Review of High Energy Astrophysics Research in Mainland China

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Review of High Energy Astrophysics Research in
Mainland China
Zhang, Shuang Nan
Tsinghua Center for Astrophysics (THCA) and
Physics Department Tsinghua University, Beijing,
China
Key Lab for Particle Astrophysics Institute of
High Energy Physics Chinese Academy of Sciences
National Space Science Technology Center
(NSSTC) and Physics Department University of
Alabama in Huntsville, AL, USA
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Institutions involved in high energy astrophysics
(I)

• Beijing
• Institute of High Energy Physics, Chinese Academy
  of Sciences
• Tsinghua University
• Peking University
• National Astronomical Observatories, Chinese
  Academy of Sciences
• Beijing Normal University
• Nanjing
• Nanjing University
• Nanjing Purple Mountain Observatory, Chinese
  Academy of Sciences
• Shanghai
• Shanghai Observatory, Chinese Academy of Sciences
• Shanghai Jiao-Tong University

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Institutions involved in high energy astrophysics
(II)

• Hefei University of Science and Technology of
  China, Chinese Academy of Sciences
• Kunming
• Yunnan University
• Yunnan Observatory, Chinese Academy of Sciences
• Guangzhou Guangzhou University
• Wuhan
• Central China Normal University
• Central China University of Science and
  Technology
• Urumqi Radio Astronomy Station
• Xiamen Xiamen University

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Urumqi
Kunming
Guangzhou
Wuhan
Beijing
Hefei
Shanghai
Nanjing
Xiamen
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Urumqi
Kunming
Guangzhou
Wuhan
Beijing
Hefei
Shanghai
Nanjing
Xiamen
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High energy astrophysics research in Beijing

• Institute of High Energy Physics, Chinese Academy
  of Sciences
• Tsinghua University
• Peking University
• National Astronomical Observatories, Chinese
  Academy of Sciences
• AGN, clusters of galaxies, gamma-ray bursts,
  pulsars, accretion disks
• Beijing Normal University
• Accretion disks, X-ray binaries

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Institute of High Energy Physics, CAS

• Key Lab and Center for Particle Astrophysics
• Ground-based high energy gamma-ray astronomy
• Tibet AS-gamma experiment
• Tibet ARGO-YBJ array
• Space-borne high energy astrophysics
• Instrumentation
• Hard X-ray Modulation Telescope (future satellite
  mission)
• Gamma-ray burst monitor aboard the Shen-Zhou-II
  space lab.
• Balloon-borne hard X-ray telescope
• Small satellite RD
• Observations and data analysis
• black hole and X-ray binaries, AGNs, gamma-ray
  bursts, supernova remnants, pulsars
• Theoretical astrophysics
• Accretion disks, gamma-ray bursts

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YBJ International Cosmic Ray Observatory
Tibet -Lhasa 4300 m asl China-Japan AS-?
China-Italy ARGO Cosmic-ray High Energy
Gamma-ray
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ARGO-YBJ

• China-Italy
• _at_4300 m above sea level, 606 g/cm2
• 71x74 m2 full coverage of single layer RPC
  (resistive Plate Counters)
• 100x100 m2 partial (50) coverage
• 0.5 cm lead converter
• gamma-ray threshold 100 GeV
• field of view -100 to 700
• sensitivity 0.1 Crab _at_ 100 GeV
• 2.5 sigma detection of 30 flux variation of Crab
  within 20 days
• status
• detectors and electronics being assembled
• partial data taking in late 2002 or early 2003

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Morphology
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Model Close Cousin to the Crab Nebula
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Doppler boosting model for the ring
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Tsinghua University Hard X-ray Modulation
Telescope

• 1000 kg satellite mission
• Survey of stellar mass and supermassive black
  holes
• Broad band (15 - 200 keV) and high precision
  X-ray timing studies
• Current 973 project Phase-A (40 million CNY
  5M)
• full mission cost 100M
• Main participating institutions
• CAS Institute of High Energy Physics and Center
  for Space Science and Application Research
• Tsinghua University Astrophysics Center, Physics
  Department, Engineering Physics Department, Space
  Center
• Possible international collaborations
• Institute of TeSRE/CNR (Italy) to provide
  focusing X-ray optics and wide-field X-ray camera
• Tubingen University (Germany) to provide
  electronics, data acquisition
• University of Southampton (UK) mission
  optimization, space environments

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Tsinghua University Multiwavelength Small
Satellite Mission

• 100 kg satellite mission wide field X-ray
  telescope optical telescopes gamma-ray
  monitor
• Formation of black holes gamma-ray bursts and
  supernovae
• Evolution of black holes broad band (0.5 - 30
  keV) high precision spectral study (150-300 eV)
• Being proposed by Tsinghua, Nanjing University,
  National Astronomical Observatoroies and
  Institute of High Energy Physics (CAS)
• Full mission cost 8M
• Satellite to be build by Tsinghua Space Center
• Possible international collaborations
• U.K., Italy, Germany, H.K.

