review of high energy astrophysics research in mainland china zhang, shuang nan key lab for particle...

Review of High Energy Astrophysics Research in Mainland

ChinaZhang, Shuang Nan

Key Lab for Particle AstrophysicsInstitute of High Energy PhysicsChinese Academy of Sciences

National Space Science Technology Center (NSSTC)and Physics Department

University of Alabama in Huntsville, AL, USA

Tsinghua Center for Astrophysics (THCA)and Physics Department

Tsinghua University, Beijing, China

July 6, 2002, IAU Regional Meeting, Satellite Meeting on High Energy Astrophysics, Tokyo, Japan 2

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


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


Urumqi Kunming Guangzhou Wuhan Beijing Hefei ShanghaiNanjing Xiamen


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


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


Tibet -Lhasa: 4300 m asl

China-Japan: AS-

China-Italy: ARGO

Cosmic-ray

High Energy Gamma-ray

YBJ International Cosmic Ray Observatory


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


Morphology


Model: Close Cousin to the Crab Nebula


Doppler boosting model for the ring


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


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.


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


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


PDS in time domain and with FFT


Neutron star low mass X-ray binaries


Cygnus X-1: black hole binary


Burst light curve in different bands


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


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


Nanjing

• Nanjing University

• Nanjing Purple Mountain Observatory, Chinese Academy of Sciences– gamma-ray bursts

– solar flares


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


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.

EL x


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


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.


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.


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.


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


G e n e r i c D y n a m i c M o d e l f o r

G R B a f t e r g l o w

Mm

1

d

d 2

mmMm

)1(2

1

d

d

ej

2

( Y . F . H u a n g , Z . G . D a i , T . L u , 1 9 9 9 )

I t g i v e s t h e o v e r a l l d e s c r i p t i o n f r o m u l t r a - r e l a t i v i s t i c a n d

h i g h l y r a d i a t i v e p h a s e t o n o n - r e l a t i v i s t i c a n d a d i a b a t i c p h a s e ,

e s p e c i a l l y l e a d s t o t h e c o r r e c t S e d o v l i m i t :

β ∝ R - 3 / 2 ,

a s t h e f i r e b a l l g e t t i n g i n t o t h e n o n - r e l a t i v i s t i c a n d a d i a b a t i c

p h a s e .


Generic Model: v-R Dynamical Evolution

• Solid:

generic model

• Dash-dotted:

ultra-relativistic

• Dashed:

Newtonian

GRB GRB EnvironmentsEnvironments


Non- uniform Environment of GRB

GRB970616 n ~ r-k

n ~ r-2 (wind environment)

(Dai, Lu, 1998)

Support the view of massive star origin for GRBs. (Chevaliar, Li, 1999)


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


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

GRB Energy GRB Energy SourceSource


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


Phase Transition of NS SS (one way avoiding baryon-contamination)

Energy: Phase Transition ～ 20 MeV/baryon

Rotation Energy ～ 5× 1051 ergs I44Ω 4

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)


Shanghai

– Shanghai Jiao-Tong University

– Shanghai Observatory, Chinese Academy of Sciences

- Bl Lac objects (VLBI observations)

- Accretion disk and outflows

- High energy radiation mechanisms


• 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

Shanghai Jiao-Tong University


Kunming, Yunnan

• Yunnan Observatory, Chinese Academy of Sciences

• Yunnan University


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


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).


Gamma-Ray PulsarsGamma-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 modelouter 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.


AGNsAGNs

High-energy radiation from blazarsHigh-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 blazarsGamma-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 variationsPolarization 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)


Introduction

Center for Astrophysics

Guangzhou University

Guangzhou University


Summary:1) Estimate the central black hole masses of high-energy gamma-ray

loud blazars2) Investigate the high-energy gamma-ray emission mechanism3) The variability properties of blazars4) The beaming model for blazars5) The long-term variation periodicity analysis


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。


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.


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

review of high energy astrophysics research in mainland china zhang, shuang nan key lab for particle...

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