Search Publications
The binarity of the local white dwarf population
Gänsicke, B. T.; Toonen, S.; Hollands, M. +1 more
Context. As endpoints of stellar evolution, white dwarfs (WDs) are powerful tools to study the evolutionary history of the Galaxy. In particular, the multiplicity of WDs contains information regarding the formation and evolution of binary systems.
Aims: Can we understand the multiplicity of the local WD sample from a theoretical point of view…
The extragalactic background light revisited and the cosmic photon-photon opacity
Franceschini, Alberto; Rodighiero, Giulia
Context. In addition to its relevant astrophysical and cosmological significance, the extragalactic background light (EBL) is a fundamental source of opacity for cosmic high energy photons, as well as a limitation for the propagation of high-energy particles in the Universe.
Aims: We review our previously published determinations of the EBL p…
The impact of clustering and angular resolution on far-infrared and millimeter continuum observations
Daddi, Emanuele; Béthermin, Matthieu; Wu, Hao-Yi +7 more
Follow-up observations at high-angular resolution of bright submillimeter galaxies selected from deep extragalactic surveys have shown that the single-dish sources are comprised of a blend of several galaxies. Consequently, number counts derived from low- and high-angular-resolution observations are in tension. This demonstrates the importance of …
The Open Flux Problem
Liu, Y.; Arge, C. N.; Henney, C. J. +9 more
The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational c…
The VLA-COSMOS 3 GHz Large Project: Multiwavelength counterparts and the composition of the faint radio population
Bondi, M.; Berta, S.; Ilbert, O. +18 more
We study the composition of the faint radio population selected from the Karl G. Jansky Very Large Array Cosmic Evolution Survey (VLA-COSMOS) 3 GHz Large Project, which is a radio continuum survey performed at 10 cm wavelength. The survey covers a 2.6 square degree area with a mean rms of 2.3 µJy/beam, cataloging 10 830 sources above 5σ, and…
New constraints on Saturn's interior from Cassini astrometric data
Thuillot, William; Pascu, Dan; Guillot, Tristan +15 more
Using astrometric observations spanning more than a century and including a large set of Cassini data, we determine Saturn's tidal parameters through their current effects on the orbits of the eight main and four coorbital Moons. We have used the latter to make the first determination of Saturn's Love number from observations, k2=0.390 …
Xenon isotopes in 67P/Churyumov-Gerasimenko show that comets contributed to Earth's atmosphere
Wurz, P.; Altwegg, K.; Balsiger, H. +27 more
The origin of cometary matter and the potential contribution of comets to inner-planet atmospheres are long-standing problems. During a series of dedicated low-altitude orbits, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) on the Rosetta spacecraft analyzed the isotopes of xenon in the coma of comet 67P/Churyumov-Gerasimen…
The Stellar Initial Mass Function in Early-type Galaxies from Absorption Line Spectroscopy. III. Radial Gradients
van Dokkum, Pieter; Romanowsky, Aaron J.; Conroy, Charlie +2 more
There is good evidence that the centers of massive early-type galaxies have a bottom-heavy stellar initial mass function (IMF) compared to that of the Milky Way. Here we study the radial variation of the IMF within such galaxies, using a combination of high-quality Keck spectroscopy and a new suite of stellar population synthesis models that cover…
On the generation of solar spicules and Alfvénic waves
De Pontieu, B.; Martínez-Sykora, J.; Hansteen, V. H. +3 more
In the lower solar atmosphere, the chromosphere is permeated by jets known as spicules, in which plasma is propelled at speeds of 50 to 150 kilometers per second into the corona. The origin of the spicules is poorly understood, although they are expected to play a role in heating the million-degree corona and are associated with Alfvénic waves tha…
Powering prolonged hydrothermal activity inside Enceladus
Postberg, Frank; Sotin, Christophe; Čadek, Ondřej +4 more
Geophysical data from the Cassini spacecraft imply the presence of a global ocean underneath the ice shell of Enceladus1, only a few kilometres below the surface in the South Polar Terrain2-4. Chemical analyses indicate that the ocean is salty5 and is fed by ongoing hydrothermal activity6-8. In order to …