1. Hwihyun Kim IGRINS Science Workshop November 12-13, 2015 Collaborators: John Lacy & Dan Jaffe

2.  Reflection nebulae at D=830pc  3-4 HII regions in the center embedded in molecular clouds  Mon R2 Core  Ultra compact HII region  Surrounded by several PhotoDissociation Regions (PDRs) ~15’x15’ JHK composite of SQUID images at KPNO 1.3m (Carpenter et al. 1997)

3.  Mon R2: closest Ultra Compact HII (UCHII) Region  Diameter=24” or 0.1 pc (measured using 12.8μm [Ne II] map)  n(H 2 )= a few 10 5 -10 6 cm -3  IRAS 1SW: main ionizing source, B0 to O9.5 type

4.  Morphology: cometary, core-halo, shell, irregular, and multiple peaks (Wood & Churchwell, 1989).  Lifetime “problem”: If UCHII regions are classical pressure-driven spherical shells (V exp ~10km/s), they should remain compact only for ~10 4 yr.  HOWEVER most of detected UCHII regions are ~10 5 yr old!

5.  of 16 UCHII regions with TEXES at IRTF suggest  UCHII region morphologies are the same: systematic surface flows, rather than turbulence or bulk expansion  Significant velocity gradients (~5-20 km/s)  Limb-brightened: up against dense neutral gas  these wind-driven cometary shells could have much longer lifetime  Need to find the evidence for dense molecular gas along the shell wall!  Are they moving along with the ionized gas? Or, slowly expanding?

6.  Dec 29, 2014  2x300sec exposure on each slit position (6 pointings)  Slit off-on-on-off mode IGRINS H & K Spectra Total 600 sec

7. IGRINS PLP-2.1-alpha.2 by Jae-Joon Lee Plotspec by Kyle Kaplan

8. H2 Br γ [Fe III]He I

9. H2 Br γ [Fe III]He I

10. H2 Br γ [Fe III]He I

11. H2 Br γ [Fe III]He I

12. H2 Br γ [Fe III]He I

13. H2 Br γ [Fe III]He I

14. H2 [Fe III] He I Br γ -100km/s 100km/s

15. IRAS1-Center 1300K

16. IRAS1-SE1 1300K

17. IRAS1-SE2 1300K

18. IRAS1-SE3 1300K

19. IRAS1-SE4 1300K

20. IRAS1-SE5 1300K

21.  IGRINS spectra clearly show emissions both from ionized and neutral gases.  Position-Velocity diagrams of ionized gases indicate that they flow along the cavity walls (Δv = 39.906±2.203 km/s).  No obvious motion (Δv = 10.026±0.134 km/s) is present in the H 2 emission lines, indicating that there is little or no entrainment of the molecular gas by the ionized gas flow. => need to be confirmed with the complete map!