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  • Zhou, Chenlin; Zhu, Ming; Yuan, Jinghua; Wu, Yuefang; Yuan, Lixia; Moore, T J T; Eden, D J

    arXiv.org, 03/2019
    Paper, Journal Article

    We utilize multiple-waveband continuum and molecular-line data of CO isotopes, to study the dynamical structure and physical properties of the IRDC G31.97+0.07. We derive the dust temperature and H\(_2\) column density maps of the whole structure by SED fitting. The total mass is about \(2.5\times10^5\,M_{\odot}\) for the whole filamentary structure and about \(7.8\times10^4\,M_{\odot}\) for the IRDC. Column density PDFs produced from the column density map are generally in the power-law form suggesting that this part is mainly gravity-dominant. The flatter slope of the PDF of the IRDC implies that it might be compressed by an adjacent, larger \HII region. There are 27 clumps identified from the 850\,\micron \ continuum located in this filamentary structure. Based on the average spacing of the fragments in the IRDC, we estimate the age of the IRDC. The age is about \(6.4\,\)Myr assuming inclination angle \(i = 30^\circ\). For 18 clumps with relatively strong CO and \(^{13}\)CO (3-2) emission, we study their line profiles and stabilities. We find 5 clumps with blue profiles which indicate gas infall motion and 2 clumps with red profiles which indicate outflows or expansion. Only one clump has \(\alpha_\mathrm{vir} > 2\), suggesting that most clumps are gravitationally bound and tend to collapse. In the Mass-\(R_\mathrm{eq}\) diagram, 23 of 27 clumps are above the threshold for high-mass star formation, suggesting that this region can be a good place for studying high-mass star-forming.