A study of the remarkable galaxy system AM 546-324 (the core of Abell S0546)

We report first results of an investigation of the tidally disturbed galaxy system AM\,546-324, whose two principal galaxies 2MFGC 04711 and AM\,0546-324 (NED02) were previously classified as interacting doubles. This system was selected to study the interaction of ellipticals in a moderately dense environment. We provide spectral characteristics of the system and present an observational study of the interaction effects on the morphology, kinematics, and stellar population of these galaxies. The study is based on long-slit spectrophotometric data in the range of $\sim$ 4500-8000 $\AA$ obtained with the Gemini Multi-Object Spetrograph at Gemini South (GMOS-S). We have used the stellar population synthesis code STARLIGHT to investigate the star formation history of these galaxies. The Gemini/GMOS-S direct r-G0303 broad band pointing image was used to enhance and study fine morphological structures. The main absorption lines in the spectra were used to determine the radial velocity. Along the whole long-slit signal, the spectra of the Shadowy galaxy (discovered by us), 2MFGC 04711, and AM\,0546-324 (NED02) resemble that of an early-type galaxy. We estimated redshifts of z= 0.0696, z= 0.0693 and z= 0.0718, corresponding to heliocentric velocities of 20\,141 km s$^{-1}$, 20\,057 km s$^{-1}$, and 20\,754 km s$^{-1}$ for the Shadowy galaxy, 2MFGC 04711 and AM\,0546-324 (NED02), respectively. ..

Evidence for Multiple Mergers among Ultraluminous IR Galaxies (ULIRGs): Remnants of Compact Groups?

In a large sample of ULIRGs imaged with HST, we have identified a significant subsample that shows evidence for multiple mergers. The evidence is seen among two classes of ULIRGs: (1) those with multiple remnant nuclei in their core, sometimes accompanied by a complex system of tidal tails; and (2) those that are in fact dense groupings of interacting (soon-to-merge) galaxies. We conservatively estimate that, in the redshift range 0.05<z<0.20, at least 20 (out of 99) ULIRGs satisfy one or both of these criteria. We present several cases and discuss the possibility that the progenitors of ULIRGs may be the more classical weakly interacting compact groups of galaxies (Hickson 1997). An evolutionary progression is consistent with the results: from compact groups to pairs to ULIRGs to ellipticals. The last step follows the blowout of gas and dust from the ULIRG.Comment: 5 pages, including 1 color postscript figure. Published in the Astrophysical Journal Letters (1 Feb 2000). Replaced with final edited version, including corrected typos and additional references, plus the color figure has been improved and is only available her

Factors influencing immunisation coverage among children under five years of age in Khartoum State, Sudan

Background This article explores the hypothesis that predisposing and enabling factors of households influence the vaccination status of the children under the age of five in Khartoum State, Sudan. Method The study was a cross-sectional survey among a representative sample of 410 male and female children under five years of age from households with varying socio-economic status and mothers with varying levels of education, from both urban and rural localities in the state. Results The correct vaccination coverage rate for children was found to be high. Children in urban and rural areas differed substantially in their correct vaccination rates and their receipt of each vaccine separately. Walking or travelling time to the place of vaccination was found to be longer in rural areas when compared with urban areas. The vaccination rate increased with an increase in the age of the children and the education level of the mother. Children of older mothers were more likely to have had the correct vaccinations. The mothers\' knowledge of and attitudes to vaccination showed a strong relationship with the vaccination status of their children. When the coverage rate for each vaccine was taken separately, the economic level of the households significantly affected only the BCG vaccine coverage. Most vaccinations occurred in public outlet agencies. Conclusion The large differences found in vaccination coverage by place of residence and level of mother\'s education suggest that much greater efforts are required by the government if better rates of correct vaccination are to be achieved in rural areas. South African Family Practice Vol. 49 (8) 2007: pp. 1