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 ◽  
...  
2009 ◽  
Vol 693 (2) ◽  
pp. 1736-1748 ◽  
Author(s):  
C. D. Wilson ◽  
B. E. Warren ◽  
F. P. Israel ◽  
S. Serjeant ◽  
G. Bendo ◽  
...  

2020 ◽  
Vol 634 ◽  
pp. A24 ◽  
Author(s):  
Nimisha Kumari ◽  
Mike J. Irwin ◽  
Bethan L. James

Context. The global Schmidt law of star formation provides a power-law relation between the surface densities of star-formation rate (SFR) and gas, and successfully explains plausible scenarios of galaxy formation and evolution. However, star formation being a multi-scale process, requires spatially-resolved analysis for a better understanding of the physics of star formation. Aims. It has been shown that the removal of a diffuse background from SFR tracers, such as Hα, far-ultraviolet (FUV), infrared, leads to an increase in the slope of the sub-galactic Schmidt relation. We reinvestigate the local Schmidt relations in nine nearby spiral galaxies taking into account the effect of inclusion and removal of diffuse background in SFR tracers as well as in the atomic gas. Methods. We used multiwavelength data obtained as part of the Spitzer Infrared Nearby Galaxies Survey, Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel, The H I Nearby Galaxy Survey, and HERA CO-Line Extragalactic Survey. Making use of a novel split of the overall light distribution as a function of spatial scale, we subtracted the diffuse background in the SFR tracers as well as the atomic gas. Using aperture photometry, we study the Schmidt relations on background subtracted and unsubtracted data at physical scales varying between 0.5–2 kpc. Results. The fraction of diffuse background varies from galaxy to galaxy and accounts to ∼34% in Hα, ∼43% in FUV, ∼37% in 24 μm, and ∼75% in H I on average. We find that the inclusion of diffuse background in SFR tracers leads to a linear molecular gas Schmidt relation and a bimodal total gas Schmidt relation. However, the removal of diffuse background in SFR tracers leads to a super-linear molecular gas Schmidt relation. A further removal of the diffuse background from atomic gas results in a slope ∼1.4 ± 0.1, which agrees with dynamical models of star formation accounting for flaring effects in the outer regions of galaxies.


2010 ◽  
Vol 714 (1) ◽  
pp. 571-588 ◽  
Author(s):  
B. E. Warren ◽  
C. D. Wilson ◽  
F. P. Israel ◽  
S. Serjeant ◽  
G. J. Bendo ◽  
...  

1998 ◽  
Vol 184 ◽  
pp. 235-236
Author(s):  
Tony Wong ◽  
Tamara Helfer ◽  
Leo Blitz

It is well known that the radial distributions of atomic and molecular gas differ markedly in spiral galaxies, including our own (e.g. Burton & Gordon 1978, Sofue et al. 1995). We have recently begun a program to obtain multifrequency observations of several nearby galaxies in order to determine whether H I is needed to replenish the H2 consumed by star formation and, if so, how this might be accomplished. Here we present initial results on the nearby RSab galaxy NGC 4736, known for its bright ring of H II regions and recently shown to have a central stellar bar (Möllenhoff et al. 1995). We have mapped the distribution of CO (1-0) emission within r=1′ (1.8 kpc at D=6.2 Mpc) with the BIMA interferometer at ~5″ resolution, and added data from the NRAO 12-m telescope to recover zero-spacing information.


1998 ◽  
Vol 184 ◽  
pp. 245-246 ◽  
Author(s):  
K. Nishiyama ◽  
N. Nakai

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.


2015 ◽  
Author(s):  
Rob J. Beswick ◽  
Elias Brinks ◽  
Miguel Perez-Torres ◽  
Anita Richards ◽  
Susanne Aalto ◽  
...  

Author(s):  
Angus Mok ◽  
Christine Wilson

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.


1994 ◽  
Vol 140 ◽  
pp. 353-354 ◽  
Author(s):  
T. Tosaki ◽  
R. Kawabe ◽  
Y. Taniguchi

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).


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