Takahiro Sumi STE lab., Nagoya University Study of the Galactic structure and halo dark matter by Gravitational microlensing Galactic halo Galactic center Takahiro Sumi STE lab., Nagoya University

Gravitational “Macro”lensing

Gravitational “Macro”lensing

Gravitational “Micro”lensing star arcsec. If a lens is a size of a star, elongation of images is an order of 100arcsec. Just see a star magnified lens observer distortion of space due to gravity

Plastic lens

Single lens

Application of microlensing Extra galactic　 1,halo dark matter of lens galaxy(QSO variability） Galactic 1,Galactic halo dark matter(towards the LMC ＆ SMC) 2,Galactic center structure (towards the Bulge) 3,exoplanet (towards the Bulge)

WMAP result Dark energy =0.74 Dark matter DM=0.22 Baryon 4%: Stars: 7% Neutral gas: 2% Cluster hot gas: 3% Unknown (warm gas?): 88% B=0.04

Galactic rotation curve & dark matter M~3x1011M(R<100kpc) Dark Matter Kepler: v2=GM/r

Halo Dark Matter & Paczynski’s Idea 20〜40 times more dark matter than visible mass. MAssive Compact Halo Objects (MACHOs）  WINPs MACHO can be observed by Microlensing. 〜１０−６  need to observe 1M stars！

MACHO project (1990~2000) Mt. Stromlo 1.28m telescope 12 million stars

First Microlensing event by MACHO & EROS in 1993

results toward LMC OGLE-II MACHO 5.7 yrs: 12 events M~0.5M 16% of the mass of a Standard Galactic halo. EROS 5yrs : 0 event f<25% of the halo dark matter made of MACHO with 10-7-10 M f< 10% for 3.5×10-7 -100 M OGLE-II 4 year: 3 event (1 in SMC) f<20% for 0.4M f<11% for 0.003-0.2M OGLE-II (Wyrzykowski et al.2010) Tisserand et al.2006

That is: MACHOs are not major component of Galactic halo dark matter but MACHOs exist as many as visible objects!?

Degeneracy in parameters Einstein crossing time：

Bottom line: but There are lens objects towards LMC Are they really in the halo?

Halo Dark Matter? or Self-lensing?

MEGA project results（preliminary)： 14 events f<30% Andromeda galaxy（M31） results（preliminary)： 14 events f<30% Far side

SuperMACHO 4m telescope, 1/2 nights for 3 months over 5 years. ~30events LMC Self-lensing in LMC Event rate Halo MACHO Center Outer results（preliminary）： 25events (microling+SN) Self-lensing is negligible f<30%

SuperMACHO v.s. Super Nova

MOA (since 1995) （Microlensing Observation in Astrophysics） （ New Zealand/Mt. John Observatory, Latitude： 44S, Alt: 1029m ）

New Zealand If you want to visit NZ free, join to MOA contact: sumi@stelab.nagoya-u.ac.jp If you want to visit NZ free, join to MOA contact: sumi@stelab.nagoya-u.ac.jp

MOA (until ~1500) （the world largest bird in NZ） height:3.5ｍ weight:240kg can not fly Extinct 500 years ago （Maori ate them)

MOA-II 1.8m telescope Mirror : 1.8m CCD : 80M pix. FOV : 2.2 deg.2 First light: 　　2005/3 Survey start:　2006/4

Observational targets 　　event rate: LMC,SMC : ~2 events/yr (~10-7 ) Bulge : ~500events/yr (~10-6 ) 　　Planetary event : ~10-2 ８kpc, GC  LMC 50kpc

Observation towards LMC by MOA-II ~3obs/night ~10obs/night

Difference Image Analysis (DIA) Observed subtracted

Other constraints on MACHOs Gravitational microlensing: Variability in lensed QSO EROS and MACHO (LMC) Schmidt et al ’98 Excluded (in M): 10-7 <M< 10-1 Dynamical constraint (Carr & Sakellariadou ’99) Requiring an universality of the Galaxy! open & globular clusters 103 <M<106 binary stars 100 <M<107 solar system objects 10-3<M M<10-13 halo M<10-12 disk impact on Earth

Microlensing of QSOs image A macrolens QSO image B microlenses

CDM = SULCOs 10-16<M<10-7 ? SUb-Lunar-mass Compact Objects (SULCOs) -16 -14 -12 -10 -8 -1 -2 Log(M/Ms) MACHO Log(WCO) Unconstrained g Black hole annihilation CDM = SULCOs 10-16<M<10-7 ?

