Search Publications
The Fluid-like and Kinetic Behavior of Kinetic Alfvén Turbulence in Space Plasma
Verscharen, Daniel; Wicks, Robert T.; Chen, Christopher H. K. +3 more
Kinetic Alfvén waves (KAWs) are the short-wavelength extension of the magnetohydrodynamics Alfvén-wave branch in the case of highly oblique propagation with respect to the background magnetic field. Observations of space plasma show that small-scale turbulence is mainly KAW-like. We apply two theoretical approaches, a collisional two-fluid theory …
Impulsive Coronal Heating from Large-scale Magnetic Rearrangements: From IRIS to SDO/AIA
Testa, Paola; Petralia, Antonino; Reale, Fabio +1 more
The Interface Region Imaging Spectrograph (IRIS) has observed bright spots at the transition region footpoints associated with heating in the overlying loops, as observed by coronal imagers. Some of these brightenings show significant blueshifts in the Si IV line at 1402.77 Å ({log}T[{{K}}]≈ 4.9). Such blueshifts cannot be reproduced by coronal lo…
The Tail of PSR J0002+6216 and the Supernova Remnant CTB 1
Frail, D. A.; Kerr, M.; Schinzel, F. K. +2 more
We have carried out Very Large Array imaging and a Fermi timing analysis of the 115 ms γ-ray and radio pulsar PSR J0002+6216. We found that the pulsar lies at the apex of a narrowly collimated cometary-like 7‧ tail of nonthermal radio emission, which we identify as a bow-shock pulsar wind nebula. The tail of the nebula points back toward the geome…
On the Origin of the Magnetic Energy in the Quiet Solar Chromosphere
Martínez-Sykora, Juan; De Pontieu, Bart; Carlsson, Mats +3 more
The presence of magnetic field is crucial in the transport of energy through the solar atmosphere. Recent ground-based and space-borne observations of the quiet Sun have revealed that magnetic field accumulates at photospheric heights, via a local dynamo or from small-scale flux emergence events. However, most of this small-scale magnetic field ma…
The Birth of a Jet-driven Twin CME and Its Deflection from Remote Magnetic Fields
Shen, Yuandeng; Duan, Yadan; Chen, Hechao +1 more
We report the formation of a complicated coronal mass ejection (CME) on 2015 August 23 by using the high temporal and high spatial resolution multi-wavelength observations taken by the Solar Dynamic Observatory and the Solar and Heliospheric Observatory. The CME exhibited both jetlike and bubble-like components simultaneously, and therefore, we ca…
Evidence for a Young Stellar Population in Nearby Type 1 Active Galaxies
Ho, Luis C.; Kim, Minjin
To understand the physical origin of the close connection between supermassive black holes (BHs) and their host galaxies, it is vital to investigate star formation properties in active galaxies. Using a large data set of nearby type 1 active galactic nuclei (AGNs) with detailed structural decomposition based on high-resolution optical images obtai…
A Search for Gravitationally Lensed Gamma-Ray Bursts in the Data of the Interplanetary Network and Konus-Wind
Zhang, X.; Hurley, K.; von Kienlin, A. +19 more
We examine a sample of 2301 gamma-ray bursts, detected by Konus-Wind in the triggered mode between 1994 and 2017 and localized by the interplanetary network (IPN), for evidence of gravitational lensing. We utilize all the available gamma-ray burst (GRB) data: time histories, localizations, and energy spectra. We employ common IPN techniques to fin…
The Masses of Supernova Remnant Progenitors in M83
Williams, Benjamin F.; Blair, William P.; Dolphin, Andrew +5 more
We determine the ages of the young, resolved stellar populations at the locations of 237 optically identified supernova remnants in M83. These age distributions put constraints on the progenitor masses of the supernovae that produced 199 of the remnants. The other 38 show no evidence for having a young progenitor and are therefore good Type Ia SNR…
Large-scale Magnetic Funnels in the Solar Corona
Velli, Marco; Panasenco, Olga; Panasenco, Aram
We describe open coronal magnetic fields with a specific geometry—large-scale coronal magnetic funnels—that are found to play an important role in coronal dynamics. Coronal magnetic funnels can be attributed to three main factors: (i) the presence of pseudostreamer(s), (ii) the presence of filament channels, and (iii) the presence of active region…
Spectral Energy Distribution of Blue Stragglers in the Core of 47 Tucanae
Anderson, Jay; Pallanca, Cristina; Dalessandro, Emanuele +7 more
We have constructed the spectral energy distributions (SEDs) of a sample of blue straggler stars (BSSs) in the core of the globular cluster 47 Tucanae, taking advantage of the large set of high resolution images, ranging from the ultraviolet to the near-infrared, obtained with the Advanced Camera for Surveys/High Resolution Channel of the Hubble S…