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Order from Chaos: Star Formation in a Dynamic Interstellar Medium Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics WIYN Image: T.A. Rector.

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Presentation on theme: "Order from Chaos: Star Formation in a Dynamic Interstellar Medium Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics WIYN Image: T.A. Rector."— Presentation transcript:

1 Order from Chaos: Star Formation in a Dynamic Interstellar Medium Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics WIYN Image: T.A. Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)

2 Order

3 WIYN Image: T.A. Rector, B. Wolpa and G. Jacoby (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA) Chaos

4 Molecular or Dark Clouds "Cores" and Outflows Order Jets and Disks Extrasolar System 1 pc

5 Outflows Magnetohydrodynamic Waves Thermal Motions MHD Turbulence Inward Motions SNe/GRB H II Regions Chaos

6 Order in a Sea of Chaos "Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.

7 Evidence for Order in a Sea of Chaos v [km s ] T A [K] TMC-1C, OH 1667 MHz v=(0.67±0.02)T A -0.6± v intrinsic [km s ] T A [K] TMC-1C, NH 3 (1, 1) v intrinsic =(0.25±0.02)T A -0.10±0.05 Goodman, Barranco, Wilner & Heyer 1998 Coherent CoreDark Cloud Size Scale Velocity Dispersion

8 Evidence for Order in a Sea of Chaos v [km s ] T A [K] TMC-1C, OH 1667 MHz v=(0.67±0.02)T A -0.6± v intrinsic [km s ] T A [K] TMC-1C, NH 3 (1, 1) v intrinsic =(0.25±0.02)T A -0.10±0.05 Goodman, Barranco, Wilner & Heyer 1998 OrderChaos Size Scale Velocity Dispersion

9 Order in a Sea of Chaos "Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.

10 Ancient Historical Record (c. 1993) Order; N~R 0.9 ~0.1 pc (in Taurus) Chaos; N~R 0.1

11 Modern Chaos Simulation is a preview of work by Bate, Bonnell & Bromm…stay tuned

12 Order & Chaos What Causes Order? What Causes Chaos?

13 Order Causes IOTW: What sets the scale for the Transition to Coherence? Probably ~ inner scale of magnetized turbulence (often ~0.1 pc) see Larson 1995; Goodman et al. 1998; Goodman, Caselli et al Effects On Cores: Mass, angular velocity, shape, ionization fraction On Stars: Multiplicity This is not the topic for today…

14 Chaos Quantifying Properties (briefly) Origins (role of outflows) How much does it matter? (question for the future)

15 Mapping Chaos Dust Emission N, T dust Extinction N, dust sizes Molecular Lines n, T gas, N, v, v, x i Molecular Line Map Nagahama et al CO (1-0) Survey Lombardi & Alves 2001Johnstone et al. 2001

16 Quantifying the Properties of Chaos The Spectral Correlation Function and other sharp tools can be used to compare real and simulated spectral line data cubes. Simulations can map these tools product onto physics.

17 MHD Simulations as an Interpretive Tool Stone, Gammie & Ostriker 1999 Driven Turbulence; M K; no gravity Colors: log density Computational volume: Dark blue lines: B-field Red : isosurface of passive contaminant after saturation =0.01 =1 T /10 K n H 2 /100 cm -3 B /1.4 G 2

18 Simulated map, based on work of Padoan, Nordlund, Juvela, et al. Excerpt from realization used in Padoan & Goodman Spectral Line Maps

19 Comparison of Real & Simulated Spectral-Line Maps Falloff of Correlation with Scale Magnitude of Spectral Correlation at 1 pc Padoan & Goodman 2002 Reality Scaled Superalfvenic Models Stochastic Models Equipartition Models

20 Comparison of Real & Simulated Spectral-Line Maps Results so far show: –Driven turbulence gives a approximation to real ISM (see Padoan & Goodman 2002). Still for the future: Customized simulation-to-reality comparisons e.g. Do the number of outflows observed in a region effect the observed Mach number there, and does a simulation with that Mach number match that observed cloud well? Do the details of the forcing matter? What happens if detailed outflow simulations are included in more global simulations? Is the reality match improved in any way?

21 The Chaos that is Outflows 1.YSO outflows are highly episodic. 2.Much momentum and energy is deposited in the cloud (~10 44 to erg, comparable or greater than cloud K.E.)--capable of maintaining some degree of chaos. 3.Some cloud features are all outflow. 4.Powering source of (some) outflows may move rapidly through ISM. See collected thesis papers of H. Arce. (Arce & Goodman 2001a,b,c,d; Goodman & Arce 2002).

