Stars Forming in a Dynamic Interstellar Medium Alyssa

Stars Forming in a Dynamic Interstellar Medium Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics cfa-www. harvard. edu/~agoodman WIYN Image: T. A. Rector, B. Wolpa and G. Jacoby (NOAO/AURA/NSF) and Hubble Heritage Team (STSc. I/AURA/NASA)

Stars Forming in a Dynamic ISM When the World Stood Still (except at the last minute) Allowing Time to Tick, and not always start at zero – Episodic Outflows – PV Ceph: Protostar Caught Speeding? COMPLETE sampling as a path to the answer – Carefully-designed statistical questions – Serendipity (so far: warm dust ring around X-ray source in Ophichus, odd velocity features in Perseus…)

Standing Still, Until the Last Minute Fragments Collapse Under Gravity into “Protostars” time~105 years Global Instability (e. g. Jeans) Fragments Cloud (hierarchically) time~106 years Hoyle 1953

Standing Still, Until the Last Minute A Group of Young “Zero-Age Main Sequence” Stars is Born

Ticking, from t=0 "Cores" and Outflows 1 pc Molecular or Dark Clouds Jets and Disks Extrasolar System

BUT… • How long does each “phase” last and how are they mixed? (Big cloud--“Starless” Core--Outflow-Planet Formation--Clearing) • What is the time-history of star production in a “cloud”? Are all the stars formed still “there”? • How do processes in each phase impact upon each other? (Sequential star formation, outflows reshaping clouds…)

Stars Forming in a Dynamic ISM • MHD turbulence gives “t=0” conditions; Jeans mass=1 Msun • 50 Msun, 0. 38 pc, navg=3 x 105 ptcls/cc • forms ~50 objects • T=10 K • SPH, no B or L, G • movie=1. 4 free-fall times Bate, Bonnell & Bromm 2002

What is the right “starting” condition? b=0. 01 Stone, Gammie & Ostriker 1999 [T / 10 K] b=[ 2 -3 n. H / 100 cm ][ B / 1. 4 G] 2 b=1 • Driven Turbulence; M K; no gravity • Colors: log density • Computational volume: 2563 • Dark blue lines: B-field • Red : isosurface of passive contaminant after saturation

Evaluating Simulated Spectral Line Map of MHD Simulations: The Spectral Correlation Function (SCF) Simulated map, based on work of Padoan, Nordlund, Juvela, et al. Excerpt from realization used in Padoan & Goodman 2002.

Falloff of Correlation with Scale How Well can Molecular Clouds be Modeled, Today? Summary Results from SCF Analysis “Equipartition” Models “Reality” “Stochastic” Models Scaled “Superalfvenic” Models Magnitude of Spectral Correlation at 1 pc Padoan & Goodman 2002

Cores: Islands of Calm in a Turbulent Sea? "Rolling Waves" by Kan. O Tsunenobu © The Idemitsu Museum of Arts.

Islands of Calm in a Turbulent Sea Goodman, Barranco, Wilner & Heyer 1998

Islands (a. k. a. Dense Cores) AMR Simulation Ask about velocity gradients later Simulated NH 3 Map Berkeley Astrophysical Fluid Dynamics Group http: //astron. berkeley. edu/~cmckee/bafd/results. html Barranco & Goodman 1998

Observed ‘Starting’ Cores: 0. 1 pc Islands of (Relative) Calm “Dark Cloud” “Coherent Core” TMC-1 C, OH 1667 MHz TMC-1 C, NH 3 (1, 1) -0. 10± 0. 05 D v intrinsic =(0. 25± 0. 02)T 1 9 8 8 7 7 -1 ] 9 D v intrinsic [km s -1 v [km s ] Velocity DDispersion 1 A 6 5 4 3 3 Dv=(0. 67± 0. 02)T 2 6 3 4 5 -0. 6± 0. 1 A 6 7 8 9 1 TA [K] Goodman, Barranco, Wilner & Heyer 1998 2 2 6 7 Size Scale 8 9 0. 1 2 3 TA [K] 4 5 6 7 8 9 1

