Abstract
OPTICAL images of the arms of spiral galaxies invariably show massive blue stars forming in ridges of interstellar gas and dust1. These are particularly striking in 'grand-design' galaxies, in which the stellar positions are influenced by spiral density waves1. By contrast, many galaxies have a 'flocculent' appearance, with no obvious evidence of spiral structure at visible wavelengths. Here we report infrared observations of the prototype flocculent galaxy NGC2841, which reveal a remarkable system of long, dark spiral arms. These arms arise from concentrations of dust; they are hidden at optical wavelengths by light scattered from the dust. The mechanism that has organized the gas and dust into these dark arms is at present unclear; the arms might be highly sheared dense clouds, or they might correspond to density waves in the interstellar medium driven by an elongated central bulge, which would not affect the stable stellar disk.
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References
Elmegreen, D. M. & Elmegreen, B. G. Astrophys. J. Suppl. Ser. 54, 127–150 (1984).
Sandage, A. Hubble Atlas of Galaxies (Carnegie Instn, Washington DC, 1961).
Elmegreen, D. M. & Elmegreen, B. G. Mon. Not. R. astr. Soc. 201, 1021–1034 (1982).
Elmegreen, D. M. & Elmegreen, B. G. Astrophys. J. 364, 412–414 (1990).
Bertin, G. in Dynamics of Galaxies and Molecular Cloud Distributions (eds Combes, F. & Casoli, F.) 93–104 (Kluwer Academic, Dordrecht, 1991).
Elmegreen, B. G. & Thomasson, M. Astr. Astrophys. 272, 37–58 (1993).
Mark, J. W. K. Astrophys. J. 205, 363–378 (1976).
Toomre, A. in The Structure and Evolution of Normal Galaxies (eds Fall, S. M. & Lynden-Bell, D.) 111–136 (Cambridge Univ. Press, 1981).
Seiden, P. E. & Gerola, H. Astrophys. J. 233, 56–66 (1979).
Elmegreen, B. G. & Efremov, Yu. Astrophys. J. (in the press).
Wainscoat, R. J. & Cowie, L. L. Astr. J. 103, 332–337 (1992).
Block, D. L. & Wainscoat, R. J. Nature 353, 48–50 (1991).
Block, D. L. et al. Astrophys. 288, 365–382 (1994).
Rix, H. W. & Rieke, M. J. Astrophys. J. 418, 123–134 (1993).
Rix, H.-W. & Zaritsky, D. in Infrared Astronomy with Arrays: The Next Generation (ed. McLean, I. S.) 151–152 (Kluwer Academic, Dordrecht, 1994).
Wray, J. D. The Color Atlas of Galaxies (Cambridge Univ. Press, 1988).
Bosma, A. Astr. J. 86, 1825–1846 (1981).
Begeman, K. G. thesis, Univ. Groningen (1987).
Young, J. S. & Scoville, N. Astrophys. J. 260, L41–L44 (1982).
Braine, J. & Combes, F. Astr. Astrophys. 264, 433–443 (1992).
Block, D. L., Witt, A. N. & Grosbøl, P. in The Opacity of Spiral Disks (eds Davies, J. I. & Burstein, D.) 227–242 (Kluwer Academic, Dordrecht, 1995).
Brinks, E. & Burton, W. B. Astr. Astrophys. 141, 195–214 (1984).
Deul, E. R. & van der Hulst, J. M. Astr. Astrophys. Suppl. Ser. 67, 509–539 (1987).
Hodge, P. W. Astr. J. 85, 376–386 (1980).
Wozniak, H., Friedli, D., Martinet, L., Martin, P. & Bratschi, P. Astr. Astrophys. Suppl. Ser. 111, 115–152 (1995).
Stark, A. A. Astrophys. J. 213, 368–373 (1977).
Lindblad, B. Stockholm Obs. Ann. 19(2), 1–12 (1956).
Bertola, F., Rubin, V. C. & Zeilinger, W. W. Astrophys. J. 345, L29–L32 (1989).
Gerhard, O. E., Vietri, M. & Kent, S. M. Astrophys. J. 345, L33–L36 (1989).
Witt, A. N., Lindell, R. S., Block, D. L. & Evans, Rh. Astrophys. J. 427, 227–231 (1994).
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Block, D., Elmegreen, B. & Wainscoat, R. Smooth dark spiral arms in the flocculent galaxy NGC2841. Nature 381, 674–676 (1996). https://doi.org/10.1038/381674a0
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DOI: https://doi.org/10.1038/381674a0
