Colloquium given at NASA/JPL

Shocks and
star formation
Lars Kristensen
SubMillimeter Array Fellow,
Harvard-Smithsonian Center for Astrophysics
SMA
SMITHSONIAN
ASTROPHYSICAL
O
BSERVATORY
A
C
ADEMIA SINICA
IA
A

Colliding galaxies
Galactic outﬂows
Supernova remnants
Planetary nebulae
Young stars
Solar system / ISM
Earth / Sun
Supersonic ﬂight

Colliding galaxies
Galactic outﬂows
Supernova remnants
Planetary nebulae
Young stars
Solar system / ISM
Earth / Sun
Supersonic ﬂight
Shocks are everywhere

What is a shock?
• “... any pressure-driven disturbance which is
time-independent (in a co-moving reference
frame) and which effects an irreversible change
in the state of the medium.” (Draine 1980)

What is a shock?
• “... any pressure-driven disturbance which is
time-independent (in a co-moving reference
frame) and which effects an irreversible change
in the state of the medium.” (Draine 1980)
• “A hydrodynamical surprise” (Chernoff 1987)

Why should you care?
1000 K
100 K
50 K
10 K
2.7 K
103 104 105 106 107
Temperature
Density (cm-3)Slide credit: E. Bergin

Diffuse
1000 K
100 K
50 K
10 K
2.7 K
103 104 105 106 107
Temperature

Diffuse
Molecular clouds
1000 K
100 K
50 K
10 K
2.7 K
103 104 105 106 107
Temperature

Diffuse
Molecular clouds
1000 K
100 K
50 K
10 K
2.7 K
103 104 105 106 107
Temperature
Density (cm-3)
Star formation
Slide credit: E. Bergin

Shocks
Diffuse
Molecular clouds
1000 K
100 K
50 K
10 K
2.7 K
103 104 105 106 107
Temperature
Density (cm-3)
Star formation
Slide credit: E. Bergin

CO, H2O:  
dominant coolants and probes
G. J. Herczeg: Warm water in a Class 0 outﬂow
Herczeg et al. (2012)

Part I 
Water tracing shocks in embedded protostars
Part II 
Hot water in disks: a shocked wind origin
Part III 
Low-mass protostars in high-mass clusters

Part I
Water tracing shocks in
embedded protostars

Low-massYSO evolution
ARCE & SARGENT1082 Vol. 64
Class 0 Class IIClass I
Jet / wind present at all evolutionary stages
Arce & Sargent (2006)

Physical processes
101
103
102
104
T (K)
R.Visser
Outﬂow (entrained)
Passively heated envelope
Disk
UV-heating of cavity walls
Shell shocks along cavity walls
Jet w. internal working surfaces
Shocks dominate heating processes

Water traces shocks
“Bullet” “Bullet”
Broad
outﬂow
Envelope emission
+ absorption =
inverse P-Cygni
Offset comp.
BHR71
15 L⊙◉☉
2.7 M⊙◉☉
• One proﬁle: lots of
H2O moving!
• Bulk of emission in
three components
• Velocity resolution
allows for
decomposition
Herschel-HIFI
Kristensen et al. (2012)

H2O always trace shocks
Class 0 Class I

• Proﬁle richness in Class 0/I
sources: disentangling
dynamics
• When, how, where is the gas
moving along the line of sight?
Class 0 Class I

• Proﬁle richness in Class 0/I
sources: disentangling
dynamics
• When, how, where is the gas
moving along the line of sight?
• The devil is in the detail proﬁle
Class 0 Class I

~1-10 ~102-103 ~104-105 L⊙◉☉

Time
Mass
D
=
1kpc
D = 200 pc
100 km s-1
x275 x25
x250
x140
H2O proﬁle evolution
H2O 110-101
557 GHz
Time more important
than mass in evolution
Caselli et al., Hogerheijde et al., Kristensen
et al., McCoey et al., van derTak et al.

Evolutionary
scheme
• Class 0: H2O
tightly linked to
outﬂow, infall,
molecular jet
• Class I: envelope
opens, outﬂow
force decreases,
expansion
(Kristensen et al. 2012)

Part II
Hot water in disks:
a wind origin?

