Hunt for Molecules in Local Universe Galaxies

Santiago GARCIA-BURILLO

Observatorio Astronómico Nacional (OAN)-Spain

Hunt for Molecules, November 19-20, 2005, Paris, France

ISM properties in SBs and AGN

Spectacular energies injected in gas reservoirs of SB and AGN through radiation fields(UV, X-rays) shocks and cosmic rays modify:

-Physical properties of molecular gas

-Chemistry of molecular gas

Molecular Gas Chemistry in Starbursts (SBs) and Active Galactic Nuclei (AGNs)

Science driver of an ongoing IRAM survey of SBs and AGN:

´to go beyond CO maps’

‘team’=(Garcia-Burillo, Usero, Fuente, Gracia, Planesas, Boone, Tacconi, Schinnerer, Aalto…)

High sensitivity+resolution required: 30m (see also pioneering work of Mauersberger, Henkel,

Huttemeister et al) and PdBure interferometer (the main focus here!).

Evolutionary trends in SB can be tracked down by observation of different chemical tracers

I/ ONSET OF THE NUCLEAR STARBURST: gas infall driven by density waves and/or tidal forces.

II/ MASSIVE STAR FORMATION BURSTS: Young Stellar Objects and first SN explosions

III/ BIPOLAR GIANT OUTFLOW: gas plane breaks out due to blast waves of SN remnants.

PHASES

•Gas compression, HI H2, cloud-cloud

collisions driving large-scale SHOCKS.

PROCESSES

•UV field from massive stars create HII regions and PDR locally in disk.

• SHOCKS in YSO in disk

•XDR when AGN in disk.

•Strong UV fields create giant PDR in disk

•Expansion of gas heated by SN entrains neutral gas into halo driving SHOCKS

•PDR / SHOCKS in halo?

Tracking down Galaxy Evolution through Chemistry

Energetic Processes in SB & AGN (intense UV/X Radiation, Shocks,Cosmic Rays...)

Need of higher resolution--->Interferometer maps

Large-Scale Shocks in Galaxies

Large-Scale Shocks in Galaxies

•First high-resolution SiO image of a galaxy, made with PdB interferometer.

•NGC253: barred spiral with nuclear SB=region I.

•Widespread SiO emission (v=0,J=2-1) over 600pc-disk (regions I + II :X(SiO)10-10 -10-9 )--->beyond the nuclear starburst (region I).

II

•Region II: coincides with bar resonance

(ILR):----->large-scale shocks induced by density waves in the disk

García-Burillo et al. 2000

NGC2533mm-cont

SiO

H13CO+

I

Usero, García-Burillo et al. 2005, A&A, submitted

• Molecular gas distribution shaped by the bar: SiO emission along northern spiral arm + nuclear ring.

• SiO extends beyond the radiocontinuum thermal emission ->

shocks are not powered by on-going star formation!

Left: SiO integrated intensity (contours) on 3.5mm RC (color) PdBI maps. Right: H13CO+ (contours) on SiO (color) PdBI maps. SiO-to- H13CO+ integrated intensity ratio.

• X(SiO) = (2-7)10-10 (nuclear ring) to (1-4)10-9 (northern spiral arm).

Large-Scale Shocks in GalaxiesIC342

•Turbulence of shocked gas is enhanced compared to the quiescent gas.

Left: H13CO+ (contours) on SiO (color) PdBI maps. Right: SiO and H13CO+ position-velocity diagrams.

•A fraction of kinetic energy cascades down to smaller scales.

•Shocks arise in a turbulent clumpy medium.

IC342 Large-Scale Shocks in GalaxiesUsero, García-Burillo et al. 2005, A&A, submitted

-->large-scale shocks in IC342 are driven by density waves: X(SiO) largest at x1/x2 orbit crossing-->cloud cloud collisions enhanced.

SiO kinematics

•PdBI maps show SiO emission extends out of galaxy plane!

