objects via gravitational microlensing

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12 EROS : A search for dim galactic 11 objects via gravitational microlensing 10 9 8 7 6

1 12 EROS : A search for dim galactic 11 objects via gravitational microlensing James Rich : CEA Saclay/DAPNIA Service de Physique des Particules 5 4 J. Rich, Nov 8, 2007 p.1/37

2 * ' % (., 7 4, ; ( ', :, = 5 ( E * D * * #! * J J I H 3 ' < K J! ( H < - K.J, : I / K <. ( : ; % *: >( * / < KK ( : I ' 5 ; * AC ; * : Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds Astronomy and Astrophysics, 469 (2007) ) ( & & "$#! 2 10 & / + - " + ( +! 8 * / < / 5 "# ( 5 & 5 % ( 9 "# A = 5 5 >. 5 ' G? F' C D % ( > 5? C : 5! /! B! >/ AC? / + / B;?? +? ' C / "$# # + / E A +? C " " " // I + / +? % L ; & * ' ( H + < E 5 +? D / 5 A < KK 38? K D 5 H * & C M K A6<( 0 ' M ; C A* 0' 0 3: 2 + +?, * ' " "? A - J % C KKJ # ' A C. # J. Rich, Nov 8, 2007 p.2/37

3 R Q PO N Dark Matter in the Milky Way Milky Way Galactic Bulge LMC Dark Matter Halo particles or objects 50 kpc 8 kpc Earth Dark matter particles (wimps) can be detected as they pass through the Earth. Neutrinos or photons from wimp annihilation can be detected Dark objects (MACHOs) in the halo can lens visible stars in the LMC (Large Magellanic Cloud). Probability per star. J. Rich, Nov 8, 2007 p.3/37

4 S W N W Y S Z MACHOS MACHOS = MAssive Compact Halo Objects Candidates : brown dwarfs ( old white dwarfs ( primordial black holes ( V P PUT X PUT ), ), ) Detection by microlensing (Paczyński,1985) Projects : EROS : MACHO : between 10% and 50% of the halo is made of machos OGLE : MOA : Supermacho : J. Rich, Nov 8, 2007 p.4/37

5 \ ] \ \ \ ] S \ ] S S \ ] S Macho Halo fraction Magellanic Clouds : M31 : MACHO (Alcock et al 2000) : with [P PUT P^ PUT EROS (Afonso et al, O ^ PUT EROS (this [P PUT \ W O ^`_ P T W X _ P T W X _ P T W a _ PUT AGAPE (Calchi Novati et al a ^ PUT \ ] \ b PUT MEGA (de Jong et al Pc PUT W X _ P T W X _ PUT J. Rich, Nov 8, 2007 p.5/37

6 d r q z yxw qu ˆ N tr Ž X c O T A Gravitation Microlensing Event star star small image dark object and Einstein ring large image telescope telescope ikj9l h f S dgf e time scale summed flux vs. 5 n ƒ z {} ~ y yxw stvu npo m z {} ~ y ŠŒ d f Amplification œ š ŽŽ Ž idgf d 3 if undeflected line-of-sight inside Einstein Ring. Ÿž J. Rich, Nov 8, 2007 p.6/37

7 A lensed star in the Milky Way b P PUT reconstructed stars event , b=-3.8 before during log(flux) t (days) J. Rich, Nov 8, 2007 p.7/37

8 O \ X c O T S R Q PO N ] Q PO O N S Q PO N Galactic Bulge and Magellanic Clouds optical depth =probability for Ÿž k : h f «ª Œ Galactic Bulge 8 kpc Earth Milky Way 50 kpc Macho Halo LMC SMC Galactic Bulge lenses = normal faint stars b Magellanic Clouds lenses = hypothetical machos for for faint Galactic and Magellanic stars ^ b PUT J. Rich, Nov 8, 2007 p.8/37

..) Marly 1m telescope, ESO LaSilla 2 ccd cameras ( b ) 2 mosaics of 8

9 O EROS-2 Expérience de Recherche d Objets Sombres (CEA-Saclay, LAL-Orsay, IAParis, Obs.Marseille...) Marly 1m telescope, ESO LaSilla 2 ccd cameras ( b ) 2 mosaics of 8 CCDs, 2048 Data taking : terabytes of data 2048 pixels 2 filtres rouge et bleu J. Rich, Nov 8, 2007 p.9/37

