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The Space Weather Context of the First Extreme Event of Solar Cycle 25, on 2022 September 5
Vourlidas, Angelos; Kouloumvakos, Athanasios; Papaioannou, Athanasios +3 more
The coronal mass ejection (CME) on 2022 September 5 was the fastest CME yet observed and measured in situ by a spacecraft inside the corona (0.06 au for the Parker Solar Probe). Here we assess the significance of this event for space weather studies by analyzing the source region characteristics and its temporal evolution via a magnetic complexity…
Magnetic Fields and Fragmentation of Filaments in the Hub of California-X
Kwon, Woojin; Soam, Archana; Cho, Jungyeon +4 more
We present 850 µm polarization and C18O (3-2) molecular line observations toward the X-shaped nebula in the California molecular cloud using James Clerk Maxwell Telescope (JCMT)'s SCUBA-2/POL-2 and HARP instruments. The 850 µm emission shows that the observed region includes two elongated filamentary structures (Fil1 and Fil…
Further evidence of the link between activity and metallicity using the flaring properties of stars in the Kepler field
Amard, Louis; See, Victor; Roquette, Julia +1 more
The magnetic activity level of low-mass stars is known to vary as a function of the physical properties of the star. Many studies have shown that the stellar mass and rotation are both important parameters that determine magnetic activity levels. In contrast, the impact of a star's chemical composition on magnetic activity has received comparative…
Deuterated Polycyclic Aromatic Hydrocarbons in the Interstellar Medium: The Aliphatic C-D Band Strengths
Li, Aigen; Yang, X. J.
Deuterium (D) was exclusively generated in the Big Bang, and the standard Big Bang nucleosynthesis (BBN) model predicts a primordial abundance of D/H ≈ 26 parts per million (ppm). As the Galaxy evolves, D/H gradually decreases because of astration. The Galactic chemical evolution (GCE) model predicts a present-day abundance of D/H ≳ 20 ppm. Howeve…
Three-dimensional relation between coronal dimming, filament eruption, and CME. A case study of the 28 October 2021 X1.0 event
Veronig, Astrid M.; Dumbović, Mateja; Temmer, Manuela +4 more
Context. Coronal dimmings are localized regions of reduced emission in the extreme-ultraviolet (EUV) and soft X-rays formed as a result of the expansion and mass loss by coronal mass ejections (CMEs) low in the corona. Distinct relations have been established between coronal dimmings (intensity, area, magnetic flux) and key characteristics of the …
Hard X-Ray Observation and Multiwavelength Study of the PeVatron Candidate Pulsar Wind Nebula "Dragonfly"
Woo, Jooyun; An, Hongjun; Gelfand, Joseph D. +5 more
We studied the PeVatron nature of the pulsar wind nebula (PWN) G75.2+0.1 ("Dragonfly") as part of our NuSTAR observational campaign of energetic PWNe. The Dragonfly is spatially coincident with LHAASO J2018+3651, whose maximum photon energy is 0.27 PeV. We detected a compact (radius $1^{\prime} $ ) inner nebula of the Dragonfly without a spectral …
Multipoint Turbulence Analysis with HelioSwarm
Servidio, Sergio; Pecora, Francesco; Primavera, Leonardo +3 more
Exploration of plasma dynamics in space, including turbulence, is entering a new era of multisatellite constellation measurements that will determine fundamental properties with unprecedented precision. Familiar but imprecise approximations will need to be abandoned and replaced with more-advanced approaches. We present a preparatory study of the …
Star Formation in the Dwarf Seyfert Galaxy NGC 4395: Evidence for Both AGN and SN Feedback?
Stalin, C. S.; Nandi, Payel; Saikia, D. J. +5 more
We present a detailed multiwavelength study of star formation in the dwarf galaxy NGC 4395, which hosts an active galactic nucleus (AGN). From our observations with the Ultra-Violet Imaging Telescope, we have compiled a catalog of 284 star-forming (SF) regions, out of which we could detect 120 SF regions in Hα observations. Across the entire galax…
Multithermal Jet Formation Triggered by Flux Emergence
Li, Xiaohong; Keppens, Rony; Zhou, Yuhao
Flux emergence is responsible for various solar eruptions. Combining observation and simulations, we investigate the influence of flux emergence at one footpoint of an arcade on coronal rain as well as induced eruptions. The emergence changes the pressure in the loops, and the internal coronal rain all moves to the other side. The emerging flux re…
Investigating the amplitude and rotation of the phase spiral in the Milky Way outer disc
McMillan, P. J.; Bensby, T.; Alinder, S.
Context. With data releases from the astrometric space mission Gaia, exploration of the structure of the Milky Way is now possible in unprecedented detail, and has unveiled many previously unknown structures in the Galactic disc and halo. One such feature is the Gaia phase spiral where the stars in the Galactic disc form a spiral density pattern i…