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 H2 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. 2005 ●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 1996. )●Dependence of FR I/II divide on host galaxy luminosity●ISM pressure.

Spitzer Surveys of 3C Sources

IRLum.

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.

H2 Emission from 3C 326

●Spitzer IRS spectra dominated by pure-rotational H2 lines: L(H2)/LIR=0.15 !!

(Ogle et al. 2007b, ApJ, submitted)

●Spitzer IRAC images show tidal bridge/tail. ●Northern galaxy is extreme H2 emitter.

●3C 326 is 2nd 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(H2)=125,400,1000 K

●M(H2)=1.1E9 Msun

●Ortho/Para H2=2.1-3.0

Ogle et al. 2007b

●L(H2)=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(H2)=6E41 erg/s,●L(178 MHz)=1E41 erg/s●M(H2 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 H2

25% of FR Is have strong H2! 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 IIsIncluding 3C 326, 3C 293 (Ogle et al. 2007c)

MOHEG's: L(H2) >1E40 erg/sL(H2)/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 H2 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 H2. ●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 H2 lines—kinematics.

DESPARATELY NEEDED:●High spatial-resolution imaging (VLBI) of radio cores.●AGN X-ray fluxes (Chandra).●CO observations to estimate cold H2 mass.

●THEORY! Can jets heat 1E9 Msun of H2 to 1000 K??

COMING SOON: