Turbulent magnetic field in the H II region Sh 2-27
文献类型：期刊论文
| 作者 | Raycheva, N. C.1; Haverkorn, M.1; Ideguchi, S.1; Stil, J. M.2; Gaensler, B. M.3; Sun, X.4; Han, J. L.5,6; Carretti, E.7; Gao, X. Y.5; Wijte, T.1 |
| 刊名 | ASTRONOMY & ASTROPHYSICS
 |
| 出版日期 | 2022-08-02 |
| 卷号 | 663页码:13 |
| ISSN号 | 0004-6361 |
| 关键词 | HII regions - ISM magnetic fields - techniques polarimetric - turbulence |
| DOI | 10.1051/0004-6361/202039474 |
| 英文摘要 | Context. Magnetic fields in the turbulent interstellar medium (ISM) are a key element in understanding Galactic dynamics, but there are many observational challenges. One useful probe for studying the magnetic field component parallel to the line of sight (LoS) is Faraday rotation of linearly polarized radio synchrotron emission, combined with H alpha observations. H ii regions are the perfect laboratories to probe such magnetic fields as they are localized in space, and are well-defined sources often with known distances and measurable electron densities. We chose the H ii region Sharpless 2-27 (Sh 2-27) as it is located at intermediate latitudes (b similar to 23 degrees), meaning that it suffers from little LoS confusion from other sources. In addition, it has a large angular diameter (similar to 10 degrees), enabling us to study the properties of its magnetic field over a wide range of angular scales. Aims. By using a map of the magnetic field strength along the LoS (B-parallel to)for the first time, we investigate the basic statistical properties of the turbulent magnetic field inside Sh 2-27. We study the scaling of the magnetic field fluctuations, compare it to the Kolmogorov scaling, and attempt to find an outer scale of the turbulent magnetic field fluctuations. Methods. We used the polarized radio synchrotron emission data from the S-band Polarization All-Sky Survey (S-PASS) at 2.3 GHz, which allowed us to test the impact of Sh 2-27 on diffuse Galactic synchrotron polarization. We estimated the rotation measure (RM) caused by the H ii region, using the synchrotron polarization angle. We used the H alpha data from the Southern H alpha Sky Survey Atlas to estimate the free electron density (n(e)) in the H ii region. Using an ellipsoid model for the shape of Sh 2-27, and with the observed RM and emission measure (EM), we estimated the LoS averaged B(parallel to)for each LoS within the ellipsoid. To characterize the turbulent magnetic field fluctuations, we computed a second-order structure function of B-parallel to We compared the structure function to Kolmogorov turbulence, and to simulations of Gaussian random fields processed in the same way as the observations. Results. We present the first continuous map of B-parallel to computed using the diffuse polarized radio emission in Sh 2-27. We estimate the median value of n(e) as 7.3 +/- 0.1 cm(-3), and the median value of B-parallel to as -4.5 +/- 0.1 mu G, which is comparable to the magnetic field strength in diffuse ISM. The slope of the structure function of the estimated B-||-map is found to be slightly steeper than Kolmogorov, consistent with our Gaussian-random-field B(parallel to)simulations revealing that an input Kolmogorov slope in the magnetic field results in a somewhat steeper slope in B-parallel to.These results suggest that the lower limit to the outer scale of turbulence is 10 pc in the H ii region, which is comparable to the size of the computation domain. Conclusions. The structure functions of B-parallel to fluctuations in Sh 2-27 show that the magnetic field fluctuations in this H ii region are consistent with a Kolmogorov-like turbulence. Comparing the observed and simulated B-parallel to structure functions results in the estimation of a lower limit to the outer scale of the turbulent magnetic field fluctuations of 10 pc, which is limited by the size of the field of view under study. This may indicate that the turbulence probed here could actually be cascading from the larger scales in the ambient medium, associated with the interstellar turbulence in the general ISM, which is illuminated by the presence of Sh 2-27. |
| WOS关键词 | CM POLARIZATION SURVEY ; GALACTIC PLANE ; INTERSTELLAR TURBULENCE ; FARADAY-ROTATION ; IONIZED-GAS ; MOLECULAR CLOUDS ; DEPOLARIZATION CANALS ; DENSITY-FLUCTUATIONS ; LINEAR-POLARIZATION ; RADIO-CONTINUUM |
