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Constraints on Cardassian universe from Gamma ray bursts

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1720-1725页

作者： WANG TaiShan1 & LIANG Nan2 1 department of physics & center for astrophysics,tsinghua university,beijing 100084,china 2 department of Astronomy,beijing Normal university,beijing 100875,china 1. department of physics & center for astrophysics Tsinghua University Beijing 100084 China2. Department of Astronomy Beijing Normal University Beijing 100875 China

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the recently derived 42 gamma-ray bursts(GRBs) data calibrated with the method that can avoid the circularity *** results show that GRBs can be an optional observation to constrain the Cardassian *** the GRBs data with the newly de-rived size of baryonic acoustic oscillation peak from the Sloan Digital Sky Survey(SDSS),and the position of the first acoustic peak of the Cosmic Microwave Background radiation(CMB) from Wilkinson Microwave Anisotropy Probe(WMAP),we find Ωm0=0.27+0.02-0.02,n=0.06+0.07-0.08(1σ) for the original Cardassian model,and Ωm0=0.27+0.23-0.02,n=-0.09+0.23-1.91,β=0.82+2.10-0.62(1σ) for the modified polytropic Cardassian model.

关键词： Cardassian Gamma ray burst Cosmic Microwave Background baryonic acoustic oscillation

Inconsistency between WMAP data and released map

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Chinese Science Bulletin 2010年第10期55卷 907-909页

作者： LIU Hao1 & LI TiPei1,2,3 1 Key Laboratory of Particle astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china 2 department of physics & center for astrophysics,tsinghua university,beijing 100084,china 3 department of Engineering physics & center for astrophysics,tsinghua university,beijing 100084,china Key Laboratory of Particle astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China department of physics & center for astrophysics Tsinghua University Beijing China department of Engineering physics & center for astrophysics Tsinghua University Beijing China

A remarkable inconsistency between the calibrated differential time-ordered data (TOD) of the Wilkinson Microwave Anisotropy Probe (WMAP) mission,which is the input for map-making,and the cosmic microwave background (CMB) temperature maps published by the WMAP team is revealed,indicating that there must exist a serious problem in the map making routine of the WMAP *** inconsistency is easy to be confirmed without the use of WMAP map-making *** view of the importance of this issue for cosmology study,we invite readers to check it by themselves.

关键词：威尔金森微波各向异性探测器 WMAP 地图制作宇宙微波背景有序数据制作软件 TOD CMB

Diagnostics for the structure of AGNs'broad line regions with reverberation mapping data:confirmation of the two-component broad line region model

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 196-201页

作者： ZHU Ling1 & ZHANG ShuangNan2 1 department of physics and tsinghua center for astrophysics,tsinghua university,beijing 100084,china 2 Key Laboratory of Particle astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china 1. department of physics and tsinghua center for astrophysics Tsinghua University Beijing 100084 China 2. Key Laboratory of Particle astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

We re-examine the ten Reverberation Mapping(RM) sources with public data based on the two-component model of the Broad Line Region(BLR).In fitting their broad Hβ Mlines,six of them only need one Gaussian component,one of them has a double-peak profile,one has an irregular profile,and only two of them need two components,i.e.,a Very Broad Gaussian Component(VBGC) and an Inter-Mediate Gaussian Component(IMGC).The Gaussian components are assumed to come from two distinct regions in the two-component model;they are the Very Broad Line Region(VBLR) and the Inter-Mediate Line region(IMLR).The two sources with a two-component profile are Mrk 509 and NGC *** time lags of the two components of both sources satisfy tIMLR/tVBLR=V 2VBLR/V 2IMLR,where tIMLR and tVBLR are the lags of the two components while VIMLR and VVBLR represent the mean gas velocities of the two regions,supporting the two-component model of the BLR of Active Galactic Nuclei(AGNs).The fact that most of these ten sources only have the VBGC confirms the assumption that RM mainly measures the radius of the VBLR;consequently,the radius obtained from the R-L relationship mainly represents the radius of ***,NGC 4051,with a lag of about 5 days in the one component model,is an outlier on the R-L relationship as shown in Kaspi et al.(2005);however this problem disappears in our two-component model with lags of about 2 and 6 days for the VBGC and IMGC,respectively.

