Search Publications
Long γ-ray bursts and core-collapse supernovae have different environments
Pian, E.; Ferguson, H. C.; Gull, T. R. +30 more
When massive stars exhaust their fuel, they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even more brilliant relativistic explosion known as a long-duration γ-ray burst. One would then expect that these long γ-ray bursts and core-collapse super…
A novel explosive process is required for the γ-ray burst GRB 060614
Sharon, K.; Cenko, S. B.; Peterson, B. A. +23 more
Over the past decade, our physical understanding of γ-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (>~2s) GRBs are associated with the explosive deaths of massive stars (`collapsars', ref. 1), which produce accompanying supernovae; the short-duration (<…
Stabilization of the disk around βPictoris by extremely carbon-rich gas
Weinberger, Alycia J.; Roberge, Aki; Feldman, Paul D. +2 more
The edge-on disk surrounding the nearby young star βPictoris is the archetype of `debris disks', which are composed of dust and gas produced by collisions between-and evaporation of-planetesimals, analogues of Solar System comets and asteroids. These disks may provide insight into the formation and early evolution of terrestrial planets. Previous …
Discovery of two new satellites of Pluto
Stern, S. A.; Weaver, H. A.; Mutchler, M. J. +6 more
Pluto's first known satellite, Charon, was discovered in 1978. It has a diameter (~1,200km) about half that of Pluto, which makes it larger, relative to its primary, than any other moon in the Solar System. Previous searches for other satellites around Pluto have been unsuccessful, but they were not sensitive to objects <~150km in diameter and …
Transiting extrasolar planetary candidates in the Galactic bulge
Brown, Thomas M.; Casertano, Stefano; Livio, Mario +13 more
More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to reflex motions of their host stars, and more recently through transits of some planets across the faces of the host stars. The detection of planets with the shortest known periods, 1.2-2.5 days, has mainly result…
A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper belt
Stern, S. A.; Weaver, H. A.; Mutchler, M. J. +6 more
The two newly discovered satellites of Pluto (P1 and P2) have masses that are small compared to both Pluto and Charon-that is, between 5 × 10-4 and 1 × 10-5 of Pluto's mass, and between 5 × 10-3 and 1 × 10-4 of Charon's mass. This discovery, combined with the constraints on the absence of more distant sa…
Rapid evolution of the most luminous galaxies during the first 900million years
Illingworth, Garth D.; Bouwens, Rychard J.
The first 900 million years (Myr) to redshift z ~ 6 (the first seven per cent of the age of the Universe) remains largely unexplored for the formation of galaxies. Large samples of galaxies have been found at z ~ 6 (refs 1-4) but detections at earlier times are uncertain and unreliable. It is not at all clear how galaxies built up from the first s…
Suppression of dwarf galaxy formation by cosmic reionization
Loeb, Abraham; Wyithe, J. Stuart B.
A large number of faint galaxies, born less than a billion years after the Big Bang, have recently been discovered. Fluctuations in the distribution of these galaxies contributed to a scatter in the ionization fraction of cosmic hydrogen on scales of tens of megaparsecs, as observed along the lines of sight to the earliest known quasars. Theoretic…
High-redshift galaxy populations
Cowie, Lennox L.; Hu, Esther M.
We now see many galaxies as they were only 800 million years after the Big Bang, and that limit may soon be exceeded when wide-field infrared detectors are widely available. Multi-wavelength studies show that there was relatively little star formation at very early times and that star formation was at its maximum at about half the age of the Unive…