10 µ R PO ^ T EROS-2 : Milky-Way fields 66 Galactic Bulge fields : G X PO P P S dÿ³ R PO ^P ±`² X ± Bulge clump giants ^ J. Rich, Nov 8, 2007 p.10/37

11 ¹¹¹ ¹¹ ºººº»»»» ººººº»»»»»» ºººººººººº»»»»»»»»» ºººººººººº»»»»»»»»»» ººººººººººººº»»»»»»»»»»»»» ººººººººººººº»»»»»»»»»»»»» ººººººººººº»»»»»»»»»»» ºººººº»»»»»» ºººº»»»» ºº»»» ººººº»»»» EROS and MACHO LMC fields EROS LMC Fields ¹ ¹ r.a (hr) dec. (deg) MACHO LMC Fields 11million stars in dense fields EROS LMC Fields 6million bright stars in sparse fields (good efficiency and photometry) J. Rich, Nov 8, 2007 p.11/37

12 Z Typical color-magnitude diagrams Bulge 16 LMC R eros clump giants R eros bright stars (B R) eros (B R) eros 1.5 Use of Bulge clump giants + LMC bright stars reliable optical depth J. Rich, Nov 8, 2007 p.12/37

13 ¼ A light curve (Galactic Bulge) EROS-2 : July, 1996 February, R u te t u te t B u te t J. Rich, Nov 8, 2007 p.13/37

14 A parallax event 10.5 observer lens I (EROS) 11 no parallax fit parallax fit Sun source residual HJD J. Rich, Nov 8, 2007 p.14/37

15 A binary lens u te t J. Rich, Nov 8, 2007 p.15/37

16 Z S ½ W V ^ P ¾PUT ± O b P T N N ½ PLANET collaboration lightcurve of EROS b ± PUT c ^ P T J. Rich, Nov 8, 2007 p.16/37

17 A binary source u te t J. Rich, Nov 8, 2007 p.17/37

18 A Strong Blend R u te t bf 0.06 u te 8.57 t A dim star in the seeing disk of a clump giant R u te t Blend fit: bf 0.08 te=85 days No blend fit: te=9 days J. Rich, Nov 8, 2007 p.18/37

19 Contribution to calculated optical depth 120 EROS-2 events on Bulge clump giants Simple Events : 79% Strong Blends : 3% Parallax : 11% Caustic events : 5% Non-caustic : 2% J. Rich, Nov 8, 2007 p.19/37

20 i S b X Impact parameter distribution [minimum distance (lens)-(line-of-sight)] distribution should be flat h f >= 1 bump Nevents S Â À Á } bump achromatic scan 0.00 u final u0 distribution is ~flat J. Rich, Nov 8, 2007 p.20/37

21 c ¾ b [ O Pb \ \ ± O c T Time-scale distribution 20 entries 120 mean r.m.s S Ä Ãdgf days N events d f (80% of ) N events Log t E (days) entries 115 mean r.m.s Cumulative optical depth Log t E (days) Log t E (days) J. Rich, Nov 8, 2007 p.21/37

22 ± b O Å T ½ Q ³ S EROS-2 Optical Depth to Galactic Bulge 6 6 optical depth / EROS 2 fit C B A latitude (deg) EROS 2 Hamadache et al, A&A (2006) S Æ ½ Ð Ïc Í Ë ÍÎ ³ ÊÌË É È Ç b c ¾PUT O ± ¾P T X c PUT Agreement with Galactic models : Han and Gould Bissantz and Gerhard Evans and Belokurov optical depth / C B A longitude (deg) J. Rich, Nov 8, 2007 p.22/37

23 Optical Depth to Galactic Bulge optical depth vs Galactic latitude optical depth / EROS 2 MACHO OGLE 2 general agreement EROS/MACHO/OGLE b (degree) 5 J. Rich, Nov 8, 2007 p.23/37

24 The only EROS Magellanic candidate (Bright source sample) sm0054m 17.2 R 5761 EROS2 SMC 1 R u te t B B u te t eros R R B (B R) JD eros Lens probably in SMC (expected d f, optical depth) J. Rich, Nov 8, 2007 p.24/37

