Search Publications
Electron trapping in the coma of a weakly outgassing comet
Divin, Andrey; Deca, Jan; Olshevsky, Vyacheslav +2 more
Measurements from the Rosetta mission have shown a multitude of nonthermal electron distributions in the cometary environment, challenging the previously assumed plasma interaction mechanisms near a cometary nucleus. In this paper, we discuss electron trapping near a weakly outgassing comet from a fully kinetic (particle-in-cell) perspective. Usin…
Galaxy structural analysis with the curvature of the brightness profile
Ferrari, Fabricio; Lucatelli, Geferson
In this work, we introduce the curvature of a galaxy brightness profile to identify its structural subcomponents in a non-parametrically fashion. Bulges, bars, discs, lens, rings, and spiral arms are key to understand the formation and evolution path the galaxy undertook. Identifying them is also crucial for morphological classification of galaxie…
The kinematics of Galactic disc white dwarfs in Gaia DR2
Kilic, Mukremin; Rowell, Nicholas
We present an analysis of the kinematics of Galactic disc white dwarf (WD) stars in the solar neighbourhood using data from Gaia Data Release 2. Selection of WDs based on parallax provides the first large, kinematically unbiased sample of solar neighbourhood WDs to date. Various classical properties of the solar neighbourhood kinematics have been …
Sub-millimetre non-contaminated detection of the disc around TWA 7 by ALMA
de Gregorio-Monsalvo, I.; Bayo, A.; Schreiber, M. R. +9 more
Debris discs can be seen as the leftovers of giant planet formation and the possible nurseries of rocky planets. While M-type stars outnumber more massive stars we know very little about the time evolution of their circumstellar discs at ages older than ∼10 Myr. Sub-millimetre observations are best to provide first order estimates of the available…
Orbital and physical parameters of the close binary system GJ 9830 (HIP 116259)
Al-Wardat, Mashhoor A.; Pathan, J. M.; Masda, Suhail G.
We present the complete set of physical and geometrical parameters of the visual close binary system GJ 9830 for the first time by applying Al-Wardat’s complex method. This method combines magnitude difference from speckle interferometry, synthetic spectral energy distributions of the binary components which are constructed based on grids of Kuruc…
CO Outflow Candidates toward the W3/4/5 Complex I: The Sample and Its Spatial Distribution
Xu, Ye; Yan, Qing-Zeng; Sun, Yan +3 more
Using the Purple Mountain Observatory Delingha 13.7 m telescope, we conducted a large-scale 12CO ≤ft(J=1\to 0\right) outflow survey (over ∼110 deg2) toward the W3/4/5 complex and its surroundings. In total, 459 outflow candidates were identified. Approximately 62% (284) were located in the Perseus arm, including the W3/4/5 co…
Cassini Radio Occultation Observations of Titan's Ionosphere: The Complete Set of Electron Density Profiles
Dalba, Paul A.; Withers, Paul
Titan's ionosphere is an important component of the moon's environment. Ionospheric densities above ≈900 km have been studied with in situ measurements, but few density profiles for lower altitudes has been reported. Here we report the generation of the complete set of twenty ionospheric electron density profiles from the Cassini Radio Science Sub…
The Importance of Secondary Halos for Strong Lensing in Massive Galaxy Clusters across Redshift
Florian, Michael K.; Gladders, Michael D.; Li, Nan +6 more
Cosmological cluster-scale strong gravitational lensing probes the mass distribution of the dense cores of massive dark matter halos and the structures along the line of sight from background sources to the observer. It is frequently assumed that the primary lens mass dominates the lensing, with the contribution of secondary masses along the line …
An X-ray spectroscopic search for dark matter and unidentified line signatures in the Perseus cluster with Hitomi
Fabian, Andrew C.; Maeda, Yoshitomo; Gandhi, Poshak +14 more
The reported detection of a 3.5 keV emission signal in the Perseus cluster core by Bulbul et al. (2014, ApJ, 789, 13) was ruled out at high confidence in analysis conducted by Aharonian et al. (2017, ApJ, 837, L15) of X-ray spectra at 5 eV energy resolution obtained with the Hitomi observatory Soft X-ray Spectrometer (SXS). Using the same data, we…
Volume uncertainty assessment method of asteroid models from disc-integrated visual photometry
Bartczak, P.; Dudziński, G.
The need for more accurate asteroid models is perhaps secondary to the need to measure their quality. The uncertainties of models' parameters propagate to quantities like volume or density - the most important and informative properties of asteroids - affecting conclusions about their physical nature. Our knowledge on shapes and spins of small Sol…