1. TURBULENCE AND HEATING OF MOLECULAR CLOUDS IN THE GALACTIC CENTER: Natalie Butterfield (UIowa) Cornelia Lang (UIowa) Betsy Mills (NRAO) Dominic Ludovici (UIowa) Physical Properties of G0.25+0.01

2. Molecular Clouds in the GC Strong tidal forces from central BH High temperatures (50- 300K) compared to the disk (10-20K) 1 – Densities typically higher Large velocity dispersions 2 – Large turbulence Interaction of the ISM with the strong magnetic field lines 3 – Radio Arc 1 Huttemeister et al. 1993, Mauersberger et al. 1986 2 Bally et al. 1987 3 Morris & Yusef-Zadeh 1989 Brick Sgr-A* Sgr-B 25 pc

3. Many recent studies on G0.25+0.1 (Brick) Extremely massive and dense 1 – Mass: M Dust ~ 1.3 x 10 5 M  – Small Radius: ~ 2.8 pc – Density: 7.3 x 10 4 cm -3 Young Cloud 2 – SiO Shocks  Cloud-Cloud Collision Precursor to Arches-like massive cluster 3 Gas temperature > dust temperature (~20 K 1 )  cloud-cloud collision Shell like structure from cloud collision 4 Kauffmann et al. 2013 1 Longmore et al. (2012) 2 Kauffmann et al. 2013 (SMA/CARMA) 3 Rathborne et al. (in prep) ALMA 4 Higuchi et al (2014) ALMA

4. Overview Observational Summary – Taken January 2012 with the VLA, DnC array – Continuum + Spectral Lines – 1.5 km/s spectral resolution – 1.5 arcsec resolution Multiple transitions of NH 3 : (1,1)-(9,9) 36 GHz Class I CH 3 OH (4-3) maser – 2 bands (K ~25GHz, Ka ~36GHz) Science Questions – What is the velocity structure of the Brick? – What is the gas temperature of the Brick? – Do we observe any other tracers that could tell us about the heating Brick?

5. Distribution of NH 3 in the Brick The cloud is abundant in NH 3 Two curved arc-like structures Brightest emission is in the south Very good velocity resolution (~1.5km/s) – Allows us to do detailed kinematics Maximum intensity (moment 8) distribution of NH 3 (3,3)

6. Velocity & Velocity Dispersion Complicated structure 2 streams of gas – ~10 km/s – ~35 km/s Highest velocity dispersions in the North Average velocity dispersions of ~10 km/s

7. Spectral Analysis Multiple velocity components – Resulting in large velocity dispersions Regions along inner arc have wider velocity dispersions – ~15 km/s

8. NH 3 (3,3) Line Emission starts near the top of the cloud Smoothly ripples down to the southern part of the cloud

9. Position vs. Velocity Two streamers of gas Higher velocity cloud and lower velocity cloud converge in the south Position vs. Velocity diagram of the NH 3 (3,3) line

10. Temperature Temperatures calculated from the (3,3) to (6,6) line Rotational gas temperature of the cloud is ~95 K Gas temperature for the Brick is much hotter than clouds in the Disk

11. Masers ~80 36 GHz Class I Methanol masers 30 have brightness temperatures > 1000K Majority of the masers are in the South Traces shocked gas -> cloud- cloud collisions Consistent with SiO detections

12. Comparison of CH 3 OH Maser to the Velocity and NH 3 The CH 3 OH masers also fall along a similar curve in the velocity structure and regions with broader lines The 36 GHz CH 3 OH masers trace a similar structure of the NH 3 Majority of the masers fall along the brightest NH 3 regions

13. Comparison of CH 3 OH Maser to the Velocity and NH 3 The CH 3 OH masers also fall along a similar curve in the velocity structure and regions with broader lines The 36 GHz CH 3 OH masers trace a similar structure of the NH 3 Majority of the masers fall along the brightest NH 3 regions

14. Is the Ammonia Masing? Betsy Mills

15. Is the Ammonia Masing? Betsy Mills

16. Similar conditions in other GC clouds G0.10-0.08 – Bright in NH 3 – ~50 36 GHz CH 3 OH Masers – Similar to the Brick, these also trace the NH 3 NH 3 (3,3) with CH 3 OH maser contours CH 3 OH maser1.1 mm (CSO), 20cm (VLA), 8 μm (Spitzer) Adam Ginsburg Brick G0.10-0.08

17. Conclusion What is the velocity structure of the Brick? – Very complex structure with two streams of gas, converging in the south. What is the gas temperature of the Brick? – Rotational gas temperatures of ~95 K, consistent with other molecular clouds in the Galactic Center Do we observe any other tracers that could tell us about the heating Brick? – Yes, we detect ~80 CH 3 OH masers  Shock tracer Preliminary analysis suggest that other clouds in the GC show similar properties. – Abundant CH 3 OH masers and NH 3 in G0.10-0.08 cloud

18. Thank you!

19. HC 3 N Dense cores in both clouds

20. How to use NH 3 to get Temperature What do you do? 1.Convert from Jy/beam * km/s  K * km/s 2.Calculate the corrected column density 3.Calculate the (rotational) temperature

21. Hyperfine Structure in the (1,1) and (2,2) lines Ratio of satellite lines to the main line give limits on the optical depth – Optically Thin: large intensity of main peak to satellites – Optically Thick: All lines are about the same intensity Optically ThinOptically Thick

22. G0.25+0.01 Continuum (25 GHz) What do we see? – Weak emission – 2 point sources – Large diffuse region Tangential filament – Several clumps Several extended features may be resolved out Rms: 0.035 mJy/beam Beam size: 1.87” Largest angular size: 66” 1 arcmin1 parsec

23. Do we detect any Methanol Masers? Yes! We see the 36 GHz Maser Betsy Mills

24. Origin of 36 GHz Methanol Masers? What does the max map tell us? – Majority are in the southern cloud Class I or Class II – Shocked gas from collisions – Consistent with Kauffmann et al 2013 Previously only one H 2 O maser known (Lis et al. 1994)