Search Publications
A massive black hole at the centre of the quiescent galaxy M32
van der Marel, Roeland P.; Rix, Hans-Walter; de Zeeuw, P. Tim +1 more
Massive black holes are thought to reside at the centres of many galaxies1,2, where they power quasars and active galactic nuclei. But most galaxies are quiescent, indicating that any central massive black hole present will be starved of fuel and therefore detectable only through its gravitational influence on the motions of the surroun…
A starburst origin of the OH-megamaser emission from the galaxy Arp220
Sturm, E.; Barlow, M. J.; Stacey, G. J. +3 more
Ultraluminous infrared galaxies have been known for more than a decade, but the source of their very large far-infrared luminosities remains controversial. It may reflect a quasar-like active nucleus surrounded by a torus of dense gas and dust, the latter absorbing the energetic photons from the nuclear region and re-emitting at infrared wavelengt…
Cassini mission blasts off for Saturn
Reichhardt, Tony
Star-forming galaxies at very high redshifts
Lanzetta, Kenneth M.; Yahil, Amos; Fernández-Soto, Alberto
Analysis of the deepest available images of the sky, obtained by the Hubble Space Telescope, reveals a large number of candidate high-redshift galaxies. A catalogue of 1,683 objects is presented, with estimated redshifts ranging from z = 0 to z > 6. The high-redshift objects are interpreted as regions of star formation associated with the proge…
Sub-galactic clumps at a redshift of 2.39 and implications for galaxy formation
Keel, W. C.; Odewahn, S. C.; Windhorst, R. A. +1 more
A large number of very faint, compact objects have been found at a redshift of 2.39 in optical images of the distant Universe. The objects appear to be star-forming spheroids smaller than the bulge of a spiral galaxy; they are much smaller and fainter than typical galaxies seen today. These objects may be part of a reservoir from which many of tod…
Abundance of 3He in the local interstellar cloud
Gloeckler, George; Geiss, Johannes
THE primordial abundances of the light elements and their isotopes provide essential information regarding the nucleosynthetic processes that occurred in the Big Bang1,2. At present the best estimates of the baryon/photon ratio of the Universe, a fundamental cosmological parameter, are extrapolations to primordial times of light-element…
Rapid energy dissipation and variability of the lo-Jupiter electrodynamic circuit
Prangé, Renée; Rego, Daniel; Ip, Wing +3 more
THE electrodynamic interaction between Jupiter and the closest of its large moons, Io, is unique in the Solar system. Io's volcanoes eject a considerable amount of material into the inner jovian system (>1 tonne per second), much of it in the form of ions1; the motion of Io through Jupiter's powerful magnetic field in turn generates …
The boron isotope ratio in the interstellar medium
Federman, S. R.; Lambert, David L.; Cardelli, Jason A. +1 more
OBSERVATIONS of the abundances of elements provide insight into their production and distribution. The production of light elements (in particular, lithium, beryllium and boron) is dominated by spallation reactions1, in which cosmic rays break apart more massive nuclei. Models2,3 suggest that the 11B/10B…
Cool gaze at heartless galaxies
Gilmore, Gerry
Near-coeval formation of the Galactic bulge and halo inferred from globular cluster ages
Gilmozzi, Roberto; Rich, R. Michael; Renzini, Alvio +4 more
THE morphology of our Galaxy is characterized by a disk of stars moving on circular orbits, surrounding a central spheroidal body of stars on high-velocity, randomly oriented orbits. The spheroid is further differentiated into an inner bulge and an outer halo; the bulge stars are rich in elements heavier than helium ('metals'), whereas the halo st…