Starbursts, Star Clusters & Blowing the Galactic Winds J. S. Gallagher-U. Wisconsin-Madison L.
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Starbursts, Star Clusters & Blowing the Galactic Winds
J. S. Gallagher-U. Wisconsin-Madison L. J. Smith-STScI/UCL M. Westmoquette-UCL R. W. O’Connell- UVa R. de Grijs-U. Sheffield & Other Collaborators
Champaign-Urbana Last century, circa 1984--idea of compact young massive star clusters to understand “W-R galaxies”
1993 Space Sci Rev 66, 37
• SPIRAL GALAXY DISKS & OUR ASTROPHYSICAL WORLD VIEW. Connection to large scale structure of host galaxy--Jean’s gravitational instability on large spatial scales--but lazy star formation in well separated regions.
• STARS MADE FROM BOUND CLOUDS. Range of young star clustering scales from expanding OB associations to bound open star clusters.
M51 N Arm WIYN UVI
Ground-based biases: Current intense SF--small scale events- Poorly resolved at 1-2 arcsec image quality.
Enter HST, VLA & Chandra..
M100 nuclear disk--surprise! luminous young compact star clusters
Hunter et al. 1995 ApJ, 448, 179
Archetype: 30 Doradus: small super star cluster or “SSC”
(
R
) 0
R
3 Berstein & Novaki 1999, APOD
Stellar connections--cYMCs or SSCs
•
the stars
--SSCs contain lots (100s) of massive stars, & as L~M -> many stars ~ a super star with phases- • W-R, RSG flash, etc.
the physics--
winds on galactic scales are thermally driven but still share many characteristics--have to • worry about gas flows, etc.
the locations--
SSCs/cYMCs occupy and trace regions of recent star formation
SBc Spiral NGC 2903 WFPC2: Nuclear Region Star Cluster Systems
D. Smith et al. 2004
2MASS NIR Image NGC 253 Visual
Nuclear Starburst: NGC 253 X-ray & Ionized Superwind
Giant SBc V
rot
~200 km/s
Pietsch, Vogler, Klein, & Zinnecker 2000, A&A, 360, 24 & Watson et al. WFPC2 GTO
..but how do the winds work? Steady state? Biconical?
Mass loaded? Confined? Cosmic ray enhanced? …
Sufficient continuous mechanical power: supersonic steady state wind with sonic point
Lamers & Cassinelli 1999, Introduction to Stellar Winds Subsonic Supersonic outflow
When velocity > velocity sound shocks complicate gas physics!
M82 M. Westmoquette from Hubble Heritage HST/ACS Data
Wind Wind
NGC4027 QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.
M82-Barred Disk Galaxy
QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.
M. Westmoquette, 200y Ph.D thesis UCL
M82-WIYN + HST Wind in optical H +[NII] vs.
Spitzer IRAC 3.6-8 micron SINGS: 1. Dusty wind 2. Northern wind plume more optically obscured?
NW Semi-obscured back side
A1 has a small H II region Westmoquette et al. 2007, ApJ, 671
Ionized gas in Region A H [N II] Emission lines resolved - broad; Vel. Disp = 45 km/s [N II] [S II] doublet: N e is high ~ 1000 cm -3 ; [S II] Ambient ISM has thermal P/k ~ 10 7 P/k ~ 3x10 8 K and turbulent A1 is in an unusually high pressure environment which will control its evolution.
Westmoquette et al. 2007, ApJ, in press
L. Smith et al 2006, MNRAS, 370, 513. By fitting STIS spectra to SB99 models, we derive an age of 6-7 Myr for M82-A1 and a mass of 10 6 M . Individual OB stars mostly hidden within compact star clusters. Dense cluster star forming mode dominates.
From ACS images, we derive a cluster radius of 3.0
± 0.5 pc and an H II region radius of 4.5
± 0.5 pc
2-D models by Tenorio-Tagle & collabs-->> stalled complex winds In dense SSCs due to cooling.
30 Msun/yr 2008, ApJ
Conceptual local model: feedback in action
Shocked high pressure ISM; T≈10 7 K, c s ≈ 400 km/s, near hydrostatic, v(expand)< symmetric broad line components A. A. Suchkov et al. 1996, ApJ, 463, 528 QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture. M82-High x-ray brightness -> mass loading Where? How much? Entrainment? Mass entrainment== matter carried along as bulk unit in the flow. Mass loading== Injecting cooler matter into the hot phase. Increases density, lowers T, enhances cooling & X-rays: L (T)n 2 . (Also dust!!) Dramatic?!! SSC M82-A1 A C “Socialized” photoionization Southern Wind roots connect to starburst clumps A & C -> feedback a LOCALLY driven process! M82: HST WFPC2 + WIYN Interfaces!!! Sheets & shells Access to (astro)physics M82: clump => assemblages of ≈10 Myr old compact star clusters + SFR 1 Msun/yr in 0.1 kpc 2 . L(mech) = 10 42 -10 43 erg/s => dM/dt(wind) ≈ Msun/yr + Wind is mass loaded in clump and reaches sonic point at about 1 z(scale) + Collimation is poor and occurs on a starburst clump scale + Gas is entrained; broken shells are one major contributor + Inner wind likely to be unsteady but SNe II time scale leads to overall steady wind + As in Tenorio-Tagle model, winds and O star locations correlated => photoionization! Tenorio-Tagle et al. cluster-cluster collimated winds: evolve with individual SSCs within starburst clumps. Multiple wind streams model Gas outflows & young stars spatially correlated Large collimation surface/flow volume ratio--enhanced entrainment + mass loading +channeled photoionization High gas column density where UV escapes. Cluster wind basic model: Tenorio-Tagle, Silich, Munoz-Tunon 2003 ApJ, 597, 279 Distance (kpc) M82-Outflow HII Velocities QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture. Ideal steady state thermal winds : solution passes through critical point -->> supersonic wind with V w ~V esc ~ 1000 km/s Physics connections across boundaries from stars to galaxies Please insert energy here Sonic point wind leads to power source Lamers & Cassinelli 1999, Introduction to Stellar Winds Cloud response to steady shocking: wind mass loading via galactic “comets” QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture. Melioli et al. 2005, A&A, 443, 495 Hubble Ultradeep Field: High-z Clumpy & Compact Starbursts Intense star formation: ~2/3 of all existing stars! 