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Simultaneous X-ray and optical variability of M dwarfs observed with eROSITA and TESS
Stelzer, B.; Magaudda, E.; Joseph, W. M. +1 more
Context. M-dwarf stars are the most numerous stars in the Galaxy, and are highly magnetically active. They exhibit bursts of radiation and matter, called flares and coronal mass ejections which have the potential to strongly affect the habitability of their planets.
Aims: We investigate variability through simultaneous optical and X-ray obser…
Mg II h&k spectra of an enhanced network region simulated with the MURaM-ChE code: Results using 1.5D synthesis
Solanki, S. K.; Leenaarts, J.; Cameron, R. +3 more
Context. The Mg II h&k lines are key diagnostics of the solar chromosphere. They are sensitive to the temperature, density, and nonthermal velocities in the chromosphere. The average Mg II h&k line profiles arising from previous 3D chromospheric simulations are too narrow compared to observations. Aims. We study the formation and properties of the…
eRASSU J060839.5-704014: A double degenerate ultra-compact binary in the direction of the LMC
Haberl, F.; Rau, A.; Vasilopoulos, G. +7 more
Context. During four all-sky surveys (eRASS1-4), eROSITA, the soft X-ray instrument aboard Spektrum-Roentgen-Gamma (SRG) detected a new supersoft X-ray source, eRASSU J060839.5−704014, in the direction of the Large Magellanic Cloud (LMC).
Aims: We arranged follow-up observations in the X-ray and optical wavelengths and further searched in arc…
Offset of M54 from the Sagittarius dwarf spheroidal galaxy
Pace, Andrew B.; Walker, Matthew G.; An, Zhaozhou
We present results from simultaneous modelling of 2D (projected along the line of sight) position, proper motion, and line-of-sight velocity for Gaia- and Apache Point Observatory Galactic Evolution Experiment (APOGEE)-observed stars near the centre of the Sagittarius (Sgr) dwarf spheroidal galaxy. We use a mixture model that allows for independen…
Constraints on the ultra-high energy cosmic ray output of gamma-ray bursts
Gendre, B.; Orange, N. B.; Moore, E. +1 more
Ultra-high energy cosmic rays are the most extreme energetic particles detected on Earth, however, their acceleration sites are still mysterious. We explore the contribution of low-luminosity gamma-ray bursts to the ultra-high energy cosmic ray flux, since they form the bulk of the nearby population. We analyse a representative sample of these bur…
Structure and dynamics of the Hermean magnetosphere revealed by electron observations from the Mercury electron analyzer after the first three Mercury flybys of BepiColombo
André, N.; Fedorov, A.; Sauvaud, J. -A. +16 more
Context. The Mercury electron analyzer (MEA) obtained new electron observations during the first three Mercury flybys by BepiColombo on October 1, 2021 (MFB1), June 23 , 2022 (MFB2), and June 19, 2023 (MFB3). BepiColombo entered the dusk side magnetotail from the flank magnetosheath in the northern hemisphere, crossed the Mercury solar orbital equ…
Discovery of Astrometric Accelerations by Dark Companions in the Globular Cluster ω Centauri
Kamann, Sebastian; Girardi, Léo; Kozhurina-Platais, Vera +6 more
We present results from the search for astrometric accelerations of stars in ω Centauri using 13 yr of regularly scheduled Hubble Space Telescope WFC3/UVIS calibration observations in the cluster core. The high-precision astrometry of ∼160,000 sources was searched for significant deviations from linear proper motion. This led to the discovery of f…
A combined LOFAR and XMM-Newton analysis of the disturbed cluster PSZ2G113.91-37.01
Brunetti, G.; Rossetti, M.; Gastaldello, F. +10 more
In this work, we investigate the interplay between the X-ray and radio emission of the cluster PSZ2G113.91-37.01 (z = 0.371) using the high-quality XMM-Newton observations of the Cluster HEritage project with XMM-Newton - Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE), and the images from the second data releas…
A Long-duration Superflare on the K Giant HD 251108
Schmitt, J. H. M. M.; Notsu, Yuta; Maehara, Hiroyuki +10 more
Many giant stars are magnetically active, which causes rotational variability, chromospheric emission lines, and X-ray emission. Large outbursts in these emission features can set limits on the magnetic field strength and thus constrain the mechanism of the underlying dynamo. HD 251108 is a Li-rich active K-type giant. We find a rotational period …
Time Series of Magnetic Field Parameters of Merged MDI and HMI Space-weather Active Region Patches as Potential Tool for Solar Flare Forecasting
Kosovichev, Alexander G.; Nita, Gelu M.; Sadykov, Viacheslav M. +8 more
Solar flare prediction studies have been recently conducted with the use of Space-Weather MDI (Michelson Doppler Imager on board Solar and Heliospheric Observatory) Active Region Patches (SMARPs) and Space-Weather HMI (Helioseismic and Magnetic Imager on board Solar Dynamics Observatory) Active Region Patches (SHARPs), which are two currently avai…