Presentation is loading. Please wait.

Presentation is loading. Please wait.

M. Emprechtinger, D. Lis, P. Schilke, R. Rolffs, R. Monje, The Chess Team.

Similar presentations


Presentation on theme: "M. Emprechtinger, D. Lis, P. Schilke, R. Rolffs, R. Monje, The Chess Team."— Presentation transcript:

1 M. Emprechtinger, D. Lis, P. Schilke, R. Rolffs, R. Monje, The Chess Team

2 NGC 6334 I D=1.7 kpc M=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

3 HIFI Observations All Bands except 6a have been observed Emission lines of ~35 molecules + isotopologues identified Strong CH 3 -O-CH 3 and methanol lines.

4 Water in NGC6334 I H 2 16 O: 16 lines detected. 8 lines of p-H 2 O and 8 lines of o-H 2 O. E lower = 0-880 K. 6 H 2 18 O lines (3 ground state transition+ 3 excited lines) 6 H 2 17 O lines (3 ground state transition+ 3 excited lines) Four HDO lines (1 11 -0 00 in absorption + 3 emission lines.  In total 32 lines of water detected.

5 Individual Components Main component: v lsr =6-8 km/s, FWHM= 5 km/s Foreground components @ 0, +6 and +8 km/s, seen in H 2 16 O ground state transitions. Two outflow components (broad and narrow outflow)

6 Foreground Components Cold foreground(?): T ex of o-H 2 O = 6.5K.  excitation has to be considered for H 2 O 1 10 -1 01 Using HF to determine the H 2 column density of FG clouds x(H 2 O)=5x10 -8 - in agreement with models. Previously reported o/p ratio of 2, based on the H 2 O 1 10 -1 01 & 1 11 -0 00 line is too low. Including H 2 O 2 12 -1 01 leads to o/p ratio of 3

7 Outflow: Broad outflow H 2 17 O H 2 18 O H 2 16 O H 2 17 O HDO H 2 16 O is optically very thick (τ>300); only a small fraction (15%) of the continuum subject to absorption. x(H 2 O)=4x10 -5, based on H 2 18 O & CO data. Desorption of water ice by sputtering. H 2 18 O/H 2 17 O = 3.7(0.6) (= elemental 18 O/ 17 O ration) HDO/H 2 O=2x10 -4 Abundances agree with predictions of warm (>100 K) gas.

8 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): T kin =100 K n=3e7 cm -3 2 02 -1 11 3 21 -3 03 2 11 -2 02 2 20 -2 11

9 Dense Cores: H 2 16 O 4 22 -4 13 4 22 -3 31 5 24 -4 31 6 24 -7 17 Hot Core lines: E up >400 K v LSR =-8.1 km/s (most likely associated with SMA 2) Five “hot core” lines detected. All but one show potential maser activity.

10 Dense Cores: Rare isotopologues  Dense core lines identified by velocity (-8.1 km/s), all excited lines of H 2 18 O, H 2 17 O, and HDO are coming from the dense core  H 2 18 O/H 2 17 O=1.2-2 ⇒  (H 2 17 O)=0.52-1.4  H 2 18 O much weaker than corresponding H 2 16 O line ⇒ Dense core is embedded in lower density envelope. H 2 18 O 2 11 -2 02 H 2 17 O 2 11 -2 02

11 Dense Cores: Rare isotopologues Modeling lines assuming LTE (XCLASS), assuming a source size of 4’’ Isotop.Temp.Col. Density H 2 18 O43 K3.6 x 10 15 cm -2 H 2 17 O50 K8 x 10 14 cm -2 HDO50 K4 x 10 14 cm -2  Comparing H 2 18 O column density with core mass results in x(H 2 O)=10 -6, 100 times lower than expected.  HDO/H 2 O=3x10 -4 similar to the value found in the outflow.

12 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).  Outflow:T kin =70-120 K n=1e5 cm -3

13 Ratran Model-Para H 2 O

14 Ratran Model-Ortho H 2 O

15 Summary  H 2 O 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.  H 2 18 O and H 2 17 O abundances are as expected from 18 O and 17 O abundances.  HDO/H 2 O = 10 -4 in the outflow and the hot core. Almost all water we see is formed in warm gas.


Download ppt "M. Emprechtinger, D. Lis, P. Schilke, R. Rolffs, R. Monje, The Chess Team."

Similar presentations


Ads by Google