THE IMPACT OF INTERACTIONS, BARS, BULGES, AND ACTIVE GALACTIC NUCLEI ON STAR FORMATION EFFICIENCY IN LOCAL MASSIVE GALAXIES

By A. Saintonge, L. Tacconi, S. Fabello, Jing Wang, B. Catinella, R. Genzel, J. Graciá-Carpio, C. Kramer, S. M. Moran, T. Heckman and 3 more. 2012

189 citations recorded by the source corpus.

Using atomic and molecular gas observations from the GASS and COLD GASS surveys and complementary optical/UV data from the Sloan Digital Sky Survey and the Galaxy Evolution Explorer, we investigate the nature of the variations in the molecular gas depletion time observed across the local massive galaxy population. The large and unbiased COLD GASS sample allows us for the first time to statistically assess the relative importance of galaxy interactions, bar instabilities, morphologies, and the presence of active galactic nuclei (AGNs) in regulating star formation efficiency. We find that both the H2 mass fraction and depletion time vary as a function of the distance of a galaxy from the main sequence traced by star-forming galaxies in the SFR–M* plane. The longest gas depletion times are found in below-main-sequence bulge-dominated galaxies (μ* >5 × 108 M☉ kpc−2, C > 2.6) that are either gas-poor (/M* <1.5%) or else on average less efficient by a factor of ∼2 than disk-dominated galaxies at converting into stars any cold gas they may have. We find no link between the presence of AGNs and these long depletion times. In the regime where galaxies are disk-dominated and gas-rich, the galaxies undergoing mergers or showing signs of morphological disruptions have the shortest molecular gas depletion times, while those hosting strong stellar bars have only marginally higher global star formation efficiencies as compared to matched control samples. Our interpretation is that the molecular gas depletion time variations are caused by changes in the ratio between the gas mass traced by the CO(1–0) observations and the gas mass in high-density star-forming cores (as traced by observations of, e.g., HCN(1–0)). While interactions, mergers, and bar instabilities can locally increase pressure and raise the ratio of efficiently star-forming gas to CO-detected gas (therefore lowering the CO-based depletion time), massive bulges may prevent the formation of dense clumps by stabilizing gas disks against fragmentation, therefore producing the long depletion times. Building a sample representative of the local galaxy population with M* >1010 M☉, we derive a global Kennicutt–Schmidt star formation relation of slope 1.18 ± 0.24 and observe structure within the scatter around this relation, with galaxies having low (high) stellar mass surface densities lying systematically above (below) the mean relation, suggesting that is not the only parameter driving the global star formation ability of a galaxy.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/cc72d242d2b2e8c5526c455aa5cc341e940f28f7

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. R. Somerville
4. M. Cappellari
5. R. Dav'e
6. A. Dekel
7. T. Naab
8. C. Conroy

