Search Publications
The Formation Process of the First Halo Coronal Mass Ejection in Solar Cycle 25: Magnetic Cancellation, Bidirectional Jet, and Hot Channel
Xue, Zhike; Yan, Xiaoli; Wang, Jincheng +3 more
To better understand the trigger mechanism of a coronal mass ejection (CME), we present the evolution of a CME source region (active region NOAA 12790) and the formation of a hot channel before the occurrence of the first halo CME in solar cycle 25. Through analyzing the evolution of Solar Dynamics Observatory/Helioseismic and Magnetic Imager line…
Longitudinally Resolved Spectral Retrieval (ReSpect) of WASP-43b
Gonzales, Eileen C.; Cubillos, Patricio E.; Cowan, Nicolas B. +6 more
Thermal phase variations of short-period planets indicate that they are not spherical cows: day-to-night temperature contrasts range from hundreds to thousands of degrees, rivaling their vertical temperature contrasts. Nonetheless, the emergent spectra of short-period planets have typically been fit using one-dimensional (1D) spectral retrieval co…
Synthetic Absorption Lines from Simulations of Multiphase Gas in Galactic Winds
Ostriker, Eve C.; de la Cruz, Lita M.; Schneider, Evan E.
Supernova-driven galactic winds are multiphase streams of gas that are often observed flowing at a range of velocities out of star-forming regions in galaxies. In this study, we use high-resolution 3D simulations of multiphase galactic winds modeled with the hydrodynamics code Cholla to investigate the connection between numerical studies and obse…
Late-time Hubble Space Telescope Observations of a Hydrogen-poor Superluminous Supernova Reveal the Power-law Decline of a Magnetar Central Engine
Berger, Edo; Chornock, Ryan; Nicholl, Matt +3 more
The light-curve diversity of hydrogen-poor superluminous supernovae (SLSNe) has kept open the possibility that multiple power sources account for the population. Specifically, pair-instability explosions (PISNe), which produce large masses of 56Ni, have been argued as the origin of some slowly-evolving SLSNe. Here we present detailed ob…
Solar Modulation of Galactic Cosmic-Ray Protons Based on a Modified Force-field Approach
Qin, Gang; Shen, Zhenning; Yang, Hao +4 more
In this work, a modified force-field approach is established to investigate the long-term solar modulation of galactic cosmic-ray (GCR) protons. In this approach, the solar modulation potential φ is assumed to be energy dependent. As φ also depends on the local interstellar spectrum (LIS), a new proton LIS model is first presented based on data fr…
A LAMOST BHB Catalog and Kinematics Therein. I. Catalog and Halo Properties
Shen, Juntai; Smith, Martin C.; Li, Zhao-Yu +1 more
In this paper, we collect a sample of stars observed both in LAMOST and Gaia, which have colors implying a temperature hotter than 7000 K. We train a machine-learning algorithm on LAMOST spectroscopic data which has been tagged with stellar classifications and metallicities, and use this machine to construct a catalog of blue horizontal branch sta…
The Cepheid Distance to the Narrow-line Seyfert 1 Galaxy NGC 4051
Ferrarese, L.; Vestergaard, M.; Peterson, B. M. +15 more
We derive a distance of D = 16.6 ± 0.3 Mpc (µ = 31.10 ± 0.04 mag) to the archetypal narrow-line Seyfert 1 galaxy NGC 4051 based on Cepheid period-luminosity relations and new Hubble Space Telescope multiband imaging. We identify 419 Cepheid candidates and estimate the distance at both optical and near-infrared wavelengths using subsamples of…
The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. II. The Star-formation History of Andromeda I Derived from Long-period Variables
Javadi, Atefeh; Saremi, Elham; van Loon, Jacco Th. +4 more
An optical monitoring survey in the nearby dwarf galaxies was carried out with the 2.5 m Isaac Newton Telescope. 55 dwarf galaxies and four isolated globular clusters in the Local Group were observed with the Wide Field Camera. The main aims of this survey are to identify the most evolved asymptotic giant branch stars and red supergiants at the en…
Spatially Resolved BPT Mapping of Nearby Seyfert 2 Galaxies
Elvis, Martin; Storchi-Bergmann, Thaisa; Fabbiano, G. +5 more
We present spatially resolved Baldwin-Phillips-Terlevich (BPT) mapping of the extended narrow-line regions (ENLRs) of seven nearby Seyfert 2 galaxies, using Hubble Space Telescope narrowband filter imaging. We construct the BPT diagrams using ≤0"1 resolution emission line images of [O III] λ5007, Hα, [S II] λλ6717, 6731, and Hβ. By mapping these d…
Predicting the Spectrum of UGC 2885, Rubin's Galaxy with Machine Learning
Holwerda, Benne W.; Bailin, Jeremy; Böker, Torsten +10 more
Wu & Peek predict SDSS-quality spectra based on Pan-STARRS broadband grizy images using machine learning (ML). In this article, we test their prediction for a unique object, UGC 2885 ("Rubin's galaxy"), the largest and most massive, isolated disk galaxy in the local universe (D < 100 Mpc). After obtaining the ML predicted spectrum, we compa…