Search Publications
NuSTAR and XMM-Newton observations of the binary 4FGL J1405.1-6119. A γ-ray-emitting microquasar?
Fogantini, Federico A.; Combi, Jorge A.; Romero, Gustavo E. +3 more
Context. 4FGL J1405.1−6119 is a high-mass γ-ray-emitting binary that has been studied at several wavelengths. The nature of this type of binary is still under debate, with three possible scenarios usually invoked to explain the origin of the γ-ray emission: collisions between the winds of a rapidly rotating neutron star and its companion, collisio…
Solar Wind Protons Forming Partial Ring Distributions at Comet 67P
Gunell, H.; Nilsson, H.; Richter, I. +5 more
We present partial ring distributions of solar wind protons observed by the Rosetta spacecraft at comet 67P/Churyumov-Gerasimenko. The formation of ring distributions is usually associated with high activity comets, where the spatial scales are larger than multiple ion gyroradii. Our observations are made at a low-activity comet at a heliocentric …
Interpretation of Flat Energy Spectra Upstream of Fast Interplanetary Shocks
Zimbardo, Gaetano; Servidio, Sergio; Wilson, Lynn B., III +6 more
Interplanetary shocks are large-scale heliospheric structures often caused by eruptive phenomena at the Sun, and represent one of the main sources of energetic particles. Several interplanetary (IP) shock crossings by spacecraft at 1 au have revealed enhanced energetic-ion fluxes that extend far upstream of the shock. Surprisingly, in some shock e…
A rare outburst from the stealthy BeXRB system Swift J0549.7-6812
Udalski, A.; Coe, M. J.; Kennea, J. A. +3 more
Swift J0549.7-6812 is a Be/X-ray binary system (BeXRB) in the Large Magellanic Cloud (LMC) exhibiting an ~6 s pulse period. Like many such systems, the variable X-ray emission is believed to be driven by the underlying behaviour of the mass donor Be star. In this paper, we report on X-ray observations of the brightest known outburst from this syst…
The Messy Nature of Fiber Spectra: Star-Quasar Pairs Masquerading as Dual Type 1 AGNs
Bohn, Thomas; Pfeifle, Ryan W.; Secrest, Nathan J. +5 more
Theoretical studies predict that the most significant growth of supermassive black holes (SMBHs) occurs in late-stage mergers, coinciding with the manifestation of dual active galactic nuclei (AGNs), and both major and minor mergers are expected to be important for dual AGN growth. In fact, dual AGNs in minor mergers should be signposts for effici…
Determination of the Spiral Pattern Speed in the Milky Way from Young Open Star Clusters
Bobylev, V. V.; Bajkova, A. T.
We have estimated the spiral pattern speed in the Galaxy $Ωp$ from a large sample of young open star clusters (OSCs). For this purpose, we have used 2494 OSCs younger than 50 Myr. Their mean proper motions, line-of-sight velocities, and distances were calculated by Hunt and Reffert (2023) based on data from the Gaia DR3 catalogue. Three…
Revisiting mirror modes in the plasma environment of comet 67P/Churyumov-Gerasimenko
Goetz, Charlotte; Volwerk, Martin; Tello Fallau, Ariel +2 more
The plasma environment of comet 67P provides a unique laboratory to study plasma phenomena in the interplanetary medium. There, waves are generated which help the plasma relax back to stability through wave-particle interactions, transferring energy from the wave to the particles and vice versa. In this study, we focus on mirror-mode-like structur…
Splitting and Reconstruction of a Solar Filament Caused by Magnetic Emergence and Reconnection
Xu, Zhe; Xue, Zhike; Yan, Xiaoli +4 more
We present observations and interpretation of a nonerupting filament in NOAA active region (AR) 12827 that undergoes splitting and restructuring on 2021 June 4, using the high-resolution data obtained by the New Vacuum Solar Telescope, the Solar Dynamics Observatory, and the Interface Region Imaging Spectrograph. At the beginning, the right footpo…
CMR Exploration. I. Filament Structure with Synthetic Observations
Klessen, Ralf S.; Arce, Héctor G.; Kong, Shuo +2 more
In this paper, we carry out a pilot parameter exploration for the collision-induced magnetic reconnection (CMR) mechanism that forms filamentary molecular clouds. Following Kong et al., we utilize Athena++ to model CMR in the context of resistive magnetohydrodynamics (MHD), considering the effect from seven physical conditions, including the ohmic…
A Broadband X-Ray Study of the Dwarf Nova SS Cyg during Quiescence and Outburst
Mukai, Koji; Dutta, Anirban; Rana, Vikram +1 more
We present a broadband X-ray study (~0.3-50 keV) of the dwarf nova SS Cyg highlighting the changes in the accretion during two phases, the quiescence and the outburst states. The investigation was based on simultaneous observations carried out with the XMM-Newton and NuSTAR telescopes in two epochs, involving medium- and high-resolution spectrosco…