WIYN Image: T.A. Rector, B. Wolpa and G. Jacoby (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA) A Dynamic View of Star Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics cfa-

Time: The lost concept of elementary Physics

Glossary Molecular Cloud: concentration of molecular (H 2 rather than atomic H) gas that often collapses to form stars Outflow: molecular gas observed as “redshifted” and “blueshifted” emission on either side of a young, forming star Spectral-line Map: spectra observed at a grid of pixels on the sky Extinction: the blocking out of light by shmootz (dust) “Thermal” Emission: blackbody radiation (eg. from dust)

How are Molecular Clouds Observed? Red Plate, Digitized Palomar Observatory Sky Survey The Oschin telescope, 48-inch aperture wide-field Schmidt camera at Palomar

Extinction & “Thermal” Emission IRAS Satellite Observation, 1983 Barnard’s Optical Photograph of Ophiuchus Cold (10K) dust glows, like a blackbody, in the far-infrared.

Velocity from Spectroscopy Intensity "Velocity" Observed Spectrum All thanks to Doppler Telescope  Spectrometer

Intensity "Velocity" Observed Spectrum Telescope  Spectrometer All thanks to Doppler Velocity from Spectroscopy

Radio Spectral-line Mapping

Alves, Lada & Lada 1999 Radio Spectral-Line Survey Radio Spectral-line Mapping

Velocity as a "Fourth" Dimension No loss of information Loss of 1 dimension

Question for this afternoon: Is there ever an “equilibrium” starting condition for forming stars?

Standing Still, Until the Last Minute Global Instability (e.g. Jeans) Fragments Cloud (hierarchically) time~10 6 years Hoyle 1953 Fragments Collapse Under Gravity into “Protostars” time~10 5 years

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

Molecular or Dark Clouds "Cores" and Outflows (One Round of) Star Formation, from “t=0” Jets and Disks Extrasolar System 1 pc

BUT… How long does each “phase” last and how are they mixed? 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…)

Can we simulate ticking time? Magnetohydrodynamic Computer Simulations give good approximation* of dynamic ISM, on >>0.1 pc scales (*they still need much help)

What is the right “starting” condition? 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

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

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

And can we go beyond 0.1 pc? Bate, Bonnell & Bromm 2002 MHD turbulence gives “t=0” conditions; Jeans mass=1 M sun 50 M sun, 0.38 pc, n avg =3 x 10 5 ptcls/cc forms ~50 objects T=10 K SPH, no B or  movie=1.4 free-fall times

But: Cores can be “Islands of Calm in a Turbulent Sea” "Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.

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

Order in a Sea of Chaos Order; N~R 0.9 ~0.1 pc (in Taurus) Chaos; N~R 0.1

Why care so much about time? Mass [M sun ] Velocity [km s -1 ] Power-law Slope of Sum = -2.7 (arbitrarily >2) Slope of Each Outburst = -2 as in Matzner & McKee 2000 Example 1: Episodicity changes outflow’s Energy/Momentum Deposition/time Example 2: (Some) Young stars may zoom through ISM

Outflows See references in H. Arce’s Thesis 2001

L1448 Bachiller et al B5 Yu Billawala & Bally 1999 Lada & Fich 1996 Bachiller, Tafalla & Cernicharo 1994 Position-Velocity Diagrams show YSO Outflows are Highly Episodic Velocity Position

Outflow Episodes:Position-Velocity Diagrams Figure from Arce & Goodman 200az1a HH300 NGC2264

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

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

Goodman & Arce 2002 “Giant” Herbig- Haro Flow from PV Ceph

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

moving ?? PV Ceph Episodic ejections from a precessing or wobbling moving ?? source 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

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

? The COordinated Molecular Probe Line Extinction Thermal Emission Survey

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

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

COMPLETE sampling as a path to the answer 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 (HIA, Canada) Mark Heyer (FCRAO/UMASS) Doug Johnstone (HIA, Canada) Scott Schnee (CfA, PhD student) Mario Tafalla (OAS, Spain) Tom Wilson (MPIfR/SMTO)

? The COordinated Molecular Probe Line Extinction Thermal Emission Survey Molecular Probe Line Maps (give velocity, density & temperature structure) Extinction Maps(optical and near-IR star counts & colors give density structure) Thermal Emission Maps (give density and temperature structure)

Why hasn’t this been done before? 1 day for a 13 CO map then 1 minute for a 13 CO map now

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

Pilot COMPLE TE Data

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

…and the famous “1RXS J ” is right in the Middle !? 2 pc

Is there ever an “equilibrium” starting condition for forming stars? The answer is not (yet) in the back of the book.

WIYN Image: T.A. Rector, B. Wolpa and G. Jacoby (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA) A Dynamic View of Star Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics cfa-