Koji. S. Kawabata

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The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been(More)
The unusual helium-rich (type Ib) supernova SN 2005E is distinguished from all supernovae hitherto observed by its faint and rapidly fading light curve, prominent calcium lines in late-phase spectra and lack of any mark of recent star formation near the supernova location. These properties are claimed to be explained by a helium detonation in a thin surface(More)
Late phase nebular spectra and photometry of Type Ib Supernova (SN) 2005bf taken by the Subaru telescope at ∼ 270 and ∼ 310 days since the explosion are presented. Emission lines ([OI] λλ6300, 6363, [CaII] λλ7291, 7324, [FeII] λ7155) show the blueshift of ∼ 1, 500 − 2, 000 km s. The [OI] doublet shows a doubly-peaked profile. The line luminosities can be(More)
Aims. We present and analyse late-time observations of the type-Ib supernova with possible pre-supernova progenitor detection, iPTF13bvn, taken at ∼300 days after the explosion, and discuss these in the context of constraints on the supernova’s progenitor. Previous studies have proposed two possible natures for the progenitor of the supernova, i.e. a(More)
We present results of our intra-night optical flux monitoring observations of S5 0716+714 done simultaneously in g, RC and IC filters. The observations were done using Multicolor Imaging Telescopes for Survey and Monstrous Explosions (MITSuME) instrument on the 50 cm telescope at the Okayama Astrophysical Observatory over 30 nights between 11 March 2008 and(More)
Spectroscopic and spectropolarimetric observations of SN 2003dh/GRB 030329 obtained in 2003 May using the Subaru 8.2 m telescope are presented. The properties of the SN are investigated through a comparison with spectra of the Type Ic hypernovae SNe 1997ef and 1998bw. (Hypernovae being a tentatively defined class of SNe with very broad absorption features:(More)
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