Stormy weather in galaxy clusters

Science

Volumn 280, Issue 5362, 1998, Pages 400-404

  Burns, Jack O ^a  

^a UNIVERSITY OF MISSOURI   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ASTRONOMY; COSMOS; PRIORITY JOURNAL; RADIOFREQUENCY RADIATION; REVIEW; SPECTRUM; WEATHER; X RAY PICTURE;

EID: 0032540470     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.280.5362.400     Document Type: Review

References (80)

1. 0 is the Hubble constant).
2. 0 < 1) the universe will continue monotonic expansion.
3. 0 because clusters must form earlier [that is, at larger redshifts or look-back times (5)] in a low density universe. Estimates of the density parameter from cluster properties can be found, for example, in D. Richstone, A. Loeb, E. L. Turner, Astrophys. J. 393, 477 (1992); A. Evrard, J. Mohr, D. Fabricant, M. Geller, Astrophys. J. Lett. 419, L9 (1993); N. A. Bahcall, X. Fan, R. Cen, ibid. 485, L53 (1997); J. P. Henry, ibid. 489, L1 (1997); A. E. Evrard, Mon. Not. R. Astron. Soc. 292, 289 (1997).
4. 0 because clusters must form earlier [that is, at larger redshifts or look-back times (5)] in a low density universe. Estimates of the density parameter from cluster properties can be found, for example, in D. Richstone, A. Loeb, E. L. Turner, Astrophys. J. 393, 477 (1992); A. Evrard, J. Mohr, D. Fabricant, M. Geller, Astrophys. J. Lett. 419, L9 (1993); N. A. Bahcall, X. Fan, R. Cen, ibid. 485, L53 (1997); J. P. Henry, ibid. 489, L1 (1997); A. E. Evrard, Mon. Not. R. Astron. Soc. 292, 289 (1997).
5. 0 because clusters must form earlier [that is, at larger redshifts or look-back times (5)] in a low density universe. Estimates of the density parameter from cluster properties can be found, for example, in D. Richstone, A. Loeb, E. L. Turner, Astrophys. J. 393, 477 (1992); A. Evrard, J. Mohr, D. Fabricant, M. Geller, Astrophys. J. Lett. 419, L9 (1993); N. A. Bahcall, X. Fan, R. Cen, ibid. 485, L53 (1997); J. P. Henry, ibid. 489, L1 (1997); A. E. Evrard, Mon. Not. R. Astron. Soc. 292, 289 (1997).
6. 0 because clusters must form earlier [that is, at larger redshifts or look-back times (5)] in a low density universe. Estimates of the density parameter from cluster properties can be found, for example, in D. Richstone, A. Loeb, E. L. Turner, Astrophys. J. 393, 477 (1992); A. Evrard, J. Mohr, D. Fabricant, M. Geller, Astrophys. J. Lett. 419, L9 (1993); N. A. Bahcall, X. Fan, R. Cen, ibid. 485, L53 (1997); J. P. Henry, ibid. 489, L1 (1997); A. E. Evrard, Mon. Not. R. Astron. Soc. 292, 289 (1997).
7. 0 because clusters must form earlier [that is, at larger redshifts or look-back times (5)] in a low density universe. Estimates of the density parameter from cluster properties can be found, for example, in D. Richstone, A. Loeb, E. L. Turner, Astrophys. J. 393, 477 (1992); A. Evrard, J. Mohr, D. Fabricant, M. Geller, Astrophys. J. Lett. 419, L9 (1993); N. A. Bahcall, X. Fan, R. Cen, ibid. 485, L53 (1997); J. P. Henry, ibid. 489, L1 (1997); A. E. Evrard, Mon. Not. R. Astron. Soc. 292, 289 (1997).
8. 0 < 1, the universe is open and will expand forever (48).
9. 0 = 0.2), the fraction of blue galaxies is measured to be ∼80% of the observed galaxies in each cluster [K. Rakos and J. Schombert, Astrophys. J. 439, 47 (1995)]. This diminishes to ∼20% for Δt = 3 Gy (z = 0.4) and ∼4% at present [H. Butcher and A. Oemler, ibid. 285, 426 (1984). The trend is generally known as the Butcher-Oemler effect].
