Search Publications
An X-Ray Imaging Survey of Quasar Jets: The Complete Survey
Birkinshaw, M.; Worrall, D. M.; Schwartz, D. A. +8 more
We present Chandra X-ray imaging of a flux-limited sample of flat spectrum radio-emitting quasars with jet-like structure. X-rays are detected from 59% of 56 jets. No counter-jets were detected. The core spectra are fitted by power-law spectra with a photon index Γ x , whose distribution is consistent with a normal distribution, with a …
The CARMENES search for exoplanets around M dwarfs. Nine new double-line spectroscopic binary stars
Nagel, E.; Amado, P. J.; Caballero, J. A. +27 more
Context. The CARMENES spectrograph is surveying ∼300 M dwarf stars in search for exoplanets. Among the target stars, spectroscopic binary systems have been discovered, which can be used to measure fundamental properties of stars.
Aims: Using spectroscopic observations, we determine the orbital and physical properties of nine new double-line s…
The rate of Type-Ia supernovae in galaxy clusters and the delay-time distribution out to redshift 1.75
Maoz, Dan; Friedmann, Matan
The observed delay-time distribution (DTD) of Type-Ia supernovae (SNe Ia) is a valuable probe of SN Ia progenitors and physics, and of the role of SNe Ia in cosmic metal enrichment. The SN Ia rate in galaxy clusters as a function of cluster redshift is an almost-direct measure of the DTD, but current estimates have been limited out to a mean redsh…
Modulation of Galactic Cosmic Rays in the Inner Heliosphere over Solar Cycles
Qin, G.; Shen, Z. -N.
The 11- and 22-year modulation of galactic cosmic rays (GCRs) in the inner heliosphere is studied using a numerical model developed by Qin and Shen in 2017. Based on the numerical solutions of Parker’s transport equations, the model incorporates a modified Parker heliospheric magnetic field, a locally static time-delayed heliosphere, and a time-de…
Dust production and depletion in evolved planetary systems
Reach, W. T.; Gänsicke, B. T.; Pala, A. F. +15 more
The infrared dust emission from the white dwarf GD 56 is found to rise and fall by 20 per cent peak-to-peak over 11.2 yr, and is consistent with ongoing dust production and depletion. It is hypothesized that the dust is produced via collisions associated with an evolving dust disc, temporarily increasing the emitting surface of warm debris, and is…
Europa's ice-related atmosphere: The sputter contribution
Wurz, P.; Vorburger, A.
Europa, Jupiter's innermost icy satellite, is embedded well within Jupiter's magnetospheric plasma, an intense flux of ions and electrons that approximately co-rotate with Jupiter. The plasma can be thought of as consisting of two populations: The cold, thermal plasma containing charged particles with energies ranging from 1 eV to 1 keV, and the h…
The AKARI IRC asteroid flux catalogue: updated diameters and albedos
Müller, T. G.; Usui, F.; Alí-Lagoa, V. +1 more
The AKARI IRC all-sky survey provided more than twenty thousand thermal infrared observations of over five thousand asteroids. Diameters and albedos were obtained by fitting an empirically calibrated version of the standard thermal model to these data. After the publication of the flux catalogue in October 2016, our aim here is to present the AKAR…
The HST Large Programme on ω Centauri. III. Absolute Proper Motion
Milone, Antonino P.; Anderson, Jay; van der Marel, Roeland P. +11 more
In this paper, we report a new estimate of the absolute proper motion (PM) of the globular cluster NGC 5139 (ω Cen) as part of the HST large program GO-14118+14662. We analyzed a field 17 arcmin southwest of the center of ω Cen and computed PMs with epoch spans of ∼15.1 years. We employed 45 background galaxies to link our relative PMs to an absol…
Aluminium abundances in five discrete stellar populations of the globular cluster NGC 2808
D'Orazi, Valentina; Bragaglia, Angela; Carretta, Eugenio +3 more
We observed a sample of 90 red giant branch (RGB) stars in NGC 2808 using FLAMES/GIRAFFE and the high resolution grating with the set-up HR21. These stars have previous accurate atmospheric parameters and abundances of light elements. We derived aluminium abundances for them from the strong doublet Al i 8772-8773 Å as in previous works of our grou…
Spectroscopic Validation of Low-metallicity Stars from RAVE
Whitten, Devin D.; Beers, Timothy C.; Lee, Young Sun +16 more
We present results from a medium-resolution (R ∼ 2000) spectroscopic follow-up campaign of 1694 bright (V < 13.5), very metal-poor star candidates from the RAdial Velocity Experiment (RAVE). Initial selection of the low-metallicity targets was based on the stellar parameters published in RAVE Data Releases 4 and 5. Follow up was accomplished wi…