Dr. Léon Koopmans (Kapteyn Institute) Prof. Mike Garrett (ASTRON) Dr. Olaf Wucknitz ( AIfA Bonn) OZ Lens 2008, Sydney (Australia) OZ Lens 2008, Sydney (Australia) Alicia Berciano Alba (Kapteyn Institute)

Optical/UV light IR/submm dust re-radiated light ~ 50% of the total radiation in the universe Critically important to understand galaxy formation and evolution dust obscured galaxies Starburst galaxy SED dust re-radiated

 SMGs = dusty, FIR luminous starburst galaxies at high redshift  Discovered with SCUBA (JCMT) at 850  m (Smail, Ivison & Blain 1997) Bright SMGs (what we can see) Faint SMGs (the unknown territories) 2 mJy SCUBA’s confussion limit at 850  m Properties of bright SMGs: Median redshift ~ 2.3 L FIR > L sun  ULIRGs SFR ~10 3 M sun /yr Gas-rich mergers Dust temperature ~ 35K M gas ~ – M sun Bulk of the submm background energy at 850  m (Knudsen, van der Werf & Kneib 2007)

Multiply imaged Singly imaged ~ 16 (Cowie et al 2002, Knudsen et al. 2007) MS0451 (Borys et al. 2004; Berciano-Alba et al 2007) A2218 (Kneib et al. 2004/5; Garrett et al. 2005) A1689 (Knudsen et al. 2007)

Mosaic ~ 13 arcmin radius (Moran et al. 2007) Cluster’s core ~ 3.5 arcmin z = 0.55

Data: Optical : HST F702W, F775W, F850LP NIR (circles) : CFHT JHK’- band Submm (contours): SCUBA 850  m Source plane ERO B ERO C ~ 10 Kpc Image plane Redshifts: LBG ARC1 : z = (VLT spectroscopy) EROs* B,C : z = 2.85 (lens model) * Extremely Red Objects MERGER!!!

FIR Submm dust re-processed UV radiation from massive stars synchrotron emmision from electrons generated by SN Radio FIR (submm) Massive star formation Radio interferometry High resolution “version” of the submm map High-z starburst: Observed in submm = emitted in FIR

 B-array (Berciano Alba et al. 2007) 2 x 4 hours (9th and 10th June 2002) Project ID AN109, PI: Nakanishi Resolution: 6.34” x 4.87” pa= 7.73  A-array 2 x 6 hours (5th and 10th Feb 2006) Resolution: 2.07” x 1.58” pa= Data reduction: AIPS + ParselTongue

 Red box Cluster’s center ()  Black circle primary beam (~15’ radius)  Black box HST mosaic (~13‘ radius)  Blue boxes radio fields (~30‘ radius)

 Red box Cluster’s center ()  Black circle primary beam (~15’ radius)  Black box HST mosaic (~13‘ radius)  Blue boxes radio fields (~45‘ radius)

Resolution = 2.78 x 2.18 arcsecs pa=-0.21 rms noise =  Jy/beam Grey scale: 2 x noise Contours: 4, 5, 6, 8 and 10 x noise

Resolution = 2.78 x 2.18 arcsecs pa=-0.21 rms noise =  Jy/beam Grey scale: 3 x noise Contours: 4, 5, 6, 8 and 10 x noise CR1 CR2

4 detections: RJ, E1, E2, E3 2 tentative detections: C1, C2 SNR ~ 6 SNR ~ 4.5 SNR ~ 4.6 SNR ~ 6 SNR ~ 11 SNR ~ 5 (flux ~ 34  Jy) (flux ~ 23  Jy) (flux ~ 28  Jy) (flux ~ 42  Jy) (flux ~ 170  Jy) (flux ~ 52  Jy) CR1 CR2

Alignment Radio and NIR map aligned respect to the HST map  Radio: 13 sources, rms distance = 0.29”  NIR: 93 sources, rms distance = 0.06” Data  Optical: HST ACS F814W ( Moran et al 2007 )  NIR: Subaru CISCO K’-band ( Takata et al 2003 ) Positional Errors  Radio: FWHM / (2*SNR)  between 0.1” and 0.3”  NIR: 0.2” (fitting error for the standard stars used for the astrometry)

White contours: 20cm radio emission Blue squares: NIR sources ERO’s photo-z: (Takata et al. 2003) T B = T c = T d = 0.5 T f = 1.26

White contours: 20cm radio emission Blue squares: NIR sources Yellow squares: optical arcs produced by a LBG

z photo = 0.45 Source plane ERO B ERO C ~ 10 Kpc MERGER!!!

 Extended source: ~ 3 beams (~ 6”)  Peak not consistent with any optical counterpart  mayor axis aligned with a posible cluster member z photo = 0.4 AGN + radio jet Not associated with the lensed submm emission!!!

Radio contours = 3,4,5,6 and 7 x 30  Jy/beam

 The brightest radio detection (RJ) is not related with the lensed submm emission (probably an AGN jet)  The other radio detections (E1,E2,E3,CR1,CR2) are counterparts of the submm emission  2 radio detections (E1,E2) confirm that ERO B is associated with the submm emission  2 tentative radio detections (CR1,CR2) support the merger hypothesis

 The coming years will see a revolution in radio / mm interferometric observations: EVLA, eMERLIN, ALMA, SKA, LOFAR…  Window to study high redshift dust obscured universe unnaccesible in optical  Time to think about robust multiwavelenght source reconstruction