1. STScI March 24, 2004 Ebb & Flow: Molecular Gas and Star Formation in Nearby Spirals Michele Thornley Bucknell University/STScI With grateful thanks to: M. Regan, D. Calzetti, M. Meyer, M. Mutchler, R. Kennicutt, S.Vogel, T. Wong, T. Helfer, K. Sheth, C. Spohn-Larkins, R. Magee + the BIMA SONG & SINGS collaborations To take away: Value of wide-field surveys Promise of CO studies with millimeter interferometers Promise of studying gas, dust and star formation with Spitzer

2. STScI March 24, 2004 CO as an H 2 tracer Open question: dependence of “X-factor” on metallicity, temperature, e.g. (an extremely abbreviated list…) Maloney & Black 1988 Wilson 1995; Arimoto et al. 1996; Israel 1997 Regan 2000 Dame, Hartman, & Thaddeus 2001 Wei, Neininger, Huttemeister & Klein 2001 Boselli et al. 2002 Rosolowsky et al. 2003 Bolatto et al. 2003, Walter et al. 2003 (NGC 3627, BIMA SONG)

3. STScI March 24, 2004 Molecular gas in the Milky Way Dame, Hartmann, & Thaddeus 2001

4. STScI March 24, 2004 Questions to ask: Interaction of molecular and atomic gas? Distribution & population of molecular clouds? Dependence of star formation on large-scale dynamics? Variation between galaxies?

5. STScI March 24, 2004 Transitions between molecular & atomic gas Crosthwaite & Turner (2001, 2002) CO HI IC 342M83 10’ 5’ Pressure dependent cloud formation: e.g., Elmegreen 1993, Elmegreen & Parravano 1994, Elmegreen 1995, Sofue et al. 1995, Honma et al. 1995, Hidaka & Sofue 2002

6. STScI March 24, 2004 Local Group spirals Dame et al 1993 (~1.7kpc resolution) M31 Guelin 2000, Neininger et al 2001 (90 pc resolution) Loinard et al 1999 (200 pc resolution)

7. STScI March 24, 2004 M31 Loinard et al 1999 Berman 2001, Berman & Loinard 2002 Kinematics as constraints on bulge & disk distributions:  fast rotating, triaxial bulge  thick H 2 disk (or warping)? z 0 ~200-500pc

8. STScI March 24, 2004 Zooming in on M31 clouds Neininger et al 1998, Neininger et al. 2001 (~3-4 pc resolution)

9. STScI March 24, 2004 Local Group spirals Engargiola et al. 2003 (50 pc resolution), Rosolowsky et al. 2003 (20 pc resolution) M33 See also: Fukui et al. 2001, 2003 (LMC w/ NANTEN)

10. STScI March 24, 2004 M33 Kinematics and distribution provide constraints on cloud formation:  cloud size, low angular momentum  correlations in velocity gradients for separations < 500 pc Engargiola et al. 2003, Rosolowsky et al. 2003 Galactic M33

11. STScI March 24, 2004 BIMA Survey of Nearby Galaxies (BIMA SONG) Regan et al. 2001, Helfer et al. 2003 (Das et al. 2003)

12. STScI March 24, 2004 BIMA SONG Selection criteria: V sys < 2000 km sec -1 B T < 11 Sa-Sd i -20 o,D 25 <70’) 93% of the sample detected Chosen 44 spirals include: 29 bars (SAB+SB) 20 emission-line (Seyfert, LINER) 19 grand-design spirals 17 HII nuclei Average distance 12 Mpc (H 0 =75 km s -1 Mpc -1 ) Map out to R~5 kpc ab b bc c cd d (Hubble type) 0 5 10 number Unbarred Barred

13. STScI March 24, 2004 2 4 6 8 10 Sab/SbSbc Sc/Scd Central excess No central excess (5) (2) (3) (8) (6) Number 12 15 3 6 9 SASAB/SB Central excess No central excess (5) (6) (14) (2) Number BIMA SONG Radial Profiles Regan et al. 2001 Thornley et al. 2004 (in prep.) (27 of 44 galaxies)

14. STScI March 24, 2004 Central concentrations Central surface densities higher in barred spirals Statistical support for bar- induced inflow: Sakamoto et al. 1999 Sheth et al. 2004 High  nuc correlated with large surface mass density Perhaps bar not necessary for centrally peaked gas Sofue et al.2003 (Thornley et al. 2004) Sakamoto et al. 1999

15. STScI March 24, 2004 H 2,HI, and the Schmidt law in SONG galaxies Wong & Blitz 2002 (from Elmegreen 1989)

16. STScI March 24, 2004 Star Formation & Bars Sheth et al. 2002 (CO) (H  )

17. STScI March 24, 2004 Measuring streaming motions (NGC 5055) BIMA SONG CO velocity residuals (Thornley et al., 2004) HI & H, (Thornley & Mundy 1997)

18. STScI March 24, 2004 The future of millimeter studies CARMA (~2005) Cedar Flat CARMA on Cedar Flat (simulated) ALMA (~2008/2012) Chajnantor

19. STScI March 24, 2004 Other tracers of gas and dust? (BIMA SONG) Dale & Helou 2002 IRAC MIPS IRS/MIPS

20. STScI March 24, 2004 Spitzer Infrared Nearby Galaxies Survey (SINGS) PI: R. Kennicutt 75 nearby galaxies (d<30 Mpc) Range of Hubble type, luminosity, IR/optical Comprehensive database: IRAC/MIPS broadband imaging (3.6-160  m) IRS/MIPS SED strips (14-100  m) IRS spectral maps (5-37  m) Nuclear & extranuclear Lots of ancillary data! (optical/NIR, UV, CO, HI,…) SINGS website: http://sings.stsci.edu

21. STScI March 24, 2004 SINGS sample & plan Kennicutt et al. 2003, PASP, 115, 928 IRAC MIPS MIPS SED IRS (low) IRS(S-high) IRS(L-high)

22. STScI March 24, 2004 IRAC MIPS NGC 7331 Regan et al. 2004

23. STScI March 24, 2004 The ring in NGC 7331 Regan et al. 2004 + ring * outside ring, total (Scaled)

24. STScI March 24, 2004 Comparing gas, dust, and star formation gas Star formation ? ?

25. STScI March 24, 2004 Spectroscopy with Spitzer Nucleus Short Low Long High J.D. Smith et al. 2004

26. STScI March 24, 2004 M81: Early Release http://www.spitzer.caltech.edu NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

27. STScI March 24, 2004 Summary High spatial and spectral resolution observations of molecular gas in galaxies are becoming increasingly common. We are now able to examine the relationship of gas, dust, stars, and galactic structure over a range of galaxy types. We can address a wide variety of questions in a quantitative way: Cloud formation (e.g., turbulence, HI  H 2 ) Star formation variations Large- and small-scale kinematics