Search Publications
The spectacular cluster chain Abell 781 as observed with LOFAR, GMRT, and XMM-Newton
Brunetti, G.; Shimwell, T. W.; Gastaldello, F. +20 more
Context. A number of merging galaxy clusters show the presence of large-scale radio emission associated with the intra-cluster medium (ICM). These synchrotron sources are generally classified as radio haloes and radio relics.
Aims: Whilst it is commonly accepted that mergers play a crucial role in the formation of radio haloes and relics, not…
Scattering, absorption, and thermal emission by large cometary dust particles: Synoptic numerical solution
Agarwal, Jessica; Markkanen, Johannes
Context. Remote light scattering and thermal infrared observations provide clues about the physical properties of cometary and interplanetary dust particles. Identifying these properties will lead to a better understanding of the formation and evolution of the Solar System.
Aims: We present a numerical solution for the radiative and conductiv…
Coordinated UV and X-Ray Spectroscopic Observations of the O-type Giant ξ Per: The Connection between X-Rays and Large-scale Wind Structure
Ignace, Richard; Massa, Derck; Oskinova, Lida +1 more
We present new, contemporaneous Hubble Space Telescope STIS and XMM-Newton observations of the O7 III(n)((f)) star ξ Per. We supplement the new data with archival IUE spectra, to analyze the variability of the wind lines and X-ray flux of ξ Per. The variable wind of this star is known to have a 2.086-day periodicity. We use a simple, heuristic spo…
Modeling of the Sunspot-Associated Microwave Emission Using a New Method of DEM Inversion
Patsourakos, S.; Alissandrakis, C. E.; Bogod, V. M. +2 more
We develope a method to compute the temperature and density structure along the line of sight by inversion of the differential emission measure (DEM), under the assumptions of stratification and hydrostatic equilibrium. We apply this method to the DEM obtained from the Atmospheric Imaging Assembly (AIA) observations and use the results, together w…
Spectral Magnetic Helicity of Solar Active Regions between 2006 and 2017
Gosain, Sanjay; Brandenburg, Axel
We compute magnetic helicity and energy spectra from about 2485 patches of about 100 Mm side length on the solar surface using data from Hinode during 2006-2017. An extensive database is assembled where we list the magnetic energy and helicity, large- and small-scale magnetic helicity, mean current helicity density, fractional magnetic helicity, a…
Venus Express radio occultation observed by PRIDE
Wang, W.; Zheng, W.; Bocanegra-Bahamón, T. M. +18 more
Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption of a spacecraft carrier signal through the atmosphere of the celestial body of interest, as detected from a ground station on Earth. This technique is usually employed by the deep space tracking and communication facilities (e.g.…
Kinematics and Energetics of the EUV Waves on 11 April 2013
Srivastava, A. K.; Chen, P. F.; Uddin, Wahab +3 more
In this study, we present the observations of extreme-ultraviolet (EUV) waves associated with an M6.5 flare on 2013 April 11. The event was observed by Solar Dynamics Observatory (SDO) in different EUV channels. The flare was also associated with a halo CME and type II radio bursts. We observed both fast and slow components of the EUV wave. The sp…
C IV absorbers tracing cool gas in dense galaxy group/cluster environments
Charlton, Jane C.; Muzahid, Sowgat; Narayanan, Anand +3 more
We present analysis on three intervening H I-C IV absorption systems tracing gas within galaxy group/cluster environments, identified in the HST/COS far-UV spectra of the background quasars PG 1148 + 549 (zabs = 0.003 46), SBS 1122 + 594 (zabs = 0.004 02), and RXJ 1230.8 + 0115 (zabs = 0.005 74). The ionization mod…
Photospheric nitrogen abundances and carbon 12C/13C ratios of red giant stars
Sato, Bun'ei; Omiya, Masashi; Harakawa, Hiroki +1 more
Nitrogen abundances and carbon isotope ratios (12C/13C) in the atmospheres of red giants are known to be influenced by dredge-up of H-burning products, and serve as useful probes to study the nature of evolution-induced envelope mixing. We determined the [N/Fe] and 12C/13C ratios for 239 late-G/early-K g…
An Optical and X-Ray Study of the Contact Binary, BH Cassiopeia
Zheng, Jie; Zhang, Yu; Esamdin, Ali +10 more
We present the revised and high-quality CCD time series observations in 2017 and 2018 of the W UMa-type contact binary BH Cas. The combination of our new determinations of minimum times and those collected from the literatures reveal a long-term period increase with a rate of dP/dt = +3.27 × 10-7 day yr-1, which can be accoun…