Search Publications
The Formation of CME from Coupling Fan-spine Magnetic System: A Difficult Journey
Yang, Jiayan; Hong, Junchao; Chen, Hechao +1 more
We present the eruption of a mini-filament that caused a large-scale complicated coronal mass ejection (CME) on 2014 March 28, using the high-resolution observations taken by the Solar Dynamic Observatory. Three-dimensional coronal magnetic field extrapolated from the nonlinear force-free field code reveals that the magnetic environment of the eru…
Quantifying the Influence of Key Physical Processes on the Formation of Emission Lines Observed by IRIS. I. Non-equilibrium Ionization and Density-dependent Rates
Testa, Paola; Bradshaw, Stephen J.
In the work described here, we investigate atomic processes leading to the formation of emission lines within the Interface Region Imaging Spectrograph wavelength range at temperatures near 105 K. We focus on (1) non-equilibrium and (2) density-dependent effects influencing the formation and radiative properties of S IV and O IV. These …
Variable Warm Dust around the Herbig Ae Star HD 169142: Birth of a Ring?
Weigelt, Gerd; Moór, Attila; Kóspál, Ágnes +7 more
The Herbig Ae star HD 169142 is known to have a gaseous disk with a large inner hole, and also a photometrically variable inner dust component in the sub-astronomical-unit region. Following up on our previous analysis, we further studied the temporal evolution of inner dust around HD 169142, which may provide information on the evolution from late…
Variable Hard X-Ray Emission from the Central Star of the Eskimo Nebula
Toalá, Jesús A.; Guerrero, Martín A.; Chu, You-Hua
The central star of NGC 2392 shows the hardest X-ray emission among central stars of planetary nebulae (CSPNe). The recent discovery of a spectroscopic companion with an orbital period of 1.9 days could provide an explanation for its hard X-ray emission, as well as for the collimation of its fast outflow. Here, we analyze the available Chandra and…
Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37
Rieke, G. H.; Hodapp, Klaus W.; Meng, Huan Y. A. +5 more
We have monitored nearly a square degree in IC 1396A/Tr 37 over 21 epochs extending over 2014-2016 for sources variable in the JHK bands. In our data, 65% ± 8% of previously identified cluster members show variations, compared with ≲0.3% of field stars. We identify 119 members of Tr 37 on the basis of variability, forming an unbiased sample down t…
Transition Region Loops in the Very Late Phase of Flux Emergence in IRIS Sit-and-stare Observations
Fu, Hui; Li, Bo; Xia, Lidong +3 more
Loops are one of the fundamental structures that trace the geometry of the magnetic field in the solar atmosphere. Their evolution and dynamics provide a crucial proxy for studying how the magnetized structures are formed and heated in the solar atmosphere. Here, we report on spectroscopic observations of a set of transition-region loops taken by …
Chandra Detection of Intracluster X-Ray Sources in Fornax
Jin, Xiangyu; Li, Zhiyuan; Hou, Meicun +1 more
Based on archival Chandra observations with a total exposure of 1.3 Ms, we study X-ray point sources in the Fornax cluster of galaxies, with the primary aim of searching for intracluster X-ray source populations. We detect 1177 point sources out to a projected radius of ∼30 arcmin (∼180 kpc) from the cluster center and down to a limiting 0.5-8 keV…
Rovibrational Spectral Analysis of CO3 and C2O3: Potential Sources for O2 Observed in Comet 67P/Churyumov-Gerasimenko
Fortenberry, Ryan C.; Peters, Daniel; Ferrari, Brian C. +1 more
The recent ROSETTA mission to comet 67P/Churyumov-Gerasimenko detected surprisingly high levels of molecular oxygen (O2; hypervolatile species) in the coma. Current models predict that considerable levels of other hypervolatiles (such as molecular nitrogen, N2, methane, CH4, and Argon) should be found at similar le…
Secondary Radio and X-Ray Emissions from Galaxy Mergers
Murase, Kohta; Mészáros, Peter; Yuan, Chengchao
Shocks arising in galaxy mergers could accelerate cosmic-ray (CR) ions to TeV-PeV energies. While propagating in the intergalactic medium, these CRs can produce high-energy neutrinos, electron-positron pairs, and gamma-rays. In the presence of intergalactic magnetic fields, the secondary pairs will radiate observable emissions through synchrotron …
L1 Stream Deflection and Ballistic Launching at the Disk Bow Shock: An Absorption-line Velocity Analysis in Semi-detached Binaries
Godon, Patrick
Observations of semi-detached interacting binaries reveal orbital modulation in the optical, UV, and X-ray bands, indicating the presence of absorbing material obscuring the disk and accreting primary star at specific orbital phases consistent with L1 stream material overflowing the disk edge. We simulate the L1 stream interaction with the disk us…