22 Redshifted lobe Blueshifted lobe Velocity Intensity Velocity Intensity Outflow Maps

23 Typical(?!) Outflows See references in H. Arces Thesis 2001

24 L1448 Bachiller et al B5 Yu Billawala & Bally 1999 Lada & Fich 1996 Bachiller, Tafalla & Cernicharo YSO Outflows are Highly Episodic

25 Outflow Episodes Figure from Arce & Goodman 2001 HH300 NGC2264

26 Numerical Simulation of Steady Jet PV diagrams for the shell material at three inclinations cut along the outflow axis for the steady jet simulation; i is the inclination of the outflow to the plane of the sky. Solid lines are calculated using the mean velocity of the shell material. Dashed lines are calculated using the velocity of the newly swept-up material. Dotted lines indicate the zero velocity. (Lee, Stone, Ostiker & Mundy 2001)

27 A Good Guess about Episodicity

28 e.g. HH300

29 Arce & Goodman 2001b Reipurth et al Episodicity on Many Scales Plus axis wandering!

30 B5 Yu, Billawala, Bally, 1999 Mass-Velocity Relations can be very steep, especially in bursty- looking sources…

31 Steep M-v Relations HH300 (Arce & Goodman 2001a) Slope steepens when corrections made –Previously unaccounted-for mass at low velocities Slope often (much) steeper than -2 Seems burstier sources have steeper slopes?

32 Numerical Simulation of Bow- Shock Jet MV relationships at three inclinations for the steady jet simulation. Both the redshifted (open squares) and blueshifted (filled squares) masses are shown. The dashed lines are the fits to the redshifted mass with a power-law MV relationship, where the power-law index,, is indicated at the upper right-hand corner in each panel. The solid line at i = 0° is calculated from the ballistic bow shock model.

33 Mass-Velocity Relations in Episodic Outflows: Steep Slopes result from Summed Bursts Power-law Slope of Sum = -2.7 (arbitrarily >2) Slope of Each Outburst = -2 as in Matzner & McKee 2000 Arce & Goodman 2001b

34 Numerical Simulation of (Sinusoidally-)Pulsed Jet Lee, Stone, Ostiker & Mundy 2001

35 2. Much momentum and energy is deposited in the cloud (~10 44 to erg, comparable or greater than cloud K.E.). BUT: Is there a typical amount? H. Arces Thesis 2001

36 3. Some cloud features are all outflow. Thats how much gas is shoved around! Arce & Goodman 2001b; 2002a

37 4. Powering source of (some) outflows may move rapidly through ISM.

38 Giant Herbig-Haro Flow in PV Ceph Reipurth, Bally & Devine pc

39 PV Ceph: Episodic ejections from precessing or wobbling moving source Implied source motion ~10 km/s (4 mas/year) assuming jet velocity ~100 km/s Goodman & Arce 2002

40 4. Powering source of (some) outflows may move rapidly through ISM. Goodman & Arce 2002

41 HST WFPC2 Overlay: Padgett et al Arce & Goodman 2002

42 Goodman & Arce 2002 Trail & Jet

43 How much gas will be pulled along for the ride? Goodman & Arce Radius [pc] Radius [arcsec at 500 pc] 1050 M Sun M Sun Effective Bondi-Hoyle Radius for 10 M Sun in eff =1.7 km s Gas eff 2 =(1.7 km s ) 2

44 Trails of Deception Initial jet 250 km s -1 ; star motion 10 km s -1

45 Insights from a Plasmon Model

46 How Many Outflows are There at Once? What is their cumulative effect?

47 Action of Outflows(?) in NGC 1333 SCUBA 850 m Image shows N dust (Sandell & Knee 2001) Dotted lines show CO outflow orientations (Knee & Sandell 2000)

48 Chaos Quantifying Properties SCF Origins Role of Outflows How much does it matter? The COMPLETE Survey

49 SIRTFs 1st Plan for Star-Forming Regions The SIRTF Legacy Survey From Molecular Cores to Planet-Forming Disks Neal J. Evans, II, Principal Investigator (U. Texas) Lori E. Allen (CfA) Geoffrey A. Blake (Caltech) Paul M. Harvey (U. Texas) David W. Koerner (U. Pennsylvania) Lee G. Mundy (Maryland) Philip C. Myers (CfA) Deborah L. Padgett (SIRTF Science Center) Anneila I. Sargent (Caltech) Karl Stapelfeldt (JPL) Ewine F. van Dishoeck (Leiden)