Hot H2O detected with Spitzer
• A true surprise
• Detected toward Class II
disk sources
• Interpretation: inner hot
disk, r < 1 AU
composition of protoplanetary disks is expected
to hold clues to the processes that are active in
disks. Although significant advances have been
made from the study of the dust properties of
disks (3–5), much less progress has been made
in the study of the gaseous component, partic-
ularly over the range of radii where planet for-
mation is thought to occur (6–8). Measurements
of disk molecular abundances can provide in-
sights on issues such as the origin and evolution
of water in the Solar System, the nature of or-
ganic chemistry in disks, and the ability of
disks to synthesize pre-biotic species. Here we
report that a protoplanetary disk around a young
star displays a rich molecular emission spectrum
in the mid-infrared that provides detailed
thermal and chemical information on gas in the
planet formation region of the disk.
We observed AA Tauri, a fairly typical clas-
sical T Tauri star (CTTS, which are approximately
solar-mass stars with accretion disks and ages of
less than a few 106
years), with the Infrared Spec-
trograph (IRS) on the Spitzer Space Telescope
(9, 10), covering wavelengths of 9.9 to 37.2 mm
at a spectral resolution (l/Dl) of 600. The high
signal-to-noise ratio (~200 to 300) produced by
our observational and data reduction techniques
(11) reveals a rich spectrum of molecular emis-
sion lines that is dominated by rotational tran-
demonstrate a disk origin for their near-infrared
molecular emission features. These include emis-
sion from the 5-mm fundamental ro-vibrational
bands of CO, which is very common in CTTSs
(12), and emission from the 2.3-mm CO overtone
bands and hot bands of H2O and OH (6, 13, 14),
which is less frequently observed. All these near-
infrared emission bands are thought to arise in a
temperature inversion in the atmosphere of the
inner [<1 astronomical unit (AU)] disk (6, 12–14).
To determine the properties of the emitting
gas, we modeled the emission spectrum and an-
alyzed the measured line fluxes using standard
techniques (11). The emission from each molec-
The higher mean tempera
derstood by the fact that
sion is insensitive to gas w
of the higher energy of
transitions and the shorter w
Vertical gradients in the
molecular abundances co
some of the differences; fo
abundant in a cooler par
compared to CO (16).
The abundances of sim
for AA Tauri (Fig. 3) are a
nitude higher than both o
(19) of hot molecular cor
1
Remote Sensing Division, Naval Research Laboratory, Code
7210, Washington, DC 20375, USA. 2
National Optical Astron-
omy Observatory, Tucson, AZ 85719, USA.
14 MARCH 2008 VOL 319 SCIENCE www.sciencemag.org1504
Carr & Najita 2008

0
500
1,000
1,500
2,000
2,500
3,000
3,500
-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12
J
E/k(K)
ortho -H2O para -H2O
102,9-93,6,
321 GHz
81,8-70,7
63 μm
Hot H2O
• My deﬁnition:
Anything with
Eup > 1000 K
• Typically observed
with Spitzer, Herschel-
PACS, ground-based
NIR/MIR
Watson et al. 2007
HIFI land
PACS land
Spitzer
land

• Observed the 63 mu line,
spectral resolution ~ 100 km/s
• Detected in 24% of gas-rich
disks
• Emission, when detected,
correlates with [OI] also at 63
mu
• No spatial extent seen: disk
origin?
PACS hot water in disksP. Riviere-Marichalar et al.: Detection of warm wa
Table 2. Probabilities for correlations between o-H2O line intensity and
stellar/disc parameters.
Observable Points n Spearman’s prob. Kendall’s prob.
L[OI] 68 0.0009 (0.4090) 0.0000 (0.196)
63 µm flux 64 0.0147 (0.2635) 0.0002 (0.4567)
850 µm flux(2)
57 0.0145 (0.2596) 0.0131 (0.8496)
Lstar
(3)
65 0.1789 (0.1130) 0.1980 (0.5535)
LX
(3)
65 0.0225 (0.9912) 0.0087 (0.6012)
α(2−8 µm) (4)
62 0.026 (0.1547) 0.0023 (0.3850)
L[OI]6300 Å 27 0.1291 (0.3255) 0.1008 (0.3450)
Notes. The values obtained for random populations are shown in brack-
ets. Accurate only if N > 30. (2) 850 µm continuum fluxes from
Andrews & Williams (2005). (3) Values from Güdel et al. (2007)
(4) SED slope from Luhman et al. (2010).
Fig. 1. Spectra for the objects with a 63.32 µm feature detection (>3σ). The red lines indicate the rest wavelength of
Photodetector Array Camera and Spectrometer (Poglitsch et al.
2010).
In this Letter, we report the first detection of the o-H2O line
at 63.32 µm in a subsample of protoplanetary discs around T
Tauri stars in the 1–3 Myr old Taurus star forming region.
2. Observations and data reduction
This study is based on a sample of 68 classical and weak-line
T Tauri stars from the Taurus star forming region with spectral
measurements from Herschel-PACS centred at the wavelength
of the [O i] 3
P1 →3
P2 63.184 µm line. The Taurus star-forming
Table 1. Line positions and fluxes from P
Name Sp. type λH2O − λ[OI]
– – µm 1
AA Tau K7 0.140
DL Tau K7 0.141
FS Tau M0 0.139
RY Tau K1 0.139
T Tau K0 0.138
XZ Tau M2 0.139 3
HL Tau K7 0.142 5
UY Aur M0 0.139 3
Notes. All spectral types from the compil
centre position. When the star was w
Riviere-Marichalar et al. 2012

