The Rela(on Between Bars and AGN locally and at high redshi8

Transcription

1 The Rela(on Between Bars and AGN locally and at high redshi8 Mauricio Cisternas Ins(tuto de Astrofisica de Canarias The Triggering Mechanisms for AGN, Leiden, July 24, 2013

2 What is triggering most AGN? o Major galaxy mergers? YES NO Recent/ongoing interac(ons in a minority (~15-25%) of AGN hosts Merging frac(on consistent with inac(ve galaxies Significant frac(on of disk- dominated hosts out to z~1 and even z~2 (e.g.: Gabor+09; Georgakakis+09; Jahnke+09; Cisternas+11a,b; Schawinski+11; Kocevski+12) o AGN in disks: how are they being fed? COSMOS AGN at z~0.6, HST/ACS

3 Black hole growth in disks: feeding o Stellar bars can drive ISM toward central regions, s(mulate nuclear star forma(on could bars also feed a BH? o Can a kpc structure be responsible for what happens in sub pc scales? o Should we expect to see a bar- AGN connec(on? AGN ac(vity short lived (~ Myr), but bars are long lived (e.g., Berentzen+07, Kraljic+12, Athanassoula+13) Mar(ni et al. (2003) NGC 4639 Seyfert 1

4 Aiemp(ng to connect bars and AGN o Many (local) studies on the bar- AGN connec(on frac(on of barred and unbarred ac(ve galaxies frac(on of ac(ve and inac(ve barred galaxies o Summary of local results: Do AGN prefer barred galaxies? Yes they do! Arsenault+89 Knapen+00 Laine+02 Maia+03 Laurikainen+04a Coelho&Gadom11 Oh+12 Not more than inac4ve galaxies Moles+95 McLeod&Rieke95 Mulchaney&Regan97 Ho+97 Hunt&Malkan99 Lee+12 No, they avoid barred galaxies Shlosman+00 Zhang+09

5 Bar frac(on The rela(on between bars and AGN: beyond z=0 Silverman+08 Sheth+08 Redshi8

6 The rela(on between bars and AGN: beyond z=0 Summary of observa(onal results:

7 Bar- AGN connec(on out to z=0.8 o Data: COSMOS Survey 2 deg 2 mul(wavelength survey HST/ACS (F814W) 35+ photometric bands coverage from X- ray to radio o Sheth+08 Sample: L* & brighter spirals M V < to M V < (from z=0 to z=0.9) z<0.84 avoid SDSS u- band rejects ellip(cals, compact objects, merging systems, highly inclined disks Total sample of 2157 objects Bar detec(on: Ellip(city/PA and visually z=0.3 z=0.6 z=0.4 z=0.7

8 Bar- AGN connec(on out to z=0.8 AGN catalog of choice: Chandra- COSMOS Only central 0.9 deg 2 observed Flux limit: sensi(vity 3- (mes below XMM- COSMOS C- and XMM- COSMOS areas Op(cal/NIR iden(fica(on of X- ray sources (Civano+12) 76 galaxies from Sheth+08 have an C- COSMOS X- ray counterpart

9 Bar- AGN connec(on out to z=0.8 o Cau(on on using catalogs blindly! o Example: Op(cal counterpart to bright X- ray source (L X = erg/s) - Barred galaxy - > bar- driven AGN? - Interac(on- induced bars and AGN? - Actual X- ray source: background QSO? background QSO? interac(ng pair?

10 Bar- AGN connec(on out to z=0.8 Bar frac(on: o Dependent on stellar mass o Par(cularly at high- z Stellar mass- matched samples: Sheth log(m * ) z= z= z=

11 Bar- AGN connec(on out to z=0.8 Bar frac4ons: Cisternas+ in prep o High- z: no difference o Low- z: AGN show mild enhancement o Raw version: no L X cut

12 Bar- AGN connec(on out to z=0.8 Evolu(on of AGN bar frac(on follows evolu(on of inac(ve barred galaxies At high- z (and high- L x ): no difference in bar frac(on: Bars not relevant for these AGN? Luminous AGN fueling in disks occurs before the assembly of the Hubble sequence, perhaps in dynamically hot disks? log(l X )=43.5 log(l X )=43.6 log(l X )=43.4 log(l X )=43.6 At low- z (and low- L x ): minor enhancement in AGN bar frac(on: Bars becoming important below a luminosity threshold? log(l X )=44.1 log(l X )=43.5

