SLIDE 1 Understanding Submillimetre Galaxies: Lessons from Low Redshifts
#SMG20 – Durham 2017
Paul van der Werf
Leiden: Marissa Rosenberg Rowin Meijerink Saskia van den Broek Edo Loenen Kirsty Butler Cardiff/ESO:Padelis Papadopoulos ESTEC: Kate Isaak Groningen: Marco Spaans Madrid: Santiago Garcia-Burillo MPIfR: Axel Weiß UCL: Thomas Greve
SLIDE 2 Know your classics
- Casey, Narayanan, & Cooray 2014, Phys Rep, 541, 45
- Carilli & Walter 2013, ARA&A, 51, 105
- Blain, Smail, Ivison, Kneib & Frayer, 2002, Phys Rep, 369, 111
- Scoville, 2012, Canary Winter School, arXiv/1210.6990
SLIDE 3 Outline
- ULIRGs vs. SMGs
- Local physical conditions from FIR-submm spectra
- Molecular gas mass
- Gas outflows
SLIDE 4 From IRTRONs to ULIRGs
- 1984-1985: IRAS (“ultra-high luminosity”: Houck et al., 1985)
SLIDE 5
Local ULIRGs are major mergers
(GOALS - Evans et al.)
At LIR > 5×1012 Lʘ, all (U)LIRGs show merging signatures
SLIDE 6 Babies or monsters?
(Sanders et al., 1988)
- Cool ULIRG
- Warm ULIRG
- QSO
SLIDE 7 Extreme star formation
LIR SFR LIR/LCO SFR/MH2 SFE
(Gao & Solomon, 2001)
1 1 1 1 1 H
400 : KL
Orion 54 : 1
8 . 1 : GMCs Galactic 5 . 1 : Way Milky 100 : ULIRGs
2 FIR
M L M L M L M L M L M L
SLIDE 8
Strong evolution
(Casey et al., 2014)
SLIDE 9 ULIRGs vs. SMGs
- At same LIR, Td is lower at
high z
- CO disks in SMGs are larger
than in ULIRGs
Galaxy Main Sequence?
Where does the analogy break down? (Casey et al., 2014)
SLIDE 10
ULIRGs vs. SMGs
NB: selection, diversity
CO ladders (Greve et al., 2014)
SLIDE 11 Outline
- ULIRGs vs. SMGs
- Local physical conditions from FIR-submm spectra
- Molecular gas mass
- Gas outflows
SLIDE 12
Mrk 231
Herschel SPIRE FTS (Van der Werf et al., 2010)
SLIDE 13
Mrk 231
CO ladder (Van der Werf et al., 2010)
2 PDRs + XDR 6.4:1:4.0 * 28 erg cm-2 s-1 G0=104.2 n=104.2, FX=28* n=103.5, G0=102.0 n=105.0, G0=103.5
SLIDE 14 XDRs vs. PDRs
- X-rays penetrate much larger column densities than UV photons
- Gas heating efficiency in XDRs is ≈10—50%, compared to <1% in
PDRs
- Dust heating much more efficient in PDRs than in XDRs
- CO/[CII] elevated in XDRs compared to PDRs
Physical differences
SLIDE 15
XDRs vs. PDRs
CO ladder (Spaans & Meijerink, 2008)
Identical total incident energy
SLIDE 16 CO cooling fraction as AGN tracer
HerCULES sample
PAH6.2 EW traces starburst fraction
IRASF05198-2524 (Rosenberg et al., 2015)
SLIDE 17
CO ladders of local (U)LIRGs
Herschel SPIRE/FTS data from HerCULES (Rosenberg et al., 2015)
Identical total incident energy
α = CO(12−11)+CO(13−12) CO(5−4)+CO(6−5) α < 0.33 0.33< α < 0.66 α > 0.66
SLIDE 18 Starburst and AGN tracers
Principal component analysis of HerCULES lines
best AGN indicator
starbursts
prefer AGNs AGNs starbursts (Van den Broek et al., in prep.)