Origin of hot PACS H2O
• Following Spitzer hot
H2O interpretation:
inner warm disk,
T ~ 600 K
• No need for shocks/
winds?
P. Riviere-Marichalar et al.: Detection of warm water vapour in Taurus protoplanetary discs by Herschel
Appendix A: Non detections
GASPS is a flux-limited survey. All sources have detection lim-
its for the o-H2O line at 63.32 µm around 10−17
W/m2
, with an
uncertainty of a factor of two both ways. The list of non detec-
tions is given in Table A.1.
Table A.1. Source list, spectral types, and 63.32 µm o-H2O line fluxes.
Name SP. Type o − H2O flux
– – 10−17
W/m2
Anon 1 M0 <1.17
BP Tau K7 <0.94
CIDA2 M5.5 <0.89
CI Tau K7 <0.92
CoKu Tau/4 K3 <1.37
CW Tau K3 <1.26
CX Tau M2.5 <0.94
CY Tau M1.5 <1.41
DE Tau M1 <1.23
DF Tau M2 <1.28
DG Tau K6? <1.32
DG Tau B <K6 <1.25
DH Tau M1 <1.07
DK Tau K6 <0.53
DL Tau K7 <1.14
DM Tau M1 <0.89
DN Tau M0 <0.77
DO Tau M0 <1.21
DP Tau M0.5 <0.92
DQ Tau M0 <0.98
DS Tau K5 <0.58
Appendix B: Location of emission for H2O lines
0.1 1.0 10.0 100.0
r [AU]
0.0
0.1
0.2
0.3
0.4
z/r
AV=1
AV=1
AV=1
AV=10
AV=10
15.738µm
63.324µm
89.988µm
269.27µm
0 2 4 6 8 10
log nH2O
[cm-3
]
Fig. B.1. Location of the H2O emission for a typical disc model (M∗ =
0.8 M⊙, L∗ = 0.7 L⊙, Teff = 4400 K, UV excess fUV = 0.01,
X-ray luminosity LX = 1030
erg s−1
, Rin = 0.1 AU, Rout = 300 AU,
Mdisc = 0.01 M⊙, dust/gas = 0.01, ϵ = −1, scale height H0 = 1 AU at
Riviere-Marichalar et al. 2012, ProDiMo prediction
Temperature
Wavelength
Spitzer
Hot PACS
Warm PACS
HIFI

SMA observations
• Test interpretation: warm
inner disk, or outflow/wind?
• Targets: brightest 63 mu
emitters
• Observed on Dec 18, 2013
compact configuration (2”
beam ~ 300 AU) @ 321 GHz
Table 2. Probabilities for correlations between o-H2O line intensity
stellar/disc parameters.
Observable Points n Spearman’s prob. Kendall’s prob.
L[OI] 68 0.0009 (0.4090) 0.0000 (0.196)
63 µm flux 64 0.0147 (0.2635) 0.0002 (0.4567)
850 µm flux(2)
57 0.0145 (0.2596) 0.0131 (0.8496)
Lstar
(3)
65 0.1789 (0.1130) 0.1980 (0.5535)
LX
(3)
65 0.0225 (0.9912) 0.0087 (0.6012)
α(2−8 µm) (4)
62 0.026 (0.1547) 0.0023 (0.3850)
L[OI]6300 Å 27 0.1291 (0.3255) 0.1008 (0.3450)
Notes. The values obtained for random populations are shown in br
ets. Accurate only if N > 30. (2) 850 µm continuum fluxes f
Andrews & Williams (2005). (3) Values from Güdel et al. (20
(4) SED slope from Luhman et al. (2010).
Fig. 2. Plot of the 63.32 µm o-H2O line luminosity ve
[OI] 63.18 µm. Filled dots are detections, arrows are upper limits. S
dark grey arrows represent objects with non-detections spanning
same spectral range as the objects with detections. Light grey, em
arrows represent non-detections with other spectral types.
other abundant species emit strongly at or close to the obser
Riviere-Marichalar et al. 2012

