The Hyper Suprime-Cam SSP transient survey in COSMOS: Overview

Naoki Yasuda, Masaomi Tanaka, Nozomu Tominaga, Ji An Jiang, Takashi J. Moriya, Tomoki Morokuma, Nao Suzuki, Ichiro Takahashi, Masaki S. Yamaguchi, Keiichi Maeda, Masao Sako, Shiro Ikeda, Akisato Kimura, Mikio Morii, Naonori Ueda, Naoki Yoshida, Chien Hsiu Lee, Sherry H. Suyu, Yutaka Komiyama, Nicolas RegnaultDavid Rubin

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


We present an overview of a deep transient survey of the COSMOS field with the Subaru Hyper Suprime-Cam (HSC). The survey was performed for the 1.77 deg2 ultra-deep layer and 5.78 deg2 deep layer in the Subaru Strategic Program over six- and four-month periods from 2016 to 2017, respectively. The ultra-deep layer reaches a median depth per epoch of 26.4, 26.3, 26.0, 25.6, and 24.6 mag in g, r, i, z, and y bands, respectively; the deep layer is ∼0.6 mag shallower. In total, 1824 supernova candidates were identified. Based on light-curve fitting and derived light-curve shape parameter, we classified 433 objects as Type Ia supernovae (SNe); among these candidates, 129 objects have spectroscopic or COSMOS2015 photometric redshifts and 58 objects are located at z > 1. Our unique data set doubles the number of Type Ia SNe at z > 1 and enables various time-domain analyses of Type II SNe, high-redshift superluminous SNe, variable stars, and active galactic nuclei.

Original languageEnglish
Article number74
JournalPublication of the Astronomical Society of Japan
Issue number4
Publication statusPublished - 2019 Aug 1


  • cosmology: observations
  • supernovae: general
  • surveys


Dive into the research topics of 'The Hyper Suprime-Cam SSP transient survey in COSMOS: Overview'. Together they form a unique fingerprint.

Cite this