Search Publications
A SOFIA FORCAST Grism Study of the Mineralogy of Dust in the Winds of Proto-planetary Nebulae: RV Tauri Stars and SRd Variables
Gehrz, R. D.; Lebzelter, T.; Hinkle, K. H. +10 more
We present a SOFIA FORCAST grism spectroscopic survey to examine the mineralogy of the circumstellar dust in a sample of post-asymptotic giant branch (post-AGB) yellow supergiants that are believed to be the precursors of planetary nebulae. Our mineralogical model of each star indicates the presence of both carbon-rich and oxygen-rich dust species…
Probing Large Galaxy Halos at Z ∼ 0 with Automated Lyα-absorption Matching
Wakker, Bart P.; French, David M.
We present initial results from an ongoing large-scale study of the circumgalactic medium in the nearby Universe ({cz} ≤slant 10,000 {km} {{{s}}}-1), using archival Cosmic Origins Spectrograph spectra of background quasi-stellar objects. This initial sample contains 33 sightlines chosen for their proximity to large galaxies (D≥slant 25 …
Computation of the Transmitted and Polarized Scattered Fluxes by the Exoplanet HD 189733b in X-Rays
Marin, Frédéric; Grosso, Nicolas
Thousands of exoplanets have been detected, but only one exoplanetary transit was potentially observed in X-rays from HD 189733A. What makes the detection of exoplanets so difficult in this band? To answer this question, we run Monte-Carlo radiative transfer simulations to estimate the amount of X-ray flux reprocessed by HD 189733b. Despite its ex…
A Bayesian Approach to Period Searching in Solar Coronal Loops
McKenzie, David; Scherrer, Bryan
We have applied a Bayesian generalized Lomb-Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each lig…
Discovery of a Rapid, Luminous Nova in NGC 300 by the KMTNet Supernova Program
Kim, Dong-Jin; Lee, Yongseok; Moon, Dae-Sik +3 more
We present the discovery of a rapidly evolving transient by the Korean Microlensing Telescope Network Supernova Program (KSP). KSP is a novel high-cadence supernova survey that offers deep (∼21.5 mag in BV I bands), nearly continuous wide-field monitoring for the discovery of early and/or fast optical transients. KSP-OT-201509a, reported here, was…
The Evolution of Bulge-dominated Field Galaxies from z ≈ 1 to the Present
Jørgensen, Inger; Woodrum, Charity; Demarco, Ricardo +4 more
We analyze the stellar populations and evolutionary history of bulge-dominated field galaxies at redshifts 0.3< z< 1.2 as part of the Gemini/Hubble Space Telescope (HST) Galaxy Cluster Project (GCP). High signal-to-noise optical spectroscopy from the Gemini Observatory and imaging from the HST are used to analyze a total of 43 galaxies, focu…
Thermal Pressure in Diffuse H2 Gas Measured by Herschel [C II] Emission and FUSE UV H2 Absorption
Goldsmith, P. F.; Langer, W. D.; Pineda, J. L. +1 more
UV absorption studies with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite have made important observations of H2 molecular gas in Galactic interstellar translucent and diffuse clouds. Observations of the 158 µm [C II] fine-structure line with Herschel trace the same H2 molecular gas in emission. We present …
Calibrating Column Density Tracers with Gamma-Ray Observations of the ρ Ophiuchi Molecular Cloud
Teachey, Alex; Abrahams, Ryan D.; Paglione, Timothy A. D.
Diffuse gamma-ray emission from interstellar clouds results largely from cosmic ray (CR) proton collisions with ambient gas, regardless of the gas state, temperature, or dust properties of the cloud. The interstellar medium is predominantly transparent to both CRs and gamma-rays, so GeV emission is a unique probe of the total gas column density. T…
Long-term Longitudinal Recurrences of the Open Magnetic Flux Density in the Heliosphere
Dósa, M.; Erdős, G.
Open magnetic flux in the heliosphere is determined from the radial component of the magnetic field vector measured onboard interplanetary space probes. Previous Ulysses research has shown remarkable independence of the flux density from heliographic latitude, explained by super-radial expansion of plasma. Here we are investigating whether any lon…
Nanograin Density Outside Saturn’s A Ring
Persoon, A. M.; Johnson, Robert E.; Tseng, Wei-Ling +1 more
The observed disparity between the radial dependence of the ion and electron densities measured by the Cassini plasma (CAPS) and radio (RPWS) science instruments are used to show that the region between the outer edge of Saturn’s main rings and its tenuous G ring is permeated with small charged grains (nanograins). These grains emanate from the ed…