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HI Absorption Against the 40 km s−1 Cloud and the Circum-nuclear Disk in Sgr A

Published online by Cambridge University Press:  23 September 2016

Joan Lasenby ,
F. Yusef-Zadeh  and
Anthony N. Lasenby
Joan Lasenby
Affiliation:
Mullard Radio Astronomy Observatory, Cambridge, UK
F. Yusef-Zadeh
Affiliation:
NASA/Goddard Space Flight Center and Northwestern University

Abstract

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HI absorption studies of the Sgr A complex based upon recent VLA2 observations, show that the 40 km s−1 molecular cloud lies behind the Sgr A West region, and that the cloud may be physically associated with the Sgr A East non-thermal shell. The absorbing gas over the range +30 to +60km s−1 lies mainly between the eastern edge of the Sgr A East shell and the western boundary of a cluster of HII regions. There is a pronounced velocity gradient over this region, and at 40 km s−1 similar morphology is apparent between the distribution of atomic hydrogen and the edge of the Sgr A East shell. The physical association of the 40 km s−1 cloud and the Sgr A East shell, and the placing of the 40 km s−1 cloud behind Sgr A West, are consistent with recent evidence which has demonstrated that Sgr A West lies infront of Sgr A East. The HI optical depth maps of the circum-nuclear disk plus a new HI feature associated with the northern extension of Sgr A West will be presented.

Type
The Environment of the SGR A Complex
Information
Symposium - International Astronomical Union , Volume 136: The Galactic Center , 1989 , pp. 365 - 370
Copyright
Copyright © Kluwer 1989 

References

Bally, J., Stark, A.A., Wilson, R.W. and Henkel, C. 1987, Ap. J.Suppl. , 65, 13.CrossRefGoogle Scholar
Brown, R.L. and Liszt, H.S. 1984 Ann. Rev. Astr. Ap. , 24, 223.CrossRefGoogle Scholar
Ekers, R., van Gorkom, J., Schwarz, J.H., and Goss, W.M. 1983, Astron. Astrophys. , 122, 143.Google Scholar
Geballe, T. 1988 Presented at the IAU Symposium no. 136 on the Galactic Center , ed. Morris, M. CrossRefGoogle Scholar
Goss, W.M., Schwarz, U.J., van Gorkom, J.H. and Ekers, R.D. 1985, M.N.R.A.S. , 215, 69p.CrossRefGoogle Scholar
Güsten, R. and Downes, D. 1980, Astron. Astrophys. , 87, 6.Google Scholar
Güsten, R., Walmsley, C.M. and Pauls, T. 1981, Astron. Astrophys. , 103, 197.Google Scholar
Lasenby, J., Lasenby, A.N. and Yusef-Zadeh, F. 1988 submitted to Ap.J.; Presented at the IAU Symposium no.136 on the Galactic Center , ed. Morris, M. CrossRefGoogle Scholar
Liszt, H.S., van der Hulst, J.M., Burton, W.B. and Ondrechen, M.B. 1983, Astron. Astrophys. , 126, 341.Google Scholar
Liszt, H.S., Burton, W.B. and van der Hulst, J.M. 1985, Astron. Astrophys. , 142, 247.Google Scholar
Mezger, P.G., Zylka, R., Salter, C.J., Wink, J.E., Chini, R. and Kreysa, E. 1988 Presented at the IAU Symposium no. 136 on the Galactic Center , ed. Morris, M. CrossRefGoogle Scholar
Okumura-kawabe, S., Ishiguru, M., Fomalont, E.B., Chikada, Y., Kasuga, T., et al. 1988, Presented at the IAU Symposium no. 136 on the Galactic Center , ed. Morris, M. CrossRefGoogle Scholar
Pedlar, A., Anantharamaiah, K.R., Ekers, R.D., Goss, W.M., van Gorkom, J.H., Schwarz, U.J., and Zhao, J. 1988 Presented at the IAU Symposium no. 136 on the Galactic Center , ed. Morris, M. Google Scholar
Sandqvist, Aa, 1974, Astron. Astrophys. , 33, 413.Google Scholar
Schwarz, U.J., Shaver, P. and Ekers, R.D. 1977, Astron. Astrophys. , 54, 863.Google Scholar
Serabyn, E. Güsten, R., Wink, J.E., Walmsley, C.M. and Zylka, R., 1986, Astron. Astrophys. , 169, 85.Google Scholar
Whiteoak, J.B., Rogstad, D.H., and Lockhart, I.A. 1974, Astron. A strophys. , 36, 245.Google Scholar
Yusef-Zadeh, F. and Morris, M. 1987 Ap.J. , 320, 545 [YM87].CrossRefGoogle Scholar