Upgrade plan of the MOA 1.8-m telescope F. Abe MOA collaboration 19 Jan. 2009, 13th Microlensing 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 John Couch Adams Predictions were essential

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

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

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

Current MOA telescope & CCD Camera Installed at Mt. John, Observatory, NZ in 2004 Aperture: 1.8 m FOV: 2.18 degree^2 Seeing > 1.5” 1 observation/hour 4 corrector lenses 2 degree image circle 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) By A. Rakich f/ deg ~ 12 deg^2 f/ deg. BK7 FQ Vessel Window 3-4 layer coating All spherical surfaces

Spot diagram (I) 30μm ~ 1.16” 4degree Image circle ~12deg^2

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

Possible CCD layout Image circle 4 degree in diameter CCD chip 3cm x 6cm 0.33°x 0.66° Total: 52 chips 11.3 deg^2 5-6 observations/hour Factor 5 improvement Honeycomb scan

Honeycomb survey (example) Seamless survey can be made without overlap

CCD chips & Electronics Current CCDs –E2V CCD4882 –2k X 4k, 3cm x 6cm –Back illuminated –QE: > 90% (500nm), ~30% (900nm) Astronomical Research Camera Gen III Hamamatsu CCDs –S –2k X 4k, 3cm X 6cm –Back illuminated, full depletion (developed by LBNL) –QE: ~90% ( nm) >80% (900nm) –Factor 2 improvement Astronomical Research Camera Gen III for SUBARU HSC

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

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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