Search Publications
The Absolute Age of NGC 3201 Derived from Detached Eclipsing Binaries and the Hess Diagram
Chaboyer, Brian; Ying, Jiaqi (Martin); Du, Wenxin
We estimate the absolute age of the globular cluster NGC 3201 using 10,000 sets of theoretical isochrones constructed through Monte Carlo simulation using the Dartmouth Stellar Evolution Program. These isochrones take into consideration the uncertainty introduced by the choice of stellar evolution parameters. We fit isochrones with three detached …
RR Lyrae Stars Belonging to the Candidate Globular Cluster Patchick 99
Clarkson, William I.; Rich, R. Michael; Kunder, Andrea +16 more
Patchick 99 is a candidate globular cluster located in the direction of the Galactic bulge, with a proper motion almost identical to the field and extreme field star contamination. A recent analysis suggests it is a low-luminosity globular cluster with a population of RR Lyrae stars. We present new spectra of stars in and around Patchick 99, targe…
On the Determining Physical Factor of Jet-related Coronal Mass Ejections' Morphology in the High Corona
Shen, Yuandeng; Duan, Yadan; Tang, Zehao +2 more
A solar jet can often cause coronal mass ejections (CMEs) with different morphologies in the high corona, for example, jet-like CMEs, bubble-like CMEs, and so-called twin CMEs that include a pair of simultaneous jet-like and bubble-like CMEs. However, what determines the morphology of a jet-related CME is still an open question. Using high spatiot…
On the Origin of Fast-rotating Stars. I. Photometric Calibration and Results of AO-assisted BVRI+Hα Imaging of NGC 330 with SAMI/SOAR
Navarete, Felipe; Ticiani dos Santos, Pedro; Carciofi, Alex Cavaliéri +1 more
Hα emission is a clear indicator of circumstellar activity in Be stars, historically employed to assess the classical Be star (CBe) population in young open clusters (YOCs). The YOC NGC 330 in the Small Magellanic Cloud exhibits a large known fraction of CBe stars and was selected for a pilot study to establish a comprehensive methodology for iden…
Pulsed Iron Line Emission from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124
Zhang, S.; Tao, L.; Zhang, S. N. +14 more
We report the phase-resolved spectral results of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124, modeling its 2017–2018 outburst peak using data collected by the Hard X-ray Modulation Telescope (Insight-HXMT). The broad energy coverage of Insight-HXMT allows us to obtain a more accurate spectral continuum to redu…
Global Impact of Emerging Internetwork Fields on the Low Solar Atmosphere
Gošić, M.; De Pontieu, B.; Sainz Dalda, A.
Small-scale, newly emerging internetwork (IN) magnetic fields are considered a viable source of energy and mass for the solar chromosphere and possibly the corona. Multiple studies show that single events of flux emergence can indeed locally heat the low solar atmosphere through interactions of the upward propagating magnetic loops and the preexis…
The Radio Halo in PLCKESZ G171.94–40.65: Beacon of Merging Activity
Brunetti, G.; Wik, D. R.; Santra, R. +6 more
We present the first multifrequency analysis of the candidate ultrasteep spectrum radio halo in the galaxy cluster PLCKESZ G171.94‑40.65, using the upgraded Giant Metrewave Radio telescope (400 MHz), and Karl G. Jansky Very Large Array (1–2 GHz) observations. Our radio data have been complemented with archival Chandra X-ray observations to provide…
A Gamma-Ray Flare from TXS 1508+572: Characterizing the Jet of a z = 4.31 Blazar in the Early Universe
Wilms, Jörn; Kadler, Matthias; Smith, Paul S. +13 more
Blazars can be detected from very large distances due to their high luminosity. However, the detection of γ-ray emission of blazars beyond z = 3 has only been confirmed for a small number of sources. Such observations probe the growth of supermassive black holes close to the peak of star formation in the history of galaxy evolution. As a result fr…
Advancing Precision Particle Background Estimation for Future X-Ray Missions: Correlated Variability between the Alpha Magnetic Spectrometer and Chandra/XMM-Newton
Miller, Eric D.; Kraft, Ralph P.; Wilkins, Dan +9 more
Galactic cosmic-ray (GCR) particles have a significant impact on the particle-induced background of X-ray observatories, and their flux exhibits substantial temporal variability, potentially influencing background levels. In this study, we present 1 day binned high-energy reject rates derived from the Chandra-ACIS and XMM-Newton EPIC-pn instrument…
Weak Lensing Analysis of A2390 Using Short Exposures
Li, G.; Bonafede, A.; Peterson, J. R. +4 more
We present a weak lensing analysis of the galaxy cluster A2390 at z = 0.23 using second moment shape measurements made in 411 short 60 s exposures. The exposures are obtained in three broadband photometric filters (g, r, and i) using WIYN-ODI. Shape measurement in individual exposures is done using a moment-matching algorithm. Forced measurement i…