40+ Msun/yr Interaction? NGC7673--HST--Homeier et al. Bournaud et al. 2008 A&A, 486 Bournaud et al. 2007 ApJ, 670 Clump-clusters--interactions AND disk instabilities A few thoughts for the start of the morning: Intense star formation can be highly clustered. Clusters of cYMCs have major feedback effects on the host galaxy -superbubbles to strong winds. Connect to redistribution of baryons and metals post-galaxy formation. Regions with SSCs tend to have high ISM pressures. High stellar densities within SSCs could modify some aspects of stellar evolution--e.g. dust production in RSG. SSCs are likely to be important factories for the production of massive binaries--with some ejected by SNe II to become HMXRBs. Structures and masses of SSCs parallel globular clusters--present day windows into processes of the past? Clump-clusters important in early evolution of galaxy disks. Chandra X-ray contours: wind mass loading + entrainment + shock thermalization Enhanced SFE per M mol SFE/cloud core ≈ constant Galactic Starburst Winds: Stellar Powered Outflows Extended HII Extended X-ray (+dual AGN) R. Van der Marel: GO-6430 NGC6240--Ultraluminous merger Jay Gallagher University of Wisconsin-Madison & Linda Smith University College London QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Harris et al. 2001, AJ Compact HII in disk, more broadly ionized region exterior to central plane from material entrained in wind? M83 Cluster Ages-Harris et al. (2001) • Low resolution spectroscopy - blue/near UV • Magellanic Cloud star clusters • Starburst cluster ages & velocities • Field stellar population age mixes • HII region properties QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. WIYN K’ NGC 5253 core HST +Keck IR XMM X-ray Imaging: Global view of M82 Superwind kT≈ 0.5+0.9 kev kT≈ 0.4+0.7 kev Z HOT ≈0.3 solar QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture. Stevens et al. 2003, MNRAS, 343, L47 (also X ray studies by Strickland, Heckman…) 200 pc M82-A1 Ionized gas in lower wind structured into filaments & loops---flow walls or??? M82 SSCs & Starburst Clumps: V-band WFPC2 6 1/2 L. J. Smith et al. 2006, MNRAS, 370, 513 Why are nuclear region clusters compact? Consider the g tides 1/ 3 c r t M 3 M g c ( r ) 1/ 3 r r t r v c 2 2 c 1/ 3 Cluster radial expansion is bad for survival! heated dust = radiation field gas density Point sources - dust input from evolved stars 10 B A M82 SSCs & Starburst Clumps: V-band WFPC2 Clustered cYMCs in space & time--grav instability in gas rich disks t dynf r i 2 v c GM r i pc v 250 M 6 1 C 1 df Gyr Possible issue for massive clusters near galaxy centers with bulges; clusters should move inwards, tidally disrupt, and contribute to bulge. CAUTION: Results depend on cluster ORBITS; e.g., little dynamical friction in smoothly rotating disk with circular orbits. Super star clusters OB star “sheet”: the starburst core B A 10 P. Anders, U. Goettingen; data HST: ESA/NASA Composite spectra: Mixture of ages--high mass stars, >30-40 Msun WR stars present in SSCs; RSGs in cluster A: merging clusters. Cluster A Cool star Ho & Filippenko 1996, ApJ, 466, L83 WR* NGC 1569 - NIR with WIYN 3.5-m Telescope; Natural Seeing 10 A B Moderate mechanical luminosity: DISK BLOWOUTS Supershells: Halo Blowouts--vent into halos from disks. Hot interior partially confined by cooler shell Disk Photoionized surface Generally V(exp) << v(esc) Weaver et al. 1977, ApJ and later models Effects on HI vs fate of hot gas? Mac Low et al. 1989, ApJ, 337, 141 NGC1569: SSCs important high v(exp) supershell drivers. Some likely to escape… eventually… M. Westmoquette, L. Smith, J. Gallagher 2007 MNRAS submitted C. Martin 1998, ApJ, 506, 222 HI QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. HI Kinematic supershells in NGC 1569 M82 --COMPACT STAR CLUSTERS GALORE! Most stars form and live early lives in compact clusters, Often clsutered into starburst “clumps”. M82-Hubble Heritage Near hydrostatic base consistent with critical point wind models--e.g., Shopbell & Bland Hawthorn (1998, ApJ, 493, 129). BUT is this a coherent bipolar wind? Hydrostatic Model Lamers & Cassinelli 1999, Introduction to Stellar WindsKey Role of Molecular Content
Environments of Young Super Star Clusters
Nuclear disk starburst in M83
Nuclear Disk Geometry: 2D Embedded Star Formation
Southern African Large Telescope 10.5-m
Nuclear Starbursts: NGC 253
A
C
M82-A1 SSC: M~10
M
- r
~3 pc - t~7 Myr
~ 0.1
0.2
Dwarf Starbursts: NGC1569: HII Region “Socialism” in Starbursts-Spatially Extended Photo-Ionization
Cluster Dynamical Evolution: Dynamical Friction
1.2
(ln
)
~ 0.3(
/ 200
)
NGC 1569: Gas-Rich Dwarf Starburst Galaxy