Search Publications
Time-lapse Very Long Baseline Interferometry Imaging of the Close Active Binary HR 1099
Golay, Walter W.; Mutel, Robert L.; Abbuhl, Evan E.
We report multiepoch astrometric very long baseline interferometry observations of the chromospherically active binary HR 1099 (V711 Tau, HD 22468) at six epochs over 63 days using the Very Long Baseline Array at 22.2 GHz. We determined hourly radio positions at each epoch with a positional uncertainty significantly smaller than the component sepa…
Progenitor Constraint-incorporating Shell Merger: The Case of Supernova Remnant G359.0–0.9
Sato, Toshiki; Uchida, Hiroyuki; Tsuru, Takeshi Go +5 more
It is generally hard to put robust constraints on progenitor masses of supernovae and supernova remnants (SNRs) observationally, while they offer tantalizing clues to understanding explosion mechanisms and mass distribution. Our recent study suggests that "shell merger," which is theoretically expected for stellar evolution, can appreciably affect…
Star Formation, Nebulae, and Active Galactic Nuclei in CLASH Brightest Cluster Galaxies. I. Dependence on Core Entropy of Intracluster Medium
Donahue, Megan; Ohyama, Youichi; Lim, Jeremy +2 more
We set the stage for reassessing how star formation, emission-line nebulae, and active galactic nuclei (AGNs) in brightest cluster galaxies (BCGs) depend on the thermodynamics of the intracluster medium (ICM). Our work is based on the 25 clusters observed in the CLASH program for which the aforementioned attributes in their BCGs can be well scruti…
An Eddington-limited Accretion Disk Wind in the Narrow-line Seyfert 1 PG 1448+273
Porquet, D.; Reeves, J. N.; Braito, V. +5 more
PG 1448+273 is a luminous, nearby (z = 0.0645), narrow-line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. Previous X-ray observations of PG 1448+273 with XMM-Newton in 2017 and NuSTAR in 2022 revealed the presence of an ultrafast outflow, as seen through its blueshifted iron (Fe) K absorption profile, where the outflow velo…
Interaction between a Coronal Mass Ejection and Comet 67P/Churyumov–Gerasimenko
Gombosi, Tamas I.; Combi, Michael R.; Altwegg, Kathrin +6 more
The interaction between a coronal mass ejection (CME) and a comet has been observed several times by in situ observations from the Rosetta Plasma Consortium, which is designed to investigate the cometary magnetosphere of comet 67P/Churyumov–Gerasimenko (CG). Goetz et al. reported a magnetic field of up to 300 nT measured in the inner coma, which i…
JCMT 850 µm Continuum Observations of Density Structures in the G35 Molecular Complex
Tsai, Chao-Wei; Sanhueza, Patricio; Tej, Anandmayee +32 more
Filaments are believed to play a key role in high-mass star formation. We present a systematic study of the filaments and their hosting clumps in the G35 molecular complex using James Clerk Maxwell Telescope SCUBA-2 850 µm continuum data. We identified five clouds in the complex and 91 filaments within them, some of which form 10 hub–filamen…
131 and 304 Å Emission Variability Increases Hours Prior to Solar Flare Onset
Mason, E. I.; Uritsky, Vadim M.; Kniezewski, Kara L. +1 more
Thermal changes in coronal loops are well studied, both in quiescent active regions and in flaring scenarios. However, relatively little attention has been paid to loop emission in the hours before the onset of a solar flare; here, we present the findings of a study of over 50 off-limb flares of Geostationary Operational Environmental Satellite cl…
Time Variation of the Solar Tachocline
Basu, Sarbani; Korzennik, Sylvain G.; Andrade de Aguiar, Wesley Antônio Machado
We have used solar oscillation frequencies and frequency splittings obtained over solar cycles 23 and 24 and the rising phase of solar cycle 25 to investigate whether the tachocline properties (the change in the rotation rate across the tachocline. i.e., the jump, the width, and the position) show any time variation. We confirm that the change in …
2017 Outburst of H 1743–322: AstroSat and Swift View
Dewangan, G. C.; Chand, Swadesh; Tripathi, Prakash +4 more
We perform a comprehensive timing and broadband spectral analysis using an AstroSat observation of the low-mass black hole X-ray binary H 1743–322 during its 2017 outburst. Additionally, we use two Swift/XRT observations, one of which is simultaneous with AstroSat and the other taken three days earlier, for timing analysis. The hardness–intensity …
Supernova Shocks in Molecular Clouds: Shocks Driven into Dense Cores in IC 443 and 3C 391
Tram, Le Ngoc; Reach, William T.; Godard, Benjamin +3 more
Supernova shocks into dense molecular cores in IC 443 (clumps B, C, and G) and 3C 391 were observed using the Stratospheric Observatory for Infrared Astronomy and complemented by archival data from the Herschel Space Observatory. The pure rotational transitions 0–0 S(1) and S(5) of H2, and the ground-state 110–101 …