排序方式： 共有132条查询结果，搜索用时 15 毫秒
51.
Peter Thejll, Chris Flynn, Hans Gleisner and Andrew Mattingly explain how classic astronomical techniques, married to the latest technology, can be used to observe earthshine, and learn about Earth's climate, among many other things. 相似文献
52.
Nikhil Padmanabhan Tamás Budavári David J. Schlegel Terry Bridges Jonathan Brinkmann Russell Cannon rew J. Connolly Scott M. Croom István Csabai Michael Drinkwater Daniel J. Eisenstein Paul C. Hewett Jon Loveday Robert C. Nichol Kevin A. Pimbblet Roberto De Propris Donald P. Schneider Ryan Scranton Uro&#; Seljak Tom Shanks István Szapudi Alexander S. Szalay David Wake 《Monthly notices of the Royal Astronomical Society》2005,359(1):237-250
53.
54.
55.
Julien Lesgourgues rew R. Liddle 《Monthly notices of the Royal Astronomical Society》2001,327(4):1307-1312
We use a wide range of observations to constrain cosmological models possessing a significant asymmetry in the lepton sector, which offer perhaps the best chance of reconciling a critical-density Universe with current observations. The simplest case, with massless neutrinos, fails to fit many experimental data and does not lead to an acceptable model. If the neutrinos have mass of order 1 eV (which is favoured by some neutrino observations), then models can be implemented which prove a good fit to the microwave anisotropies and large-scale structure data. However, taking into account the latest microwave anisotropy results, especially those from BOOMERANG, we show that the model can no longer accommodate the observed baryon fraction in clusters. Together with the observed acceleration of the present Universe, this puts considerable pressure on such critical-density models. 相似文献
56.
Antonio C. da Silva Domingos Barbosa rew R. Liddle Peter A. Thomas 《Monthly notices of the Royal Astronomical Society》2001,326(1):155-163
We use hydrodynamical N -body simulations to study the kinetic Sunyaev–Zel'dovich effect. We construct sets of maps, one square degree in size, in three different cosmological models. We confirm earlier calculations that on the scales studied the kinetic effect is much smaller than the thermal (except close to the thermal null point), with an rms dispersion smaller by about a factor of 5 in the Rayleigh–Jeans region. We study the redshift dependence of the rms distortion and the pixel distribution at the present epoch. We compute the angular power spectra of the maps, including their redshift dependence, and compare them with the thermal Sunyaev–Zel'dovich effect and with the expected cosmic microwave background anisotropy spectrum as well as with determinations by other authors. We correlate the kinetic effect with the thermal effect both pixel-by-pixel and for identified thermal sources in the maps to assess the extent to which the kinetic effect is enhanced in locations of strong thermal signal. 相似文献
57.
Yiannis Tsapras Rachel A. Street Keith Horne Alan Penny Fraser Clarke Hans Deeg Francisco Garzon Simon Kemp Maria Rosa Zapatero Osorio Alejandro Oscoz Abad Santiago Madruga Sanchez Carlos Eiroa Alcione Mora Antxon Alberdi rew Cameron John K. Davies Roger Ferlet Carol Grady Allan W. Harris Javier Palacios reas Quirrenbach Heike Rauer Jean Schneider Dolf de Winter Bruno Merin Enrique Solano 《Monthly notices of the Royal Astronomical Society》2001,325(3):1205-1212
In 1998 the EXPORT team monitored microlensing event light curves using a charge-coupled device (CCD) camera on the IAC 0.8-m telescope on Tenerife to evaluate the prospect of using northern telescopes to find microlens anomalies that reveal planets orbiting the lens stars. The high airmass and more limited time available for observations of Galactic bulge sources make a northern site less favourable for microlensing planet searches. However, there are potentially a large number of northern 1-m class telescopes that could devote a few hours per night to monitor ongoing microlensing events. Our IAC observations indicate that accuracies sufficient to detect planets can be achieved despite the higher airmass. 相似文献
58.
59.
60.