1. SWAN: Survey of Water & Ammonia in Nearby Galaxies
Mark Gorski, Jürgen Ott, Richard Rand, David Meier, Emmanuel Momjian, Fabian Walter, Eva Schinnerer

2. Contents
What is SWAN?
Results
NH3
Masers
Conclusion

3. Galaxy Sample Galaxy D[MPC] SFR [M yr -1] Comments IC 342 3.0 1.5
Face on spiral
NGC 6946
5.2
1.4
Face on spiral, buried nuclear SF
NGC 253
3.5 5
Barred spiral, nucleated starburst
NGC 2146
3.9 11
Peculiar barred spiral, LIRG(almost)
SSRO/PROMPT/CTIO
Range of SFR magnitudes. SFR here refers to nuclear starburst.
IC 342 Is a milky way analog
Star formation rates exceed that of the milky way in a sub region of these galaxies
Brightest, more appropriate is fluxiest, galaxies. As a side note, for future studies, these galaxies span a range of SFR to use as templates to study High redshift galaxies.
Laura Z. Working on Arp 220
T.A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF; Gemini Observatory/Travis Rector, University of Alaska Anchorage; SSRO/PROMPT/CTIO; T.A. Rector (University of Alaska Anchorage) and H. Schweiker (WIYN and NOAO/AURA/NSF)

4. Project Overview How does the galactic ecosystem change with SFR?
How does SF influence the galactic environment?
Reveal heating and cooling processes within a galaxy
What is the anatomy of a galaxy?
We can depict physical conditions inside a galaxy.
Green is molecular gas
Purple starbursts
Yellow is outflow
Stars are star forming regions Anatomy of a galaxy
Meier and Turner 2005

5. NGC 253 in detail Distance= 3.5 Mpc Vsys=235 km s-1
Barred spiral galaxy Class: SABc
Nucleated star burst ~3M yr-1
Total SFR ~5M yr-1
Molecular outflow rate ~9M yr-1 (Bolatto et al )
M molecular mass
Spitzer MIPS 24micron tracing the warm dust. .75 arcsec resolution

6. ALMA Molecular outflow Bolatto et al. 2013 
Dense gas, shock tracers, and RRL, Meier et al 
Diverse chemistry and structure traced by ALMA lines

7. Observations K and Ka band, D or C configurations
Ammonia (1,1) to (5,5) transitions 23-25GHz
Water(6-5) 22.3GHz
Methanol(4-3) 36.2GHz
Primary beam: ≈2 arcmin
Resolution: ≈6x4 arcsec
RMS: ≈ 0.6 mJy/chan
3.5 km/s /channel
WIDAR Correlator
Ammonia inversion unique to EVLA
Alma mostly thermal rotational transitions
EVLA masers

8. Spectra

9. 26-37 GHz Ka Band

10. Molecular Tracers CO (Carbon Monoxide): 115.271 GHz
Molecular Gas Tracer
NH3 (Ammonia): – GHz
Temperature and Dense Gas tracer.
H2O (Water): GHz,
Traces Shocks, collisionally excited maser. YSO, AGB stars, and AGN tori.
CH3OH (Methanol): GHz,
Class I maser, collisionally excited, shock tracer.
Focus on

11. Ammonia Thermometry
Rotation temperatures are derived from pairs of NH3 inversion lines
Kinetic temperatures can be estimated from LVG models
Peak Flux map of NH3 (3,3)
C1 = Continuum peak

12. NH3 & CO
NH3 follows CO gas fairly well

13. Temperature Structure
L3 slightly absorbed
3,3 bump
C1 derived from absorption spectrum

14. Temperature Structure
Rotation Temperatures
Trot(1,2): 36 ± 2 K
Trot(2,4): 84 ± 5 K
Trot(4,5): ± 15 K
Looks like there are 3 temperatures from fitting line pairs.
But….

15. Temperature Structure
LVG Extrapolation To Tkin
LVG predicts T_rot fro a given Tkin.
LVG extrapolation to Tkin predicts a “bend” in Boltzmann plots (Ott et al. 2011)

16. Temperature Structure
Uniform Two Temperature Model
Tkin(1,2): 57 ± 5 K
Tkin(2,4): ± 8 K
Tkin(4,5): ± 16 K
Two uniform temperatures 130K and 57K
Within 1 sigma errors we fit two temperatures across all of NGC253

17. Ammonia Masers NH3 masers span the centermost 250pc
Bump in 3,3 line about the center
Absorption in all lines but 3,3
NH3 masers span the centermost 250pc

18. Water masers
3 locations with water masers

19. Water Spectra LW1: 0.66 L LW2: >0.06 L LW3: 0.02 L
All detections are >3sigma
Luminosities are many orders of magnitude greater than Milky way at W1 Others are consistant with milkyway masers

20. Water masers (W1)
Super resolved cube dramatizes the extended emission 100pc along the minor axis
Brunthaler et al reveal starburst nature with VLBA
Velocities are consistent with models of outflow by Strickland et al and Westmoquette et al
Predicted outflow velocities are of order 10^2 km/s VLBA observations show starburst nature not AGN brunthaler 2009

21. 36 GHz Methanol
5 regions with masers

22. Methanol Spectra
5 distinct velocity components

23. Superbubbles
CO (Bolatto et al. 2013), Superbubbles (Sakamoto et al 2016)

24. Masers and the Outflow Strickland et al. 2011
Putting this all together, we ask how do these masers relate to the outflow?
Strickland et al. 2011

25. Conclusions Uniform two temperature distribution 130K and 57K
Several new water maser Candidates
Water maser extension seemingly along the outflow. Velocities match outflow cone models.
New methanol masers possibly associated with shocks in super bubbles.
No Temperature enhancement associated with super bubbles

26. Future Projects
Apply the same analysis to the other three galaxies in the sample
Look for relationships with star formation rates
Relationships with other structures in galaxies
Resolved studies of Ammonia, Methanol, and Water Masers

27. Questions