scholarly journals CO Multi-line Imaging of Nearby Galaxies (COMING). I. Physical properties of molecular gas in the barred spiral galaxy NGC 2903

2016 ◽  
Vol 68 (5) ◽  
pp. 89 ◽  
Author(s):  
Kazuyuki Muraoka ◽  
Kazuo Sorai ◽  
Nario Kuno ◽  
Naomasa Nakai ◽  
Hiroyuki Nakanishi ◽  
...  
Keyword(s):  
Physical Properties ◽  
Spiral Galaxy ◽  
Molecular Gas ◽  
Nearby Galaxies ◽  
Barred Spiral Galaxy ◽  
Line Imaging

scholarly journals CO Multi-line Imaging of Nearby Galaxies (COMING). III. Dynamical effect on molecular gas density and star formation in the barred spiral galaxy NGC 4303

2019 ◽  
Vol 71 (Supplement_1) ◽  
Author(s):  
Yoshiyuki Yajima ◽  
Kazuo Sorai ◽  
Nario Kuno ◽  
Kazuyuki Muraoka ◽  
Yusuke Miyamoto ◽  
...  
Keyword(s):  
Star Formation ◽  
Spiral Galaxy ◽  
Galactic Disk ◽  
Molecular Gas ◽  
Kinetic Temperature ◽  
Spiral Arms ◽  
Nearby Galaxies ◽  
Barred Spiral Galaxy ◽  
Barred Spiral Galaxies ◽  
Line Imaging

AbstractWe present the results of $^{12}\textrm{C}$$\textrm{O}$(J = 1–0) and $^{13}\textrm{C}$$\textrm{O}$(J = 1–0) simultaneous mappings toward the nearby barred spiral galaxy NGC 4303 as part of the CO Multi-line Imaging of Nearby Galaxies (COMING) project. Barred spiral galaxies often show lower star-formation efficiency (SFE) in their bar region compared to the spiral arms. In this paper, we examine the relation between the SFEs and the volume densities of molecular gas n(H2) in the eight different regions within the galactic disk with $\textrm{C}$$\textrm{O}$ data combined with archival far-ultraviolet and 24 μm data. We confirmed that SFE in the bar region is lower by 39% than that in the spiral arms. Moreover, velocity-alignment stacking analysis was performed for the spectra in the individual regions. Integrated intensity ratios of $^{12}\textrm{C}$$\textrm{O}$ to $^{13}\textrm{C}$$\textrm{O}$ (R12/13) ranging from 10 to 17 were the results of this stacking. Fixing a kinetic temperature of molecular gas, $n(\rm {H_2})$ was derived from R12/13 via non-local thermodynamic equilibrium (non-LTE) analysis. The density n(H2) in the bar is lower by 31%–37% than that in the arms and there is a rather tight positive correlation between SFEs and n(H2), with a correlation coefficient of ∼0.8. Furthermore, we found a dependence of $n(\rm {H}_2)$ on the velocity dispersion of inter-molecular clouds (ΔV/sin i). Specifically, n(H2) increases as ΔV/sin i increases when ΔV/sin i < 100 km s−1. On the other hand, n(H2) decreases as ΔV/sin i increases when ΔV/sin i > 100 km s−1. These relations indicate that the variations of SFE could be caused by the volume densities of molecular gas, and the volume densities could be governed by the dynamical influence such as cloud–cloud collisions, shear, and enhanced inner-cloud turbulence.

scholarly journals Physical properties and kinematics of the molecular gas near galaxy nuclei

1997 ◽  
Vol 178 ◽  
pp. 489-500
Author(s):  
L.J. Tacconi
Keyword(s):  
Physical Properties ◽  
Spatial Resolution ◽  
Chemical Processes ◽  
Molecular Gas ◽  
Submillimeter Wavelength ◽  
Nearby Galaxies ◽  
Physical And Chemical ◽  
Size Scales ◽  
Made In ◽  
Gas Properties

During the last decade there have been enormous steps forward in our understanding of the molecular gas properties of other galaxies, due to the huge increase in sensitivity and spatial resolution of instruments in the millimeter and submillimeter wavelength ranges. In particular, the emphasis has shifted from trying to detect CO in a variety of objects to studying the gas distributions and kinematics in a variety of species and transitions. For nearby galaxies, we are now able to study the physical and chemical processes occurring in the molecular gas over GMC size scales. Here I discuss a few examples of progress made in the study of galaxy nuclei.

