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, 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

NGC 1266 HST B V I NGC 1266 appears to be a “quiescent” S0 ! NGC 1266 hosts a massive molecular disk (>10 9 M ⊙ ) and a massive (>10 8 M ⊙ ) molecular outflow that is multiphase being driven by an AGN ! A young (1/2 Gyr) stellar population outside the nucleus is the most recent (obvious) SF event ! Star formation is suppressed by at least a factor of 70 seen in the nucleus Alatalo et al. 2011 Alatalo et al. 2011, Davis et al. 2012, Nyland et al. 2013, Alatalo et al. 2014a, 2014b (submitted)

NGC 1266 HST B V I NGC 1266 appears to be a “quiescent” S0 ! NGC 1266 hosts a massive molecular disk (>10 9 M ⊙ ) and a massive (>10 8 M ⊙ ) molecular outflow that is multiphase being driven by an AGN ! A young (1/2 Gyr) stellar population outside the nucleus is the most recent (obvious) SF event ! Star formation is suppressed by at least a factor of 70 seen in the nucleus Alatalo et al. 2011 Alatalo et al. 2011, Davis et al. 2012, Nyland et al. 2013, Alatalo et al. 2014a, 2014b (submitted)

NGC 1266 contains massive molecular outflow B B-Y 20’’ 25’ 40’’ 26’ 00’’ M gas ~ 4 × 10 9 M ⊙ (Young et al. 2011) 03h 16m 2.5s 1.5s M outflow ~ few × 10 8 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)

NGC 1266 contains massive molecular outflow B B-Y 20’’ 25’ 40’’ 1.0 CO(2-1) 26’ 00’’ 0.8 0.6 M gas ~ 4 × 10 9 M ⊙ (Young et al. 2011) T mb (K) 03h 16m 2.5s 1.5s 0.4 M outflow ~ few × 10 8 M ⊙ 0.2 (Alatalo et al. 2011, new HCN and CS(2-1) have wings) Outflow mass flux ~ 110 M ⊙ yr -1 0.0 Outflow dynamical time < 3 Myr (Alatalo et al. 2011) 1600 1800 2000 2200 2400 2600 2800 Velocity (km s -1 )

NGC 1266 is a poststarburst galaxy NUV: tracing ~1/2 Gyr stellar population NUV imaging show a larger 25’’ distribution of young stars than the current site of the molecular gas ! 2 kpc 35’’ A stellar population analysis shows that the population is 200 pc poststarburst of age (~500 Myr) with mass fraction ~10% 45’’ ! Alatalo et al. 2014a Current site of all molecular gas (from CO) -02o 25’ 55’’ 03h 16m 1.8s 1.4s 1.0s

SF+AGN in the SED 10 11 Keck HST 2MASS 10 10 IRAC MIPS PACS SPIRE ALMA VLA 10 9 • ) Luminosity (L O 10 8 10 7 Full Model 10 6 Stellar AGN Cold Dust Spitzer IRS Synchrotron 10 5 Free Free 10 4 10 -1 10 0 10 1 10 2 10 3 10 4 10 5 10 6 Wavelength ( µ m) 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 . L TIR ≈ 3 × 10 10 L ⊙ (1.2 × 10 44 ergs s -1 ) Alatalo et al. 2014b, submitted

Extreme SF suppression Milky Way 1 Normal Galaxies 2 LIRGS 2 Last burst of SF happened Normal Galaxies 3 Bulges 3 ~500Myr ago and the nuclear ULIRGs 4 High-z galaxies 5 molecular gas has remained Radio galaxies 6 2 0 1 / 1 since then ! 0 0 • yr -1 kpc -2 ) SFR calculated using the free- 1 / 1 free emission indicates a SFR of >0.9 M ⊙ yr -1 (the ALMA 1266 0 log( � SFR ) (M O decomposed data agree) ! Σ gas ≈ 10 4 M ⊙ pc -2 (from CO, CS and HCN) ! -2 Using dense gas (CS) size and assuming SF/CS co- spatiality, NGC 1266 is a factor of ~70 off the K-S relation. -4 0 1 2 3 4 5 • pc -2 ) log( � mol ) (M O Alatalo et al. 2014b submitted

A scenario to explain NGC 1266 Alatalo et al. 2014a, 2014b (submitted)

A scenario to explain NGC 1266 1. Minor merger causes the collapse of a subcritical molecular disk in the already mostly old NGC 1266 Alatalo et al. 2014a, 2014b (submitted)

A scenario to explain NGC 1266 2. Gas collapses inward 1. Minor merger causes the toward nucleus, and young collapse of a subcritical stars (10% M bulge ) are formed molecular disk in the already within the 2kpc boundary mostly old NGC 1266 Alatalo et al. 2014a, 2014b (submitted)

A scenario to explain NGC 1266 2. Gas collapses inward 1. Minor merger causes the toward nucleus, and young collapse of a subcritical stars (10% M bulge ) are formed 3. Population ages, gas molecular disk in the already within the 2kpc boundary continues toward the AGN mostly old NGC 1266 Alatalo et al. 2014a, 2014b (submitted)

