1. The Irradiated and Stirred ISM of Active Galaxies Marco Spaans, Rowin Meijerink (Leiden), Frank Israel (Leiden), Edo Loenen (Leiden), Willem Baan (ASTRON), Dominik Schleicher (Leiden/ESO), Ralf Klessen (Heidelberg) Juan Pablo Perez Beaupuits (Groningen)

2. n Concentrate on irradiated turbulent gas in star-forming regions and close to AGN n How star formation and AGN affect the ISM: M82 – Arp220 – Mrk231 and produces lines: What SF aspects lead to what FIR response

3. PDRs: 6 < E < 13.6 eV n Heating: Photo-electric emission from grains and cosmic rays n Cooling: Fine-structure lines like [OI] 63, 145; [CII] 158 μm and emission by H 2, CO, H 2 O n 10 eV photon penetrates 0.5 mag of dust

4. XDRs: E > 1 keV n Heating: X-ray photo-ionization --> fast electrons; H and H 2 vib excitation; UV emission (Ly α, Lyman-Werner) n Cooling: [FeII] 1.26, 1.64; [OI] 63; [CII] 158; [SiII] 35 μm; thermal H 2 vib; gas-dust n 1 keV photon penetrates 10 22 cm -2 of N H

5. n PDR (left) with n=10 5 cm -3 and G=10 3.5 n XDR with n=10 5 cm -3 and F X = 5.1 erg s -1 cm -3 n Note N H dependence H 2, C +, C, CO, OH, H 2 O: FIR lines of species trace different regions

6. A comment on AGN: Relative Size PDR/XDR n 10 7 M ๏ BH at 3% Eddington forh G 0 =10 and 1-100 keV powerlaw of slope -1 (with 10% L)

7. MDRs: how about kinetics? n Mechanically Dominated Regions n Turbulent dissipation heats the gas, which leads to IR emission n UV only heats cloud surface n Cosmic rays also heat deep inside cloud, but strongly affect HCO + n E.g., at T>100K: HNC + H  HCN + H

8. Sources of Turbulence n YSOs n SNe n Sloshing motions (accretion) n Assume 1-10% efficiency through a turbulent cascade -> mechanical heating competes with normal CR heating for SF rates of 10 – 100 M o /yr

9. g n E.g., P cygni profiles in Arp220: 100 km/s outflow ( 100 pc scale )

10. changes in high density tracers  temperature increases  E.g., HNC, HCN, HCO + affected normal mechanical

11. Sample of ULIRGs n combined PV, SEST and literature –low density gas: CO(1-0) & CO(2-1) –high density gas: HCN(1-0), HNC(1-0), HCO + (1-0), CN(1-0), CN(2-1), CS(3-2) n total of 117 sources, but incomplete: –110 CO(1-0), but 32 CO(2-1) –84 HCN –only 33 have HCN, HNC and HCO + n Note: single dish, so integrated properties

12. Relation with L FIR n relation L FIR – L molecule reflects Kennicutt-Schmidt laws: Σ SFR ~ Σ gas α, α=1.4 n Krumholz & Thompson (2007): –if n crit < n ave : α ≈ 1.5 (KS law) –if n crit > n ave : α ≤ 1 –Note: slope in fits = 1/α

13. A few fits 2e3 1e4 3e6 2e5 4e5 2e7 1e6 CO(1-0) α ~ 1.4 CO(2-1) closer to 1 Others α ≤ 1; black squares OH-MM

14. Relation with L FIR n Kennicutt-Schmidt laws: Σ SFR ~ Σ gas α, α=1.4 n Krumholtz & Thompson (2007): –if n crit < n ave : α ≈ 1.5 (K-S law) –if n crit > n ave : α ≤ 1 –Note: slope in fits = 1/α n Our data follow the K&T predictions, but can we learn more?

15. Toy model: starburst that decays; deplete dense gas and go from SF -> SNe

16. For some ULIRGs, dense gas tracers that correlate with IR may trace more SN than UV exposure, see Loenen et al. (2008)

17. Lowering the metallicity to 1% Zo: CO no longer dominant molecular gas coolant

18. Summary n In addition to fine structure lines, CO, HCN, HNC, HCO + lines are good diagnostics to get to SF properties n Turbulence (and cosmic rays) matter!

19. so IR response of the ISM may not be tracing star formation directly; [CII] en [CI] lines probe this directly

20. n How about CRs? n PDR model with CR rate = 5x10 -15 s -1 ; so SN rate for ~100 M 0 /yr n Note small changes in C, OH and H 2 O

21. In fact, CRs can dominate the thermodynamics of molecular gas for star formation rates > 100 Mo/yr; think of Arp220