English

The Distances of SNR W41 and overlapping HII regions

Astrophysics 2009-11-13 v2

Abstract

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^{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±\pm2 km/s and the CO cloud at radial velocity 95±\pm5 km/s is behind W41. Because an extended TeV source, a diffuse X-ray enhancement and a large molecular cloud at radial velocity 77±\pm5 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 (\sim9.9 kpc and \sim 10.6 kpc respectively) of their recombination-line velocities (103±\pm0.5 km/s and 89.6±\pm2.1 km/s respectively), G23.07-0.37 is at the near kinematic distance (4.4±\pm0.3 kpc) of its recombination-line velocity (82.7±\pm2.0 km/s), and G23.27-0.27 is probably at the near kinematic distance (4.1±\pm0.3 kpc) of its recombination-line velocity (76.1±\pm0.6 km/s).

Keywords

Cite

@article{arxiv.0708.3377,
  title  = {The Distances of SNR W41 and overlapping HII regions},
  author = {Denis A. Leahy and Wenwu Tian},
  journal= {arXiv preprint arXiv:0708.3377},
  year   = {2009}
}

Comments

11 pages, 3 figs., 2 tables, accepted by AJ