13 Revisi(ng the local bar- AGN affair o Local universe: not as exci(ng as at high- z but definitely not quiescent o ~40% of nearby galaxies show nuclear ac(vity (Ho 08)

14 Revisi(ng the local bar- AGN affair o Local universe: not as exci(ng as at high- z but definitely not quiescent o ~40% of nearby galaxies show nuclear ac(vity (Ho 08) o >60% of nearby spirals are barred (Eskridge+00)

15 Revisi(ng the local bar- AGN affair o Local universe: not as exci(ng as at high- z but definitely not quiescent o ~40% of nearby galaxies show nuclear ac(vity (Ho 08) o >60% of nearby spirals are barred (Eskridge+00) o No clear evidence for a local bar- AGN connec(on o Usual approach: bar frac(ons of ac(ve/inac(ve galaxies, but: AGN ac(vity: six orders of magnitude in luminosity and BH accre(on rate Stellar bars: there are bars and bars- Bar strength closely related to gas inflow rate Bar strength and degree of AGN ac(vity: not discrete but con4nuous

16 Near- IR and X- ray data o Spitzer Survey of Stellar Structure in Galaxies nearby (<40 Mpc) galaxies with IRAC 3.6um solid tracer of old stars - > stellar bars Parent sample of 144 barred galaxies Moderate inclina(ons; not disturbed or too faint, good Hubble type sampling Sheth+10 o Archival Chandra X- ray data Best tracer of low- luminosity AGN ac(vity No uniform survey of nearby galaxies Chandra archival data for ~20% of S 4 G galaxies For this study: 41 galaxies with ACIS data High resolu(on imaging: ~1 arcsec

17 X- ray Nuclear Morphologies Spitzer/IRAC 3.6um Chandra/ACIS Cisternas+13

18 By- product: BH growth in bulgeless galaxies Spitzer/IRAC 3.6um Chandra/ACIS kev

19 Quan(fying Nuclear Ac(vity o Hard X- ray luminosi(es (2-10 kev) if enough counts: spectral modeling otherwise, assump(ons on power law index o Eddington ra(os (L bol /L Edd ) proxy of accre(on rate BH masses: - direct measurements - M BH - σ * or M BH - L Bulge NGC2787 Cts/s/keV NGC Energy (kev) NGC4450 NGC 1291 Cts/s/keV NGC NGC

20 Quan(fying Bar Strength 1. Bar Structure (Kim, S 4 G in prep) 2D image decomposi(on of disk+bulge+bar ellip(city & boxiness o =1 b/a, 2. Gravita(onal torque (Diaz- Garcia, S 4 G in prep) ra(o of tangen(al to radial forces NGC 1367 NGC 1300 c c x y + =1, a b Athanassoula+90 Q T (r) = F T max (r) hf R (r)i, Combes & Sanders81 ε=0.5 c=2.7 Q=0.1 ε=0.8 c=3.2 Q=0.6

21 Bar strength vs nuclear ac(vity Q b ell x box boxiness ellipticity ρ= ρ= 0.1 ρ= ρ= ρ= ρ= ρ= ρ= 0.0 No posi(ve correla(ons In some cases, nega(ve trends Brighter or more efficient AGN: no preference for strong bars (strong inflows) Local low- luminosity AGN ac(vity: not closely connected to bar proper(es Low- luminosity AGN: no need for significant inflows to exist Cisternas+13 X-ray Luminosity Eddington ratio

22 Bars and AGN over cosmic (me: Summary AGN bar frac(on evolves in a similar fashion as the inac(ve bar frac(on over the last 7 billion years Luminous AGN in disks occur without the need of stellar bars Minor enhancement of ac(ve bar frac(on at lower- z/l x : Is there a sweet spot in L AGN - redshi8 space where bars maier? Nearby universe: extent of bar- driven inflow does not directly impact BH fueling Low- luminosity AGN ac(vity not related to large scale features - > LLAGN do not need bar- driven inflows