23 papers
X-ray and Hα superflare on an RS CVn-type star, UX Arietis: Constraint on the flare location from radial velocity change during the flare
Sota Urabe, Yohko Tsuboi, Kosuke Namekata +5
We report on a giant stellar flare from the RS CVn-type binary UX Arietis, detected with the Monitor of All-sky X-ray Image (MAXI) and followed by a 12-day optical spectroscopic ca…
Magnetic-field Order in the Southwestern Rim of RCW 86 Constrained Using X-Ray Polarimetry
Stefano Silvestri, Dmitry Prokhorov, Jacco Vink +97
RCW 86 is a supernova remnant whose origin has recently been linked to an off-center explosion within a cavity created by its progenitor star. In the southwestern region, the forwa…
In-orbit Demonstration of X-ray Pulsar Navigation with NinjaSat
Naoyuki Ota, Takuya Takahashi, Toru Tamagawa +26
This study demonstrated the pulsar navigation capability of the CubeSat X-ray observatory NinjaSat, which is equipped with two Gas Multiplier Counters (GMCs). The GMCs are sensitiv…
Polarization of reflected X-ray emission from the Sgr A molecular complex: multiple flares, multiple sources?
Ildar Khabibullin, Eugene Churazov, Riccardo Ferrazzoli +100
The extended X-ray emission observed in the direction of several molecular clouds in the central molecular zone of our Galaxy exhibits spectral and temporal properties consistent w…
Eclipsing Stellar Flare on the Demon Star Algol Binary System Observed during the MAXI-NICER Follow-up Campaign in 2018
Kazuya Nakayama, Wataru Buz Iwakiri, Teruaki Enoto +6
Algol is a well-known eclipsing binary hosting an active and variable star that exhibits frequent stellar flares. Here, we report our pre-planned and coordinated rapid X-ray follow…
Super-Eddington Accretion Geometry: a Remarkable Stability of the Hidden Ultraluminous X-Ray Source Cygnus X-3
Romana Mikušincová, Alexandra Veledina, Fabio Muleri +112
We report on the average and orbital phase-resolved polarization of Cyg X-3 in the hard state during the 2023 Imaging X-ray Polarimetry Explorer (IXPE) observational campaign. We f…