张同杰
零阶与高阶宇宙学: 标准宇宙学的理论和宇宙学的观测效应；引力理论与宇宙动力学；量子宇宙学；宇宙大尺度结构的形成和演化；宇宙微波背景辐射极其SZ效应；宇宙的黑暗时代与早期宇宙的再电离；宇宙中的引力透镜；宇宙学尺度上的高精度计算机数值模拟。
个性化签名
 姓名：张同杰
 目前身份：
 担任导师情况：
 学位：

学术头衔：
博士生导师， 教育部“新世纪优秀人才支持计划”入选者
 职称：

学科领域：
天体物理学
 研究兴趣：零阶与高阶宇宙学: 标准宇宙学的理论和宇宙学的观测效应；引力理论与宇宙动力学；量子宇宙学；宇宙大尺度结构的形成和演化；宇宙微波背景辐射极其SZ效应；宇宙的黑暗时代与早期宇宙的再电离；宇宙中的引力透镜；宇宙学尺度上的高精度计算机数值模拟。
1.教育背景及主要经历：
198688和199092年期间， 就读于山东省德州师专物理系和山东教育学院数学物理系。1993/09考入中国科学院上海天文台攻读硕士学位，1996/07获得天体物理硕士学位；1996/09在中国科学院上海天文台攻读博士学位，1999/07获得天体物理博士学位。1999/07进入北京师范大学天文系工作，2006/07晋升为北京师范大学教授至今，2007/07授予博士生导师至今。2003/09至今担任天体物理教研室主任。2000/08—2001/07期间, 在中国科学院北京天文台武向平宇宙学组 访问合作研究。2002/06—2002/07期间, 参加意大利国际理论物理中心(ICTP)天体粒子物理与宇宙学暑期讲习班。2002/06—2002/07期间, 在法国巴黎天体物理研究所(IAP) 访问并参加弱引力透镜会议。2002/05—2003/05期间, 在加拿大理论天体物理所(CITA)(多伦多大学) 访问合作研究。2005/06—2006/05, 在美国亚利桑那大学物理系和天文系(UofA)访问合作研究。2006/07参加第3届中意相对论天体物理研讨会（意大利Pescara）。2007/07参加第4届中意相对论天体物理研讨会（意大利Pescara）。2009/03—2012/03，兼职北京大学高能物理研究中心李政道学者。
2.研究方向：
零阶与高阶宇宙学: 标准宇宙学的理论和宇宙学的观测效应；引力理论与宇宙动力学；量子宇宙学；宇宙大尺度结构的形成和演化；宇宙微波背景辐射极其SZ效应；宇宙的黑暗时代与早期宇宙的再电离；宇宙中的引力透镜；宇宙学尺度上的高精度计算机数值模拟。
3.主讲课程：
(1)．天文系本科生： 《Theoretical Astrophysics》；(2)．天文系和物理系本科生：《Introduction to Cosmological Physics》（自编英文教材）；(3)．天文系和物理系硕博研究生：《Cosmological Physics 》 （自编英文教材）；(4). 全校文理本科生（公共选修课）：《Cosmology: The Creation, Evolution and End of the Universe》（中英文PPT）

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10
张同杰， TongJie Zhang a， b， Qiang Yuan c Tiang Lan a
，0001，（）：
1年11月30日
We employ an analytical approach to investigate the signatures of Baryon Acoustic Oscillations(BAOs) on the convergence power spectrum of weak lensing by large scale structure. It is shown that the BAOs wiggles can be found in both of the linear and nonlinear convergence power spectra of weak lensing at about 40≤1≤600, but they are weaker than that of matter power spectrum. Although the statistical error for LSST are greatly smaller than that of CFHT and SNAP survey especially at about 30<1<300, they are still larger than their maximum variations of BAOs wiggles. Thus, the detection of BAOs with the ongoing and upcoming surveys such as LSST, CFHT and SNAP survey confront a technical challenge.
cosmology: theory,， gravitational lensing,， largescale structure of universe

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张同杰， Qiang Yuan a， bHaoYi Wan a TongJie Zhang a， c， d， ∗JiRen Liu d LongLong Feng e， f LiZhi Fang d
，0001，（）：
1年11月30日
It has been revealed recently that, in the scale free range, i.e. from the scale of the onset of nonlinear evolution to the scale of dissipation, the velocity and mass density fields of cosmic baryon fluid are extremely well described by the selfsimilar logPoisson hierarchy. As a consequence of this evolution, the relations among various physical quantities of cosmic baryon fluid should be scale invariant, if the physical quantities are measured in cells on scales larger than the dissipation scale, regardless the baryon fluid is in virialized dark halo, or in previrialized state. We examine this property with the relation between the Compton parameter of the thermal SunyaevZel'dovich effect, y(r), and Xray luminosity, Lx(r), where r being the scale of regions in which y and Lx are measured. According to the selfsimilar hierarchical scenario of nonlinear evolution, one should expect that 1.) in the y(r)Lx(r) relation, y(r)=10A(r)[Lx(r)](r), the coefficients A(r) and (r) are scaleinvariant; 2.) The relation y(r)=10A(r)[Lx(r)] (r) given by cells containing collapsed objects is also available for cells without collapsed objects, only if r is larger than the dissipation scale. These two predictions are well established with a scale decomposition analysis of observed data, and a comparison of observed y(r)Lx(r) relation with hydrodynamic simulation samples. The implication of this result on the characteristic scales of nongravitational heating is also addressed.
cosmology: theory,， largescale structure of universe,， Xrays: galaxies: clusters,， hydrodynamics,， methods: numerical

