Search Publications
Hard-X-ray emission lines from the decay of 44Ti in the remnant of supernova 1987A
Tsygankov, S. S.; Lutovinov, A. A.; Grebenev, S. A. +1 more
It is assumed that the radioactive decay of 44Ti powers the infrared, optical and ultraviolet emission of supernova remnants after the complete decay of 56Co and 57Co (the isotopes that dominated the energy balance during the first three to four years after the explosion) until the beginning of active interaction o…
The age of the Milky Way inner halo
Kalirai, Jason S.
The Milky Way galaxy has several components, such as the bulge, disk and halo. Unravelling the assembly history of these stellar populations is often restricted because of difficulties in measuring accurate ages for low-mass, hydrogen-burning stars. Unlike these progenitors, white dwarf stars, the `cinders' of stellar evolution, are remarkably sim…
Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan
Vinatier, Sandrine; Nixon, Conor A.; Irwin, Patrick G. J. +6 more
Saturn's moon Titan has a nitrogen atmosphere comparable to Earth's, with a surface pressure of 1.4 bar. Numerical models reproduce the tropospheric conditions very well but have trouble explaining the observed middle-atmosphere temperatures, composition and winds. The top of the middle-atmosphere circulation has been thought to lie at an altitude…
High velocity dispersion in a rare grand-design spiral galaxy at redshift z = 2.18
Erb, Dawn K.; Shapley, Alice E.; Steidel, Charles C. +3 more
Although grand-design spiral galaxies are relatively common in the local Universe, only one has been spectroscopically confirmed to lie at redshift z > 2 (HDFX 28; z = 2.011); and it may prove to be a major merger that simply resembles a spiral in projection. The rarity of spirals has been explained as a result of disks being dynamically `hot' …
Rapid disappearance of a warm, dusty circumstellar disk
Zuckerman, B.; Murphy, Simon J.; Song, Inseok +3 more
Stars form with gaseous and dusty circumstellar envelopes, which rapidly settle into disks that eventually give rise to planetary systems. Understanding the process by which these disks evolve is paramount in developing an accurate theory of planet formation that can account for the variety of planetary systems discovered so far. The formation of …
Atomic model of the type III secretion system needle
Baker, David; Loquet, Antoine; Sgourakis, Nikolaos G. +8 more
Pathogenic bacteria using a type III secretion system (T3SS) to manipulate host cells cause many different infections including Shigella dysentery, typhoid fever, enterohaemorrhagic colitis and bubonic plague. An essential part of the T3SS is a hollow needle-like protein filament through which effector proteins are injected into eukaryotic host ce…
Observation of interstellar lithium in the low-metallicity Small Magellanic Cloud
Mathews, Grant J.; Lehner, Nicolas; Howk, J. Christopher +1 more
The primordial abundances of light elements produced in the standard theory of Big Bang nucleosynthesis (BBN) depend only on the cosmic ratio of baryons to photons, a quantity inferred from observations of the microwave background. The predicted primordial 7Li abundance is four times that measured in the atmospheres of Galactic halo sta…
Comet-like mineralogy of olivine crystals in an extrasolar proto-Kuiper belt
Waters, L. B. F. M.; Ivison, R. J.; Blommaert, J. A. D. L. +20 more
Some planetary systems harbour debris disks containing planetesimals such as asteroids and comets. Collisions between such bodies produce small dust particles, the spectral features of which reveal their composition and, hence, that of their parent bodies. A measurement of the composition of olivine crystals (Mg2-2xFe2xSiO
Possible tropical lakes on Titan from observations of dark terrain
Tomasko, Martin G.; Brown, Robert H.; Griffith, Caitlin A. +5 more
Titan has clouds, rain and lakes--like Earth--but composed of methane rather than water. Unlike Earth, most of the condensable methane (the equivalent of 5 m depth globally averaged) lies in the atmosphere. Liquid detected on the surface (about 2 m deep) has been found by radar images only poleward of 50° latitude, while dune fields pervade the tr…