10. R. J. Lavery and J. P. Henry, Astrophys. J. 330, 596 (1988); A. Dressler et al., ibid. 430, 107 (1994); W. Couch et al., ibid., p. 121.
11. R. J. Lavery and J. P. Henry, Astrophys. J. 330, 596 (1988); A. Dressler et al., ibid. 430, 107 (1994); W. Couch et al., ibid., p. 121.
12. R. J. Lavery and J. P. Henry, Astrophys. J. 330, 596 (1988); A. Dressler et al., ibid. 430, 107 (1994); W. Couch et al., ibid., p. 121.
13. B. Moore et al., Nature 379, 613 (1996); D. C. Koo et al., Astrophys. J. Lett. 478, 49 (1997).
14. B. Moore et al., Nature 379, 613 (1996); D. C. Koo et al., Astrophys. J. Lett. 478, 49 (1997).
15. M. Loewenstein and R. Mushotzky, Astrophys. J. 466, 695 (1996).
16. p is the average gas particle mass (0.6 times the proton mass for fully ionized gas), ρ is the gas density, k is the Boltzmann constant, and T is the gas temperature [C. Sarazin, Rev. Mod. Phys. 58, 1 (1986)]. However, the presence of dynamically important substructure in a cluster can produce significant errors in masses estimated with these techniques [(30); C. Bird, Astron. J. 109, 920 (1996); C. Balland and A. Blanchard, ibid. 487, 33 (1997)].
17. p is the average gas particle mass (0.6 times the proton mass for fully ionized gas), ρ is the gas density, k is the Boltzmann constant, and T is the gas temperature [C. Sarazin, Rev. Mod. Phys. 58, 1 (1986)]. However, the presence of dynamically important substructure in a cluster can produce significant errors in masses estimated with these techniques [(30); C. Bird, Astron. J. 109, 920 (1996); C. Balland and A. Blanchard, ibid. 487, 33 (1997)].
18. p is the average gas particle mass (0.6 times the proton mass for fully ionized gas), ρ is the gas density, k is the Boltzmann constant, and T is the gas temperature [C. Sarazin, Rev. Mod. Phys. 58, 1 (1986)]. However, the presence of dynamically important substructure in a cluster can produce significant errors in masses estimated with these techniques [(30); C. Bird, Astron. J. 109, 920 (1996); C. Balland and A. Blanchard, ibid. 487, 33 (1997)].
19. p is the average gas particle mass (0.6 times the proton mass for fully ionized gas), ρ is the gas density, k is the Boltzmann constant, and T is the gas temperature [C. Sarazin, Rev. Mod. Phys. 58, 1 (1986)]. However, the presence of dynamically important substructure in a cluster can produce significant errors in masses estimated with these techniques [(30); C. Bird, Astron. J. 109, 920 (1996); C. Balland and A. Blanchard, ibid. 487, 33 (1997)].
20. J. Miralda-Escudé and A. Babul, Astrophys. J. 449, 18 (1995); S. W. Allen, A. C. Fabian, J.-P. Kneib, Mon. Not. R. Astron. Soc. 279, 615 (1996). Unlike the methods discussed in (9), mass estimates with gravitational lenses do not require clusters to be free of substructure or in hydrostatic and virial equilibrium.
21. J. Miralda-Escudé and A. Babul, Astrophys. J. 449, 18 (1995); S. W. Allen, A. C. Fabian, J.-P. Kneib, Mon. Not. R. Astron. Soc. 279, 615 (1996). Unlike the methods discussed in (9), mass estimates with gravitational lenses do not require clusters to be free of substructure or in hydrostatic and virial equilibrium.
22. S. D. M. White et al., Nature 366, 429 (1993).
23. A. Loeb and S. Mao, Astrophys. J. 435, 109 (1994).
24. J. J. Mohr, D. G. Fabricant, M. J. Geller, ibid. 413, 492 (1993); J. J. Mohr, A. E. Evrard, D. G. Fabricant, M. J. Geller, ibid. 447, 8 (1995).
25. J. J. Mohr, D. G. Fabricant, M. J. Geller, ibid. 413, 492 (1993); J. J. Mohr, A. E. Evrard, D. G. Fabricant, M. J. Geller, ibid. 447, 8 (1995).
26. C. Jones and W. Forman, in Clusters and Superclusters of Galaxies, A. Fabian, Ed. (Kluwer, Dordrecht, Netherlands, 1992), pp. 49-70; C. Bird, Astron. J. 107, 1637 (1994).
