Der Paul van der Werf Leiden Observatory Radiative and mechanical feedback in the molecular gas in (U)LIRGs London September 16, 2011

Paul van der Werf

Leiden Observatory

Radiative and mechanical feedback in the molecular gas in (U)LIRGs

LondonSeptember 16, 2011

Credits

Kate Isaak (ESTEC)Padelis Papadopoulos (MPI für Radioastronomie)Marco Spaans (Kapteyn Astronomical Institute)Eduardo González-Alfonso (Henares)Rowin Meijerink (Leiden Observatory)Edo Loenen (Leiden Observatory) – talk after teaAlicia Berciano Alba (Leiden Observatory/ASTRON) – next talkAxel Weiß (MPI für Radioastronomie)+ the HerCULES team

2Feedback in (U)LIRGs

Outline

Introducing HerCULES

H2O emission in (U)LIRGs

Radiation pressure dominated disks in (U)LIRGs



4

Herschel Comprehensive (U)LIRGEmissionSurvey

Open Time Key Program on the Herschel satellite

Feedback in (U)LIRGs

HerCULES in a nutshell HerCULES measures uniformly and statistically

the neutral gas cooling lines in a flux-limited sample of 29 (U)LIRGs.

Sample: all IRAS RBGS ULIRGs with S60 > 12.19 Jy (6 sources) all IRAS RBGS LIRGs with S60 > 16.8 Jy (23 sources)

Observations: SPIRE/FTS full high-resolution scans: 200 to 670 m at R ≈ 600,

covering CO 4—3 to 13—12 and [CI] + any other bright lines PACS line scans of [CII] and both [OI] lines All targets observed to same (expected) S/N Extended sources observed at several positions


Who is HerCULES?Paul van der Werf (Leiden; PI)Susanne Aalto (Onsala)Lee Armus (Spitzer SC)Vassilis Charmandaris (Crete)Kalliopi Dasyra (CEA)Aaron Evans (Charlottesville)Jackie Fischer (NRL)Yu Gao (Purple Mountain)Eduardo González-Alfonso (Henares)Thomas Greve (Copenhagen)Rolf Güsten (MPIfR)Andy Harris (U Maryland)Chris Henkel (MPIfR)Kate Isaak (ESA)Frank Israel (Leiden)Carsten Kramer (IRAM)Edo Loenen (Leiden)Steve Lord (NASA Herschel SC)

Jesus Martín-Pintado (Madrid)Joe Mazzarella (IPAC)Rowin Meijerink (Leiden)David Naylor (Lethbridge)Padelis Papadopoulos (Bonn)Dave Sanders (U Hawaii)Giorgio Savini (Cardiff/UCL)Howard Smith (CfA)Marco Spaans (Groningen)Luigi Spinoglio (Rome)Gordon Stacey (Cornell)Sylvain Veilleux (U Maryland)Cat Vlahakis (Leiden/Santiago)Fabian Walter (MPIA)Axel Weiß (MPIfR)Martina Wiedner (Paris)Manolis Xilouris (Athens)


HerCULES sampleTarget log(LIR/L)

Mrk 231 12.51

IRAS F17207—0014

12.39

IRAS 13120—5453

12.26

Arp 220 12.21

Mrk 273 12.14

IRAS F05189—2524

12.11

Arp 299 11.88

NGC 6240 11.85

IRAS F18293—3413

11.81

Arp 193 11.67

IC 1623 11.65

NGC 1614 11.60

NGC 7469 11.59

NGC 3256 11.56

Target log(LIR/L)

IC 4687/4686 11.55

NGC 2623 11.54

NGC 34 11.44

MCG+12—02—001

11.44

Mrk 331 11.41

IRAS 13242—5713

11.34

NGC 7771 11.34

Zw 049.057 11.27

NGC 1068 11.27

NGC 5135 11.17

IRAS F11506—3851

11.10

NGC 4418 11.08

NGC 2146 11.07

NGC 7552 11.03

NGC 1365 11.007Feedback in (U)LIRGs

Outline





Water in molecular clouds

H2O ice abundant in molecular clouds

Can be released into the gas phase by UV photons, X-rays, cosmic rays, shocks,...

Can be formed directly in the gas phase in warm molecular gas

Abundant, many strong transitions expected to be major coolant of warm, dense molecular gas


Herschel image of (part of) the Rosetta Molecular Cloud

Feedback in (U)LIRGs 10

Low-z H2O: M82 vs. Mrk231

At D = 3.9 Mpc, one of the closest starburst galaxies

With LIR = 31010 L , a very moderate starburst

At z=0.042, one of the closest QSOs (DL=192 Mpc)

With LIR = 41012 L , the most luminous ULIRG in the IRAS Revised bright Galaxy Sample

M82 Mrk231

H2O lines in M82

Faint lines, complex profiles

Only lines of low excitation 11Feedback in (U)LIRGs

(Weiß et al., 2010)

(Panuzzo et al., 2010)

Mrk231:strong H2O lines, high excitation


(Van der Werf et al., González-Alfonso et

al., 2010)

Mrk231: details


New detections: H2O ground state H2

18O (2 lines) H3O+ (3 lines) NH3

NH2? several unassigned

lines

H2O lines in Mrk231 Low lines: pumping

by cool component + some collisional excitation

High lines: pumping by warm component

Radiative pumping dominates and reveals an infrared-opaque (100m ~ 1) disk.

