An Accurate Distance to High-Velocity Cloud Complex C
Astrophysics
2009-11-13 v2
Abstract
We report an accurate distance of d = 10+/-2.5kpc to the high-velocity cloud Complex C. Using high signal-to-noise Keck/HIRES spectra of two horizontal-branch stars, we have detected CaII K absorption lines from the cloud. Significant non-detections toward a further 3 stars yield robust lower distance limits. The resulting HI mass of Complex C is 4.9^{+2.8}_{-2.2} x 10^6 Msun; a total mass of 8.2^{+4.6}_{-2.6} x 10^6 Msun is implied, after corrections for helium and ionization. At 10kpc, Complex C has physical dimensions 3x15 kpc, and if it is as thick as it is wide, then the average density is log<n> ~ -2.5. We estimate the contribution of Complex C to the mass influx may be as high as ~0.14 Msun/yr.
Keywords
Cite
@article{arxiv.0712.0612,
title = {An Accurate Distance to High-Velocity Cloud Complex C},
author = {C. Thom and J. E. G. Peek and M. E. Putman and Carl Heiles and K. M. G. Peek and R. Wilhelm},
journal= {arXiv preprint arXiv:0712.0612},
year = {2009}
}
Comments
Resubmitted to ApJ. 8 figures