搜索结果: 106-120 共查到“知识库 天体物理学”相关记录2715条 . 查询时间(2.922 秒)
Discovery of the correspondence between intra-cluster radio emission and a high pressure region detected through the Sunyaev-Zel'dovich effect
galaxies: clusters: individual: RX J1347-1145 – radio continuum: galaxies – X-rays: galaxies: clusters – cosmic back- ground radiation
2011/10/18
We analyzed new 237 MHz and 614 MHz GMRT data of the most X-ray luminous galaxy cluster, RX J1347-1145. Our radio results are compared with the MUSTANG 90 GHz Sunyaev-Zel'dovich effect map and with re...
A seesaw mechanism in an extra-dimension, known as the split seesaw mechanism, provides a natural way to realize a splitting mass spectrum of right-handed neutrinos. It leads to one keV sterile neutri...
On the equilibrium of self-gravitating neutrons, protons and electrons in β-equilibrium
equilibrium self-gravitating neutrons protons electrons β-equilibrium
2011/10/9
We have recently proved the impossibility of imposing the condition of local charge neutrality in a self-gravitating system of degenerate neutrons, protons and electrons in $\beta$-equilibrium. The co...
Second-generation microlensing planet surveys: a realistic simulation
surveys – gravitational lensing: micro – methods: statistical – binaries: general – planetary systems – Galaxy: stellar content
2011/10/20
Microlensing surveys, which have discovered about a dozen extrasolar planets to date, have focused on the small minority of high-magnification lensing events, which have a high sensitivity to planet d...
Self force via $m$-mode regularization and 2+1D evolution: II. Scalar-field implementation on Kerr spacetime
regularization 2+1D evolution Scalar-field implementation Kerr spacetime
2011/10/18
This is the second in a series of papers aimed at developing a practical time-domain method for self-force calculations in Kerr spacetime. The key elements of the method are (i) removal of a singular ...
Kneelike structure in the spectrum of the heavy component of cosmic rays observed with KASCADE-Grande
ultra-high energy cosmic rays KASCADE-Grande composition extensive air shower
2011/10/20
We report the observation of a steepening in the cosmic ray energy spectrum of heavy primary particles at about $8 \times 10^{16}$ eV. This structure is also seen in the all-particle energy spectrum, ...
Inflationary non-Gaussianities in the most general second-order scalar-tensor theories
Inflationary non-Gaussianities in the most general second-order scalar-tensor theories
2011/10/14
For very general scalar-field theories in which the equations of motion are at second-order, we evaluate the three-point correlation function of primordial scalar perturbations generated during inflat...
Do Fermi-LAT observations really imply very large Lorentz factors in GRB outflows ?
gamma-ray burst: general gamma-ray burst: individual: GRB 080916C radiative transfer radiation mechanisms: non-thermal
2011/10/20
Recent detections of GeV photons in a few GRBs by Fermi-LAT imply huge bulk Lorentz factors to avoid a large gamma gamma optical depth at high energy. Estimates can be as high as Gamma ~ 1000 in the m...
A Toy Model for 3:2:1 Ratio of HFQPOs in XTE J1550-564
black hole accretion disc magnetic field X-ray Binaries:XTE J1550-564 quasi-periodic oscillations state transition
2011/9/26
Based on a toy model of coexistence of the Blandford-Znajek (BZ) and magnetic coupling (MC) processes with a non-axisymmetric magnetic field, we explain a puzzling 3:2:1 ratio of the high-frequency Qu...
当具有各向同性速度分布的相对论电子穿过稠密气体区，或者轰击稠密气体区的表面时，切仑科夫效应将会产生一种特殊的原子或离子发射线，称做切仑科夫线状发射。这一预言在光学波段已由实验室的实验所证实。本文中指出了切仑科夫线状辐射在类星体和赛弗特1星系的宽发射线研究中的重要性，利用此新机制有可能解决类星体研究中的一些重大且长期没有解决的疑惑。例如宽氢线之间存在的反常强度比，特别是反常lya/lyb强度比的问题...
强磁场中相对论电子系集体的共振逆康普顿散射谱
高能天体物理学辐射机制:非热 方法:解析 gamma射线:一般
2011/9/26
强磁场中相对论电子的共振逆康普顿散射(RICS)是产生伽玛射线的有效机制. 以前的工作曾论证, 伽玛暴的早期伽玛射线辐射可能主要由该机制产生.利用此辐射机制, 伽玛暴研究中的一些困惑有可能得到较好的解释, 例如, 观测统计给出的``Amati关系''的起源, 两段式(折断式)的幂律谱的形成, 特别是其中的``死线问题''的解决方案, 还有偏振的存在, 等等. 文章中将重点讨论折断幂律谱形成问题.基...
LIGO S5对残余引力波的限制
残余引力波 宇宙学 暴涨
2011/9/25
由于LIGO探测器已经达到了其设计灵敏度，其最新的S5数据可以用来实现对于残余引力波的限制。残余引力波产生于暴涨期间，其解析谱对初始条件极为敏感，而初始条件主要由指数 、跑动谱指数 和张量-标量比 来描述。利用LIGO S5的两台探测器数据的交叉关联，我们得到了对参数 的限制。其中一个主要结果，利用LIGO给定的一对探测器的交叉关联，我们计算出对于不同的参数 情况下的残余引力波的信噪比值。同时，还...
光在稀薄电离气体中传播时的红移效应
宇宙学 红移 软光子 电离气体
2011/9/25
广阔的宇宙空间并不是真正的真空。实际上不同区域存在有密度不同的极其稀薄的电离气体。光量子在这样的空间中传播时存在有一种‘软光子发射过程’。本文对这一‘软光子发射过程’进行讨论。由于这个软光子发射过程的存在，光量子在这样的空间中传播过程中要产生红移。计算这一红移的公式在文中也已导出。利用这个红移，许多已观测到而无法解释的天文现象可以很好地加以解释。
We observed the young pulsar J1357--6429 with the {\it Chandra} and {\it XMM-Newton} observatories. The pulsar spectrum fits well a combination of absorbed power-law model ($\Gamma=1.7\pm0.6$) and bla...
Addressing the spin question in gravitational-wave searches: Waveform templates for inspiralling compact binaries with nonprecessing spins
Addressing spin question gravitational-wave searches Waveform templates inspiralling
2011/10/18
This paper presents a post-Newtonian (PN) template family of gravitational waveforms from inspiralling compact binaries with non-precessing spins, where the spin effects are described by a single "red...