Transcript Review of High Energy Astrophysics Research in Mainland

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
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
2
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
3
Urumqi
Kunming Guangzhou Wuhan Beijing Hefei Nanjing Xiamen
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
Shanghai
4
Urumqi
Kunming Guangzhou Wuhan Beijing Hefei Nanjing Xiamen
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
Shanghai
5
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
6
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 R&D
- Observations and data analysis
• black hole and X-ray binaries, AGNs, gamma-ray bursts,
supernova remnants, pulsars
- Theoretical astrophysics
• Accretion disks, gamma-ray bursts
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
7
YBJ International Cosmic Ray Observatory
Tibet -Lhasa: 4300 m asl
China-Japan: AS-
China-Italy: ARGO
Cosmic-ray
High Energy Gamma-ray
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
8
ARGO-YBJ
• China-Italy
• @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 @ 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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
9
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
10
Morphology
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
11
Model: Close Cousin to the Crab Nebula
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
12
Doppler boosting model for the ring
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
13
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 widefield X-ray camera
– Tubingen University (Germany): to provide electronics, data acquisition
– University of Southampton (UK): mission optimization, space environments
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
14
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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
15
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
16
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
17
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
18
PDS in time domain and with FFT
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
19
Neutron star low mass X-ray binaries
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
20
Cygnus X-1: black hole binary
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
21
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
22
Burst light curve in different bands
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
23
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
24
Theoretical Projects on High Energy
Astrophysics at Peking University
3. Accretion Disk Physics (lead by Prof.
X.-B. Wu): Stability of the advectiondominated 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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
25
Nanjing
• Nanjing University
• Nanjing Purple Mountain Observatory, Chinese Academy of
Sciences
– gamma-ray bursts
– solar flares
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
26
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
27
The Lx
 E 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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
28
This relation, sometimes called “Seward-Wang relation”, is
widely recognized and confirmed by observations with
various X-ray satellites.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
29
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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
30
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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
31
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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
32
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
33
Generic Dynamic Model for
GRB afterglow
d
 2 1

dm
M

d
 2 1

dm
M ej  m  2(1   )m
(Y.F. Huang, Z.G. Dai, T. Lu, 1999)
It gives the overall description from ultra-relativistic and
highly radiative phase to non-relativistic and adiabatic phase,
especially leads to the correct Sedov limit:
β ∝ R-3/2,
as the fireball getting into the non-relativistic and adiabatic
phase.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
34
Generic Model: v-R
Dynamical Evolution
• Solid:
generic model
• Dash-dotted:
ultra-relativistic
• Dashed:
Newtonian
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
35
GRB Environments
Non-uniform Environment of GRB
n ~ r-k
GRB970616


n ~ r-2
(wind environment)
(Dai, Lu, 1998)
Support the view of massive star origin for GRBs.
(Chevaliar, Li, 1999)
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
37
Dense Environment
·
Break in optical light curve of GRB990123:
n～106 cm-3
(Relativistic to non-relativistic transition  break)
Dai-Lu, ApJL, 1999
· Rapidly declining optical to X-ray afterglow of GRB980519
can be explained well by dense medium, and its radio
afterglow can also be excellently explained.
Wang-Dai-Lu, MNRAS, 2000
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
38
Meaning of Environmental Effects
•1st：Wind Effects Wind environments
were provided by the progenitor of the GRB
•2nd：Density 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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
39
GRB Energy Source
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
41
Phase Transition of NS  SS
(one way avoiding baryon-contamination)
 Energy: Phase Transition
～ 20 MeV/baryon
Rotation Energy
～ 5×1051 ergs I44Ω4
 Baryon only in thin Crust
～ 10-5 M⊙
 Multi-sub-bursts --- Differential Rotations
 Rate of Accreting NS in LMXB to SS ～ 10-6/yr per galaxy
(Dai, Lu, PRL, 1998; Cheng, Dai, PRL, 1996)
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
42
Shanghai
– Shanghai Jiao-Tong University
– Shanghai Observatory, Chinese Academy of Sciences
- Bl Lac objects (VLBI observations)
- Accretion disk and outflows
- High energy radiation mechanisms
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
43
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
44
Kunming, Yunnan
• Yunnan Observatory, Chinese Academy of Sciences
• Yunnan University
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
45
High Energy Astrophysics Activity in
Yunnan Observatory
• Periodic brightness minima and implications for binary
pair of supermassive black holes in GeV QSO PKS1510089.
• Searches for optical short timescale variations in gammaray loud blazars.
• Supermassive black holes in gamma-ray loud blazars:
masses, rotations, and emission regions.
• Development of AGN model
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
46
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).
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
47
 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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
48
 AGNs
 High-energy radiation from blazars (Zhang &Cheng 1997, ApJ,
475, 534; Zhang &Cheng 1997, ApJ, 488,94; Fan, Cheng & Zhang ,1999,
A&A, 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, A&A)
 Polarization and variations (Fan, Cheng, Zhang, et al. 1997, A&A,
327, 947; Fan, Cheng &Zhang, 2001, PASJ, 53, 201; Fan et al. 2002, A&A,
381,1)
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
49
Introduction
Guangzhou
University
Center for Astrophysics
Guangzhou University
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
50
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
51
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。
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
52
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 5*10-3 ,
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.
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
53
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
July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan
54