On a repelling force between particles in a bath of thermal radiation     

A. Dinculescu 《Astrophysics and Space Science》2007,310(3-4):281-284

In an optically thin medium two particles in a bath of thermal radiation repel each other with a force directly proportional to the product of their cross sections and inversely proportional to the square of the distance between them. This force, which is mediated by the scattered photons, was in the past much larger than the gravitational attraction between scattering particles, and could have played a role in the formation of the first gravitationally bound systems.  相似文献   

9C: a survey of radio sources at 15 GHz with the Ryle Telescope   总被引：1，自引：0，他引：1  

Elizabeth M. Waldram  Guy G. Pooley  Keith J. B. Grainge  Michael E. Jones  Richard D. E. Saunders  Paul F. Scott  Angela C. Taylor 《Monthly notices of the Royal Astronomical Society》2003,342(3):915-925

The fields chosen for the first observations of the cosmic microwave background with the Very Small Array have been surveyed with the Ryle Telescope at 15 GHz. We have covered three regions around RA  00^h 20^m Dec. +30°  , RA  09^h 40^m Dec. +32°  and RA  15^h 40^m Dec. +43° (J2000.0)  , an area of  520 deg²  . There are 465 sources above the current completeness limit of  ≈25 mJy  , although a total of  ≈760  sources have been detected, some as faint as 10 mJy. This paper describes our techniques for observation and data analysis; it also includes source counts and some discussion of spectra and variability. Preliminary source lists are presented.  相似文献   

Is the present expansion of the Universe really accelerating?     

R. G. Vishwakarma 《Monthly notices of the Royal Astronomical Society》2003,345(2):545-551

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The Sunyaev–Zeldovich background     

Gilbert P. Holder †  Ian G. McCarthy  A. Babul 《Monthly notices of the Royal Astronomical Society》2007,382(4):1697-1706

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A measurement of H₀ from Ryle Telescope, ASCA and ROSAT observations of Abell 773     

Richard Saunders  Rüdiger Kneissl  Keith Grainge  William F. Grainger  Michael E. Jones  Alessia Maggi  Rhiju Das  †  Alastair C. Edge  Anthony N. Lasenby  G. G. Pooley  Shigeru J. Miyoshi  Taisuke Tsuruta  Koujun Yamashita  Yuzuru Tawara  Akihiro Furuzawa  Akihiro Harada  Izamu Hatsukade 《Monthly notices of the Royal Astronomical Society》2003,341(3):937-940

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On the presence of thermal Sunyaev–Zel'dovich induced signal in the first-year WMAP temperature maps     

C. Hernández-Monteagudo  J. A. Rubiño-Martín 《Monthly notices of the Royal Astronomical Society》2004,347(2):403-410

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A maximum-likelihood approach to removing radio sources from observations of the Sunyaev–Zel'dovich effect, with application to Abell 611     

William F. Grainger  Rhiju Das†  Keith Grainge  Michael E. Jones  Rüdiger Kneissl  G. G. Pooley  Richard D. E. Saunders 《Monthly notices of the Royal Astronomical Society》2002,337(4):1207-1214

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Astrophysical component separation of COBE-DMR 4-yr data with FastICA     

D. Maino  A. J. Banday  C. Baccigalupi  F. Perrotta  K. M. Górski 《Monthly notices of the Royal Astronomical Society》2003,344(2):544-552

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An improved approach to measuring H₀ using X-ray and SZ observations of galaxy clusters     

R. W. Schmidt  S. W. Allen  A. C. Fabian 《Monthly notices of the Royal Astronomical Society》2004,352(4):1413-1420

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Active microwave remote sensing for soil moisture measurement: a field evaluation using ERS‐2     

Jeffrey P. Walker  Paul R. Houser  Garry R. Willgoose 《水文研究》2004,18(11):1975-1997

Active microwave remote sensing observations of backscattering, such as C‐band vertically polarized synthetic aperture radar (SAR) observations from the second European remote sensing (ERS‐2) satellite, have the potential to measure moisture content in a near‐surface layer of soil. However, SAR backscattering observations are highly dependent on topography, soil texture, surface roughness and soil moisture, meaning that soil moisture inversion from single frequency and polarization SAR observations is difficult. In this paper, the potential for measuring near‐surface soil moisture with the ERS‐2 satellite is explored by comparing model estimates of backscattering with ERS‐2 SAR observations. This comparison was made for two ERS‐2 overpasses coincident with near‐surface soil moisture measurements in a 6 ha catchment using 15‐cm time domain reflectometry probes on a 20 m grid. In addition, 1‐cm soil moisture data were obtained from a calibrated soil moisture model. Using state‐of‐the‐art theoretical, semi‐empirical and empirical backscattering models, it was found that using measured soil moisture and roughness data there were root mean square (RMS) errors from 3·5 to 8·5 dB and r² values from 0·00 to 0·25, depending on the backscattering model and degree of filtering. Using model soil moisture in place of measured soil moisture reduced RMS errors slightly (0·5 to 2 dB) but did not improve r² values. Likewise, using the first day of ERS‐2 backscattering and soil moisture data to solve for RMS surface roughness reduced RMS errors in backscattering for the second day to between 0·9 and 2·8 dB, but did not improve r² values. Moreover, RMS differences were as large as 3·7 dB and r² values as low as 0·53 between the various backscattering models, even when using the same data as input. These results suggest that more research is required to improve the agreement between backscattering models, and that ERS‐2 SAR data may be useful for estimating fields‐scale average soil moisture but not variations at the hillslope scale. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献