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91.
Douglas S. Hall Gregory W. Henry Dietmar Böhme Peter A. Brooks Sandy Chang Ales Dolzan George L. Fortier Robert E. Fried Russell M. Genet Bruce S. Grim James Hannon Darrel B. Hoff Kevin Krisciunas Howard J. Landis Howard P. Louth Larry P. Lovell Paul Nielsen Bobby E. Powell Harry D. Powell Don Pray Thomas R. Renner Charles W. Rogers Stephen Shervais Douglas M. Slauson Samuel Slote Harold J. Stelzer Arthur J. Stokes Jack C. Troeger Louis C. Turner Norman F. Wasson Kenneth W. Zeigler 《Journal of Astrophysics and Astronomy》1991,12(4):281-287
We present photoelectric photometry of λ And never before published, obtained between February 1982 and December 1990 at 29
different observatories. Then we combine it with all other photometry available to us (previously published, contained in
the I.A.U. Commission 27 Archives, and obtained with the Vanderbilt 16-inch automatic telescope but not yet published), to
yield a 14.8-year data base. Analysis reveals a long-term cycle in mean brightness, with a full range of 0m.15 and a period of 11.4 ± 0.4 years. Because most of our new photometry was concentrated in the 1983-84 observing season,
we analyze that one well-defined light curve with a two-spot model. Spot A keeps a 0m.04 amplitude throughout four rotation cycles whereas the amplitude of spot B diminishes from 0m.09 down almost to 0m.03. The spot rotation periods were 55d.9 ± 0d.6 and 520d.8 ± 1d.0, respectively. 相似文献
92.
Howell G.M. Edwards Caroline D. Moody Susana E. Jorge Villar Michael J. Russell 《Icarus》2005,175(2):372-381
Raman spectra of an extremophile cyanobacterial colony in hydromagnesite from Lake Salda in Turkey have revealed a biogeological modification which is manifest as aragonite in the stratum associated with the colony. The presence of key spectral biomarkers of organic protectant molecules such as β-carotene and scytonemin indicate that the survival strategy of the cyanobacteria is significantly one of UV-radiation protection. The terrestrial location of this extremophile is worthy of consideration further because of its possible putative link with the “White Rock” formations in Sabaea Terra and Juventae Chasma on Mars. 相似文献
93.
D. Heath Jones Will Saunders Matthew Colless Mike A. Read Quentin A. Parker Fred G. Watson Lachlan A. Campbell Daniel Burkey Thomas Mauch Lesa Moore Malcolm Hartley Paul Cass Dionne James Ken Russell Kristin Fiegert John Dawe John Huchra Tom Jarrett Ofer Lahav John Lucey Gary A. Mamon Dominique Proust Elaine M. Sadler Ken-ichi Wakamatsu 《Monthly notices of the Royal Astronomical Society》2004,355(3):747-763
94.
95.
The 2dF Galaxy Redshift Survey: the bJ -band galaxy luminosity function and survey selection function
Peder Norberg Shaun Cole Carlton M. Baugh Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Nicholas J. G. Cross Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,336(3):907-931
96.
Peder Norberg Carlton M. Baugh Ed Hawkins Steve Maddox John A. Peacock Shaun Cole Carlos S. Frenk Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Darren Madgwick Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2001,328(1):64-70
We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift surveys used to address this issue. We measure the projected two-point correlation function of galaxies in a series of volume-limited samples. The projected correlation function is free from any distortion of the clustering pattern induced by peculiar motions and is well described by a power law in pair separation over the range . The clustering of galaxies in real space is well-fitted by a correlation length and power-law slope . The clustering amplitude increases slowly with absolute magnitude for galaxies fainter than M *, but rises more strongly at higher luminosities. At low luminosities, our results agree with measurements from the Southern Sky Redshift Survey 2 by Benoist et al. However, we find a weaker dependence of clustering strength on luminosity at the highest luminosities. The correlation function amplitude increases by a factor of 4.0 between and −22.5, and the most luminous galaxies are 3.0 times more strongly clustered than L * galaxies. The power-law slope of the correlation function shows remarkably little variation for samples spanning a factor of 20 in luminosity. Our measurements are in very good agreement with the predictions of the hierarchical galaxy formation models of Benson et al. 相似文献
97.
