The Spitzer View of Jet-ISM Interactions Patrick Ogle Ski Antonucci, Phil Appleton, David Whysong, & Christian Leipski

Outline ● Molecular gas content of radio galaxies. ● Spitzer surveys of ISM in radio galaxies. – AGN dust emission. – PAH emission from star-forming regions. – Molecular hydrogen emission from shocks. ● Extreme H 2 emission from radio galaxies.

Jet-ISM Interactions NGC 4258: Spitzer, Chandra,VLA. ~3E39 erg/s in jet shocks. (Yang et al. 2007) 3C 293: 2.2 µm, 1.5 GHz, CO. Possible jet/CO interaction. (A. Evans et al. 1999)

Molecular Gas Content of Radio Galaxies 25% of IR-bright z<0.2 RGs detected in CO (A. Evans et al. 2005).

Radio Galaxies with Strong CO Evans et al ● morphological peculiarities ● stellar or dust disks ● collision/merger activity (Heckman 1986)

Radio Morphology Compact sources (Labiano, O'Dea...) HYMORS Radio jet decollimation (Gopal- Krishna 2000)

The FRI/II Divide (Owen & Ledlow 1994, Bicknell ) ● Dependence of FR I/II divide on host galaxy luminosity ● ISM pressure.

Spitzer Surveys of 3C Sources IR Lum. Radio Luminosity Ogle et al. 2006

IR-Luminous vs. IR-weak FR IIs Keck LWS 12 µm images (D. Whysong).

Spitzer IR Spectra of Radio Galaxies FR I Radio Galaxies. (Ogle et al. 2007a) ● AGNs: Silicate emission, high-ion lines. ● Starburst activity: polycyclic aromatic hydrocarbon features.

H 2 Emission from 3C 326 ● Spitzer IRS spectra dominated by pure-rotational H 2 lines: L(H 2 )/LIR=0.15 !! (Ogle et al. 2007b, ApJ, submitted) ● Spitzer IRAC images show tidal bridge/tail. ● Northern galaxy is extreme H 2 emitter. ● 3C 326 is 2 nd largest known FRII (1.9 Mpc diameter).

3C 326 SED ● Stellar emission J, H, and K bands. ● Mid-IR dust emission from weak star-formation (2E-2 Msun/yr). ● Radio cores and lobes

H2 Shock-Excitation in 3C 326 ● T(H 2 )=125,400,1000 K ● M(H 2 )=1.1E9 Msun ● Ortho/Para H 2 = Ogle et al. 2007b ● L(H 2 )=8E41 erg/s L(jet kinetic) ~ 1E44 erg/s, mostly dissipated in Mpc- scale lobes. L(grav. inflow) ~ 3E42 erg/s from 12 Msun/yr

Shocked H2 Emission in 3C 293 ● L(H 2 )=6E41 erg/s, ● L(178 MHz)=1E41 erg/s ● M(H 2 warm, cold)=1E9, 1.5E10 Msun ● HI and ionized outflows (Morganti et al. 03,05) Spitzer IRAC and IRS Ogle et al. 2007c

More Radio Galaxies with strong H 2 25% of FR Is have strong H 2 ! 6% of FR IIs. (Ogle et al. 2007c)

Molecular Hydrogen Emission Galaxies ● Stephan's Quintet intergalactic shock (Appleton et al. 2006). ● Zw 3146 X-ray cluster cD (Egami et al. 2006). ● 5 FR Is, 3 FR IIs Including 3C 326, 3C 293 (Ogle et al. 2007c) MOHEG's: L(H 2 ) >1E40 erg/s L(H 2 )/L(IR)>1E-3

MOHEGs—Gas Rich Mergers? 3C 84, 293, 310 3C 315, 317, 326 3C 338, 386, 433 HST WFPC2 snapshots (PI Sparks)

What Powers the H 2 Emission? ● AGN X-rays -In most cases the AGN is not powerful enough. Chandra data needed!! ● Radio Jet ---jet powers are large enough, but also require: a) Large dissipation in host ISM, affecting morphology. b) Large energy conversion efficiency to heat H 2. ● Tidally-induced Accretion from a Companion a) Companions and interaction/mergers prevalent. b) Gravitational potential energy abundant. c) Problem(?)—shocks must be non-dissociative d) Why is the phenomenon so common in RGs (?)

Future Directions ● Ground-based imaging of near-IR rovibrational lines. ● Spitzer IRS High-Resolution spectra of H 2 lines—kinematics. DESPARATELY NEEDED: ● High spatial-resolution imaging (VLBI) of radio cores. ● AGN X-ray fluxes (Chandra). ● CO observations to estimate cold H 2 mass. ● THEORY! Can jets heat 1E9 Msun of H 2 to 1000 K?? COMING SOON: