Search Publications
Evolution of C IV Absorbers. II. Where Does C IV Live?
Kacprzak, Glenn G.; Churchill, Christopher W.; Nielsen, Nikole M. +4 more
We use the observed cumulative statistics of C IV absorbers and dark matter halos to infer the distribution of C IV-absorbing gas relative to galaxies at redshifts 0 ≤ z ≤ 5. We compare the cosmic incidence dN/dX of C IV absorber populations and galaxy halos, finding that massive L ≥ L ⋆ halos alone cannot account for all the observed W…
Herschel Optimized Tau and Temperature (HOTT) Maps: Uncertainty Analysis and Robust Parameter Extraction
Singh, Ayushi; Martin, Peter G.
We introduce the HOTT dust optical depth and temperature maps parameterizing thermal dust emission. Such maps have revolutionized studies of the distribution of matter in molecular clouds and processes relevant to star formation, including virial stability. HOTT maps for a suite of fields, including the Herschel Gould Belt Survey, are available on…
The North/South Asymmetry of the Galaxy: Possible Connection to the Vertical Phase-space Snail
Mao, Shude; Liu, Chao; Shen, Juntai +2 more
The galaxy is found to be in disequilibrium based on recent findings of the north/south (N/S) asymmetry and the phase mixing signatures, such as a phase spiral (snail) structure in the vertical phase space (z - V z ). We show that the N/S asymmetry in a tracer population of dwarfs may be quantitatively modeled with a simple phase snail…
The Solar Cycle Temporal Variation of the Solar Wind Charge Exchange X-Ray Lines
Kaaret, Philip; Bregman, Joel N.; Qu, Zhijie +2 more
Solar wind charge exchange (SWCX) is the primary contamination of soft X-ray emission lines from the Milky Way (MW) hot gas. We report a solar cycle (≈10 yr) temporal variation of observed O VII and O VIII emission line measurements in the XMM-Newton archive, which is tightly correlated with the solar cycle traced by the sunspot number (SSN). This…
Stumbling over Planetary Building Blocks: AU Microscopii as an Example of the Challenge of Retrieving Debris-disk Dust Properties
Weinberger, Alycia J.; Arnold, Jessica A.; Videen, Gorden +1 more
We explore whether assumptions about dust grain shape affect the resulting estimates of the composition and grain size distribution of the AU Microscopii (AU Mic) debris disk from scattered-light data collected by Lomax et al. The near edge-on orientation of the AU Mic debris disk makes it ideal for studying the effect of the scattering phase func…
The Baltimore Oriole's Nest: Cool Winds from the Inner and Outer Parts of a Star-forming Galaxy at z = 1.3
Barro, Guillermo; Weiner, Benjamin J.; Pacifici, Camilla +12 more
Strong galactic winds are ubiquitous at z ≳ 1. However, it is not well-known where inside galaxies these winds are launched from. We study the cool winds (~104 K) in two spatial regions of a massive galaxy at z = 1.3, which we nickname the "Baltimore Oriole's Nest." The galaxy has a stellar mass of 1010.3±0.3 M ⊙, …
The Coupling of an EUV Coronal Wave and Ion Acceleration in a Fermi-LAT Behind-the-Limb Solar Flare
Krucker, Säm; Veronig, Astrid M.; Warmuth, Alexander +6 more
We present the Fermi-LAT observations of the behind-the-limb (BTL) flare of 2021 July 17 and the joint detection of this flare by STIX on board the Solar Orbiter. The separation between Earth and the Solar Orbiter was 99.°2 at 05:00 UT, allowing STIX to have a front view of the flare. The location of the flare was S20E140 in Stonyhurst heliographi…
A Census of Above-horizontal-branch Stars in Galactic Globular Clusters
Bond, Howard E.; Ciardullo, Robin; Siegel, Michael H. +1 more
We have carried out a search for above-horizontal-branch (AHB) stars-objects lying above the horizontal branch (HB) and blueward of the asymptotic giant branch (AGB) in the color-magnitude diagram-in 97 Galactic and seven Magellanic Cloud globular clusters (GCs). We selected AHB candidates based on photometry in the uBVI system, which is optimized…
On the Origin of the Photospheric Magnetic Field
Linton, Mark G.; Schuck, Peter W.; Knizhnik, Kalman J. +1 more
This article presents results that challenge the paradigms that (1) the convection zone is the source of the radial magnetic field in the photosphere and (2) that coronal currents are neutralized from the perspective of the photosphere. We demonstrate, using a new analysis tool applied to simulations and observations, that bare or partially dresse…
Consistent Analysis of the AGN LF in X-Ray and MIR in the XMM-LSS Field
Clements, D. L.; Brandt, W. N.; Nyland, Kristina +9 more
The luminosity function of active galactic nuclei (AGN) probes the history of supermassive black hole assembly and growth across cosmic time. To mitigate selection biases, we present a consistent analysis of the AGN luminosity functions (LFs) derived for both X-ray and mid-infrared (MIR) selected AGN in the XMM-Large Scale Structure field. There a…