A Comparative Study of Giant Molecular Clouds in M51, M33, and the Large Magellanic Cloud

Hughes, Annie; Meidt, Sharon E.; Colombo, D.; Schinnerer, E.; Pety, J.; Leroy, Adam K.; Dobbs, Clare; García‐Burillo, S.; Thompson, Todd A.; Dumas, G.; Schuster, K.; Krämer, C.

doi:10.1088/0004-637x/779/1/46

Cited by 197 publications

(346 citation statements)

References 91 publications

(188 reference statements)

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“…On the contrary, our result would indicate that the GMAs are in diverse dynamical states. In fact, a lack of correlation between these two variables has also been reported in recent extragalactic observations with ≤ 50 pc resolution for a variety of galaxies (e.g., LMC, M33, M51, M101, NGC 628, and NGC 6946; Hughes et al 2013;Colombo et al 2014;Rebolledo et al 2015).…”

Section: Virial Parametersupporting

confidence: 58%

“…Extragalactic observations provide a perfect perspective for galactic-scale environments that are difficult to obtain from the edge-on Galactic observations. These observations of nearby galaxies redefine our understanding of galactic-scale environments such as galactic structures (bars, spiral arms, inter-arm regions) (Hughes et al 2013;Colombo et al 2014;Pan et al 2015a), regions of shear arising from galaxy rotation (Koda et al 2009;Meidt et al 2013;Miyamoto et al 2014), and galaxy types (dwarf, early-, and latetype galaxies) (Leroy et al 2008;Hughes et al 2013;Thilliez et al 2014) on the regulation of cloud properties. The importance of galactic-scale environments is also supported by galaxy simulations (Fujimoto et al 2014a;Renaud et al 2015).…”

Section: Introductionmentioning

confidence: 77%

“…By subtracting a galaxy rotation model from the cloud radial velocities, Hughes et al (2013) have shown that these effects have small influence on σ c for structures < 500 pc in CPROPS, and this result is insensitive to galaxy types 5 . The typical difference between GMA with and without rotation subtraction is smaller than our velocity resolution of 5 km s −1 .…”

Section: Velocity Dispersion (σC) and Rc-σc Relationmentioning

confidence: 99%

“…Accordingly, Larson (1981) and Solomon et al (1987) proposed that the cloud properties of the Milky Way are decoupled from their environments, namely, cloud properties are universal. However, further studies have revealed that cloud properties can be affected by local environments and conditions such as the ambient pressure (Blitz & Rosolowsky 2004;Hughes et al 2013;Meidt 2016) and star formation and feedback (e.g., supernovae, radiation pressure, and ionization) in the cloud (McKee 1989;Wolfire et al hapan@asiaa.sinica.edu.tw 1995; Tasker 2011). In addition, Heyer et al (2001) have suggested that the cloud properties depend on larger, galactic-scale environments.…”

Section: Introductionmentioning

confidence: 99%

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Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Pan

Kuno

2017

ApJ

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We study the physical properties of giant molecular cloud associations (GMAs) in M100 (NGC 4321) using the ALMA Science Verification feathered (12-m+ACA) data in 12 CO (1-0). To examine the environmental dependence of GMA properties, GMAs are classified based on their locations in the various environments as circumnuclear ring (CNR), bar, spiral, and inter-arm GMAs. The CNR GMAs are massive and compact, while the inter-arm GMAs are diffuse with low surface density. GMA mass and size are strongly correlated, as suggested by Larson (1981). However, the diverse power-law index of the relation implies that the GMA properties are not uniform among the environments. The CNR and bar GMAs show higher velocity dispersion than those in other environments. We find little evidence for a correlation between GMA velocity dispersion and size, which indicates that the GMAs are in diverse dynamical states. Indeed, the virial parameter of GMAs spans nearly two orders of magnitude. Only the spiral GMAs are in general self-gravitating. Star formation activity of the GMAs decreases in order over the CNR, spiral, bar, and the inter-arm GMAs. The diverse GMA and star formation properties in different environments lead to variations in the Kennicutt-Schmidt relation. A combination of multiple mechanisms or gas phase change is necessary to explain the observed slopes. Comparisons of GMA properties acquired with the use of the 12-m-array observations with those from the feathered data are also presented. The results show that the missing flux and extended emission cannot be neglected for the study of environmental dependence.

