Upgrade plan of the MOA 1 8 m

Upgrade plan of the MOA 1. 8 -m telescope F. Abe MOA collaboration 19 Jan. 2009, 13 th Microlensing Workshop @ Paris

Discovery of Neptune • In 1846, a mathematician of Observatoire de Paris, Le Verrier predicted a new planet • Independent prediction was made by Adams, UK • Then, Neptune was discovered by Galle at Berliner Sternwarte as per their predictions Urbain Jean Joseph Le Verrier Predictions were essential John Couch Adams

Discovery of OGLE 2005 -BLG-390 Lb Unpredictable Beauliu, et al. , 2006

Discovery of MOA 2007 -BLG-192 Lb Single lens light curve MOA high-cadence observations OGLE observations Bennett, et al. , 2007

Real time　detection of anomaly OGLE 2007 -BLG-368/MOA 2007 -BLG-308 Sumi, et al. , this WS

Short timescale events (MOA 2006 -BLG-98) t. E ~ 1 day Caused by very low-mass star(? ): Free-floating planets (? ) Brown dwarfs (? ) Kamiya, et al. , this WS

Current MOA telescope & CCD Camera • Installed at Mt. John, Observatory, NZ in 2004 • Aperture: 1. 8 m • FOV: 2. 18 4 corrector lenses degree^2 2 degree image circle • Seeing > 1. 5” • 1 observation/hour Plan of upgrade to get wider FOV Sako et al. , 2008

Optical design (by A. Rakich): Requirements & compromise • Requirements – FOV: as wide as possible – Primary mirror: use present mirror – No aspheric lens – No special low-dispersion glasses • Compromise – Replace corrector lenses – Throw out short wavelength (U, B) – Circular effective area

New corrector lenses (4 degree) All spherical surfaces 3 -4 layer coating FQ BK 7 f/2. 96 4 deg ~ 12 deg^2 BK 7 Vessel Window f/2. 91 2 deg. By A. Rakich

Spot diagram (I) 30μm ~ 1. 16” 4 degree Image circle ~12 deg^2

Spot diagram (V) Target FOV: ~ 10 deg^2

Possible CCD layout Image circle 4 degree in diameter CCD chip 3 cm x 6 cm 0. 33°x 0. 66° Total: 52 chips 11. 3 deg^2 5 -6 observations/hour Factor 5 improvement Honeycomb scan

Honeycomb survey (example) 1 2 3 Seamless survey can be made 6 5 4 without overlap 7 8 9

CCD chips & Electronics • Current CCDs – – E 2 V CCD 4882 2 k X 4 k, 3 cm x 6 cm Back illuminated QE: > 90% (500 nm), ~30% (900 nm) • Astronomical Research Camera Gen III • Hamamatsu CCDs for SUBARU – S 10892 -01 HSC – 2 k X 4 k, 3 cm X 6 cm – Back illuminated, 　full depletion (developed by LBNL) – QE: ~90% (600 -850 nm) >80% (900 nm) – Factor 2 improvement • Astronomical Research Camera Gen III

Time schedule Oct 30 Apr 1 July Installation R&D, cost estimate Proposal Blanks Lenses CCDs etc. Camera Polish assemble Assemble Tests High quality alert: ~ 2013 Tests Science Observations 2009 2010 2011 2012

Summary • High-cadence observations using wide FOV are essential in new generation microlensing planet search • MOA Group is planning to upgrade existing 1. 8 m telescope to get ~ 10 deg^2 FOV • Design of the new optics has been done. • Technical studies of the CCD camera are going to start to solve several problems • After several technical studies and cost estimate, we will submit the first proposal in this October. • If it’s approved, observation will be started in the 2012 bulge season

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