Search Publications
The Guitar Filament's Magnetic Field Revealed by Starlight Polarization
Liodakis, Ioannis; Romani, Roger W.; Dinsmore, Jack T. +2 more
The Guitar nebula surrounding PSR B2224+65 boasts a pulsar X-ray filament likely aligned with the local magnetic field. We present new RoboPol stellar polarization data distributed along the line of sight to the pulsar. The polarizing effect of intervening magnetized dust allows us to extract a model for the dust-weighted magnetic field. We detect…
Suzaku Observations of the Cold Front in A3667: A Nonequilibrium Ionization State of the Intracluster Medium
Kohmura, Takayoshi; Uchida, Yuusuke; Shishido, Mona
We present a systematic study of the thermodynamic properties of the intracluster medium (ICM), including the plasma conditions in the ICM, in the merging galaxy cluster A3667 using Suzaku. We analyze the X-ray spectra of the ICM between the northwestern and the southeastern radio relics across a prominent cold front in A3667 to search for the ICM…
Solar Variability in the Mg II h and k Lines
Solanki, S. K.; Shapiro, A. I.; Krivova, N. A. +3 more
Solar irradiance and its variations in the ultraviolet (UV) control the photochemistry in Earth's atmosphere and influence Earth's climate. The variability in the Mg II h and k core-to-wing ratio, also known as the Mg II index, is highly correlated with the solar UV irradiance variability. Because of this, the Mg II index is routinely used as a pr…
A Planet Candidate Orbiting near the Hot Jupiter TOI-2818 b Inferred through Transit Timing
Winn, Joshua N.; Montet, Benjamin T.; Hartman, Joel D. +5 more
TOI-2818 b is a hot Jupiter orbiting a slightly evolved G-type star on a 4.04 day orbit that shows transit timing variations (TTVs) suggestive of a decreasing orbital period. In the most recent year of TESS observations, transits were observed ∼8 minutes earlier than expected for a constant period. The implied orbital decay rate is 1.35 ± 0.25 s y…
Estimation of Transit Time of CMEs from the Sun to Earth
Ravishankar, Anitha; Michałek, Grzegorz; Pattnaik, Ashutosh
Coronal mass ejections (CMEs) can cause severe geomagnetic storms on Earth, making it essential to forecast their arrival. However, predicting the transit time (TT) of Earth-directed CMEs is challenging due to the complex factors involved, such as CME dynamics, the state of the interplanetary medium, and CME interactions. Our goal is to predict th…
Green Peas in the Southern Sky: Broadband Color Selection and Spectroscopic Follow-up
Lee, Jeong Hwan; Shim, Hyunjin; Jeong, Yejin +1 more
We present a systematic search for 1696 green pea (GP) galaxy candidates in the southern hemisphere selected from the Dark Energy Survey Data Release 2 and provide preliminary results from spectroscopic follow-up observations of 26 targets chosen among them. Our selection criteria include the colors in the gri bands and compact morphology in the c…
Analysis of Solar Eruptions Deflecting in the Low Corona: Influence of the Magnetic Environment
Vourlidas, Angelos; Mac Cormack, Cecilia; Sahade, Abril
Coronal mass ejections (CMEs) can exhibit nonradial evolution. The background magnetic field is considered the main driver for the trajectory deviation relative to the source region. The influence of the magnetic environment has been largely attributed to the gradient of the magnetic pressure. In this work, we propose a new approach for investigat…
Fast-rotating A- and F-type Stars with Hα Emissions in NGC 3532: Candidate UV-dim Stars?
Li, Gang; Li, Chengyuan; He, Chenyu
Extended main-sequence stars that are dim in the ultraviolet passbands of the Hubble Space Telescope (UV-dim stars) are found in several young and intermediate-age star clusters in the Magellanic Clouds (MCs). The obscuring of the dust in the disks of stars expelled as a result of fast rotation has been suggested to be responsible for the appearan…
Simultaneous Existence of Oscillations, Counterstreaming Flows, and Mass Injections in Solar Quiescent Prominences
Xu, Zhe; Xue, Zhike; Yan, Xiaoli +8 more
Solar prominences are very spectacular structures embedded in the tenuous and hot solar corona. Counterstreaming flows, a common feature in solar quiescent prominences, have been discovered for more than 20 yr. However, the mechanism driving the counterstreaming flows is still elusive. To unveil the nature of this phenomenon, we analyzed data of a…
X-Ray Emission Properties of a Compact Symmetric Object Sample
Yao, Su; Zhang, Hai-Ming; Zhang, Jin +2 more
We present a comprehensive analysis of the X-ray observations obtained from XMM-Newton and Chandra for a sample of bona-fide Compact Symmetric Objects (CSOs) to investigate their X-ray emission properties. Ultimately, we obtain 32 effective X-ray observational spectra from 17 CSOs. Most spectra can be well described by an absorbed single power-law…