Search Publications
Effects of Grain Alignment with Magnetic Fields on Grain Growth and the Structure of Dust Aggregates
Hoang, Thiem
Dust grains drift through the interstellar medium and are aligned with the magnetic field. Here we study the effect of grain alignment and motion on grain growth in molecular clouds (MCs). We first discuss the characteristic timescales of alignment of the grain axis of maximum inertia ( $\hat{{\boldsymbol{a}}}$ 1) with its angular momen…
CLEAR: Paschen-β Star Formation Rates and Dust Attenuation of Low-redshift Galaxies
Papovich, Casey; Finkelstein, Steven L.; Cleri, Nikko J. +12 more
We use Paschen-β (Paβ; 1282 nm) observations from the Hubble Space Telescope G141 grism to study the star formation and dust-attenuation properties of a sample of 29 low-redshift (z < 0.287) galaxies in the CANDELS Lyα Emission at Reionization survey. We first compare the nebular attenuation from Paβ/Hα with the stellar attenuation inferred fro…
Classifying Unidentified X-Ray Sources in the Chandra Source Catalog Using a Multiwavelength Machine-learning Approach
Kargaltsev, Oleg; Chen, Steven; Yang, Hui +3 more
The rapid increase in serendipitous X-ray source detections requires the development of novel approaches to efficiently explore the nature of X-ray sources. If even a fraction of these sources could be reliably classified, it would enable population studies for various astrophysical source types on a much larger scale than currently possible. Clas…
Homologous Accelerated Electron Beams, a Quasiperiodic Fast-propagating Wave, and a Coronal Mass Ejection Observed in One Fan-spine Jet
Shen, Yuandeng; Zhou, Chengrui; Zhou, Xinping +3 more
Using imaging and radio multi-wavelength observations, we studied the origin of two homologous accelerated electron beams and a quasiperiodic fast-propagating (QFP) wave train associated with a solar jet on 2012 July 14. The jet occurred in a small-scale fan-spine magnetic system embedded in a large-scale pseudostreamer associated with a GOES C1.4…
MAGAZ3NE: High Stellar Velocity Dispersions for Ultramassive Quiescent Galaxies at z ≳ 3
Cooper, M. C.; Urbano Stawinski, Stephanie M.; Muzzin, Adam +17 more
In this work, we publish stellar velocity dispersions, sizes, and dynamical masses for eight ultramassive galaxies (UMGs; $\mathrm{log}({M}_{* }/{M}_{\odot })$ > 11), z ≳ 3) from the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) Survey, more than doubling the number of such galaxies with velocity dispersion measurements at this …
New Coronae and Stellar Associations Revealed by a Clustering Analysis of the Solar Neighborhood
Faherty, Jacqueline K.; Gagné, Jonathan; Moranta, Leslie +1 more
We present the results of a density-based clustering analysis of the 6D XYZ Galactic positions and UVW-space velocities of nearby (≤200 pc) Gaia Early Data Release 3 stars with radial velocities using HDBSCAN, in opposition to previous studies (Kounkel & Covey 2019; Meingast et al. 2021) that only included positions and tangential velocities. …
WO-type Wolf-Rayet Stars: The Last Hurrah of Massive Star Evolution
Aadland, Erin; Massey, Philip; Hillier, D. John +3 more
Are WO-type Wolf-Rayet (WR) stars in the final stage of massive star evolution before core-collapse? Although WC- and WO-type WRs have very similar spectra, WOs show a much stronger O VI λλ3811,34 emission-line feature. This has usually been interpreted to mean that WOs are more oxygen rich than WCs, and thus further evolved. However, previous stu…
Constraining the Physical Properties of Stellar Coronal Mass Ejections with Coronal Dimming: Application to Far-ultraviolet Data of ϵ Eridani
Loyd, R. O. Parke; France, Kevin; Youngblood, Allison +9 more
Coronal mass ejections (CMEs) are a prominent contributor to solar system space weather and might have impacted the Sun's early angular momentum evolution. A signal diagnostic of CMEs on the Sun is coronal dimming: a drop in coronal emission, tied to the mass of the CME, that is the direct result of removing emitting plasma from the corona. We pre…
A New Method for Direct Measurement of Isotopologue Ratios in Protoplanetary Disks: A Case Study of the 12CO/13CO Ratio in the TW Hya Disk
Nomura, Hideko; Tsukagoshi, Takashi; Furuya, Kenji +2 more
Planetary systems are thought to be born in protoplanetary disks. Isotope ratios are a powerful tool for investigating the material origin and evolution from molecular clouds to planetary systems via protoplanetary disks. However, it is challenging to measure the isotope (isotopologue) ratios, especially in protoplanetary disks, because the emissi…
The First Near-infrared Transmission Spectrum of HIP 41378 f, A Low-mass Temperate Jovian World in a Multiplanet System
Kirk, James; López-Morales, Mercedes; Alam, Munazza K. +22 more
We present a near-infrared transmission spectrum of the long-period (P = 542 days), temperate (T eq = 294 K) giant planet HIP 41378 f obtained with the Wide-Field Camera 3 instrument aboard the Hubble Space Telescope (HST). With a measured mass of 12 ± 3 M ⊕ and a radius of 9.2 ± 0.1 R ⊕, HIP 41378 f has an extreme…