物理学提供了一个极好的实验室。这个星系在过去被广泛观察，揭示了数十个嵌入在弥漫的自由吸收介质中的无线电明亮的紧凑物体。我们对M82中这种介质的结构和物理性质的理解可以通过低频下的高分辨率图像来大大提高，其中自由-自由吸收的影响是最突出的。在M82的中心星暴区，通过高强度的辐射来限制致密辐射和弥散辐射的低频光谱，使用国际LOFAR望远镜在110 - 126 MHz和146 - 162 MHz下观测M82。使用标准技术从甚长基线干涉测量法获得图像。结果154 MHz国际基线成像在低频（<327 MHz）下的综合图像分辨率（0.3 "）和灵敏度（σ= 0.15 mJy/beam）均为新的成像记录。我们在154 MHz探测到16个物体，其中6个也在118 MHz。在154兆赫探测到的7个物体以前没有编入目录。对于先前检测到的九个对象，我们通过拟合模型获得光谱指数和发射测量光谱（结合LOFAR与文献数据）。四个较弱，但解决功能也被发现：一个线性（50 pc）的灯丝和其他三个解决对象，其中两个显示了一个明确的壳结构。我们没有探测到任何来自超新星2008 iz或射电瞬变源43.78+59.3的辐射。使用远程基线获得的图像显示了与M82外流有关的漫射发射，在边缘形成恒星的盘区域亮度降低。
ContextThe nuclear starburst in the nearby galaxy M82 provides an excellent laboratory for understanding the physics of star formation. This galaxy has been extensively observed in the past, revealing tens of radio-bright compact objects embedded in a diffuse free-free absorbing medium. Our understanding of the structure and physics of this medium in M82 can be greatly improved by high-resolution images at low frequencies where the effects of free-free absorption are most prominent.AimsThe aims of this study are, firstly, to demonstrate imaging using international baselines of the Low Frequency Array (LOFAR), and secondly, to constrain low-frequency spectra of compact and diffuse emission in the central starburst region of M82 via high-resolution radio imaging at low frequencies.MethodsThe international LOFAR telescope was used to observe M82 at 110−126 MHz and 146−162 MHz. Images were obtained using standard techniques from very long baseline interferometry. images were obtained at each frequency range: one only using international baselines, and one only using the longest Dutch (remote) baselines.ResultsThe 154 MHz image obtained using international baselines is a new imaging record in terms of combined image resolution (0.3′′) and sensitivity (σ= 0.15 mJy/beam) at low frequencies (<327 MHz). We detected 16 objects at 154 MHz, six of these also at 118 MHz. Seven objects detected at 154 MHz have not been catalogued previously. For the nine objects previously detected, we obtained spectral indices and emission measures by fitting models to spectra (combining LOFAR with literature data). Four weaker but resolved features are also found: a linear (50 pc) filament and three other resolved objects, of which two show a clear shell structure. We do not detect any emission from either supernova 2008iz or from the radio transient source 43.78+59.3. The images obtained using remote baselines show diffuse emission, associated with the outflow in M82, with reduced brightness in the region of the edge-on star-forming disk.
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影响因子：
4.8
作者：
M. Gendre;D. Fenech;R. Beswick;T. Muxlow;M. Argo
通讯作者：
M. Gendre;D. Fenech;R. Beswick;T. Muxlow;M. Argo
18 MHz 木星甚长基线干涉测量
DOI：
--
发表时间：
1970
期刊：
影响因子：
--
作者：
T. Carr;M. Lynch;M. P. Paul;G. W. Brown;J. May;N. Six;V. M. Robinson;W. F. Block
通讯作者：
W. F. Block
M82 核中选定紧凑源的射电频谱
DOI：
10.1086/305894
发表时间：
1998
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Allen;P. Kronberg
通讯作者：
P. Kronberg
LOFAR 长基线快照校准器调查
影响因子：
4.8
作者：
J. Mold'on;A. Deller;O. Wucknitz;N. Jackson;A. Drabent;T. Carozzi;J. Conway;A. Kapińska;P. McKean;L. Morabito;E. Varenius;P. Zarka;J. Anderson;A. Asgekar;I. Avruch;M. Bell;M. Bentum;G. Bernardi;P. Best;L. Bîrzan;J. Bregman;F. Breitling;J. Broderick;M. Bruggen;H. Butcher;D. Carbone;B. Ciardi;F. Gasperin;E. D. Geus;S. Duscha;J. Eisloffel;D. Engels;H. Falcke;R. Fallows;R. Fender;C. Ferrari;W. Frieswijk;M. Garrett;J. Grießmeier;A. Gunst;J. Hamaker;T. Hassall;G. Heald;M. Hoeft;E. Juette;A. Karastergiou;V. Kondratiev;M. Kramer;M. Kuniyoshi;G. Kuper;P. Maat;G. Mann;S. Markoff;R. McFadden;D. McKay;R. Morganti;H. Munk;M. Norden;A. Offringa;E. Orrù;H. Paas;M. Pandey;R. Pizzo;A. Polatidis;W. Reich;H. Rottgering;A. Rowlinson;A. Scaife;D. Schwarz;J. Sluman;O. Smirnov;B. Stappers;M. Steinmetz;M. Tagger;Y. Tang;C. Tasse;S. Thoudam;M. C. Toribio;R. Vermeulen;C. Vocks;R. Weeren;S. White;M. Wise;S. Yatawatta;A. Zensus
通讯作者：
A. Zensus
星爆星系 M82 中的年轻超新星
DOI：
--
发表时间：
1984
期刊：
影响因子：
--
作者：
S. W. Unger;A. Pedlar;D. Axon;P. Wilkinson;P. Appleton
通讯作者：
P. Appleton