Constraining Baryons in the M31 galactic halo by Planck data

2019 ◽  
Vol 28 (07) ◽  
pp. 1950088 ◽  
Author(s):  
Noraiz Tahir ◽  
Francesco De Paolis ◽  
Asghar Qadir ◽  
Achille Nucita
Keyword(s):  
Physical Properties ◽  
Molecular Clouds ◽  
Galactic Halo ◽  
Molecular Gas ◽  
Galactic Halos ◽  
Planck Data ◽  
Nearby Galaxies ◽  
Galaxy Halo ◽  
Difficult Subject

The rotation of galactic halos is a particularly difficult subject to be dealt with. It has been shown that CMB data toward nearby galaxies can be used to probe the galactic halo rotation and can be ascribed to cold molecular clouds populating the halos. We present some methods to study the physical properties and distribution of such molecular gas clouds in the M31 galaxy halo.

scholarly journals Dense Molecular Gas Associated with the Circumnuclear Star‐forming Ring in the Barred Spiral Galaxy NGC 6951

1999 ◽  
Vol 511 (1) ◽  
pp. 157-177 ◽  
Author(s):  
Kotaro Kohno ◽  
Ryohei Kawabe ◽  
Baltasar Vila‐Vilaro
Keyword(s):  
Spiral Galaxy ◽  
Molecular Gas ◽  
Star Forming ◽  
Barred Spiral Galaxy

Dust and Molecular Gas in the Barred Spiral Galaxy NGC 1530

1995 ◽  
Vol 449 ◽  
pp. 576 ◽  
Author(s):  
Michael W. Regan ◽  
Stuart N. Vogel ◽  
Peter J. Teuben
Keyword(s):  
Spiral Galaxy ◽  
Molecular Gas ◽  
Barred Spiral Galaxy

scholarly journals CO multi-line imaging of nearby galaxies (COMING). IV. Overview of the project

2019 ◽  
Author(s):  
Kazuo Sorai ◽  
Nario Kuno ◽  
Kazuyuki Muraoka ◽  
Yusuke Miyamoto ◽  
Hiroyuki Kaneko ◽  
...  
Keyword(s):  
Sample Selection ◽  
Far Infrared ◽  
Stellar Mass ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Radio Observatory ◽  
Star Forming ◽  
Barred Galaxies ◽  
Nearby Galaxies ◽  
Line Imaging

Abstract Observations of the molecular gas in galaxies are vital to understand the evolution and star-forming histories of galaxies. However, galaxies with molecular gas maps of their whole discs at sufficient resolution to distinguish galactic structures are severely lacking. Millimeter-wavelength studies at a high angular resolution across multiple lines and transitions are particularly needed, severely limiting our ability to infer the universal properties of molecular gas in galaxies. Hence, we conducted a legacy project with the 45 m telescope of the Nobeyama Radio Observatory, called the CO Multi-line Imaging of Nearby Galaxies (COMING), which simultaneously observed 147 galaxies with high far-infrared (FIR) flux in 12CO, 13CO, and C18O J = 1–0 lines. The total molecular gas mass was derived using the standard CO–to–H2 conversion factor and found to be positively correlated with the total stellar mass derived from the WISE 3.4 μm band data. The fraction of the total molecular gas mass to the total stellar mass in galaxies does not depend on their Hubble types nor the existence of a galactic bar, although when galaxies in individual morphological types are investigated separately, the fraction seems to decrease with the total stellar mass in early-type galaxies and vice versa in late-type galaxies. No differences in the distribution of the total molecular gas mass, stellar mass, or the total molecular gas to stellar mass ratio was observed between barred and non-barred galaxies, which is likely the result of our sample selection criteria, in that we prioritized observing FIR bright (and thus molecular gas-rich) galaxies.

