Search Publications
PIC Simulations of Microinstabilities and Waves at Near-Sun Solar Wind Perpendicular Shocks: Predictions for Parker Solar Probe and Solar Orbiter
Yang, Zhongwei; Liu, Ying D.; Guo, Fan +6 more
Microinstabilities and waves excited at moderate-Mach-number perpendicular shocks in the near-Sun solar wind are investigated by full particle-in-cell simulations. By analyzing the dispersion relation of fluctuating field components directly issued from the shock simulation, we obtain key findings concerning wave excitations at the shock front: (1…
The Broad-lined Ic Supernova ZTF18aaqjovh (SN 2018bvw): An Optically Discovered Engine-driven Supernova Candidate with Luminous Radio Emission
Kulkarni, S. R.; Cenko, S. Bradley; Riddle, Reed +25 more
We present ZTF18aaqjovh (SN 2018bvw), a high-velocity ("broad-lined") stripped-envelope (Type Ic) supernova (Ic-BL SN) discovered in the Zwicky Transient Facility one-day cadence survey. ZTF18aaqjovh shares a number of features in common with engine-driven explosions: the photospheric velocity and the shape of the optical light curve are very simi…
Investigating the Chromospheric Footpoints of the Solar Wind
De Pontieu, Bart; McIntosh, Scott W.; Brooks, David H. +1 more
Coronal holes present the source of the fast solar wind. However, the fast solar wind is not unimodal—there are discrete, but subtle, compositional, velocity, and density structures that differentiate different coronal holes as well as wind streams that originate within one coronal hole. In this Letter we exploit full-disk observational "mosaics" …
The Hα Emission Line Variations of HR 6819
Gies, Douglas R.; Wang, Luqian
The star system HR 6819 was recently proposed by Rivinius et al. as the site of the nearest example of a stellar-mass black hole. Their spectra show evidence of two components: a B3 III star in a 40 day orbit and a stationary B-emission line star. Based upon the orbital mass function and the lack of evidence of a spectral component with reflex orb…
Tracing the Coevolution Path of Supermassive Black Holes and Spheroids with AKARI-selected Ultraluminous IR Galaxies at Intermediate Redshifts
Yamamura, Issei; Toba, Yoshiki; Noda, Hirofumi +6 more
We present the stellar population and ionized-gas outflow properties of ultraluminous IR galaxies (ULIRGs) at z = 0.1-1.0 that are selected from the AKARI far-IR all-sky survey. We construct a catalog of 1077 ULIRGs to examine feedback effects after major mergers. Of the 1077 ULIRGs, 202 are spectroscopically identified by SDSS and Subaru/FOCAS ob…
Spectroscopic Detection of the Pre-White Dwarf Companion of Regulus
Gies, Douglas R.; Lester, Kathryn V.; Wang, Luqian +6 more
Mass transfer in an interacting binary will often strip the mass donor of its entire envelope and spin up the mass gainer to near critical rotation. The nearby B-type star Regulus represents a binary in the post-mass transfer stage: it is a rapid rotator with a very faint companion in a 40 days orbit. Here we present the results of a search for th…
Hydroxylated Mg-rich Amorphous Silicates: A New Component of the 3.2 µm Absorption Band of Comet 67P/Churyumov-Gerasimenko
Carlson, R. W.; Kappel, D.; Pommerol, A. +13 more
The VIRTIS imaging spectrometer on board Rosetta has shown that the nucleus surface of comet 67P/Churyumov-Gerasimenko (67P/CG) is characterized by a broad absorption band at around 3.2 µm. The feature is ubiquitous across the surface and its attribution to (a) specific material(s) has been challenging. In the present Letter, we report an ex…
Neon Abundances of B Stars in the Solar Neighborhood
Zhao, Gang; Alexeeva, Sofya; Sadakane, Kozo +4 more
We constructed a comprehensive model atom for Ne I-Ne II using the most-up-to-date atomic data available and evaluated the nonlocal thermodynamic equilibrium (NLTE) line formation for Ne I and Ne II in classical 1D models representing the atmospheres of B-type stars. We find that the large NLTE strengthening of the Ne I lines corresponding to the …
Hi-C 2.1 Observations of Small-scale Miniature-filament-eruption-like Cool Ejections in an Active Region Plage
Winebarger, Amy R.; Panesar, Navdeep K.; Moore, Ronald L. +5 more
We examine 172 Å ultra-high-resolution images of a solar plage region from the High-Resolution Coronal Imager, version 2.1 (Hi-C 2.1, or Hi-C) rocket flight of 2018 May 29. Over its five minute flight, Hi-C resolved a plethora of small-scale dynamic features that appear near noise level in concurrent Solar Dynamics Observatory (SDO) Atmospheric Im…
A Study of the Observational Properties of Coronal Mass Ejection Flux Ropes near the Sun
Gopalswamy, N.; Sindhuja, G.
We present the observational properties of coronal mass ejection (CME) flux ropes (FRs) near the Sun based on a set of 35 events from solar cycle 24 (2010-2017). We derived the CME FR properties using the Flux Rope from Eruption Data technique. According to this technique, the geometrical properties are obtained from a flux-rope fit to CMEs and th…