Search Publications
Solar Electron Beam-Langmuir Wave Interactions and How They Modify Solar Electron Beam Spectra: Solar Orbiter Observations of a Match Made in the Heliosphere
Verscharen, Daniel; Maksimovic, Milan; Ryan, Daniel F. +7 more
Solar Orbiter's four in situ instruments have recorded numerous energetic electron events at heliocentric distances between 0.5 and 1 au. We analyze energetic electron fluxes, spectra, pitch-angle distributions, associated Langmuir waves, and type III solar radio bursts for three events to understand what causes modifications in the electron flux …
Are "Changing-look" Active Galactic Nuclei Special in the Coevolution of Supermassive Black Holes and Their Hosts? I.
Filippenko, A. V.; Wang, J.; Gao, C. +5 more
The nature of the so-called "changing-look" (CL) active galactic nucleus (AGN), which is characterized by spectral-type transitions within ~10 yr, remains an open question. As the first in our series of studies, we attempt here to understand the CL phenomenon from the view of the coevolution of AGNs and their host galaxies (i.e., if CL-AGNs are at…
The Isotropic Center of NGC 5419-A Core in Formation?
Bender, Ralf; Thomas, Jens; Naab, Thorsten +5 more
With its cored surface brightness profile, the elliptical galaxy NGC 5419 appears as a typical high-mass early-type galaxy (ETG). However, the galaxy hosts two distinct nuclei in its center. We use high-signal MUSE (Multi-unit Spectroscopic Explorer (Based on observations collected at the European Organisation for Astronomical Research in the Sout…
Time Dependence of 50-250 MeV Galactic Cosmic-Ray Protons between Solar Cycles 24 and 25, Measured by the High-energy Particle Detector on board the CSES-01 Satellite
Vitale, V.; Ubertini, P.; Potgieter, M. S. +54 more
Time-dependent energy spectra of galactic cosmic rays (GCRs) carry crucial information regarding their origin and propagation throughout the interstellar environment. When observed at the Earth, after traversing the interplanetary medium, such spectra are heavily affected by the solar wind and the embedded solar magnetic field permeating the inner…
NEID Reveals That the Young Warm Neptune TOI-2076 b Has a Low Obliquity
Mahadevan, Suvrath; Wisniewski, John; Wright, Jason T. +27 more
TOI-2076 b is a sub-Neptune-sized planet (R = 2.39 ± 0.10 R ⊕) that transits a young (204 ± 50 MYr) bright (V = 9.2) K-dwarf hosting a system of three transiting planets. Using spectroscopic observations obtained with the NEID spectrograph on the WIYN 3.5 m Telescope, we model the Rossiter-McLaughlin effect of TOI-2076 b, and derive a s…
Resolved Velocity Profiles of Galactic Winds at Cosmic Noon
Kacprzak, Glenn G.; Glazebrook, Karl; Tran, Kim-Vy H. +7 more
We study the kinematics of the interstellar medium (ISM) viewed "down the barrel" in 20 gravitationally lensed galaxies during cosmic noon (z = 1.5-3.5). We use moderate-resolution spectra (R ~ 4000) from Keck's Echellette Spectrograph and Imager and Magellan/MagE to spectrally resolve the ISM absorption in these galaxies into ~10 independent elem…
Identification of a Helium Donor Star in NGC 247 ULX-1
Feng, Hua; Bian, Fuyan; Zhou, Changxing
With Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations, we detected highly variable helium emission lines from the optical counterpart of the supersoft ultraluminous X-ray source (ULX) NGC 247 ULX-1. No Balmer lines can be seen in the source spectrum. This is the first evidence for the presence of a helium donor star in UL…
Detection of Dust in High-velocity Cloud Complex C-Enriched Gas Accreting onto the Milky Way
Richter, Philipp; Kriss, Gerard A.; Fox, Andrew J. +4 more
We present the detection of dust depletion in Complex C, a massive, infalling, low-metallicity high-velocity cloud in the northern Galactic hemisphere that traces the ongoing accretion of gas onto the Milky Way. We analyze a very high signal-to-noise Hubble Space Telescope Cosmic Origins Spectrograph spectrum of active galactic nucleus (AGN) Mrk 8…
Probing the Galactic Diffuse Continuum Emission with COSI
Boggs, Steven E.; Tomsick, John A.; Siegert, Thomas +10 more
In 2016, the Compton Spectrometer and Imager (COSI) had a successful 46 day flight on board NASA's Super Pressure Balloon platform. In this work, we report measurements of the Galactic diffuse continuum emission (GDCE) observed toward the inner Galaxy during the flight, which in the COSI energy band (0.2-5 MeV) is primarily generated from inverse …
Geometry and Kinematics of a Dancing Milky Way: Unveiling the Precession and Inclination Variation across the Galactic Plane via Open Clusters
He, Zhihong
This Letter presents a study of the geometry and motion of the Galactic disk using open clusters in the Gaia era. The findings suggest that the inclination θ i of the Galactic disk increases gradually from the inner to the outer disk, with a shift in orientation at the Galactocentric radius of approximately 6 ± 1 kpc. Furthermore, thi…