Gamma-Ray Observations and the Large Scale Structure of the Galaxy

Author(s):  
J. A. Paul
1991 ◽  
Vol 148 ◽  
pp. 89-95
Author(s):  
S. J. Meatheringham

The Small and Large Magellanic Clouds (SMC, LMC) are of considerable interest from a kinematical viewpoint. The tidal interation of the Clouds with each other and with the Galaxy appears to have been quite significant in recent times (Murai & Fujimoto 1980). The SMC in particular appears to have been considerably disrupted by a recent close passage to the LMC (Mathewson & Ford 1984, Mathewson 1984, Mathewson et al. 1986). For the LMC Freeman et al. (1983) found that the young and old populations have significantly different rotation solutions.Planetary Nebulae (PN) form a population with age intermediate between the HI and young clusters and the old Population II clusters. A large number of PN are known in the MCs. Sanduleak et al. (1978) compiled a list of 102 in the LMC and 28 in the SMC. Since then other authors have increased the total number known to approximately 140 in the LMC and 50 in the SMC.


1979 ◽  
Vol 84 ◽  
pp. 125-130
Author(s):  
J. A. Paul

Within the last few years, γ-ray astronomy has shifted from the discovery phase to the exploratory phase, thanks to the SAS-2 and COS-B satellites. The strongest feature of the γ-ray sky is the overwhelming emission of the galactic disc; even the radiation observed away from the galactic plane appears to be predominantly galactic, on the basis of its latitude dependence (Fichtel et al., 1978). Nevertheless, extragalactic γ-ray astronomy is not hopeless: the γ-radiation of the nearby quasar 3C273 has been very recently detected (Swanenburg et al., 1978). A brief summary of the present status of the galactic γ-ray astronomy follows.


1985 ◽  
Vol 106 ◽  
pp. 203-204
Author(s):  
W.H. Mccutcheon ◽  
B. J. Robinson ◽  
R. N. Manchester ◽  
J. B. Whiteoak

The southern galactic-plane region, in the ranges 294° ≤ 1 ≤ 358°, −0°.075 ≤ b ≤ 0°.075, has been surveyed in the J = 1–0 line of 12CO with a sampling interval of 3′ arc. Observations were made with the 4-metre telescope at the CSIRO Division of Radiophysics in 1980 and 1981. Details of equipment and observing procedure are given in Robinson et al. (1982, 1983); see also McCutcheon et al. (1983).


2005 ◽  
Vol 216 ◽  
pp. 196-202
Author(s):  
Martin Zwaan ◽  
Martin Meyer ◽  
Rachel Webster ◽  
Lister Staveley-Smith

The HI Parkes All Sky Survey (HIPASS) offers a unique perspective on the galaxy population in the local universe. A catalogue of 4315 HI-selected galaxies has been extracted from the southern region of the survey (δ < +2°). This catalogue gives a clear view of the local large-scale structure and is used to study the two-point correlation function, the Tully-Fisher relation, and galaxy luminosity and mass functions. Some initial results are discussed here.


1978 ◽  
Vol 77 ◽  
pp. 33-48 ◽  
Author(s):  
P.C. van der Kruit

This review concerns the large-scale structure of radio continuum emission in spiral galaxies (“the smooth background”), by which we mean the distribution of radio surface brightness at scales larger than, say, 1 kpc. Accordingly the nuclear emission and structure due to spiral arms and HII regions will not be a major topic of discussion here. Already the first mappings of the galactic background suggested that there is indeed a distribution of radio continuum emission extending throughout the Galaxy. This conclusion has been reinforced by the earliest observations of M31 by showing that the general emission from this object extended over at least the whole optical image. More recently, van der Kruit (1973a, b, c) separated the radio emission from a sample of spiral galaxies observed at 1415 MHz with the Westerbork Synthesis Radio Telescope (WSRT) into a nuclear, spiral arm and “base disk” component, showing that the latter component usually contains most of the flux density. This latter component is largely non-thermal and extends over the whole optical image (see also van der Kruit and Allen, 1976). Clearly it is astrophysically interesting to discuss the large-scale structure of the radio continuum emission.


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