Search Publications
Young Stars and Ionized Nebulae in M83: Comparing Chemical Abundances at High Metallicity.
Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A. +3 more
We present spectra of 14 A-type supergiants in the metal-rich spiral galaxy M83. We derive stellar parameters and metallicities and measure a spectroscopic distance modulus µ =28.47+/- 0.10 (4.9 ± 0.2 Mpc), in agreement with other methods. We use the stellar characteristic metallicity of M83 and other systems to discuss a version of the gala…
First Results from the MADCASH Survey: A Faint Dwarf Galaxy Companion to the Low-mass Spiral Galaxy NGC 2403 at 3.2 Mpc
Bell, Eric F.; Forbes, Duncan A.; Romanowsky, Aaron J. +13 more
We report the discovery of the faintest known dwarf galaxy satellite of a Large Magellanic Cloud (LMC) stellar-mass host beyond the Local Group (LG), based on deep imaging with Subaru/Hyper Suprime-Cam. Magellanic Analog Dwarf Companions And Stellar Halos (MADCASH) J074238+652501-dw lies ∼35 kpc in projection from NGC 2403, a dwarf spiral galaxy a…
A Deep Search for Faint Galaxies Associated with Very Low Redshift C IV Absorbers. III. The Mass- and Environment-dependent Circumgalactic Medium
Tripp, Todd M.; Prochaska, J. Xavier; Tumlinson, Jason +6 more
Using Hubble Space Telescope Cosmic Origins Spectrograph observations of 89 QSO sightlines through the Sloan Digital Sky Survey footprint, we study the relationships between C IV absorption systems and the properties of nearby galaxies, as well as the large-scale environment. To maintain sensitivity to very faint galaxies, we restrict our sample t…
BICEP2/Keck Array VIII: Measurement of Gravitational Lensing from Large-scale B-mode Polarization
Ade, P. A. R.; Bock, J. J.; Crill, B. P. +62 more
We present measurements of polarization lensing using the 150 GHz maps, which include all data taken by the BICEP2 and Keck Array Cosmic Microwave Background polarization experiments up to and including the 2014 observing season (BK14). Despite their modest angular resolution (∼ 0.5°), the excellent sensitivity (∼3µK-arcmin) of these maps ma…
The Impact of Non-uniform Thermal Structure on the Interpretation of Exoplanet Emission Spectra
Fortney, Jonathan J.; Stevenson, Kevin B.; Bean, Jacob +4 more
The determination of atmospheric structure and molecular abundances of planetary atmospheres via spectroscopy involves direct comparisons between models and data. While varying in sophistication, most model spectra comparisons fundamentally assume one-dimensional (1D) model physics. However, knowledge from general circulation models and of solar s…
The Nuclear Cluster of the Milky Way: Total Mass and Luminosity
Genzel, R.; Gillessen, S.; Eisenhauer, F. +6 more
We obtain the basic properties of the nuclear cluster of the Milky Way. First, we investigate the structural properties by constructing a stellar density map of the central 1000″ using extinction-corrected old star counts from VISTA, WFC3/IR, and VLT/NACO data. We describe the data using two components. The inner, slightly flattened (axis ratio of…
Predicting Coronal Mass Ejections Using Machine Learning Methods
Ilonidis, S.; Bobra, M. G.
Of all the activity observed on the Sun, two of the most energetic events are flares and coronal mass ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true. Despite advances in numerical modeling, it is still unclear which circumstances will produce a CME. Therefore, it is wo…
Compressive Coherent Structures at Ion Scales in the Slow Solar Wind
Maksimovic, M.; Alexandrova, O.; Kasper, J. C. +5 more
We present a study of magnetic field fluctuations in a slow solar wind stream, close to ion scales, where an increase of the level of magnetic compressibility is observed. Here, the nature of these compressive fluctuations is found to be characterized by coherent structures. Although previous studies have shown that current sheets can be considere…
The Most Luminous Heavily Obscured Quasars Have a High Merger Fraction: Morphological Study of WISE-selected Hot Dust-obscured Galaxies
Fang, Guanwen; Yang, Jun; Fan, Lulu +6 more
Previous studies have shown that Wide-field Infrared Survey Explorer-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly Compton-thick active galactic nuclei (AGNs). High obscuration provides us a good chance to study the host morphology of the most luminous AGNs directly. We analyze the host…
MOST Observations of Our Nearest Neighbor: Flares on Proxima Centauri
Davenport, James R. A.; Sasselov, Dimitar; Kipping, David M. +2 more
We present a study of white-light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite Microvariability and Oscillations of STars. Using 37.6 days of monitoring data from 2014 to 2015, we have detected 66 individual flare events, the largest number of white-light flares observed to date on Proxima Cen. Flare energie…