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Formes d’asteroides et formation de satellites:role de la reaccumulation gravitationnelle
Solar System Asteroids Satellites Collisions
2015/12/25
Asteroid shapes and satellite formation: role of gravitational re-accumulation.Following current evidence, it is widely accepted that many asteroids would be ‘gravitational aggregates’, i.e. bodies la...
2012年6月6日，美国天文学会（the American Astronomical Society，AAS）出版董事会和理事会正式宣布聘请北京大学科维理天文与天体物理研究所何锐思教授担任《天体物理期刊通讯》（the Astrophysical Journal Letters）副主编，任期将从2013年1月1日开始，聘期五年。
Stability Constraints on Classical de Sitter Vacua
Stability Constraints Classical Sitter Vacua
2011/10/17
We present further no-go theorems for classical de Sitter vacua in Type II string theory, i.e., de Sitter constructions that do not invoke non-perturbative effects or explicit supersymmetry breaking l...
Nuclear de-excitation line spectrum of Cassiopeia A
Astroparticle physics – cosmic rays – ISM: supernova remnants
2011/10/13
The supernova remnant Cassiopeia A is a prime candidate for accelerating cosmic ray protons and ions. Gamma rays have been observed at GeV and TeV energies, which indicates hadronic interactions, but ...
Real-time, fast radio transient searches with GPU de-dispersion
Real-time fast radio transient searches de-dispersion
2011/10/8
The identification, and subsequent discovery, of fast radio transients through blind-search surveys requires a large amount of processing power, in worst cases scaling as $\mathcal{O}(N^3)$. For this ...
A sufficient condition for de Sitter vacua in type IIB string theory
moduli stabilization string vacua ux compacti cations
2011/10/18
We derive a sufficient condition for realizing meta-stable de Sitter vacua with small positive cosmological constant within type IIB string theory flux compactifications with spontaneously broken supe...
We study the motion of spinning test bodies in the de Sitter spacetime of constant positive curvature. With the help of the 10 Killing vectors, we derive the 4-momentum and the tensor of spin explici...
Influence of nuclear de-excitation on observables relevant for space exploration
nuclear de-excitation observables relevant
2011/1/13
The composition of the space radiation environment inside spacecrafts is modified by the interaction with shielding material, with equipment and even with the astronauts' bodies. Accurate quantitativ...
The mass-loss rates of red supergiants and the de Jager prescription
The mass-loss rates of red supergiants the de Jager prescription
2011/1/11
Mass loss of red supergiants (RSG) is important for the evolution of massive stars, but is not fully explained. Several empirical prescriptions have been proposed, trying to express the mass-loss rate...
We apply the nonstandard loop quantum cosmology method to quan-tize a flat FRW cosmological model with a free scalar field and the cosmological constant Λ > 0. Modification of the Hamiltonian in terms...
Pulsar timing arrays as imaging gravitational wave telescopes: angular resolution and source (de)confusion
Pulsar timing arrays imaging gravitational wave telescopes
2011/1/10
Pulsar timing arrays (PTAs) will be sensitive to a finite number of gravitational wave (GW) "point" sources (e.g. supermassive black hole binaries). N quiet pulsars with accurately known distances d_{...
Krein Spaces in de Sitter Quantum Theories
de Sitter group undecomposable representations Krein spaces Gupta–Bleuler triplet cohomology of representations
2010/3/19
Experimental evidences and theoretical motivations lead to consider the curved space-time relativity based on the de Sitter group $SO_0(1,4)$ or $Sp(2,2)$ as an appealing substitute to the flat space-...
在Tortoise坐标系中，利用brick wall模型研究了电磁场对Vaidya Bonner de Sitter黑洞熵的量子修正. 当黑洞事件视界不随超前时间变化时，结果与Reissner Nordstrom de Sitter黑洞的量子熵完全相同.
广义测不准关系与Reissner Nordstrom de Sitter黑洞熵
Reissner Nordstrom de Sitter黑洞 视界 熵 测不准关系 薄层brick wall方法
2009/10/21
针对Reissner Nordstrom de Sitter时空背景，利用经广义测不准关系改进的薄层brick wall方法计算了黑洞熵。结果表明，由这种方法得到的黑洞熵上限与它的外视界和宇宙视界面积之和成正比，和人们预期的结果相符。从中揭示了黑洞 熵与视界面积之间的内在联系，也进一步表明了黑洞熵是视界面上量子态的熵，是一种量子效应。由广义测不准关系的引入看到，brick wall方法与引力场量子...
El Observatorio de San Pedro Mártir：A World-Class Site for Large Telescopes
San Pedro Mártir Large Telescopes World-Class Site
2009/7/1
El Observatorio de San Pedro Mártir：A World-Class Site for Large Telescopes。