Search Publications
Magnetic Field Extrapolation in Active Region Well Comparable to Observations in Multiple Layers
Zhu, Xiaoshuai; Li, Hui; Su, Yang +4 more
Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with non-negligible plasma β, where the crucial process of flux rope formation and evolution could happen. In this w…
Star-crossed Lovers DI Tau A and B: Orbit Characterization and Physical Properties Determination
Tang, Shih-Yun; Uyama, Taichi; Johns-Krull, Christopher M. +5 more
The stellar companion to the weak-line T Tauri star DI Tau A was first discovered by the lunar occultation technique in 1989 and was subsequently confirmed by a speckle imaging observation in 1991. It has not been detected since, despite being targeted by five different studies that used a variety of methods and spanned more than 20 yr. Here, we r…
The LSST AGN Data Challenge: Selection Methods
Ni, Qingling; Paolillo, Maurizio; Richards, Gordon T. +12 more
Development of the Rubin Observatory Legacy Survey of Space and Time (LSST) includes a series of Data Challenges (DCs) arranged by various LSST Scientific Collaborations that are taking place during the project's preoperational phase. The AGN Science Collaboration Data Challenge (AGNSC-DC) is a partial prototype of the expected LSST data on active…
A Comprehensive Perturbative Formalism for Phase Mixing in Perturbed Disks. II. Phase Spirals in an Inhomogeneous Disk Galaxy with a Nonresponsive Dark Matter Halo
van den Bosch, Frank C.; Banik, Uddipan; Weinberg, Martin D.
We develop a linear perturbative formalism to compute the response of an inhomogeneous stellar disk embedded in a nonresponsive dark matter (DM) halo to various perturbations like bars, spiral arms, and encounters with satellite galaxies. Without self-gravity to reinforce it, the response of a Fourier mode phase mixes away due to an intrinsic spre…
Formation of the Mg II h and k Polarization Profiles in a Solar Plage Model and Their Suitability to Infer Magnetic Fields
Afonso Delgado, David; del Pino Alemán, Tanausú; Trujillo Bueno, Javier
The Mg II h and k lines are among the strongest in the near-ultraviolet solar spectrum and their line core originates in the upper chromosphere, just below the transition region. Consequently, they have become one of the main targets for investigating the magnetism of the upper solar atmosphere. The recent Chromospheric Layer Spectropolarimeter (C…
The Dynamic Evolution of Multipoint Interplanetary Coronal Mass Ejections Observed with BepiColombo, Tianwen-1, and MAVEN
Zhang, Zhiyong; Zhang, Tielong; Su, Zhenpeng +28 more
We present two multipoint interplanetary coronal mass ejections (ICMEs) detected by the Tianwen-1 and Mars Atmosphere and Volatile Evolution spacecraft at Mars and the BepiColombo (0.56 au ~0.67 au) upstream of Mars from 2021 December 5 to 31. This is the first time that BepiColombo is used as an upstream solar wind monitor ahead of Mars and that …
Improving Distances to Binary Millisecond Pulsars with Gaia
Bedell, Megan; Spergel, David N.; Moran, Abigail +2 more
Pulsar distances are notoriously difficult to measure, and play an important role in many fundamental physics experiments, such as pulsar timing arrays. Here, we perform a cross-match between International PTA pulsars (IPTA) and Gaia's Data Release 2 (DR2) and Data Release 3 (DR3). We then combine the IPTA pulsar's parallax with its binary compani…
Constraining Fundamental Parameters in Modified Gravity Using Gaia-DR2 Massive White Dwarf Observations
Uniyal, Akhil; Kalita, Surajit
Various experiments and observations have led researchers to suggest different bounds on fundamental constants like the fine-structure constant and the proton-to-electron mass ratio. These bounds differ mostly due to the energy scale of the systems where the experiments are performed. In this article, we obtain bounds on these parameters in the mo…
The Period Distribution of Hot Jupiters Is Not Dependent on Host Star Metallicity
Winn, Joshua N.; Yee, Samuel W.
The probability that a Sun-like star has a close-orbiting giant planet (period ≲1 yr) increases with stellar metallicity. Previous work provided evidence that the period distribution of close-orbiting giant planets is also linked to metallicity, hinting that there two formation/evolution pathways for such objects, one of which is more probable in …
NY Bootes: An Active Deep and Low-mass-ratio Contact Binary with a Cool Companion in a Hierarchical Triple System
Meng, Fangbin; Zhu, Liying; Qian, Shengbang +3 more
The first detailed photometric and spectroscopic study of G-type short-period binary NY Boo is presented. The radial velocity curve was obtained by the cross-correlation function (CCF) method based on LAMOST and SDSS spectra, which derived its mass ratio as q = 0.139(1/7.2). The CCF profiles of the SDSS spectra clearly show the existence of a cool…