Search Publications
Detailed asteroseismic modelling of RR Lyrae stars with non-radial modes
Molnár, L.; Netzel, H.; Joyce, M.
Photometric observations from the last decade have revealed additional low-amplitude periodicities in many classical pulsators that are likely due to pulsations in non-radial modes. One group of multimode RR Lyrae stars, the so-called 0.61 stars, is particularly interesting. In these stars, the radial first overtone is accompanied by additional si…
Cold mode gas accretion on two galaxy groups at z ∼ 2
Zakamska, Nadia L.; Armus, Lee; Wright, Shelley A. +5 more
We present Keck Cosmic Web Imager (KCWI) integral field spectroscopy (IFS) observations of rest-frame UV emission lines $\rm Ly\alpha$, CIVλλ 1548 Å, 1550Å, and $\rm HeII$ 1640 Å observed in the circumgalactic medium (CGM) of two z = 2 radio-loud quasar host galaxies. We detect extended emission on 80-90 kpc scale in $\rm Ly\alpha$ in both systems…
Solar Coronal Density Turbulence and Magnetic Field Strength at the Source Regions of Two Successive Metric Type II Radio Bursts
Kumari, Anshu; Ramesh, R.; Kathiravan, C.
We report spectral and polarimeter observations of two weak, low-frequency (≈85-60 MHz) solar coronal type II radio bursts that occurred on 2020 May 29 within a time interval ≈2 minutes. The bursts had fine structures, and were due to harmonic plasma emission. Our analysis indicates that the magnetohydrodynamic shocks responsible for the first and…
Spectroscopically Identified Cataclysmic Variables from the LAMOST Survey. II. Period Estimates
Luo, A. -Li; Hou, Wen; Bai, Zhong-Rui +2 more
We examine a sample of 340 cataclysmic variables (CVs) from the latest data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey, along with 18 objects that are newly classified as CVs. In this paper, we focus on investigating the photometric behaviors of these CVs using data from time-domain surveys. The orbita…
CO Survey of High-z Radio Galaxies, Revisited with the Atacama Large Millimeter/submillimeter Array: Jet-Cloud Alignments and Synchrotron Brightening by Molecular Gas in the Circumgalactic Environment
Carilli, Chris; Lehnert, Matthew D.; De Breuck, Carlos +6 more
Powerful radio sources associated with supermassive black holes are among the most luminous objects in the universe, and are frequently recognized both as cosmological probes and active constituents in the evolution of galaxies. We present alignments between radio jets and cold molecular gas in the environment of distant radio galaxies, and show t…
Models for metal-poor stars with different initial abundances of C, N, O, Mg, and Si - III. Grids of isochrones for -2.5 ≤ [Fe/H] ≤ -0.5 and helium abundances Y = 0.25 and 0.29 at each metallicity
VandenBerg, Don A.
Stellar evolutionary tracks for $0.12 \le {\cal M}/{\cal M_{\odot }}\le 1.0$ have been computed for each of several variations in the abundances of C, N, and O, assuming mass-fraction helium abundances Y = 0.25 and 0.29, and 11 metallicities in the range -2.5 ≤ [Fe/H] ≤ -0.5, in 0.2-dex increments. Such computations are provided for mixtures with …
The impact of black hole scaling relation assumptions on the mass density of black holes
Simon, Joseph; Gültekin, Kayhan; Matt, Cayenne
We examine the effect of supermassive black hole (SMBH) mass scaling relation choice on the inferred SMBH mass population since redshift z ~ 3. To make robust predictions for the gravitational wave background (GWB), we must have a solid understanding of the underlying SMBH demographics. Using the SDSS and 3D-HST + CANDELS surveys for 0 < z <…
Periodic X-ray sources in the massive globular cluster 47 Tucanae: Evidence for dynamically formed cataclysmic variables
Li, Zhiyuan; Bao, Tong; Cheng, Zhongqun
We present a systematic study of periodic X-ray sources in the massive globular cluster 47 Tuc, utilizing deep archival Chandra observations that resolve the cluster core and recently available eROSITA observations that cover the cluster outskirt. By applying the Gregory-Loredo algorithm, we detect 20 periodic signals among 18 X-ray sources, rangi…
Large-scale Spatial Cross-calibration of Hinode/SOT-SP and SDO/HMI
Liu, Yang; Antiochos, Spiro K.; Leka, K. D. +7 more
We investigate the cross-calibration of the Hinode/Solar Optical Telescope-Spectro-Polarimeter (SOT-SP) and Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) instrument metadata, specifically the correspondence of the scaling and pointing information. Accurate calibration of these data sets gives the correspondence needed by in…
Carbon Dioxide Retrievals From NOMAD-SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profile Retrievals With the Hydrostatic Equilibrium Equation: 2. Temperature Variabilities in the Mesosphere at Mars Terminator
Aoki, S.; Vandaele, A. C.; Daerden, F. +14 more
The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument scans the Martian atmosphere since 21 April 2018. In this work, we present a subset of the NOMAD SO data measured at the mesosphere. We focused on a spectral range that started to be recorded in Martian year (MY) 35. A total of 968 vertical profil…