Order in a Sea of Chaos ~0. 1 pc (in Taurus) Order; N~R 0. 9 Chaos; N~R 0. 1

So, can we simulate ticking time? • MHD Simulations give good approximation of dynamic ISM, on >>0. 1 pc scales • Physical scale (reality) of ~0. 1 pc SPH simulations starting from a turbulent “t=0” is debatable (no B, T=const, etc. ) – Observations indicate relative calm just before stars form

Why care about time? 10 0 Power-law Slope of Sum = -2. 7 Mass [Msun] (arbitrarily >2) 10 -1 10 -2 10 -3 10 -4 10 -5 Slope of Each Outburst = -2 as in Matzner & Mc. Kee 2000 0. 1 2 3 4 5 6 78 10 2 Velocity [km s-1] Example 1: Episodicity changes outflow’s Energy/Momentum Deposition/time Example 2: (Some) Young stars may zoom through ISM

Example 1: Episodicity in Outflows See references in H. Arce’s Thesis 2001

L 1448 Bachiller, Tafalla & Cernicharo 1994 YSO Outflows are Highly Episodic B 5 Yu Billawala & Bally 1999 Bachiller et al. 1990 Lada & Fich 1996 Position-Velocity Diagrams show Velocity

Outflow Episodes: Position-Velocity Diagrams NGC 2264 Figure from Arce & Goodman 200 az 1 a HH 300

• Slope steepens when t corrections made – Previously unaccounted-for mass at low velocities • Slope often (much) steeper than “canonical” -2 • Seems burstier sources have steeper slopes? Mass/Velocity “Steep” Mass-Velocity Relations -3 -8 Velocity -4 -8 HH 300 (Arce & Goodman 2001 a)

Mass-Velocity Relations in Episodic Outflows: Steep Slopes result from Summed Bursts 10 0 Power-law Slope of Sum = -2. 7 Mass [Msun] (arbitrarily >2) 10 -1 10 -2 10 -3 10 -4 10 -5 Slope of Each Outburst = -2 as in Matzner & Mc. Kee 2000 0. 1 2 3 4 5 6 78 10 2 Velocity [km s-1] Arce & Goodman 2001 b

Example 2: Powering source of (some) outflows may zoom through ISM

“Giant” Herbig-Haro Flow from PV Ceph 1 pc Image from Reipurth, Bally & Devine 1997

PV Ceph Episodic ejections from a precessing or wobbling moving ? ? source Goodman & Arce 2002

Optical “cones” Elongated ~N-S HST WFPC 2 Overlay: Padgett et al. 2002 Goodman & Arce 2002 Dense gas elongated along direction of motion Arce & Goodman 2002

Trail & Jet Goodman & Arce 2002

How much gas will be pulled along for the ride? Goodman & Arce 2002

Just how fast is PV Ceph going?

Insights from a “Plasmon” Model Initial jet 250 km s 1; star motion 10 km s-1 Goodman & Arce 2002

Insights from a “Plasmon” Model Goodman & Arce 2002

Stars Forming in a Dynamic ISM When the World Stood Still (except at the last minute) Allowing Time to Tick, and not always start at zero – Episodic Outflows – PV Ceph: Protostar Caught Speeding? COMPLETE sampling as a path to the answer – Carefully-designed statistical questions – Serendipity (so far: warm dust ring around X-ray source in Ophichus, odd velocity features in Perseus…)

Nagahama et al. 1998 13 CO (1 -0) Survey Un(coordinated) Molecular. Probe Line, Extinction and Thermal Emission Observations Molecular Line Map 2 MASS/NICER Extinction Map of Orion Johnstone et al. 2001 Lombardi & Alves 2001 Johnstone et al. 2001

