Constraining the Multi-Phase Gas Content of Galaxies in the Local Cosmic Web D. V. Stark (UNC), S. J. Kannappan (UNC), L. H. Wei (UMD), A. J. Baker (Rutgers), M. P. Haynes (Cornell), R. Giovanelli (Cornell), F. Heitsch (UNC), and the RESOLVE and ALFALFA Teams RESOLVE: A Comprehensive Mass Census Mass census of all galaxies with M b a ry o n i c >~ 1.5x10 9 M s u n in two subvolumes totaling ~53,000 Mpc 3 Dynamical masses from SOAR long-slit/image-slicer survey of ionized gas and stellar kinematics Cluster/Group masses from redshift campaign Stellar masses from SED+spectral fitting using public UV/opt/NIR surveys Gas masses from methods described here Key science includes: ➢ Multi-scale constraints on missing baryons ➢ Merger rates as a function of dynamical mass and gas mass ratio ➢ Relationship of disk regrowth and pure disk galaxies to large scale structure ➢ Origin of gas richness threshold at log M s t a rs ~ 9.7 (Kannappan et al 2009) Introduction The RESOLVE Survey is a census of gas, stars, and dark matter within a well defined volume of the local universe. Here, we describe how we will account for the gas mass within RESOLVE across various temperature regimes. We will use both direct observations (e.g. 21 cm fluxes) and scaling relations (e.g. photometric gas fractions) to measure HI and H 2 . We will also investigate the universe’s undetected baryonic mass, commonly known as the “Missing Baryons” and believed to be mainly warm-hot ionized gas. Combining kinematically derived total masses with measurements of observable mass, we will constrain the missing baryons both within galaxies and in their surrounding environments, providing the most detailed mass census yet achieved over a large volume. Atomic Hydrogen (HI) ALFALFA-RESOLVE partnership (data reduction underway) Starting point Minimum detectable HI mass < ~10 9 M s u n Further completion Blue dwarfs and galaxies outside ALFALFA footprint: Photometric gas fractions (See poster 470.18 by Eckert et al) Red galaxies: Robust ALFALFA upper limits Large scale structure: Can determine mass of ensemble of HI without direct detections via stacking spectra (Catinella et al 2010). Conclusions Our purpose is to make a full gas census within the RESOLVE survey Methods vary from direct observations (21 cm) to scaling relations (photometric gas fractions) Application of multiple methods allows more accurate determination of gas mass, while illuminating conditions where different gas phases are important Study of H 2 mass-photometry relations reveals a central starburst cycle Studies of ultra-blue galaxies suggest another gas mass component unseen in HI and CO observations For more information on RESOLVE, see posters 470.18 (Eckert et al) and 470.19 (Liu et al) References Bettoni, D., Galletta, G., Garcia-Burillo, S. 2003, A&A, 405, 5 Casasola, V., Bettoni, D., Galletta, G. 2004, A&A, 422, 941 Catinella et al., 2010, in press Garnett, D. 2002, ApJ, 581, 1019 Giovanelli, R., et al. 2005, AJ, 130, 2598 Jansen, R. A., Fabricant, D., Franx, M., Caldwell, N. 2000a, ApJS, 126, 331 Jansen, R. A., Franx, M., Fabricant, D., Caldwell, N. 2000b, ApJS, 126, 271 Kannappan, S. J., Guie, J. M., and Baker, A. J. 2009. AJ, 138, 579 Kannappan, S. J., Jansen, R. A., and Barton, E. J. 2004. AJ, 127, 1371 Kannappan, S. J. and Wei, L. H. 2008, AIP Conf. Proc., 1035, 163 Leroy, A., Bolatto, A. D., Simon, J. D., Blitz, L. 2005, ApJ, 625, 763 Matthews, L. D., Gao, Y., Uson, J. M., Combes, F. 2005, AJ, 129, 1849 Wei, L. H., Kannappan, S. J., Vogel, S. N., Baker, A. J. 2010, ApJ, 708, 841 Figure 1: Initial RESOLVE sample from Kannappan and Wei (2008). SDSS galaxies brighter than M r =-17.23, between cz=4500-7000 