AGN and the Herschel picture of steady galaxy evolution and

AGN and the Herschel picture of steady galaxy
evolution and starbursts
Galaxies vs. SMBH
Castellammare del Golfo, June 25, 2013
Dieter Lutz
COSMOS 24/100/160 µm (Herschel PEP survey + MIPS)
Outline
•  Herschel surveys and the cosmic infrared background
•  Infrared SEDs and the roles of ‘main sequence’ steady evolution and
of mergers in the galaxy population out to z~2
•  Rest frame FIR as SF indicator in AGN hosts: strengths and limitations
•  Herschel and star formation in high-z AGN: Results and implications
for evolutionary paths
Related to talks by Santini, Rosario, Mullaney, Zamorani, Netzer, Rovilos,
Lamastra (at least…)
Discussion session later today
PACS Evolutionary Probe (PEP) GT survey:
GOODS, COSMOS,….
Data released at http://www.mpe.mpg.de/ir/Research/PEP/public_data_releases.php
Jose Acosta
Bruno Altieri
Paola Andreani
Herve Aussel
Stefano Berta
Angel Bongiovanni
Margherita Bonzini
Damien Le Borgne
Drew Brisbin
Marcella Brusa
Hector Castaneda
Antonio Cava
Jordi Cepa
Andrea Cimatti
Emanuele Daddi
Helmut Dannerbauer
Helena Dominguez-Sanchez
David Elbaz
Emeric Le Floc’h
Natascha Förster Schreiber
Reinhard Genzel
Ignacio Gonzalez
Gianluigi Granato
Andrea Grazian
Carlotta Gruppioni
Martin Harwit
Ho-Seong Hwang
Georgios Magdis
Manuela Magliocchetti
Benjamin Magnelli
Roberto Maiolino
Leo Metcalfe
Marco Mignoli
Hagai Netzer
Raanan Nordon
Koryo Okumura
Ana Perez
Ismael Perez Fournon
Albrecht Poglitsch
Paola Popesso
Lucia Pozzetti
Francesca Pozzi
Laurie Riguccini
Giulia Rodighiero
Jose Miguel Rodriguez
David Rosario
Amelie Saintonge
Fadia Salmi
Mara Salvato
Miguel Sanchez
Paola Santini
Joana Santos
Li Shao
Eckhard Sturm
Linda Tacconi
Margherita Talia
Silvia Tomassin
Ivan Valtchanov
Michael Wetzstein
Eckhard Wieprecht
Stijn Wuyts
Current deep far-infrared data (4’x4’ cutout in UDF region)
MIPS
SPIRE
SPIRE
GOODS, PEP, HerMES, LESS
PACS
SPIRE
PACS
LABOCA
PACS
Herschel resolves the majority of the Cosmic Infrared Background
Berta+10,11, Magnelli+13,
Oliver+10, Clements+10,
Bethermin+12…
Resolved into individually detected sources:
(~35% @ 70µm)
~75% @ 100µm and 160µm
~15% - 6% @ 250 - 500µm
No evidence for a truly diffuse
extragalactic background, COBE
measurements accounted for
How we looked at (local) infrared galaxies some years ago….
Normal galaxy
2 MSun/yr
disk
low
several kpc
on
cool
high
LIRG
Star formation rate
Morphology
AGN importance
Extent of star formation
Position wrt `main sequence’
Dust temperature from FIR
Ratio PAH/FIR
…
CO conversion factor
‘Star formation efficiency’ LIR/LCO
Kennicutt-Schmidt relation
FIR line deficits
…
ULIRG
200 MSun/yr
major merger
high
few 100pc
above
warm
low
Main sequence shi, for larger gas frac2on Star forma,on rate Tacconi+13
? ? Stellar mass ~2007: Something is different at higher z
The ‘IR excess’: z~2 SFRs overpredicted if
based on 24µm and local templates
SF Template mismatch or obscured AGN?
Papovich+07, Daddi+07
z~2 SMGs have stronger PAH than local
HYLIRGs, more similar to lower luminosity
ULIRGs
Lutz+05, Valiante+07, Pope+08,…
The IR ‘excess’ – seen beyond any doubt in first Herschel data
Nordon+ 10 (z~2)
Elbaz+10
Better reference than LIR is the ‘main sequence’ of star forming
galaxies
=IR/8um
Elbaz+11
Nordon+12
Far-infrared SEDs in relation to the main sequence
TDust increases with MS offset & SSFR [also with decreasing metallicity]
Magnelli+ in prep, see also Magdis+12
Molecular gas mass functions since z~3
Berta+ in press 1304.7771: CO mass function
using Herschel data and
•  Specific attenuation method of Nordon+13
•  PHIBSS depletion time scaling tDep~(1+z)-1
(Tacconi+13)
Dustiness
Star formation rate
A hierarchy of star formation indicators:
‘Highest’ SFR:
Herschel FIR (+UV)
‘High’ SFR:
Spitzer mid-IR (+UV)
(Herschel recalibrated)
‘ Low’ SFR:
Rest UV/optical SED fitting or recipes
Limits between these regimes depend on redshift and
survey practicalities…
The lesser role of z~2 starbursts
Starbursts:
2% of z~2 massive galaxies
10% of SFR from z~2
massive galaxies
All the Rest is on
main sequence
Rodighiero+ 2011
A morphological `main sequence’
Wuyts+ 2011.
Is it worth bothering about AGN host SF?
