Kiso Supernova Survey (KISS): Survey strategy

2 T. Morokuma et al. [Vol. ,AbstractThe Kiso Supernova Survey (KISS) is a high-cadence optical wide-field supernova (SN) survey. Theprimary goal of the survey is to catch the very early light of a SN, during the shock breakout phase.Detection of SN shock breakouts combined with multi-band photometry obtained with other facilitieswould provide detailed physical information on the progenitor stars of SNe. The survey is performed usinga 2.2×2.2 deg field-of-view instrument on the 1.05-m Kiso Schmidt telescope, the Kiso Wide Field Camera(KWFC). We take a three-minute exposure in g-band once every hour in our survey, reaching magnitudeg ∼ 20−21. About 100 nights of telescope time per year have been spent on the survey since April 2012.The number of the shock breakout detections is estimated to be of order of 1 during our 3-year project.This paper summarizes the KISS project including the KWFC observing setup, the survey strategy, thedata reduction system, and CBET-reported SNe discovered so far by KISS.Key words:supernovae: general – surveys – cosmology: observations1. IntroductionThe variable sky has been intensively explored by wide-field surveys such as Palomar Transient Factory (PTF;Rau et al. 2009; Law et al. 2009), Catalina Real-TimeSky Survey (CRTS; Drake et al. 2009), La Silla-QUESTLow Redshift Supernova Survey (Baltay et al. 2013),Mobile Astronomical System of the TElescope-Robots(MASTER; Lipunov et al. 2004), Panoramic SurveyTelescope & Rapid Response System (Pan-STARRS1;Kaiser et al. 2002), SkyMapper (Keller et al. 2007), SDSSStripe 82 Supernova Survey (Frieman et al. 2008; Sakoet al. 2008; Sako et al. 2014), and Deep Lens Survey(DLS; Wittman et al. 2002), with each survey having auniform data quality controlled systematically, especiallyduring the last two decades. Some of the ground-basedlarge aperture and space telescopes also have utilized theirdeep imaging capabilities to explore transient phenom-ena within the scheme of their deep surveys (Sarajedini,Gilliland & Kasm2003; Sarajediniet al. 2006; Cohen et al.2006; Morokuma et al. 2008; Villforth et al. 2010; Groginet al. 2011; Postman et al. 2012). All these projectswere made possible by the recent development of largemosaiced-CCD imaging cameras. However, we still havelittle knowledge of fast transient objects whose time scalesare shorter than a day except for a few classes of objects(e.g., rapidly variable stars such as RR Lyrae). One ofthe most interesting phenomena in this time scale is theshock breakout of a supernova (SN). Although the ex-istence of this phenomenon was theoretically predictedabout 40 years ago (Klein & Chevalier 1978) and manySN surveys have been conducted, there are only threeserendipitous detections so far (SN 2008D in NGC 2770in X-ray; Soderberg et al. 2008; SNLS-04D2dc and SNLS-06D1jd in ultraviolet; Schawinski et al. 2008; Gezari et al.2008) due to the short time scale: just a few hours. Shockbreakouts are one of the brightest phenomena associatedwith SNe and are considered to be associated with everySN. Shock breakouts of SN explosions with hydrogen en-velopes in particular are luminous in the optical and lastfor a few hours by virtue of the large radius of a progenitorstar. They are expected to be a new tool for exploring thedistant universe (Tominaga et al. 2011). In this paper, weshow our new survey optimized for detecting nearby SNshock breakouts.A new wide-field optical imager, the Kiso Wide FieldCamera (KWFC; Sako et al. 2012), for the 1.05-m KisoSchmidt telescope operated by the Institute of Astronomyof the University of Tokyo, in Nagano, Japan, was de-veloped and has been open to public use since April2012, succeeding the former camera 2kCCD (Itoh et al.2001). We started a high-cadence SN survey, called theKiso Supernova Survey (KISS), with KWFC in April2012 within the scheme of the Kiso Observatory LargePrograms. Another program is a search mainly for peri-odic variable stars in the Galactic plane, called the KWFCIntensive Survey Of the Galactic Plane (KISOGP). Theseprogramsare scheduled to be conducted until March 2015.The structure of this paper is as follows. We summarizethe KISS observations including our observing strategyand the data reduction system in §2 and §3, respectively.Our initial results are shown in §4. §5 is a summary ofthe paper. We use the standard ΛCDM cosmological pa-rameters of (H