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تسجيل مستخدم جديدThe Distances of SNR W41 and overlapping HII regions
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New HI images from the VLA Galactic Plane Survey show prominent absorption features associated with the supernovae remnant G23.3-0.3 (SNR W41). We highlight the HI absorption spectra and the $^{13}$CO emission spectra of eight small regions on the face of W41, including four HII regions, three non-thermal emission regions and one unclassified region. The maximum velocity of absorption for W41 is 78$pm$2 km/s and the CO cloud at radial velocity 95$pm$5 km/s is behind W41. Because an extended TeV source, a diffuse X-ray enhancement and a large molecular cloud at radial velocity 77$pm$5 km/s are also projected at the center of W41, these yield the kinematic distance of 3.9 to 4.5 kpc for W41. For HII regions, our analyses reveal that both G23.42-0.21 and G23.07+0.25 are at the far kinematic distances ($sim$9.9 kpc and $sim$ 10.6 kpc respectively) of their recombination-line velocities (103$pm$0.5 km/s and 89.6$pm$2.1 km/s respectively), G23.07-0.37 is at the near kinematic distance (4.4$pm$0.3 kpc) of its recombination-line velocity (82.7$pm$2.0 km/s), and G23.27-0.27 is probably at the near kinematic distance (4.1$pm$0.3 kpc) of its recombination-line velocity (76.1$pm$0.6 km/s).
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