Search Publications
The Evolution of Plasma Composition during a Solar Flare
Long, David M.; Brooks, David H.; Baker, Deborah +4 more
We analyze the coronal elemental abundances during a small flare using Hinode/EIS observations. Compared to the preflare elemental abundances, we observed a strong increase in coronal abundance of Ca XIV 193.84 Å, an emission line with low first ionization potential (FIP < 10 eV), as quantified by the ratio Ca/Ar during the flare. This is in co…
The 6.2 µm PAH Feature and the Role of Nitrogen: Revisited
Boersma, C.; Peeters, E.; Ricca, A.
This study revisits the role that nitrogen inclusion in polycyclic aromatic hydrocarbons (PAHs; those with nitrogen inclusion, PANHs) plays in their infrared (IR) spectral properties. We present spectra of pure PAHs, PANHs, and protonated PANHs, computed using density functional theory and basis sets that treat polarization. We investigate trends …
A Catalog of Host Galaxies for WISE-selected AGN: Connecting Host Properties with Nuclear Activity and Identifying Contaminants
Stern, Daniel; Comerford, Julia M.; Barrows, R. Scott +1 more
We present a catalog of physical properties for galaxies hosting active galactic nuclei (AGN) detected by the Wide-field Infrared Survey Explorer (WISE). By fitting broadband spectral energy distributions of sources in the WISE AGN Catalog with empirical galaxy and AGN templates, we derive photometric redshifts, AGN bolometric luminosities, measur…
Measuring the Magnetic Origins of Solar Flares, Coronal Mass Ejections, and Space Weather
Rempel, Matthias; de Toma, Giuliana; Ezzeddine, Rana +12 more
We take a broad look at the problem of identifying the magnetic solar causes of space weather. With the lackluster performance of extrapolations based upon magnetic field measurements in the photosphere, we identify a region in the near-UV (NUV) part of the spectrum as optimal for studying the development of magnetic free energy over active region…
Primordial Black Holes Formation and Secondary Gravitational Waves in Nonminimal Derivative Coupling Inflation
Karami, Kayoomars; Teimoori, Zeinab; Rezazadeh, Kazem
We study the possibility of the primordial black holes (PBHs) formation with the aim of finding a considerable fraction of dark matter (DM), using the gravitationally enhanced friction mechanism which arises from a nonminimal derivative coupling between the scalar field and the gravity. Assuming the nonminimal coupling parameter as a special funct…
Far-UV and Optical Emissions from Three Very Large Supernova Remnants Located at Unusually High Galactic Latitudes
Raymond, John C.; Milisavljevic, Dan; Fesen, Robert A. +9 more
Galactic supernova remnants (SNRs) with angular dimensions greater than a few degrees are relatively rare, as are remnants located more than 10° off the Galactic plane. Here we report a UV and optical investigation of two previously suspected SNRs more than 10° in both angular diameter and Galactic latitude. One is a proposed remnant discovered in…
Ubiquitous [O II] Emission in Quiescent Galaxies at z ≈ 0.85 from the LEGA-C Survey
Bell, Eric F.; Maseda, Michael V.; D'Eugenio, Francesco +12 more
Using deep rest-frame optical spectroscopy from the Large Early Galaxy Astrophysical Census (LEGA-C) survey, conducted using VIMOS on the ESO Very Large Telescope, we search for low-ionization [O II] λ λ 3726,3729 emission in the spectra of a mass-complete sample of z ≈ 0.85 galaxies. We find that 59% of UVJ-quiescent (i.e., non-star-forming) gala…
Stellar Dynamical Models for 797 z 0.8 Galaxies from LEGA-C
Bell, Eric F.; Maseda, Michael V.; Franx, Marijn +12 more
We present spatially resolved stellar kinematics for 797 z = 0.6-1 galaxies selected from the LEGA-C survey and construct axisymmetric Jeans models to quantify their dynamical mass and degree of rotational support. The survey is K s -band selected, irrespective of color or morphological type, and allows for a first assessment of the st…
Extreme r-process Enhanced Stars at High Metallicity in Fornax
Hansen, C. J.; Reichert, M.; Arcones, A.
We present and discuss three extremely r-process enhanced stars located in the massive dwarf spheroidal galaxy Fornax. These stars are very unique with an extreme Eu enrichment (1.25 ≤ [Eu/Fe]≤1.45) at high metallicities (-1.3 ≤ [Fe/H]≤-0.8). They have the largest Eu abundances ever observed in a dwarf galaxy opening new opportunities to further u…
AGN Triality of Triple Mergers: Detection of Faint X-Ray Point Sources
Gültekin, Kayhan; Runnoe, Jessie C.; Foord, Adi +1 more
We present results from our X-ray analysis of a systematic search for triple active galactic nuclei (AGNs) in nearby (z < 0.077) triple galaxy mergers. We analyze archival Chandra observations of seven triple galaxy mergers with BAYMAX (Bayesian Analysis of Multiple AGNs in X-rays), fitting each observation with single, dual, and triple X-ray p…