scholarly journals The Galactic Distribution of the Spiral Nebulae, with Special Reference to Galactic Longitude.: (Plates 4, 5, 6.)

1923 ◽  
Vol 83 (3) ◽  
pp. 147-154 ◽  
Author(s):  
J. H. Reynolds
Keyword(s):  
Special Reference ◽  
Galactic Longitude ◽  
Galactic Distribution

scholarly journals Constraints on the distribution of supernova remnants with Galactocentric radius

2015 ◽  
Vol 454 (2) ◽  
pp. 1517-1524 ◽  
Author(s):  
D A Green
Keyword(s):  
Cosmic Rays ◽  
Power Law ◽  
Supernova Remnants ◽  
Exponential Model ◽  
Galactic Centre ◽  
Selection Effects ◽  
The Galaxy ◽  
Best Fitting ◽  
Galactic Longitude ◽  
Galactic Distribution

Abstract Supernova remnants (SNRs) in the Galaxy are an important source of energy injection into the interstellar medium, and also of cosmic rays. Currently there are 294 known SNRs in the Galaxy, and their distribution with Galactocentric radius is of interest for various studies. Here I discuss some of the statistics of Galactic SNRs, including the observational selection effects that apply, and difficulties in obtaining distances for individual remnants from the ‘$\Sigma$–D’ relation. Comparison of the observed Galactic longitude distribution of a sample of bright Galactic SNRs – which are not strongly affected by selection effects – with those expected from models is used to constrain the Galactic distribution of SNRs. The best-fitting power-law/exponential model is more concentrated towards the Galactic Centre than the widely used distribution obtained by Case & Bhattacharya.

scholarly journals The Galactic Distribution of Wolf-Rayet Stars

1982 ◽  
Vol 99 ◽  
pp. 27-40 ◽  
Author(s):  
B. Hidayat ◽  
K. Supelli ◽  
K.A. van der Hucht
Keyword(s):  
Spiral Structure ◽  
Galactic Center ◽  
Narrow Band ◽  
Interstellar Extinction ◽  
Spiral Arms ◽  
Recent Compilation ◽  
Galactic Longitude ◽  
Galactic Distribution

On the basis of the most recent compilation of narrow-band photometry and absolute visual magnitudes of Wolf-Rayet stars, and adopting a normal interstellar extinction law in all directions, the galactic distribution of 132 of the 159 known galactic WR stars is presented and discussed.The spiral structure is found to be more clearly pronounced than in earlier studies. Furthermore we find an indication of two spiral arms at r=4 and 6 kpc. There appears to be an asymmetry of the z-distribution of single stars with respect to galactic longitude.The location of the WC8.5 and WC9 stars between 4.5 and 9 kpc from the galactic center is discussed in the context of Maeder's red supergiant to WR star scenario.

scholarly journals The Galactic distribution of SNRs

2013 ◽  
Vol 9 (S296) ◽  
pp. 188-196 ◽  
Author(s):  
D. A. Green
Keyword(s):  
Supernova Remnants ◽  
Selection Effects ◽  
Observational Selection ◽  
The Galaxy ◽  
Galactic Longitude ◽  
Galactic Distribution

AbstractIt is not straightforward to determine the distribution of supernova remnants (SNRs) in the Galaxy. The two main difficulties are that there are observational selection effects that mean that catalogues of SNRs are incomplete, and distances are not available for most remnants. Here I discuss the selection effects that apply to the latest catalogue of Galactic SNRs. I then compare the observed distribution of ‘bright’ SNRs in Galactic longitude with that expected from models in order to constrain the Galactic distribution of SNRs.

Variation of the amount of hydrogen along the galactic ridge

1967 ◽  
Vol 31 ◽  
pp. 171-172
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Surface Brightness ◽  
Milky Way ◽  
Neutral Hydrogen ◽  
Line Of Sight ◽  
Optical Surface ◽  
Hydrogen Density ◽  
Continuous Radiation ◽  
Galactic Longitude

The integralNHof neutral-hydrogen density along the line of sight is determined from the Kootwijk and Sydney surveys. The run ofNHwith galactic longitude agrees well with that of thermal continuous radiation and that of the optical surface brightness of the Milky Way.

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