| 资助项目 | Dutch Research Council (NWO)[629.001.022] ; European Research Council (ERC) under the European Union[772663] ; Natural Sciences and Engineering Research Council of Canada (NSERC)[2019-04848] ; Natural Sciences and Engineering Research Council of Canada (NSERC)[RGPIN-2015-05948] ; University of Toronto ; Canada Research Chairs program ; National Natural Science Foundation of China[11763008] ; National Natural Science Foundation of China[11988101] ; CAS-NWO cooperation programme[GJHZ1865] ; National Science Foundation ; David Dunlap family |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| 出版者 | EDP SCIENCES S A |
| WOS记录号 | WOS:000835006700002 |
| 资助机构 | Dutch Research Council (NWO) ; Dutch Research Council (NWO) ; European Research Council (ERC) under the European Union ; European Research Council (ERC) under the European Union ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; University of Toronto ; University of Toronto ; Canada Research Chairs program ; Canada Research Chairs program ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS-NWO cooperation programme ; CAS-NWO cooperation programme ; National Science Foundation ; National Science Foundation ; David Dunlap family ; David Dunlap family ; Dutch Research Council (NWO) ; Dutch Research Council (NWO) ; European Research Council (ERC) under the European Union ; European Research Council (ERC) under the European Union ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; University of Toronto ; University of Toronto ; Canada Research Chairs program ; Canada Research Chairs program ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS-NWO cooperation programme ; CAS-NWO cooperation programme ; National Science Foundation ; National Science Foundation ; David Dunlap family ; David Dunlap family ; Dutch Research Council (NWO) ; Dutch Research Council (NWO) ; European Research Council (ERC) under the European Union ; European Research Council (ERC) under the European Union ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; University of Toronto ; University of Toronto ; Canada Research Chairs program ; Canada Research Chairs program ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS-NWO cooperation programme ; CAS-NWO cooperation programme ; National Science Foundation ; National Science Foundation ; David Dunlap family ; David Dunlap family ; Dutch Research Council (NWO) ; Dutch Research Council (NWO) ; European Research Council (ERC) under the European Union ; European Research Council (ERC) under the European Union ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; University of Toronto ; University of Toronto ; Canada Research Chairs program ; Canada Research Chairs program ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS-NWO cooperation programme ; CAS-NWO cooperation programme ; National Science Foundation ; National Science Foundation ; David Dunlap family ; David Dunlap family |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/87739]  |
| 专题 | 中国科学院国家天文台 |
| 通讯作者 | Raycheva, N. C. |
| 作者单位 | 1.Radboud Univ Nijmegen, Dept Astrophys IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands 2.Univ Calgary, Dept Phys & Astron, 2500 Univ Dr NW, Calgary, AB T2N 1N4, Canada 3.Dunlap Inst Astron & Astrophys, 50 St George St, Toronto, ON M5S 3H4, Canada 4.Yunnan Univ, Sch Phys & Astron, Kunming 650500, Yunnan, Peoples R China 5.Chinese Acad Sci, CAS Key Lab FAST, NAOC, Beijing 100101, Peoples R China 6.Univ Chinese Acad Sci, Sch Astron, Beijing 100049, Peoples R China 7.INAF, Ist Radioastron, Via Gobetti 101, I-40129 Bologna, Italy |
| 推荐引用方式 GB/T 7714 | Raycheva, N. C.,Haverkorn, M.,Ideguchi, S.,et al. Turbulent magnetic field in the H II region Sh 2-27[J]. ASTRONOMY & ASTROPHYSICS,2022,663:13. |
| APA | Raycheva, N. C..,Haverkorn, M..,Ideguchi, S..,Stil, J. M..,Gaensler, B. M..,...&Wijte, T..(2022).Turbulent magnetic field in the H II region Sh 2-27.ASTRONOMY & ASTROPHYSICS,663,13. |
| MLA | Raycheva, N. C.,et al."Turbulent magnetic field in the H II region Sh 2-27".ASTRONOMY & ASTROPHYSICS 663(2022):13. |
入库方式： OAI收割
来源：国家天文台
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