50 SIRTF Legacy Survey Perseus Molecular Cloud Complex (one of 5 similar regions to be fully mapped in far-IR by SIRTF Legacy)

51 SIRTF Legacy Survey MIRAC Coverage 2 degrees ~ 10 pc

52 Our Plan for the Future: COMPLETE The COordinated Molecular Probe Line Extinction Thermal Emission Survey Alyssa A. Goodman, Principal Investigator (CfA) João Alves (ESA, Germany) Héctor Arce (Caltech) Paola Caselli (Arcetri, Italy) James DiFrancesco (Berkeley) Doug Johnstone (HIA, Canada) Scott Schnee (CfA) Mario Tafalla (OAS, Spain) Tom Wilson (MPIfR/SMTO)

53 Un(coordinated) Molecular-Probe Line, Extinction and Thermal Emission Observations Molecular Line Map Nagahama et al CO (1-0) Survey Lombardi & Alves 2001Johnstone et al. 2001

54 The Value of Coordination C 18 O Dust Emission Optical Image NICER Extinction Map Radial Density Profile, with Critical Bonnor-Ebert Sphere Fit Coordinated Molecular-Probe Line, Extinction & Thermal Emission Observations of Barnard 68 This figure highlights the work of Senior Collaborator João Alves and his collaborators. The top left panel shows a deep VLT image (Alves, Lada & Lada 2001). The middle top panel shows the 850 m continuum emission (Visser, Richer & Chandler 2001) from the dust causing the extinction seen optically. The top right panel highlights the extreme depletion seen at high extinctions in C 18 O emission (Lada et al. 2001). The inset on the bottom right panel shows the extinction map derived from applying the NICER method applied to NTT near-infrared observations of the most extinguished portion of B68. The graph in the bottom right panel shows the incredible radial-density profile derived from the NICER extinction map (Alves, Lada & Lada 2001). Notice that the fit to this profile shows the inner portion of B68 to be essentially a perfect critical Bonner-Ebert sphere

55 Is this Really Possible Now? 1 day for a 13 CO map then 1 minute for a 13 CO map now

56 COMPLETE, Part 1 Observations: Mid- and Far-IR SIRTF Legacy Observations: dust temperature and column density maps ~5 degrees mapped with ~15" resolution (at 70 m) NICER/2MASS Extinction Mapping: dust column density maps, used as target list in HHT & FCRAO observations + reddening information ~5 degrees mapped with ~5' resolution HHT Observations: dust column density maps, finds all "cold" source ~20" resolution on all A V >2 FCRAO/SEQUOIA 13 CO and 13 CO Observations: gas temperature, density and velocity information ~40" resolution on all A V >1 Science: Combined Thermal Emission (SIRTF/HHT) data: dust spectral-energy distributions, giving emissivity, T dust and N dust Extinction/Thermal Emission inter-comparison: unprecedented constraints on dust properties and cloud distances, in addition to high-dynamic range N dust map Spectral-line/N dust Comparisons Systematic censes of inflow, outflow & turbulent motions will be enabledfor regions with independent constraints on their density. CO maps in conjunction with SIRTF point sources will comprise YSO outflow census 5 degrees (~tens of pc) SIRTF Legacy Coverage of Perseus

57 COMPLETE, Part 2 Observations, using target list generated from Part 1: NICER/8-m/IR camera Observations: best density profiles for dust associated with "cores". ~10" resolution SCUBA Observations: density and temperature profiles for dust associated with "cores" ~10" resolution FCRAO+ IRAM N 2 H + Observations: gas temperature, density and velocity information for "cores ~15" resolution Science: Multiplicity/fragmentation studies Detailed modeling of pressure structure on <0.3 pc scales Searches for the "loss" of turbulent energy (coherence) FCRAO N 2 H + map with CS spectra superimposed. (Lee, Myers & Tafalla 2001).

58 Order from Chaos: Star Formation in a Dynamic Interstellar Medium Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics WIYN Image: T.A. Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)

59 Chaos

60 Revealing Order? ~0.5 pc

61 HH300: Integrated 12 CO(1-0) Outflow on 13 CO line width, with 13 CO spectra


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