In Instrumentation

1. M. Cappellari
2. P. Hopkins
3. L. Hernquist
4. A. Dekel
5. R. Dav'e
6. P. V. van Dokkum
7. T. Naab
8. R. Somerville

Citations in the corpus

• EXTENDING THE NEARBY GALAXY HERITAGE WITH WISE: FIRST RESULTS FROM THE WISE ENHANCED RESOLUTION GALAXY ATLAS (2012, methodology): “…et al. (2011), who compared the sSFR of star-forming, intermediate and bulge-dominated AGN-type galaxies, as well as the GASS/COLDGASS analysis (Saintonge et al., 2011; 2012) that explored the relationship between the atomic and molecular gas components and the star formation histories using…”
• The evolution of the dust and gas content in galaxies (2013, result): “Unless indicative of a larger fraction of atomic gas in starbursts, this result is in contrast with what suggested by previous studies, mostly based on CO emission (e.g., Daddi et al. 2010; Genzel et al. 2010; Saintonge et al. 2012; Magdis et al. 2012; Sargent et al. 2013).”
• Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, background): “…et al. 2006; Croton et al. 2006; Hopkins et al. 2006), as may the stabilizing effect of the bulge itself (Martig et al. 2009; Ceverino et al. 2010), which may contribute to the observed decrease of the star formation efficiency in ETGs (Saintonge et al. 2012; Martig et al. 2013; Davis et al. 2014).”
• VALIDATION OF THE EQUILIBRIUM MODEL FOR GALAXY EVOLUTION TO z ∼ 3 THROUGH MOLECULAR GAS AND DUST OBSERVATIONS OF LENSED STAR-FORMING GALAXIES (2013, background): “…relation is near-linear (e.g. Leroy et al. 2008; Blanc et al. 2009; Genzel et al. 2010; Daddi et al. 2010b; Bigiel et al. 2011; Rahman et al. 2012; Saintonge et al. 2012; Shetty et al. 2013; Feldmann 2013), the problem is further simplified and αCO can be estimated as: αCO,KS = SFR tdep(H2) L′CO…”
• xCOLD GASS: The Complete IRAM 30 m Legacy Survey of Molecular Gas for Galaxy Evolution Studies (2017, methodology): “Depletion time scaling relations In previous studies, we have reported systematic variations of the molecular gas depletion time, tdep(H2)=MH2/SFR, across the galaxy populations (Saintonge et al. 2011b, 2012, 2016; Genzel et al. 2015; Tacconi et al. 2017).”
• BULGE GROWTH AND QUENCHING SINCE z = 2.5 IN CANDELS/3D-HST (2014, background): “In the local universe, star formation efficiencies of bulge-dominated systems are reduced by factors of ∼ 2 − 3 compared to disk-dominated galaxies (Saintonge et al. 2012; Martig et al. 2013).”
• Evolution of the atomic and molecular gas content of galaxies (2013, background): “It is possible that a process not included in our model, such as AGN feedback, could destroy or expel H2 in massive galaxies (Saintonge et al. 2012) and possibly lower the number of H2 massive galaxies.”
• The evolution of the dust temperatures of galaxies in the SFR–M∗ plane up to z ~ 2 (2013, methodology): “Indeed, MS galaxies with their low SFR surface densities and star-formation efficiencies (SFE, i.e., SFR/Mgas; Saintonge et al. 2012) should have relatively low dust temperatures, while offMS galaxies with their high SFR surface densities and SFEs should have hotter dust temperatures.”
• COMBINED CO AND DUST SCALING RELATIONS OF DEPLETION TIME AND MOLECULAR GAS FRACTIONS WITH COSMIC TIME, SPECIFIC STAR-FORMATION RATE, AND STELLAR MASS (2014, methodology): “…in specific star formation rate at constant z and M* are due to a combination of variations in gas fraction and depletion time scale throughout the redshift range probed, in agreement with the z~0 COLDGASS results of Saintonge et al. (2012), Magdis et al. (2012b) and Huang & Kauffmann (2014).”
• Wet Disc Contraction to Galactic Blue Nuggets and Quenching to Red Nuggets (2013, background): “There is observational indication for such an effect (Saintonge et al. 2012; Crocker et al. 2012; Fang et al. 2013; Martig et al. 2013), and recent evidence in spectroscopically observed z ∼ 2 galaxies (Genzel et al. 2013).”
• Molecular hydrogen abundances of galaxies in the EAGLE simulations (2015, methodology): “8 that there is a tendency for τH2 to increase with increasing μ (Saintonge et al. 2012; Martig et al. 2013; Davis et al. 2014).”
• PHIBSS: Unified Scaling Relations of Gas Depletion Time and Molecular Gas Fractions (2017, background): “…qualitative agreement that tdepl decreases as one steps upward in sSFR perpendicular to the MS line at a given z and M*, as long as one considers a large enough range in δMS (Saintonge et al. 2011b, 2012, Leroy et al. 2013, Tacconi et al., 2013, Huang & Kauffmann 2014, Sargent et al. 2014, G15).”
• PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ∼ 1–3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES (2012, background): “In addition galaxies above the main-sequence also have smaller depletion time scales (Kennicutt & Evans 2012, Saintonge et al. 2012).”
• MOLECULAR GAS AND STAR FORMATION IN NEARBY DISK GALAXIES (2013, methodology): “Where we do overlap Saintonge et al. (2012), the agreement between the samples appears very good after our adjustment for different approaches to SFR estimation (§2).”
• The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, methodology): “…global molecular content of AGN hosts using the mm-wave J=1-0 CO emission-line show only small (Heckman et al. 1989) or no (Maiolino et al. 1997, Saintonge et al. 2012) differences in the molecular content of AGN hosts compared to normal galaxies (in terms of CO luminosity normalized by galaxy…”
• EVIDENCE FOR WIDE-SPREAD ACTIVE GALACTIC NUCLEUS-DRIVEN OUTFLOWS IN THE MOST MASSIVE z ∼ 1–2 STAR-FORMING GALAXIES (2014, background): “Tacconi et al. (2013), Magdis et al. (2012), and Saintonge et al. (2012) have presented evidence from molecular and dust observations that near the main-sequence sSFR correlates most strongly with galaxy baryonic gas fraction and star formation efficiency (the inverse of the gas depletion…”
• Molecular and atomic gas along and across the main sequence of star-forming galaxies (2016, background): “Rather, star formation efficiency varies smoothly as a function of SSFR (Saintonge et al. 2011b, 2012; Huang & Kauffmann 2014; Genzel et al. 2015).”
• The ATLAS3D Project – XXVIII. Dynamically driven star formation suppression in early-type galaxies (2014, background): “This average fraction appearsto decrease with increasing galaxy bulge fraction (Cappellari et al. 2013a, hereafter Paper XX; see also Saintonge et al. 2012).”
• REGULARITY UNDERLYING COMPLEXITY: A REDSHIFT-INDEPENDENT DESCRIPTION OF THE CONTINUOUS VARIATION OF GALAXY-SCALE MOLECULAR GAS PROPERTIES IN THE MASS-STAR FORMATION RATE PLANE (2013, unknown): “Saintonge et al. (2012) were able to sample molecular gas mass fraction variations over a larger range in sSFR which extends to significantly below the star forming MS and also slightly into the SB regime.”