Properties of Dusty, Highly-Luminous Starbursts Back to the First - PowerPoint PPT Presentation

Properties of Dusty, Highly-Luminous Starbursts Back to the First Billion Years of Cosmic Time Dominik A. Riechers Cornell University SMG20 – Twenty Years of Submillimetre Galaxies August 02, 2017

Molecular Gas 2x2 arcmin 2 § AzTEC-3: Most Distant Massive Starburst Galaxy 2010-13 § M gas = 5.3 x 10 10 ( a co /0.8) M sun SFR: ~1100 M sun /yr …or >3 M sun / day § Early Galaxy Proto-Cluster : 11 star-forming galaxy companions within r~2 Mpc COSMOS/AzTEC-3 (z=5.3)

Molecular Gas 2x2 arcmin 2 § AzTEC-3: Most Distant Massive Starburst Galaxy 2010-13 § M gas = 5.3 x 10 10 ( a co /0.8) M sun SFR: ~1100 M sun /yr …or >3 M sun / day § Early Galaxy Proto-Cluster : 11 star-forming galaxy companions within r~2 Mpc COSMOS/AzTEC-3 (z=5.3) § 2017: - 17 z>5 DSFGs (incl. 3 at z>6) - 1 ALMA (serendip.; 1 mm) - 11 strongly lensed - 1 AzTEC 1.1 mm - 3-4 weakly magnified - 2 SCUBA 850 µm - 2-3 unlensed - 6 SPT 1.4+2.0 mm - 7 Herschel/SPIRE “Red” 250-500 µm - 15/17 from “blind” CO redshifts Riechers et al. 2010, 2013, 2014, 2017abc*; Capak et al. 2011; Walter et al. 2012; Combes et al. 2012; Vieira/Weiss et al. 2013; Strandet et al. 2016, 2017; Pavesi et al. 2017*; Fudamoto et al. 2017; Zavala et al. 2017

Riechers et al. 2013 § Most common UV/optical lines typically dust-obscured in DSFGs § DSFGs have rich (sub)millimeter/far-infrared spectra, even at z>6 Þ Main diagnostic tools to understand physical properties of intense star formation

250 - 7000 GHz Spilker et al. 2014; Zhang et al. 2017 § Probing deeper/broader by utilizing stacked spectra of lensing-magnified sources Þ powerful tool to access fainter diagnostic lines … but what can we learn from these lines?

cm/mm: rich in line + continuum diagnostics JWST SPICA ALMA+CCAT JVLA Cosmic Eyelash model SED CNO fine structure lines ISM gas coolant CO ‘ladder’ *model* total gas masses excitation, dynamics Thermal dust phys. conditions (young stars) Smail et al. 2011 star formation PAHs + SiL Swinbank et al. 2011 Synchrotron + Free-Free (AGN+SNR) star formation

cm/mm: rich in line + continuum diagnostics JWST SPICA ALMA+CCAT JVLA Cosmic Eyelash model SED Riechers et al. 2014a CNO fine structure lines 6.2 µm PAH ISM gas coolant CO ‘ladder’ *model* total gas masses excitation, dynamics Thermal phys. conditions dust (young stars) Smail et al. 2011 star formation PAHs + SiL Swinbank et al. 2011 Synchrotron + Free-Free (AGN+SNR) star formation

Carilli & Walter 2013 § >200 CO detections in DSFGs to date: - ~50 SCUBA + AzTEC + LABOCA (Bothwell+; Riechers+; Coppin+; Yun+; Huynh+, …) - ~100 Herschel (Harris+; Lupu+; Riechers+; Zavala+; Fudamoto+, …) - ~40 SPT (Weiss/Vieira+; Strandet+; Aravena+) - ~5 ACT (Su+; Roberts-Borsani+; …) - ~12 Planck (Canameras+; Harrington+) - several “misc” (Swinbank+; Lestrade+; Leung+; Tamura+; Karim+, …)

Simplest Version of “Star Formation Law”: Spatially Integrated Observables log L FIR ~ proxy for SFR L’ CO vs. L FIR as a surrogate for M gas vs. SFR One super-linear relation or Two sequences ( quiescent / starburst ) Bimodal or running conversion factor starbursts starbursts e c n …many subtleties, but: e u High-z galaxies higher on both axes MS galaxies q e s Quiescent and Starburst Galaxies n i a m log L’ CO ~ proxy for M(H 2 ) Carilli & Walter 2013 ARAA; after Daddi et al. 2010, Genzel et al. 2010

const.? • Star-forming galaxies show 10-30x higher gas fractions at z=1-3 compared to present day Increase in gas fraction likely dominantly responsible for increase in star formation history • Little evidence for significant redshift evolution in gas depletion timescales in starbursts • Þ Star formation activity is elevated, but underlying physics are similar Aravena et al. 2016 (see also Bothwell et al. 2013; Magdis et al. 2012)

Riechers et al. (2011d, 2011f); see also: Ivison et al. (2011) Early stage Intermediate stage Late stage ~30kpc & 750km/s ~20kpc & <100km/s 7-15kpc nucleus & tidal structure separation separation single broad, multi-peaked line abundant low-excitation gas Submillimeter Galaxies: Gas-Rich Starbursts along the “Merger Sequence” at z>2? Ø Nearby major mergers show increased SF efficiency relative to disks Ø SMGs could be “scaled up” versions of nearby IR-luminous galaxies/mergers Line profile and gas dynamics sometimes show evidence for major mergers

