Li-Jun Gou
Penn State
University Astronomy & Astrophysics
My research interests focus on Gamma-Ray Bursts
(GRBs), the brightest explosions in the Universe, which shine at
us across billions of years of cosmic history. In particular, I have
investigated the evolution of burst properties with redshift,
inverse-Compton effects in GRBs, and the application of high-redshift
GRB afterglows to cosmology.
I am currently a PhD candidate in the Astronomy & Astrophysics
Department. I am anticipated to receive my PhD in Aug. 2007. My
advisor is Professor Peter
Mészáros. I am also partly working with Professor Derek B.
Fox. Before coming to Penn State in 2001, I obtained my
B.S. and M.S. Degrees on astronomy at Nanjing University, China. In my
Master's thesis I investigated GRB behavior through theoretical
models, considering the effects of varying circumburst density
profiles, anisotropic energy distributions, and collimated ejecta.
Curriculum Vitae:
Current Projects:
- GLAST
Prospects for Swift-Era Afterglows, Gou & Mészáros 2007, ApJ in press (astro-ph)
We explore the
detectability of GeV emission from gamma-ray burst afterglows with the
upcoming GLAST mission, addressing the
interesting question: What is the most distant burst that can be
detected by GLAST?
- Modeling GRB
050904: Autopsy of a Massive Stellar Explosion at z=6.29, Gou, Fox
& Mészáros 2007, ApJ in press (astro-ph)
We
explore the physical parameters of the highest-redshift gamma-ray
burst, GRB 050904, which occurred at redshift z=6.29 when the Universe
was one billion years old, using sophisticated theoretical models and
Monte Carlo Markov Chain (MCMC) method.
Refereed Publications:
- Detectability
of Gamma-Ray Burst Iron Lines by Swift, Chandra, and XMM-Newton,
Gou, Mészáros & Kallman 2005, ApJ, 624, 889 (astro-ph)
Identifying the redshift of the objects is always one of the key
questions in astronomical research, we examine the potential
feasibility of measuring the GRB redshift with the X-ray iron-line by
the current satellites: Swift, Chandra and XMM-Newton. - Detectability
of Long Gamma-Ray Burst Afterglows from Very High Redshifts, Gou,
Mészáros, Abel & Zhang 2004, ApJ, 604, 508 (astro-ph)
Photons from GRBs located in the distant universe can tell us the
history of the Universe, and how far GRBs can trace the Universe back
with the current and upcoming telescopes: Chandra, Swift, XMM-Newton
and James Webb Space Telescope? Our paper has addressed the
interesting question.
- GeV Emission
from TeV Blazars and Intergalactic Magnetic Fields, Dai,
Zhang, Gou, Mészáros & Waxman 2002, ApJL, 580, L7 (astro-ph)
The
energetic TeV photons can be absorbed by diffuse IR background
photons, yielding electron-positron pairs. Meanwhile, the
electron-positron pairs can inverse-Compton scatter Cosmic Microwave
photons to GeV energy band. We predict the photon spectrum, produced
via this process, for TeV Blazars . - Gamma-Ray
Burst Afterglows from Anisotropic Jets, Dai & Gou 2001, ApJ,
552, 72 (astro-ph)
Simulations on GRB progenitors show that the energy distribution
within the collimated ejecta is not uniform, and follows some power
law. We calculate the light curve and spectra for GRB afterglows when
ejecta expands in various circumburst density environment. - Gamma-ray
burst afterglows from jetted shocks in wind environments, Gou,
Dai, Huang & Lu 2001, A&A, 368, 464 (astro-ph)
Observations show that the GRB ejecta is collimated. Considering an
alternative density environment, wind environment, in contrast to the
uniform circumburst density, we calculate the light curve of the GRB
afterglows. - Overall
Evolution of Jetted Gamma-Ray Burst Ejecta, Huang, Gou, Dai &
Lu 2000, ApJ, 543, 90 (astro-ph)
Using
the proper dynamic equations which can describe the smooth transition from
relativistic stage to non-relativistic stage and incorporating some
new observational elements, e.g., collimated ejecta, into our
theoretical model, we numerically investigate the evolution of GRB
afterglows in a uniform circumburst density.
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