Water in NGC 6334 IM. Emprechtinger, D. Lis, P. Schilke, R. Rolffs, R. Monje, The Chess Team

NGC 6334 ID=1.7 kpcM=200 M

Four embedded cores with 3-60 M

SMA 1 and SMA 2 emit rich and complex spectra

1.3 mm continuum taken from Hunter et al. 2006

HIFI Observations All Bands except 6a have been observed

Emission lines of ~35 molecules + isotopologues identified

Strong CH3-O-CH3 and

methanol lines.

Water in NGC6334 IH2

16O: 16 lines detected. 8 lines of p-H2O and 8 lines of o-H2O. Elower= 0-880 K.

6 H218O lines (3 ground state transition+ 3

excited lines)6 H2

17O lines (3 ground state transition+ 3 excited lines)

Four HDO lines (111-000 in absorption + 3 emission lines.

In total 32 lines of water detected.

Individual Components

Main component: vlsr=6-8 km/s, FWHM= 5 km/s

Foreground components @ 0, +6 and +8 km/s, seen in H2

16O ground state transitions.

Two outflow components (broad and narrow outflow)

Foreground ComponentsCold foreground(?):

Tex of o-H2O = 6.5K.

excitation has to be considered for H2O 110-101

Using HF to determine the H2 column

density of FG clouds

x(H2O)=5x10-8 - in agreement with

models.

Previously reported o/p ratio of 2, based on the H2O 110-101 & 111-000

line is too low. Including H2O 212-101

leads to o/p ratio of 3

Outflow: Broad outflowH2

17O

H218O

H216O

H217O

HDO

H216O is optically very thick (τ>300);

only a small fraction (15%) of the continuum subject to absorption.

x(H2O)=4x10-5, based on H218O & CO

data. Desorption of water ice by sputtering.

H218O/H2

17O = 3.7(0.6) (= elemental 18O/17O ration)

HDO/H2O=2x10-4

Abundances agree with predictions of warm (>100 K) gas.

Outflow: Narrow outflow Narrow outflow as not

been detected so far Narrow outflow detected

in excited lines. Hot outflow is optically

thick (=2.5-80). Model with LVG code

(Radex): Tkin=100 K

n=3e7 cm-3

202-111321-303

211-202 220-211

Dense Cores: H216O

422-413

422-331

524-431

624-717 Hot Core lines:Eup>400 K

vLSR=-8.1

km/s(most likely associated

with SMA 2)

Five “hot core” lines detected. All but one show potential maser activity.

Dense Cores: Rare isotopologues Dense core lines identified by velocity (-8.1 km/s), all excited lines of H2

18O, H217O, and

HDO are coming from the dense core

H218O/H2

17O=1.2-2 ⇒ (H2

17O)=0.52-1.4

H218O much weaker than

corresponding H216O line

⇒ Dense core is embedded in lower density envelope.

H218O 211-202

H217O 211-202

Dense Cores: Rare isotopologues

Modeling lines assuming LTE (XCLASS), assuming a source size of 4’’

Isotop. Temp. Col. Density

H218O 43 K 3.6 x 1015 cm-2

H217O 50 K 8 x 1014 cm-2

HDO 50 K 4 x 1014 cm-2

Comparing H218O column density with core mass results in

x(H2O)=10-6, 100 times lower than expected.

HDO/H2O=3x10-4 similar to the value found in the outflow.

Ratran Model Source model based on the model by Rolffs et al. 2011. Power-law density density and self consistent temperature profile.

Non spherical outflow feature which covers parts of the source is added.

Water abundances of 3 x 10-9 (T<100 K) and 6.0 x 10-7 (T>100 K).

Outflow: Tkin=70-120 K

n=1e5 cm-3

Ratran Model-Para H2O

Ratran Model-Ortho H2O

SummaryH2O abundance in cold gas and outflow as predicted by

chemical models. In hot cores the water abundance is by a factor 100 to low.

Ortho/Para ratio is everywhere close to the statistical value of three.

Second narrow outflow component was detected.

H218O and H2

17O abundances are as expected from 18O and 17O

abundances.

HDO/H2O = 10-4 in the outflow and the hot core. Almost all water

we see is formed in warm gas.