关键词： broad line region AGN Reverberation Mapping cross correlation

Bifurcation timescales in power spectra of black hole binaries and ultraluminous X-ray sources

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 177-182页

作者： WANG TaiShan1 & LI TiPei1,2 1 department of physics & center for astrophysics,tsinghua university,beijing 100084,china 2 Key Laboratory of Particle astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china tsinghua Univ Dept Phys Beijing 100084 Peoples R China tsinghua Univ Ctr Astrophys Beijing 100084 Peoples R China Chinese Acad Sci Inst High Energy Phys Key Lab Particle Astrophys Beijing 100049 Peoples R China

For black hole binaries(BHBs) and active galactic nuclei(AGNs),bifurcation timescales(BTs) Δtb exist,below which time-domain power is significantly higher than the corresponding Fourier ***-periodic oscillations(QPOs) are removed from the Fourier spectra of BHBs.A relationship between BT,black hole mass and bolometric luminosity is *** anti-correlation between BT and luminosity of Cyg X-1 is *** removing the QPOs,BTs are also obtained for two ultraluminous X-ray sources(ULXs),M82 X-1 and NGC5408 *** results support that they harbor intermediate mass black holes(IMBHs).

关键词： black hole binary ultraluminous X-ray source power spectral density data analysis

The correlation timescale of the X-ray flux during the outbursts of soft X-ray transients

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 161-167页

作者： WU YuXiang1,2,YU WenFei1 & LI TiPei2 1 Shanghai Astronomical Observatory,Shanghai 100012,china 2 department of Engineering physics & center for astrophysics,tsinghua university,beijing 100084,china Shanghai Astron Observ Shanghai 100012 Peoples R China tsinghua Univ Dept Engn Phys Beijing 100084 Peoples R China tsinghua Univ Ctr Astrophys Beijing 100084 Peoples R China

Recent studies of black hole and neutron star low mass X-ray binaries(LMXBs) show a positive correlation between the X-ray flux at which the low/hard(LH)-to-high/soft(HS) state transition occurs and the peak flux of the following HS *** analyzing the data from the All Sky Monitor(ASM) onboard the Rossi X-ray Timing Explorer(RXTE),we show that the HS state flux after the source reaches its HS flux peak still correlates with the transition flux during soft X-ray transient(SXT) *** studying large outbursts or flares of GX 339-4,Aql X-1 and 4U 1705-44,we have found that the correlation holds up to 250,40,and 50 d after the LH-to-HS state transition,*** time scales correspond to the viscous time scale in a standard accretion disk around a stellar mass black hole or a neutron star at a radius of-104-5 Rg,indicating that the mass accretion rates in the accretion flow either correlate over a large range of radii at a given time or correlate over a long period of time at a given *** the accretion geometry is a two-flow geometry composed of a sub-Keplerian inflow or outflow and a disk flow in the LH state,the disk flow with a radius up to-105 Rg would have contributed to the nearly instantaneous non-thermal radiation directly or indirectly,and therefore affects the time when the state transition occurs.

关键词： accretion disks black hole physics star:individual(Aquila X-1 GX 339-4 4U 1705-44)

Temporal study of GRS 1915+105 with rms-flux relation:The importance of magnetic activities in the corona

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 120-124页

作者： HAN Dong1,ZHANG ShuangNan2 & SONG LiMing2 1 department of Engineering physics & center for astrophysics,tsinghua university,beijing 100084,china 2 Key Laboratory of Particle astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china 1. department of Engineering physics & center for astrophysics Tsinghua University Beijing 100084 China 2. Key Laboratory of Particle astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

