Dusty Universe Asantha Cooray • Far-Infrared Background • Dusty galaxies and their role in galaxy formation and evolution • Far-IR spectroscopy as a probe of interstellar medium and AGN activity • Review of results from Herschel Space Observatory and ALMA Outline Asantha Cooray, UC Irvine Dusty Universe 2016 5 10 3 Microwaves 10 -1 sr Optical -2 1 10 X-ray UV -1 Infrared 10 Gamma-ray Intensity nW m -3 Radio 10 -5 10 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 10 10 10 10 10 10 10 10 10 10 10 Wavelength (meters) Cosmic Background Light Asantha Cooray, UC Irvine Dusty Universe 2016 100 DIRBE CIBER -1 HST UVS/STIS IRAS sr -2 IRTS 10 Galaxy PACS nW m FIRAS counts SPIRE IRAC HESS ISO Intensity 1 MIPS SCUBA 0.1 1.0 10.0 100.0 Wavelength Cosmic Background Light Asantha Cooray, UC Irvine Dusty Universe 2016 Star Formation in the Rosette Nebula PACS 70 & 160 um + SPIRE 250 um 250µm 350µm 500µm 10 arcmin GOODS-N • FIRAS total background Source Counts 250, 350, 500 µm 15%, 10%, 6% • P(D) 250, 350, 500 µm 65%, 60%, 45% confusion confusion σ σ 5 5 • Stacking: 250, 350, 500 µm 80%, 80%, 85% Of course: The remainder are the most interesting sources! E.g. z > 3 galaxy populations Resolving the extragalactic background spectrum Asantha Cooray, UC Irvine Far-Infrared 2016 AAS Unsolved problems in far-infrared astronomy? • How do dusty, starburst galaxies assemble? • Where are luminous infrared galaxies today? • How do starbursts relate to dark matter? • What is the role of dust in star formation? • What is the connection between dusty star formation and AGNs? PACS PACS SPIRE SPIRE SPIRE Z=0 Z=1 Z=4 Herschel Extragalactic Surveys - Observe at SED peak - Bolometric far-IR luminosities - Large and uniform samples ANGULAR RESOLUTION SURVEY SPEED Herschel Science Motivation HERMES INFORMATION ON THE WEB: HERMES.SUSSEX.AC.UK AND HERSCHEL.UCI.EDU Asantha Cooray, UC Irvine Dusty Universe 2016 2000 ULIRGS Star-Formation 200 Rate in solar Herschel/SPIRE masses per year LIRGS 20 MILKY-WAY LIKE 2 (~Milky-way SFR) (i) ULIRGS typically have about ~1010 solar masses in stars (ii) So the time scale for star-formation is [M*/(dM*/dt)] ~ 100 Million years What kind of galaxies did we detect with Herschel? Asantha Cooray, UC Irvine Dusty Universe 2016 Optical Universe Infrared Universe major merger ULIRG AGN elliptical or heavy bombardment 1000 100/yr) o 10 SFR (M 1 0.1 0.5 Gyr 1 Gyr 1.5 Gyr 2.0 Gyr 2.5 Gyr e.g. Hopkins et al. 2009, Narayanan et al. 2009 What are Dusty Star Forming Galaxies? Illustration from Caitlin Casey Optical Universe Infrared Universe major merger ULIRG AGN elliptical or heavy bombardment Peak SFR “feedback 1000 processes?” Slow buildup exhausting of stellar 100/yr) SF fuel? o mass... Peak 10 SFR (M BH Phase old stellar population 1 0.1 0.5 Gyr 1 Gyr 1.5 Gyr 2.0 Gyr 2.5 Gyr Active ULIRG e.g. Hopkins et al. 2009, Phase Narayanan et al. 2009 T~100Myr What are Dusty Star Forming Galaxies? Illustration from Caitlin