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

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

Background Discovery: Snyder & Buhl 1972 in SGR B2.

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

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

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

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.

Analysis Data & Source selection:

Analysis Dust Temperature & H2 column density

Analysis Example: AGAL351.444+00.659 HNCO

Analysis Example: AGAL351.444+00.659

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

Analysis N-bearing species: HC3N HNC N2H+

Analysis C-bearing species: 13CS C2H H13CO+

Analysis SiO:

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

Analysis

Analysis Example: MSXDC G331.71+00.59 MSX A band Spitzer APEX (870 um)

Analysis Example: MSXDC G331.71+00.59 HNCO SiO

Analysis Example: MSXDC G331.71+00.59

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