The COordinated Molecular Probe Line Extinction Thermal Emission Survey COMPLETE sampling as a path to the answer Alyssa A. Goodman, Principal Investigator (Cf. A) João Alves (ESA, Germany) Héctor Arce (Caltech) Paola Caselli (Arcetri, Italy) James Di. Francesco (HIA, Canada) Doug Johnstone (HIA, Canada) Scott Schnee (Cf. A, Ph. D student) Mario Tafalla (OAS, Spain) Tom Wilson (MPIf. R/SMTO)

5 degrees (~tens of pc) COMPLETE, Part 1 SIRTF Legacy Coverage of Perseus Observations: 2003 -- Mid- and Far-IR SIRTF Legacy Observations: dust temperature and >10 -degree scale Near-IR Extinction, Molecular Line and Dust Emission Surveys of Perseus, Ophiuchus & Serpens column density maps ~5 degrees mapped with ~15" resolution (at 70 m) 2002 -- NICER/2 MASS Extinction Mapping: dust column density maps ~5 degrees mapped with ~5' resolution 2003 -- SCUBA Observations: dust column density maps, finds all "cold" source ~20" resolution on all AV>2” 2002 -- FCRAO/SEQUOIA 13 CO and 13 CO Observations: gas temperature, density and velocity information ~40" resolution on all AV>1 Science: –Combined Thermal Emission data: dust spectral-energy distributions, giving emissivity, Tdust and Ndust –Extinction/Thermal Emission inter-comparison: unprecedented constraints on dust properties and cloud distances, in addition to high-dynamic range Ndust map –Spectral-line/Ndust Comparisons Systematic censes of inflow, outflow & turbulent motions enabled

(Lee, Myers & Tafalla 2001). COMPLETE, Part 2 (2003 -5) FCRAO N 2 H+ map with CS spectra superimposed. <arcminute-scale core maps to get density & velocity structure all the way from >10 pc to 0. 01 pc Observations, using target list generated from Part 1: NICER/8 -m/IR camera Observations: best density 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)

A statistical question for COMPLETE: How Many Outflows are There at Once? What is their cumulative effect? Action of Outflows(? ) in NGC 1333 SCUBA 850 mm Image shows Ndust (Sandell & Knee 2001) Dotted lines show CO outflow orientations (Knee & Sandell 2000)

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

…yes, it’s possible

COMPLETE: JCMT/SCUBA >10 mag AV 8 6 4 2 ~100 hours at SCUBA 10 pc Ophiuchus Perseus Johnstone, Goodman & the COMPLETE team, SCUBA 2003(? !)

COMPLETE Preview: Discovery of a Heated Dust Ring in Ophiuchus 2 pc Goodman, Li & Schnee 200

…and the famous “ 1 RXS J 162554. 5 -233037” is right in the Middle !? 2 pc

Stars Forming in a Dynamic Interstellar Medium Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics cfa-www. harvard. edu/~agoodman WIYN Image: T. A. Rector, B. Wolpa and G. Jacoby (NOAO/AURA/NSF) and Hubble Heritage Team (STSc. I/AURA/NASA)

Core “Rotation”? ? 0. 1 pc FWHM Gradient “Beam” N 2 H+ in TMC-1 C; Schnee & Goodman 2003

Core “Rotation”? ? N 2 H+ in TMC-1 C; Schnee & Goodman 2003

Core “Rotation”? ? N 2 H+ in TMC-1 C; Schnee & Goodman 2003

Core “Rotation”? ? N 2 H+ in TMC-1 C; Schnee & Goodman 2003

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

SIRTF Legacy Survey MIRAC Coverage 2 degrees ~ 10 pc

The Value of Coordination Optical Image Dust Emission C 18 O 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 B 68. 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 B 68 to be essentially a perfect critical Bonner-Ebert sphere NICER Extinction Map Radial Density Profile, with Critical Bonnor-Ebert Sphere Fit