Search Publications
Longitudinal Extent of 3He-rich Solar Energetic Particle Events Near 1 au
Kouloumvakos, Athanasios; Wimmer-Schweingruber, Robert F.; Allen, Robert C. +3 more
Multispacecraft observations of 3He-rich solar energetic particle (SEP) events are scarce, but much needed in order to understand and properly constrain the source and transport of these remarkably enriched 3He SEP events. In this paper, we report 15 3He-rich SEP events that were detected by the Advanced Compositio…
Rapid Dimming Followed by a State Transition: A Study of the Highly Variable Nuclear Transient AT 2019avd over 1000+ Days
Gandhi, Poshak; Miller, Jon M.; Ji, Long +16 more
The tidal disruption of a star around a supermassive black hole (SMBH) offers a unique opportunity to study accretion onto an SMBH on a human timescale. We present results from our 1000+ days monitoring campaign of AT 2019avd, a nuclear transient with tidal-disruption-event-like properties, with NICER, Swift, and Chandra. Our primary finding is th…
Comprehensive Analysis of a Filament-embedding Solar Active Region at Different Stages of Evolution
Li, Hui; Su, Yang; Li, Chuan +9 more
Active regions are the brightest structures seen in the solar corona, so their physical properties hold important clues to the physical mechanisms underlying coronal heating. In this work, we present a comprehensive study for a filament-embedding active region as determined from observations from multiple facilities including the Chinese Hα Solar …
Center-to-limb Variations in Solar Plage Using IRIS Observations
Young, Peter R.; Kayshap, Pradeep
The center-to-limb variations (CLV) of transition region line Gaussian fit parameters in solar plage are reported for the first time. The Si IV 1402.77 Å line observed by the Interface Region Imaging Spectrograph is used. The spectral intensity increases linearly from the disk center to the solar limb. Similarly, the nonthermal velocity also incre…
A Centiparsec-scale Compact Radio Core in the Nearby Galaxy M60
Yang, Jun; Liao, Mai; Dou, Liming +7 more
M60, an elliptical galaxy located 16.5 Mpc away, has an active nucleus with a very low luminosity and an extremely low accretion rate. Its central supermassive black hole (SMBH) has a mass of M BH ~ 4.5 × 109 M ⊙ and a Schwarzschild radius corresponding to R S ~ 5.4 µas. To investigate the nature o…
First Determination in the Extended Corona of the 2D Thermal Evolution of a Current Sheet after a Solar Eruption
Susino, Roberto; Fineschi, Silvano; Stangalini, Marco +26 more
For the first time the evolution of the coronal reconfiguration after a coronal mass ejection (CME) was observed by the multichannel Metis Coronagraph on board the ESA–Solar Orbiter mission. The images acquired in visible light (VL) between 3.0 and 5.4 R ⊙ show the formation after a CME of a bright elongated radial feature interpreted a…
AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations
Kaspi, Shai; Filippenko, Alexei V.; Barth, Aaron J. +39 more
We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the…
The VIRUS-dE Survey. I. Stars in Dwarf Elliptical Galaxies—3D Dynamics and Radially Resolved Stellar Initial Mass Functions
Bender, Ralf; Thomas, Jens; Hill, Gary J. +9 more
We analyze the stellar structure of a sample of dwarf ellipticals (dEs) inhabiting various environments within the Virgo cluster. Integral-field observations with a high spectral resolution allow us to robustly determine their low-velocity dispersions (∼25 km s‑1) and higher-order kinematic moments out to the half-light radius. We find …
Local Proton Heating at Magnetic Discontinuities in Alfvénic and Non-Alfvénic Solar Wind
Bandyopadhyay, R.; Tenerani, A.; Verniero, J. L. +1 more
We investigate the local proton energization at magnetic discontinuities/intermittent structures and the corresponding kinetic signatures in velocity phase space in Alfvénic (high cross helicity) and non-Alfvénic (low cross helicity) wind streams observed by Parker Solar Probe. By means of the partial variance of increments method, we find that th…
JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
Luhman, K. L.; Tremblin, P.; Parker, R. J. +4 more
We have used the multiobject mode of the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST) to obtain low-resolution 1–5 µm spectra of 22 brown dwarf candidates in the Orion Nebula Cluster, which were selected with archival images from the Hubble Space Telescope. One of the targets was previously classified a…