Search Publications
Deuterated Polycyclic Aromatic Hydrocarbons in the Interstellar Medium: The Aliphatic C-D Band Strengths
Li, Aigen; Yang, X. J.
Deuterium (D) was exclusively generated in the Big Bang, and the standard Big Bang nucleosynthesis (BBN) model predicts a primordial abundance of D/H ≈ 26 parts per million (ppm). As the Galaxy evolves, D/H gradually decreases because of astration. The Galactic chemical evolution (GCE) model predicts a present-day abundance of D/H ≳ 20 ppm. Howeve…
Survey for Distant Stellar Aggregates in the Galactic Disk: Detecting 2000 Star Clusters and Candidates, along with the Dwarf Galaxy IC 10
Luo, Yangping; Wang, Kun; Liu, Xiaochen +5 more
Despite having data for over 109 stars from Gaia, less than 104 star clusters and candidates have been discovered. In particular, distant star clusters are rarely identified, due to the challenges posed by heavy extinction and great distance. However, Gaia data has continued to improve, enabling even fainter cluster members t…
Atomic Transition Probabilities for Transitions of Si I and Si II and the Silicon Abundances of Several Very Metal-poor Stars
Sneden, C.; Roederer, I. U.; Lawler, J. E. +2 more
We report new measurements of branching fractions for 20 UV and blue lines in the spectrum of neutral silicon (Si I) originating in the 3s 23p4s 3Po 1,2,1Po 1, and 3s3p 3 1Do 1,2 upper levels. Transitions studied include both st…
A Data-driven, Physics-based Transport Model of Solar Energetic Particles Accelerated by Coronal Mass Ejection Shocks Propagating through the Solar Coronal and Heliospheric Magnetic Fields
Riley, Pete; Zhang, Ming; Lario, David +5 more
In an effort to develop computational tools for predicting radiation hazards from solar energetic particles (SEPs), we have created a data-driven physics-based particle transport model to calculate the injection, acceleration, and propagation of SEPs from coronal mass ejection (CME) shocks traversing through the solar corona and interplanetary mag…
Time-variable Jet Ejections from RW Aur A, RY Tau, and DG Tau
Ohyama, Youichi; Pyo, Tae-Soo; Liu, Chun-Fan +17 more
We present Gemini-NIFS, Very Large Telescope-SINFONI, and Keck-OSIRIS observations of near-IR [Fe II] emission that are associated with well-studied jets from three active T Tauri stars-RW Aur A, RY Tau, and DG Tau-taken from 2012 to 2021. We primarily cover the redshifted jet from RW Aur A and the blueshifted jets from RY Tau and DG Tau, in order…
The Lyα Reference Sample. XIV. Lyα Imaging of 45 Low-redshift Star-forming Galaxies and Inferences on Global Emission
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +18 more
We present Lyα imaging of 45 low-redshift star-forming galaxies observed with the Hubble Space Telescope. The galaxies have been selected to have moderate to high star formation rates (SFRs) using far-ultraviolet (FUV) luminosity and Hα equivalent width criteria, but no constraints on Lyα luminosity. We employ a pixel stellar continuum fitting cod…
Magellan/M2FS and MMT/Hectochelle Spectroscopy of Dwarf Galaxies and Faint Star Clusters within the Galactic Halo
Caldwell, Nelson; Mateo, Mario; Roederer, Ian U. +5 more
We present spectroscopic data for 16,369 stellar targets within and/or toward 38 dwarf spheroidal galaxies and faint star clusters within the Milky Way halo environment. All spectra come from observations with the multiobject, fiber-fed echelle spectrographs M2FS at the Magellan/Clay telescope or Hectochelle at the MMT, reaching a typical limiting…
Aliphatics and Aromatics in the Universe: The Pre-JWST Era
Li, Aigen; Yang, X. J.
The so-called "unidentified infrared emission" (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 µm ubiquitously seen in a wide variety of astrophysical regions are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. Astronomical PAHs often have an aliphatic component (e.g., aliphatic sidegroups like methyl -CH3 …
On the General Correlation between 3D Solar Wind Speed and Density Model and Solar Proxies
Bzowski, M.; Tokumaru, M.; Porowski, C.
The solar wind (SW) is a supersonic outflow of plasma from the solar corona, with the latitudinal speed and density profiles varying with the solar activity. The SW protons charge exchange with the inflowing interstellar neutral atoms and create energetic neutral atoms (ENAs), which bring information on the physical state of the plasma within the …
Discovery and Timing of Millisecond Pulsars in the Globular Cluster M5 with FAST and Arecibo
Fu, Xiaoting; Tsai, Chao-Wei; Cadelano, Mario +29 more
We report on a comprehensive multiwavelength study of the pulsars in the globular cluster (GC) M5, including the discovery of M5G, a new compact noneclipsing "black widow" pulsar. Thanks to the analysis of 34 yr of radio data taken with the Five-hundred-meter Aperture Spherical radio Telescope and Arecibo telescopes, we obtained new phase-connecte…