Search Publications
TESS Observations of Outbursts on Polars—Superflares
Qian, Shengbang; Wang, Qishan; Fang, Xiaohui
Flare events are magnetic activities on the stellar surface, which can provide us with information about the accretion behavior and evolution of polars. In this paper, we search for flare events on polars from all the available 2 minute cadence TESS data through visual inspection, and identify six flare events on five flaring stars from 185 polars…
Calcium Bright Knots and the Formation of Chromospheric Anemone Jets on the Sun
Shibata, Kazunari; Singh, Kunwar Alkendra Pratap; Nishida, Keisuke
Space-based observations show that the solar atmosphere from the solar chromosphere to the solar corona is filled with small-scale jets and is linked with small-scale explosions. These jets may be produced by mechanisms similar to those of large-scale flares and such jets may be related to the heating of the corona and chromosphere as well as the …
Has the Palomar 14 Globular Cluster Been Captured by the Milky Way?
Kroupa, Pavel; Haghi, Hosein; Zonoozi, Akram Hasani +1 more
We examine a new scenario to model the outer halo globular cluster (GC) Palomar 14 (Pal 14) over its lifetime by performing a comprehensive set of direct N-body calculations. We assume Pal 14 was born in a now detached/disrupted dwarf galaxy with a strong tidal field. Pal 14 evolved there until the slope of the stellar mass function (MF) became cl…
X-Ray and Spectral Ultraviolet Observations of Periodic Pulsations in a Solar Flare Fan/Looptop
Reeves, Katharine K.; Kazachenko, Maria D.; Lörinčík, Juraj +3 more
We present simultaneous X-ray and spectral ultraviolet observations of strikingly coherent oscillations in emission from a coronal looptop and fan structure, during the impulsive phase of a long-duration M-class solar flare. The ≈50 s oscillations are observed near in-phase by Solar Orbiter/STIX, GOES, and IRIS Fe XXI intensity, Doppler, and nonth…
Magnetic Helicity Signs and Flaring Propensity: Comparing the Force-free Parameter with the Helicity Signs of Hα Filaments and X-Ray Sigmoids
Martens, Petrus C.; Georgoulis, Manolis K.; Aparna, V.
Sigmoids produce strong eruptive events. Earlier studies have shown that the ICME axial magnetic field Bz can be predicted with some credibility by observing the corresponding filament or the polarity inversion line in the region of eruption and deriving the magnetic field direction from that. Sigmoids are coronal structures often associated with …
Discovering Subsolar Metallicity Brown Dwarf Candidates in the Small Magellanic Cloud
Pacifici, Camilla; Manjavacas, Elena; Sabbi, Elena +3 more
We present the discovery of the first rich population of brown dwarf candidates (cBD) at subsolar metallicity, observed by JWST outside the Milky Way (MW) in the young SMC star cluster NGC 602. Located in the Small Magellanic Cloud (SMC) "wing," in a very low-density environment (1.3 cm‑3) and at subsolar metallicity, NGC 602 is very yo…
Decay Timescales of Chromospheric Condensations in Solar Flare Footpoints
Kowalski, Adam F.; Butler, Elizabeth C.
Chromospheric condensations (CCs) are a prominent feature of flare footpoint heating in the solar flare standard model, yet their timescales and velocities are not well understood. Fisher derived several important analytical relationships, which have rarely been examined with modern spectral observations. The Interface Region Imaging Spectrograph …
Multispacecraft Energetic Particle Enhancements Associated with a Single Corotating Interaction Region
Desai, M. I.; Dayeh, M. A.; Elliott, H. A. +3 more
The radial evolution of particles accelerated at corotating interaction regions (CIRs) is not fully understood, particularly the distance range over which this particle acceleration occurs and how the energy spectra are modulated by transport through the inner heliosphere. Here, we present observations of energetic proton enhancements associated w…
Are There Local Dynamos Acting in Sunspot Regions?
Wang, Jingxiu; Jin, Chunlan; Ji, Haisheng +1 more
In solar physics, a long-unanswered question is whether or not there are local dynamos acting in sunspot regions. Here we report an observed pattern of magnetic evolution that makes the sunspots alive with ample complexity and energy. This anomalous pattern manifests as peculiar bipolar magnetic emergences (BMEs), exhibiting the following characte…
Cross-correlation of Luminous Red Galaxies with Machine Learning Selected Active Galactic Nuclei in HSC-SSP: Unobscured AGN Residing in More Massive Halos
Strauss, Michael A.; Greene, Jenny E.; Goulding, Andy D. +7 more
Active galactic nuclei (AGN) are the signposts of black hole growth, and likely play an important role in galaxy evolution. An outstanding question is whether AGN of different spectral types indicate different evolutionary stages in the coevolution of black holes and galaxies. We present the angular correlation function between an AGN sample selec…