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Strongly lensed high redshift galaxies identified in Herschel wide surveys

Strongly lensed high redshift galaxies identified in Herschel wide surveys Prospects for ALMA observations Alain Omont (IAP, CNRS and Université Paris 6) On behalf of the H-ATLAS and HerMES Teams and the IRAM Team.

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Strongly lensed high redshift galaxies identified in Herschel wide surveys

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  1. Strongly lensed high redshift galaxies identified in Herschel wide surveys Prospects for ALMA observations Alain Omont (IAP, CNRS and Université Paris 6) On behalf of the H-ATLAS and HerMES Teams and the IRAM Team

  2. Strongly lensed high redshift galaxies identified in Herschel wide surveys • Prospects for ALMA observations • Using gravitational magnification • for studying Ultra-Luminous InfraRed Galaxies (ULIRGs) at high redshift • Introduction • - (Local ULIRGs) • - High-z ULIRGs and the magic of the submm window • - Mm/submm continuum & line studies of high-z ULIRGs: the promise of ALMA • - Herschel wide surveys multiply by 100 the number of high-z ULIRGs identified • - Herschel lenses increase the sensitivity by ~10 for studying high-z ULIRGs • Herschel high-z stronglenses • - Earlystudies of Herschel lenses • - Prospects and Currentstatus • Example: H2O mm/submmlinesathigh z in Herschel lensed galaxies • Examples of ALMA programs possible with Herschel high-z lensed galaxies

  3.  Arp 220: prototype of ULIRGs • LIR = 1.4×1012 Lo • thought to be in the final stage of merging • radio & NIR imaging double nucleiprojectedseparation ~300 pc • MH2 ~ 1010Mo within central kpc • in accord with simulations of galaxymergers • M 82: prototype of LIRGs, • 3.2 1011 Lo • Strongmid-IR PAH emission, even in strongoutflow • Most high-z ULIRGsseem to have IR SEDssimilar to M 82 • Arp 220 M 82

  4. ULIRGs observed with the WFPC2 of the HST at optical wavelengths. Many of these ULIRGs are merging galaxies See Steve Lord’ s talk

  5. SMGs: strongest starbursts in the Universe Important players of star formation at z >~ 2 • ULIRGs are much more numerousathighredshiftthanlocally • factor close to 1000at z=2 • Revealed by SCUBAsurveysat 850µm • (+ MAMBO at 1.2mm  AzTEC,LABOCA, BOLOCAM) •  « Sub-Millimeter Galaxies » (SMG) • Easydetection of dust FIR emissionthrough « inverse K-correction », sameflux observedatl ~ 1mmfrom z ~ 0.5 to 10

  6. Dust detection: The Magic of the high-z submm window FIR emission of cold dust (Td ~ 30-40 K) : - steepsubmmspectrum - compensates for distance - Snpracticallyindependent ofz from z ~ 0.5 to 10 Effectoftenknown as « negative K correction » SPIRE Redshift degeneracy from Bertoldi, Voss, Walter LFIR(Lo) = 4x1012 S1.2mm(mJy)

  7. ULIRGs and Star Formation athigh-z • ULIRGsdominate star formation at z>~2 • SMGs (and Herschel/SPIRE) sources are luminousULIRGs • Theyprovideonly a small fraction of total star formation Lindner+ 2011 Le Floch+ 2005 > ULIRGs> z=2 SMGs SPIRE sources Total Spirals LIRGs ULIRGs 1.2mm

  8. SMGs: strongest starbursts in the Universe Important players of star formation at z >~ 2 • Revealed by SCUBA surveysat 850µm (+ MAMBO at 1.2mm  AzTEC, LABOCA, BOLOCAM) Easydetection of dust FIR emissionthrough « inverse K-correction », same flux at ~1mmfrom z ~ 0.5 to 10 • Giantstarburstsat the peak of elliptical formation z ~ 2-3  1-4 • A few 1012Lo: at least ULIRGs ~1 per 3-5 arcmin2 • Most exceptionalHLIRGs1013Lo  ~1 per 50-100 arcmin2 • nothingequivalent in the local Universe • probably in most massive DM halos • progenitors of BCG/cD galaxies of clusters? • Only ~1000 SMGsprovided by SCUBA/MAMBOASTEC/BOLOCAM surveys • ( <~ 1-2 deg2) •  Herschel surveys are detectingseveral 105SMGs

