Search Publications
On the Origin of Inner Coma Structures Observed by Rosetta during a Diurnal Rotation of Comet 67P/Churyumov--Gerasimenko.
Kramer, Tobias; Noack, Matthias
The Rosetta probe around comet 67P/Churyumov-Gerasimenko (67P) reveals an anisotropic dust distribution of the inner coma with jet-like structures. The physical processes leading to jet formation are under debate, with most models for cometary activity focusing on localized emission sources, such as cliffs or terraced regions. Here we suggest, by …
Discovery of γ-Ray Emission from the Radio-intermediate Quasar III Zw 2: Violent Jet Activity with Intraday γ-Ray Variability
Weng, Shan-Shan; Chen, Liang; Fan, Yi-Zhong +4 more
III Zw 2 is the prototype of radio-intermediate quasars. Although there is the evidence of possessing strong jet, significant γ-ray emission has not been reported before. In this work, we carry out a detailed analysis of the latest Fermi-LAT Pass 8 data. No significant γ-ray signal has been detected in the time-averaged 7-year Fermi-LAT data of II…
Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters. I. Statistical and Computational Methods
Stenning, D. C.; Wagner-Kaiser, R.; Robinson, E. +4 more
We develop a Bayesian model for globular clusters composed of multiple stellar populations, extending earlier statistical models for open clusters composed of simple (single) stellar populations. Specifically, we model globular clusters with two populations that differ in helium abundance. Our model assumes a hierarchical structuring of the parame…
N131: A dust bubble born from the disruption of a gas filament
Zhang, Chuan-Peng; Li, Guang-Xing; Wyrowski, Friedrich +6 more
Context. OB-type stars have strong ionizing radiation and drive energetic winds. The ultraviolet radiation from ionizing stars may heat dust and ionize gas to sweep up an expanding bubble shell. This shell may be the result of feedback leading to a new generation of stars.
Aims: N131 is an infrared dust bubble residing in a molecular filament…
Weighing Stars: The Identification of an Evolved Blue Straggler Star in the Globular Cluster 47 Tucanae
Dalessandro, E.; Massari, D.; Mucciarelli, A. +4 more
Globular clusters are known to host peculiar objects named blue straggler stars (BSSs), significantly heavier than the normal stellar population. While these stars can be easily identified during their core hydrogen-burning phase, they are photometrically indistinguishable from their low-mass sisters in advanced stages of the subsequent evolution.…
Simulations of Alfvén and Kink Wave Driving of the Solar Chromosphere: Efficient Heating and Spicule Launching
Arber, T. D.; Brady, C. S.
Two of the central problems in our understanding of the solar chromosphere are how the upper chromosphere is heated and what drives spicules. Estimates of the required chromospheric heating, based on radiative and conductive losses, suggest a rate of ∼0.1 erg cm-3 s-1 in the lower chromosphere and drops to ∼10-3 er…
On the estimation of stellar parameters with uncertainty prediction from Generative Artificial Neural Networks: application to Gaia RVS simulated spectra
Allende Prieto, C.; Garabato, D.; Álvarez, M. A. +4 more
Aims: We present an innovative artificial neural network (ANN) architecture, called Generative ANN (GANN), that computes the forward model, that is it learns the function that relates the unknown outputs (stellar atmospheric parameters, in this case) to the given inputs (spectra). Such a model can be integrated in a Bayesian framework to esti…
Interactions between magnetosonic waves and ring current protons: Gyroaveraged test particle simulations
Zhang, Hui; Huang, Shiyong; Fu, Song +6 more
Gyroaveraged test particle simulations are implemented to quantitatively investigate interactions between linearly polarized magnetosonic waves (i.e., equatorial noises) and ring current protons inside and outside the plasmasphere at L = 4.5. For magnetosonic waves at the frequency of 33.3 Hz (fw/fcp = 6.4 at the magnetic equ…
The Gigaelectronvolt Counterpart of VER J2019+407 in the Northern Shell of the Supernova Remnant G78.2+2.1 (γ Cygni)
Fraija, N.; Araya, M.
Analysis of gamma-ray emission from the supernova remnant G78.2+2.1 (γ Cygni) with 7.2 years of cumulative data from the Fermi Large Area Telescope shows a distinct hard, bright, and extended component to the north of the shell coincident with the known teraelectronvolt source VER J2019+407. In the gigaelectronvolt to teraelectronvolt (GeV-TeV) en…
Merging Galaxies with Tidal Tails in COSMOS to z = 1
Zheng, Xian Zhong; Wen, Zhang Zheng
Tidal tails are created in major mergers involving disk galaxies. It remains to be explored how the tidal tails trace the assembly history of massive galaxies. We identify a sample of 461 merging galaxies with long tidal tails, from 35,076 galaxies mass-complete at {M}\star ≥slant {10}9.5 {M}⊙ and 0.2≤slant z≤slan…