Constraint on MACHOs in cosmology Current limit on compact objects in universe from lensing studies (1)microlensing of QSO Dalcanton, et al ’94 (2,4)multiple image of compact radio sources.Wilkinson et al ’01 Augusto ’01 (3)multiple gamma-ray bursts Nemiroff et al ’01 (5)multiple image of QSO Nemiroff 91

Two windows (10-13) <M<10-7 M primordial stars, BH, SUb-Lunar-mass Compact Objects （SULCO） planetesimal, PBH MAssive Stellar-mass Compact Objects (MASCO) 102 <M< 104M primordial stars, BH, PBH

Summary 1 MACHOs are not major component of Galactic halo dark matter (<20%) There are lens objects towards LMC Are they really in the halo? MOA-II is trying to solve this problem Two windows for MACHOs (SULCO, MASCO)

Galactic center

Galactic Bar de Vaucouleur,1964, gas kinematics Blitz&Spergel,1991, 2.4 IR luminosity asymmetry Weiland et al.,1994, COBE-DIRBE,confirmed the asymmetry. Nakada et al.,1991,　 distribution of IRAS bulge stars Whitelock&Catchpole, 1992, distribution of Mira Kiraga &Paczynski,1994 Microlening Optical depth θ 8kpc

COBE-DIRBE all extinction correct disk subtracted Weiland et al.,1994, confirmed the asymmetry. all extinction correct disk subtracted

Optical Gravitational Lensing Experiment (OGLE) Las Campanas Altitude: 2300m Seeing ~ 1.3” OGLE-I : 1991~1996 : 1m, 2kx2k CCD 19 events OGLE-II : 1997~2000 : 1.3m, 2kx2k CCD, 14’x14’ 500 events OGLE-III: 2001~ : 1.3m, 8kx8k mosaic CCD 600 events/yr : 35’x35’

Pieces of information Microlensing Optical depth,  and Event Timescale, tE=RE/Vt, (Sumi et al. 2006) Brightness of Red Clump Giant (RCG) and RRLyrae stars, (Stanek et al. 1997, Sumi 2004; Collinge, Sumi & Fabrycky, 2006) Proper motions of RCG, (Sumi, Eyer & Wozniak, 2003; Sumi et al. 2004), Proper motion of 5M stars, I<18 mag, ~1mas/yr

1,the Galactic Bar structure (face on, from North)  8kpc  G.C. Obs.

1,the Galactic Bar structure (face on, from North)  8kpc  G.C. Obs. 1, Microlensing Optical depth,  (Alcock et al. 2000; Afonso et al.2003; Sumi et al. 2003;Popowski et al. 2004; Hamadache et al. 2006;Sumi et al. 2006) M=1.61010M, axis ratio (1:0.3:0.2), ~20

2.Red Clump Giants Metal-rich horizontal branch stars Small intrinsic width in luminosity function (~0.2mag) =20-30, axis ratio 1:0.4:0.3 Stanek et al. 1997

RCG by IR (Babusiaux & Gilmore, 2005) Deep survery by Cambridge IR survery instrument (CIRSI) =225.5

3.Streaming motions of the bar with RCG Sumi (Princeton) , Eyer (Geneva Obs.) & Wozniak (Los Alamos), 2003 Sun Color Magnitude Diagram faint bright Vrot=~50km/s Sumi, Eyer & Wozniak, 2003

summary２ All three results are consistent with the Bar with M=1.61010M(Md=0.7x1010) axis ratio (1:0.3:0.2) =20, (Han & Gould, 1995) Vrot~50km/s 　  Little space for Dark Matter Prefer Core than cusp dark matter (Binney &　Evans 2001) MOA-II constrain stronger ρ∝r-α observation Halo+disk Halo disk

Cusp-Core problem in cold dark matter (CDM) halo Dark matter density profile at center of galaxy & galaxy cluster： Cusp: ρ∝r -1.5 or Core: ρ∝const？ Simulation: Collisionless CMD reproduces nicely the observed large scale structure of the universe (r>>1Mpc) NFW universal density profile ρ∝r-1.5 with central cusp (Navarro, Frenk& White 1997) Observation: rotation curve for CDM dominated Dwarf and low surface brightness (LSB)galaxies high surface brightness disc galaxies (Salucci 2001) have a density profile with flat central core. Log(density) Log(radius)

