Search Publications
Flexible Models for Galaxy Star Formation Histories Both Shift and Scramble the Optical Color-Mass-to-light Ratio (M/L) Relationship
Leja, Joel; Li, Yijia
The remarkably tight relationship between galaxy optical color and stellar mass-to-light ratio (M */L) is widely used for efficient stellar mass estimates. However, it remains unclear whether this low scatter comes from a natural order in the galaxy population, or whether it is driven by simple relationships in the models used to descri…
Twin Extreme Ultraviolet Waves in the Solar Corona
Zhang, Liang; Chen, Yao; Zheng, Ruisheng +2 more
Solar extreme ultraviolet (EUV) waves are spectacular propagating disturbances with EUV enhancements in annular shapes in the solar corona. These EUV waves carry critical information about the coronal magnetized plasma that can shed light on the elusive physical parameters (e.g., the magnetic field strength) by global solar coronal magnetoseismolo…
A Spatially Resolved Study of Hard X-Ray Emission in Kepler's Supernova Remnant: Indications of Different Regimes of Particle Acceleration
Katsuda, Satoru; Terada, Yukikatsu; Miceli, Marco +6 more
Synchrotron X-ray emission in young supernova remnants (SNRs) is a powerful diagnostic tool to study the population of high-energy electrons accelerated at the shock front and the acceleration process. We performed a spatially resolved spectral analysis of NuSTAR and XMM-Newton observations of the young Kepler's SNR, aiming to study in detail its …
Finite-resolution Deconvolution of Multiwavelength Imaging of 20,000 Galaxies in the COSMOS Field: The Evolution of Clumpy Galaxies over Cosmic Time
Muzzin, Adam; Marchesini, Danilo; Stefanon, Mauro +5 more
Compact star-forming clumps observed in distant galaxies are often suggested to play a crucial role in galaxy assembly. In this paper, we use a novel approach of applying finite-resolution deconvolution on ground-based images of the COSMOS field to resolve 20,185 star-forming galaxies (SFGs) at 0.5 < z < 2 to an angular resolution of 0.″3 an…
A Monte Carlo Method for Evaluating Empirical Gyrochronology Models and Its Application to Wide Binary Benchmarks
Buzasi, Derek; Oswalt, T. D.; von Hippel, Ted +3 more
Accurate stellar ages are essential for our understanding of the star formation history of the Milky Way and Galactic chemical evolution, as well as to constrain exoplanet formation models. Gyrochronology, a relationship between stellar rotation and age, appears to offer a reliable age indicator for main-sequence (MS) stars over the mass range of …
The Role of Binarity and Stellar Rotation in the Split Main Sequence of NGC 2422
de Grijs, Richard; Li, Chengyuan; Chen, Li +8 more
In addition to the extended main-sequence turnoffs widely found in young and intermediate-age (~600 Myr to 2 Gyr old) star clusters, some younger clusters even exhibit split main sequences (MSs). Different stellar rotation rates are proposed to account for the bifurcated MS pattern, with red and blue MSs (rMS and bMS) populated by fast and slowly …
Non-LTE Inversion of Prominence Spectroscopic Observations in Hα and Mg II h&k lines
Heinzel, Petr; Schmieder, Brigitte; Jejčič, Sonja +4 more
We continued our investigation of the plasma characteristics of a quiescent prominence that occurred on 2017 March 30. The prominence was observed simultaneously by several instruments, including the Interface Region Imaging Spectrograph (IRIS) and the Multichannel Subtractive Double Pass (MSDP) spectrograph operating at the Meudon solar tower. We…
An X-Ray Study of Coronally Connected Active Eclipsing Binaries
Pandey, J. C.; Singh, Gurpreet
We present a detailed X-ray analysis and imaging of stellar coronae of five coronally connected eclipsing binaries, namely, 44 Boo, DV Psc, ER Vul, XY UMa, and TX Cnc. Both components of these binaries are found to be active. The X-ray light curves of detached and semidetached type systems show eclipsed-like features, whereas no evidence for coron…
Mass-ratio Distribution of Binaries from the LAMOST-MRS Survey
Wang, Luqian; Han, Zhanwen; Chen, Xuefei +7 more
Binary evolution leads to the formation of important objects that are crucial for the development of astrophysics, but the statistical properties of binary populations are still poorly understood. The LAMOST-MRS has provided a large sample of stars to study the properties of binary populations, especially for the mass-ratio distributions and binar…
Effects of Hydrogen versus Helium on Electromagnetic Black Hole Observables
Gammie, Charles F.; Wong, George N.
The centers of our Galaxy and the nearby Messier 87 are known to contain supermassive black holes, which support accretion flows that radiate across the electromagnetic spectrum. Although the composition of the accreting gas is unknown, it is likely a mix of ionized hydrogen and helium. We use a simple analytic model and a suite of numerical gener…