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861.
862.
A local void and the accelerating Universe 总被引:1,自引:0,他引:1
K. Tomita 《Monthly notices of the Royal Astronomical Society》2001,326(1):287-292
RCW 114 is a filamentary nebula of about 250 arcmin diameter. Based on its large diameter-to-filament-width ratio, the expansion velocity, distance and size of the shell, it has been suggested that RCW 114 is a supernova remnant in its momentum-conserving phase. Confirmation of this identification is important, as the large angular size and extensive optical emission of this object will allow for detailed study to improve our knowledge of supernova remnants and their interaction with the interstellar medium.
We have used the FLAIR instrument on the UK Schmidt Telescope to obtain optical spectra of several filaments in RCW 114. These confirm that the emission is being produced by the interaction of the shock wave of a supernova remnant with the surrounding interstellar medium. We also obtained narrow-band H α +[N ii ] and [S ii ] images to examine the spatial variation in ionization structure. 相似文献
We have used the FLAIR instrument on the UK Schmidt Telescope to obtain optical spectra of several filaments in RCW 114. These confirm that the emission is being produced by the interaction of the shock wave of a supernova remnant with the surrounding interstellar medium. We also obtained narrow-band H α +[N ii ] and [S ii ] images to examine the spatial variation in ionization structure. 相似文献
863.
Nicholas Cross Simon P. Driver Warrick Couch Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Gavin Dalton Kathryn Deeley Roberto De Propris George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Stephen Moody Peder Norberg John A. Peacock Bruce A. Peterson Ian Price Mark Seaborne Will Sutherland Helen Tadros Keith Taylor 《Monthly notices of the Royal Astronomical Society》2001,324(4):825-841
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Edward Conway Steve Maddox Vivienne Wild John A. Peacock Ed Hawkins Peder Norberg Darren S. Madgwick Ivan K. Baldry Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Bryn Jones Ofer Lahav Ian Lewis Stuart Lumsden Will Percival Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2005,356(2):456-474
We present an analysis of the relative bias between early- and late-type galaxies in the Two-degree Field Galaxy Redshift Survey (2dFGRS) – as defined by the η parameter of Madgwick et al., which quantifies the spectral type of galaxies in the survey. We calculate counts in cells for flux-limited samples of early- and late-type galaxies, using approximately cubical cells with sides ranging from 7 to 42 h −1 Mpc . We measure the variance of the counts in cells using the method of Efstathiou et al., which we find requires a correction for a finite volume effect equivalent to the integral constraint bias of the autocorrelation function. Using a maximum-likelihood technique we fit lognormal models to the one-point density distribution, and develop methods of dealing with biases in the recovered variances resulting from this technique. We then examine the joint density distribution function, f (δE , δL ) , and directly fit deterministic bias models to the joint counts in cells. We measure a linear relative bias of ≈1.3, which does not vary significantly with ℓ. A deterministic linear bias model is, however, a poor approximation to the data, especially on small scales (ℓ≤ 28 h −1 Mpc) where deterministic linear bias is excluded at high significance. A power-law bias model with index b 1 ≈ 0.75 is a significantly better fit to the data on all scales, although linear bias becomes consistent with the data for ℓ≳ 40 h −1 Mpc . 相似文献
867.
P. M. Phillips I. W. A. Browne P. N. Wilkinson 《Monthly notices of the Royal Astronomical Society》2001,321(2):187-198
We present the results of an unbiased radio search for gravitational lensing events with image separations between 15 and 60 arcsec, which would be associated with clusters of galaxies with masses >1013–14 M⊙ . A parent population of 1023 extended radio sources stronger than 35 mJy with stellar optical identifications was selected using the FIRST radio catalogue at 1.4 GHz and the APM optical catalogue. The FIRST catalogue was then searched for companions to the parent sources stronger than 7 mJy and with separation in the range 15 to 60 arcsec. Higher-resolution observations of the resulting 38 lens candidates were made with the VLA at 1.4 and 5 GHz, and with MERLIN at 5 GHz in order to test the lens hypothesis in each case. None of our targets was found to be a gravitational lens system. These results provide the best current constraint on the lensing rate for this angular scale, but improved calculations of lensing rates from realistic simulations of the clustering of matter on the relevant scales are required before cosmologically significant constraints can be derived from this null result. We now have an efficient, tested observational strategy with which it will be possible to make an order-of-magnitude larger unbiased search in the near future. 相似文献
868.
869.
M. A. Zwaan M. J. Meyer R. L. Webster L. Staveley-Smith M. J. Drinkwater D. G. Barnes R. Bhathal W. J. G. de Blok M. J. Disney R. D. Ekers K. C. Freeman D. A. Garcia B. K. Gibson J. Harnett P. A. Henning M. Howlett H. Jerjen M. J. Kesteven V. A. Kilborn P. M. Knezek B. S. Koribalski S. Mader M. Marquarding R. F. Minchin J. O'Brien T. Oosterloo M. J. Pierce R. M. Price M. E. Putman E. Ryan-Weber S. D. Ryder E. M. Sadler J. Stevens I. M. Stewart F. Stootman M. Waugh A. E. Wright 《Monthly notices of the Royal Astronomical Society》2004,350(4):1210-1219
870.