km/s, including galaxies with no SDSS redshift but with a redshift in HyperLeda. Figure 3: (Left) Relation between M s t ar s and ∆(B-R), where ∆(B-R) = B-R from the half-light radius to the 75% light radius minus B-R within the half-light radius. Residuals in M st a rs vs ∆(B- R) define ∆(B-R) m cor r (blue-centeredness), adapted from the definition in Kannappan, Jansen, and Barton (2004). (Right) H 2 /HI ratio versus ∆(B-R) m c o r r , showing the rising and falling H 2 fractions associated with a central starburst. Kannappan, Jansen, Barton (2004) find that blue- centeredness is correlated with small interactions that can drive the observed burst cycle. Figure 5: (Left) Ultra-blue galaxies (B-K < 2.5) show lower HI/M s t ars than expected based on the rest of the galaxy population (Data from Nearby Field Galaxy Survey Database). (Right) Ultra-blue galaxies also show discrepancies in baryonic mass. The addition of CO-derived H 2 masses suggest the missing element is not molecular gas, but is more likely warm- hot ionized gas (Data from Bettoni et al 2003, Casasola et al (2004), Leroy et al (2005), Matthews et al (2005), and Garnett (2002)). How do we account for the gas mass? Figure 2: The RESOLVE footprint. Shaded regions mark ALFALFA overlap (85%). (Upper Right) ALFALFA detections as a function of distance (courtesy of M. Haynes). RESOLVE lies between 65 and 100 Mpc. Figure 4: Multiple measures of H 2 /HI fraction: ∆(B-R) m c o r r (left), ∆(U-B) m c o r r (middle) which follows same definition as ∆(B-R) mc o r r except with U-B color, and the global Hα equivalent width integrated over the whole galaxy (right). Investigation of individual galaxies highlights reasons why certain parameters fail to correlate with H 2 mass. For example, NGC 2780 and IC 2520 contain widespread dust, causing photometric measures (e.g. ∆(B-R) mc o r r ) to fail but spectroscopic measures (e.g. Hα equivalent width) to succeed in predicting H 2 mass. NGC 5762 and NGC 7077 appear to be pre- and/or post-starburst galaxies, indicating why Hα does not correlate with their H 2 mass. NGC 2780 IC 2520 NGC 5762 NGC 7077 Spring Region Fall Region Distance = cz/70 [Mpc] 0 50 100 150 200 250 11 10 9 8 7 6 5 Unseen Phases (Missing Baryons) Compare baryonic to total mass on large & small scales Possible new way to detect ionized gas reservoirs: ➢ Blue galaxies show low baryon fractions and low HI/M s t a rs (despite gas richness) relative to expectations (Fig. 5) ➢ Not gas loss – estimated SN feedback energy << energy needed to produce extended gas halos this massive ➢ Not just a mass dependency on non-baryonic dark matter (low mass red galaxies follow expectations) ➢ Missing mass likely warm-hot ionized gas, or possibly low- metallicity cold molecular gas – undetected mass can be estimated via relations seen in Figure 5. Star formation signatures can also distinguish between unseen baryonic and non-baryonic dark matter in the large scale RESOLVE mass inventory Molecular Hydrogen (H 2 ) Aim to calibrate “cheap” methods to estimate H 2 masses, in order to bootstrap from more demanding direct measurements (e.g. 12 CO emission) A. Correlation between H 2 /HI ratio and color gradients, which suggests central starburst cycle (see Figure 3) B. Reversing standard star formation laws (e.g. Hα H → 2 ) Combination of H 2 indicators provides more reliable mass measurements and helps determine when H 2 mass is significant Preliminary results below draw on the Nearby Field Galaxy Survey database, including photometry and spectroscopy from Jansen et al (2000a,b), HI data from Wei et al. (2010), and new H 2 data from our IRAM program underway. L o g H I M a s s [ s o l a r ]