Article
Lick slit spectra of thirtyeight objective prism quasar candidates and low metallicity halo stars
The Astronomical Journal (Impact Factor: 4.97). 09/1993; DOI: 10.1086/116652
Source: arXiv

Article: A UNIFORM ANALYSIS OF THE LY� FOREST AT Z=0  5: I. THE SAMPLE AND DISTRIBUTION OF CLOUDS AT Z > 1.7
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ABSTRACT: We present moderate resolution data for 39 quasistellar objects (QSOs) at z � 2 obtained at the Multiple Mirror Telescope. These data are combined with spectra of comparable resolution of 60 QSOs with redshifts greater than 1.7 found in the literature to investigate the distribution of Lyforest lines in redshift and equivalent width. We find a value for , the parameter describing the number distribution of Lyforest lines in redshift, of 1.88±0.22 for lines stronger than a rest equivalent width of 0.32 ûA, in good agreement with some previous studies. The KolmogorovSmirnov test was applied to the data and it is found that this single power law is a good fit over the relevant redshift ranges. Simulations of the Lymanforest were performed to determine the completeness of the line lists and to test how well the analysis recovers the underlying line statistics, given this level of completeness.The Astrophysical Journal Supplement Series 09/2000; 130(1). · 16.24 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the possible occurrence of extra spatial dimensions (D = 3+epsilon) in the early universe. A detailed calculation is presented which shows that the crucial signal is the apparent inequality of the cosmological Zterm between matching Lyman alpha (Ly{alpha}) and Lyman beta (Ly{beta}) spectral lines, both emission and absorption, when using the present epoch (laboratory) wavelengths. We present preliminary upper limits to the value of epsilon, to be improved by direct, more careful analysis of the spectra. We take catalogued quasar Ly{alpha} forest data and perform Student's ttest to determine whether we should reject the null hypothesis (no fractal dimensions). Finally, a chi^{2} analysis is done for fitting epsilon in the early universe. The statistical tests and experimental data are all consistent with epsilon = 0 for Z < 3.3, but the experimental data support nonzero epsilon values for Z > 4. However, it should be emphasized that the nonzero values of epsilon found for Z > 4 may be due to undiscovered systematic errors in the original data. Comment: 9 pages, 1 figure. To be published in Physics Letters BPhysics Letters B 12/1999; · 4.57 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A thorough search for blueshifts in Quasi Stellar Objects (QSOs) has not yet been made, although possibilities have been suggested. The main reason appears to be the usual practice of identifying observed lines always with search lines in the UV/blue region, and ignoring the red/IR region. We demonstrate that sufficient search lines are available for blueshift measurements in QSOs, and show that within observational errors observed emission lines can be identified with alternative lines at higher wavelengths, that are blueshifted to the observing window. Blueshifts are calculated with the same or higher levels of accuracy as redshifts. Consideration of equivalent widths demonstrates further that blueshift identifications of observed lines are more convincing than redshift identifications.Physica Scripta 03/2006; 63(5):425. · 1.03 Impact Factor
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