SDP-81 (z=3.0) Hodge et al. 2012 High-Resolution Molecular Line Spectroscopy w/ interferometers yields velocity fields Gas Kinematics: Evidence for 2-15 kpc, rotating gas disks in DSFGs ALMA collab. et al. 2015; Dye et al. 2015; Swinbank et al. 2015; see also Rybak et al. 2015; Hatsukade et al. 2015

HFLS3 (z=6.34): - smooth velocity profile at 0.2” res. - high velocity dispersion across 3.5 kpc - superposition of two components with very different line widths Þ likely disturbed/interacting system Riechers et al. 2013b

[CII] AzTEC-3 (z=5.30): - Little evidence for velocity gradient at 0.6” res. - high velocity dispersion across 4 kpc - Simple, broad symmetric line profile - nearby UV-bright companions 1000 km/s Þ likely disturbed/interacting system Riechers et al. 2014b

Carilli & Walter 2013 § 4 HCN & 4 HCO + & 2 HNC detections in DSFGs to date: - SMM J2135-0102 (z=2.3; HCN, tentative ; Danielson et al. 2011) - SDP 9 & 11 (z~1.7; 2x HCN, 2x HCO + , 1x HNC; Oteo et al. 2017) - ACT J0210+0015 (z~2.6; HCN, HCO + , HNC; Riechers+) - Planck G092.5+42.9 (z~3.3; HCO + ; Riechers+) also: several S/N~3 features in SPT stack (Spilker et al. 2014)

Example: HFLS3 (z=6.34): 7 H 2 O lines detected up to E upper ~ 450 K, (shallow) coverage of 22 lines up to E upper > 1200 K Lines seen in emission, approaching strengths comparable to the brightest CO lines Þ Given the large difference in n crit to CO, significant collisional excitation is unlikely Þ H 2 O excitation is indistinguishable from Arp 220 Þ Consistent with radiative excitation in warm, obscured starburst Riechers et al. 2013b

Linear relations: - H 2 O lines dominated by FIR pumping H 2 O traces dense, warm gas at high t dust - Yang et al. 2016

Carilli & Walter 2013 § >60 [CII] detections in DSFGs to date § (much) smaller samples for [OI]63, [OIII]88, [NII]122 & 205 [CII] associated with multiple ISM phases (neutral/ionized gas, star forming regions…) à need multiple lines to study ISM actual properties

CI à CII @11.26 eV à [CII] from PDR+HII HI à HII @ 13.6 eV NI à NII @14.53 eV à [NII] from HII only [CII] 158µm & [NII] 205 µm have similar critical density in HII regions à [CII]/[NII] ratio gives fraction of [CII] from neutral vs. ionized ISM à [NII]122/[NII]205 gives HII region density

Observed: [CII], [NII]122, [NII]205 Have: - [CII] fraction from PDRs - HII region density [OI] from PDRs à [CII]/[OI] sensitive to PDR density

• CLOUDY models: LOW [CII] High density and radiation from ionized intensity à high [CII]/[NII] gas • Similar ratio in nearby ULIRGs, dusty LBGs, DSFGs, QSOs à [NII] coming from diffuse (non-starbursting) gas • high [CII]/[NII] in dust-poor LBGs à similar to nearby HIGH [CII] low-metallicity dwarfs from ionized gas Updated from Pavesi, DR et al. 2016

Cormier et al. 2015 metallicity metallicity ~T dust [CII]/[NII] not very sensitive to T dust & lines have similar n crit in HII regions [CII]/[NII] appears to rise steeply with metallicity à Fraction of [CII] from HII regions seems to decrease à Low [NII] thus may indicate that most N (and C, O) in higher ionization state à Consistent with rising [OIII]/[NII] & [OIII]/[CII] with metallicity

Assuming [CI] is optically-thin and has a standard abundance: ~2-3x higher inferred M(H 2 ) than with standard a CO à either CO underpredicts gas mass, or C has higher than nominal abundance à M. Bothwell’s talk Bothwell et al. 2017 (see also Weiss et al. 2005; Riechers et al. 2009)

M100 Herschel/SPIRE ALMA Spectral Energy Distribution Credits: X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech Flux density 250 350 500 µm wavelength - idea: z>4 galaxy dust SEDs preferentially peak beyond 500 µm Þ can use (sub)mm colors to determine reasonable photometric redshifts Þ “red” sources are strong candidates for starbursts at the earliest epochs Riechers et al. 2013b

10 10 SPIRE-Red SPIRE-Red SPIRE+SPT-Red 14 SPT SPT-Red 8 8 12 10 6 6 8 N N N 4 4 6 4 2 2 2 0 0 0 2 3 4 5 6 7 2 3 4 5 6 7 2 3 4 5 6 7 redshift redshift redshift SPT vs. Herschel-Red selection (CO spec-z only): - strongly overlapping, but different redshift distributions - indistinguishable when only taking “red” SPT sources Þ perhaps not surprising: preferentially followed up 870 µ m/1.3mm-bright Herschel-Red sources Þ Combine samples to obtain median redshift: z med =4.42

Beyond Herschel-Red Selection: Red source(s) w/ SEDs rising to 870 µm Only 1/300 red sources followed up over ~1000 deg 2 w/ SCUBA-2/LABOCA: Unlensed Hyper-LIRG: 25 mJy @870 µm Riechers et al. 2017a