1. HNCO: A Molecule Traces Low-velocity Shocks
喻耐平
王俊杰 研究员
中国科学院国家天文台

2. Content
1. Background;
2. Data analysis;
3. Summary.

3. Background
Discovery: Snyder & Buhl 1972 in SGR B2.

4. Background Circumstellar envelopes around AGB stars：
Prieto et al. 2015

5. Background HNCO & SiO (Zinchenko et al. 2000):
HNCO abundances enhanced by shocked gas.

6. Background
HNCO & C18O，HC3N (Li et al. 2013):

7. Background HNCO & C18O，HC3N (Li et al. 2013):
1. HNCO is produced in a warm environment；
2. Shock could enhance the HNCO abundance；
3. A good correlation between HNCO and HC3N.

8. Analysis
Data & Source selection:

9. Analysis
Dust Temperature & H2 column density

10. Analysis
Example: AGAL
HNCO

11. Analysis
Example: AGAL

12. Analysis Column densities and Abundances: HNCO,HC3N,13CS,SiO C2H,N2H+
HCO+,H13CO+,HNC,HN13C

13. Analysis
N-bearing species:
HC3N
HNC
N2H+

14. Analysis
C-bearing species:
13CS
C2H
H13CO+

15. Analysis
SiO:

16. Analysis FWHM: traces low-velocity shocks
△V(HN13C) < △V(HNCO) < △V(SiO)
HN13C
SiO

17. Analysis

18. Analysis
Example: MSXDC G
MSX A band
Spitzer
APEX (870 um)

19. Analysis
Example: MSXDC G
HNCO
SiO

20. Analysis
Example: MSXDC G

21. Summary
The abundance of HNCO has a good relationship with N-bearing species.
HNCO traces low-velocity shocks.
Fast-velocity shocks may destroy HNCO.