Astronomy and Astrophysics – Astrophysics
Scientific paper
Apr 1980
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1980apj...237..355s&link_type=abstract
Astrophysical Journal, Part 1, vol. 237, Apr. 1, 1980, p. 355-362.
Astronomy and Astrophysics
Astrophysics
18
Cosmology, Intergalactic Media, Photoionization, Quasars, Cosmic Plasma, Emission Spectra
Scientific paper
This investigation employs a computer code, initially constructed for modeling the evolution of a hot dense intergalactic medium (IGM), to study some properties of a cold dense IGM photoionized by QSOs. Within the observational constraints set by flux measurements in the far-ultraviolet, night sky brightness, and hard X-ray region, and the optical depth limits on various QSO spectra, it determines some allowable scenarios for a range of QSO spectral indices (alpha) and cutoff energies. With H(0) = 50 km/s-Mpc, closure density of an IGM (composed of H and He in their cosmic ratio) is possible only if alpha is greater than or equal to 0.1, a circumstance not likely to prevail; the most probable value, alpha = -0.7, implies an upper limit density about 0.35 of closure, which is somewhat larger than previous estimates. These estimates are substantially independent of whether or not QSOs produce the observed diffuse extragalactic X-ray background; such QSO spectral details are critical, however, in determining the ionization of heavy elements that are expected to contaminate a pure primeval plasma.
No associations
LandOfFree
Cold dense photoionized universes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Cold dense photoionized universes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cold dense photoionized universes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1697762