SLIDE 19 MPDRs and CRDRs
CO ladder (Kazandjian et al., 2015)
- For almost all starbursts, UV
heating (PDR) is insufficient.
- MPDRs or CRDRs are needed.
- Extreme MPDRs are hard to
distinguish from XDRs.
SLIDE 20 Fine-structure line deficits
GOALS sample - [CII] 158μm, [NII] 122/204μm, [OI] 63μm, [OIII] 88μm (Casey et al., 2014) (Diaz-Santos et al., 2017)
- ffset only due to larger size?
SLIDE 21
[CII] line deficit at for SMGs
SPT sample (Spilker et al., 2016)
SLIDE 22
Line deficits and physical conditions
PDR modeling based on [CII], [OI] and [NII] (Diaz-Santos et al., 2017)
Transition in properties at ∑IR = 5×1010 Lʘ/kpc2
SLIDE 23 Outline
- ULIRGs vs. SMGs
- Local physical conditions from FIR-submm spectra
- Molecular gas mass
- Gas outflows
SLIDE 24 H2 mass from observations of other tracers
the invisible molecule
H2
- bserve excitation of other species
= observe H2 through its collisions Modeling excitation yields conversion factor to H2 mass
SLIDE 25
Star formation laws and αCO
(Casey et al., 2014)
SLIDE 26
αCO from improved data and modeling
See talk by Weiß Weiß et al., in prep.
SLIDE 27 Outline
- ULIRGs vs. SMGs
- Local physical conditions from FIR-submm spectra
- Molecular gas mass
- Gas outflows
SLIDE 28 Self-regulated galaxy buildup
gas inflow
extremely difficult to
Theoretical paradigm
star forming gas
Infrared, Hα, CO, HCN, dust, etc
feedback
Supernova remnants, AGNs
gas outflow
CO, Hα, X-rays, etc.
SLIDE 29
Mrk 231 outflow in CO
(Feruglio et al., 2010) H2O absorption H2O emission
SLIDE 30
Mrk 231 outflow in CO and HCN
(Aalto et al., 2014) The outflowing molecular gas is dense!
SLIDE 31 Multi-phase outflows
CO ladder (Wada, Schartmann, & Meijerink, 2016)
- Complex structure and velocity field
- Out-of-equilibrium chemistry
- Relative and total masses?
- Observations of multiple phases needed
SLIDE 32 Hα supernebulae around (U)LIRGs
NGC6240 (Armus et al., 1990)
SLIDE 33
Ubiquity of molecular outflows
Do galaxies where the integrated spectrum does not show wings have no outflows?
(García-Burillo et al., 2014) NGC1068, ALMA
SLIDE 34
NGC1068 velocity field
SLIDE 35
NGC1068 outflow
SLIDE 36
IRAS 17208-0014
SLIDE 37
IRAS 17208-0014 outflow
(García-Burillo et al., 2015)
SLIDE 38
Driving
(García-Burillo et al., 2015)
SLIDE 39
Outflow tracers
Can we use OH+ and CO(9−8) to trace high-z outflows?
SLIDE 40
OH+ outflow at z = 2.41
SLIDE 41
OH+ in Arp220
Herschel/SPIRE, Rangwala et al., 2012
SLIDE 42
Hot off the press: OH+ in Arp220 with ALMA Band 10
NH2 OH+ red wing OH+ main absorption OH+ blue wing
SLIDE 43 Open questions
- CO ladder: what is the role of mechanical and cosmic ray heating and
what can we learn from it?
- Fine-structure lines: are there deviations from the low-z relation? What
happens at low metallicities?
- Outflows: how do outflow properties depend on galaxy properties?
What is the mass outflow rate? What happens to the outflowing gas?
- Extreme star formation: Is Eddington-limited star formation really
relevant?
- Arp220: What is happening in the obscured nuclei? How can we tell?
- SMGs vs. ULIRGs: what do the differences mean?
- IMF: universal? Top-heavy? How can we tell?