25 Ñ ß â Ô b N S Ø Ô l ÖÂ Ô ÜÞ l o åæ ^ ± X b N T T S S Ò) Number of expected events ( à Ôá ßà Ó l ÜÁ ÛÝÜ ÚÙ i ª O ] ÓÕÔ äã R PO b P^ P ^ Q PO ^ ²³ i ª Ü Ø æ Á â (LMC) (SMC) (EROS-1) c ^ events expected X a V V 1 Efficiency vs log(te/day) J. Rich, Nov 8, 2007 p.25/37

26 \ ] N W Z T TT TT EROS Limits on Macho Halo fraction EROS 1+EROS 2 EROS 2 LMC Number of events expected for 100% macho halo N events 50 EROS 1 Plates EROS 2 SMC No LMC events seen (Tisserand et al 2007) macho Halo fraction EROS 1 CCD EROS 2 + EROS 1 upper limit (95% cl) log(m/msun) MACHO f=0.2 M=0.4Msun log(m/msun) EROS Limit on macho halo fraction : for [P P T X PUT Events reported by MACHO collaboration likely due to ordinary stars in the LMC J. Rich, Nov 8, 2007 p.26/37

27 Z The 17 Macho events in EROS data 13 events before start of EROS-2 (July 1996) MACHO LMC-23 : before EROS-2 and then repeated 7 years later in EROS-2 : variable star. MACHO LMC-14 : event seen but not in bright sample MACHO LMC-15 : source star dimmer than EROS limit MACHO LMC-20 (B candidate) : event seen but not in bright sample J. Rich, Nov 8, 2007 p.27/37

28 J. Rich, Nov 8, 2007 p.28/37

29 MACHO color-magnitude diagram Only Macho-LMC-25 would be in EROS Bright Sample J. Rich, Nov 8, 2007 p.29/37

30 A MACDO event J. Rich, Nov 8, 2007 p.30/37

31 A MACDO event J. Rich, Nov 8, 2007 p.31/37

32 ½ PO \ Q PO \ W W ² ³ O PO MACHOs ruled out 1 limit on halo fraction EROS MACHO Combined disk stability globular cluster abundance 0 LMC events (bright sample) 0 LMC events with (full sample, preliminary) ž dgf EROS wide binary abundance log(m/msun) 8 J. Rich, Nov 8, 2007 p.32/37

POINT-AGAPE : M31 410 400 400 350 0 200 400 600 800 PA-99-N1 r light curve 0 200 400 600 800 PA-99-N2 r light curve 410 400 400 350 0 20 40 PA-99-N1 r light curve (zoom) 0 50 100 PA-99-N2 r light

33 POINT-AGAPE : M PA-99-N1 r light curve PA-99-N2 r light curve PA-99-N1 r light curve (zoom) PA-99-N2 r light curve (zoom) N2 N1 N PA-99-N1 g light curve (zoom) PA-99-N2 g light curve (zoom) S7 S4 S3 * S PA-00-S3 r light curve PA-00-S3 r light curve (zoom) PA-00-S4 r light curve PA-00-S4 r light curve (zoom) PA-00-S3 i light curve (zoom) PA-00-S4 i light curve (zoom) J. Rich, Nov 8, 2007 p.33/37

34 POINT-AGAPE : M31 dn/d(t 1/2 ) t 1/2 (days) J. Rich, Nov 8, 2007 p.34/37

35 Z \ ] Conclusions Galactic Bulge events well described by Models Little room for CDM cusp? MACHOs not dominant component of Milly Way Halo (EROS-2) [P PUT LMC events seen by MACHO collaboration may be due to dim stars in or near LMC bar Unexplained microlensing-like events in M31 Microlensing surveys are a goldmine of variable astrophysical phenomena J. Rich, Nov 8, 2007 p.35/37

36 R-Coronae Borealis Stars Tisserand et al A& A (2004) J. Rich, Nov 8, 2007 p.36/37

37 Rings around SN1987a Film : http ://eros.in2p3.fr/echoessn1987a/ Difference between 2 images J. Rich, Nov 8, 2007 p.37/37

Review of results from the EROS microlensing search for massive compact objects

Author manuscript, published in "IDM008 - identification of dark matter 008, Stockholm : Sweden (008)" Review of results from the EROS microlensing search for massive compact objects Laboratoire de l Accélérateur