(Proposal ID) S16B-080

(PI) Yasuda, Naoki

(Proposal Title)
Probing Dark Energy with z>1 SNe Ia from HSC SSP Transient Survey

(Abstract)
Type Ia Supernova is one of the most powerful probes to constrain the dark 
energy. Through the detailed, accurate, and unbiased measurements of its light 
curve it probes the expansion history of the Universe. The existing and on-
going observations of z < 1 sample place strong constraints on rho_{DE}(z) out 
to z~1. At the redshift beyond z > 1, the currnet constraints have little 
statistical strength due to the lack of well-measured SNe Ia at this redshift. 
HSC is an unique instrument to effectively find SNe at this high redshift and 
HSC SSP will start coordinated transient survey from this semestar (S16B). 
In this transient survey which continues for 6 months, we expect to detect 
~70 SNe Ia beyond z > 1. Here, we propose spectroscopic follow-up observation 
of SN+host galaxy detected by this HSC transient survey. The proposed 
observation secures a very high purity of high-z SNe Ia and we plan to execute 
a follow-up observation by the Hubble Space Telescope. We will conduct a 
precise measurement of the color of the high-z SN~Ia in HST IR bands (F105W 
and F140W) and enhance the value of SNe Ia and dobule the Dark Energy Task 
Force's Figure-of-Merit.