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arXiv · 0712.0612

An Accurate Distance to High-Velocity Cloud Complex C

C. Thom·J. E. G. Peek·M. E. Putman·Carl Heiles·K. M. G. Peek·R. Wilhelm
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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 ~ -2.5. We estimate the contribution of Complex C to the mass influx may be as high as ~0.14 Msun/yr.

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C. Thom, J. E. G. Peek, M. E. Putman, Carl Heiles, K. M. G. Peek, R. Wilhelm. 2008-04-23. An Accurate Distance to High-Velocity Cloud Complex C. https://doi.org/10.1086/589960

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