•Two features with X(SiO) (2-4)x 10-10:

-a/ SiO chimney.

-b/ SiO supershell.

supershell

SiO chimney:

•Filament of 500pc size

•X(SiO)(2-4)x10-10

•M(H2)6x106 M

SiO supershell:

•Created by supercluster of young stars.

•M(H2)1.6x107 M SiO map (contours) on 4.8GHz continuum image (grey) from Wills et al 1999

Large-Scale Shocks in GalaxiesM82García-Burillo et al. 2001

chimneySiO

->large-scale shocks in the disk-halo interface: building up the gaseous halo

--->Widespread HCO emission detected in PdBI map of the nucleus of M82 (García-Burillo et al 2002)

--->Global HCO abundances comparable to PDR: X(HCO)~4x10-10(Hollis & Churchwell, 1983; Snyder et al 1985; Schilke et al 2001)

--->Interferometer map shows strong variations of X(HCO) within disk: --->PDR Chemistry propagates.

NeII contours(Achtermann & Lacy 1995) on HCO map (grey)

-->M82 disk is a giant PDR of 600 pc size (Mao et al 2000, García-Burillo et al 2002; Fuente et al 2005)

PDR Chemistry in GalaxiesM82

HCO contours(García-Burillo et al 2002) on CO map (grey; Weiss et al 2001)

García-Burillo et al. 2002

PDR Chemistry in GalaxiesM82Fuente, García-Burillo, Gerin et al. 2005a, 2005b

Results of multispecies 30m survey of M82

->Complex carbon chemistry: C3H2, CH3C2H, C2H

->High [CN]/[HCN] ratio ~ 5

->Low [HCO+]/[HOC+] ratio ~ 40

Le Bourlot et al´s model

M82----> small (r<0.2pc) and dense (nH2~ 10 4-5) molecular clouds immersed in intense UV-field (G0=104)

…and detection of CO+!

CO(1-0) (PdBI;Schinnerer et al. 00)

Molecular Gas Inventory of the CND of NGC1068

-->X-ray driven chemistry models explain abundance ratios measured in the CND of NGC1068 (Usero et al 2004)

-->X-rays suspected to heavily influence molecular gas chemistry in the nuclear disks of AGN (Tacconi et al 1994, Maloney et al 1996)

XDR Chemistry in GalaxiesNGC1068Usero, García-Burillo, Fuente et al. 2004 Multispecies 30m survey of NGC1068

X(HCO+)/X(HOC+)~300-6000-->X(e-)~10-7-10-6 (typically measured in molecular clouds).

X(HCO+)/X(HOC+) measured in the CND of NGC1068 (~30-80) can be reached in XDR if X(e-)~10-5-->molecular gas is highly ionized

XDR Chemistry in GalaxiesNGC1068Usero, García-Burillo, Fuente et al. 2004

->The HCO+ / HOC+ equilibrium

The 400pc-size CND of NGC1068 has become a giant XDR--->embedded AGNs can alter significantly the chemistry of molecular gas-->relevant for high-z galaxies

Molecular Gas Chemistry in ULIRGsULIRGsGracia, García-Burillo, Planesas et al. 2005, in prep

•Ultraluminous Infrared Galaxies (ULIRGs, i.e., LIR (>1012Lo ): extreme starbursts and/or embedded AGNs? Puzzle: LCO not correlated with LIR (Solomon et al. 1997).

•Gao & Solomon (2004ab) show fraction of dense gas (LHCN/LCO) is correlated with LIR--> starburst origin for ULIRGs!?.

•Our HCO+ survey of LIGs and ULIGs (Gracia et al. 2005) show that HCO+/CO is fairly constant as a function of LIR!! -->at odds with the picture drawn from HCN .

Probing dense gas in ULIRGs

L HCN(1-0) / L CO(1-0) L HCO+(1-0) / L CO(1-0)

The HCN view

The HCO+ view

Which one is ‘‘wrong’’?

