Tomotsugu Goto

(National Tsing Hua University)

Long Gamma-Ray Bursts (hereafter GRBs) are one of the most energetic phenomena in the Universe, known as explosions of massive stars. The bright gamma-ray and afterglow emissions allow us to detect GRBs at cosmic distances such as ~10 billion light-year.  The gamma-ray also can penetrate star-forming regions strongly hidden by dust, which is not possible to trace by current optical galaxy surveys. Therefore the event rate of GRBs could provide with a breakthrough of understanding the ”true” cosmic star-formation history in the Universe.

For this purpose, it is necessary to understand what kind of galaxies and star formations are traced by GRBs especially at the distant Universe. However, star-formation rate (SFR) of distant GRB host galaxies are poorly constrained so far, because accurate SFR measurements require rest frame far-infrared (FIR) detection that is difficult for distant galaxies in general. This problem prevents us from understanding the true cosmic star-formation history implied from GRBs. To overcome this problem, students will use ALMA data of distant GRB host galaxies (up to 7 galaxies) in this project.  Only ALMA has a capability to measure rest-frame FIR luminosity of distant GRB host galaxies. Final goals of the project are accurate measurements of SFR of GRB host galaxies from ALMA data and revealing true cosmic star-formation history.