27. C. Jones and W. Forman, in Clusters and Superclusters of Galaxies, A. Fabian, Ed. (Kluwer, Dordrecht, Netherlands, 1992), pp. 49-70; C. Bird, Astron. J. 107, 1637 (1994).
28. J. O. Burns, G. Rhee, F. Owen, J. Pinkney, Astrophys. J. 423, 94 (1994).
29. S. D. M. White, U. G. Briel, J. P. Henry, Mon. Not. R. Astron. Soc. 261, L18 (1993).
30. Doppler shifts of spectral lines in galaxy spectra are used to measure galaxy velocities. [J. M. Hill and W. R. Oegerle, Astron. J. 106, 831 (1993)].
31. T. C. Beers, K. Flynn, K. Gebhardt, ibid. 100, 32 (1990); J. Pinkney, K. Roettiger, J. O. Burns, C. Bird, Astrophys. J. Suppl. 104, 1 (1996).
32. T. C. Beers, K. Flynn, K. Gebhardt, ibid. 100, 32 (1990); J. Pinkney, K. Roettiger, J. O. Burns, C. Bird, Astrophys. J. Suppl. 104, 1 (1996).
33. J. Trümper, Science 260, 1769 (1993); W. Voges, in Proceedings of the European International Space Year Conference, T. D. Guyenne and J. J. Hunt, Eds. (ESA, Noordwijk, Netherlands, 1992), p. 9.
34. J. Trümper, Science 260, 1769 (1993); W. Voges, in Proceedings of the European International Space Year Conference, T. D. Guyenne and J. J. Hunt, Eds. (ESA, Noordwijk, Netherlands, 1992), p. 9.
35. D. S. Davis and R. F. Mushotzky, Astron. J. 105, 409 (1993).
36. X-ray moment analyses of cluster substructure can be found in papers by D. A. Buote and J. C. Tsai [Astrophys. J. 452, 522 (1995); ibid. 458, 27 (1996)]. An example of the wavelet approach to measure substructure is presented in E. Slezak, F. Durret, D. Gerbal, Astron. Astrophys. 108, 1996 (1994).
37. X-ray moment analyses of cluster substructure can be found in papers by D. A. Buote and J. C. Tsai [Astrophys. J. 452, 522 (1995); ibid. 458, 27 (1996)]. An example of the wavelet approach to measure substructure is presented in E. Slezak, F. Durret, D. Gerbal, Astron. Astrophys. 108, 1996 (1994).
38. X-ray moment analyses of cluster substructure can be found in papers by D. A. Buote and J. C. Tsai [Astrophys. J. 452, 522 (1995); ibid. 458, 27 (1996)]. An example of the wavelet approach to measure substructure is presented in E. Slezak, F. Durret, D. Gerbal, Astron. Astrophys. 108, 1996 (1994).
39. J. P. Henry and U. G. Briel, Astrophys. J. Lett. 443, L9 (1995); M. Markevitch et al., ibid. 436, L71 (1994).
40. J. P. Henry and U. G. Briel, Astrophys. J. Lett. 443, L9 (1995); M. Markevitch et al., ibid. 436, L71 (1994).
41. K. Roettiger, J. O. Burns, J. Pinkney, Astrophys. J. 453, 634 (1995).
42. J. Pinkney, J. O. Burns, J. M. Hill, Astron. J. 108, 2031 (1994); P. L. Gómez, M. J. Ledlow, J. O. Burns, J. Pinkney, J. M. Hill, ibid. 114, 1711 (1997).
43. J. Pinkney, J. O. Burns, J. M. Hill, Astron. J. 108, 2031 (1994); P. L. Gómez, M. J. Ledlow, J. O. Burns, J. Pinkney, J. M. Hill, ibid. 114, 1711 (1997).
44. Two approaches have been used to model the gas dynamics in clusters: smooth particle hydrodynamics (SPH) and Eulerian schemes. SPH uses a gridless method similar to N-body techniques that affords high spatial dynamic range but less accurate handling of shock waves [A. E. Evrard, Astrophys. J. 363, 349 (1990)]. Eulerian codes use numerical meshes to solve the fluid conservation equations with accurate shock-tracking, but with traditionally lower spatial fidelity [K. Roettiger, C. Loken, J. O. Bums, Astrophys. J. Suppl. 109, 307 (1997); S. Schindler and E. Müller, Astron. Astrophys. 272, 137 (1993)]. This limitation for Eulerian codes is now being overcome with adaptive grid methods (26), which use a hierarchy of grid sizes that depend on the density of gas (as in Fig. 3).