  9. Mm/submmstudies of high-z ULIRGs - High extinction makesoptical/NIR studies of high-z ULIRGshardlyfeasible - Extinction ispracticallynegligible in mm IRAM-PdBI • In addition to continuum, molecular mm linesare keytool for high-z ULIRG studies • CO lines are the strongest and most important (but C+): • Theygive the mass of moleculargas MH2 • (Rotation) velocity profile • Spatial extension of moleculargas dynamical mass • Rotation line ladder (SLED)  TK + nH2  multi-TKgas •  AGN excitation of high-J lines • HCN is the best tracer of dense gas and star formation • H2O traces warm, dense gas and verystrong IR • C+ (verystrong, veryhighfreq.) traces diffuse, (partially) ionizedgas

  10. IRAM-PdBI ALMA • In addition to continuum, molecular mm linesare keytool for high-z ULIRG studies • CO lines are the strongest and most important (but C+): • Theygive the mass of moleculargas MH2 • (Rotation) velocity profile • Spatial extension of moleculargas dynamical mass • Rotation line ladder (SLED)  TK + nH2  multi-TKgas •  AGN excitation of high-J lines • HCN is the best tracer of dense gas and star formation • H2O traces warm, dense gas and verystrong IR • C+ (verystrong, veryhighfreq.) traces diffuse, (partially) ionizedgas

  11. PdBI CO high-resolution study of SMGS Tacconi et al. 2008 Compact post-merger Resolved pre-merger

  12. HERSCHEL • See Steve Lord’ s talk • SpaceObservatory, ESA (+NASA) • 3.5m dish • 3 instruments: • 5 • Camera-photometer, FTS • SPIRE 250-500µm widesurveys 1000 deg2 • ~4 x 105high-z ULIRGs • - PACS 70-160µm • Heterodyne • HIFI • May 2009  January-March 2013

  13. Herschel high-z extragalacticwidesurveys • H-ATLAS 550 deg2 • HerMES 70 deg2deeper + 270 deg2shallow • Bothmostly SPIRE (250, 350, 500µm) close to confusion limit • Plus • PACS surveys: smaller areas, deeper • HLS: lensing clusters, • 100 deg2overlapwith SPT (South Pole Telescope) • AKARI/NEP ? • etc.

  14. H-ATLAS PIs Eales & Dunne 550deg2

  15. The HerMES survey SPIRE Guaranteed Time; PIs Seb Oliver & Jamie Bock • ~900h (Multi-levelDeepfields ~5 deg2 ) • Wide fields • ~70 deg2Practically all Spitzerwidefields: • SWIRE (Lockman, ELAIS-N1, ELAIS-N2, XMM-LSS, CFDS, ELAIS-S1) • + FLS, Bootes, AKARI-ADFS • practically all observed • mostly SPIRE (250, 350, 500µm) • practicallyat the confusion limit • somewhatdeeperthan H-ATLAS • multi-lancillary data •  + HeLMS 270 deg2 • shallow, equatorial, RA ~ 0

  16. without optical IDs with optical IDs Herschel surveysrevolutionize the field of high-z submm galaxies Several 105s high-z sources Half H-ATLAS sources have z>1 (inverse K-correction) All high-z sources are ULIRGs with SFR > 300 Mo/yr and LFIR > 1012Lo Some Herschel/SPIRE sources are warmer thanSMGs and not detectedat ~1mm Some cold SMGs not detected by Herschel Lapi et al. 2011 Lapi et al. 2011

  17. Herschel lenses increase the sensitivity by ~10 for studying high-z ULIRGs The power of gravitational lensing Since 20 years lenses mark the frontier of mm radioastronomy

  18. « Einstein Cross » Einstein ring QSO (radiogalaxy) Cloverleaf QSO X-Ray optical Gravitationallensing

  19. Unlensed SMGS Neri+ 2003 The power of gravitational lensing Thanks to magnification factor µ ~11 - CO lines are more intense by ~10 than in unlensed SMGs - High S/N HCN & HCO+ lines are detected while they are out of reach in unlensed SMGs with current PdBI sensitivity Lensed Cloverleaf