HL Tau: recent headliner
• Quiescent disk, main accretion phase done?
• Or what???

SMA data
• H2O detected at 5σ
(single beam), 8σ
integrated, toward HL
Tau
• Matches disk position,
tentative (3-4σ)
extended emission
• Proﬁle: blue-shifted
(-15 km/s) and broad
(20 km/s)!
Kristensen et al. in prep.
40 20 0 20 40
Velocity (km s 1)
0.05
0.00
0.05
0.10
0.15
0.20
0.25
Fluxdensity(Jy)
13CO
v = 1–0
H2O
102,9–93,6
Outﬂow
Disk

Vibrational CO: wind
• 4.7 mu rovibrational emission
from CO supports wind
hypothesis
• Identical line proﬁles, within
uncertainty
• CO emission unresolved at 0.2”
resolution (30 AU)
Herczeg et al. 2011
40 20 0 20 40
Velocity (km s 1)
0.05
0.00
0.05
0.10
0.15
0.20
0.25
Fluxdensity(Jy)
13CO
v = 1–0
H2O
102,9–93,6

Excitation conditions
• Use 321 GHz and 63 mu
lines to estimate
excitation conditions, n,
T, N(H2O)
• Highly degenerate
• N(H2O) ~ 1019 cm-2,
n(H2) ~ 109-1012 cm-3,
T ~ 500-1500 K,
r(H2O) ~ 2 AU
5 6 7 8 9 10 11 12
log n (cm 3)
16
17
18
19
20
logN(o-H2O)(cm2)
Masing
RM12
log(321 GHz / 63µm)
-3
-3
-2
-2
-1
0
1
5 6 7 8 9 10 11 12
log n (cm 3)
0
2
4
6
8
10
Emittingradius(AU)
Same emitting region
Different emitting region

Molecular protostellar winds
• Model calculations show molecules
survive launching in MHD winds
• Physical conditions in wind close to
what is inferred from radiative transfer
A&A 538, A2
-50 0 50
0
50
100
150
cylindrical radius (AU)r0
height(AU)z
Fig. 1. Overall geometry of the “slow” MHD disk wind solution of
(Casse & Ferreira 2000) used in this article. Solid white curves show
various magnetic ﬂow surfaces, with that anchored at 1 AU shown in
dashed. The density for ˙Macc = 10−6
M⊙/yr and M⋆ = 0.5 M⊙, is coded
in the contour plot starting at 8 × 104
cm−3
and increasing by fac-
tors of 2. The bottom dotted line traces the slow magnetosonic surface
(at 1.7 disk scale heights) where our chemical integration starts.
in
ad
un
nu
si
st
d
d
d
d
d
H
(3
tio
pe
ch
vo
vo
as
an
ot
tr
in
M
–
–
–
–
–
Panoglou et al. 2012
D. Panoglou et al.: Molecules in protostellar MHD disk winds. I.
102
103
104
10-3
10-2
10-1
100
101
102
103
T(K)
z (AU)
a
class 0
class I
class II
10
6
108
10
10
10-3
10-2
10-1
100
101
102
103nH(cm-3
)
z (AU)
b class 0
class I
class II
10-3
10-2
10-1
10
0
101
102
10-3
10-2
10-1
100
101
102
103
Av
z (AU)
c class 0
class I
class II
10
-2
10
-1
10
0
10
1
10
2
10
3
10
-3
10
-2
10
-1
10
0
10
1
10
2
10
3
poloidalvelocity(km/s)
z (AU)
bulk
drift
d
class 0
class I
class II
10
-15
10-14
10
-13
10-12
10
-11
10-10
10
-9
10-8
10
-7
10
-3
10
-2
10
-1
10
0
10
1
10
2
10
3
ζ(H2
+
)(s-1
)
z (AU)
e
class 0
class I
class II
10
-6
10
-4
10-2
10
0
10
2
104
10
6
10
8
10
-3
10
-2
10
-1
10
0
10
1
10
2
10
3
χe
-3Av
z (AU)
f
10
-5
10
-4
10-3
10-2
n(ions)/nH
g
-4
10
-3
10-2
10
-1
100
n(H2)/nH
h
10
-8
10
-7
10-6
10-5
10-4
n(CO)/nH
i

