Search Publications
Searching for Nuclear Obscuration in the Infrared Spectra of Nearby FR I Radio Galaxies
O'Dea, C. P.; Baum, S. A.; Gallimore, J. F. +2 more
How do active galactic nuclei with low optical luminosities produce powerful radio emission? Recent studies of active galactic nuclei with moderate radio and low optical luminosities (Fanaroff & Riley class I, FR I) searching for broad nuclear emission lines in polarized light, as predicted by some active galactic nucleus unification models, h…
2MASS J04435686+3723033 B: A Young Companion at the Substellar Boundary with Potential Membership in the β Pictoris Moving Group
Bowler, Brendan P.; Liu, Michael C.; Phillips, Caprice L. +2 more
We present a detailed characterization of 2MASS J04435750+3723031, a low-mass companion orbiting the young M2 star 2MASS J04435686+3723033 at 7"6 (550 au) with potential membership in the 23 Myr β Pictoris moving group (βPMG). Using near-infrared (NIR) spectroscopy of the companion from IRTF/SpeX, we have found a spectral type of M6 ± 1 and indica…
High-resolution Near-infrared Polarimetry and Submillimeter Imaging of FS Tau A: Possible Streamers in Misaligned Circumbinary Disk System
Henning, Thomas; Nakagawa, Takao; Terada, Hiroshi +56 more
We analyzed the young (2.8 Myr-old) binary system FS Tau A using near-infrared (H-band) high-contrast polarimetry data from Subaru/HiCIAO and submillimeter CO (J = 2-1) line emission data from Atacama Large Millimeter/submillimeter Array (ALMA). Both the near-infrared and submillimeter observations reveal several clear structures extending to ∼240…
Massive Stars in the SDSS-IV-APOGEE Survey: Wolf-Rayet Stars of the WN Type
Minniti, Dante; Hernández, Jesús; Roman-Lopes, Alexandre +3 more
In this paper, we describe the results obtained in our study of Galactic Wolf-Rayet stars of the WN type, using the APOGEE2 spectrographs. The APOGEE2 WN star near-infrared spectra presented here were selected through a careful examination of the APOGEE2 DR16 sample, being compound of at least one exemplar of each Wolf-Rayet star from WN4 to WN11 …
Flare Expansion to a Magnetic Rope Accompanied by Rare Radio Bursts
Dudík, Jaroslav; Kašparová, Jana; Zemanová, Alena +1 more
We present multispectral analysis (radio, Hα, ultraviolet (UV)/extreme ultraviolet (EUV), and hard X-ray) of a confined flare from 2015 March 12. This flare started within the active region NOAA 12 297 and then it expanded into a large preexisting magnetic rope embedded with a cold filament. The expansion started with several brightenings located …
Redshift Determinations from a Self-consistent Grid-based Lens Model for the Hubble Frontiers Field Cluster RXC J2248.7-4431 (AS1063)
Broadhurst, Tom; Coe, Dan; Lim, Jeremy +3 more
We present an iterative method to construct a freeform lens model that self-consistently reproduces the sky positions, geometrically inferred redshifts, and relative brightnesses of all multiply lensed images toward a galaxy cluster. This method is applied to the cluster RXC J2248.7-4431 (z = 0.348) from the Hubble Frontier Fields program, toward …
Using Stereoscopic Observations of Cometary Plasma Tails to Infer Solar Wind Speed
Wang, Yuming; Liu, Rui; Li, Xiaolei +2 more
Detection of the solar wind speed near the Sun is significant in understanding the heating and acceleration of the solar wind. Cometary plasma tails have long been used as natural probes for solar wind speed; previous solar wind speed estimates via plasma tails, however, were based on comet images from a single viewpoint, and the projection effect…
Interplanetary Magnetic Flux Rope Observed at Ground Level by HAWC
Alvarez, C.; Kieda, D.; Nieves-Chinchilla, T. +59 more
We report the ground-level detection of a Galactic cosmic-ray (GCR) flux enhancement lasting ∼17 hr and associated with the passage of a magnetic flux rope (MFR) over the Earth. The MFR was associated with a slow coronal mass ejection (CME) caused by the eruption of a filament on 2016 October 9. Due to the quiet conditions during the eruption and …
Follow-up Ground-based Observations of the Dwarf Nova KZ Gem
Thorstensen, John R.; Szkody, Paula; Dai, Zhibin +1 more
We present spectroscopy of stars in the immediate vicinity of the dwarf nova (DN) KZ Gem to confirm its identification, which is ambiguous in the literature. Analysis of 73 radial velocities spanning from 2014 to 2019 provides a high-precision orbital period of 0.2224628(2) days (∼5.34 hr) and shows KZ Gem to be a double-lined DN. Time series phot…
The Composition, Excitation, and Physical State of Atomic Gas in the Debris Disk Surrounding 51 Oph
Jenkins, Edward B.; Gry, Cécile
We measured 304 absorption features in the ultraviolet and visible spectra of the star 51 Oph, which is known to have a debris disk with a high inclination. We analyzed the relative populations of atoms in excited fine-structure and metastable levels that are maintained by optical pumping and collisional excitation by electrons, and we found that …