Galaxy-Scale AGN Outflows: Two Puzzles, Two Solutions Claude-Andr - PowerPoint PPT Presentation

Galaxy-Scale AGN Outflows: Two Puzzles, Two Solutions Claude-André Faucher-Giguère UC Berkeley Miller Institute for Basic Research in Science with Eliot Quataert & Norm Murray

The possible roles of AGN feedback Establish correlations between Truncate star formation SMBH and galaxy properties Salim+07 Gultekin+09 Models that assume f ~5% L AGN couples to ISM are successful in explaining in these observations

Observational breakthroughs on AGN outflows Mrk 231 • km/s Massive, galaxy-scale AGN outflows in local ULIRGs ➡ neutral, ionized, CO, OH, HCN, ... Rupke & Veilleux 11 • Herschel, E-VLA, ALMA, ... to kpc CO revolutionize this field 0.03 0.02 • 0.01 Physical conditions in QSO outflows using low-ion BALs ( ⇒ energetics) 0 Feruglio+10 -1000 -500 0 500 1000 Velocity [Km/s]

Physical conditions in luminous QSO atomic outflows • Photoionization modeling particularly constraining in QSOs with FeII* broad line absorption ( T ~10 4 K, v ~5,000 km/s; FeLoBALs): SDSS J0318-0600 n e ~ 10 4 cm -3 Δ R ~0.01 pc (absorber thickness) N H ~ 10 20-21 cm -2 R~ 1-3 kpc (distance from SMBH) ionization param Dunn+10 Observations from Moe+09, Dunn+10, Bautista+10, Arav 10

Physical conditions in luminous QSO atomic outflows • Photoionization modeling particularly constraining in QSOs with FeII* broad line absorption ( T ~10 4 K, v ~5,000 km/s; FeLoBALs): n e ~ 10 4 cm -3 Δ R ~0.01 pc (absorber thickness) N H ~ 10 20-21 cm -2 R~ 1-3 kpc (distance from SMBH) ionization param Observations from Moe+09, Dunn+10, Bautista+10, Arav 10

Physical conditions in luminous QSO atomic outflows • Photoionization modeling particularly constraining in QSOs with FeII* broad line absorption ( T ~10 4 K, v ~5,000 km/s; FeLoBALs): ⇒ Δ R/R ~10 -5 n e ~ 10 4 cm -3 Jupiter mass! Δ R ~0.01 pc (absorber thickness) N H ~ 10 20-21 cm -2 R~ 1-3 kpc (distance from SMBH) ionization param Observations from Moe+09, Dunn+10, Bautista+10, Arav 10

Physical conditions in luminous QSO atomic outflows • Photoionization modeling particularly constraining in QSOs with FeII* broad line absorption ( T ~10 4 K, v ~5,000 km/s; FeLoBALs): ⇒ Δ R/R ~10 -5 n e ~ 10 4 cm -3 Jupiter mass! Δ R ~0.01 pc (absorber thickness) N H ~ 10 20-21 cm -2 R~ 1-3 kpc (distance from SMBH) ionization param 1. What are these things? 2. How can we use them to measure outflow energetics? Observations from Moe+09, Dunn+10, Bautista+10, Arav 10

Compact absorbers must form in situ, at R ~kpc from SMBHs • If they traveled from the SMBH to their implied location... ◆ − 1 ✓ ◆ ✓ t flow ≈ R R v v ≈ 3 × 10 5 yr 10 , 000 km s − 1 3 kpc • But destroyed by hydro instabilities and thermal evaporation in t KH , t evap ∼ few × 10 3 yr Not a direct accretion disk wind! CAFG, Quataert, & Murray 12

Radiative shock model • Form in interaction of the QSO blast wave with an ISM clump: v sh v sh v sh T sh ~ v sh 2 T sh ~ v sh 2 n H c,i , T c i v sh,c a n H c,f , T c f n H pre , T pre Shock wave propagates in cloud on At t>t KH , t drag , original cloud is shredded QSO blast wave encounters moderately crushing time t cc , cloud is destroyed into cloudlets traveling at ~v sh and cloud crushing by QSO dense ISM cloud. by K-H in t KH ~20t cc , and is accelerated compressed by hot post-shock gas. absorption by transient, to ~v sh in t drag . blast, accel by ram pre-existing ISM cloud compressed shreds pressure CAFG, Quataert, & Murray 12

Radiative shock model • Form in interaction of the QSO blast wave with an ISM clump: v sh v sh v sh T sh ~ v sh 2 T sh ~ v sh 2 n H c,i , T c i v sh,c a n H c,f , T c f n H pre , T pre Shock wave propagates in cloud on At t>t KH , t drag , original cloud is shredded QSO blast wave encounters moderately crushing time t cc , cloud is destroyed into cloudlets traveling at ~v sh and cloud crushing by QSO dense ISM cloud. by K-H in t KH ~20t cc , and is accelerated compressed by hot post-shock gas. absorption by transient, to ~v sh in t drag . blast, accel by ram pre-existing ISM cloud compressed shreds pressure CAFG, Quataert, & Murray 12

