Interstellar Matter and Star Formation in the Magellanic Clouds François Boulanger (IAS) Collaborators: Caroline Bot (SSC), Emilie Habart (IAS), Monica Rubio(U. de Chile), François Viallefond (LERMA)

Large and Small Magellanic Clouds Nearest (50 kpc) external galaxies: face on view at ISM in galaxies  Dense interstellar matter and star formation from large to small scales Low metallicity (1/4 and 1/10 for the LMC and SMC)  Impact on molecular cloud structure and chemistry  galaxy formation: templates for early steps and continuing evolution (matter in the outer part of disks) Giant star forming regions : templates for star burst galaxies  Radiative and dynamic impact of massive stars on the ISM

Topics Tracing dense matter in low metallicity gas Molecular gas in the vicinity of the 30 Doradus superstar cluster Ongoing work calling for APEX observing programs Based on the analysis of SEST (CO and Simba) observations together with infrared data (ISO, Spitzer, H 2 and Br  )

Relation L CO - M VIR NANTEN Survey Fukui et al.

Impact of reduced metal abundance on chemical structure of clumpy clouds Lequeux, Le Bourlot et al A&A

Dust clouds in SMC SIMBA 1.2 mm Bot (2005, PhD) SIMBA and CO(2-1) Spitzer 24  m - Bollato et al.

Dust mm and CO emission vs metallicity Molecular ring and Solar Neighborhood molecular clouds (FIRAS and CO from the Dame et al. survey) compared to SMC data  Same Dust 1mm/CO average ratio  X=N(H 2 )/S CO  1/Z with significant cloud to cloud scatter Molecular ring

S(1.2mm, dust) -> M(H 2 ) N H = S 1.2mm. (x d MW /x d SMC )/  d MW. B 1.2mm (T)) –SIMBA –x d MW /x d SMC = 6 (Based on abundances) –  d MW (2x diffuse ISM value) –T=15 K (based on FIRAS spectra Galactic clouds) To be compared with Mvir from ∆V CO et R CO Cloud masses from dust observations

f=M H ( 1.2mm )/M vir larger than 1 in SMC clouds = 2 (1 for Solar Neighborhood clouds)  Significant magnetic support (B ~ 10 µG)? Dust and virial masses LIRS49 SMCB2 N SMCB2 S LIRS36 SMCB1#1 SMCB1# ± ± ± ± ± ± 0.5 Bot (2005, PhD)

Molecular gas and massive star formation LMC NANTEN CO survey on H  Fukui et al.

30 Doradus: Hot, warm and cold X-ray Chandra Spitzer/IRAC

Warm to cold N Br  /CO HST

Molecular gas around R136 H S(1) and CO 2-1 contours Accelerated molecular clumps within CO(2-1) spectrum towards R136

Molecular Clumps Within the wind blown bubble H 2 /Br  contours No PAH counter part Within Molecular Cloud outside the Bubble H2/PAH emission ratio => nH 2 ~ 10 5 cm -3, f surface = 0.1

Bubble Expansion Equations from Weaver et al. (1977) applied to R136 Expansion breaks out Molecular Cloud at 5 pc. Shell stops to shield Molecular Cloud from inoization as its density (set by the bubble pressure) drops

Triggered Star Formation Molecular clumps within cavity  Are these clumps massive enough to form stars?  Is star formation still proceeding? Clumpy molecular cloud with increased interclump pressure due to ionization  Triggered star formation acts over the whole cloud volume not only at its surface  Formation of future super star cluster?

APEX observations APEX observation of dust cloud in SMC Monica Rubio Strong motivation for an LMC/SMC coordinated APEX program on gas spectrsocopy and dust emission Related to Spitzer surveys`(dust and star formation)  Census of dense matter ith dust sub-mm observations  Probing density structure with gas observations  Chemistry