检索结果-南通市图书馆

Systematic distortion in cosmic microwave background maps

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： lIU Hao 1,3 &lI TiPei 1,2.1key laboratory of {2. astrophysics,Institute of high energy physics,chinese academy of sciences,beijing 100049,China 2.enter for astrophysics,Tsinghua University,beijing 100084,China 3 Graduate University of chinese academy of sciences,beijing 100049,China key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Center for astrophysics Tsinghua University Beijing China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit lCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis

Narrow line Seyfert 1 galaxies: where are the broad line regions?

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2010年第12期53卷 2307-2311,2339-2343页

作者： MAO WeiMing 1,2.3 , HU Chen 2., WANG JianMin 2., BIAN WeiHao 4 , ZHANG Shu 2.& ZHAO Gang 1 1 key laboratory of Optical Astronomy, National Astronomical Observatories,{2., beijing 100012. China 2.key laboratory for particle astrophysics, Institute of high energy physics,{2.,{12., China 3 Graduate University of the{2.,{12., China 4 Department of physics, Nanjing Normal University, Nanjing 2.0011, China key laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing China key laboratory for {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of the chinese academy of sciences Beijing China Department of physics Nanjing Normal University Nanjing China

A sample consisting of 2.1 narrow line Seyfert 1 galaxies (NlS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the Hβ profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined Hβ reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

关键词： black hole physics galaxies: evolution quasars: general

New evidence for lack of CMB power on large scales

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： lIU Hao1 & lI TiPei1,2.3 1 key laboratory of {2. 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 {2. 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 digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

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

在线全文

学校读者我要写书评

暂无评论

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,{2. 100084,China 2.key laboratory of particle astrophysics,Institute of high energy physics,chinese academy of {12.,{2. 100049,China Department of physics & Center for astrophysics Tsinghua University Beijing China key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 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

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

在线全文

学校读者我要写书评

暂无评论

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,{2. 100084,China 2.key laboratory of particle astrophysics,Institute of high energy physics,chinese academy of {12.,{2. 100049,China Department of physics and Tsinghua Center for astrophysics Tsinghua University Beijing China key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 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 2.BlR/V 2.MlR,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.(2.05);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

Deprojection technique for galaxy cluster considering the point spread function

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2010年第S1期53卷 183-186页

作者： WANG YuSa,JIA ShuMei & CHEN Yong key laboratory for {2. astrophysics,Institute of high energy physics,chinese academy of sciences,beijing 100049,China key laboratory for {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China

We present a new method for the analysis of Abell 1835 observed by *** method is a combination of the Direct Demodulation technique and *** eliminate the effects of the point spread function(PSF) with the Direct Demodulation *** then use a traditional deprojection technique to study the properties of Abell *** to only using a deprojection method,the central electron density derived from this method increases by 30%,while the temperature profile is similar.

关键词： PSF Direct Demodulation deprojection Abell 1835 galaxy cluster XMM-Newton

Inconsistency between WMAP data and released map

在线全文

学校读者我要写书评

暂无评论

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 {2. 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 {2. 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

On the knee of Galactic cosmic rays in light of sub-TeV spectral hardenings

在线全文

学校读者我要写书评

暂无评论

chinese physics C 2018年第7期42卷 113-122页

作者： Yi-Qing Guo1 2.Qiang Yuan1 3 1. key laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory {2. academy of sciences Nanjing 2.0008 China 2. key laboratory of particle astrophysics Institute of high energy physics key laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of Sciences key laboratory of {2. astrophysics Institute of High Energy PhysicsChinese Academy of Sciences School of Astronomy and Space Science University of Science and Technology of China

More than fifty years after the discovery of the knee in the cosmic ray （CR） spectra, its physical origin remains a mystery. This is partly due to the ambiguity of the energy spectra of individual components. Recently, direct measurements from several space experiments found significant spectral hardenings of CR nuclei at ~2.0 GV. A joint modeling of the direct and indirect measurements may help to understand the experimental systematics and the physics of the knee. In this work, we update the phenomenological ＂poly-gonato＂ model to include the spectral hardenings, with a changing spectral index of γ ＋ β·logE. This modification gives a reasonable description of the CR spectra in a wide energy range. However, the fits to different data sets give different results. We find that the fit to the AMS-02.and CREAM data slightly favors a relatively low energy knee of the light components. In such a case, the expected all-particle spectra under-shoot the data, which may require an extra component of CRs. The fits to AMS-02.data and the light component （H＋He） data from the Tibet ASγ/ARGO-YBJ/WFCTA and KASCADE experiments give consistent results with the all-particle spectra. We further propose a possible physical realization of such a ＂modified poly-gonato＂ model of spectral hardenings by means of spatially-dependent diffusion of CRs. We find reasonably good agreement between the model predictions and the data for CR spectra, the secondary-to-primary ratios, and the amplitude of anisotropies.

关键词： cosmic ray knee spectrum propagation

Simulation of the in-flight calibration of the collimator alignment and PSF for HXMT

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2010年第S1期53卷 47-50页

作者： XIONG Shaolin,lI XinQiao,QU Jinlu & lU FangJun key laboratory for {2. astrophysics,Institute of high energy physics,chinese academy of sciences(CAS),beijing 100049,China key laboratory for {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences (CAS) Beijing China

The Hard X-ray Modulation Telescope(HXMT) is an X-ray astronomical satellite in 1-2.0 keV,consisting of three collimated *** present the in-flight calibration approach of the collimator alignment and Point Spread Function(PSF) for HXMT,using both the direct fitting method and the imaging *** to observational simulations of the Crab Nebula,we find that these two methods produce almost the same calibration accuracy of the alignment,and with a one-day scanning observation,the alignment can be calibrated to better than 0.45' and 0.1' along the wide and narrow directions of the Field of View(FOV) for a detector module,which corresponds to a localization accuracy of better than 0.1' and meets the scientific requirement.

关键词： HXMT alignment PSF calibration