scholarly journals Kinematics and dynamics of molecular gas in galactic centers

2013 ◽  
Vol 9 (S303) ◽  
pp. 159-167
Author(s):  
K. Sakamoto
Keyword(s):  
Milky Way ◽  
Galactic Center ◽  
Molecular Gas ◽  
Disk Galaxies ◽  
Galactic Centers ◽  
External Galaxies ◽  
Nearby Galaxies ◽  
Barred Spiral Galaxy ◽  
Different Characteristics ◽  
Molecular Rings

AbstractThe central molecular zone (CMZ) in the central half kpc of the Milky Way is a massive concentration of molecular gas in the center of a barred spiral galaxy. Current and past activities in the Galactic center include the formation of massive stars/clusters, AGN feeding, and feedback. At the same time, observations of molecular gas in external galaxies show that many disk galaxies have similar condensations of molecular gas in their central kpc or so. They also have CMZs, or nuclear molecular rings or concentrations in more common terms among extragalactic observers. The formation of the CMZs are often, but not always, related to stellar bars. The centers of nearby galaxies can provide valuable information on the general properties of galactic centers and CMZs through comparative studies of multiple galactic centers of different characteristics from various viewing angles. Linear resolutions achieved toward nearby extragalactic CMZs with modern radio interferometers are now comparable to those achieved toward the Galactic CMZ with small single-dish telescopes. I review and present work on the formation mechanism and properties of the CMZs in external galaxies with some comparisons with the CMZ of our Galaxy.

scholarly journals 3.26. Molecular gas in the nuclear region and the bar of NGC 253

1998 ◽  
Vol 184 ◽  
pp. 141-142
Author(s):  
K. Sorai ◽  
N. Nakai ◽  
N. Kuno ◽  
K. Nishiyama
Keyword(s):  
Radio Telescope ◽  
Inclination Angle ◽  
Spiral Galaxy ◽  
Early Stage ◽  
Emission Lines ◽  
Molecular Gas ◽  
Nuclear Region ◽  
Star Forming ◽  
Barred Spiral Galaxy

In order to study relationship between molecular gas and star-forming activities, we have made observations of the barred spiral galaxy NGC 253 in 12CO(J = 1–0), 13CO(J = 1–0), and HCN(J = 1–0) emission lines with the Nobeyama 45-m radio telescope. NGC 253 is located in a distance of 2.5 M pc(Mauersbergeretal.(1996)) and has an inclination angle of 78°.5 (Pence 1980). This galaxy has a starburst nuclear region and is suggested in an early stage of a starburst (Rieke, Lebofsky, & Walker (1988)).

scholarly journals A High-Resolution CO Mapping of the Nucleus of the Barred-Spiral Galaxy, M83

1994 ◽  
Vol 140 ◽  
pp. 341-342 ◽  
Author(s):  
Toshihiro Handa ◽  
Sumio Ishizuki ◽  
Ryohei Kawabe
Keyword(s):  
High Resolution ◽  
Spiral Galaxy ◽  
Central Region ◽  
Molecular Gas ◽  
Nuclear Region ◽  
Circular Rotation ◽  
Frequency Coverage ◽  
Barred Spiral Galaxy ◽  
Gas Response ◽  
Co Emission

M83 is the best sample to investigate gas response to bar potential because it is one of the nearest galaxy with a pronounced bar structure (distance=3.7 Mpc). Handa et al. (1990) observed it with the Nobeyama 45-m telescope in CO(J=1-0) and found concentration of the CO emission to the dust lanes along the bar and non-circular rotation. However we need better spatial resolution in order to investigate kinematics and distribution of molecular gas in the nuclear region. So we observe the central region of M83 using the Nobeyama Millimeter Array. The synthesized beamsize was 12″ × 6″ and frequency coverage was 325 km s-1.

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