Molecular Gas in Spiral Galaxies

1996 ◽  
pp. 50-60 ◽  
Author(s):  
Ronald J. Allen
Keyword(s):  
Spiral Galaxies ◽  
Molecular Gas

scholarly journals 5.17. The NRO CO survey of nearby spiral galaxies

1998 ◽  
Vol 184 ◽  
pp. 245-246 ◽  
Author(s):  
K. Nishiyama ◽  
N. Nakai
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Spiral Galaxies ◽  
High Spatial Resolution ◽  
Molecular Gas ◽  
Characteristic Structure

Our survey observation is high spatial resolution (16″) by NRO observatory 45 m antenna and have many galaxies of sample. This high resolution observations (16″ = 1.6 kpc at 20 Mpc) could be to resolve the some characteristic structure, typical molecular gas disk, arm - interarm and optical bar.

scholarly journals The JCMT Nearby Galaxies Legacy Survey – XI. Environmental variations in the atomic and molecular gas radial profiles of nearby spiral galaxies

2017 ◽  
Vol 467 (4) ◽  
pp. 4282-4292 ◽  
Author(s):  
Angus Mok ◽  
C. D. Wilson ◽  
J. H. Knapen ◽  
J. R. Sánchez-Gallego ◽  
E. Brinks ◽  
...  
Keyword(s):  
Spiral Galaxies ◽  
Molecular Gas ◽  
Radial Profiles ◽  
Environmental Variations ◽  
Nearby Galaxies

scholarly journals Environmental Effects on the ISM and Star Formation Properties of Nearby Spiral Galaxies

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Angus Mok ◽  
Christine Wilson
Keyword(s):  
Star Formation ◽  
Environmental Effects ◽  
Spiral Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Molecular Gas ◽  
Turbulent Pressure ◽  
Cluster Environment ◽  
Gas Properties

AbstractWe studied molecular gas properties in a sample of 98 Hi - flux selected spiral galaxies within ~ 25 Mpc using the CO J = 3 − 2 line, observed with the JCMT, and subdivided into isolated, group, and Virgo subsamples. We find a larger mean H2 mass in the Virgo galaxies compared to group galaxies, despite their lower mean Hi mass. Combining our data with complementary Hα star formation rate measurements, Virgo galaxies have a longer molecular gas depletion times compared to group galaxies, perhaps due to heating processes in the cluster environment or differences in the turbulent pressure.

scholarly journals Molecular Superclouds in M51

1994 ◽  
Vol 140 ◽  
pp. 353-354 ◽  
Author(s):  
T. Tosaki ◽  
R. Kawabe ◽  
Y. Taniguchi
Keyword(s):  
High Resolution ◽  
Molecular Clouds ◽  
Spiral Galaxies ◽  
Molecular Gas ◽  
Giant Molecular Clouds

Recently, it has been shown that some of nearby spiral galaxies have very massive (107-8Mʘ) and large (several 100 pc - ~ 1 kpc) molecular gas clouds (M51: Rand & Kulkarni 1990; NGC1068: Planesas et al. 1991). Since these clouds are significantly more massive and larger than those of so-called Giant Molecular Clouds (GMCs) found in our Galaxy, they are called Molecular Super-clouds (Rand & Kulkarni 1990; hereafter MSCs). In order to study observational properties of MSCs, we present the results of high-resolution (4”) 12CO(J=1-0) mosaic mapping of central 2.’5 region of the Sbc galaxy M51 using the Nobeyama Millimeter Array (NMA). Our main results are summarized in the followings (Tosaki, Kawabe & Taniguchi 1992).

scholarly journals Head-on collisions: how to bring large quantities of gas out of inner disks

2004 ◽  
Vol 217 ◽  
pp. 420-421
Author(s):  
Jonathan Braine ◽  
U. Lisenfeld ◽  
P.-A. Duc
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Intergalactic Medium ◽  
Spiral Galaxies ◽  
Molecular Gas ◽  
Hii Region ◽  
Neutral Gas ◽  
Dense Cores ◽  
Clear Cases ◽  
Formation Efficiency

Head-on collisions of spiral galaxies can bring large quantities of gas out of spiral disks and into the intergalactic medium. Only two clear cases (UGC 12914/5 and UGC 813/6) of such collisions are known (Condon et al. 1993, 2002) and in both cases several 109 M⊙ of neutral gas is found in the bridge between the two galaxies which are now separating. About half of the gas is molecular. The gas, atomic or molecular, is brought out by collisions between clouds, which then acquire an intermediate velocity and end up between the galaxies. The bridges contain no old stars and in each case only one HII region despite the large masses of molecular gas, such that the star formation efficiency is very low in the bridges. The collisions occurred 20 – 50 million years ago, much greater than the collapse time for dense cores. We (Braine et al. 2003, 2004) show that collisions between molecular clouds, and not only between atomic gas clouds, bring gas into the bridges. It is not currently known whether the galaxies and bridges are bound or whether they will continue to separate, releasing several 109 M⊙ of neutral gas into the intergalactic medium.

scholarly journals 5.2. Molecular gas and nuclear outflows

1998 ◽  
Vol 184 ◽  
pp. 213-214
Author(s):  
Judith A. Irwin
Keyword(s):  
Spiral Galaxies ◽  
Molecular Gas ◽  
X Ray ◽  
Overwhelming Evidence ◽  
The Galaxy

There is now overwhelming evidence that spiral galaxies can experience nuclear outflows, from radio lobes perpendicular to the disks of edge-on galaxies (Hummel et al. 1983), to optical ionization cones (see list in Wilson and Tsvetanov 1994), to spectacular X-ray emission extending many kpc beyond the disk (e.g. Dahlem et al. 1996). These observations indicate that hot and/or energetic components of the ISM can escape away from the plane of the galaxy from their origin in the nuclear vicinity.

scholarly journals Environmental Effects: The Molecular Gas in Spiral Galaxies

1999 ◽  
Vol 186 ◽  
pp. 409-409
Author(s):  
D.F. de Mello ◽  
T. Wiklind ◽  
M. Maia
Keyword(s):  
Environmental Effects ◽  
Spiral Galaxies ◽  
Gas Content ◽  
Density Contrast ◽  
Molecular Gas ◽  
Low Density

We have started a survey of the molecular gas content of spiral galaxies in high and low density regions (HDS and CS), selected according to well-defined criteria (Maia et al. 1994, ApJS, 93, 425). The HDS sample is formed by galaxies that are in groups of three or more members. The groups are defined such that they have a density contrast δρ/ρ ≥ 500. This is equivalent to densities larger than 18 galaxies/Mpc3. The CS sample is made up of galaxies which are not members of any group and which are situated in a region with a density contrast δρ/ρ ≤ 0.01, i.e. less than 0.0004 galaxies/Mpc3.

scholarly journals Radial Transport of Molecular Gas to the Nuclei of Spiral Galaxies

2000 ◽  
pp. 132-135
Author(s):  
K. Sakamoto ◽  
S.K. Okumura ◽  
S. Ishizuki ◽  
N.Z. Scoville
Keyword(s):  
Spiral Galaxies ◽  
Molecular Gas ◽  
Radial Transport
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