Search Publications
A Light Curve Analysis of Classical Novae: Free-free Emission versus Photospheric Emission
Kato, Mariko; Hachisu, Izumi
We analyzed light curves of seven relatively slower novae, PW Vul, V705 Cas, GQ Mus, RR Pic, V5558 Sgr, HR Del, and V723 Cas, based on an optically thick wind theory of nova outbursts. For fast novae, free-free emission dominates the spectrum in optical bands rather than photospheric emission, and nova optical light curves follow the universal dec…
Chitah: Strong-gravitational-lens Hunter in Imaging Surveys
Marshall, Philip J.; Oguri, Masamune; Suyu, Sherry H. +5 more
Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling t…
Detection of Quasar Feedback from the Thermal Sunyaev-Zel’dovich Effect in Planck
Anderson, Scott F.; Ruan, John J.; McQuinn, Matthew
Poorly understood feedback processes associated with highly luminous black hole accretion in quasars may dramatically affect the properties of their host galaxies. We search for the effect of quasar feedback on surrounding gas using Planck maps of the thermal Sunyaev-Zel’dovich effect (tSZ). By stacking tSZ Compton-y maps centered on the locations…
Star Cluster Properties in Two LEGUS Galaxies Computed with Stochastic Stellar Population Synthesis Models
Gouliermis, Dimitrios A.; Smith, Linda J.; Calzetti, Daniela +14 more
We investigate a novel Bayesian analysis method, based on the Stochastically Lighting Up Galaxies (slug) code, to derive the masses, ages, and extinctions of star clusters from integrated light photometry. Unlike many analysis methods, slug correctly accounts for incomplete initial mass function (IMF) sampling, and returns full posterior probabili…
Hubble Space Telescope Astrometry of the Procyon System
Schaefer, Gail H.; Nelan, Edmund P.; Bond, Howard E. +9 more
The nearby star Procyon is a visual binary containing the F5 IV-V subgiant Procyon A, orbited in a 40.84-year period by the faint DQZ white dwarf (WD) Procyon B. Using images obtained over two decades with the Hubble Space Telescope, and historical measurements back to the 19th century, we have determined precise orbital elements. Combined with me…
FIP Bias Evolution in a Decaying Active Region
Long, D. M.; van Driel-Gesztelyi, L.; Démoulin, P. +4 more
Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode’s EUV Imaging Spectrometer instrument, we present a series of large-scale, spatially resolved composition maps of active region (AR)11389. The composition maps show how FIP bias evolves within the decaying AR durin…
Revisiting the ISN Flow Parameters, Using a Variable IBEX Pointing Strategy
Wurz, P.; McComas, D. J.; Fuselier, S. A. +8 more
The Interstellar Boundary Explorer (IBEX) has observed the interstellar neutral (ISN) gas flow over the past 6 yr during winter/spring when the Earth’s motion opposes the ISN flow. Since IBEX observes the interstellar atom trajectories near their perihelion, we can use an analytical model based upon orbital mechanics to determine the interstellar …
Solar Sources of 3He-rich Solar Energetic Particle Events in Solar Cycle 24
Nitta, Nariaki V.; Mason, Glenn M.; Wang, Linghua +2 more
Using high-cadence EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 3He-rich solar energetic particle events at ≲1 MeV nucleon-1 that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the…
The Structure of HE 1104-1805 from Infrared to X-Ray
Chen, Bin; Kochanek, Christopher S.; Dai, Xinyu +2 more
The gravitationally lensed quasar HE 1104-1805 has been observed at a variety of wavelengths ranging from the mid-infrared to X-ray for nearly 20 yr. We combine flux ratios from the literature, including recent Chandra data, with new observations from the SMARTS telescope and Hubble Space Telescope, and use them to investigate the spatial structur…
Sixteen Years of Ulysses Interstellar Dust Measurements in the Solar System. III. Simulations and Data Unveil New Insights into Local Interstellar Dust
Krüger, Harald; Sterken, Veerle J.; von Steiger, Rudolf +2 more
Interstellar dust (ISD) in the solar system was detected in situ for the first time in 1993 by the Ulysses dust detector. The study of ISD is important for understanding its role in star and solar system formation. The goal of this paper is to understand the variability in the ISD observations from the Ulysses mission by using a Monte Carlo simula…