Search Publications
Implications of a Time-varying Galactic Potential for Determinations of the Dynamical Surface Density
Hernquist, Lars; Famaey, Benoit; Haines, Tim +2 more
We analyze a high-resolution N-body simulation of a live stellar disk perturbed by the recent passage of a massive dwarf galaxy that induces a wobble, in-plane rings, and phase spirals in the disk. The implications of the phase-space structures and the estimate of the matter density through traditional Jeans modeling are investigated. The dwarf sa…
Observational Analysis on the Early Evolution of a CME Flux Rope: Preflare Reconnection and Flux Rope’s Footpoint Drift
Yang, Jiayan; Ji, Kaifan; Duan, Yadan +1 more
We study the early evolution of a hot-channel-like magnetic flux rope (MFR) toward eruption. Combining with imaging observation and magnetic field extrapolation, we find that the hot channel possibly originated from a preexisting seed MFR with a hyperbolic flux tube (HFT). In the precursor phase, three-dimensional tether-cutting reconnection at th…
The Formation Conditions of the Wide Binary Class 0 Protostars within BHR 71
Bourke, Tyler L.; Codella, Claudio; Chen, Xuepeng +7 more
We present a characterization of the binary protostar system that is forming within a dense core in the isolated dark cloud BHR71. The pair of protostars, IRS1 and IRS2, are both in the Class 0 phase, determined from observations that resolve the sources from 1 µm out to 250 µm and from 1.3 mm to 1.3 cm. The resolved observations enabl…
A Secondary Fan-spine Magnetic Structure in Active Region 11897
Hou, Yijun; Li, Ting; Yang, Shuhong +1 more
Fan-spine is a special topology in solar atmosphere and is closely related to magnetic null point, as well as circular-ribbon flares, which can provide important information for understanding the intrinsic 3D nature of solar flares. However, the fine structure within the fan has rarely been investigated. In present paper, we investigate a secondar…
Search for Gravitational-wave Signals Associated with Gamma-Ray Bursts during the Second Observing Run of Advanced LIGO and Advanced Virgo
Lee, H. M.; Williams, D.; Hurley, K. +1196 more
We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have analyzed 98 gamma-ray bursts using an unmodeled search method that searches for generic transient gravitation…
Cloud Atlas: Rotational Spectral Modulations and Potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C
Schneider, Glenn; Apai, Dániel; Burgasser, Adam J. +11 more
Measurements of photometric variability at different wavelengths provide insights into the vertical cloud structure of brown dwarfs and planetary-mass objects. In seven Hubble Space Telescope consecutive orbits, spanning ∼10 hr of observing time, we obtained time-resolved spectroscopy of the planetary-mass T8 dwarf Ross 458 C using the near-infrar…
Multi-component Decomposition of Astronomical Spectra by Compressed Sensing
Winebarger, Amy R.; Antolin, Patrick; Testa, Paola +9 more
The signal measured by an astronomical spectrometer may be due to radiation from a multi-component mixture of plasmas with a range of physical properties (e.g., temperature, Doppler velocity). Confusion between multiple components may be exacerbated if the spectrometer sensor is illuminated by overlapping spectra dispersed from different slits, wi…
Not So Heavy Metals: Black Hole Feedback Enriches the Circumgalactic Medium
Werk, Jessica K.; Pontzen, Andrew; Christensen, Charlotte +4 more
We examine the effects of supermassive black hole (SMBH) feedback on the circumgalactic medium (CGM) using a cosmological hydrodynamic simulation (ROMULUS25) and a set of four zoom-in “genetically modified” Milky-Way-mass galaxies sampling different evolutionary paths. By tracing the distribution of metals in the CGM, we show that O VI is a sensit…
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. X. Optical Variability Characteristics
Ho, Luis C.; Bian, Wei-Hao; Zhang, Zhi-Xiang +11 more
We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns, including our ongoing campaign of monitoring super-Eddington accreting massive black holes (BHs). This sample covers a large range of BH mass ({M}\bullet ={10}6{--9} {M}⊙ ), dimensionless accreti…
Quiescent Galaxy Size and Spectroscopic Evolution: Combining HSC Imaging and Hectospec Spectroscopy
Geller, Margaret J.; Utsumi, Yousuke; Damjanov, Ivana +3 more
We explore the relationships between size, stellar mass, and average stellar population age (indicated by D n 4000 indices) for a sample of ∼11,000 intermediate-redshift galaxies from the SHELS spectroscopic survey (Geller et al. 2014) augmented by high-resolution Subaru Telescope Hyper Suprime-Cam imaging. In the redshift interval 0.1…