Publications by authors named "Dean C Hines"
Article Synopsis
- - The most distant known quasars, found at redshift z approximately 6, appear to be evolved objects that are surprisingly similar to lower-redshift quasars, despite the Universe being only about 7% of its current age at that time.
- - A recent study discovered a second quasar without emissions from hot dust, raising questions about whether this is a unique case or indicative of a broader trend at high redshift.
- - Findings suggest that these high-redshift quasars, like the two without hot-dust emission, are in an early stage of evolution, growing rapidly with their central black holes, and likely formed in dust-free environments, indicating they haven't had time to accumulate hot dust.
Two images of Cassiopeia A obtained at 24 micrometers with the Spitzer Space Telescope over a 1-year time interval show moving structures outside the shell of the supernova remnant to a distance of more than 20 arc minutes. Individual features exhibit apparent motions of 10 to 20 arc seconds per year, independently confirmed by near-infrared observations. The observed tangential velocities are at roughly the speed of light.
View Article and Find Full Text PDFA large amount (about three solar masses) of cold (18 K) dust in the prototypical type II supernova remnant Cassiopeia A was recently reported. It was concluded that dust production in type II supernovae can explain how the large quantities (approximately 10(8) solar masses) of dust observed in the most distant quasars could have been produced within only 700 million years after the Big Bang. Foreground clouds of interstellar material, however, complicate the interpretation of the earlier submillimetre observations of Cas A.
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