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A Blue Point Source at the Location of Supernova 2011dh
Van Dyk, Schuyler D.; Nomoto, Ken'ichi; Quimby, Robert M. +7 more
We present Hubble Space Telescope (HST) observations of the field of the Type IIb supernova (SN) 2011dh in M51 performed at ≈1161 rest-frame days after explosion using the Wide Field Camera 3 and near-UV filters F225W and F336W. A star-like object is detected in both bands and the photometry indicates it has negative (F225W - F336W) color. The obs…
JKCS 041: a Coma cluster progenitor at z = 1.803
Andreon, S.; Treu, T.; Newman, A. B. +3 more
Using deep two-color near-infrared HST imaging and unbiased grism spectroscopy, we present a detailed study of the z = 1.803 JKCS 041 cluster. We confirm, for the first time for a high-redshift cluster, a mass of log M ≳ 14.2 in solar units using four different techniques based on the X-ray temperature, the X-ray luminosity, the gas mass, and the …
Empirical tests of pre-main-sequence stellar evolution models with eclipsing binaries
Torres, Guillermo; Stassun, Keivan G.; Feiden, Gregory A.
We examine the performance of standard pre-main-sequence (PMS) stellar evolution models against the accurately measured properties of a benchmark sample of 26 PMS stars in 13 eclipsing binary (EB) systems having masses 0.04-4.0 M⊙ and nominal ages ≈1-20 Myr. We provide a definitive compilation of all fundamental properties for the EBs, …
Chemical composition of Titan’s atmosphere and ionosphere: Observations and the photochemical model
Krasnopolsky, Vladimir A.
Basic observational data on hydrocarbons, nitriles, and ions on Titan are compared with predictions of the photochemical model. Uncertainties of the observed abundances and differences between the data from different instruments and observing teams are comparable with the differences between the observations and the model results. Main reactions o…
Galaxy Zoo: CANDELS barred discs and bar fractions
Finkelstein, Steven L.; Bell, Eric F.; Ferguson, Henry C. +39 more
The formation of bars in disc galaxies is a tracer of the dynamical maturity of the population. Previous studies have found that the incidence of bars in discs decreases from the local Universe to z ∼ 1, and by z > 1 simulations predict that bar features in dynamically mature discs should be extremely rare. Here, we report the discovery of stro…
Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
Sneden, C.; Wood, M. P.; Lawler, J. E. +1 more
Atomic transition probability measurements for 371 Ni I lines in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer and a new echelle spectrograph are combined with published radiative lifetimes to determine these transition probabilities. Generally good agreement is found in comparis…
Current status of CME/shock arrival time prediction
Dryer, Murray; Zhao, Xinhua
One of the major solar transients, coronal mass ejections (CMEs) and their related interplanetary shocks have severe space weather effects and become the focus of study for both solar and space scientists. Predicting their evolutions in the heliosphere and arrival times at Earth is an important component of the space weather predictions. Various k…
Resolved Imaging of the HR 8799 Debris Disk with Herschel
Macintosh, Bruce; Matthews, Brenda; Marois, Christian +5 more
We present Herschel far-infrared and submillimeter maps of the debris disk associated with the HR 8799 planetary system. We resolve the outer disk emission at 70, 100, 160, and 250 µm and detect the disk at 350 and 500 µm. A smooth model explains the observed disk emission well. We observe no obvious clumps or asymmetries associated wi…
Ceci N'est Pas a Globular Cluster: The Metallicity Distribution of the Stellar System Terzan 5
Dalessandro, E.; Massari, D.; Valenti, E. +9 more
We present new determinations of the iron abundance for 220 stars belonging to the stellar system Terzan 5 in the Galactic bulge. The spectra have been acquired with FLAMES at the Very Large Telescope of the European Southern Observatory and DEIMOS at the Keck II Telescope. This is by far the largest spectroscopic sample of stars ever observed in …
Astrometric detection of giant planets around nearby M dwarfs: the Gaia potential
Sozzetti, A.; Giacobbe, P.; Lattanzi, M. G. +3 more
Cool M dwarfs within a few tens of parsecs from the Sun are becoming the focus of dedicated observational programs in the realm of exoplanet astrophysics. Gaia, in its all-sky survey of >109 objects, will deliver precision astrometry for a magnitude-limited (V = 20) sample of M dwarfs. We investigate some aspects of the synergy betwe…