Search Publications
On the Origin of Inner Coma Structures Observed by Rosetta during a Diurnal Rotation of Comet 67P/Churyumov--Gerasimenko.
Kramer, Tobias; Noack, Matthias
The Rosetta probe around comet 67P/Churyumov-Gerasimenko (67P) reveals an anisotropic dust distribution of the inner coma with jet-like structures. The physical processes leading to jet formation are under debate, with most models for cometary activity focusing on localized emission sources, such as cliffs or terraced regions. Here we suggest, by …
Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters. I. Statistical and Computational Methods
Stenning, D. C.; Wagner-Kaiser, R.; Robinson, E. +4 more
We develop a Bayesian model for globular clusters composed of multiple stellar populations, extending earlier statistical models for open clusters composed of simple (single) stellar populations. Specifically, we model globular clusters with two populations that differ in helium abundance. Our model assumes a hierarchical structuring of the parame…
Weighing Stars: The Identification of an Evolved Blue Straggler Star in the Globular Cluster 47 Tucanae
Dalessandro, E.; Massari, D.; Mucciarelli, A. +4 more
Globular clusters are known to host peculiar objects named blue straggler stars (BSSs), significantly heavier than the normal stellar population. While these stars can be easily identified during their core hydrogen-burning phase, they are photometrically indistinguishable from their low-mass sisters in advanced stages of the subsequent evolution.…
Simulations of Alfvén and Kink Wave Driving of the Solar Chromosphere: Efficient Heating and Spicule Launching
Arber, T. D.; Brady, C. S.
Two of the central problems in our understanding of the solar chromosphere are how the upper chromosphere is heated and what drives spicules. Estimates of the required chromospheric heating, based on radiative and conductive losses, suggest a rate of ∼0.1 erg cm-3 s-1 in the lower chromosphere and drops to ∼10-3 er…
The Gigaelectronvolt Counterpart of VER J2019+407 in the Northern Shell of the Supernova Remnant G78.2+2.1 (γ Cygni)
Fraija, N.; Araya, M.
Analysis of gamma-ray emission from the supernova remnant G78.2+2.1 (γ Cygni) with 7.2 years of cumulative data from the Fermi Large Area Telescope shows a distinct hard, bright, and extended component to the north of the shell coincident with the known teraelectronvolt source VER J2019+407. In the gigaelectronvolt to teraelectronvolt (GeV-TeV) en…
Merging Galaxies with Tidal Tails in COSMOS to z = 1
Zheng, Xian Zhong; Wen, Zhang Zheng
Tidal tails are created in major mergers involving disk galaxies. It remains to be explored how the tidal tails trace the assembly history of massive galaxies. We identify a sample of 461 merging galaxies with long tidal tails, from 35,076 galaxies mass-complete at {M}\star ≥slant {10}9.5 {M}⊙ and 0.2≤slant z≤slan…
The Detection and Statistics of Giant Arcs behind CLASH Clusters
Zheng, Wei; Zitrin, Adi; Frye, Brenda +10 more
We developed an algorithm to find and characterize gravitationally lensed galaxies (arcs) to perform a comparison of the observed and simulated arc abundance. Observations are from the Cluster Lensing And Supernova survey with Hubble (CLASH). Simulated CLASH images are created using the MOKA package and also clusters selected from the high-resolut…
Mapping CO Gas in the GG Tauri A Triple System with 50 au Spatial Resolution
Tang, Ya-Wen; Dutrey, Anne; Di Folco, Emmanuel +11 more
We aim to unveil the observational imprint of physical mechanisms that govern planetary formation in the young, multiple system GG Tau A. We present ALMA observations of 12CO and 13CO 3-2 and 0.9 mm continuum emission with 0.″35 resolution. The 12CO 3-2 emission, found within the cavity of the circumternary dust ri…
A Search for Hyperluminous X-Ray Sources in the XMM-Newton Source Catalog
Bachetti, M.; Godet, O.; Webb, N. A. +2 more
We present a new method to identify luminous off-nuclear X-ray sources in the outskirts of galaxies from large public redshift surveys, distinguishing them from foreground and background interlopers. Using the 3XMM-DR5 catalog of X-ray sources and the SDSS DR12 spectroscopic sample of galaxies, with the help of this off-nuclear cross-matching tech…
Chandra X-Ray and Hubble Space Telescope Imaging of Optically Selected Kiloparsec-scale Binary Active Galactic Nuclei. II. Host Galaxy Morphology and AGN Activity
Shen, Yue; Ho, Luis C.; Strauss, Michael A. +4 more
Binary active galactic nuclei (AGNs) provide clues to how gas-rich mergers trigger and fuel AGNs and how supermassive black hole (SMBH) pairs evolve in a gas-rich environment. While significant effort has been invested in their identification, the detailed properties of binary AGNs and their host galaxies are still poorly constrained. In a compani…