Towards a Complete Census of Extreme Starbursts in the Early Universe

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1 Towards a Complete Census of Extreme Starbursts in the Early Universe Caitlin M. Casey, University of Cambridge (University of Hawai i - September 2010) Scott Chapman, Ian Smail, Rob Ivison, Andrew Blain, Roberto Neri, Frank Bertoldi, Linda Tacconi, Laura Hainline, Karin Menedez-Delmestre, Mark Swinbank, Kristen Coppin, Rob Beswick, Tom Muxlow, and others... Stars and Galaxies Conference - 9 April 2010 Gainesville, FL, USA

2 1. Evolution of Ultra-luminous Galaxies

3 Cosmic Time (Sanders et al. 1988a,b) dusty, high star formation massive early type galaxy merging disk galaxies ULIRG evolution (UltraLuminous InfraRed Galaxies) L > Lo quasar/ xray AGN 1. Evolution of Ultra-luminous Galaxies

4 SFR (Mo/yr) merger ULIRG QSO elliptical BIG Peak QUESTIONS: SFR Peak BH Volume Density? Phase ULIRGs build stellar mass very quickly, Progenitors? big contribution to the Cosmic SFRD at z~2. Details of triggering mechanism? e.g. Narayanan et al Gyr 1 Gyr 1.5 Gyr 2.0 Gyr 2.5 Gyr Active ULIRG Phase T~100Myr 1. Evolution of Ultra-luminous Galaxies

5 Observing ULIRGs. (at high-z) 1. Evolution of Ultra-luminous Galaxies 2. Far-IR Selection Effects

6 SubMillimeter Galaxies SMGs The HDF at 850um Radio S mjy SCUBA (JCMT) LABOCA (APEX) 850 µm 870 µm Radio ID Spec-z Subsample: (~75 galaxies in multiple fields) z 2.2 SF R 1000 M yr 1 M M Chapman et al. 2005, Pope et al Optical BUT... JCMT (SCUBA/SCUBA2) 2. Far-IR Selection Effects

7 ULIRG Temperature Selection Bias 250um, 350um, 500um (Described in Eales et al. 2000, Blain et al. 2004, Chapman et al. 2004) 2. Far-IR Selection Effects

8 z 2 S 850 T 3.5 d L F IR SMGs are cold and don t represent all ULIRGs at z~2....also radio-id sample is biased towards z<4. 2. Far-IR Selection Effects

9 Select at 70 µm : (8 Galaxies) Select at 250µm : (10 Galaxies) MIPS hot-dust ULIRGs BLAST warm-dust ULIRGs Casey et al. 2009b (MNRAS 399, 121) Td = 52 ± 10 K Td = 36 ± 7 K 70um identification of submmfaint radio galaxies Casey et al. 2010, in prep Redshift identification 2. Far-IR Selection Effects

10 70µm 250µm 2. Far-IR Selection Effects 2. Far-IR Selection Effects

11 Seeking ULIRG completeness... finding submm-faint ULIRGs, and characterizing their evolution. 2. Far-IR Selection Effects 3. Observations of submm-faint ULIRGs

12 Unbiased ULIRG Selection SMGs (JCMT/SCUBA2-1998) ) 850 µm (APEX/LABOCA ) 870 µm (CSO/SHARCII ) (Spitzer/MIPS ) (Herschel/PACS ) 70µm (Herschel/SPIRE- 2009) 350µm 1200µm (Far-infrared SED) 1100µm (IRAM 30m/MAMBO ) (LMT/AzTEC /10) 3. Observations of submm-faint ULIRGs

13 ULIRG Completeness Identification + Characterization Since this is an 8 minute NOW talk Select diverse ULIRG populations FUTURE 70um - MIPS, Casey et al. 2009b 250um - BLAST, Ivison 70um et (MIPS), al., Dunlop um et al. 2010(Herschel 350um - CSO, Kovacs 1200um et al. (MAMBO), 2006, Bussmann SPIRE, et PACS), al um 850/870um - SCUBA, 250um LABOCA, (BLAST), All SMG papers... SCUBA2 350um (CSO) 1.1mm - AzTEC, Younger et al. 2007,09a II. Secure 1.2mm - MAMBO, Optical/UV Younger spec-z s et al. 2009b Optical/UV *and* CO - Neri et al. 2003, Redshifts (e.g. Greve Keck, et VLT) al. 2005, Tacconi blank CO et redshifts al. 2006,08, Casey et al. 2010a (ALMA) mid-ir Spec - Pope et Molecular al. 2009, Gas Menendez-Delmestre 2009, Casey Observations et al. 2010, (PdBI), in prep MERLIN radio - Chapman mid-ir spectra et al. 2004, (IRS), Casey et ALMA, al. 2009a, JWST, Biggs rest-uv & Ivison spectra, 2008 x-ray, emerlin, evla... III. Characterize ULIRG evolution resolved MERLIN radio 3. Observations of submm-faint ULIRGs

14 ...Findings/Inklings L L (LIRG) (ULIRG) L (HyLIRG) IR Luminosity Number Density Dearth of high-l ( L ) hot-dust ULIRGs Casey et al. 2010a (aph/ ) Casey et al. 2010, in prep Minor Mergers? Rapid Gas Accretion? Later stage in major merger? 500M yr 1 MAJOR MERGERS, ULIRGs at LAST INFALL STAGE? HIGHEST SFRs in COLD, DIFFUSE ISM τ 100Myr 1000M yr 1 OBSERVATIONAL EVIDENCE NEEDED

15 OBSERVATIONAL EVIDENCE NEEDED HERSCHEL, SCUBA2 KECK,VLT... ID spec-z s Select diverse range winds, outflows, metallicities of z~2 ULIRGs Find z~4 ULIRGs Herschel SPIRE image of Abell 2218 ALMA Blind CO redshifts CO Survey of large ULIRG samples CO in MW-type Gals at z~2 CO excitation: gas, dust interaction Resolved CO dynamics

16 Summary STRONG TEMPERATURE BIAS OF SMGS Observations of hot-dust (and other submm-faint) ULIRGS: FAR-IR observations in um (Herschel, SCUBA2) Molecular Gas Observations (PdBI, ALMA) AGN Diagnostics: Mid-IR PAH/continuum, X-ray, MERLIN Build sample, unify selection/characterization of ULIRGs Understand extreme, obscured SF at z~2 me!