  20. APM08279+5255 Cloverleaf The power of gravitational lensing Since 20 years lenses mark the frontier of mm radioastronomy Rowan-Robinson’s galaxy FIRAS10214 Swinbank’s Eyelash SMMJ2135

  21. Herschel lenses increase the sensitivity by ~10 for studying high-z ULIRGs Herschel high-z strong lenses Early studies of Herschel lenses Prospects and Current status

  22. Submmwidesurveys are ideal for findinghigh-z lenses • High-z submm sources • are verystrong • (‘inverse K-correction’) • - Verysteepunlensedcounts • Almosthalf of the strongest • SPIRE sources are high-z • lenses • Veryeasy to identify • from local galaxies • (+ blazars) Local galaxies radio lensed unlensed Negrello et al. 2010

  23. Earlystudies of Herschel high-z stronglenses • H-ATLAS SDP Field Negrello et al. Science 2010 • ~14.4 deg2 7000 sources • Brightest 500µm sources: • 11 sources with S500μm > 100 mJy • 4 nearby galaxies (z<0.05), • + 1 blazar, 1 galactic blob •  5 high z candidates • confirmedredshifts z = 1.5 – 3.4 (faint)

  24. SED of lens candidates in H-ATLAS S DP field clear cases of double-source SEDs z~0.2-0.8 elliptical galaxy + high-z ULIRG Negrello+2010

  25. Submm photometric redshifts Ratios S250/S350 & S350/S500 plus a template such as Arp220  submm z-phot Good agreement with zCO for 6 sources with zCO A good value of z-phot is important for searching zCO with a limited bandwidth Adding 1.2mm MAMBO flux helps: S1.2mm=10-40mJy Dannerbauer+ Measuring zCO at z>~4 is difficult with Zspec, impossible with Zpectrometer  PdBI, EMIR or CARMA blind search e.g. ID15.141 ID15.141

  26. Zspec Lupu et al. to be submitted to ApJ Redshifts have been confirmed with PdBI or CARMA interferometers

  27. Best, highest-z H-ATLAS SDP lenses Sub-Millimeter Array images at 870µm Extended images: gravitational arcs on top of the lens galaxy Red 870µm contours on top of I Keck image

  28. Extended images: gravitational arcs on top of the lens galaxy Idealized gravitational arcs from Negrello ESLAB2010

  29. S. Serjeant

  30. Earlystudies of Herschel high-z stronglenses • H-ATLAS prominent z=4 lens ID15.141 • Cox et al. 2011 (faint)

  31. Z = 4.24

  32. Early studies of Herschel high-z strong lenses 3. HerMES SDP exceptional lens HerMES Lockman-01 = HLSW-01 Very wide image Riechers et al. 2011 PdBI, SMA & CARMA maps K. Scott et al. 2011 Z-Spec spectroscopy Gavazzi et al. 2011 lensing modeling (faint)

  33. HerMES Lockman-01 = HLSW-01 PdBI + SMA Riechers+ 2011

  34. Prospects • for studies of Herschel high-z stronglenses • A simple extrapolation of 5 lenses in 15 deg2 H-ATLAS SDP yields • ~200-300 similarlenses in total in ~1000 deg2 Herschel surveys • This numbermaybemuchincreased by lowering the flux limits, e.g. by a factor >~5 for S(350µm) > 80 mJy • Workis in progress for extensions of lens identifications: • - larger areas • - lower flux limits • - use of additional data, e.g. NIR surveys for identifying the deflectors • One maythusexpectthousandsof Herschel high z lenses, • including~50-100 lensed sources in which the magnification is > 10

  35. Prospects for studies of Herschel high-z stronglenses The two main applications of Herschel lensesshouldbe: 1. Deepstudies of high-z lensed sources (seebelowe.g. for H2O, ALMA ) 2. Studying the evolution of darkmatter halo of the deflectors - Most deflectors are massive spheroidswith a few spirals and groups - Redshifts of the deflectors are foundmostlybetween z = 0.2 and 1, with a significant fraction at z>1. This ismuchhigherthan for the deflectors of opticallenses - A major goal isthus to check the evolution of dark-matter halos at z~ 1 In addition Herschel wide surveys are important tools for cosmological studies, through map fluctuation studies, etc. (see e.g. Cooray+ 2010)