•  Similar cosmic evolution of SF and accretion
•  MBH-Mbulge relation
•  Role of AGN in quenching star formation?
Scales:
-  Star formation on ~kiloparsec scales
-  AGN feeding on <milliparsec
-  How to shed the angular
momentum?
Star formation in AGN hosts: some basic questions
•  Is there correlation between accretion rate and star formation rate?
SFR
LAGN
… would indicate a causal link and some level of synchronisation
•  What are the controlling mechanisms?
–  Mergers?
–  ‘Secular’ disk instabilities and clumps / bars / nuclear spiral structures/
stellar winds
Dustiness
Star formation rate
A hierarchy of star formation indicators
‘Highest’ SFR:
Herschel FIR (+UV)
‘High’ SFR:
Spitzer mid-IR (+UV)
(Herschel recalibrated)
‘ Low’ SFR:
AGN
Rest UV/optical SED fitting or recipes
Limits between these regimes depend on redshift and
survey practicalities…
To which extent can we trust rest FIR to be host dominated?
Be quantitative!
•  [Approach 0: Models of intrinsic AGN SED? Can produce almost any SED,
depending on the imposed dust configuration (which may not be ‘real’)…….]
•  Approach 1: Construct intrinsic AGN SEDs of local AGN, decomposing SEDs
of sources with the help of Spitzer-IRS spectra
•  Approach 2: Analyse MIR/FIR vs. FIR/FIR color/color diagrams of AGN+host
vs. inactive galaxies
Conclusion from approaches 1+2:
In some (in particular luminous) AGN the rest frame FIR can be AGN dominated,
but the average emission of typical AGN ensembles under study is dominated by
host star formation
Reconstructing intrinsic AGN SEDs
COSMOS bright high-z AGN
Mullaney+11
QSO SEDs from Netzer+ 2007
FIR is SF indicator down to L(FIR)~0.1 L(BOL,AGN)
AGN contribution to FIR: Mid- and far-infrared colors
Hatziminaoglou+10, Rosario+12 (this plot)
The SFR vs LAGN plane: Merger vs. secular?
Rosario+ 2012
(see also Lutz+10, Shao+10, Mullaney+12, Rovilos+12,
Page+12, Harrison+12)
The effect of field sizes, depths, (non)detections…
Large area, luminous AGN, FIR detections only
(e.g. Hatziminaoglou+10, Dai+12)
Deep field, moderate luminosity AGN
(e.g. Mullaney+12)
Rosario+12: Fields, and detections vs. stacks of nondetections separated
Published results consistent once considering specific approach, and field size/statistics
Do we see evidence for quenching at high LAGN??
Harrison+12
COSMOS XMM AGN z=1…3
250µm detection fractions:
All
Clean & zspec
Log(Lx) 43…44 119/417
29/52
Log(Lx) 44…45 152/484
49/94
GOODS-N, Herschel-Spire 250µm (Page+12)
Comparison of SF in AGN hosts to non-AGN galaxies:
•  Compared to in-active galaxies (both SF and passive) of same stellar
mass (Santini+12)
‘Enhanced’
•  Compared to the main sequence of star forming galaxies (Mullaney
+12, Santini+12, Mainieri+12, Rosario+13)
‘Marginally lower’
‘Broadly consistent’
‘Comparable’
•  Most hosts of X-ray AGN from Chandra and XMM surveys
(L2-10<~1044) can be dusty ‘normal’ SF galaxies near the main
sequence (Rosario+13)
Different perspective
Mullaney+12
Average SFR and average
BHAR f(host mass) in star
forming galaxies
Consistency with merger models?
Schematic: Netzer+09
Cox+06, Wuyts+10 merger models
(Gadget-2 hydro simulations)
Re-visualized into the LSF/LAGN
plane
Be aware of the underlying
assumptions!
‘Secular mechanisms’: clump migration in high-z turbulent disks?
Bournaud+ 11a,b, Gabor+ 13
Averaging, timescales, and variability
When trying to infer controlling mechanisms, be aware of
•  Many Herschel studies present average SFRs for a certain population
(sometimes even average BH accretion rates). Intrinsic spread is significant!
•  Timescales:
– 
– 
– 
– 
AGN variability: <<Myr
Large host-wide SFR variations convolved with response time of FIR: Ten(s) of Myr
Galaxy evolution timescales (e.g. shift of MS, decline of SFRD): Gyr
Possibility of delays SF/accretion
•  Don’t over-average! We started out trying to understand the similarity of
cosmic star formation history and accretion history…
Two simple models
Hickox+1306.3218 toy model
•  Adopt IR lum. Function (Gruppioni+13)
•  Average <SFR>/<BHAR>=3000
•  Fluctuations BHAR/<BHAR> power
law with Schechter cut
Neistein & Netzer 1302.1576
•  SAM in which minor/major mergers
trigger SF bursts, also background SF
•  4% of mergers accompanied by nearEddington AGN activity
•  Different time responses
Fitting the diagram necessary but not sufficient to understand the mechanisms…
Summary
• 
Herschel has resolved the cosmic infrared background around its peak
• 
Like many other properties, IR SEDs of z=0-2 infrared galaxies are best described in
relation to the evolving main sequence of star forming galaxies. Most star formation
happens near the main sequence.
• 
Good progress in determining mean SFR of X-ray AGN hosts as function of LAGN,z
• 
Predominantly secular evolution of AGN hosts, along with inactive ‘main sequence’ star
forming galaxies, but mergers likely important at z<1 and high AGN luminosity.