Molecular Gas Chemistry in ULIRGsULIRGsGracia, García-Burillo, Planesas et al. 2005, in prep

Is HCN an unbiased tracer of dense gas in ULIRGs?

‘Chemistry’ is key to understand what lurks inside ULIRGs!

L HCN(1-0) / L HCO+(1-0)

Infrared pumping of HCN lines-->higher I(HCN)

XDR-driven chemistry in embedded AGNs-->enhancement of X(HCN)

hot-core driven chemistry in starbursts-->higher X(HCN)

Unexpected correlation with LIR!

Potential bias of HCN

•Large-scale molecular shocks in the: pre-starburst phase (e.g., NGC253, IC342, Maffei2) post-starburst phase (e.g., M82)

Conclusions and PerspectivesExtragalactic Chemistry in low-z Universe: tracking down the evolution in local starbursts/AGNs

•Giant PDRs in starburst disks (e.g., M82)

•XDRs in AGNs (e.g., NGC1068)

Extragalactic Chemistry in high-z Universe?:

•High-z Universe is the playground for extreme+embedded starbursts and AGNs.

•Evolution in extreme+embedded starbursts will be probed by

molecular lines with ALMA-->need of local (low z) templates!!.

•SiO traces shocks in the disk-halo interface in M82: giant outflow, evolved starburst.

•SiO traces shocks in the disk of NGC253 (SF, density waves...): less evolved starburst.

High spatial resolution needed to trace evolution in starburstsHigh spatial resolution needed to trace evolution in starbursts

NGC253 M82

SiO IRAM PdBI map in NGC253 from García-Burillo et al 2000.

10´´

SiO IRAM-PdBI map (contours) from García-Burillo et al. 2001 on CO (2-1) map from Weiss et al 2001 (colour ) in M82.

Extragalactic Chemistry: Using Interferometers

Extragalactic Chemistry: Using Interferometers

OVRO maps of IC342 (Meier and Turner 2005)

High spatial resolution is key to probe chemical differentation in galaxies!

•Large-scale molecular shocks in the: pre-starburst phase (e.g., NGC253, IC342, Maffei2) post-starburst phase (e.g., M82)

Conclusions and PerspectivesExtragalactic Chemistry in low-z Universe: tracking down the evolution in local starbursts/AGNs

•Giant PDRs in starburst disks (e.g., M82)

•XDRs in AGNs (e.g., NGC1068)

Extragalactic Chemistry in high-z Universe?:

•High-z Universe is the playground for extreme+embedded starbursts and AGNs.

•Evolution in extreme+embedded starbursts will be probed by

molecular lines with ALMA-->but we need to study local (low z) templates first!!.

Summary

First SiO interferometer maps in SB/AGN show emission on scales of ~200-700pc (NGC253, M82, IC342, NGC1068).

Variable enhancement of SiO (X(SiO)=10-8-10-10 ) reveal uneven shock processing: evolution along SB sequence.

•Highly sensitive mm-interferometers can study molecular inventory in ‘active’ galaxies ‘beyond CO’.

•Information provided by tracers of PDR, XDR and Shock Chemistry key to understand evolution of ISM content in SB and AGN.

SHOCK Chemistry at work...

HCO interferometer map in M82 shows propagation of PDR Chemistry in ~600 pc disk.

HCO detected in NGC1068 starburst ring.

30m+PdBure maps (HCN, SiO, CN, HCO+,HOC+..) reveal XDR Chemistry in the 200pc CND of NGC1068.

XDR Chemistry at work...

PDR Chemistry at work...

Summary

First SiO interferometer maps in SB/AGN show emission on scales of ~200-700pc (NGC253, M82, IC342, NGC1068).

Variable enhancement of SiO (X(SiO)=10-8-10-10 ) reveal uneven shock processing: evolution along SB sequence.

•Highly sensitive mm-interferometers can study molecular inventory in ‘active’ galaxies ‘beyond CO’.

