期刊
ASTRONOMY & ASTROPHYSICS
卷 441, 期 2, 页码 491-511出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361:20042342
关键词
galaxies : individual : M83; galaxies : spiral; galaxies : ISM; ISM : dust, extinction; ISM : magnetic fields
We present a detailed mid-infrared study of the nearby, face-on spiral galaxy M83 based on ISOCAM data. M83 is a unique case study, since a wide variety of MIR broad-band filters as well as spectra, covering the wavelength range of 4 to 18 mu m, were observed and are presented here. Emission maxima trace the nuclear and bulge area, star-formation regions at the end of the bar, as well as the inner spiral arms. The fainter outer spiral arms and interarm regions are also evident in the MIR map. Spectral imaging of the central 3' x 3' ( 4 kpc x 4 kpc) field allows us to investigate five regions of different environments. The various MIR components ( very small grains, polycyclic aromatic hydrocarbon ( PAH) molecules, ionic lines) are analyzed for different regions throughout the galaxy. In the total lambda 4 mu m to 18 mu m wavelength range, the PAHs dominate the luminosity, contributing between 60% in the nuclear and bulge regions and 90% in the less active, interarm regions. Throughout the galaxy, the underlying continuum emission from the small grains is always a smaller contribution in the total MIR wavelength regime, peaking in the nuclear and bulge components. The implications of using broad-band filters only to characterize the mid-infrared emission of galaxies, a commonly used ISOCAM observation mode, are discussed. We present the first quantitative analysis of new H alpha and lambda 6 cm VLA+Effelsberg radio continuum maps of M83. The distribution of the MIR emission is compared with that of the CO, HI, R band, H alpha and lambda 6 cm radio. A striking correlation is found between the intensities in the two mid-infrared filter bands and the lambda 6 cm radio continuum. To explain the tight mid-infrared-radio correlation we propose the anchoring of magnetic field lines in the photoionized shells of gas clouds.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据