Wind solution: a match
• N(H2O) / N(CO) ~ 1
• Model predictions reproduce observations: wind origin
D. Panoglou et al.: Molecules in protostellar MHD disk winds. I.
10
-7
10
-6
10
-5
10-4
10
-2
10
-1
10
0
10
1
10
2
10
3
n(A)/nH
z (AU)
class 0
10
-7
10
-6
10
-5
10-4
10
-2
10
-1
10
0
10
1
10
2
10
3
z (AU)
class I
10
-7
10
-6
10
-5
10-4
10
-2
10
-1
10
0
10
1
10
2
10
3
z (AU)
class II
X(H2O)
X(OH)
X(O)
X(SO)
X(CO)
X(C)
X(S)
ig. 11. Abundances relative to H nuclei of important O, C, and S-bearing species along a flow line launched at 1 AU, for our Class 0 (left), Class I
middle) and Class II models (right).
2O: when the wind temperature exceeds ≃400 K, oxygen not
cked in CO is converted to H2O through the endothermic reac-
ons of O and OH with H2 in Eqs. (43), (44). Together with
3O+
recombination, this reaction is efficient enough to bal-
nce the water destruction processes active in Class I/II jets
discussion in Sect. 3.1.3). Accurate H2 abundances on these in-
ner streamlines await a detailed non-local treatment of H2 shield-
ing, not taken into account in the present preliminary approach
For the same reason, we do not present results at r0 > 1 AU for
the Class II jet, but we note that the effect of increasing r0 will be

Part III
Low-mass protostars in
high-mass clusters

Stars form in clusters
But how do low-mass stars form in
the presence of high-mass stars?Cygnus X, Herschel
Hennemann & Motte

Outﬂows scale with Menv
• Idea: Outﬂows provide a low-contrast
tracer of low-mass population in clusters
100
101
Lbol[L⊙]
10−6
10−5
10−4
10−3
FCO(6−5)[M⊙kms−1
yr−1
]
Class 0
Class I
10−1
100
101
Menv[M⊙]
10−4
10−3
MCO (
e.g.Yildiz,Kristensenetal.2015

Recipe
• Step I: Build a  
cluster-in-a-box
• Step II: Measure outﬂow
emission from nearby
low-mass clouds
• Step III:Assign emission
to cluster members
• Step IV: Observe 2 1 0 1 2
x (pc)
2
1
0
1
2
y(pc)
0.1 M
1 M
10 M
30 M
2 1 0 1 2
log(M) (M )
0
1
2
3
log(dN/dM)
Kristensen & Bergin (to be subm.)
ALMA observations: Higuchi et al. 2015, IRAS16547

Recipe
cluster-in-a-box
low-mass clouds
to cluster members
• Step IV: Observe
050100150200250300
Da (arcsec)
150
100
50
0
50
100
Dd(arcsec)
IRAS2A-West
IRAS2A-East
IRAS4A-North
IRAS4A-South
IRAS4B-Total
0
2
4
6
8
R
TMBdv(Kkms1)
CH3OH emission traces outﬂows

Recipe
cluster-in-a-box
low-mass clouds
to cluster members
20 10 0 -10 -20
Offset (arcsec)
20
10
0
-10
-20
Offset(arcsec)
Model
0
0.2
0.4
0.6
0.8
1.0
Jykms1beam1
20 ALMA
0.8
1.0

Recipe
cluster-in-a-box
low-mass clouds
to cluster members
20 10 0 -10 -20
Offset (arcsec)
-10
-20
Offset
0
0.2
0.4
Jykms
20 10 0 -10 -20
Offset (arcsec)
20
10
0
-10
-20
Offset(arcsec)
ALMA
0
0.2
0.4
0.6
0.8
1.0
Jykms1beam1
0.4
0.5
m1)
Model
Observations