45. Two approaches have been used to model the gas dynamics in clusters: smooth particle hydrodynamics (SPH) and Eulerian schemes. SPH uses a gridless method similar to N-body techniques that affords high spatial dynamic range but less accurate handling of shock waves [A. E. Evrard, Astrophys. J. 363, 349 (1990)]. Eulerian codes use numerical meshes to solve the fluid conservation equations with accurate shock-tracking, but with traditionally lower spatial fidelity [K. Roettiger, C. Loken, J. O. Bums, Astrophys. J. Suppl. 109, 307 (1997); S. Schindler and E. Müller, Astron. Astrophys. 272, 137 (1993)]. This limitation for Eulerian codes is now being overcome with adaptive grid methods (26), which use a hierarchy of grid sizes that depend on the density of gas (as in Fig. 3).
46. Two approaches have been used to model the gas dynamics in clusters: smooth particle hydrodynamics (SPH) and Eulerian schemes. SPH uses a gridless method similar to N-body techniques that affords high spatial dynamic range but less accurate handling of shock waves [A. E. Evrard, Astrophys. J. 363, 349 (1990)]. Eulerian codes use numerical meshes to solve the fluid conservation equations with accurate shock-tracking, but with traditionally lower spatial fidelity [K. Roettiger, C. Loken, J. O. Bums, Astrophys. J. Suppl. 109, 307 (1997); S. Schindler and E. Müller, Astron. Astrophys. 272, 137 (1993)]. This limitation for Eulerian codes is now being overcome with adaptive grid methods (26), which use a hierarchy of grid sizes that depend on the density of gas (as in Fig. 3).
47. M. L. Norman, in Proceedings of the Twelfth Kingston Meeting on Theoretical Astrophysics: Computational Astrophysics, Astronomical Society of the Pacific (ASP), Halifax, 1997, D. A. Clarke and M. J. West, Eds. (ASP, San Francisco, 1997), p. 363.
48. A. L. Melon et al., Phys. Rev. Lett. 51, 935 (1983); A. L. Melott and S. F. Shandarin, Astrophys. J. 410, 469 (1993).
49. A. L. Melon et al., Phys. Rev. Lett. 51, 935 (1983); A. L. Melott and S. F. Shandarin, Astrophys. J. 410, 469 (1993).
50. A. C. Fabian and S. J. Daines, Mon. Not. R. Astron. Soc. 252, 17p (1991); A. Edge, A. Stewart, A. C. Fabian, ibid. 258, 177 (1992); C. Loken, A. Klypin, J. Burns, G. Bryan, M. Norman, in preparation.
51. A. C. Fabian and S. J. Daines, Mon. Not. R. Astron. Soc. 252, 17p (1991); A. Edge, A. Stewart, A. C. Fabian, ibid. 258, 177 (1992); C. Loken, A. Klypin, J. Burns, G. Bryan, M. Norman, in preparation.
52. A. C. Fabian and S. J. Daines, Mon. Not. R. Astron. Soc. 252, 17p (1991); A. Edge, A. Stewart, A. C. Fabian, ibid. 258, 177 (1992); C. Loken, A. Klypin, J. Burns, G. Bryan, M. Norman, in preparation.
53. K. Roettiger, J. Burns, C. Loken, Astrophys. J. Lett. 407, L53 (1993).
54. _, Astrophys. J. 473, 651 (1996).
55. 1/2) and temperature maps will show significant variations (that is, substructure) between regions of shocked and unshocked gas.
56. M. Ledlow, in The Second Stromlo Symposium: The Nature of Elliptical Galaxies, M. Arnaboldi, G. S. Da Costa, P. Saha, Eds. (ASP, San Francisco, 1997), vol. 116, p. 421.
57. -1/2 >1000, where v is the electron velocity and c is the speed of light] gyrate within magnetic fields (typically ∼10 μG) in the plasma to produce radio emission by synchrotron radiation. [For more details on extended radio sources, see, for example, J. O. Burns, M. L. Norman, D. A. Clarke, Science 253, 522 (1991).]
