The Galactic Nature of High Velocity Cloud Complex WB
Abstract
We have detected absorption lines from the High Velocity Cloud Complex WB in the spectrum of the star HE1048+0231. This detection sets an upper distance limit to the cloud of 8.8^{+2.3}_{-1.3} kpc. Non-detection (at >4 sigma confidence) in the star HE1138-1303 at 7.7 +/- 0.2 kpc sets a probable lower limit. The equivalent width of the CaII K line due to the HVC (114.6 +/- 4.4 mA) corresponds to a column density of 1.32 +/- 0.05 x 10^12 cm^-2. Using an HI spectrum from the Leiden/Argentine/Bonn survey, we calculated N(CaII)/N(HI) = 81 +/- 16 x 10^-9. These distance limits imply an HI mass limit of 3.8 x 10^5 Msun < M_HI < 4.9 x 10^5 Msun. The upper distance limit imposed by these observations shows that this HVC complex has a probable Galactic or circum-Galactic origin. Future metallicity measurements will be able to confirm or refute this interpretation.
Keywords
Cite
@article{arxiv.astro-ph/0601139,
title = {The Galactic Nature of High Velocity Cloud Complex WB},
author = {C. Thom and M. E. Putman and B. K. Gibson and N. Christlieb and C. Flynn and T. C. Beers and R. Wilhelm and Y. S. Lee},
journal= {arXiv preprint arXiv:astro-ph/0601139},
year = {2009}
}
Comments
2 Figures, 1 Table. ApJL accepted