Neutral hydrogen absorption in the spectra of quasi-stellar objects - A search for absorption due to clusters of galaxies

1978 ◽  
Vol 223 ◽  
pp. 740 ◽  
Author(s):  
B. M. Peterson
Keyword(s):  
Hydrogen Absorption ◽  
Neutral Hydrogen ◽  
Clusters Of Galaxies ◽  
Stellar Objects ◽  
Quasi Stellar Objects

Are Some Quasi-Stellar Objects Associated with Clusters of Galaxies?

1969 ◽  
Vol 157 ◽  
pp. L77 ◽  
Author(s):  
John N. Bahcall ◽  
Maarten Schmidt ◽  
James E. Gunn
Keyword(s):  
Clusters Of Galaxies ◽  
Stellar Objects ◽  
Quasi Stellar Objects

scholarly journals A Master List of Non-Stellar Objects

1977 ◽  
Vol 35 ◽  
pp. 167-169
Author(s):  
ROBERT S. DIXON
Keyword(s):  
Globular Clusters ◽  
Reference Data ◽  
Clusters Of Galaxies ◽  
Stellar Objects ◽  
Readable Form ◽  
Practical Standpoint ◽  
Order Of Magnitude ◽  
Quasi Stellar Objects ◽  
Basic Reference ◽  
Scientists And Engineers

It has been nearly 70 years since Dreyer completed his famous NGC and IC compendia of all the 13,000 non-stellar objects known in his time. Since then, the number of these objects known has increased by an order of magnitude, but this knowledge is scattered throughout the astronomical literature in such a way that it 1s nearly inaccessible from a practical standpoint to any individual.The present work is an amalgamation of all known catalogs of non-stellar objects, in a uniform, easily readable form. It is Intended not only for astronomers, but also for scientists and engineers in other fields who have need for rapid access to this basic reference data. The types of objects included are galaxies (including both normal and all specialized types such as interacting, peculiar, dwarf, Seyfert, etc.), clusters of galaxies, nebulae of all kinds (planetary, reflection, emission, absorption, etc.), blue objects, groups of stars (open and globular clusters, associations, rings, chains, etc.), quasi-stellar objects, super-novae and others. The Information given for each object includes name, 1950.0 position, angular diameter in arcseconds, magnitude, description, and original reference. A portion of the work is shown in Figure 1. Approximately 185,000 listings appear in the full master 11st.

Absorption by neutral hydrogen and ionized magnesium in quasi-stellar objects and BL Lacertae objects

1977 ◽  
Vol 218 ◽  
pp. 605 ◽  
Author(s):  
B. M. Peterson ◽  
P. A. Strittmatter ◽  
R. E. Williams ◽  
G. D. Coleman
Keyword(s):  
Neutral Hydrogen ◽  
Bl Lacertae Objects ◽  
Stellar Objects ◽  
Ionized Magnesium ◽  
Bl Lacertae ◽  
Quasi Stellar Objects

Relative Correlation of - and Small-Redshift Quasi-Stellar Objects with Clusters of Galaxies

1971 ◽  
Vol 166 ◽  
pp. L77 ◽  
Author(s):  
John N. Bahcall ◽  
Neta A. Bahcall ◽  
G. R. Burbidge
Keyword(s):  
Clusters Of Galaxies ◽  
Stellar Objects ◽  
Quasi Stellar Objects

scholarly journals The influence of metagalactic ultraviolet background fluctuations on the high-redshift Lyα forest

2019 ◽  
Vol 491 (4) ◽  
pp. 4884-4893 ◽  
Author(s):  
Avery Meiksin
Keyword(s):  
Luminosity Function ◽  
High Redshift ◽  
Spatial Coherence ◽  
Neutral Hydrogen ◽  
Line Of Sight ◽  
Analytic Model ◽  
Broad Distribution ◽  
Stellar Objects ◽  
Quasi Stellar Objects ◽  
Autocorrelation Length

ABSTRACT Under the assumption that galaxies and quasi-stellar objects (QSOs) dominate the metagalactic ultraviolet (UV) background, it is shown that at high redshifts, fluctuations in the UV background are dominated by QSO shot noise and have an autocorrelation length of a few to several comoving Mpcs, depending on the bright end of the QSO luminosity function. The correlations create long-range spatial coherence in the neutral hydrogen fraction. Using a semi-analytic model, it is demonstrated that the coherence may account for the broad distribution in effective optical depths measured in the Lyα forest spectra of background QSOs, for line-of-sight segments of comoving length $50\, h^{-1}$ Mpc at redshifts 5 < z < 6. Capturing the fluctuations in a numerical simulation requires a comoving box size of ∼1 Gpc, although a box half this size may be adequate if sufficient random realizations of the QSO population are performed.

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