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Professor
Chang,Hsiang-Kuang

 
Personal Website
Office¡G886-3-5742952(PHYS R711)
Laboratory¡GHigh Energy Astrophysics Group
Lab Tel¡G886-3-5742953 (PHYS R710)
Fax¡G886-3-5723052
E-mail¡Ghkchang@phys.nthu.edu.tw

Education
  1. 1991-1994 Ph.D. in AstroPhysics, Bonn University, German
  2. 1989-1991 M.S. in Physics, National Taiwan University, R.O.C.
  3. 1983-1987 B.S. in Physics, National Tsing Hua University, R.O.C.
Professional Experience
Current position¡G
  1. 2006.8-present, Professor of Physics, National Tsing Hua University
Experience¡G
  1. 2000-2006, Associate Professor of Physics, National Tsing Hua University, R.O.C.
  2. 1997-2000, Assistant Professor of Physics Dept., National Tsing Hua University, R.O.C.
  3. 1996-1997, Postdoctoral research fellow of Physics Dept., National Tsing Hua University, R.O.C.
  4. 1994-1996, Postdoctoral research fellow of Nonproliferation and International Security Division, Los Alamos National Laboratory, U.S.A.
Research Fields
    1. AstroPhysics
Research Interests and achievement
Updated on September 3, 2006
Currently research topics in my group, the High Energy Astrophysics Group, include the following ones:
(1) The Nuclear Compton Telescope (NCT) project :
The NCT project is a joint effort of several institutions in Taiwan and in US. The NCT is a balloon-borne telescope designed to study astrophysical sources of MeV gamma-ray emission with high spectral resolution, moderate angular resolution, and novel sensitivity to gamma-ray polarization. The heart of NCT is an array of novel cross-strip germanium detectors, each of 15-mm thickness and 5400 mm^2 active area, with full 3D position resolution < 2 mm^3. NCT will perform Compton imaging in the 0.2-10 MeV gamma-ray band. We are currently planning a 12-detector long duration balloon flight of the NCT instrument from Australia in December 2008. Major scientific topics of this project include the galactic 511-keV line emission, origin of Al-26, and polarization of gamma-ray emission from pulsars, etc. :
(2) X-ray occultation of Trans-Neptunian Objects (TNOs) :
We have discovered, for the first time in astronomy, X-ray occultation events caused by TNOs. These events were found in the RXTE/PCA X-ray light curve of Sco X-1 at millisecond time scales. It opens up a new window for TNO surveys, particularly for the smallest, most abundant TNOs. The implication to the distribution of TNOs is being studied. It also provides a possible way of resolving the X-ray emitting region in compact stars with the technique of X-ray occultation. :
(3) Isolated Neutron Stars (INSs) :
Isolated neutron stars exhibit themselves in many different ways, like most radio pulsars, gamma-ray pulsars, Anomalous X-ray Pulsars (AXPs), Soft Gamma Repeaters (SGRs), and some isolated X-ray sources. Some of them may have extremely strong magnetic fields of 10^15 G, dubbed ¡¥magnetars¡¦. Some of them might be in fact ¡¥quark stars¡¦. Most of them show various kinds of emission mechanisms in their magnetospheres. We study these sources in both theoretical and observational aspects.
Selected Publications
  1. [2006] H.-K. Chang, S.-K. King, J.-S. Liang, P.-S. Wu, L. C.-C. Lin, C.-J. Chiu Occultation of X-rays from Scorpius X-1 by Small Trans-Neptunian Objects, Nature 442, 660 (2006)
  2. [2006] J. Takata, S. Shibata, K, Hirotani, H.-K. Chang A Two-dimensional Electrodynamical Outer Gap Model for Gamma Ray Pulsars: Gamma-ray Spectrum ,MNRAS 366, 1310 (2006)
  3. [2004] H.-K. Chang , Thermal Flux Fractions of Anomalous X-ray Pulsars RX J170849-400910 and 4U 0142+61,CJP 42, 135 (2004)
  4. [2002] H.-K. Chang, Electrostatic Corrections to the Equation of State for a Fully Ionized Hydrogen Atmosphere of Magnetic Neutron Stars, CJP 40, 395 (2002)
  5. [1999] H.-K. Chang, D.-Y. Chou, M.-T. Sun., In Search of Emerging Magnetic Flux underneath the Solar Surface with Acoustic Imaging, ApJ 526, L53 (1999)
  6. [1997] H.-K. Chang , D.-Y. Chou, B. LaBonte, the TON team, Ambient Acoustic Imaging in Helioseismology , Nature 389, 825 (1997)
  7. [1997] H.-K. Chang, C. Ho, RXTE Observation of PSR B1951+32 , ApJ 479, L125 (1997)
  8. [1995] H.-K. Chang, Magnetic Inverse Compton Scattering above Polar Caps , A&A 301, 456 (1995)
    • All Publications (Expansible)

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