A scenario to explain NGC 1266 2. Gas collapses inward 1. Minor merger causes the toward nucleus, and young collapse of a subcritical stars (10% M bulge ) are formed 3. Population ages, gas molecular disk in the already within the 2kpc boundary continues toward the AGN mostly old NGC 1266 4. AGN radio jet ignites, injecting turbulence into the dense molecular disk, suppressing SF (x70) and driving an outflow Alatalo et al. 2014a, 2014b (submitted)

A scenario to explain NGC 1266 2. Gas collapses inward 1. Minor merger causes the toward nucleus, and young collapse of a subcritical stars (10% M bulge ) are formed 3. Population ages, gas molecular disk in the already within the 2kpc boundary continues toward the AGN mostly old NGC 1266 5. AGN stops being fueled, 4. AGN radio jet ignites, radio turns off, and outflow injecting turbulence into the begins falling back onto the dense molecular disk, nucleus. Turbulence suppressing SF (x70) and dissipates. driving an outflow Alatalo et al. 2014a, 2014b (submitted)

A scenario to explain NGC 1266 2. Gas collapses inward 1. Minor merger causes the toward nucleus, and young collapse of a subcritical stars (10% M bulge ) are formed 3. Population ages, gas molecular disk in the already within the 2kpc boundary continues toward the AGN mostly old NGC 1266 6. Gas re-ignites radio jet? Duty cycle? 5. AGN stops being fueled, 4. AGN radio jet ignites, radio turns off, and outflow injecting turbulence into the begins falling back onto the dense molecular disk, nucleus. Turbulence suppressing SF (x70) and dissipates. driving an outflow Alatalo et al. 2014a, 2014b (submitted)

we need a systematic search for these sorts of objects. Case studies are great, but can’t tell us about a population. ! What is the duty cycle of the SF quenching? ! What evolutionary pictures lead to an AGN expulsion of molecular gas? ! Can we begin to understand NGC 1266-like objects? ! What is the redshift evolution of these objects?

Finding the needle in the haystack NGC 1266 hosts an AGN-driven UV outflow, but also contains a unique 25’’ set of optical features 35’’ 45’’ 10 ″ -02o 25’ 55’’ 03h 16m 1.8s 1.4s 1.0s young(ish) stellar population 
 Alatalo et al. 2014a shocked ionized gas (Davis et al 2012)


 
 shocked ionized gas ratios + poststarburst stellar population 
 = 
 a Shocked Poststarburst Galaxy (spog) ! ! ! ! NGC 1266 is a spog.

SPOGS: First results 3.0 ELG EW(H δ ) > 5 Å Parent Seyferts 2.5 u-r (corrected) 2.0 1.5 1.0 N parent = 130788 (a) N seyfert = 4765 (b) N EW H δ = 46936 (c) 0.5 SF LINERs SPOGS N sf = 111972 (d) N liner = 11327 (e) N spog = 1067 (f) 9.0 9.5 10.0 10.5 11.0 11.5 Alatalo et al. 2014c (submitted) log( M gal ) [ M O • ]

SPOGS result: a surprise a WISE infrared transition zone when in doubt, cross-correlate with WISE GZ sample from Schawinski et al. 2014; Alatalo et al. 2014c (submitted)

SPOGS result: a surprise a WISE infrared transition zone 3.0 LTGs 4 ETGs WISE [4.6]-[12] (Vega) 2.5 u-r (corrected) 3 2.0 2 1.5 1 1.0 (a) (b) 0.5 0 9.0 9.5 10.0 10.5 11.0 11.5 9.0 9.5 10.0 10.5 11.0 when in doubt, cross-correlate with WISE log( M gal ) [ M O • ] log( M gal ) [ M O • ] 0.3 4 WISE [3.4]-[4.6] (Vega) WISE [4.6]-[12] (Vega) 0.2 3 0.1 2 0.0 1 -0.1 (c) -0.2 0 0 1 2 3 4 0.5 1.0 1.5 2.0 2.5 3.0 WISE [4.6]-[12] (Vega) u-r (corrected) GZ sample from Schawinski et al. 2014; Alatalo et al. 2014c (submitted)

SPOGS* colors u-r and W2-W3 transformation sequence EW(H δ ) > 5 Å ELG Seyferts 4 [4.6] − [12] (Vega) 3 2 1 N elg = 130788 (a) N seyfert = 4059 (b) N EW H δ = 39132 (c) 0 SF LINERs SPOGs* N sf = 93920 (d) N liner = 8091 (e) N spog = 857 (f) 0.5 1.0 1.5 2.0 2.5 3.0 Alatalo et al. 2014c (submitted) u − r (corrected)


 
 
 
 
 
 The end. ! 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) ! ALMA observations have shown that star formation is suppressed currently by a factor of 70 ! 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.) ! NGC 1266 is a shocked poststarburst galaxy (spog) ! ! WISE+SDSS is a great tracer of transitioning galaxies ! ! The SPOGs survey seems to have found what it was looking for (transitioning objects)… questions?