Casey Redshift distribution of SPIRE Sources? Alex Amblard et al. 2010 (ex-UCI postdoc; now NASA Ames) 102 101 z=0 z=1 z=4 100 −1 F (mJy) 10 10−2 10−3 100 101 102 103 (μm) Naive expectation based on the SED: The surface density of 350 μm selected S250 > S350 > S500: z < 2 sources (z~1.8 to 3) S350 > 20 mJy S250 <~ S350 > S500: z ~ 2 to 3 is ~800/deg2 S250 < S350 < S500: z > 4 Amblard et al. 2010 sub-mm colors as a mechanism to select z > 2 galaxies Redshift distribution of SPIRE Sources? 350μm selected galaxies > 5σ are at mostly at z = 2.2 ± 0.6 In red and blue additional color cuts on 500/250 ratio (red selects higher-z end with “redder” colors) The “statistical” redshift distribution implied by SPIRE colors for the 1686 The surface density of 350 m selected µ sources sources (z~1.8 to 3) S350 > 20 mJy [equivalent to fitting each SED with is ~800/deg2 a single-temp model and marginalizing over T,β] (Hughes et al 2002; Aretxaga et al. 2007) Amblard et al. 2010 Caitlin Casey et al. 2012 Redshift distribution of (ex-UCI postdoc; SPIRE Sources? UT Austin faculty) (LRIS sources) Keck LRIS/DEIMOS followup. z peak is around z~1 (250 micron dominated) ~1000 redshifts in the optical Redshift gap; z > 1.5 highly incomplete. Bethermin et al. 2012 N (>S) N N (>S) N ⨂ = Probability Flux mu Flux Intrinsic Source Count Magnification Cross Section Lensed Source Count Negrello et al. 2010 Science Julie Wardlow et al. 2013, ApJ (UCI ex-postdoc; Durham lecturer) Lensing galaxy selection at sub-mm wavelengths > 95% efficient The Nature of Brightest high-z Herschel Galaxies Asantha Cooray, UC Irvine Dusty Universe 2016 Bootes/NDWFS/SDWFS 16 sqr. degrees • Lensing: Flux boosted (magnified) • Can study fainter objects than usually available. • Can study spatial distribution of gas, dust, stars at higher resolution than with normal galaxies at the same distances. The Nature of Brightest high-z Herschel Galaxies Negrello et al. 2010 Science; Wardlow et al. 2012, ApJ; Bussman et al. 2012 ApJ Asantha Cooray, UC Irvine Dusty Universe 2016 Source CO Redshift GBT CARMA CSO High-Resolution Imaging Keck SMA JVLA Extensive Ground-based Follow-up Observations Asantha Cooray, UC Irvine Dusty Universe 2016 Jae Calanog UCI PhD 2014 We now have 100 images like these in total with Keck/LGS AO/HST Keck LGS-AO Imaging Fu et al. 2012; Bussmann et al. 2012; Fu et al. 2013; Calanog et al. 2014; Timmons et al. 2015 Asantha Cooray, UC Irvine Dusty Universe 2016 Planck H-ATLAS (brightest source) 550 μm 250-500 μm S250 = 320 ± 20 mJy S350 = 380 ± 60 mJy S550 = 1.07 ± 0.12 JY S500 = 300 ± 20 mJy S350 = 1.1 ± 0.2 JY ZCO = 3.26 CARMA A lensed Planck source resolved by Herschel (in ATLAS) Fu, Hai et al. 2012, ApJ Asantha Cooray, UC Irvine Dusty Universe 2016 LFIR = 1.6 X1013 L⊙ SFR ~ 1900 M⊙/yr TDUST = 62 ± 3 K 1 ARCSEC No evidence for AGN MDUST = 6 X108 M⊙ MSTARS = 3 X1010 M⊙ MGAS = 7 X1010 M⊙ MDYNAMICAL = 3 X1011 M⊙ Gas-rich (70% of baryons in gas) Young (MSTARS/SFR~20 Myr) Short Star-burst (MGAS/SFR~40 Myr) Hai Fu et al. 2012, ApJ (ex-UCI postdoc; Iowa faculty) A lensed Planck source resolved by Herschel (in ATLAS) Fu, Hai et al. 2012, ApJ Asantha Cooray, UC Irvine Dusty Universe 2016 H-ATLAS: 650 sq. degrees. ~2 lensed Planck CSC Starbursting knot in a sources. One in HerMES over 370 sq. degrees. spiral galaxy. Disk is mostly an old stellar population. Lensed optical arc Lensed Herschel-detected source (starbursting clump) 1” z=1.68, z determined from the Herschel-SPIRE/FTS spectrum with the 158 micron CII line George et al. 2014; Timmons et al. 2015 Nick Timmons UCI PhD 2017 Herschel Lensed Sources Asantha Cooray, UC Irvine Dusty Universe 2016 H-ATLAS: 650 sq. degrees. ~2 lensed Planck CSC Source reconstructed: SMA/JVLA (red) sources. One in HerMES over 370 sq. degrees. and Keck/Hubble (green/blue) n = 103 Galactic SF Regions L[C II ] /LCO(1 0) = 4100 Normal Galaxies n = 102 10− 2 StarburstNuclei n = 104 Local ULIRGs HATLAS J132427 LESS J033229.4 BR1202-0725 SMM J2135 5 FIR n = 10 HDF 850.1 /L ] HFLS 3 II − 3 [C 10 SDP.81 L ID 141 NBv1.43 n = 106 − 4 4 3 2 10 G0 = 10 G0 = 10 G0 = 10 10− 7 10− 6 10− 5 LCO(1 0) /LFIR 1” z=1.68, z determined from the Herschel-SPIRE/FTS spectrum with the 158 micron CII line George et al. 2014; Timmons et al. 2015 Herschel Lensed Sources Asantha Cooray, UC Irvine Dusty Universe 2016 Discovery in H-ATLAS during SDP: Negrello et al. 2010 Science z=0.3 elliptical (Sloan LRG) z=3.04 DSFG 2010 Keck+SMA 2015 HST+ALMA SDP.81 Asantha Cooray, UC Irvine Dusty Universe 2016 Dye et al. 2015 SDP.81 Negrello et al. 2010; Vlahakis et al. 2015; Dye et al. 2015; Swinbank et al. 2015;… (6 papers with ALMA) Asantha Cooray, UC Irvine Dusty Universe 2016 50 pc resolution in a z of 3 galaxy thanks to lensing + ALMA SDP.81 Negrello et al. 2010; Vlahakis et al. 2015; Dye et al. 2015; Swinbank et al. 2015;… (6 papers with ALMA) Asantha Cooray, UC Irvine Dusty Universe 2016 Promise of Herschel in Lensing Studies • ~0.2/sq. deg (S500>100 mJy) lensed source - identified ~90% efficiency. • Herschel extragalactic surveys: ~1200 sq. degrees, so ~250 lensed galaxies. • Compared to ~200 lensed galaxies now known in optical and radio 500 um peaked sources S250 < S350 < S500: z > 4? *Confusion reduced S(500) – fS(250) 250 um 350 um 500 um * HST WFC3+ACS 250 um 350 um 500 um * FLS3 z=6.34 Dowell et al. 2014 ApJ technique IRAM 1.1mm z = 6.34 Dusty Starburst Galaxy in HerMES Riechers, D. et al. Nature 2013; Cooray et al. 2014 Asantha Cooray, UC Irvine Dusty Universe 2016 250 um 350 um 500 um * ! Asantha Cooray, UC Irvine Dusty Universe 2016 z=2.1 z=6.3 Weakly lensed by two z=2.1 galaxies with magnification 12 LFIR = 6X10 L⊙ MDUST > 109 M⊙ 1.6 +/- 0.3 SFR ~ 1300 M⊙/yr MSTARS ~ 5X1010 M⊙ 11 TDUST = 55 ± 10 K MGAS ~ 10 M⊙ [G2 identification in R13 as K-band ID of FLS3 incorrect] No evidence for a quasar/massive AGN! z = 6.34 Dusty Starburst Galaxy in HerMES Riechers, D.