Star formation suppression by an AGN (in NGC 1266 and maybe more) - - PowerPoint PPT Presentation
Star formation suppression by an AGN (in NGC 1266 and maybe more) Katherine Alatalo Infrared Processing & Analysis Center Caltech kalatalo@ipac.caltech.edu ! with Philip Appleton, Carl Heiles, Kristina Nyland, Mark Lacy, Sabrina Cales,
kalatalo@ipac.caltech.edu ! with Philip Appleton, Carl Heiles, Kristina Nyland, Mark Lacy, Sabrina Cales, Ute Lisenfeld, Jeff Rich, Theodoros Bitsakis, Philip Chang, Timothy Davis, P.T. de Zeeuw, Susana Deustua, Genevieve Graves, Lisa Kewley, Lauranne Lanz, Carol Lonsdale, David Meier, Sergio Martin & Patrick Ogle
Alatalo et al. 2011 NGC 1266 appears to be a “quiescent” S0
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NGC 1266 hosts a massive molecular disk (>109 M⊙) and a massive (>108 M⊙) molecular
by an AGN
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A young (1/2 Gyr) stellar population
(obvious) SF event
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Star formation is suppressed by at least a factor of 70 seen in the nucleus
HST B V I
Alatalo et al. 2011, Davis et al. 2012, Nyland et al. 2013, Alatalo et al. 2014a, 2014b (submitted)
Alatalo et al. 2011 NGC 1266 appears to be a “quiescent” S0
!
NGC 1266 hosts a massive molecular disk (>109 M⊙) and a massive (>108 M⊙) molecular
by an AGN
!
A young (1/2 Gyr) stellar population
(obvious) SF event
!
Star formation is suppressed by at least a factor of 70 seen in the nucleus
HST B V I
Alatalo et al. 2011, Davis et al. 2012, Nyland et al. 2013, Alatalo et al. 2014a, 2014b (submitted)
03h 16m 2.5s 1.5s 26’ 00’’ 25’ 40’’ 20’’ B
B-Y
Mgas ~ 4×109 M⊙ (Young et al. 2011) Moutflow ~ few×108 M⊙ (Alatalo et al. 2011, new HCN and CS(2-1) have wings) Outflow mass flux ~ 110 M⊙ yr-1 Outflow dynamical time < 3 Myr (Alatalo et al. 2011)
03h 16m 2.5s 1.5s 26’ 00’’ 25’ 40’’ 20’’ B
B-Y
1600 1800 2000 2200 2400 2600 2800 Velocity (km s-1) 0.0 0.2 0.4 0.6 0.8 1.0 Tmb (K)
CO(2-1)
Mgas ~ 4×109 M⊙ (Young et al. 2011) Moutflow ~ few×108 M⊙ (Alatalo et al. 2011, new HCN and CS(2-1) have wings) Outflow mass flux ~ 110 M⊙ yr-1 Outflow dynamical time < 3 Myr (Alatalo et al. 2011)
03h 16m 1.8s 1.4s 1.0s
45’’ 35’’ 25’’
NUV: tracing ~1/2 Gyr stellar population Current site of all molecular gas (from CO) 2 kpc
200 pc
NUV imaging show a larger distribution of young stars than the current site of the molecular gas
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A stellar population analysis shows that the population is poststarburst of age (~500 Myr) with mass fraction ~10%
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Alatalo et al. 2014a
Modeling the SED of 1266 results in SF ~ 2.2 M⊙ yr-1 is an upper limit, if all of this emission is from stars (it isn’t) and the free-free fit say SF < 0.9 M⊙ yr-1. LTIR ≈ 3 × 1010 L⊙ (1.2 × 1044 ergs s-1) Alatalo et al. 2014b, submitted 10-1 100 101 102 103 104 105 106 Wavelength (µm) 104 105 106 107 108 109 1010 1011 Luminosity (LO
Free Free Synchrotron Spitzer IRS Cold Dust AGN Stellar Full Model Keck HST 2MASS IRAC MIPS PACS SPIRE ALMA VLA
Last burst of SF happened ~500Myr ago and the nuclear molecular gas has remained since then
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SFR calculated using the free- free emission indicates a SFR
decomposed data agree)
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Σgas ≈ 104 M⊙ pc-2 (from CO, CS and HCN)
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Using dense gas (CS) size and assuming SF/CS co- spatiality, NGC 1266 is a factor
Alatalo et al. 2014b submitted
1 2 3 4 5 log(mol) (MO
2 log(SFR) (MO
1 / 1 1 / 1
1266
Milky Way1 Normal Galaxies2 LIRGS2 Normal Galaxies3 Bulges3 ULIRGs4 High-z galaxies5 Radio galaxies6
Alatalo et al. 2014a, 2014b (submitted)
collapse of a subcritical molecular disk in the already mostly old NGC 1266
Alatalo et al. 2014a, 2014b (submitted)
collapse of a subcritical molecular disk in the already mostly old NGC 1266
toward nucleus, and young stars (10% Mbulge) are formed within the 2kpc boundary
Alatalo et al. 2014a, 2014b (submitted)
collapse of a subcritical molecular disk in the already mostly old NGC 1266
toward nucleus, and young stars (10% Mbulge) are formed within the 2kpc boundary
continues toward the AGN
Alatalo et al. 2014a, 2014b (submitted)
collapse of a subcritical molecular disk in the already mostly old NGC 1266
toward nucleus, and young stars (10% Mbulge) are formed within the 2kpc boundary
injecting turbulence into the dense molecular disk, suppressing SF (x70) and driving an outflow
continues toward the AGN
Alatalo et al. 2014a, 2014b (submitted)
collapse of a subcritical molecular disk in the already mostly old NGC 1266
toward nucleus, and young stars (10% Mbulge) are formed within the 2kpc boundary
injecting turbulence into the dense molecular disk, suppressing SF (x70) and driving an outflow
radio turns off, and outflow begins falling back onto the
dissipates.
