ROSAT PSPC observations of nearby spiral galaxies – II. Statistical properties

We present a statistical analysis of the largest X-ray survey of nearby spiral galaxies in which diffuse emission has been separated from discrete source contributions. Regression and rank-order correlation analyses are used to compare X-ray properties, such as total, source and diffuse luminosities and diffuse emission temperature, with a variety of physical and multiwavelength properties, such as galaxy mass, type and activity, and optical and infrared luminosity.
The results are discussed in terms of the way in which hot gas and discrete X-ray sources scale with the mass and activity of galaxies, and with the star formation rate. We find that the X-ray properties of starburst galaxies are dependent primarily on their star-forming activity, whilst for more quiescent galaxies, galaxy mass is the more important parameter. One of the most intriguing results is the tight linear scaling between far-infrared and diffuse X-ray luminosity across the sample, even though the hot gas changes from a hydrostatic corona to a free wind across the activity range sampled here.     

First record of sea snake (Hydrophis elegans, Hydrophiinae) entrapped in marine debris

Entanglement in derelict fishing gear and other marine debris is a major threat to the survival of large marine wildlife like cetaceans, seabirds and sea turtles. However, no previous reports of entanglement or entrapment have been recorded in sea snakes (Hydrophiinae). We report here on a sea snake (Hydrophis elegans) found with a ceramic washer encircling its body captured from the north-east coast of Queensland, Australia. The ring had constricted the body and over time caused extensive damage to the underlying tissues. A post-mortem examination showed the snake was severely emaciated as the ring restricted the passage of food to the stomach and intestine. This is the first record of mortality due to marine debris entrapment in sea snakes.     

Exospheric solar wind charge exchange as seen by XMM‐Newton

We review a selection of recent papers describing solar wind charge exchange emission occurring in the Earth's exosphere as seen by the X‐ray observatory XMM‐Newton. We discuss the detection of this emission, the occurrence with respect to the solar cycle and solar activity, and various spectral signatures observed. We also describe a model developed to predict the X‐ray signal from exospheric charge exchange as would be detected by XMM‐Newton, given the upstream solar wind conditions obtained from in situ solar wind monitors (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

POSSIBLE IMPACT SPHERULES FROM NEAR THE BASE OF THE MIDDLE ORDOVICIAN IN NORTHERN ILLINOIS

Angular fragments of a greyish-white chert-like rock containing numerous sand-size spherules believed to be of impact origin have been found in northern Illinois. These fragments, many as large as a man's fist, are recognizable in the field by the presence in them of conspicuous rounded cavities which were probably bubbles. Most have been picked up as float in the bottoms of ravines, but it is clear that they come from near the base of the St. Peter sandstone and that they were already fragments when incorporated in this formation. The original mineralogy of the spherules is obscure because of wholesale replacement by microcrystalline quartz. But the shapes of some of the original minerals have been preserved as pseudomorphs. Judging from the arrangement of these pseudomorphs, and the distribution of opaque material in which they are imbedded, it appears that some spherules attained their present size as liquid droplets. Others apparently solidified as they grew. The original spherule deposit, which must have been at least 15 cm thick in some places, was evidently hot enough, and sufficiently plastic, to permit the formation of large bubbles. It is not clear how the original deposit was broken into fragments.     

THE BROWNELL AND NESS COUNTY (1894) L6 CHONDRITES: FURTHER SORTING-OUT OF NESS COUNTY METEORITES

Brownell is a new, moderately shocked, L6 chondrite from Ness County, Kansas that is petrologically distinct from the other L6 chondrites from Ness County. These latter meteorites, Wellmanville, Franklinville and Ness County (1894), are very similar in their olivine and low-Ca pyroxene compositional distributions, kamacite Co contents, modal abundances of metallic Fe, Ni and presence of martensitic metallic Fe, Ni (∼ 14 wt. % Ni). However, their silicates indicate that they have been shocked to different extents. We suggest that all three probably represent a single, heterogeneously-shocked, L6 fragmental breccia that fell over a large area, > 30 km in length.