Radiative shock model • Form in interaction of the QSO blast wave with an ISM clump: v sh v sh v sh T sh ~ v sh 2 T sh ~ v sh 2 n H c,i , T c i v sh,c a n H c,f , T c f n H pre , T pre Shock wave propagates in cloud on At t>t KH , t drag , original cloud is shredded QSO blast wave encounters moderately crushing time t cc , cloud is destroyed into cloudlets traveling at ~v sh and cloud crushing by QSO dense ISM cloud. by K-H in t KH ~20t cc , and is accelerated compressed by hot post-shock gas. absorption by transient, to ~v sh in t drag . blast, accel by ram pre-existing ISM cloud compressed shreds pressure CAFG, Quataert, & Murray 12

Cloud crushing by shocks, Kelvin-Helmholtz instability • Well-studied problem for SNRs (e.g., Klein+94, Cooper+09) CAFG, Quataert, & Murray 12

Requirements for radiative shocks explain properties of cool absorbers • Acceleration, cold gas: ◆ 4 . 2 ✓ t drag < t KH v sh N H & 10 20 cm − 2 ⇒ t cool < t cc 5 , 000 km s − 1 • Post-shock compression: ✓ T sh ◆ ∼ 10 4 cm − 3 ≈ 4 n pre n BAL 10 4 K H H ⇒ ∆ R ∼ N H /n H ∼ 0 . 01 pc • Also: super-thermal line widths, multiple v components, reddening, ... CAFG, Quataert, & Murray 12

Energetics of QSO outflows • Outflows are multiphase n H pre • Most of kinetic power in hot flow: shocked ambient medium shocked ˙ M hot = 8 π Ω hot RN hot wind H µm p v hot v in FeLoBAL hot * QSO flow cool • Using radiative shock model: clumps ˙ E k ≈ 2 − 5% L AGN R sw ˙ M ≈ 1 , 000 − 2 , 000 M � / yr R c R s ˙ P ≈ 2 − 10 L AGN /c Observations from Moe+09, Dunn+10, Bautista+10, Arav 10 CAFG, Quataert, & Murray 12

The puzzle of large momentum fluxes • If all photons scatter once & P is conserved, ˙ P ∼ L AGN /c • Observations indicate ˙ P ∼ 10 L AGN /c • Simulations also require ULIRG data from Sturm+10 ˙ P � L AGN /c to reproduce M ● - σ (DeBuhr+) CAFG & Quataert, in prep.

Momentum driving forward shock t cool ≪ t flow with ambient medium No thermal pressure shocked reverse shock ambient in nuclear wind medium P final ~ P start shocked wind v in e.g., AGB wind Does this * QSO cool? Energy driving t cool ≫ t flow R sw Shocked gas does work R c P final ≫ P start R s e.g., Sedov-Taylor SNR CAFG & Quataert, in prep.

Proposal: AGN outflows are energy-driven • Possible in ULIRGs despite extreme densities ➡ relevant criterion is cooling of reverse shock: T sw ~10 10 K for v in ~0.1c ➡ 2-T plasma inhibits IC cooling AGN shocked wind cooling example cooling cooling p + time 1- T time 2- T e - t (yr) CAFG & Quataert, in prep.

Energy conservation naturally explains measured AGN momentum boosts • Predicts v in = 0 . 1 c ˙ P ✓ nuclear wind speed ◆ L AGN /c ∼ 1 2 galaxy wind speed E cons. • To be tested soon with Herschel, E-VLA, ALMA, ... P cons. (1 scatt limit) • galaxy wind speed (km/s) Analytic model will inform numerical implementations CAFG & Quataert, in prep.

Robust to mixing, leakage • Stellar wind bubbles smaller & slower than in energy-conserving Carina nebula models (Castor) ➡ cooling due to mixing (McKee+84) ➡ hot gas vents out (H.-C. & Murray 09) • AGN winds more robust ➡ ~30 × wind mass of cool gas before catastrophic ff cooling Smith & Brooks 07 ➡ escape along paths <10 -3 under- dense can still boost P by factor >10 in ULIRGs CAFG & Quataert, in prep.

Summary • Compact, cool absorbers form in radiative shocks • Energetics in good agreement with M ● - σ requirements • Observations of galaxy-scale AGN outflows suggest ˙ P � L AGN /c • Proposal: outflows are energy-conserving • Prediction: ˙ ✓ nuclear wind speed ◆ P L AGN /c ∼ 1 2 galaxy wind speed