Search Publications
Galaxies at redshifts 5 to 6 with systematically low dust content and high [C II] emission
Ilbert, O.; Yan, L.; Carollo, C. M. +11 more
The rest-frame ultraviolet properties of galaxies during the first three billion years of cosmic time (redshift z > 4) indicate a rapid evolution in the dust obscuration of such galaxies. This evolution implies a change in the average properties of the interstellar medium, but the measurements are systematically uncertain owing to untested assu…
A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
Sing, David K.; Wheatley, Peter J.; Désert, Jean-Michel +8 more
Exoplanets orbiting close to their parent stars may lose some fraction of their atmospheres because of the extreme irradiation. Atmospheric mass loss primarily affects low-mass exoplanets, leading to the suggestion that hot rocky planets might have begun as Neptune-like, but subsequently lost all of their atmospheres; however, no confident measure…
A dusty, normal galaxy in the epoch of reionization
Richard, Johan; Gallazzi, Anna; Christensen, Lise +3 more
Candidates for the modest galaxies that formed most of the stars in the early Universe, at redshifts z > 7, have been found in large numbers with extremely deep restframe-ultraviolet imaging. But it has proved difficult for existing spectrographs to characterize them using their ultraviolet light. The detailed properties of these galaxies could…
Relativistic boost as the cause of periodicity in a massive black-hole binary candidate
Haiman, Zoltán; Schiminovich, David; D'Orazio, Daniel J.
Because most large galaxies contain a central black hole, and galaxies often merge, black-hole binaries are expected to be common in galactic nuclei. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries, most recently in PG 1302-102, which has a short rest-frame optical period …
Warm-hot baryons comprise 5-10 per cent of filaments in the cosmic web
Richard, Johan; Massey, Richard; Kneib, Jean-Paul +8 more
Observations of the cosmic microwave background indicate that baryons account for 5 per cent of the Universe’s total energy content. In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two. Cosmological simulations indicate that the missing baryons have not condensed into virialized haloes, but res…
Fast-moving features in the debris disk around AU Microscopii
Henning, Thomas; Schneider, Glenn; Boccaletti, Anthony +36 more
In the 1980s, excess infrared emission was discovered around main-sequence stars; subsequent direct-imaging observations revealed orbiting disks of cold dust to be the source. These `debris disks' were thought to be by-products of planet formation because they often exhibited morphological and brightness asymmetries that may result from gravitatio…
Resonant interactions and chaotic rotation of Pluto's small moons
Hamilton, D. P.; Showalter, M. R.
Four small moons--Styx, Nix, Kerberos and Hydra--follow near-circular, near-equatorial orbits around the central `binary planet' comprising Pluto and its large moon, Charon. New observational details of the system have emerged following the discoveries of Kerberos and Styx. Here we report that Styx, Nix and Hydra are tied together by a three-body …
A kiloparsec-scale internal shock collision in the jet of a nearby radio galaxy
Anderson, Jay; van der Marel, Roeland P.; Sparks, William B. +7 more
Jets of highly energized plasma with relativistic velocities are associated with black holes ranging in mass from a few times that of the Sun to the billion-solar-mass black holes at the centres of galaxies. A popular but unconfirmed hypothesis to explain how the plasma is energized is the `internal shock model', in which the relativistic flow is …
An extremely high-altitude plume seen at Mars' morning terminator
Phillips, J.; Sánchez-Lavega, A.; Delcroix, M. +10 more
The Martian limb (that is, the observed `edge' of the planet) represents a unique window into the complex atmospheric phenomena occurring there. Clouds of ice crystals (CO2 ice or H2O ice) have been observed numerous times by spacecraft and ground-based telescopes, showing that clouds are typically layered and always confined…
Ubiquitous time variability of integrated stellar populations
van Dokkum, Pieter G.; Choi, Jieun; Conroy, Charlie
Long-period variable stars arise in the final stages of the asymptotic giant branch phase of stellar evolution. They have periods of up to about 1,000 days and amplitudes that can exceed a factor of three in the I-band flux. These stars pulsate predominantly in their fundamental mode, which is a function of mass and radius, and so the pulsation pe…