Search Publications
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 …
Kinematics and Star Formation in the Hub–Filament System G6.55-0.1
Wyrowski, Friedrich; Güsten, Rolf; Ishwara-Chandra, C. H. +2 more
Hub–filament systems (HFSs) being the potential sites of formation of star clusters and high-mass stars, provide a testbed for the current theories that attempt to explain star formation globally. It is thus important to study a large number of HFSs using both intensity and velocity information to constrain these objects better observationally. He…
A Quantification of the Effects Using Different Stellar-population Synthesis Models for Epoch of Reionization
Luo, Rongxin; Han, Yunkun; Liu, Peiai +1 more
The luminosity and spectral energy distribution of high-z galaxies are sensitive to the stellar-population synthesis (SPS) models. In this paper, we study the effects of different SPS models on the measurements of high-z galaxies and the budget of ionizing photons during the epoch of reionization by employing each of them in the semianalytical gal…
Quasi-stars as a Means of Rapid Black Hole Growth in the Early Universe
Begelman, Mitchell C.; Coughlin, Eric R.
JWST observations demonstrate that supermassive black holes (SMBHs) exist by redshifts z ≳ 10, providing further evidence for "direct collapse" black hole (BH) formation, whereby massive (∼103–5 M ⊙) SMBH seeds are generated within a few million years as a byproduct of the rapid inflow of gas into the centers of protogalaxies…
The JWST Resolved Stellar Populations Early Release Science Program. VII. Stress Testing the NIRCam Exposure Time Calculator
Gennaro, Mario; McQuinn, Kristen B. W.; Dolphin, Andrew E. +19 more
We empirically assess estimates from v3.0 of the James Webb Space Telescope NIRCam Exposure Time Calculator (ETC) using observations of resolved stars in Local Group targets taken as part of the Resolved Stellar Populations Early Release Science (ERS) Program. For bright stars, we find that (i) purely Poissonian estimates of the signal-to-noise ra…
All-sky Kinematics and Chemistry of Monoceros Stellar Overdensity
Laporte, Chervin F. P.; Antoja, Teresa; Limberg, Guilherme +7 more
We explore the kinematic and chemical properties of the Monoceros stellar overdensity by combining data from the Two Micron All Sky Survey, Wide-field Infrared Survey Explorer, APOGEE, and Gaia. Monoceros is a structure located toward the Galactic anticenter and close to the disk. We have identified that its stars have azimuthal velocity in the ra…
An HI-absorption-selected Cold Rotating Disk Galaxy at z ≈ 2.193
Prochaska, J. X.; Rafelski, M.; Dutta, R. +3 more
We have used the Atacama Large Millimeter/submillimeter Array to map CO(3–2) emission from a galaxy, DLA-B1228g, associated with the high-metallicity damped Lyα absorber at z ≈ 2.1929 toward the QSO PKS B1228–113. At an angular resolution of ≈0.″32 × 0.″24, DLA-B1228g shows extended CO(3–2) emission with a deconvolved size of ≈0.″78 × 0.″18, i.e.,…