(González-Alfonso et al., 2010)


Lessons from H2O (1 + 2)


1) In spite of high luminosities, H2O lines are unimportant

for cooling the warm molecular gas.

2) Radiatively H2O lines reveal extended infrared-opaque circumnuclear gas disks.

Lessons from H2O (3)

Radiation pressure from the strong IR radiation field:


cTP /4d100rad

Since both 100 and Td are high, radiation pressure dominates the gasdynamics in the circumnuclear disk.

3) Conditions in the circumnuclear molecular disk are Eddington-limited.

Eddington-limited consequences

Eddington-limited conditions predict the LFIR-LHCN relation within factor 2 for standard dust/gas ratio (Andrews & Thompson 2011)

If accreting towards nuclear SMBH, can account for M*/M relation (Thompson et al., 2005)

Radiation pressure can expel nuclear fuel and produce Faber-Jackson relation (Murray et al., 2005)


(Andrews & Thompson, 2011)

Mechanical feedback

Radiation pressure can drive the observed molecular outflows (e.g., Murray et al., 2005)

See Susanne Aalto’s talk: flow prominent in HCN dense gas

Highest outflow velocities observed in H2O

Key process in linking ULIRGs and QSOs?

18Feedback in (U)LIRGs (Feruglio et al., 2010)

(Fischer et al., 2010)

H2O in HerCULESTarget log(LIR/L)

Mrk 231 12.51

IRAS F17207—0014

12.39

IRAS 13120—5453

12.26

Arp 220 12.21

Mrk 273 12.14

IRAS F05189—2524

12.11

Arp 299 11.88

NGC 6240 11.85

IRAS F18293—3413

11.81

Arp 193 11.67

IC 1623 11.65

NGC 1614 11.60

NGC 7469 11.59

NGC 3256 11.56

Target log(LIR/L)

IC 4687/4686 11.55

NGC 2623 11.54

NGC 34 11.44

MCG+12—02—001

11.44

Mrk 331 11.41

IRAS 13242—5713

11.34

NGC 7771 11.34

Zw 049.057 11.27

NGC 5135 11.17

IRAS F11506—3851

11.10

NGC 4418 11.08

NGC 2146 11.07

NGC 7552 11.03

NGC 1365 11.00 19Feedback in (U)LIRGs red = wet

Sample spectrum: Zw049057


Zw049057details


H2O is not XDR-driven


Only 3 bona fide AGNs in H2O sample (Mrk231, IRAS F051892524, and Arp299A)

Some pure starbursts in H2O sample (e.g., IRAS 172080014)

AGNs without strong H2O emission (e.g., NGC1365, NGC7469)

NGC7469 shows no strong H2O lines but strong OH+ emission XDR?

All of this must be compared to CO ladder PDR/XDR analysis

Luminosity dependence

Radiatively excited H2O emission ubiquitous in ULIRGs, but also seen in some LIRGs (young starbursts?)

Detection of weak H2O lines in many LIRGs and in M82 shows plenty of gas-phase H2O

key feature is the prominence of infrared-opaque clouds


Outline





The X-factor

Converting CO flux (luminosity) into H2 column density (mass):

(MW: =4; ULIRGs: =0.8)Warning: discussions of the X-

factor have been the death-blow for many conferences.


(Papadopoulos, Van der Werf, Isaak & Xilouris,

in prep.)

(U)LIRG sample

1

line

2/1

32

12

6cm 200

)H(

)CO(

)H(

K

Tnc

I

NX

1

line

2/1

32

22

6cm 200

)H(

)CO(

)H(

K

Tnc

L

M

The X-factor and optical depth

Highly turbulent motions

low optical depths( high 12CO/13CO line ratios)

low X-factor

(e.g., ULIRGs: X=0.8,Downes & Solomon 1997)


drdvT

nX

line

H2 and Both

NB: Tline is Tb of the line, not kinetic temperature

Calculating X-factors

Sample of 70 (U)LIRGs, 12CO 10, 21, 32, (43, 65) and 13CO 10, (21) lines

2 component model: high excitation and low excitation component

X-factor explicitly calculated using non-LTE excitation model and finite optical depths


Distribution of X-factors

Assumptions: Orion-like high excitation

component (not needed with denser coverage of CO ladder Herschel)

Radiation pressure supported disk LFIR/M(star forming gas) = constant (observed: LFIR/LHCN = constant; e.g., Gao & Solomon, Wu et al.)

Results: X-factors cluster between 0.5 and

1 (cf., Downes/Solomon value of 0.8 for ULIRGs) with tail up to and exceeding Milky Way values

Most (but not all!) ULIRGs have low X-factors 28Feedback in (U)LIRGs

(Papadopoulos, Van der Werf, Isaak & Xilouris,

in prep.)

(U)LIRG sample

Getting at X

Derive X from 12CO 10 65 + 13CO 10 (or 21); ideally, use HCN lines as well

Can be used at high z too, but 13CO is challenging

Why did Downes & Solomon get it right without 13CO? High quality data showing turbulent velocity field Correctly produced low optical depth Getting the optical depth right is key


Summary and outlook

Radiatively excited H2O lines select infrared-opaque nuclear regions such as found in local ULIRGs.

IR radiation pressure can be an important dynamical factor and may lead to Eddington-limited star formation.

X-factors in these regions can be derived from CO lines

Rich field for ALMA at low and high z


Documents

Der Paul van der Werf Leiden Observatory Radiative and mechanical feedback in the molecular gas in (U)LIRGs London September 16, 2011