Search Publications
Missions
Journals
Publication Years
ALMA Measurements of Circumstellar Material in the GQ Lup System
Herczeg, Gregory J.; MacGregor, Meredith A.; Wilner, David J. +7 more
We present Atacama Large Millimeter/submillimeter Array observations of the GQ Lup system, a young Sun-like star with a substellar-mass companion in a wide-separation orbit. These observations of 870 µm continuum and CO J = 3-2 line emission with beam size ∼0.″3 (∼45 au) resolve the disk of dust and gas surrounding the primary star, GQ Lup A…
The ACS survey of Galactic globular clusters - XIV. Bayesian single-population analysis of 69 globular clusters
Anderson, J.; Jefferys, W. H.; Stenning, D. C. +7 more
We use Hubble Space Telescope (HST) imaging from the ACS Treasury Survey to determine fits for single population isochrones of 69 Galactic globular clusters. Using robust Bayesian analysis techniques, we simultaneously determine ages, distances, absorptions and helium values for each cluster under the scenario of a 'single' stellar population on m…
SPIDERS: selection of spectroscopic targets using AGN candidates detected in all-sky X-ray surveys
Georgakakis, A.; Salvato, M.; Buchner, J. +19 more
SPIDERS (SPectroscopic IDentification of eROSITA Sources) is a Sloan Digital Sky Survey IV (SDSS-IV) survey running in parallel to the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) cosmology project. SPIDERS will obtain optical spectroscopy for large numbers of X-ray-selected active galactic nuclei (AGN) and galaxy cluster members detec…
The Solar Energetic Particle Event of 2010 August 14: Connectivity with the Solar Source Inferred from Multiple Spacecraft Observations and Modeling
Thompson, B. J.; Lario, D.; Kwon, R. -Y. +13 more
We analyze one of the first solar energetic particle (SEP) events of solar cycle 24 observed at widely separated spacecraft in order to assess the reliability of models currently used to determine the connectivity between the sources of SEPs at the Sun and spacecraft in the inner heliosphere. This SEP event was observed on 2010 August 14 by near-E…
Constraining neutrino mass and extra relativistic degrees of freedom in dynamical dark energy models using Planck 2015 data in combination with low-redshift cosmological probes: basic extensions to ΛCDM cosmology
Zhang, Jing-Fei; Zhang, Xin; Li, Yun-He +1 more
We investigate how the properties of dark energy affect the cosmological measurements of neutrino mass and extra relativistic degrees of freedom. We limit ourselves to the most basic extensions of Λ cold dark matter (CDM) model, I.e. the wCDM model with one additional parameter w, and the w0waCDM model with two additional par…
Hertzsprung-Russell diagram and mass distribution of barium stars
Jorissen, A.; Pourbaix, D.; Escorza, A. +6 more
With the availability of parallaxes provided by the Tycho-Gaia Astrometric Solution, it is possible to construct the Hertzsprung-Russell diagram (HRD) of barium and related stars with unprecedented accuracy. A direct result from the derived HRD is that subgiant CH stars occupy the same region as barium dwarfs, contrary to what their designations i…
A Comet Active Beyond the Crystallization Zone
Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more
We present observations showing inbound long-period comet C/2017 K2 (PANSTARRS) to be active at a record heliocentric distance. Nucleus temperatures are too low (60-70 K) either for water ice to sublimate or for amorphous ice to crystallize, requiring another source for the observed activity. Using the Hubble Space Telescope we find a sharply boun…
Hybrid modelling of cometary plasma environments. I. Impact of photoionisation, charge exchange, and electron ionisation on bow shock and cometopause at 67P/Churyumov-Gerasimenko
Kallio, E.; Gunell, H.; Behar, E. +7 more
Context. The ESA/Rosetta mission made it possible to monitor the plasma environment of a comet, from near aphelion to perihelion conditions. To understand the complex dynamics and plasma structures found at the comet, a modelling effort must be carried out in parallel.
Aims: Firstly, we present a 3D hybrid model of the cometary plasma environ…
Astrochemical Properties of Planck Cold Clumps
Sanhueza, Patricio; Choi, Minho; Di Francesco, James +26 more
We observed 13 Planck cold clumps with the James Clerk Maxwell Telescope/SCUBA-2 and with the Nobeyama 45 m radio telescope. The N2H+ distribution obtained with the Nobeyama telescope is quite similar to SCUBA-2 dust distribution. The 82 GHz HC3N, 82 GHz CCS, and 94 GHz CCS emission are often distributed differentl…
A Parameter Study for Modeling Mg II h and k Emission during Solar Flares
Kleint, Lucia; Rubio da Costa, Fatima
Solar flares show highly unusual spectra in which the thermodynamic conditions of the solar atmosphere are encoded. Current models are unable to fully reproduce the spectroscopic flare observations, especially the single-peaked spectral profiles of the Mg II h and k lines. We aim to understand the formation of the chromospheric and optically thick…