The rms-flux relations for some observations of GRS 1915+105 are *** rms-flux relations of the light curves in only one state,state C or state A,can be described by the simple non-linear model provided Zhang;we thus interpret that such a linear relation reflects the relative importance of magnetic instability for X-ray emission in the corona of the system,compared to the thermal viscous instability for the X-ray emission in the accretion *** rms-flux relations for state B are very scattered,possibly because of the dominance of thermal viscous instability for the X-ray emission in the accretion *** complex rms-flux relations for the observations of transitions between two or three states are caused by the combination of the different rms-flux relations of these *** underlying physical processes are the combination of magnetic topology in the corona and thermal viscous instability in the accretion disk.

关键词： rms-flux relation data analysis GRS 1915+105 magnetic instability

Hard X-ray lags of Cygnus X-1 on short timescales

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 150-152页

作者： JIN Jing1,LU Yu2,3,QU JinLu2 & LI TiPei1,2 1 department of Engineering physics & center for astrophysics,tsinghua university,beijing 100084,china 2 Key Laboratory of Particle astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china 3 Graduate university of Chinese Academy of Sciences,beijing 100049,china 1. department of Engineering physics & center for astrophysics Tsinghua University Beijing 100084 China2. Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Calculating the time lags over different timescales using the cross-correlation technique may lead to a biased estimate of small *** a timescale for lightcurve binning,we propose to subtract the local average instead of the global average during the cross-correlation,in order to filter variations on timescales larger than the bin *** new method allows us to make an unbiased estimate of the time lags using RXTE/PCA data on timescales as small as-5 ms,where the Fourier technique becomes *** calculate the time lag spectra of Cygnus X-1 at different spectral states with the new method,and find that the source appears to have similar X-ray lags on small timescales independent of its spectral states.

关键词： spectral lags Cygnus X-1 data analysis

Timing in the Time Domain: Cygnus X-1

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Chinese Journal of Astronomy and astrophysics 2001年第4期1卷 313-332页

作者： Ti-Pei Li (department of physics and center for astrophysics, tsinghua university, beijing 100084 High Energy astrophysics Lab., Institute of High Energy physics, Chinese Academy of Sciences, beijing 100039)E-mail:litp@*** department of physics and center for astrophysics Tsinghua University Beijing 100084 High Energy Astrophysics Lab. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039

Quantities characterizing temporal property, e.g., power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variability duration, and correlation between different characteristic quamtities on different time scale can be studied in the time domain as well. The temporal analysis technique in the time domain is a powerful tool, particularly in studying rapid variability on short time scales (or in high frequencies). Results of studying variabilities of X-rays from Cyg X-1 with the analysis technique in the time domain and RXTE data reveal valuable clues to understanding production and propagation processes of X-rays and structure of accretion disk in the black hole system.

关键词： methods: data analysis - stars: individual (Cygnus X-1) - X-rays: stars

Dense coding scheme using superpositions of Bell-states and its NMR implementation

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Science china(physics,Mechanics & Astronomy) 2005年第1期48卷 57-67页

作者： ZHANG Jingfu, XIE Jingyi, DENG Zhiwei & LU Zhiheng Key Laboratory for Quantum Information and Measurements, department of physics, tsinghua university, beijing 100084, china center for Quantum Information, tsinghua university, beijing 100084, china department of Materials Science and Engineering, beijing Normal university, beijing 100875, china Testing and Analytical center, beijing Normal university, beijing 100875, china department of physics, beijing Normal university, beijing 100875, china 1. Key Laboratory for Quantum Information and Measurements Department of Physics Tsinghua University 100084 Beijing China 2. center for Quantum Information Tsinghua University 100084 Beijing China 3. department of Materials Science and Engineering Beijing Normal University 100875 Beijing China 4. Testing and Analytical center Beijing Normal University 100875 Beijing China 5. department of physics Beijing Normal University 100875 Beijing China

Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR)quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system.

关键词： dense coding, superpositions of Bell-states, generalized Grover's algorithm, nuclear magnetic res-onance, quantum computer.