  36. Work in progress on Herschel high-z stronglenses • Enormousamount of work • for identifying and following up hundreds of Herschel lenses • 2/3 of observations carried on; half of themwellprocessed • Severalhundreds: identified candidates • planned HST snapshots • Severaltens: 1mm observations  PdBInext Winter • CO redshifts PdBInext Winter • Identifications of deflector candidate with z-phot • About 10: High-resolution mm/submm images  PdBInext Winter • High-resolutionoptical/NIR (HST, Keck-AO…) • Spectroscopicredshifts of deflector • Lens models • About 5: Otherlinesthan CO (and CI): H2O, C+ PdBInext Winter • Multi-line CO SLED  IRAM-30m next Winter

  37. H2O mm/submmlinesathigh z - Strong H2O emission in the nuclei of local ULIRGs - H2O in high-z lensedQSOs - H2O in Herschel lenses - Prospects H2O is one of the mostabundantmolecules in the ISM - In cold cloudspractically all in ice on grains abundance up to ~10-4, 1/3 of total oxygen - Desorbedinto the gas in hot cores No confirmeddetection of H2O athigh z prior to 2011

  38. H2O in local ULIRGs (Mrk 231) H2O is one of the mostabundantmolecules in the ISM - In cold cloudspractically all in ice on grains abundance up to ~10-4, 1/3 of total oxygen - Desorbedinto the gas in hot cores But itisverydifficult to observe in the gas: - Needs to bedesorbedfrom the grains - Atlow z: H2O lines are completelyabsorbed by water in the Earthatmosphere space - Athigh z: H2O lines are veryweakwithoutlensing amplification No confirmeddetection of H2O athigh z prior to 2011

  39. Strong H2O emission in the nuclei of local ULIRGs • Compact single- double-nuclei (+AGN) of major mergers • seetalks by D. Sanders and others • Prominent FIR H2O absorption lines in local ULIRGs (+AGN) such as Arp220 , Mrk231… (ISO; Herschel Gonzalez-Alfonso +2011) • Evidence for high H2O abundancefrom H218O , and high18O/16O ratio • (Gonzalez-Alfonso+2011, Martin+2011) • Herschel/SPIRE: spectacularsubmmemissionlines • e.g. Mrk231(obscured QSO) (van der Werf+ 2010) • SeveralH2O lines up to Eexc~600K • Stronglines comparable to CO (verydifferentfromM82 and PDR) • - Plus high-J CO (strong), [CI], H2O+, OH+, HF, CH+, [NII], etc.

  40. GHz Van der Werf et al. 2010

  41. SPIRE van der Werf+ 2010 CO J 15 14 13 12 11 10 9 8 7 Gonzalez-Alfonso+ 2010

  42. Strong H2O emission in the nuclei of Mrk 231 • Prominent FIR H2O absorption lines in local ULIRGs (+AGN):Arp220, Mrk231 • Evidence for high H2O abundancefrom H218O , and high18O/16O ratio • Herschel /SPIRE: spectacularsubmmemissionlines • e.g. Mrk231(van der Werf+ 2010) • - Several H2O lines up to Eexc~500K, • - Stronglines comparable to CO (verydifferentfrom M82) • - Plus high-J CO, [CI], H2O+, OH+, HF, CH+, [NII], etc. • Implications (Gonzalez-Alfonso+ 2010): • - Lowerlevelsmaybeexcited by warm dense gas (~100K, ~106cm-3), • withhigh H2O abundance (>~10-6) • - Higherlevelsimply intense FIR excitation in few 100s pc • - Possible role of shocks, AGN (XDR), CR excitation, but unclear • High z: Manyobjectssimilar to MrK231 are expected, • but very few detections of H2O are reported up to now •  Herschel lenses

  43. H2O lines must beeasilydetectable in many Herschel lenses • Herschel SPIRE 250/350/500 µm • surveys (~1000deg2) are ideal to find • rare, high-z stronglylensedSMGs • Negrello+2010 • Only 1-2 deg2 observed by ‘traditional’ • SCUBA/MAMBO/ASTEC surveys •  practically no stronglens • Breakthrough by Herschel surveys • hundreds of stronghigh-z lenses • (whileonly ~6 foundbefore Herschel) • Unique opportunity for deepstudies • of high-z mm/submmlines • As performedwithclassical mm • lenses, e.g. the Cloverleaf • H2O line intensities are a significant • fraction of thatof CO lines in Mrk 231. • Theyshouldbeeasilydetectable in • stronglylensedsimilarhigh-z ULIRGs Negrello+ 2010

