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The All-Sky Extragalactic X-Ray Foreground

Published online by Cambridge University Press:  12 April 2016

Elihu Boldt
Elihu Boldt*
Affiliation:
NASA/Goddard Space Flight Center, Greenbelt, MD 20771

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Observations of galaxies in the IR and optical (Lynden-Bell et al. 1989) suggest that the 600 km/s peculiar velocity of the LG (Local Group of galaxies) arises mainly from a foreground of anisotropically distributed mass within z = 0.013 (i.e., HR < 4000 km/s). Since the X-ray luminosity of bright extragalactic X-ray sources provides a good mass measure of the radiating objects involved and can be observed relatively free of galactic obscuration effects, such sources are likely candidates for serving as reliable tracers of the total underlying mass (i.e., dark as well as visible) responsible for the acceleration of the LG. In this connection, we note that the local gravitational dipole implied by the fifty X-ray brightest clusters of galaxies at z > 0.013 considered by Lahav et al. (1989) is relatively small compared with that inferred from the only three clusters at lower redshifts. Since the local space density of AGN (Active Galactic Nuclei) is about two orders of magnitude greater than rich clusters, however, such compact sources have the potential of providing a vastly improved statistical sample for tracing mass in the low-redshift region of particular interest. Furthermore, recent dipole analysis of the X-ray flux from bright AGN observed with HEAO-1 A2 indicates that they are indeed strong tracers of this matter (Miyaji and Boldt 1990). The implications of this for the very pronounced large-scale foreground anisotropies to be measured via low-redshift AGN resolved in more sensitive all-sky surveys are explored.

Type
V. Long Term Future Issues
Information
International Astronomical Union Colloquium , Volume 123: Observatories in Earth Orbit and Beyond , 1990 , pp. 451 - 455
Copyright
Copyright © Kluwer 1990

References

Bahcall, N.: 1988, Ann. Rev. Astron. Astrophys. 26, 631 Google Scholar
Compton, A. and Getting, I.: 1935, Phys. Rev. 47, 817 Google Scholar
Goicoechea, L., and Martin-Mirones, J.: 1990, MNRAS, in pressGoogle Scholar
Helfand, D. et al.: 1989, Bull. AAS 121, 1220 Google Scholar
Jahoda, K. and Mushotzky, M.: 1989, Astroph. J. 346, 638 Google Scholar
Lahav, O., Rowan-Robinson, M. and Lynden-Bell, D.: 1988, MNRAS 234, 677 CrossRefGoogle Scholar
Lahav, O., Edge, A., Fabian, A. and Putney, A.: 1989, MNRAS 238, 881 Google Scholar
Lynden-Bell, D. et al.: 1988, Astroph. J. 326, 19 Google Scholar
Lynden-Bell, D., Lahav, O. and Burstein, D.: 1989, MNRAS 241, 325 Google Scholar
McKee, J. et al.: 1980, Astroph. J. 242, 843 Google Scholar
Miyaji, T. and Boldt, E.: 1990, Astroph. J.(Letters), in pressGoogle Scholar
Peebles, P.J.E.: 1980, The Large Scale Structure of the Universe, Princeton University Press, Priceton Google Scholar
Persic, M. et al.: 1989, Astroph. J. 344, 125 Google Scholar
Shafer, R.: 1983, PhD thesis, University of Maryland, NASA TM 85029Google Scholar
Wandel, A. and Mushotzky, R.: 1986, Astroph. J. 306, L61 CrossRefGoogle Scholar