Search Publications
Evidence of Kelvin-Helmholtz and tearing mode instabilities at the magnetopause during space weather events
Jerse, Giovanna; Marcucci, Maria Federica; Laurenza, Monica +9 more
Introduction: Kelvin-Helmholtz (KH) and tearing mode (TM) instabilities are one of the most important mechanisms of solar wind energy, momentum and plasma transport within the magnetosphere.Methods: To investigate the conditions under which KHTM instabilities occur in the Earth environment it is fundamental to combine simultaneous multipoint in si…
A Possible X-ray Quasi-periodic Oscillation in the Narrow-line Seyfert 1 Galaxy Mrk 142
Zhong, Xiao-Gu; Wang, Jian-Cheng; Chen, Yong-Yun +1 more
A possible quasi-periodic oscillation (QPO) at frequency 7.045 × 10‑5 Hz is found in the narrow-line Seyfert 1 galaxy Mrk 142 in the data of XMM-Newton collected on 2020 April 11. We find that the QPO signal is statistically significantly larger than the 5σ level and highly coherent with quality factor Q > 5 at the 0.3–10 keV band by…
New Results of Radiation Study on Board TGO ExoMars in 2018–2023
Mitrofanov, I.; Golovin, D.; Kozyrev, A. +13 more
The article provides a brief description of the Liulin-MO dosimeter, which is part of the FREND (Fine Resolution Epithermal Neutron Detector) device installed on the TGO (Trace Gas Orbiter) spacecraft of the ExoMars-2016 mission. Since April 2018, TGO has been operating in orbit around Mars. Data are presented on the radiation environment in the o…
X-Ray, UV, and Optical Observations of Proxima Centauri's Stellar Cycle
Slavin, Jonathan D.; do Nascimento, José-Dias; Saar, Steven H. +3 more
Proxima Cen (GJ 551; dM5.5e) is one of only about a dozen fully convective stars known to have a stellar cycle, and the only one to have long-term X-ray monitoring. A previous analysis found that X-ray and mid-UV observations, particularly two epochs of data from Swift, were consistent with a well-sampled ∼7 yr optical cycle seen in All Sky Automa…
A survey for variable young stars with small telescopes - IX. Evolution of spot properties on YSOs in IC 5070
Scholz, Aleks; Eislöffel, Jochen; Dvorak, Shawn +45 more
We present spot properties on 32 periodic young stellar objects in IC 5070. Long term, ~5 yr, light curves in the V, R, and I-bands are obtained through the HOYS (Hunting Outbursting Young Stars) citizen science project. These are dissected into 6 months long slices, with 3 months oversampling, to measure 234 sets of amplitudes in all filters. We …
The first low-mass eclipsing binary within the fully convective zone from TMTS
Kovalev, Mikhail; Zhu, Liying; Wang, Xiaofeng +17 more
We present a comprehensive photometric and spectroscopic analysis of the short-period (~5.32 h) and low-mass eclipsing binary TMTSJ0803 discovered by Tsinghua-Ma Huateng Telescope for Survey (TMTS). By fitting the light curves and radial velocity data with the Wilson-Devinney code, we find that the binary is composed of two late spotted active M d…
A Very-High-Energy Gamma-Ray View of the Transient Sky
Carosi, Alessandro; López-Oramas, Alicia
The development of the latest generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) over recent decades has led to the discovery of new extreme astrophysical phenomena in the very-high-energy (VHE, E > 100 GeV) gamma-ray regime. Time-domain and multi-messenger astronomy are inevitably connected to the physics of transient VHE emitters,…
Is the Young Star Association ϵ Cha Double?
Bobylev, V. V.; Bajkova, A. T.
The kinematics of the ϵ Cha young stellar association close to the Sun has been studied based on a list of candidate stars from the Dickson-Vandervelde et al. work. The working sample consists of 26 stars with parallaxes, proper motions from the Gaia DR3 catalog and radial velocities taken from literary sources. The orbits of the stars back to the…
XUV irradiation of young planetary atmospheres. Results from a joint XMM-Newton and HST observation of HIP67522
Micela, G.; Benatti, S.; Pillitteri, I. +3 more
Context. The evaporation and the chemistry of the atmospheres of warm and hot planets are strongly determined by the high-energy irradiation they receive from their parent stars. This is more crucial among young extra-solar systems because of the high activity of stars at early ages. In particular, the extreme-ultraviolet (EUV) part of the stellar…
An X-Ray Significantly Variable, Luminous, Type 2 Quasar at z = 2.99 with a Massive Host Galaxy
Marchesi, Stefano; Gilli, Roberto; Zhao, Xiurui +8 more
We present a comprehensive X-ray analysis and spectral energy distribution (SED) fitting of WISEA J171419.96+602724.6, an extremely luminous type 2 quasar at z = 2.99. The source was suggested as a candidate Compton-thick (column density N H > 1.5×1024 cm‑2) quasar by a short XMM-Newton observation in 2011. We r…