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)
Mar 28, 2015
Order from Chaos:Star Formation in a Dynamic Interstellar Medium
Alyssa A. GoodmanHarvard-Smithsonian Center for Astrophysics
WIYN Image: T.A. Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
Order
WIYN Image: T.A. Rector, B. Wolpa and G. Jacoby (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
Chaos
Molecular or Dark Clouds
"Cores" and Outflows
“Order”
Jets and Disks
Extrasolar System
1 p
c
Outflows
MagnetohydrodynamicWaves
Thermal Motions
MHDTurbulence
InwardMotions
SNe/GRBH II Regions
Chaos
Order in a Sea of Chaos
"Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.
Evidence for Order in a Sea of Chaos
2
3
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5
6
7
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9
1
v [
km s-1
]
3 4 5 6 7 8 91
2
TA [K]
TMC-1C, OH 1667 MHz
v=(0.67±0.02)TA-0.6±0.1
2
3
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7
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1
v i
ntr
insi
c[k
m s
-1]
6 7 8 90.1
2 3 4 5 6 7 8 91
TA [K]
TMC-1C, NH3 (1, 1)
vintrinsic=(0.25±0.02)T A-0.10±0.05
Goodman, Barranco, Wilner & Heyer 1998
“Coherent Core”“Dark Cloud”
Size Scale
Velo
city
Dis
pers
ion
Evidence for Order in a Sea of Chaos
2
3
4
5
6
7
8
9
1
v [
km s-1
]
3 4 5 6 7 8 91
2
TA [K]
TMC-1C, OH 1667 MHz
v=(0.67±0.02)TA-0.6±0.1
2
3
4
5
6
7
8
9
1
v i
ntr
insi
c[k
m s
-1]
6 7 8 90.1
2 3 4 5 6 7 8 91
TA [K]
TMC-1C, NH3 (1, 1)
vintrinsic=(0.25±0.02)T A-0.10±0.05
Goodman, Barranco, Wilner & Heyer 1998
OrderChaos
Size Scale
Velo
city
Dis
pers
ion
Order in a Sea of Chaos
"Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.
Ancient Historical Record (c. 1993)
Order; N~R0.9
~0.1 pc(in Taurus)
Chaos; N~R0.1
ModernChaos
Simulation is a preview of work by
Bate, Bonnell & Bromm…stay
tuned
Order & Chaos
What Causes Order?
What Causes Chaos?
Order
CausesIOTW: 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. 2002
Effects On Cores: Mass, angular velocity, shape, ionization fractionOn Stars: Multiplicity
This is not the topic for today…
Chaos
Quantifying Properties(briefly)
Origins(role of outflows)
How much does it matter?(question for the future)
2MASS/NICER Extinction Map of Orion
Mapping ChaosDust EmissionN, Tdust
ExtinctionN, dust sizes
Molecular Linesn, Tgas, N, v, v, xi
5:41:0040 20 40 42:00
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R.A. (2000)
1 pc
SCUBA
5:40:003041:003042:00
2:00
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R.A. (2000)
1 pc
SCUBA
Molecular Line Map
Nagahama et al. 1998 13CO (1-0) Survey
Lombardi & Alves 2001Johnstone et al. 2001 Johnstone et al. 2001
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.
MHD Simulations as an Interpretive Tool
Stone, Gammie & Ostriker 1999•Driven Turbulence; M K; no gravity•Colors: log density•Computational volume: 2563
•Dark blue lines: B-field•Red : isosurface of passive contaminant after saturation
=0.01 =1
T / 10 K
nH 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 2002.
Spectral Line Maps
Comparison of Real & Simulated Spectral-Line Maps
Fallo
ff o
f C
orr
ela
tion
wit
h S
cale
Magnitude of Spectral Correlation at 1 pc
Padoan & Goodman 2002
“Reality”
Scaled “Superalfvenic”Models
“Stochastic”Models
“Equipartition”Models
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 comparisonse.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?
The Chaos that is Outflows
1. YSO outflows are highly episodic.2. Much momentum and energy is deposited in the cloud
(~1044 to 1045 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).