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Tsinghua University Theoretical Astrophysics

• Compact objects
• Neutron stars pulsars and pulsar wind
• Strange stars state of equation, surface
  properties
• Black holes formation and evolution
• Gamma-ray bursts origin and properties
• Magnetohydrodynamics
• Solar g-modes
• MHD density waves and tidal waves
• Quasi-periodic burst activities of Jupiter
• Circumnuclear starburst rings
• Accretion disks and outflows
• Global disk solutions
• Non-thermal particle energy distributions
• General relativistic effects and high-energy
  particle interactions

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Tsinghua University Observational
Astrophysics

• Direct Demodulation technique for non-focusing
  imaging
• The Hard X-ray Modulation Telescope
• New timing analysis technique in the time domain
• Power density, Variability,Time-lag
• Sometimes more advantageous than FFT based timing
  analysis methods
• New spectral-correlation technique
• Detection of relativistic outflows without
  imaging or line identifications
• New technique for distance determination of
  binary sources
• Chandra imaging FFT analysis
• Data analysis with international space missions
• Chandra, XMM-Newton, XTE, ASCA, BATSE, etc
• X-ray binaries, galaxies, gamma-ray bursts, AGNs,
  jets/outflows
• Virtual Observatories
• Data archiving and data mining
• Network optical telescope
• multiwavelength monitoring of transient high
  energy sources

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PDS in time domain and with FFT
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Neutron star low mass X-ray binaries
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Cygnus X-1 black hole binary
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Burst light curve in different bands
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Theoretical Projects on High Energy Astrophysics
at Peking University
1. Inverse Compton Scattering Model for Pulsar
Radiation (lead by Prof. G.J. Qiao) The proposed
beams and cones can naturally explain the
observed pulse profile polarization properties
of pulsars 2. Bared Strange Stars (lead by Dr.
R.X. Xu) Discussing the possibility, related
physics and consequences of the idea if some
pulsars are stars consisting of strange matters
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Theoretical Projects on High Energy Astrophysics
at Peking University

• 3. Accretion Disk Physics (lead by Prof. X.-B.
  Wu) Stability of the advection-dominated
  accretion flow naturally explains the inactive
  feature of nearby galaxies and X-ray binaries in
  low state.
• 4. Binary Black Hole Model in AGNs (lead by Dr.
  F.K. Liu) The interaction of secondary black
  hole with accretion disk around the primary black
  hole may explain the observed periodic variations
  and discontinuity of jet formation in radio-loud
  AGNs

Standard thin disk
ADAF thin disk
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Nanjing

• Nanjing University
• Nanjing Purple Mountain Observatory, Chinese
  Academy of Sciences
• gamma-ray bursts
• solar flares

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High Energy Astrophysics Research at Nanjing
University

• Non-thermal emission of supernova remnants and
  their evolution
• Morphology, structure and composition of
  supernova remnants
• Identification of historical supernova remnants
• Supernovae and binary evolution
• High energy radiation from compact stars
• Gamma-ray bursts

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The Relation for SNRs

• By analyzing Einstein data for SNRs, Zhen-Ru Wang
  at NJU, cooperating with F. Seward at CfA, found
  an important empirical relation between the X-ray
  luminosity of SNRs and the rotational energy loss
  rate of the pulsars inside.

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• This relation, sometimes called Seward-Wang
  relation, is widely recognized and confirmed by
  observations with various X-ray satellites.

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Gamma-Ray Sources and Guest Stars

• On the basis of the fact that the youngest
  neutron stars emit strong gamma-ray radiation,
  Zhen-Ru Wang at NJU suggested that a few
  gamma-ray sources may be identified with young
  compact sources formed in the events of guest
  stars. One of such sources, 2CG 353 16 was
  identified with guest stars observed in the 14th
  century B.C.

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Chandra Observation of the Crab like SNR G21.5-0.9

• Yang Chen at NJU presents the first evidence for
  the presence of an X-ray extended halo
  surrounding the Crab-like core G21.5-0.9.

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Supersoft X-ray Sources and Progenitors of SN Ia

• Calculations of the evolution of white dwarfs in
  binaries by Xiang-Dong Li at NJU lend support to
  the connection between supersoft X-ray sources,
  first observed with ROSAT, and the progenitors
  of SN Ia, and suggest possible distributions of
  the latter.

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Is 4U 1728-34 a Strange Star?

• With the RXTE observations of the kilo-Hertz QPOs
  in 4U1728-34, Xiang-Dong Li at NJU suggested that
  the equation of state of the compact star is more
  compatible with a strange star rather a neutron
  star.

