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Thermal and non-thermal X-ray emission from stellar clusters and superbubbles
Kavanagh, Patrick J.
Massive stellar clusters inject significant mass and energy into their surroundings driving superbubbles, 100–1000 pc diameter shells of swept-up interstellar material that contain a hot (
The 21 µm and 30 µm emission features in carbon-rich objects
Volk, Kevin; Sloan, G. C.; Kraemer, Kathleen E.
We review the observational properties and possible carriers of the 21 and 30 µm features seen in the spectra of evolved carbon-rich objects. The 30 µm feature is generally taken to be due to MgS, possibly in combination with other sulfides. It is commonly assumed that the sulfides coat grains of SiC or amorphous carbon, but it remains…
5D memberships and fundamental properties of the old open cluster NGC 6791 based on Gaia
Gao, Xinhua
This paper investigates reliable memberships and fundamental astrophysical properties of the old (∼8 Gyr) open cluster NGC 6791 using the astrometric and photometric data of the Gaia data release 2 (
Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT
Li, Gang; Li, Xiaobo; Tuo, Youli +10 more
Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, i…
Distance scale for high-luminosity stars in OB associations and in field with Gaia DR2. Spurious systematic motions
Melnik, A. M.; Dambis, A. K.
We calculated the median parallaxes for 47 OB associations including at least 10 stars with known Gaia DR2 parallaxes. A comparison between trigonometric and photometric parallaxes of OB associations reveals a zero-point offset of
Hydrogenated fullerenes (fulleranes) in space
Zhang, Yong; Hsia, Chih-Hao; Sadjadi, Seyedabdolreza
Since the first laboratory synthesis of C60 in 1985, fullerene-related species have been proposed to interpret various astronomical features. After more than 25 years' efforts, several circumstellar and interstellar features have been convincingly assigned to C60, C70, and C
Investigation of ionospheric TEC anomalies caused by space weather conditions
Alcay, Salih; Gungor, Merve
This study examines the influence of space weather conditions on ionospheric TEC variations at different latitudes around the world. According to the space weather condition indices (geomagnetic storm-activity indices, solar activity indices, magnetic field change indices, plasma density and proton flux indices) different time periods were chosen.…
Dipolar and Kelvin-Stuart's cat's eyes vortices in magnetoplasmas with non-Maxwellian electron distribution
Masood, W.; Naeem, Ismat; Mirza, Arshad M.
Linear and nonlinear propagation characteristics of drift ion acoustic waves are analyzed in an inhomogeneous plasma comprising of warm ions having shear flow parallel to the magnetic field and electrons that are followed by a distribution which is dictated by spectral indices,
New H I observations of KK 69. Is KK 69 a dwarf galaxy in transition?
Koribalski, B. S.; Benaglia, P.; Saponara, J. +1 more
We present new H I data of the dwarf galaxy KK 69, obtained with the Giant Metrewave Radio Telescope (GMRT) with a signal-to-noise ratio almost double previous observations. We carried out a Gaussian spectral decomposition and stacking methods to identify the cold neutral medium (CNM) and the warm neutral medium (WNM) of the H I gas. We found that…
Exhaustive study of three-time periods of solar activity due to single active regions: sunspot, flare, CME, and geo-effectiveness characteristics
Soni, Shirsh Lata; Yadav, Manohar Lal; Gupta, Radhe Syam +1 more
In this paper, we present the multi-wavelength study of a high level of solar activity during which a single active region produced multiple flares/CMEs. According to the sunspot observations, the current solar cycle 24 manifest to be less intense in comparison with the previous recent sunspot cycles. In the course of the current sunspot cycle 24,…