continues toward the AGN
Alatalo et al. 2014a, 2014b (submitted)
collapse of a subcritical molecular disk in the already mostly old NGC 1266
toward nucleus, and young stars (10% Mbulge) are formed within the 2kpc boundary
injecting turbulence into the dense molecular disk, suppressing SF (x70) and driving an outflow
radio turns off, and outflow begins falling back onto the
dissipates.
continues toward the AGN
Alatalo et al. 2014a, 2014b (submitted)
Case studies are great, but can’t tell us about a population.
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What is the duty cycle of the SF quenching?
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What evolutionary pictures lead to an AGN expulsion of molecular gas?
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Can we begin to understand NGC 1266-like objects?
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What is the redshift evolution of these objects?
NGC 1266 hosts an AGN-driven
set of optical features
03h 16m 1.8s 1.4s 1.0s
45’’ 35’’ 25’’ 10″
young(ish) stellar population Alatalo et al. 2014a
shocked ionized gas (Davis et al 2012)
UV
shocked ionized gas ratios + poststarburst stellar population = a Shocked Poststarburst Galaxy (spog)
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NGC 1266 is a spog.
0.5 1.0 1.5 2.0 2.5 3.0 u-r (corrected)
Parent
(a) Nparent = 130788
Seyferts
(b) Nseyfert = 4765
EW(Hδ) > 5Å
(c) NEW Hδ = 46936 9.0 9.5 10.0 10.5 11.0 11.5 log( Mgal ) [ MO
SF
(d) Nsf = 111972
LINERs
(e) Nliner = 11327
SPOGS
(f) Nspog = 1067
ELG Alatalo et al. 2014c (submitted)
when in doubt, cross-correlate with WISE
GZ sample from Schawinski et al. 2014; Alatalo et al. 2014c (submitted)
when in doubt, cross-correlate with WISE
9.0 9.5 10.0 10.5 11.0 11.5 log( Mgal ) [ MO
0.5 1.0 1.5 2.0 2.5 3.0 u-r (corrected)
LTGs ETGs
(a)
9.0 9.5 10.0 10.5 11.0 log( Mgal ) [ MO
1 2 3 4 WISE [4.6]-[12] (Vega)
(b)
1 2 3 4 WISE [4.6]-[12] (Vega)
0.0 0.1 0.2 0.3 WISE [3.4]-[4.6] (Vega)
(c)
0.5 1.0 1.5 2.0 2.5 3.0 u-r (corrected) 1 2 3 4 WISE [4.6]-[12] (Vega)
GZ sample from Schawinski et al. 2014; Alatalo et al. 2014c (submitted)
Alatalo et al. 2014c (submitted)
1 2 3 4 [4.6]−[12] (Vega)
ELG
(a) Nelg = 130788
Seyferts
(b) Nseyfert = 4059
EW(Hδ) > 5Å
(c) NEW Hδ = 39132 0.5 1.0 1.5 2.0 2.5 3.0 u−r (corrected)
SF
(d) Nsf = 93920
LINERs
(e) Nliner = 8091
SPOGs*
(f) Nspog = 857
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! !
The molecular outflow seen in NGC 1266 is about 110 M⊙ yr-1, far too large to drive with its star formation rate (dM/dt/SFR ~ 100)
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ALMA observations have shown that star formation is suppressed currently by a factor of 70
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A radio duty cycle might explain how NGC 1266 has come to be (and provide a look at how AGNs are able to remain obscured.)
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NGC 1266 is a shocked poststarburst galaxy (spog)
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WISE+SDSS is a great tracer of transitioning galaxies
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The SPOGs survey seems to have found what it was looking for (transitioning objects)…