Redshifted lobeBlueshifted
lobe
Velocity
Inte
nsi
ty
Velocity
Inte
nsi
ty
Outflow Maps
“Typical”(?!) Outflows
See references in H. Arce’s Thesis 2001
L1448
Bach
iller
et
al. 1
990
B5
Yu B
illaw
ala
& B
ally
199
9
Lada &
Fic
h 1
99
6
Bach
iller,
Tafa
lla &
Cern
icharo
19
94
“1. YSO Outflows are Highly Episodic”
Outflow Episodes
Figure
fro
m A
rce &
Goodm
an 2
00
1
HH300
NGC2264
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)
A Good Guess about Episodicity
e.g. HH300
Arce & Goodman 2001b
Reipurth et al. 2000
Episodicity on Many Scales
Plus “axis wandering”!
B5Yu, Billawala, Bally, 1999
Mass-Velocity Relations can bevery steep, especially in “bursty-looking” sources…
“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?
-3
-8
-4
-8
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.
10-5
10-4
10-3
10-2
10-1
100
Mass
[M
sun]
0.12 3 4 5 6 7 8
12 3 4 5 6 7 8
102
Velocity [km s-1]
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 = -2as in Matzner & McKee 2000
Arce & Goodman 2001b
“2. Much momentum and energy is deposited in the cloud (~1044 to 1045 erg, comparable or greater than
cloud K.E.).”BUT: Is there a “typical” amount?
H. Arce’s Thesis 2001
“3. Some cloud features are all outflow. That’s how much gas is
shoved around!”
Arce & Goodman 2001b; 2002a
“4. Powering source of (some) outflows may move rapidly through ISM.”
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
“4. Powering source of (some)
outflows may move rapidly through ISM.”
Goodman & Arce 2002
Goodman & Arce 2002
HST WFPC2 Overlay: Padgett et al. 2002
Arce & Goodman 2002
Goodman & Arce 2002
Trail & Jet
Trails of Deception4x1018
3
2
1
0
y knot positions (cm)
-4x1017
-2 0
x knot posns. w.r.t. star "now" (cm)
500x1015
400
300
200
100
0
Distance along x-direction (cm)
15x103
1050
Elapsed Time since Burst (Years)
70
60
50
40
30
20
10
0
Knot Offset/Star Offset (Percent)
Knot
Star
Star-KnotDifference
Star-KnotDifference
(%)
Initial jet 250 km s-1; star motion 10 km s-1
How Many Outflows are
There at Once?
What is their cumulative
effect?
How Many Outflows are
There at Once?
What is their cumulative
effect?
Action of Outflows(?) in NGC 1333 •SCUBA 850 m Image shows Ndust (Sandell & Knee 2001)•Dotted lines show CO outflow orientations (Knee & Sandell 2000)
Chaos
Quantifying PropertiesSCF
OriginsRole of Outflows
How much does it matter?The COMPLETE Survey
SIRTF’s1st Plan for
Star-FormingRegions
The SIRTFLegacySurvey
“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)
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
Our Plan for theFuture:
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)
2MASS/NICER Extinction Map of Orion
Un(coordinated) Molecular-Probe Line, Extinction
and Thermal Emission
Observations
5:41:0040 20 40 42:00
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SCUBA
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1 pc
SCUBA
Molecular Line Map
Nagahama et al. 1998 13CO (1-0) Survey
Lombardi & Alves 2001Johnstone et al. 2001 Johnstone et al. 2001
The Value of CoordinationC18ODust EmissionOptical
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 C18O 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
Is this Really Possible Now?
10-4
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Time (hours)
20152010200520001995199019851980
Year
1 Hour
1 Minute
1 Day
1 Second
1 Week
SCUBA-2
SEQUOIA+
NICER/8-m
NICER/SIRTFNICER/2MASS
AV~5 mag, Resolution~1'
AV~30 mag, Resolution~10"
13CO Spectra for 32 Positions in a Dark Cloud (S/N~3)
Sub-mm Map of a Dense Core at 450 and 850 m
1 day for a 13CO map then
1 minute for a 13CO map now
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 AV>2”
FCRAO/SEQUOIA 13CO and 13CO Observations: gas temperature, density and velocity information ~40" resolution on all AV>1
Science:Combined Thermal Emission (SIRTF/HHT) 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 will be enabled—for 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
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" resolutionFCRAO+ IRAM N2H+ 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 N2H+ map with CS spectra superimposed.
(Le
e,
Mye
rs &
Ta
falla
20
01
).
Order from Chaos:Star Formation in a Dynamic Interstellar Medium
Alyssa A. GoodmanHarvard-Smithsonian Center for Astrophysics
WIYN Image: T.A. Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
Chaos