  44. PdBI detection of H2O in H-ATLAS SPD-17b z = 2.305 ZSpec H2O tentative detection Lupu et al. 2011 H-ATLAS SPD-17 identified as lensed ULIRG by Negrello+ 2010 Complex HST image (Negrello+ in prep.) Richspectrum: high-J CO z=2.308  Lapp~4 1013Lo Possible H2O 202-111at 299GHz: seemsverystrong but noisy (2.6s)

  45. PdBIdetectionof SPD-17b at299GHz z=2.3 • Omont et al. 2011 A&A 530, L3 GHz km/s Compact D-conf. Continuum 32+/-2 mJy (+ extended A,B Confs. not yetfullyprocessed)

  46. Detection of H2O in H-ATLAS G12-29 z= 3.3 One of the strongest Herschel lensed sources: S500µm = 285 mJy, even detected by Planck • Z-Spec/APEX spectrum (Lupu+ in prep.) • impressive high-J CO lines up J=10-9 (11-10?) • z~3.254 • Confirmed with Zpectrometer 3.2588±0.0012 • Strong line at 273.3GHz H2O 321-312 • needed to beconfirmed • 273 GHz is not currently observable withPdBI, • but anotherstrong H2O line isexpectedat • 231.96 GHz (in a badZSpecchannel) • (H2O isalsotentativelydetectedat257.7GHz) • PdBIDetectionof H2O 202-111 • Preliminaryresults (R. Neri) • C-conf., 6 antennas • Veryrobustdetection • I ~ 5 +/-0.55 Jy.km/s • ~ I(SPD.17b) / 2  ~sameluminosity • 231.96 GHz  z = 3.260 • Width 680 km/s

  47. Lensed images of G12-29 Multi-galaxy deflector The K image is very different from ~1mm images Keck K-band SMA 870µm PdBI 1.3mm continuum + H2O

  48. 5otherdetectionsof H2O in high-z sources • (at IRAM 2011, exceptCloverleaf) • Multi-line detection in the lensed QSO APM08279+5255 z = 3.9 • van der Werf et al. 2011, plus Lis et al. 2011, Bradford et al. 2011 • Zspec tentative detectionin the lensed QSO Cloverleaf z= 2.56 • Bradford et al. 2009 • Plus recentdetections of twoother Herschel sources and one QSO

  49. Inferred conclusions for H2O in high-z ULIRGs The detection of H2O implies special excitation conditions in an intense IR field and a warm dense gas, similar to Mrk 231 with higher luminosity The high H2O/CO ratio makes it unlikely that the H2O emission originates in classical PDRs But all the evidence suggests that SDP.17b, G12-29 and Mrk 231 have similar properties, with warm, dense gas and strong IR field ( plus possibly shocks, XDR, CR). However, this needs to be confirmed by higher excitation lines of H2O  ALMA

  50. Prospects for H2O studies in Herschel lenses (with ALMA) • (Full) ALMA willeasilydetect H2O multi-lines in hundreds of Herschel • high-z lenses(filler in ALMA Cycle 0 for 3 sources, and search for H2O in 8 • additional H-ATLAS lensesisscheduledat 18 PdBInext Winter) • Togetherwithhigh-J CO lines, H2O lineswillproviderich information • about the conditions in the dense warm ISM of the compact mergernuclei • of SMGs, and theirstrong FIR, plus shocks, X Rays, Cosmic Rays, etc. • The full ALMA sensitivitywillalsoallowdetection of weakerlinesor • details of H2O linessuch as: • - Absorption lines • - Outflows • - Isotopologues H218O, H217O (possibly HDO, D2O?) • - Othermoleculesdetected in Mrk 231: OH+, H2O+ (related to H2O and • allowing diagnostic of XDR chemistry), HF, etc. • - And manyothermoleculesallowing, togetherwith H2O, furtherchecks • of the ISM of mergernuclei for theirphysical conditions, chemistry, • dynamics, AGN influence, etc.

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