Search Publications
Unusual Abundances from Planetary System Material Polluting the White Dwarf G238-44
Koester, D.; Zuckerman, B.; Jura, M. +3 more
Ultraviolet and optical spectra of the hydrogen-dominated atmosphere white dwarf star G238-44 obtained with FUSE, Keck/HIRES, HST/COS, and HST/STIS reveal 10 elements heavier than helium: C, N, O, Mg, Al, Si, P, S, Ca, and Fe. G238-44 is only the third white dwarf with nitrogen detected in its atmosphere from polluting planetary system material. K…
Black Hole Mass Measurements of Early-type Galaxies NGC 1380 and NGC 6861 through ALMA and HST Observations and Gas-dynamical Modeling
Ho, Luis C.; Barth, Aaron J.; Buote, David A. +6 more
We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 observations of CO(2-1) emission from the circumnuclear disks in two early-type galaxies, NGC 1380 and NGC 6861. The disk in each galaxy is highly inclined (i ~ 75°), and the projected velocities of the molecular gas near the galaxy centers are ~300 km s-1 in NGC 138…
Possible Systematic Rotation in the Mature Stellar Population of a z = 9.1 Galaxy
Inoue, Akio K.; Hashimoto, Takuya; Sugahara, Yuma +13 more
We present new observations with the Atacama Large Millimeter/submillimeter Array for a gravitationally lensed galaxy at z = 9.1, MACS1149-JD1. [O III] 88 µm emission is detected at 10σ with a spatial resolution of ~0.3 kpc in the source plane, enabling the most distant morphokinematic study of a galaxy. The [O III] emission is distributed s…
Modeling of Joint Parker Solar Probe-Metis/Solar Orbiter Observations
Zank, G. P.; Zhao, L. -L.; Telloni, D. +1 more
We present the first theoretical modeling of joint Parker Solar Probe (PSP)-Metis/Solar Orbiter (SolO) quadrature observations. The combined observations describe the evolution of a slow solar wind plasma parcel from the extended solar corona (3.5-6.3 R ⊙) to the very inner heliosphere (23.2 R ⊙). The Metis/SolO instrument re…
Radio Detection of an Elusive Millisecond Pulsar in the Globular Cluster NGC 6397
Fu, Xiaoting; Tsai, Chao-Wei; Freire, Paulo C. C. +32 more
We report the discovery of a new 5.78 ms period millisecond pulsar (MSP), PSR J1740-5340B (NGC 6397B), in an eclipsing binary system discovered with the Parkes radio telescope (now also known as Murriyang) in Australia and confirmed with the MeerKAT radio telescope in South Africa. The measured orbital period, 1.97 days, is the longest among all e…
Tracing Accretion onto Herbig Ae/Be Stars Using the Brγ Line
Calvet, Nuria; Espaillat, Catherine C.; Grant, Sierra L. +2 more
Accretion plays an important role in protoplanetary disk evolution, and it is thought that the accretion mechanism changes between low- and high-mass stars. Here we characterize accretion in intermediate-mass, pre-main-sequence Herbig Ae/Be (HAeBe) stars to search for correlations between accretion and system properties. We present new high-resolu…
An Old, Metal-rich Accreted Stellar Component in the Milky Way Stellar Disk
Feuillet, Diane K.; Feltzing, Sofia; Bensby, Thomas +1 more
We study the possibility that the Milky Ways' cool stellar disk includes mergers with ancient stars. Galaxies are understood to form in a hierarchical manner, where smaller (proto-)galaxies merge into larger ones. Stars in galaxies, like the Milky Way, contain in their motions and elemental abundance tracers of past events and can be used to disen…
Geminga SNR: Possible Candidate of the Local Cosmic-Ray Factory
Yuan, Qiang; Liu, Wei; Bi, Xiao-Jun +5 more
The precise measurements of energy spectra and anisotropy could help us uncover the local cosmic-ray accelerators. Our recent works have shown that spectral hardening above 200 GeV in the energy spectra and transition of large-scale anisotropy at ~100 TeV are of local source origin. Less than 100 TeV, both spectral hardening and anisotropy explici…
Charge State Calculation for Global Solar Wind Modeling
Landi, E.; van der Holst, B.; Szente, J.
The charge state composition of the solar wind carries information about the electron temperature, density, and velocity of plasma in the solar corona that cannot always be measured with remote sensing techniques, due to limitations in instrumental sensitivity and field of view as well as line-of-sight integration issues. However, in situ measurem…
Testing the Limits of AGN Feedback and the Onset of Thermal Instability in the Most Rapidly Star-forming Brightest Cluster Galaxies
McNamara, Brian R.; Donahue, Megan; Voit, G. Mark +8 more
We present new, deep, narrow- and broadband Hubble Space Telescope observations of seven of the most star-forming brightest cluster galaxies (BCGs). Continuum-subtracted [OII] maps reveal the detailed, complex structure of warm (T ~ 104 K) ionized gas filaments in these BCGs, allowing us to measure spatially resolved star formation rate…