NOGAMI, Daisaku, D. Sc. (Kyoto Univ.), Astrophysics

I have been doing research of astronomical objects which show various
dramatic variabilities, mainly by photometric and spectroscopic
observations in optical, using a 60-cm reflector at the Hida observatory,
the 8.2-m SUBARU telescope, and so on.  The targets are such as
cataclysmic variable stars, X-ray binaries, gamma-ray bursts, and
flare stars.  The engine of the variabilities in X-ray binaries and
cataclysmic variables is the accretion disk in most cases.  By
analyzing changes of the spectral feature, and the timescale and
the amplitude of oscillations, the temperature and the density
structure in the accretion disk can be deduced, which leads to
new understandings of the accretion disk physics.  The progenitor
of the gamma-ray burst is one of the mysteries left to be solved
in the modern astrophysics.  Optical and multi-wavelength observations
of the afterglow from the very initial phase may provide hints on the
problem.  Flare stars have been recently attracting researchers'
attention with the flare mechanism in the Sun being elucidated.  It
is an interesting topic to examine how applicable the understandings
of flares in the Sun are to the gigantic flares in the flare stars
and make clear the differences between flares in the flare stars and
the Sun.

Recent Papers (2001-2003)

Nogami, D., et al., 2003, A&A, 404, 1067
"In-the-gap SU UMa-type dwarf nova, Var73 Dra with a supercycle of
about 60 days"

Nogami, D., Kato, T., Baba, H., 2002, PASJ, 54, 987
"Time-Resolved Photometry of GK Persei during the 1996 Outburst"

Uemura, M., et al., 2003, Nature, 423, 843
"Structure in the early afterglow light curve of the
gamma-ray burst of 20 March 2003"

Baba, H., et al., 2002, PASJ, 54, L7
"Spiral Structure in WZ Sagittae around the 2001 Outburst Maximum"

Nogami, D., et al., 2001, MNRAS, 322, 79
"A normal and superoutburst study of the eclipsing SU UMa star:
DV Ursae Majoris"