Search Publications
Measuring the speed of cosmological gravitational waves
Raveri, Marco; Silvestri, Alessandra; Baccigalupi, Carlo +1 more
In general relativity gravitational waves propagate at the speed of light; however, in alternative theories of gravity that might not be the case. We investigate the effects of a modified speed of gravity, cT2, on the B modes of the cosmic microwave background (CMB) anisotropy in polarization. We find that a departure from th…
Measurements of the near-nucleus coma of comet 67P/Churyumov-Gerasimenko with the Alice far-ultraviolet spectrograph on Rosetta
Parker, Joel Wm.; Bertaux, Jean-Loup; Weaver, Harold A. +8 more
Aims. The Alice far-ultraviolet spectrograph onboard Rosetta is designed to observe emissions from various atomic and molecular species from within the coma of comet 67P/ Churyumov-Gerasimenko and to determine their spatial distribution and evolution with time and heliocentric distance. Methods. Following orbit insertion in August 2014, Alice made…
Evolution of the lower hybrid drift instability at reconnection jet front
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +3 more
We investigate current-driven modes developing at jet fronts during collisionless reconnection. Initial evolution of the reconnection is simulated using conventional 2-D setup starting from the Harris equilibrium. Three-dimensional PIC calculations are implemented at later stages, when fronts are fully formed. Intense currents and enhanced wave ac…
New observations and models of circumstellar CO line emission of AGB stars in the Herschel SUCCESS programme
Olofsson, H.; Teyssier, D.; García-Lario, P. +8 more
Context. Asymptotic giant branch (AGB) stars are in one of the latest evolutionary stages of low to intermediate-mass stars. Their vigorous mass loss has a significant effect on the stellar evolution, and is a significant source of heavy elements and dust grains for the interstellar medium. The mass-loss rate can be well traced by carbon monoxide …
Helium Atmospheres on Warm Neptune- and Sub-Neptune-sized Exoplanets and Applications to GJ 436b
Seager, Sara; Hu, Renyu; Yung, Yuk L.
Warm Neptune- and sub-Neptune-sized exoplanets in orbits smaller than Mercury’s are thought to have experienced extensive atmospheric evolution. Here we propose that a potential outcome of this atmospheric evolution is the formation of helium-dominated atmospheres. The hydrodynamic escape rates of Neptune- and sub-Neptune-sized exoplanets are comp…
The Morphologies of Massive Galaxies from z ~ 3—Witnessing the Two Channels of Bulge Growth
Daddi, E.; Huertas-Company, M.; Mei, S. +8 more
We quantify the morphological evolution of z∼ 0 massive galaxies ({M}*/{M}⊙ ∼ {10}11.2+/- 0.3) from z∼ 3 in the 5 CANDELS fields. The progenitors are selected using abundance matching techniques to account for the mass growth. At z\lt 1, the population matches the massive end of the Hubble sequence, with 30% of pur…
B fields in OB stars (BOB): on the detection of weak magnetic fields in the two early B-type stars β CMa and ɛ CMa. Possible lack of a "magnetic desert" in massive stars
Ilyin, I.; Carroll, T. A.; Fossati, L. +14 more
Only a small fraction of massive stars seem to host a measurable structured magnetic field, whose origin is still unknown and whose implications for stellar evolution still need to be assessed. Within the context of the "B fields in OB stars (BOB)" collaboration, we used the HARPSpol spectropolarimeter to observe the early B-type stars β CMa (HD 4…
Science objectives and performances of NOMAD, a spectrometer suite for the ExoMars TGO mission
Aoki, S.; Vandaele, A. C.; Daerden, F. +49 more
The NOMAD spectrometer suite on the ExoMars Trace Gas Orbiter will map the composition and distribution of Mars' atmospheric trace species in unprecedented detail, fulfilling many of the scientific objectives of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument is a combination of three channels, covering a spectral range f…
Identification of the High-energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State
Bogdanov, Slavko; Halpern, Jules P.
We present X-ray, ultraviolet, and optical observations of 1RXS J154439.4-112820, the most probable counterpart of the unassociated Fermi-LAT source 3FGL J1544.6-1125. The optical data reveal rapid variability, which is a feature of accreting systems. The X-rays exhibit large-amplitude variations in the form of fast switching (within ∼10 s) betwee…
On the origin of the intracluster light in massive galaxy clusters
Bradač, Maruša; Gonzalez, Anthony H.; Zaritsky, Dennis +2 more
We present a pilot study on the origin and assembly history of the intracluster starlight (ICL) for four galaxy clusters at 0.44 ≤ z ≤ 0.57 observed with the Hubble Space Telescope from the Cluster Lensing and Supernova Survey with Hubble (CLASH) sample. Using this sample of CLASH clusters we set an empirical limit on the amount of scatter in ICL …