Microlensing Observation in Antrophysics MOA searching Dark Mater

Microlensing Observation in Antrophysics (MOA), searching Dark Mater and Extra-Solar planet Nagoya Univ. Solar-Terrestrial Environment Laboratory, Takahiro Sumi

• Light from the source star is bent by the gravity of the lens object like Black hall. • Lens object as though optical lens, magnify the light from background star. Amplification Gravitational Microlensing Earth Time 　　　　Lens Object Star

Point mass lens

Halo Dark Matter • There ~10 times more dark matter than visible mass. • If they are MAssive Compact Halo Object (MACHO), they can be observed by Microlensing.

MACHO project 1. 28 m telescope 1. 8 million stars

First Microlensing event by MACHO & EROS

MACHO 2 years, Alcock et al. 1997

• MACHO 5. 7 years 11. 9 million stars in the LMC reveals 13 -17 microlensing events • 0. 15 ~ 0. 9 M , f=20% 12 events: 16% of the mass of a standard Galactic halo. The detection exceeds the expected background of 2 events expected from ordinary stars in standard models of the Milky Way and LMC at the 99. 98% confidence level. (Bennett 2005)

Eros 5 years, Afonso et al. 400, p. 951 -956 (2003) • Less than 25% of a standard halo can be composed of objects with a mass between 2 x 10 -7 M and 1 M at the 95% C. L.

EROS and MACHO Combined Limits on Planetary-Mass Dark Matter in the Galactic Halo, f<25% of the halo dark matter made of MACHO with 10 -7 -10 -3 M , for most models considered f< 10% for 3. 5× 10 -7 -4. 5× 10 -5 M. Alcock et al. (1998)

(1) MACHO? , Super. Macho (2) disk-bar or bar-bar self-lensing of the LMC? , Super. Macho: 4 m telescope, 1/2 nights per 2 nights for 3 months over 5 years. ~30 events Center Outer

Super. MACHO

MOA 0. 6 m telescope （New Zealand/Mt. John Observatory ） Mirror : 0. 6 m CCD : 4 k　x　6 k pix. FOV : 1. 3 square deg.

MOA-II 1. 8 m telescope （New Zealand/Mt. John Observatory ） At Mt. John Obs. in NZ, 44 S; Mirror : 1. 8 m CCD : 8 k　x　10 k pix. FOV : 2. 2 square deg.

MOA-II LMC field

Optical Gravitational Lensing Experiment (OGLE) Las Campanas Altitude: 2300 m Seeing ~ 1. 3” OGLE-I : 1991~1996 : 1 m, 2 kx 2 k CCD OGLE-II : 1997~2000 : 1. 3 m, 2 kx 2 k CCD, 14’x 14’ OGLE-III: 2001~ : 1. 3 m, 8 kx 8 k mosaic CCD : 35’x 35’ 19 events 500 events 600 events/yr

Difference Image Analysis (DIA)

Extra-Solar planet

1. Doppler method

2. Transit of Planet

2. Transit of Planet OGLE-III GC: 2001, 59 candidates (Udalski et al, 2002) Carina arm: 2002, 78 candiates, (Udalski et al. 2003) total: 137 5 (OGLE-TR-10, 56, 111, 113 and 132) were confirmed by radial velocity (Konacki et al. 2003, 2004, Bouchy et al. 2004, Pont et al. 2004)

3. Astrometry

4. Direct imaging

Extra-Solar planet

Planetary system

Microlensing toward the Galactic Bulge

MACHO-97 -BLG-41 Bennett et al. , 1999, Nature, 402, 57 Data by PLANET collaboration prefer rotating binary

MACHO 98 -BLG-35 Rhie et al. , 2000, Ap. J, 533, 378 q=7 x 10 -5

Possible Planetary Event ＯＧＬＥ-2002 -BLG-055 Jaroszynski & Paczynski 2002, Ac. A, 52, 361 Gaudi & Han, 2004, astro-ph/0402417

Constrain of the abandance of planets Snodgrass et al. , 2004, MNRAS, 351, 967 Detection Probability 321 events in 2002 by OGLEIII a/RE=distance from lens

Constrain of the abundance of planets a/RE Detection Probability 321 events in 2002 by OGLEIII Snodgrass et al. , 2004, MNRAS, 351, 967 Detection Probability in a/RE Detection Probability in a (AU) A　(AU) Cool Jupiter( ) , Np<1/5. 5=18%

PLANET constrain PLANET collaboration followed up 43 events during 5 years 95%c. l. exclusion contours for f=75, 66, 50, 33 and 25% (outer to inner) Albrow et al. , 2001, Ap. JL, 556, 113 Gaudi et al. , 2002, Ap. J, 566, 463

MOA-II Bulge field

First planet via microlensing OGLE 2003 -BLG-235/MOA 2003 -BLG-53 Planet, mass ratio q=0. 0039 OGLE 2003 -BLG-235/MOA 2003 -BLG-53 was detected by the OGLE EWS System on June 22, 2003 and by the MOA group on July 21, 2003. 　

2 nd & 3 rd planets OGLE-2005 -BLG-071. 1 MJupiter , Udalski et al. 2005 OGLE-2005 -BLG-169, 13 MEarth, Gould et al. 2006 “Cool Neptune" planets may be relatively common, with frequency of 16% at 90% confidence.

5 Earth Mass planet (Beaulieu et al. 2006, Nature, 439, 437)

Sensitivety

Summary • MACHO comprise ~16% of Dark Halo • MOA can solve if there is MACHO or not • MOA found 5 Earth mass Extra-Solar Planet • MOA will find an another Earth!

Animation of O 235/M 53

The Idea of binary and planetary event was first　 suggested by Mao & Paczynski, 1991, Ap. JL, 374, 40 RE primary planet Source is at 8 kpc Primary : 1 Mo Secondary: 0. 1, 0. 001 Mo at 4 kpc <caustic>=0. 06 RE, assuming loga=const.

Constraints on the distance to O 235/M 53 and its mass x=Dlens/Dsource Using Main sequence Mass-Luminosity relation, and Flens<Fblend, Dlens<5. 4 kpc(90%c. l. ) Then Likelihood was estimated by using Disk model & Proper motion.

Modeling the bar RCG magnitude RCG proper motiion + Optical depth, HST data

Sensitivity of various methods l Microlensing have a potential to find statistically significant number of Earth size planet at habitable zone. (important for TPF) Bennett, astro-ph/0404075