58. J.-H. Zhao, J. O. Burns, F. N. Owen, Astron. J. 98, 64 (1989); F. N. Owen and M. Ledlow, Astrophys. J. Suppl. 108, 41 (1997).
59. J.-H. Zhao, J. O. Burns, F. N. Owen, Astron. J. 98, 64 (1989); F. N. Owen and M. Ledlow, Astrophys. J. Suppl. 108, 41 (1997).
60. ICM ≪ 1), the collimated plasma flow in U-shaped sources must experience transverse winds with typical velocities of ≳1000 km/s to bend to their observed curvature, assuming typical jet and ICM properties. Thus, the observed jet curvature can be used to constrain the relative velocity of the radio source with respect to the surrounding gas.
61. C. Loken et al., Astrophys. J. 445, 80 (1995).
62. P. L. Gómez et al., ibid. 474, 580 (1997); J. Pinkney et al., ibid. 416, 36 (1993).
63. P. L. Gómez et al., ibid. 474, 580 (1997); J. Pinkney et al., ibid. 416, 36 (1993).
64. M. Bliton, E. Rizza, J. O. Burns, F. N. Owen, M. Ledlow, Mon. Not. R. Astron. Soc., in press.
65. T. W. Jones and F. N. Owen, Astrophys. J. 234, 818 (1979); M. C. Begelman, M. J. Rees, R. D. Blandford, Nature 279, 770 (1979).
66. T. W. Jones and F. N. Owen, Astrophys. J. 234, 818 (1979); M. C. Begelman, M. J. Rees, R. D. Blandford, Nature 279, 770 (1979).
67. R. J. Hanisch, Astron. J. 85, 1565 (1980); K.-T. Kim et al., Astrophys. J. 355, 29 (1990).
68. R. J. Hanisch, Astron. J. 85, 1565 (1980); K.-T. Kim et al., Astrophys. J. 355, 29 (1990).
69. J. O. Burns et al., Astrophys. J. 446, 583 (1995); P. C. Tribble, Mon. Not. R. Astron. Soc. 263, 31 (1993).
70. J. O. Burns et al., Astrophys. J. 446, 583 (1995); P. C. Tribble, Mon. Not. R. Astron. Soc. 263, 31 (1993).
71. J. O. Burns, K. Roettiger, M. Ledlow, A. Klypin, Astrophys. J. Lett. 427, L87 (1994).
72. Relativistic electrons, which are responsible for producing the synchrotron radio emission, cannot travel across the megaparsec-diameter halos within their radiative lifetime, even traveling at velocities of nearly c. Thus, some form of in situ reacceleration is required.
73. A Fermi-like mechanism involving shocks or turbulence is most often proposed for in situ reacceleration of electrons [J. A. Eilek and P. E. Hughes, in Astrophysical Jets, P. E. Hughes, Ed. (Cambridge Univ. Press, Cambridge, 1990), pp. 428-483].
74. D. S. De Young, Astrophys. J. 241, 81 (1980).
75. R. Cen and J. P. Ostriker, ibid. 417, 404 (1993); A. Evrard, ibid. 437, 564 (1994).
76. R. Cen and J. P. Ostriker, ibid. 417, 404 (1993); A. Evrard, ibid. 437, 564 (1994).
77. K. Roettiger and J. M. Stone, Bull. Am. Astron. Soc., 29, 1302 (1997).
78. P. J. E. Peebles, Principles of Physical Cosmology (Princeton Univ. Press, Princeton, NJ, 1993).
79. K. Roettiger, J. Stone, R. Mushotzky, Astrophys. J. 493, 62 (1998).
80. Supported in part by NSF grants AST-9317596 and AST-9896039 and NASA grant NAGW-3152. I am indebted to my collaborators who contributed to the work described here, including M. Bliton, G. Bryan, P. Gómez, J. Hill, A. Klypin, M. Ledlow, C. Loken, M. Norman, F. Owen, J. Pinkney, E. Rizza, K. Roettiger, W. Voges, and R. A. White. I particularly acknowledge M. Ledlow, P. Gómez, C. Loken, G. Bryan, and K. Roettiger for their help with Figs. 1 through 4. I also thank A. Melott, S. Shandarin, and J. P. Henry for their useful comments on the text.