94 citations · 165 across the 5 of their papers we have counts for
7 papers · 1 filter
Testing the External Shock Model of Gamma-Ray Bursts using the Late-Time Simultaneous Optical and X-ray Afterglows
Yuji Urata, Ryo Yamazaki, Takanori Sakamoto +21
We study the ``normal'' decay phase of the X-ray afterglows of gamma-ray bursts (GRBs), which follows the shallow decay phase, using the events simultaneously observed in the R-ban…
Multi-color Shallow Decay and Chromatic Breaks in the GRB 050319 Optical Afterglow
K. Y. Huang, Y. Urata, P. H. Kuo +19
Multi-wavelength B, V, R, I observations of the optical afterglow of GRB 050319 were performed by the 1.05-m telescope at Kiso Observatory and the 1.0-m telescope at Lulin Observat…
The period-luminosity relation for type II Cepheids in globular clusters
Noriyuki Matsunaga, Hinako Fukushi, Yoshikazu Nakada +11
We report the result of our near-infrared observations (JHKs) for type II Cepheids (including possible RV Tau stars) in galactic globular clusters. We detected variations of 46 var…
Chemical composition of UV-bright star ZNG 4 in the globular cluster M13
S. Ambika, M. Parthasarathy, W. Aoki +4
We present a detailed model-atmosphere analysis of ZNG 4, a UV-bright star in the globular cluster M13. From the analysis of a high resolution () spectrum of th…
Early (0.3 day) R-band light curve of the optical afterglow of GRB030329
Y. Urata, T. Miyata, S. Nishiura +13
We observed the optical afterglow of the bright gamma-ray burst GRB030329 on the nights of 2003 March 29, using the Kiso observatory (the University of Tokyo) 1.05 m Schmidt telesc…
Variable Stars in the Magellanic Clouds: Results from OGLE and SIRIUS
Yoshifusa Ita, Toshihiko Tanabe, Noriyuki Matsunaga +10
We have performed a cross-identification between OGLE-II data and single-epoch SIRIUS JHK survey data in the LMC and SMC. After eliminating obvious spurious variables, we determine…