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Section: Virial Parametersupporting

confidence: 58%

Section: Introductionmentioning

confidence: 77%

Section: Velocity Dispersion (σC) and Rc-σc Relationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Pan

Kuno

2017

ApJ

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“…Allen 1993; Crosthwaite et al 2002;Blasco-Herrera et al 2010;Meidt et al 2013;Hughes et al 2013;Schinnerer et al 2013;Colombo et al 2014). Recent HERSCHEL observations of M 51 and M 83 at 70, 160, 250, 350, and 500 µm have provided maps of the dust temperature, surface density, and even spectral emissivity index, β Foyle et al , 2013Cooper et al 2012), but with spatial coverage that is slightly more limited than those of the AzTEC 1.1 mm continuum maps presented here; the AzTEC images cover a few more kiloparsecs at the adopted distances given in Table 1.…”

Section: The Current Workmentioning

confidence: 99%

Continuum observations of M 51 and M 83 at 1.1 mm with AzTEC

Wall

Puerari

Tilanus

et al. 2016

Mon. Not. R. Astron. Soc.

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We observed the spiral galaxies M 51 and M 83 at 20" spatial resolution with the bolometer array AzTEC on the JCMT in the 1.1 mm continuum, recovering the extended emission out to galactocentric radii of more than 12 kpc in both galaxies. The 1.1 mm-continuum fluxes are 5.6±0.7 and 9.9±1.4 Jy, with associated gas masses estimated at 9.4 × 10 9 M and 7.2 × 10 9 M for M 51 and M 83, respectively. In the interarm regions of both galaxies the N(H 2 )/I(CO) (or X-factor) ratios exceed those in the arms by factors of ∼ 1.5-2. In the inner disks of both galaxies, the X-factor is about 1 × 10 20 cm −2 · (K · km · s −1 ) −1 . In the outer parts, the CO-dark molecular gas becomes more important.While the spiral density wave in M 51 appears to influence the interstellar medium and stars in a similar way, the bar potential in M 83 influences the interstellar medium and the stars differently. We confirm the result of Foyle et al. (2010) that the arms merely heighten the star formation rate and the gas surface density in the same proportion. Our maps reveal a threshold gas surface density for an SFR increase by two or more orders of magnitude. In both galaxy centers, the molecular gas depletion time is about 1 Gyr climbing to 10-20 Gyr at radii of 6-8 kpc. This is consistent with an inside-out depletion of the molecular gas in the disks of spiral galaxies.

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Physical Processes in the Interstellar Medium

Klessen

Glover

2015

Star Formation in Galaxy Evolution: Connecting Numerical Models to Reality

155

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Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understanding its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolution, the formation of stars, cosmic nucleosynthesis, the origin of large complex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the interstellar medium. However, despite its importance, its structure and evolution is still not fully understood. Observations reveal that the interstellar medium is highly turbulent, consists of different chemical phases, and is characterized by complex structure on all resolvable spatial and temporal scales. Our current numerical and theoretical models describe it as a strongly coupled system that is far from equilibrium and where the different components are intricately linked together by complex feedback loops. Describing the interstellar medium is truly a multi-scale and multi-physics problem. In these lecture notes we introduce the microphysics necessary to better understand the interstellar medium. We review the relations between large-scale and small-scale dynamics, we consider turbulence as one of the key drivers of galactic evolution, and we review the physical processes that lead to the formation of dense molecular clouds and that govern stellar birth in their interior.

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A Comparative Study of Giant Molecular Clouds in M51, M33, and the Large Magellanic Cloud

Cited by 197 publications

References 91 publications

Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Continuum observations of M 51 and M 83 at 1.1 mm with AzTEC

Physical Processes in the Interstellar Medium

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