Groundwaters feeding travertine‐depositing rivers of the northeastern segment of the Barkly karst (NW Queensland, Australia) are of comparable chemical composition, allowing a detailed investigation of how the rate of downstream chemical evolution varies from river to river. The discharge, pH, temperature, conductivity and major‐ion concentrations of five rivers were determined by standard field and laboratory techniques. The results show that each river experiences similar patterns of downstream chemical evolution, with CO2 outgassing driving the waters to high levels of calcite supersaturation, which in turn leads to widespread calcium carbonate deposition. However, the rate at which the waters evolve, measured as the loss of CaCO3 per kilometre, varies from river to river, and depends primarily upon discharge at the time of sampling and stream gradient. For example, Louie Creek (Q = 0·11 m3 s?1) and Carl Creek (Q = 0·50 m3 s?1) have identical stream gradients, but the loss of CaCO3 per kilometre for Louie Creek is twice that of Carl Creek. The Gregory River (Q = 3·07 m3 s?1), O'Shanassy River (Q = 0·57 m3 s?1) and Lawn Hill Creek (Q = 0·72 m3 s?1) have very similar gradients, but the rate of hydrochemical evolution of the Gregory River is significantly less than either of the other two systems. The results have major implications for travertine deposition: the stream reach required for waters to evolve to critical levels of calcite supersaturation will, all others things being equal, increase with increasing discharge, and the length of reach over which travertine is deposited will also increase with increasing discharge. This implies that fossil travertine deposits preserved well downstream of modern deposition limits are likely to have been formed under higher discharge regimes. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
98.
Russell Cannon 《Journal of Astrophysics and Astronomy》1996,17(1-2):1-6
Recent technological advances have led to a dramatic improvement in the quality of photometric and spectroscopic data obtainable
on stars in globular clusters. Evidence from CCD-based colour magnitude diagrams points to clear differences in age between
some clusters. High dispersion spectra show that abundance variations cannot explain the observed differences. In particular,
it seems that NGC 288 must be 2–3 Gyr older than NGC 362. The same spectra show that although there is a spread in some molecular
band strengths in NGC 362, the total C+N+O abundance remains constant, indicating that the material has undergone varying
amounts of nuclear processing. No variations are seen in the abundances of iron group elements. Lower dispersion spectra for
a large sample of faint stars in 47 Tucanae, obtained with a multi-object optical fibre system, show that unevolved main sequence
stars in that cluster share the same CNO variations as the bright giants. The conclusion from all these data is that the intra-cluster
CNO variations are neither truly primordial nor due to evolutionary mixing. It may be that there was a sufficiently extended
period of star formation for material from first generation stars to be used in later generations, or that some pollution
has occurred due to mass loss. Finally, it is noted that if ‘prehistoric’ clusters exist with ages of around 50 Gyr, as hypothesised
in some cosmological models, these should probably still be rather obvious and readily recognised.
Paper presented at the 6th Asian-Pacific Regional Meeting on Astronomy of the International Astronomical Union, India, 1993. 相似文献
99.
Ian Lewis Michael Balogh Roberto De Propris Warrick Couch Richard Bower Alison Offer Joss Bland-Hawthorn Ivan K. Baldry Carlton Baugh Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Nicholas Cross Gavin Dalton Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Edward Hawkins Carole Jackson Ofer Lahav Stuart Lumsden Steve Maddox Darren Madgwick Peder Norberg John A. Peacock Will Percival Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,334(3):673-683
100.
V. R. Eke Carlos S. Frenk Carlton M. Baugh Shaun Cole Peder Norberg John A. Peacock Ivan K. Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto de Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole A. Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve J. Maddox Darren Madgwick Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,355(3):769-784