C + As a Primary Coolant and Tracer of Star Formation Dec 21 st, 2012

SFR [CII] Heating Cooling

de Looze et al SFR (24  m + FUV) ISO [CII] Herrera-Camus et al KINGFISH PACS [CII] ~ 500 pc resolution Sargsyan et al [CII]/ L IR ~ const + SFR based on L IR SFR([CII])

Warm H T = 8000 K n = 0.3 cm -3 Cold H T = 80 K n = 30 cm -3 Cold H 2 T = 10 K Classic PDR Contributions to [CII] Line emission OB star H+H+ H+H+ H+H+ CNM WNM r ~ few pc r ~ 10s pc r~ 100s pc C + /HI C + /H 2 FUV Warm H + T = 8000 K N e = 5 cm -3 WIM EUV r ~ 100s pc ? [CII] a dominant coolant? Maybe NO YES!

Ionization: FUV, X-ray, C.R. Heating: P.E., C.R., X-ray/EUV Cooling: [CII], [OI], Ly , e - recombination n  = n 2  T = nT Wolfire et al. (2003) WNM stable CNM stable unstable T = 7860 n = 0.35 cm -3 WNM T = 85 n = 33 cm -3 CNM Diffuse Gas Emission

= nT 158  m 63  m Grain photoelectric C II Cooling/H (CNM) > 10 CII Cooling/H (WNM) Pmin Pmax ** Note ** CNM in Thermal Balance: [CII] measures the total energy dumped into the gas. Heating Rate = const n Z T [CII] = const Wolfire et al. (2003) Diffuse Gas Emission

Fraction of WNM/CNM ? Dickey et al CNM + WNM CNM [ CNM + WNM]/CNM Emission/L Absorption/L Emission/Absorption Heiles & Troland 2003: 60% WMN, 40% CNM locally in Galactic disk Assume: 2/3 WNM, 1/3 CNM to outer galaxy

Mathis et al Weingarter & Draine 2001 and 6eV In diffuse ISM 10-20% of heating can come from PAH - PAH + h PAH + + e - PAH - + h PAH + e - 2eV Malloci et al. 2007

PDR Emission Diffuse Gas Classic PDRs Orion PDR [CII] n Kaufman et al FUV Heating Efficiency G 0 /n = const n

PDR Emission Diffuse Gas Classic PDRs Orion PDR n n Kaufman et al FUV Heating Efficiency [OI]/[CII] cr n [CII] G 0 /n = const

Contribution from HII regions Teff= KAbel et al 2005 Fraction of [CII] from HII region Kaufman et al Z=3 Stellar association

Oberst et al Carina Nebula SPIFI [NII] 205  m ISO [CII] 30% [CII] diffuse ionised 70% [CII] neutral PDR Oberst et al. 2006

Mookerjea et al HerM33es PACS [CII][OI]M33 HII Region BCLMP % [CII] ionised gas 80-70% [CII] neutral PDR

LMC-N 11B Lebouteiller et al SHINING 5-15% [CII] diffuse ionised 95-85% [CII] neutral PDR

Bennett et al 1994, COBE FIRAS 7 o beam Diffuse ionized gas WIM Emission Wright et al Line log L [C II] 158  m 7.7 [N II] 122  m 6.9 [N II] 205  m 6.7 [C I] 370  m 5.5 [C I] 610  m 5.3

Bennett et al 1994, COBE FIRAS 7 o beam [CII] [CII] from [NII] [NII] Diffuse ionized gas Steiman-Cameron et al Cygnus X WIM Emission

What dominates the [CII] emission? Galactic: WIM – Heiles 1994 CNM – Bennett et al. 1994, Wolfire et al GMC – Stacey et al. 1985; Shibai et al Cubick et al 2008 What is the [CII] Budget ? Beam size? galaxy type ? Metallicity ? Where ? Extragalactic: Cormier et al. 2012: Low Z galaxy Haro 11 – 10% PDR, 90% in diffuse ionized Madden et al. 1997: Low Z galaxy IC 10 – 10% WIM, 10% CNM, 80% PDR with C + /H 2 Malhotra et al. 2001: Normal Galaxies - 50% WIM, PDRs G 0 = , n =

Stacey et al [CII] and CO are excited by (nearby?) star formation

Aniano et al Draine & Li 2007 NGC 6946 PACS 160 resolution On the other hand…… ~ 165 pc

Aniano et al Low average U ~ 5, low f PDR < 20% Wolfire, Hollenbach in prep: average U on GMCs ~10-30 Also Cubick et al. 2008, Pineda et al found U < 100 Mechanical Heating?

Jenkins & Tripp 2011 Small Scale Structure Turbulent Dissipation in CNM 3800 Log normal fit % 3x10 5 K cm -3 1)Warm diffuse cloud chemistry: CH +, HCO + Godard et al. 2009, Falgarone et al )Tiny-Scale Atomic Structure (TSAS): HI absorption 10s AU e.g. Heiles 1997 (TSIS), (TSMS) 3)Warm diffuse H 2 seen in emission Falgarone et al. 2005

Small Scale Structure (Continued) Turbulent Dissipation in CNM 4) High H 2 /PAH ratios seen in high latitude clouds. Ingalls et al )Warm H 2 in MC surfaces (low UV field). Goldsmith et al. 2010, Habart et al Habart et al Spitzer H 2 observations Model Meudon PDR code FUV field strength L1721 California NGC 7023E Horsehead Rho Oph NGC 2023N

MHD shocks: Pineau des Forêts et al 1986 Shears: Joulain et al TDRs – 100s AU: Godard et al Turbulent Dissipation Region (TDR) adiabatic cooling

de Looze et al SFR (24  m + FUV) ISO [CII] Herrera-Camus et al KINGFISH PACS [CII] ~ 500 pc resolution [CII]/ L IR ~ const + SFR based on L IR SFR([CII]) Sargsyan et al. 2012

extinction opacity cirrus L(H  ) true + IMF + Starbust99 = SFR Kennicutt et al. 2009

L(P  ) true + IMF + Starbust99 = SFR Calzetti et al. 2007

Herrera-Camus et al Low [CII]/IR seen in AGN, regions of normal galaxies, and ULIRGs. 1)Grain charging 2)Dust optical depth at 158  m 3)Dusty HII regions 4)High density Low [CII]/24  m points do not measure SFR

de Looze et al SFR (24  m + FUV) ISO [CII] Herrera-Camus et al KINGFISH PACS [CII] ~ 500 pc resolution [CII]/ L IR ~ const + SFR based on L IR SFR([CII]) Sargsyan et al. 2012

SFR [CII] Heating Cooling 1)[CII] not dominated by high G 0 - high n PDRs: [OI]/[CII] > 1 and low heating efficiency 2)WIM/HII contribution is uncertain ~ 30% 3)[CII] mainly comes from low to moderate G 0 and moderate n PDRs plus some neutral diffuse gas (mainly in outer galaxy). Keeps CII/CO relation and [CII] as a dominant coolant. 5)Mechanical heating does not dominate due to correlation with radiative tracers (24  m) 4)Dust fits correct? [CII] comes mainly from low UV fields (everywhere in galaxy). [CII]/CO correlation? [OI] problem?

6)[CII] as SFR breaks down (or another calibration is needed – Sargsyan et al. 2012) for AGN and ULIRGs due to low [CII]/L IR