•Information provided by tracers of PDR, XDR and Shock Chemistry key to understand evolution of ISM content in SB and AGN.

SHOCK Chemistry at work...

HCO interferometer map in M82 shows propagation of PDR Chemistry in ~600 pc disk.

HCO detected in NGC1068 starburst ring.

30m+PdBure maps (HCN, SiO, CN, HCO+,HOC+..) reveal XDR Chemistry in the 200pc CND of NGC1068.

XDR Chemistry at work...

PDR Chemistry at work...

PDR Chemistry in GalaxiesM82Fuente, García-Burillo, Gerin et al. 2005a, 2005b

Results of multispecies 30m survey of M82

->Complex carbon chemistry: C3H2, CH3C2H, C2H

->High [CN]/[HCN] ratio ~ 5

->Low [HCO+]/[HOC+] ratio ~ 40

M82----> small (r<0.2pc) and dense (nH2~ 10 4-5) molecular clouds immersed in intense UV-field (G0=104)

Detection of CO+!

ISM properties in SBs and AGN vs quiescent star forming galaxy disks

Models from mm/IR point out to significant differences. Spectacular energies injected in gas reservoirs of SB and AGN (radiation fields, winds, shocks...).

Physical properties of molecular gas in SB/AGN

Need of multilines/multispecies studies.

Chemistry of molecular gas in SB/AGN

Influence of radiation fields(UV, X-rays) vs shock processing on the chemical status of molecular gas.

Science driver of IRAM survey of SB and AGN: ´beyond CO maps’

High sensitivity+resolution required: 30m and PdBure interferometer

Interferometer maps using tracers of star formation (CS,HCN, CN, HCO+,SiO...)

Interferometer maps using chemical tracers of Photon-Dominated-Regions (PDR) , X-ray-Dominated-Regions (XDR), and Shock Chemistry

Molecular Gas Chemistry in SB and AGN

•IRAM PdBI one-field map shows SiO emission extends out of galaxy plane!: chimney+supershell.

SiO supershell

SiO chimney

OVRO CO(1-0) map :Walter et al 2002

Molecular gas drawn out of galaxy disks: starbursts

M82: a huge molecular gas halo! (Seaquist and Clark 2001, García-Burillo et al 2001, Walter et al 2002)

The tip of the iceberg!

•ALMA will make possible high-resolution mapping of extreme starbursts as M82: key to understand high-z galaxies !

Dynamics of Disks (IV): The Disk-Halo Interface

PdBI SiO(2-1) map: García-Burillo et al 2001

Shock Chemistry in NGC253

•Strong non-circular motions modelled as gas response to bar

•‘Parallelogram signature’: ring II = outer Inner Lindblad Resonance (oILR) where orbit crowding and large-scale shocks are expected.

•The average value of X(SiO) is high: >10-10 , i.e. an order of magnitude above PDR standards.

•X(SiO) increases in outer region II, reaching 10-9.

•Large-scale shocks driven by DW resonances efficiently enhance SiO abundances.

Shock Chemistry: IC342 and NGC253

IC342: Usero et al. 2005, A&A, submitted

3.5mm radiocontinuum PdBI map (contours) on H +continuum HST image (color).

SO(32-21) PdBI map of NGC253.

NGC253: Usero et al. 2005, in prep.

• Different molecules provide

diagnostic tools to explore starburst evolution: M82 and NGC253 show different chemistries

M82

NGC253

M82 and NGC253 spectra (~4GHz broad) by S. Martín (private communication)

2mm Survey (~40GHz broad) of the NGC253 with IRAM 30m (Martín et al. 2003, 2004)

NGC253

Extragalactic Chemistry: Expanding the Frequency Range

LINE SURVEYS

->Pioneering work of R. Mauersberger+C. Henkel (80-90’s) done with 30m telescope (12’’-27’’ resolution) in some galaxies for a limited number of molecular species.