Allowed region
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Generic Model v-R Dynamical Evolution

• Solid
• generic model
• Dash-dotted
• ultra-relativistic
• Dashed
• Newtonian

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GRB Environments
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Meaning of Environmental Effects

• 1stWind Effects Wind environments
• were provided by the progenitor of the GRB
• 2ndDensity Effects Dense environments
• were probably molecular clouds
• GRB is associated with stellar forming region

The existence of two kinds of environmental
effects both support the view GRBs were
originated from the collapse of massive stars
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GRB Energy Source
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• Energy Source Models
• Merger of NS-NS, NS-BH (Eichler et al., 1989
  Paczynski, 1991)
• ?? 108 yr
  (Gravitational radiation timescale)
• Massive star collapse (Woosley, 1993
  Paczynski, 1998)
• ?Association with Star Forming Regions
• ?Association with supernovae
•  Phase Transition of NS?SS
• (Cheng-Dai, PRL, 1996 Dai-Lu, PRL, 1998)
• Natural ways to avoid baryon contamination
• ?A strange star
• ?A rapidly rotating
  Black Hole Disk
• 
  ? ?
• Maximum available energy
  29 MBHc2 42 Mdiskc2
• (through Blandford-Znajek mechanism)
  spin energy binding energy

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Shanghai

• Shanghai Jiao-Tong University
• Shanghai Observatory, Chinese Academy of Sciences
• Bl Lac objects (VLBI observations)
• Accretion disk and outflows
• High energy radiation mechanisms

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Shanghai Jiao-Tong University
X-ray Imaging Study of Elliptical Galaxies with
Chandra 1. Distributions of gas and
gravitating mass ?Constraint on the
ellipticity and the mass profile of dark halos
2. Mass-to-light ratio baryon fraction
?Comparison with theories N-body
simulations 3. Comparison with clusters of
galaxies Xu et al. (ongoing) Cerenkov
Radiation as the Origin of the Iron K Line in
AGNs You et al. 2002 Resonant Inverse
Compton Scattering of Fast Electrons in an
Intense Magnetic Field You et al. 2002
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Kunming, Yunnan

• Yunnan Observatory, Chinese Academy of Sciences
• Yunnan University

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High Energy Astrophysics Activity in Yunnan
Observatory

• Periodic brightness minima and implications for
  binary pair of supermassive black holes in GeV
  QSO PKS1510-089.
• Searches for optical short timescale variations
  in gamma-ray loud blazars.
• Supermassive black holes in gamma-ray loud
  blazars masses, rotations, and emission regions.
• Development of AGN model

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Astrophysical Center in Yunnan University

• The Astrophysical Center in Yunnan University
  was formally established in December 1998. The
  current research interests are high-energy
  radiation from both pulsars and Active Galactic
  Nuclei (AGNs).

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Gamma-Ray Pulsars

• Dr. Zhang and his collaborator, Prof. K.S.
  Cheng (HKU), have made a detailed study in
  high-energy emission from rotation-powered
  pulsars. They proposed a self-consistent outer
  gap model (Zhang Cheng, 1997, ApJ, 487, 370),
  and developed a three-dimensional outer gap model
  (Cheng, Ruderman Zhang, 2000) for explaining
  the observed features of gamma-ray pulsars.

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AGNs

• High-energy radiation from blazars (Zhang Cheng
  1997, ApJ, 475, 534 Zhang Cheng 1997, ApJ,
  488,94 Fan, Cheng Zhang ,1999, AA, 352, 32)
• Gamma-ray and multi-waveband emission from
  blazars (Cheng, Zhang, Zhang, 2000, ApJ, 537,
  80 Zhang, Cheng Fan, 2001, PASJ, 53, 207
  2002, PASJ, 54, 159 Mei, Zhang Jiang, 2002,
  AA)
• Polarization and variations (Fan, Cheng, Zhang,
  et al. 1997, AA, 327, 947 Fan, Cheng Zhang,
  2001, PASJ, 53, 201 Fan et al. 2002, AA, 381,1)

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Introduction
Guangzhou University

• Center for Astrophysics
• Guangzhou University

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• Summary
• 1) Estimate the central black hole masses of
  high-energy gamma-ray loud blazars
• 2) Investigate the high-energy gamma-ray
  emission mechanism
• 3) The variability properties of blazars
• 4) The beaming model for blazars
• 5) The long-term variation periodicity analysis

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Central black hole masses of gamma-ray loud
blazars

• 1) Assumed the gamma-rays are from a 200R_g
  distance from the center black holes and used the
  short time scales in the gamma-ray regions, the
  intrinsic luminosities of the gamma-ray loud
  blazars, the black hole masses of (1-7)107 M??

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Correlation Analysis for Gamma Ray Loud Blazars

• 1) The high frequency (230GHz) radio emissions
  are correlated with the GeV gamma-ray emissions
  with a chance probability of 510-3 , but the
  lower frequency (5GHz) radio emissions do not
  show this kind of correlation, suggesting that
  the high frequency radio emissions are important
  for high energy GeV gamma-ray emissions.
• 2) From the available emission lines and
  gamma-ray emissions, we found that there is no
  clear correlation between the emission line
  emission and the high-energy GeV gamma-ray
  emissions. This analysis does not conflict with
  the synchrotron self-compton model for the
  gamma-ray emsissions.

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Other Instututions

• Hefei University of Science and Technology of
  China, Chinese Academy of Sciences
• AGN multiwavelength studies
• Accretion disk theoretical modeling and X-ray
  data analysis
• Jets/outflows
• Wuhan
• Central China Normal University
• Accretion disk theories
• Central China University of Science and
  Technology
• B-Z mechanism and General relativity
• Urumqi Radio Astronomy Station radio pulsars
• Xiamen Xiamen University
• Accretion disk theories ADAF