Search Publications
Uranium Abundances and Ages of r-process Enhanced Stars with Novel U II Lines
Beers, Timothy C.; Holmbeck, Erika M.; Hansen, Terese T. +7 more
The ages of the oldest stars shed light on the birth, chemical enrichment, and chemical evolution of the universe. Nucleocosmochronometry provides an avenue to determining the ages of these stars independent from stellar-evolution models. The uranium abundance, which can be determined for metal-poor r-process enhanced (RPE) stars, has been known t…
Exploring Stellar Cluster and Feedback-driven Star Formation in the Galactic Mid-infrared Bubble [HKS2019] E70
Pandey, Rakesh; Sharma, Saurabh; Dewangan, Lokesh +8 more
We present a comprehensive analysis of the Galactic mid-infrared bubble [HKS2019] E70 (E70) by adopting a multiwavelength approach to understand the physical environment and star formation scenario around it. We identified a small (radius ~1.7 pc) stellar cluster inside the E70 bubble, and its distance is estimated as 3.26 ± 0.45 kpc. This cluster…
Discovery and Timing of Millisecond Pulsars with the Arecibo 327 MHz Drift-scan Survey
Freire, Paulo C. C.; Deneva, Julia S.; McLaughlin, Maura A. +6 more
We present the discovery and timing solutions of four millisecond pulsars (MSPs) discovered in the Arecibo 327 MHz Drift-Scan Pulsar Survey. Three of these pulsars are in binary systems, consisting of a redback (PSR J2055+1545), a black widow (PSR J1630+3550), and a neutron star-white dwarf binary (PSR J2116+1345). The fourth MSP, PSR J2212+2450, …
High-resolution Chemical Abundances of the Nyx Stream
Ji, Alexander P.; Lisanti, Mariangela; Necib, Lina +5 more
Nyx is a nearby, prograde, and high-eccentricity stellar stream physically contained in the thick disk, but its origin is unknown. Nyx could be the remnant of a disrupted dwarf galaxy, in which case the associated dark matter substructure could affect terrestrial dark matter direct-detection experiments. Alternatively, Nyx could be a signature of …
The Structure of Coronal Mass Ejections Recorded by the K-Coronagraph at Mauna Loa Solar Observatory
Chen, Yao; Xia, Lidong; Li, Leping +3 more
Previous survey studies reported that coronal mass ejections (CMEs) can exhibit various structures in white-light coronagraphs, and ~30% of them have the typical three-part feature in the high corona (e.g., 2-6 R ⊙), which has been taken as the prototypical structure of CMEs. It is widely accepted that CMEs result from eruption of magne…
The Ultraviolet to Mid-infrared Extinction Law of the Taurus Molecular Cloud Based on the Gaia DR3, GALEX, APASS, Pan-STARRS1, 2MASS, and WISE Surveys
Wang, Shu; Chen, Xiaodian; Li, Ling +1 more
Interstellar-dust extinction law is essential for interpreting observations. In this work, we investigate the ultraviolet (UV)-mid-infrared (IR) extinction law of the Taurus molecular cloud and its possible variations. We select 504,988 dwarf stars (4200 K ≤ T eff ≤ 8000 K) and 4757 giant stars (4200 K ≤ T eff ≤ 5200 K) based…
Solar Orbiter and SDO Observations, and a Bifrost Magnetohydrodynamic Simulation of Small-scale Coronal Jets
Tiwari, Sanjiv K.; Cheung, Mark C. M.; Berghmans, David +3 more
We report high-resolution, high-cadence observations of five small-scale coronal jets in an on-disk quiet Sun region observed with Solar Orbiter's EUI/HRIEUV in 174 Å. We combine the HRIEUV images with the EUV images of SDO/AIA and investigate the magnetic setting of the jets using coaligned line-of-sight magnetograms from SD…
PEARLS: JWST Counterparts of Microjansky Radio Sources in the Time Domain Field
Grogin, Norman A.; Koekemoer, Anton M.; Pirzkal, Nor +38 more
The Time Domain Field (TDF) near the North Ecliptic Pole in JWST's continuous-viewing zone will become a premier "blank field" for extragalactic science. JWST/NIRCam data in a 16 arcmin2 portion of the TDF identify 4.4 µm counterparts for 62 of 63 3 GHz sources with S(3 GHz) > 5 µJy. The one unidentified radio source may …
New Insights in the Bubble Wall of NGC 3324: Intertwined Substructures and a Bipolar Morphology Uncovered by JWST
Dewangan, L. K.; Sharma, Saurabh; Mayya, Y. D. +4 more
We report the discovery of intertwined/entangled substructures toward the bubble wall of NGC 3324 below a physical scale of 4500 au, which is the sharp edge/ionization front/elongated structure traced at the interface between the H II region and the molecular cloud. The sharp edge appears wavy in the Spitzer 3.6-8.0 µm images (resolution ~2″…
Search for X-Ray Quasiperiodicity of Six AGNs Using the Gaussian Process Method
Zhang, Haoyang; Yang, Shenbang; Dai, Benzhong
The quasiperiodic oscillations (QPOs) found in active galactic nuclei (AGNs) are a very interesting observational phenomenon implying an unknown physical mechanism around supermassive black holes. Several AGNs have been found to have QPO phenomena in the X-ray energy band. Long-duration X-ray observations were collected and reduced for six AGNs wi…