HST HII regions & optical light Eva Schinnerer Max Planck Institute for Astronomy molecular gas (PAWS) 1 kpc Star Formation and ISM in Nearby Galaxies: The PAWS View

3 Paradigms on Giant Molecular Clouds 1.most of the molecular gas resides in GMCs 2.GMC properties are universal across environments/galaxies 3.massive star formation and GMCs are closely associated

9 kpc release of public data products: early 2012 IRAM Large Program 30m: 40 hr PdBI: 170 hr M51

PdBI Arcsecond Whirlpool Survey Eva Schinnerer (PI)MPIA Annie HughesMPIA Dario ColomboMPIAPoster #14 Sharon MeidtMPIA Adam LeroyNRAO Jerome PetyIRAM Gaelle DumasIRAM Karl SchusterIRAM Clare DobbsMPE Todd ThompsonOSU Santiago Garcia- Burillo OAN Carsten KramerIRAM Hans-Walter RixMPIA

PAWS – PdBI Arcsecond Whirlpool Survey largest PdBI mosaic done 60 pointings split in 2 sets FoV ~ 43” per pointing sensitivity reached:5  ~1 GMC 1.2x10 5 M sun at 40 pc (1.1’’) resolution CO(2-1) HERA Schuster et al. (2007)

Molecular Gas Disk of M51 Schuster et al. (2007) single dish (~ 500 pc)

Molecular Gas Disk of M51 Schinnerer et al. (in prep.) mm-interferometer (~ 40pc)

Molecular Gas disk of M51 Colombo et al. (in prep.) Velocity field

Molecular Gas disk of M51 Colombo et al. (in prep.) environmental mask nuclear bar in center inter-arm spiral arm

Stellar Potential  Spiral Arms are not the Same 3.6  m corrected Meidt et al. (in prep.)

3 Paradigms on Giant Molecular Clouds 1.most of the molecular gas resides in GMCs 2.GMC properties are universal across environments/galaxies 3.massive star formation and GMCs are closely associated

Resolved Emission in Molecular Gas Disk combined resolved extended 100% 33% 66% combined – resolved (PdBI-only) = extended intensity velocity Pety et al. (in prep.)

GMC Fraction in Molecular Gas Disk CO(1-0) intensity linear stretch

GMC Fraction in Molecular Gas Disk Colombo et al. (in prep.) GMCs only preliminary(!)

GMC Fraction in Molecular Gas Disk Colombo et al. (in prep.) Preliminary analysis: ~ 900 GMCs identified ~ 50% have M(H 2 ) > 10 6 M sun ~ 30% of total CO flux center: 13% inter-arm: 40% spiral arms: 47%

Diffuse Component in Molecular Gas Disk 12 CO/ 13 CO = 6, 8, 11 23’’ Pety et al. (in prep.) 12 CO/ 13 CO consistent w/ mixture of diffuse & dense material (e.g. Polk et al. 1988)

3 Paradigms on Giant Molecular Clouds 1.most of the molecular gas resides in GMCs  Not at all, but further testing required 2.GMC properties are universal across environments/galaxies 3.massive star formation and GMCs are closely associated

GMC Properties I. Biases Colombo et al. (in prep.) log r [pc] Log  v [km/s] We used: same GMC extraction algorithm & parameters (CPROPS) (following Bolatto et al. 2008) CO data cubes at native resolution  resolution bias on GMC properties  deblending issue in crowded regions (?) resolution limits Poster #14  Dario Colombo

‘GMC’ Properties II. Nearby Galaxies Hughes et al. (in prep.) same extraction parameters (CPROPS) for ‘islands’ data cubes at same resolution   CO not the same log r [pc] log L CO [K km/s/pc 2 ] 1 M sun /pc log M lum [M sun ] log N cl [(m>M)/kpc 2 ] If average disk scale height same  Different mass spectra

log r [pc] ‘GMC’ Properties III. Galactic Environment Colombo et al. (in prep.) Same extraction parameters (CPROPS) on single data set   CO the same irrespective of galactic environment  Mass spectrum highly dependent on environment (crowding?) log L CO [K km/s/pc 2 ] 1 M sun /pc log M lum [M sun ] log N cl [(m>M)/kpc 2 ] M51

SFR surface density (M sun /yr/kpc 2 ) 30 disk 1 kpc Bigiel et al. (2011) depletion time t= H 2 surface density (M sun /pc 2 ) M51 LMC GMC Properties in Different Environments

3 Paradigms on Giant Molecular Clouds 1.most of the molecular gas resides in GMCs  Not at all, but further testing required 2.GMC properties are universal across environments/galaxies  No, arm/inter-arm, low/high  gas 3.massive star formation and GMCs are closely associated

Relation of Gas and Star Formation aperture size I(CO) > 3  inter-arm center CO non-detection …. OLS 1kpc Larger apertures: scatter decreases slope steepens SFRI(CO)HI+H GHz  m HH  m Hughes et al. (in prep.) log I CO [K km/s] log  H  [erg/s/cm 2 /sr]

20cm HST i-H 24  m HST H  Spatial Relation of Gas and Star Formation Schinnerer et al. (in prep.)

Spatial Relation of Gas and Star Formation ISM: CO & I-H potential well: H band star formation: B band

CO, IR, CO+IR Spatial Relation of Gas and Star Formation CO, Ha, CO+Ha 1.9” 6.0” 12” CO, RC, CO+RC 80 pc 250 pc 500 pc

Relation of Gas and Giant HII regions 90 pc apertures centered on grouped HII regions: effects of age and environment? 1:1 correspondence log  H  [erg/s/pc 2 ] Log  H2 [M sun /pc 2 ]

Dobbs & Pringle (2010) GMC & SF Formation in Spiral Wave Model when and where does SF start?  Dobbs (2008)  gas spurs/feathers should develop

Northern spiral arm molecular gas in arms and spurs/feathers (as expected from models)

Northern spiral arm molecular gas in arms and spurs/feathers HII regions w/i spurs/feathers, no H  in gas arm (Vogel ea 1988)

Northern spiral arm molecular gas in arms and spurs/feathers HII regions w/i spurs/feathers, no H  in gas arm no hot dust emission in gas arm  delay between GMC and star formation?

3 Paradigms on Giant Molecular Clouds 1.most of the molecular gas resides in GMCs  Not at all, but further testing required 2.GMC properties are universal across environments/galaxies  No, arm/inter-arm, low/high  gas 3.massive star formation and GMCs are closely associated  Not always, depends on environment

GMC Properties in Different Environments PropertyM51LMCNotes ΣH 2 [M pc -2 ]851global ΣHI [M pc -2 ]830global Z/Zo30.5global Σ* [M/pc -2 ]~300~50global ΣH 2 [M pc -2 ]23030cloud T max [K]42cloud σ v [km s -1 ]72cloud R [pc]8020cloud Two ISM ‘extremes’: LMC properties from Hughes et al. (2010)

The conversion factor in M51a’s spiral arms 13 CO(1-0) 12 CO(1-0) 12 CO(2-1) Ideally add more lines: higher transitions or isotopes, but …

13 CO(1-0) 12 CO(1-0) Ideally add more lines: higher transitions or isotopes, but … LVG Large Velocity Gradient (LVG analysis)  values for T kin, n(H 2 ) very similar to MW