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) 07.29.15

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

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.

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

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

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

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

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

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!!!

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??????????????????????????????

Extra Slide: Equation

Extra Slide: Previous Work Mass of CND: 104 M⊙ from dust and CO analysis (Requena Torres et al. 2012) 105 - 106 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

Extra Slide: Observations ALMA Band 3 (84-116 GHz) & Band 6 (211-275 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

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

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

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?