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Hill’s equations are an approximation that is useful in a number of areas of astrophysics including planetary rings and planetesimal disks. We derive a symplectic method for integrating Hill’sequation...
Curvature perturbation from velocity modulation
Curvature perturbation velocity modulation
2011/10/9
We propose a new variant model of the modulated reheating. If particles have large scale fluctuations on their velocities, or equivalently their Lorentz factors, the decay rate also fluctuates and the...
The charged dust solution of Ruban -- matching to Reissner--Nordström and shell crossings
shell crossings even half cycle oscillation minimal size
2011/10/14
The maximally extended Reissner--Nordstr\"om (RN) manifold with $e^2 < m^2$ begs for attaching a material source to it that would preserve the infinite chain of asymptotically flat regions and evolve ...
Fine-Tuning Implications of Direct Dark Matter Searches in the MSSM
Fine-Tuning Implications Direct Dark Matter Searches
2011/10/14
We study theoretical implications of direct dark matter searches in the minimal supersymmetric standard model (MSSM). We assume that no accidental cancellations occur in the spin-independent elastic n...
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. IV. Two bulge populations
Gravitational lensing: micro—Galaxy: bulge —Galaxy: formation —Galaxy: evolution —Stars: abundances
2011/10/20
Based on high-resolution (R~42000 to 48000) and high signal-to-noise (S/N~50 to 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn...
The small community of the Tomaraho, an ethnic group culturally derived from the Zamucos, became known in the South American and world anthropological scenario in recent times. This group, far from th...
Hubble's law and faster than light expansion speeds
Hubble's law faster than light expansion speeds
2011/10/14
Naively applying Hubble's law to a sufficiently distant object gives a receding velocity larger than the speed of light. By discussing a very similar situation in special relativity, we argue that Hub...
Time-Frequency Analysis of Superorbital Modulation of X-ray Binary SMC X-1 by Hilbert-Huang Transform
Time-Frequency Analysis Superorbital Modulation X-ray Binary SMC X-1 Hilbert-Huang Transform
2011/10/21
The high-mass X-ray binary (HMXB) SMC X-1 exhibits a superorbital modulation with a dramatically varying period ranging between ~40 d and ~60 d. This research studies the time-frequency properties of ...
TESELA: a new Virtual Observatory tool to determine blank fields for astronomical observations
Observatory determine blank fields astronomical observations
2011/10/12
The observation of blank fields, regions of the sky devoid of stars down to a given threshold magnitude, constitutes one of the typical important calibration procedures required for the proper reducti...
俄罗斯成功发射天体物理观测卫星
俄罗斯 发射 天体物理 观测卫星
2011/7/20
俄罗斯航天部门于莫斯科时间7月18日6时31分（北京时间当日10时31分）在哈萨克斯坦境内的拜科努尔发射场成功将“波谱-R”天体物理观测卫星发射升空。借助该卫星，研究人员可以获取银河系内外天体的高精度图像。
Gas and dust in a submillimeter galaxy at z = 4.24 from the Herschel ATLAS
submillimeter galaxy Herschel ATLAS
2011/10/9
We report ground-based follow-up observations of the exceptional source, ID141, one the brightest sources detected so far in the H-ATLAS cosmological survey. ID141 was observed using the IRAM 30-meter...
Can axion-like particles explain the alignments of the polarisations of light from quasars?
axion-like particles explain alignments polarisations
2011/9/30
The standard axion-like particle explanation of the observed large-scale coherent orientations of quasar polarisation vectors is ruled out by the recent measurements of vanishing of circular polarisat...
Variability of the SiO thermal line emission toward the young L1448-mm outflow
Variability SiO emission L1448-mm outflow
2011/10/8
The detection of narrow SiO thermal emission toward young outflows has been proposed to be a signature of the magnetic precursor of C-shocks. Recent modeling of the SiO emission across C-shocks predic...
Stochastic Acceleration and the Evolution of Spectral Distributions in SSC Sources: A Self Consistent Modeling of Blazars' Flares
Stochastic Acceleration Evolution Spectral Distributions
2011/9/30
The broad-band spectral distributions of non-thermal sources, such as those of several known blazars, are well described by a log-parabolic fit. The second degree term in these fits measures the curva...
Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei
Grating Observations Seyfert Galaxies Comparison
2011/9/26
We present a study of the core of the Fe Ka emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra High Energy Grating (HEG). The sample consists of 29 observations ...