Showing papers in "Chinese Astronomy and Astrophysics in 2009"

TL;DR: In this article, a radio two-way time comparison between satellite and station, deduced in detail the reduction model of up-and downlink pseudo ranges between the satellite and the station, and provided a practical calculation model of clock error.

TL;DR: The general relation between the different types of satellite clock errors and the model exponential coefficients is summarized and compared with the IGS final clock error ephemeris product to test and verify the feasibility and availability of the improved prediction model proposed in the present article.

TL;DR: In this article, the authors presented a set of self-consistent data and energy spectrum formulae of near-earth space particles for the convenience of applications, by the simulative calculations with the software Geant 4, the background of HXMT and its variations with the time and orbit.

TL;DR: In this article, the authors used the 13.7m millimeter-wave telescope at the Qinghai Station of PMO to investigate the distribution of the CO molecular gas around SN 1572 and provide some observational basis for studying the relationship of SN1572 with its ambient molecular gas and the evolution of this SNR.

TL;DR: In this article, a simplified spherically symmetric atmospheric model is adopted to calculate the delay caused by the path bending, for different zenith distances, and the path of propagation path becomes a curve with an increased path-length so increasing the propagation time.

TL;DR: In this paper, a postprocessing method based on frame selection and multi-frame blind deconvolution is proposed for the restoration of high-resolution adaptive optics images, which can effectively compensate for the residual errors of the adaptive optics system on the image, and the restored image can reach the diffraction limited quality.

TL;DR: In this article, the authors adopted the method of deriving the cutoff proposed by Gan et al. and made a statistical analysis on 100 flares observed by the satellite Ramaty High Energy Solar Spectroscopy Imager (RHESSI) in 2002-2005.

TL;DR: In this paper, the authors used the Monte Carlo method to make numerical simulation of the dynamical evolution of embedded clusters and the result is compared with the observations, and they found that, due to the random motions of massive stars, temporary mass segregation may exist at certain times in the course of evolution of a given embedded cluster, and this phenomenon may be very prominent in some of them.

TL;DR: Based on the DWT (discrete wavelet transform) method, a new smoothing algorithm for computing surface densities from 3D numerical simulation samples was proposed in this paper, which can reconstruct accurately the surface density distribution of the gravitational lens simulation sample.

TL;DR: In addition to the atmosphere, the oceans play important roles in the excitation of the Chandler wobble as mentioned in this paper, and the contributions made by the Pacific Ocean, the Indian Ocean and the Atlantic Ocean from 1980 to 2005 to the excitations of the CHW are first and systematically researched by taking advantage of the data of the current velocity field and ocean floor pressure provided by the marine circulation model of the Estimating the Circulation and Climate of the Ocean (ECCO).

TL;DR: In this article, the lengths of three radii a, b and c of the ellipsoid and the Moon's figure in tidal equilibrium were calculated by using the lunar libration parameters and the sphericalharmonic gravity coefficients.

TL;DR: In this paper, the orbital period variations of the Algol-type semidetached binary UW Vir are analyzed based on the basic physical parameters given by Brancewicz and Dworak in 1980.

TL;DR: In this paper, a detailed analysis of the correlation between photon-count rate and spectral hardness ratio HR2 of the black-hole candidate X-ray binary Cyg X-1 in three energy bands, namely the A-band (1.5-3), B-band(3-5), and Cband (5-12-keV), was made.

TL;DR: Based on the Lambert equation and knowledge of space geometry, a method of orbit determination using the sparse observational data provided by the space monitoring electronic fence device is given in this paper, where the initial orbit determined by this method can be improved and can converge to a final accuracy better than 100m.

TL;DR: In this article, the authors used the 2003 interplanetary ephemeris frame of the PMOE to simulate the laser ranging between the ground-based station and the asteroid for 800 days from 2015 September 25 on and obtain the indeterminacies of 18 parameters, among which those of γ, β, J2 and Ġ/G are respectively 7.8, 10−8, 9.0, 10 −7, 9, 8, 8.8−10−11 and 7.0, 10−15yr−1, with each being 1 to 3 orders

TL;DR: In this paper, the influence of viscosity on the truncation radius of the accretion disks around the black holes for black hole X-ray binaries and low luminosity AGNs, as well as the changes between the high and low state in black hole x-ray binary and NGC 4636 AGN were studied.

TL;DR: In this paper, a new idea for determining atmospheric refraction by utilizing the differential method is proposed, which does not depend upon the strict local parameters and complex precise observational instrumentation, and the observational principle is relatively simple.

TL;DR: In this article, the authors studied the nonadiabatic oscillations of low and intermediate-degree (l = 1 − 25) g4-p39 modes for the Sun.

TL;DR: In this article, three versions of GPS ephemerides (igs, igr, and igu) are used to carry out orbit determination under the same conditions and to estimate the effect of the GPS accuracy on the accuracy of low earth orbit satellites.

TL;DR: In this article, the effect of the selection of sampling points on the result of spectral extraction is analyzed, and an improved extraction method based on the frequency-domain filtering is proposed.

TL;DR: In this paper, the authors used the initial mass function (IMF) of stars to explain the observed number distribution of the LGRBs with the redshift, and this has led to some good results.

TL;DR: In this article, simultaneous mapping observations at the 12CO, 13CO, and C18O lines were performed towards the 24 Galactic high-mass star-forming cores, which are associated with water masers and have available Spitzer's infrared data.

TL;DR: In this article, a novel pulse profile accumulation method based on the wavelet-modulus-maxima information is proposed, where the original observed data are divided into groups according to the pulse periods.

TL;DR: Based on the single-fluid MHD model of Mars space simulation, Wang et al. as discussed by the authors studied the magnetic field structure in the near-Mars space and investigated the influence of Martian crustal magnetic anomalies on the magnetic fields structure.

TL;DR: In this article, the authors made the double-band full-polarization observations towards the compact steep-spectrum source 1150+497, and obtained the distributions of the polarization flux intensity and polarization vector of this source at the 5 GHz and 8 GHz wave bands.

TL;DR: Based on relativistic kinematics, a relation between the photon number of the emission from the rapidly moving shock layer and the number of photons received by an observer is derived as mentioned in this paper.

TL;DR: In this paper, a wavelet analysis method for identifying the light period of the BL Lac object S5 0716+714 is introduced, which is consistent with the 3.3-year period given by Raiteri et al.

TL;DR: In this article, a tsunami model of the origin of multi-ring basins is discussed and an approximate formula for calculating the ring radius is obtained based on the theory of shallow water waves with an initial surface deformation of a parabolic crater.

TL;DR: In this article, the influence of the shock thickness and the second-order Fermi effect on the particle acceleration by diffusive shock waves is numerically studied through solving one-dimensional diffusive equation.

TL;DR: Using the N-body dynamical model that includes the sun, the 8 planets, Pluto, UB313 and massless particles, the authors simulate the orbital evolution of 551 Kuiper Belt Objects (KBOs) with known parameters.