Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-30T16:47:57.504Z Has data issue: false hasContentIssue false
  • English
  • Français

Density and Velocity Distribution of the Interstellar Gas

Published online by Cambridge University Press:  03 August 2017

H. C. van de Hulst
H. C. van de Hulst*
Affiliation:
Leiden Observatory, Leiden, The Netherlands

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The interstellar gas shows wide variations in density and in velocity. Common words to describe the existence of these variations are cloudiness for the density and turbulence for the velocity field. These terms have initially been introduced as vague descriptions and were not based on mathematical analysis or dynamical theory. The word cloud as used by astronomers did not always mean a region of large density with relatively sharp boundaries; nor did the word turbulence necessarily imply a velocity field with well-defined statistical regularities and energy dissipation by means of viscosity.

Type
Part I: Empirical Studies of Velocity Fields in, and Related Structure of, the Interstellar Medium
Information
Symposium - International Astronomical Union , Volume 8: Cosmical Gas Dynamics , July 1958 , pp. 913 - 923
Copyright
Copyright © American Physical Society 1958 

References

1 van de Hulst, , Muller, , and Oort, , Bull. Astron. Inst. Neth. 12, 117 (No. 452) (1954).Google Scholar

2 Morgan, , Whitford, , and Code, , Astrophys. J. 118, 318 (1953).CrossRefGoogle Scholar

3 Gum, C. S., Mem. Roy. Astron. Soc. 67, 156 (1955).Google Scholar

4 Kerr, , Hindman, , and Carpenter, , Nature 180, 677 (1957).Google Scholar

5 Thackeray, A. D., Mém. soc. roy. sci. Liège 15, 437 (1955).Google Scholar

6 Westerhout, G., (a) Bull Astron. Inst. Neth. 13, 201 (No. 475) (1957); (b) “Radio astronomy.” I. A. U. Symposium No. 4 (Cambridge University Press, New York, 1957), p. 22.Google Scholar

7 Walraven, , Muller, , and Oosterhoff, , Bull. Astron. Inst. Neth. 14, 81 (No. 484) (1958).Google Scholar

∗ Note added in proof (June, 1958).—Since this was written a map of the spiral structure in the galactic system based on a combined discussion of northern and southern data has been prepared for publication by Oort, Kerr, and Westerhout, Monthly Notices Roy. Astron. Soc. (to be published).Google Scholar

8 Schmidt, M., Bull. Astron. Inst. Neth. 13, 247 (No. 475) (1957).Google Scholar

9 van de Hulst, , Raimond, , and van Woerden, , Bull. Astron. Inst. Neth. 14, 1 (No. 480) (1957).Google Scholar

10 Schmidt, M., Bull. Astron. Inst. Neth. 13, 15 (No. 468) (1956).Google Scholar

11 Schmidt, M., Bull. Astron. Inst. Neth. 14, 17 (No. 480) (1957).Google Scholar

12 Pickelner, S. B., Izvest. Krymsk. Obs. 10, 74 (1953).Google Scholar

13 Spitzer, L., Astrophys. J. 124, 20 (1956).CrossRefGoogle Scholar

14 Pickelner, S. B. and Shklovsky, I. S., Astron. Zhur. 34, 145 (1957).Google Scholar

15 Baldwin, J. E., Monthly Notices Roy. Astron. Soc. 115, 691 (1956); “Radio astronomy,” I. A. U. Symposium No. 4 (Cambridge University Press, New York, 1957), p. 233.Google Scholar

† Note added in proof (June, 1958).—Measurements with a band width of 10 kcps show at the north pole (second field in Fig. 4) a much narrower line with top 22°K, total half-width g km/sec, and wings extending to ±50 km/sec. Any wings at velocities >70 km/sec, if present at all, must be well below 1°K.70+km/sec,+if+present+at+all,+must+be+well+below+1°K.>Google Scholar

16 van Woerden, , Rougoor, , and Oort, , Compt. rend. 244, 1691 (1957).Google Scholar

17 Strömgren, B., “Problems of cosmical aerodynamics,” Central Air Documents Office, Dayton, Ohio, 1951, p. 8.Google Scholar

18 Minkowski, R., “Gas dynamics of cosmic clouds,” I. A. U. Symposium No. 2 (North-Holland Publishing Company, Amsterdam, the Netherlands, 1955), p. 3.Google Scholar

