C+ As a Primary Coolant and Tracer of Star Formation

Dec 21st, 2012

SF

R

[CII]

Hea

tin

g

Cooling

de Looze et al. 2011

SF

R (

24 m

m +

FU

V)

ISO [CII]Herrera-Camus et al. 2013KINGFISH

PACS [CII]

~ 500 pc resolution

Sargsyan et al. 2012

[CII]/ LIR ~ const + SFR based on LIR SFR([CII])

Warm H T = 8000 Kn = 0.3 cm-3

Cold HT = 80 Kn = 30 cm-3Cold H2

T = 10 K

Classic PDR

Contributions to [CII] Line emission

OB star

H+

H+

H+

CNM

WNM

r ~ few pc

r ~ 10s pc

r~ 100s pc

C+/HI

C+/H2

FUV

Warm H+

T = 8000 K Ne = 5 cm-3

WIM

EUVr ~ 100s pc ?

[CII] a dominant coolant? Maybe

NO

NO

NO

YES!

Ionization: FUV, X-ray, C.R.Heating: P.E., C.R., X-ray/EUVCooling: [CII], [OI], Lya, e- recombination

nG = n2L

T

= n

T

Wolfire et al. (2003)

WNM stable

CNM

stableunstable

T = 7860 n = 0.35 cm-3 WNM

T = 85 n = 33 cm-3 CNM

Diffuse Gas Emission

= n

T158 mm

63 mm

Grain photoelectric

C II Cooling/H (CNM) > 10 CII Cooling/H (WNM)

PminPmax

** Note ** CNM in Thermal Balance:[CII] measures the total energy dumped into the gas.

Heating Rate = constn ZT [CII] = const

Wolfire et al. (2003)

Diffuse Gas Emission

Fraction of WNM/CNM ?

Dickey et al. 2009

CNM + WNM

CNM

[CNM + WNM]/CNM

Em

issi

on/L

Ab

sorp

tion

/LE

mis

sion

/Ab

sorp

tion

Heiles & Troland 2003: 60% WMN, 40% CNM locally in Galactic disk

Assume: 2/3 WNM, 1/3 CNM to outer galaxy

Mathis et al. 1982

Weingarter & Draine 2001 and

6eV

In diffuse ISM 10-20% of heating can come from PAH-

PAH + hn PAH+ + e-

PAH- + hn PAH + e-

2eV

Malloci et al. 2007

PDR Emission

Diffuse Gas

Classic PDRs

Orion PDR

[CII]

n

Kaufman et al. 1999 Kaufman et al. 1999

FU

V

FU

V

Heating Efficiency

G0/n = const

n

PDR Emission

Diffuse Gas

Classic PDRs

Orion PDR

n n

Kaufman et al. 1999 Kaufman et al. 1999

FU

V

FU

V

Heating Efficiency[OI]/[CII]

cr n[CII]

G0/n = const

Contribution from HII regionsTeff= 42000 K Abel et al 2005

Fraction of [CII]from HII region

Kaufman et al. 2006

Z=3Stellar association

Oberst et al. 2011

Carina Nebula

SPIFI[NII] 205 mm

ISO[CII]

30% [CII] diffuse ionised 70% [CII] neutral PDR

Oberst et al. 2006

Mookerjea et al. 2011 HerM33es

PACS [CII] [OI] M33 HII Region BCLMP 302

20-30% [CII] ionised gas80-70% [CII] neutral PDR

LMC-N 11B

Lebouteiller et al. 2012SHINING

5-15% [CII] diffuse ionised 95-85% [CII] neutral PDR

Bennett et al 1994, COBE FIRAS 7o beam Diffuse ionized gasWIM Emission

Wright et al. 1991 Line log L[C II] 158 mm 7.7[N II] 122 mm 6.9[N II] 205 mm 6.7[C I] 370 mm 5.5[C I] 610 mm 5.3

Bennett et al 1994, COBE FIRAS 7o beam

[CII]

[CII] from [NII]

[NII]

Diffuse ionized gas

Steiman-Cameron et al. 2010

Cygnus X

WIM Emission

What dominates the [CII] emission?

Galactic:WIM – Heiles 1994CNM – Bennett et al. 1994, Wolfire et al. 1995 GMC – Stacey et al. 1985; Shibai et al. 1991 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+/H2

Malhotra et al. 2001: Normal Galaxies - 50% WIM, PDRs G0 = 102 - 104.5, n = 102 - 104.5

Stacey et al. 2010

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

Aniano et al. 2012

Draine & Li 2007

NGC 6946 PACS 160 resolution

On the other hand……

~ 165 pc

Aniano et al. 2012

Low average U ~ 5, low fPDR < 20%

Wolfire, Hollenbach in prep: average U on GMCs ~10-30

Also Cubick et al. 2008, Pineda et al. 2010 found U < 100

Mechanical Heating?

Jenkins & Tripp 2011

Small Scale StructureTurbulent Dissipation in CNM

3800

Log normal fit + 0.05% 3x105 K cm-3

1)Warm diffuse cloud chemistry: CH+, HCO+

Godard et al. 2009, Falgarone et al. 2010

2)Tiny-Scale Atomic Structure (TSAS): HI absorption 10s AUe.g. Heiles 1997 (TSIS), (TSMS)

3)Warm diffuse H2 seen in emission Falgarone et al. 2005

Small Scale Structure (Continued)Turbulent Dissipation in CNM

4) High H2/PAH ratios seen in high latitude clouds. Ingalls et al. 2011

5)Warm H2 in MC surfaces (low UV field). Goldsmith et al. 2010, Habart et al. 2011

Habart et al. 2011

Spitzer H2 observationsModel Meudon PDR code

FUV field strength FUV field strength

L1721CaliforniaNGC 7023EHorseheadRho OphNGC 2023N

MHD shocks: Pineau des Forêts et al 1986

Shears: Joulain et al. 1998

TDRs – 100s AU:Godard et al. 2009

Turbulent Dissipation Region (TDR)

adiabatic cooling

de Looze et al. 2011

SF

R (

24 m

m +

FU

V)

ISO [CII]Herrera-Camus et al. 2013KINGFISH

PACS [CII]

~ 500 pc resolution

[CII]/ LIR ~ const + SFR based on LIR SFR([CII])

Sargsyan et al. 2012

extinction

opacity

cirrus

L(Ha) true +IMF +Starbust99 =SFR

Kennicutt et al. 2009

L(Pa) true +IMF +Starbust99 =SFR

Calzetti et al. 2007

Herrera-Camus et al. 2013

Low [CII]/IR seen in AGN, regions of normal galaxies, and ULIRGs.

1)Grain charging2)Dust optical depth at 158 mm3)Dusty HII regions4)High density

Low [CII]/24 mm points do not measure SFR

de Looze et al. 2011

SF

R (

24 m

m +

FU

V)

ISO [CII]Herrera-Camus et al. 2013KINGFISH

PACS [CII]

~ 500 pc resolution

[CII]/ LIR ~ const + SFR based on LIR SFR([CII])

Sargsyan et al. 2012

SF

R

[CII]

Hea

tin

g

Cooling

1)[CII] not dominated by high G0 - high n PDRs:[OI]/[CII] > 1 and lowheating efficiency

2)WIM/HII contribution is uncertain ~ 30%

3)[CII] mainly comes from low to moderate G0 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 mm)

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]/LIR