Density profile of Milky way (Sofue et al. 2009) disk bulge NFW(cusp) Isothermal(core) Burkert(core)

Cusp-core problem in dwarf spirals to giant low surface brightness galaxies (CDM dominated in center) rotation curve of dwarf spiral DDO47 Cusp (NFW) Core Dark halo density in ESO 116+G12 Observed simulation (NFW) Prefer core (Moore et al. 1999; de Blok et al. 2000; Salucci & Burkert 2000;Salucci&Martin 2009)

Cusp-core problem in giant elliptical galaxies; (Baryon dominated in center ) Lensing probability with image separation Δθ (Lin & Chen 2009) Lensing image in 0047-281 (Koopmans 2003) Observed galaxy subtracted Singular isothermal sphere Observation Cusp (NFW) Cusp, ρ∝r -1.9 Core Prefer cusp

Cusp-core problem in giant elliptical galaxies & galaxy cluster; (Baryon dominated in center ) Statistics of QSO multiple images (Wyithe Wyithe, Turner & , Spergel 2001; Keeton & Madau 2001; Li & Ostriker 2001; Takahashi & Chiba 2001) Arc statistics of clusters of galaxies (Bartelmann et al. 1998; Molikawa & Hattori 2001; Oguri , Taruya + Suto 2001, Oguri, Lee + Suto 2003) Time-delay statistics of QSO multiple images (Oguri, Taruya, Suto + Turner 2002) X-ray observation of galaxy cluster ⇒ generally favor a steep cusp ( α～ －1.5)

Cusp-core problem:solution Self interacting dark matter(Spergel & Steinhardt 1999 ): σ/m~1cm2/g (10-(21−24) cm2 (Mx/GeV)) make core and spherical halo(Yoshida etal. 2000) Weaker interaction doesn’t work; larger interaction leads to halo core collapse on Hubble time (e.g., Moore et al. 2000, 2002; Yoshida et al. 2002; Burkert 2000; Kochanek & White 2000)

Cusp-core problem: solution Barion-CDM interaction (BCDMIs) Dynamical friction of substructure (El-Zant et al.2001;Tonini et al., 2006;Romano-Diaz et al.2008) Stellar bar-CDM interaction (Weinberg&Katz, 2002;Holley-Beckelmann et al.2005) Baryon energy fedback(Mashchenko et al., 2006; Peirani et al. 2008) Nonsingular, trancated isothermal sphere (NTIS) Cosmological, from collapsend virialization (shapiro et al. 1999; Iliev&Shapiro, 2001) Explain core in rotation curves, but cannot explain the steep & cuspy center of massive galaxies favored by Lensing and X-ray observation (just seeing cuspy baryon?).

the Milky Way rotation curve (HI,CO,optical, VERA) Mbulge=1.8x1010M, Rbulge=0.5kpc Mdisk=7x1010M , Rdisk=3.5kpc Truncated Isothermal dark halo with h= 5.5kpc, vrot=200km/s NFW(cusp) Isothermal(core) Burkert(core) (Sufue et al. 2009)

MACHOs are not major component of Galactic halo dark matter (<20%) Summary MACHOs are not major component of Galactic halo dark matter (<20%) except two windows (SULCO, MASCO) but there are lens objects towards LMC, important for astrophysical point of view dark matter density profile in the galaxy may be core rather than cusp microlensing contribute to constrain

(Total event) ~103 for 10-8Ms, DT~103sec Microlensing by SULCOs in Galactic halo M33 DM33 = 790kpc DLMC = 50kpc で Small source size 8*10-9 (star radius /106 km) arcsec (Total event) ~103 for 10-8Ms, DT~103sec 　　　　　　　~1 for 10-11Ms , DT~1sec For 80hours obs. by SUBARU/Suprime-cam

A B C D MASCOs M=103 if WMASCO=Wm 2.5mas N=1.7(M/104)-1 mas-2 Inoue & Chiba ApJ ’03

Distribution of surface brightness resolution＝0.025mas