Benchmarking model
• Observations contain hot core,
high-mass outflow, low-mass
outflows
• Radial average matches at 50%
• Toy model reproduces
observations: fine-tuning required
20 10 0 -10 -20
Offset (arcsec)
20
10
0
-10
-20
Offset(arcsec)
Model
0
0.2
0.4
0.6
0.8
1.0
Jykms1beam1
20 10 0 -10 -20
Offset (arcsec)
20
10
0
-10
-20
Offset(arcsec)
ALMA
0
0.2
0.4
0.6
0.8
1.0
Jykms1beam1
0 5 10 15 20
Distance (arcsec)
0
0.1
0.2
0.3
0.4
0.5
Intensity(Jykms1beam1)
Model
Observations
5 6 7 8 9 10
0.00
0.01
0.02
0.03
0.04
0.05

Next steps
• Include contribution from
high-mass outflows
• Explore parameter space:
cluster age, IMF, cluster
mass, …
• Other species: H2O, high-J
CO as unique shock tracers
• Extrapolate to high-z
starburst galaxies
f rms noise in the integrated spectrum at ∆ν = 40 MHz.
g Observed integrated continuum flux density.
h Observed integrated line flux.
i Modeled integrated line flux.
j Center velocity of fitted Gaussian relative to z = 3.911.
k Full width at half-maximum of fitted Gaussian.
l Using z = 3.911, H0 = 70 km s−1 Mpc−1
, ΩΛ = 0.73, and Ωtot = 1.
m Not corrected for lensing.
n Upper limit from Wagg et al. (2006).
et al. (2009b). With CO lines detected from rotational levels up
to J = 11 (Weiß et al. 2007; Riechers et al. 2009a) and HCN,
HNC, and HCO+
lines from levels up to J = 6 (Wagg et al. 2005;
Garc´ıa-Burillo et al. 2006; Riechers et al. 2010), its molecular
medium has been characterized very well. Analysis of the CO
rotational ladder revealed unusually high excitation (Weiß et al.
2007). However, a previous search for the ortho ground-state
11,0–10,1 H2O line (upper level energy Eu/k = 61 K) was
unsuccessful (Wagg et al. 2006). We therefore targeted lines of
higher excitation, with Eu/k from 101 to 454 K.
2. OBSERVATIONS AND RESULTS
We used the Institut de Radioastronomie Millimétrique
(IRAM) Plateau de Bure Interferometer (Guilloteau et al. 1992)
with six antennas in 2010 December and 2011 February to ob-
serve the four H2O lines listed in Table 1 (which also lists all
relevant observational parameters) in APM 08279+5255. Ob-
serving times (including overheads) varied from 2 to 5.2 hr per
line. The WIDEX back end was used, providing 3.6 GHz instan-
taneous bandwidth in dual polarization. Data reduction using the
GILDAS package included the standard steps of data flagging,
amplitude, phase and bandpass calibration, and conversion into
datacubes. The flux density scale is accurate to within 15%. The
datacubes were deconvolved using a CLEAN algorithm (Clark
1980).
All four lines were detected and an image of the flux
distribution of the 21,1 − 20,2 line is shown in Figure 1. Fits
to the continuum uv-data were used to calculate the continuum
fluxes (reported in Table 1) and source sizes. In the high angular
Figure 1. H2O emission from APM 08279+5255. The contoured pseudocolor
map shows the distribution of the velocity-integrated continuum-subtracted
H2O 21,1 − 20,2 line flux, with contour levels of 3σ, 5σ, 7σ, and 9σ, where
σ = 0.5 Jy km s−1 beam−1
. The dashed white ellipse indicates the synthesized
beam. The inset presents the NICMOS F110W image (Ibata et al. 1999) and
shows that the gravitationally lensed images (the brightest of which are 0.′′378
apart) are fully covered by the synthesized beam.
(A color version of this figure is available in the online journal.)
spatially resolved, with source sizes of approximately 0.′′
5,
in agreement with high-resolution observations of the 1 mm
continuum (Krips et al. 2007), and CO 1−0 (Riechers et al.
2009b). Integrated spectra of the four H2O lines are shown in
The Astrophysical Journal Letters, 741:L38 (5pp), 2011 November 10
van derWerf et al. 2011
H2O emission at z=3.911

Conclusions
• Water traces shocks in protostars: mass less
important than evolution
• Hot water toward HL Tau originates in wind, not
inner disk: implications for hot water in disks?
• Cluster-in-a-box models provide access to low-mass
populations in embedded high-mass clusters

Colloquium given at NASA/JPL

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