1. Circumnuclear Disk, Sagittarius A* & the NAC experience
By Kevin Gima (University of Maryland, College Park)
Mentor: Dr. Elisabeth Mills (NRAO)
Collaborator: Viviana Rosero (NMT & NRAO)

2. Background
Sagittarius A* (Sgr A*): supermassive black hole at the center of our galaxy (8 kpc) (Montero-Castaño et al. 2009)
Sgr A* mass: 4.1x106 M⊙ (Ghez et al. 2008)
Circumnuclear disk (CND): gas disk 2-3 parsecs from Sgr A* (6-9 light years) (Montero-Castaño et al. 2009)
Radio continuum
HCN
Montero-Castaño et al. 2009

3. This Work Determine kinematic temperatures in the CND
Star formation happening within the clouds?
Determine what will happen with the material around the black hole.

4. Regions Upper Cloud Lower Cloud CH3CCH Christopher and Scoville 2005
Recombination
Lower Cloud
Christopher and Scoville 2005

5. Preliminary Results: Upper Cloud
CH3CCH 6-5
CH3CCH 15-14
CH3CCH 16-15

6. Preliminary Results: Lower Cloud
CH3CCH 15-14
CH3CCH 16-15

7. Discussion Data fitted well with single temperature model
One of the better results for CND temperature to date
No detection of CH3CN might indicates that these regions are not heated by a protostar

8. Pro: Imposter Syndrome Workshop
Learned to appreciate my own accomplishments
Learned to live by my own standards, not anyone else’s
Consider having more than one workshop for this

9. Cons: Research can be very painful!
It can be frustratingly slow; could be banging head for days & days!!!
Initially I was grossly incompetent; I still am!!!

10. Conclusion NAC Socorro was a time of personal growth for me
Stepped outside of comfort zone (lived with family for most of life)
Learned how manage things on own
Learned how to better cope with stress & anxiety
THANK YOU NAC!!!
Any Questions??????????????????????????????

11. Extra Slide: Equation

12. Extra Slide: Previous Work
Mass of CND:
104 M⊙ from dust and CO analysis (Requena Torres et al. 2012)
M⊙ from gas tracers (Requena Torres et al. 2012)
Density of CND:
8x107 cm-3 needed to survive tidal forces of Sgr A* (Christopher et al. 2005)
HCN & HCO+ give estimates of 107 & 108 cm-3 (Christopher et al. 2005)
Could be strong enough to withstand tidal forces

13. Extra Slide: Observations
ALMA Band 3 ( GHz) &
Band 6 ( GHz)
Source: spectrum.ieee.org/tech-talk/aerospace/astrophysics/alma-makes-a-highprofile-debut
ALMA Cycle 2 Observations
Resolution: 1-3 km/s
CH3CCH (6-5),(15-14),(16-15)
HC3N (10-9),(11-10),(28- 27),(30-29)
CH3CN (5-4), (6-5), (14- 13),(13-12),(12-11) None detected

14. Extra Slide: Method Spectra extracted using CASA Moment maps
Made Gaussian fit using CLASS
Full width half max (FWHM), position, and peak antenna temperature (amplitude) extracted from fit
Line frequency and excitation energies obtained from Splatalogue
All lines fitted to K=3 to prevent nonphysical solutions
Temperature = -1/slope
K=1, 0
K=3
K=2
K=4

15. Extra Slide: Preliminary Results: Gaussian Fits
Upper Cloud
CH3CCH 6-5
CH3CCH 15-14
CH3CCH 16-15
Lower Cloud

16. Extra Slide: Future Work
Regions where HC3N is most prominent have been identified
HC3N analysis will give us further information on the mass and density of the clouds.
Heating mechanism
Are the conditions right to form stars in these two regions?