Search Publications
The Messy Nature of Fiber Spectra: Star-Quasar Pairs Masquerading as Dual Type 1 AGNs
Bohn, Thomas; Pfeifle, Ryan W.; Secrest, Nathan J. +5 more
Theoretical studies predict that the most significant growth of supermassive black holes (SMBHs) occurs in late-stage mergers, coinciding with the manifestation of dual active galactic nuclei (AGNs), and both major and minor mergers are expected to be important for dual AGN growth. In fact, dual AGNs in minor mergers should be signposts for effici…
Splitting and Reconstruction of a Solar Filament Caused by Magnetic Emergence and Reconnection
Xu, Zhe; Xue, Zhike; Yan, Xiaoli +4 more
We present observations and interpretation of a nonerupting filament in NOAA active region (AR) 12827 that undergoes splitting and restructuring on 2021 June 4, using the high-resolution data obtained by the New Vacuum Solar Telescope, the Solar Dynamics Observatory, and the Interface Region Imaging Spectrograph. At the beginning, the right footpo…
A Broadband X-Ray Study of the Dwarf Nova SS Cyg during Quiescence and Outburst
Mukai, Koji; Dutta, Anirban; Rana, Vikram +1 more
We present a broadband X-ray study (~0.3-50 keV) of the dwarf nova SS Cyg highlighting the changes in the accretion during two phases, the quiescence and the outburst states. The investigation was based on simultaneous observations carried out with the XMM-Newton and NuSTAR telescopes in two epochs, involving medium- and high-resolution spectrosco…
Simulation of the Solar Energetic Particle Event on 2020 May 29 Observed by Parker Solar Probe
Balmaceda, Laura A.; Zhang, Ming; Lario, David +3 more
This paper presents a stochastic three-dimensional focused transport simulation of solar energetic particles (SEPs) produced by a data-driven coronal mass ejection (CME) shock propagating through a data-driven model of coronal and heliospheric magnetic fields. The injection of SEPs at the CME shock is treated using diffusive shock acceleration of …
The Equilibrium of Coronal Loops Near Separatrices
Antiochos, Spiro K.; Bradshaw, Stephen; Mason, Emily I.
We present numerical models from the field-aligned HYDrodynamics and RADiation code (HYDRAD) of a highly asymmetric closed coronal loop with near-singular expansion factor. This loop was chosen to simulate a coronal magnetic flux tube that passes close to a null point, as in the last set of closed loops under the fan surface of a coronal jet or a …
Raman Scattering by Atomic Hydrogen in Photodissociation Regions: An Alternative to the Polycyclic Aromatic Hydrocarbons Hypothesis
Zagury, Frédéric
Photodissociation regions (PDRs) illuminated by high temperature (T > 104 K) radiation fields display characteristic optical to midinfrared spectral features: emission bands that cluster around the blue limits of hydrogen series, an extended red emission (ERE) in the vicinity of Hα, and a continuum in the infrared part of the spectru…
Multifrequency Microwave Imaging of Weak Transients from the Quiet Solar Corona
Chen, Bin; Yu, Sijie; Mondal, Surajit
Understanding the dynamics of the quiet solar corona is important for answering key questions including the coronal heating problem. Multiple studies have suggested small-scale magnetic-reconnection events may play a crucial role. These reconnection events are expected to involve acceleration of electrons to suprathermal energies, which can then p…
Cannonball or Bowling Ball: Proper Motion and Parallax for PSR J0002+6216
Frail, D. A.; Kerr, M.; Schinzel, F. K. +4 more
We report the results of careful astrometric measurements of the cannonball pulsar J0002+6216 carried out over 3 yr using the High Sensitivity Array. We significantly refine the proper motion to µ = 35.3 ± 0.6 mas yr-1 and place new constraints on the distance, with the overall effect of lowering the velocity and increasing the in…
On the Short-period Eclipsing High-mass X-Ray Binary in NGC 4214
Soria, Roberto; Swartz, Douglas A.; Lin, Zikun
We present the results of our study of the luminous (L X ≈ 1039 erg s-1) X-ray binary CXOU J121538.2+361921 in NGC 4214, the high-mass X-ray binary with the shortest known orbital period. Using Chandra data, we confirm the ≈13,000 s (3.6 hr) eclipse period, and an eclipse duration of ≈2000 s. From this, we estimate…
Spicules in IRIS Mg II Observations: Automated Identification
Polito, Vanessa; Chamberlin, Phillip C.; Milligan, Ryan O. +4 more
We have developed an algorithm to identify solar spicules in the first ever systematic survey of on-disk spicules exclusively using Mg II spectral observations. Using this algorithm we identify 2021 events in three Interface Region Imaging Spectrograph (IRIS) data sets with unique solar feature targets spanning a total of 300 minutes: (1) active r…