19 Oort, J. H., “Gas dynamics of cosmic clouds,” I. A. U. Symposium No. 2 (North-Holland Publishing Company, Amsterdam, the Netherlands, 1955), p. 20.Google Scholar

20 Adams, W. S., Astrophys. J. 109, 354 (1949).CrossRefGoogle Scholar

21 Munch, G., (a) Publs. Astron. Soc. Pacific 65, 179 (1953); (b) Astrophys. J. 125, 42 (1957).CrossRefGoogle Scholar

22 Blaauw, A., Bull. Astron. Inst. Neth. 11, 459 (No. 436) (1952).Google Scholar

23 Spitzer, L. and Skumanich, A., Astrophys. J. 116, 452 (1952).Google Scholar

24 Hagen, , Lilley, , and McClain, , Astrophys. J. 122, 361 (1955).Google Scholar

25 Muller, C. A., Astrophys. J. 125, 830 (1957).CrossRefGoogle Scholar

26 Kahn, F. D., Mém. soc. roy. sci. Liège 15, 578 (1955).Google Scholar

27 Davies, R. D., Monthly Notices Roy. Astron. Soc. 116, 443 (1956).CrossRefGoogle Scholar

28 Whipple, F. L., Harvard Obs. Monographs No. 7, 109 (1948).Google Scholar

29 Schatzman, E., Ann. astrophys. 13, 367 (1950).Google Scholar

30 Oort, T. H. and van de Hulst, H. C., Bull. Astron. Inst. Neth. 10, 187 (No. 376) (1948).Google Scholar

31 Strömgren, B., Astrophys. J. 108, 242 (1948).Google Scholar

32 ter Haar, D., Z. Astrophys. 32, 251 (1953).Google Scholar

33 Oort, J. H., Bull. Astron. Inst. Neth. 12, 177 (No. 455) (1954).Google Scholar

34 Johnson, H. M., Astrophys. J. 117, 235 (1953).CrossRefGoogle Scholar

35 Shajn, G., Trans. Intern. Astron. Union 9, 504 (1957).Google Scholar

36 Gum, C. S., Observatory 76, 150 (1956).Google Scholar

37 Johnson, H. M., Astrophys. J. 121, 604 (1955).Google Scholar

38 Morgan, , Strömgren, , and Johnson, , Astrophys. J. 121, 611 (1955).CrossRefGoogle Scholar

39 Münch, L., Bol. Tonanzintla y Tacubaya No. 13, 28 (1955).Google Scholar

40 Pottasch, S., Bull. Astron. Soc. Neth. 13, 77 (No. 471) (1956).Google Scholar

41 Strömgren, B., Astrophys. J. 89, 526 (1939).CrossRefGoogle Scholar

42 Shajn, G. A. and Hase, V. F., Astron. Zhur. 30, 135 (1953).Google Scholar

43 Johnson, H. M., Astrophys. J. 124, 90 (1956).Google Scholar

44 Oort, J. H., Monthly Notices Roy. Astron. Soc. 106, 159 (1946).Google Scholar

45 Reference 18, p. 106.Google Scholar

46 Minkowski, R., Revs. Modern Phys. 30, 1048 (1958), this issue.CrossRefGoogle Scholar

47 Pottasch, S., Bull. Astron. Inst. Neth. 14, 29 (No. 482) (1958).Google Scholar

48 Osterbrock, D. E., Astrophys. J. 125, 622 (1957).Google Scholar

49 Poveda, A., Bol. Tonanzintla y Tacubaya No. 15 (1956).Google Scholar

50 Agekian, T. A., Astron. Zhur. 32, 416 (1955).Google Scholar

51 Bok, B. J. and Reilly, E. F., Astrophys. J. 105, 255 (1947).CrossRefGoogle Scholar

52 Bok, B. J., Harvard Obs. Monographs No. 7, Centennial Symposia, 53 (1948).Google Scholar

53 Fleischer, R. and Conti, P. S., Astrophys. J. 61, 4 (1956).Google Scholar

54 Reference 18, p. 18.Google Scholar

55 Thackeray, A. D., Monthly Notices Roy. Astron. Soc. 110, 524 (1950).Google Scholar