Publications by authors named "Michael A Strauss"
The detection of starlight from the host galaxies of quasars during the reionization epoch (z > 6) has been elusive, even with deep Hubble Space Telescope observations. The current highest redshift quasar host detected, at z = 4.5, required the magnifying effect of a foreground lensing galaxy.
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- - 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.
Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures (that is, clusters of galaxies and even larger assemblies) predicts the existence of quasars gravitationally lensed by concentrations of dark matter so massive that the quasar images would be split by over 7 arcsec. Numerous searches for large-separation lensed quasars have, however, been unsuccessful.
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- Researchers trace molecular hydrogen using carbon monoxide (CO) emissions, with notable detections in quasars at redshifts greater than 2, including one at z = 4.69.
- A new study reports CO emission from quasar SDSS J114816.64 + 525150.3, located at z = 6.42, indicating that heavy-element enrichment in molecular gas can occur quickly in young galaxies from the early Universe.