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【期刊论文】Statefinder diagnostic for the modified polytropic Cardassian universe
张同杰， ZeLong Yi and TongJie Zhang∗
，0001，（）：
1年11月30日
We apply the statefinder diagnostic to the modified polytropic Cardassian universe in this work. We find that the statefinder diagnostic is quite effective to distinguish Cardassian models from a series of other cosmological models. The sr plane is used to classify the modified polytropic Cardassian models into six cases. The evolutionary trajectories in the sr plane for the cases with different and reveal different evolutionary properties of the universe. In addition, we combine the observational H(z) data, the cosmic microwave background data and the baryonic acoustic oscillation data to make a joint analysis. We find that Case 2 can be excluded at the 68.3% confidence level and any case is consistent with the observations at the 95.4% confidence level.

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【期刊论文】Constraints on the DGP Universe Using Observational Hubble parameter
张同杰， HaoYi Wan ， ZeLong Yi ， TongJie Zhang ， and Jie Zhou
，0001，（）：
1年11月30日
In this work, we use observations of the Hubble parameter from the differential ages of passively evolving galaxies and the recent detection of the Baryon Acoustic Oscillations (BAO) at z1=0.35 to constrain the DvaliGabadadzePorrati (DGP) universe. For the case with a curvature term, we set a prior h=0.73±0.03 and the bestfit values suggest a spatially closed Universe. For a flat Universe, we set h free and we get consistent results with other recent analyses.

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张同杰， ZeLong Yi， TongJie Zhang
，0001，（）：
1年11月30日
Using the absolute ages of passively evolving galaxies observed at different redshifts, one can obtain the differential ages, the derivative of redshift z with respect to the cosmic time t (i.e. dz/dt). Thus, the Hubble parameter H(z) can be measured through the relation H(z)=−(dz/dt)/(1 + z). By comparing the measured Hubble parameter at different redshifts with the theoretical one containing free cosmological parameters, one can constrain current cosmological models. In this paper, we use this method to present the constraint on a spatially flat FriedmannRobertWalker Universe with a matter component and a holographic dark energy component, in which the parameter c plays a significant role in this dark energy model. Firstly we consider three fixed values of c=0.6, 1.0 and 1.4 in the fitting of data. If we set c free, the best fitting values are c=0.26, m0=0.16, h=0.9998. It is shown that the holographic dark energy behaves like a quintomtype at the 1 level. This result is consistent with some other independent cosmological constrains, which imply that c<1.0 is favored. We also test the results derived from the differential ages using another independent method based on the lookback time to galaxy clusters and the age of the universe. It shows that our results are reliable.
Cosmology， cosmological parameters， holographic dark energy， the differential ages of galaxies

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张同杰， TongJie Zhang ， ， Jiren Liu ， Longlong Feng ， Ping He ， LiZhi Fang
，0001，（）：
1年11月30日
We study the Xray emission of baryon fluid in the universe using the WIGEON cosmological hydrodynamic simulations. It has been revealed that cosmic baryon fluid in the nonlinear regime behaves like Burgers turbulence, i.e. the fluid field consists of shocks. Like turbulence in incompressible fluid, the Burgers turbulence plays an important role in converting the kinetic energy of the fluid to thermal energy and heats the gas. We show that the simulation sample of the CDM model without adding extra heating sources can fit well the observed distributions of Xray luminosity versus temperature (Lx vs. T) of galaxy groups and is also consistent with the distributions of Xray luminosity versus velocity dispersion (Lx vs. σ). Because the baryonic gas is multiphase, the Lx−T and Lx−σ distributions are significantly scattered. If we describe the relationships by power laws Lx ∝ T LT and Lx ∝ σLV, we find αLT>2.5 and αLV>2.1. The Xray background in the soft 0.5−2 keV band emitted by the baryonic gas in the temperature range 105<T<107K has also been calculated. We show that of the total background, (1) no more than 2% comes from the region with temperature less than 106.5 K, and (2) no more than 7% is from the region of dark matter with mass density ρdm<50 ρdm. The region of ρdm>50 ρdm is generally clustered and discretely distributed. Therefore, almost all of the soft Xray background comes from clustered sources, and the contribution from truly diffuse gas is probably negligible. This point agrees with current Xray observations.
cosmology: theorylargescale structure of universeXrays: diffuse backgroundmethods: numerical

