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DUSTiNGS. III. Distribution of Intermediate-age and Old Stellar Populations in Disks and Outer Extremities of Dwarf Galaxies
McQuinn, Kristen B. W.; Skillman, Evan D.; Boyer, Martha L. +8 more
We have traced the spatial distributions of intermediate-age and old stars in nine dwarf galaxies in the distant parts of the Local Group, using multi-epoch 3.6 and 4.5 µm data from the DUST in Nearby Galaxies with Spitzer (DUSTiNGS) survey. Using complementary optical imaging from the Hubble Space Telescope, we identify the tip of the red g…
Spectral properties of Martian and other planetary glasses and their detection in remotely sensed data
Mustard, John F.; Dyar, M. Darby; Cannon, Kevin M. +3 more
Thirty silicate glasses were synthesized as realistic analogs to those expected to exist on Mars, the Moon, and Mercury. Samples were measured using visible/near-infrared and Mössbauer spectroscopy to determine the effects of varying bulk chemistry, oxygen fugacity, and temperature on spectral properties. For Martian glasses, the fO2 du…
Size and Shape of Chariklo from Multi-epoch Stellar Occultations
Colas, F.; Bérard, D.; Lellouch, E. +28 more
We use data from five stellar occultations observed between 2013 and 2016 to constrain Chariklo’s size and shape, and the ring reflectivity. We consider four possible models for Chariklo (sphere, Maclaurin spheroid, triaxial ellipsoid, and Jacobi ellipsoid), and we use a Bayesian approach to estimate the corresponding parameters. The spherical mod…
Astrometry with Hubble Space Telescope Fine Guidance Sensors—A Review
Nelan, Edmund P.; Harrison, Thomas E.; Benedict, G. Fritz +1 more
Over the last 20 years, Hubble Space Telescope Fine Guidance Sensor interferometric astrometry has produced precise and accurate parallaxes of astrophysical interesting stars and mass estimates for stellar companions. We review parallax results, and binary star and exoplanet mass determinations, and compare a subset of these parallaxes with prelim…
An infrared view of AGN feedback in a type-2 quasar: the case of the Teacup galaxy
Villar-Martín, M.; Ramos Almeida, C.; Piqueras López, J. +1 more
We present near-infrared integral field spectroscopy data obtained with Very Large Telescope/Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) of 'the Teacup galaxy'. The nuclear K-band (1.95-2.45 µm) spectrum of this radio-quiet type-2 quasar reveals a blueshifted broad component of FWHM ∼ 1600-1800 km s-1
Radio Pulse Search and X-Ray Monitoring of SAX J1808.4-3658: What Causes Its Orbital Evolution?
Hessels, Jason W. T.; Wijnands, Rudy; van der Klis, Michiel +6 more
The accreting millisecond X-ray pulsar SAX J1808.4-3658 shows a peculiar orbital evolution that proceeds at a very fast pace. It is important to identify the underlying mechanism responsible for this behavior because it can help to understand how this system evolves and which physical processes (such as mass loss or spin-orbit coupling) are occurr…
Observational Evidence of Magnetic Reconnection for Brightenings and Transition Region Arcades in IRIS Observations
Feng, Li; Zhu, Xiaoshuai; Li, Hui +4 more
By using a new method of forced-field extrapolation, we study the emerging flux region AR11850 observed by the Interface Region Imaging Spectrograph and Solar Dynamical Observatory. Our results suggest that the bright points (BPs) in this emerging region exhibit responses in lines formed from the upper photosphere to the transition region, which h…
Imaging a Central Ionized Component, a Narrow Ring, and the CO Snowline in the Multigapped Disk of HD 169142
Carrasco-González, Carlos; Rodríguez, Luis F.; Macías, Enrique +5 more
We report Very Large Array observations at 7 mm, 9 mm, and 3 cm toward the pre-transitional disk of the Herbig Ae star HD 169142. These observations have allowed us to study the millimeter emission of this disk with the highest angular resolution so far (0.″12 × 0.″09, or 14 au × 11 au, at 7 mm). Our 7 and 9 mm images show a narrow ring of emissio…
Constraining the dark energy equation of state using Bayes theorem and the Kullback-Leibler divergence
Hobson, M. P.; Lasenby, A. N.; Hee, S. +2 more
Data-driven model-independent reconstructions of the dark energy equation of state w(z) are presented using Planck 2015 era cosmic microwave background, baryonic acoustic oscillations (BAO), Type Ia supernova (SNIa) and Lyman α (Lyα) data. These reconstructions identify the w(z) behaviour supported by the data and show a bifurcation of the equatio…
Precise surface gravities of δ Scuti stars from asteroseismology
Reese, D. R.; Garrido, R.; Martín-Ruiz, S. +8 more
The work reported here demonstrates that it is possible to accurately determine surface gravities of δ Scuti (δ Sct) stars using the frequency content from high-precision photometry and a measurement of the parallax. Using a sample of 10 eclipsing binary systems with a δ Sct component and the unique δ Sct star discovered with a transiting planet, …