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Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548
Im, M.; Fox, O. D.; Malkan, M. A. +155 more
We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the Hβ, C IV, and Lyα broad emission lines. We find an extended disk-like Hβ BLR with…
COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-gravity T4 Benchmark around an Old White Dwarf and a Re-examination of the Surface-gravity Dependence of the L/T Transition
Magnier, Eugene A.; Hermes, J. J.; Marley, Mark S. +7 more
We present the first discovery from the COol Companions ON Ultrawide orbiTS (COCONUTS) program, a large-scale survey for wide-orbit planetary and substellar companions. We have discovered a comoving system COCONUTS-1, composed of a hydrogen-dominated white dwarf (PSO J058.9855+45.4184; d = 31.5 pc) and a T4 companion (PSO J058.9869+45.4296) at a 4…
Open Cluster Chemical Homogeneity throughout the Milky Way
Beaton, Rachael L.; Hawkins, K.; Cunha, K. +10 more
The chemical homogeneity of surviving stellar clusters contains important clues about interstellar medium (ISM) mixing efficiency, star formation, and the enrichment history of the Galaxy. Existing measurements in a handful of open clusters suggest homogeneity in several elements at the 0.03 dex level. Here we present (i) a new cluster member cata…
Models of the Mass-ejection Histories of Pre-planetary Nebulae. IV. Magnetized Winds and the Origins of Jets, Bullets, and FLIERs
Frank, Adam; Balick, Bruce; Liu, Baowei
This paper explores the influences and consequences of toroidal magnetic fields in shaping the visible lobes of pre-planetary nebulae (prePNe). To probe these influences we start with the steady, diverging, and field-free wind model of our previous papers and add weak to moderate toroidal fields to the winds in order to generate arrays of outcomes…
Self-consistent Analysis of Stellar Clusters: An Application to HST Data of the Halo Globular Cluster NGC 6752
Nardiello, D.; Barbuy, B.; Pérez-Villegas, A. +3 more
The Bayesian isochrone fitting using the Markov chain Monte Carlo algorithm is applied, to derive the probability distribution of the parameters age, metallicity, reddening, and absolute distance modulus. We introduce the SIRIUS code by means of simulated color-magnitude diagrams (CMDs), including the analysis of multiple stellar populations (MPs)…
Stellar Metallicities from SkyMapper Photometry I: A Study of the Tucana II Ultra-faint Dwarf Galaxy
Jerjen, Helmut; Frebel, Anna; Chiti, Anirudh +2 more
We present a study of the ultra-faint Milky Way dwarf satellite galaxy Tucana II using deep photometry from the 1.3 m SkyMapper telescope at Siding Spring Observatory, Australia. The SkyMapper filter set contains a metallicity-sensitive intermediate-band V filter covering the prominent Ca II K feature at 3933.7 Å. When combined with photometry fro…
Orbital Evidences for Dark-matter-free Milky Way Dwarf Spheroidal Galaxies
Hammer, Francois; Babusiaux, Carine; Bonifacio, Piercarlo +4 more
The nature of Milky Way dwarf spheroidals (MW dSphs) has been questioned, in particular whether they are dominated by dark matter (DM). Here we investigate an alternative scenario, for which tidal shocks are exerted by the MW to DM-free dSphs after a first infall of their gas-rich progenitors, and for which theoretical calculations have been verif…
Gravitational-wave Radiation of Double Degenerates with Extremely Low-mass White Dwarf Companions
Han, Zhanwen; Chen, Xuefei; Li, Zhenwei +3 more
Double degenerate (DD) systems are supposed to be significant gravitational-wave (GW) sources for future space-based GW detectors, e.g., the Laser Interferometer Space Antenna (LISA). Recently, one type of DD system with extremely low-mass WD (ELM WD; ≲ 0.30 M⊙) companions was found in the ELM Survey. These companions have very short or…
The Lyman Alpha Reference Sample. X. Predicting Lyα Output from Star-forming Galaxies Using Multivariate Regression
Hayes, Matthew; Östlin, Göran; Melinder, Jens +4 more
Understanding the production and escape of Lyα radiation from star-forming galaxies is a long-standing problem in astrophysics. The ability to predict the Lyα luminosity of galaxies would open up new ways of exploring the epoch of reionization (EOR) and estimating Lyα emission from galaxies in cosmological simulations where radiative transfer calc…
Astrophysical Distance Scale. II. Application of the JAGB Method: A Nearby Galaxy Sample
Madore, Barry F.; Freedman, Wendy L.
We apply the near-infrared J-region asymptotic giant branch (JAGB) method, recently introduced by Madore & Freedman, to measure the distances to 14 nearby galaxies out to 4 Mpc. We use the geometric detached eclipsing binary (DEB) distances to the LMC and SMC as independent zero-point calibrators. We find excellent agreement with previously pu…