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张同杰， TongJie Zhang， UeLi Pen
，0001，（）：
1年11月30日
Weak lensing measurements are starting to provide statistical maps of the distribution of matter in the universe that are increasingly precise and complementary to cosmic microwave background maps. The probability distribution (PDF) provides a powerful tool to test nonGaussian features in the convergence field and to discriminate the different cosmological models. In this letter, we present a new PDF space Wiener filter approach to reconstruct the probability density function of the convergence from the noisy convergence field. We find that for parameters comparable to the CFHT legacy survey, the averaged PDF of the convergence in a 3 degree field can be reconstructed with an uncertainty of about 10%, even though the pointwise PDF is noise dominated.
cosmology: observationscosmology: theorydark mattergravitational lensinglargescale structure of universemethods: Nbody simulations

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【期刊论文】Gravitational Lensing by Dark Matter Halos with Nonuniversal
张同杰， Density Profiles， TongJie Zhang
，0001，（）：
1年11月30日
The statistics of gravitational lensing can provide us with a very powerful probe of the mass distribution of matter in the universe. By comparing predicted strong lensing probabilities with observations, we can test the mass distribution of dark matter halos, in particular, the inner density slope. In this letter, unlike previous work that directly models the density profiles of dark matter halos semianalytically, we generalize the density profiles of dark matter halos from highresolution Nbody simulations by means of generalized NavarroFrenkWhite (GNFW) models of three populations with slopes, α, of about 1.5, 1.3 and 1.1 for galaxies, groups and clusters, respectively. This approach is an alternative and independent way to examine the slopes of mass density profiles of halos. We present calculations of lensing probabilities using these GNFW profiles for three populations in various spatially flat cosmological models with a cosmological constant. It is shown that the compound model of density profiles does not match well with the observed lensing probabilities derived from the JodrellBank VLA Astrometric Survey data in combination with the Cosmic Lens AllSky Survey data. Together with the previous work on lensing probability, our results suggest that a singular isothermal sphere mass model of less than about 1013h−1M⊙ can predict strong lensing probabilities that are consistent with observations of small splitting angles.
cosmology:observationscosmology: theorygravitational lensingdark mattergalaxies:clusters: generalgalaxies: halos

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【期刊论文】Optimal Weak Lensing Skewness Measurements
张同杰， TongJie Zhang， UeLi Pen， Pengjie Zhang， John Dubinski
，0001，（）：
1年11月30日
Weak lensing measurements are starting to provide statistical maps of the distribution of matter in the universe that are increasingly precise and complementary to cosmic microwave background maps. The most common measurement is the correlation in alignments of background galaxies which can be used to infer the variance of the projected surface density of matter. This measurement of the fluctuations is insensitive to the total mass content and is analogous to using waves on the ocean to measure its depths. However, when the depth is shallow as happens near a beach waves become skewed. Similarly, a measurement of skewness in the projected matter distribution directly measures the total matter content of the universe. While skewness has already been convincingly detected, its constraint on cosmology is still weak. We address optimal analyses for the CFHT Legacy Survey in the presence of noise. We show that a compensated Gaussian filter with a width of 2.5 arc minutes optimizes the cosmological constraint, yielding m/m 10%. This is significantly better than other filters which have been considered in the literature. This can be further improved with tomography and other sophisticated analyses.
Cosmologytheorysimulationobservation: gravitational lensing,， dark matter,， large scale structure,， window function

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【期刊论文】Detection of dark matter Skewness in the VIRMOSDESCART survey: Implications for Ω0
张同杰， UeLi Pen， Tongjie Zhang， Ludovic van Waerbeke， Yannick Mellier， Pengjie Zhang， John Dubinski
，0001，（）：
1年11月30日
Weak gravitational lensing provides a direct statistical measure of the dark matter distribution. The variance is easiest to measure, which constrains the degenerate product 8 0.6 0. The degeneracy is broken by measuring the skewness arising from the fact that densities must remain positive, which is not possible when the initially symmetric perturbations become nonlinear. Skewness measures the nonlinear mass scale, which in combination with the variance measures 0 directly. We present the first detection of dark matter skewness from the VirmosDecart survey. We have measured the full three point function, and its projections onto windowed skewness. We separate the lensing mode and the B mode. The lensing skewness is detected for a compensated Gaussian on scales of 5.37 arc minutes to be k3=1.06±0.06×10−6. The Bmodes are consistent with zero at this scale. The variance for the same window function is k2=5.32±0.62±0.98×10−5, resulting in S3=375+342−124. Comparing to Nbody simulations, we find 0<0.5 at 90% confidence. The CanadaFranceHawaiiTelescope legacy survey and newer simulations should be able to improve significantly on the constraint.
Cosmologytheorysimulationobservation: gravitational lensing,， dark matter,， large scale structure

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