Search Publications
An Empirical Extinction Curve Revealed by Gaia XP Spectra and LAMOST
Zhang, Xiangyu; Wang, Tao; Huang, Bowen +4 more
We present a direct measurement of extinction curves using corrected Gaia XP spectra of the common sources in Gaia DR3 and LAMOST DR7. Our analysis of approximately 370,000 high-quality samples yielded a high-precision average extinction curve for the Milky Way. After incorporating infrared photometric data from Two Micron All Sky Survey and Wide-…
AWSoM Magnetohydrodynamic Simulation of a Solar Active Region. II. Statistical Analysis of Alfvén Wave Dissipation and Reflection, Scaling Laws, and Energy Budget on Coronal Loops
Landi, Enrico; van der Holst, Bart; Manchester, Ward +6 more
The coronal heating problem has been a major challenge in solar physics, and a tremendous amount of effort has been made over the past several decades to solve it. In this paper, we aim at answering how the physical processes behind the Alfvén wave turbulent heating adopted in the Alfvén Wave Solar atmosphere Model (AWSoM) unfold in individual pla…
New Results on the Onset of a Coronal Mass Ejection from 5303 Å Emission Line Observations with VELC/ADITYA-L1
Ramesh, R.; Singh, Jagdev; Sasikumar Raja, K. +3 more
We report on the onset of a coronal mass ejection (CME) using spectroscopic observations in the 5303 Å coronal emission line with the Visible Emission Line Coronagraph (VELC) onboard ADITYA-L1, the recently launched first Indian space solar mission. The CME was observed on 2024 July 16 in association with an X1.9 class soft X-ray flare from heliog…
The Orbit and Mass of the Cepheid AW Per
Mérand, Antoine; Lanthermann, Cyprien; Anugu, Narsireddy +17 more
The Cepheid AW Per is a component in a multiple system with a long-period orbit. The radial velocities of Griffin cover the 38 yr orbit well. An extensive program of interferometry with the Center for High Angular Resolution Astronomy array is reported here, from which the long-period orbit is determined. In addition, a Hubble Space Telescope high…
Two-process Model and Residual Abundance Analysis of the Milky Way Massive Satellites
Horta, Danny; Hayes, Christian R.; Beaton, Rachael L. +4 more
The "two-process model" is a promising technique for interpreting stellar chemical abundance data from large-scale surveys (e.g., the Sloan Digital Sky Survey IV/V and the Galactic Archeology with HERMES survey), enabling more quantitative empirical studies of differences in chemical enrichment history between galaxies without relying on detailed …
A Stellar Dynamical Mass Measurement of the Supermassive Black Hole in NGC 3258
Gebhardt, Karl; Gültekin, Kayhan; Nagar, Neil +2 more
We present a stellar dynamical mass measurement of the supermassive black hole in the elliptical (E1) galaxy NGC 3258. Our findings are based on integral field unit spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE) observations in narrow-field mode with adaptive optics and the MUSE wide-field mode, from which we extract kinematic info…
Classifying Optical (Out)bursts in Cataclysmic Variables: The Distinct Observational Characteristics of Dwarf Novae, Micronovae, Stellar Flares, and Magnetic Gating
Littlefield, Colin; Iłkiewicz, Krystian; Scaringi, Simone +5 more
Cataclysmic variables can experience short optical brightenings, which are commonly attributed to phenomena such as dwarf novae outbursts, micronovae, donor flares, or magnetic gating bursts. Since these events exhibit similar observational characteristics, their identification has often been ambiguous. In particular, magnetic gating bursts and mi…
Is It Possible to Detect Coronal Mass Ejections on Solar-type Stars through Extreme-ultraviolet Spectral Observations?
Tian, Hui; Yang, Zihao; Xu, Yu +3 more
Stellar coronal mass ejections (CMEs) from host stars are an important factor that affects the habitability of exoplanets. Although their solar counterparts have been well observed for decades, it is still very difficult to find solid evidence of stellar CMEs. Using the spectral line profile asymmetry caused by the Doppler shift of erupting plasma…
AB Dor: Coronal Imaging and Activity Cycles
Pandey, J. C.; Singh, Gurpreet
Using long-term X-ray observations, we present short-term and long-term X-ray variability analysis of the ultrafast rotating active star AB Dor. Flaring events are common in X-ray observations of AB Dor and occupy a substantial portion of the total observation time, averaging at around 57% ± 23%. The flare-free X-ray light curves show rotational m…
First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548
Gu, Liyi; Kriss, Gerard A.; Mehdipour, Missagh +5 more
Multiwavelength spectroscopy of NGC 5548 revealed remarkable changes due to the presence of an obscuring wind from the accretion disk. This broadened our understanding of obscuration and outflows in active galactic nuclei. Swift monitoring of NGC 5548 shows that over the last 10 yr, the obscuration has gradually declined. This provides a valuable …