Search Publications
A Comparison of Flare Forecasting Methods. II. Benchmarks, Metrics, and Performance Results for Operational Solar Flare Forecasting Systems
Leka, K. D.; Gallagher, Peter T.; Murray, Sophie A. +21 more
Solar flares are extremely energetic phenomena in our solar system. Their impulsive and often drastic radiative increases, particularly at short wavelengths, bring immediate impacts that motivate solar physics and space weather research to understand solar flares to the point of being able to forecast them. As data and algorithms improve dramatica…
The 3HSP catalogue of extreme and high-synchrotron peaked blazars
Giommi, P.; Padovani, P.; Chang, Y. -L. +2 more
Aims: High-synchrotron peaked blazars (HSPs or HBLs) play a central role in very high-energy (VHE) γ-ray astronomy, and likely in neutrino astronomy. Currently, the largest compilation of HSP blazars, the 2WHSP sample, includes 1691 sources, but it is not complete in the radio or in the X-ray band. In order to provide a larger and more accura…
Tidal Interactions between Binary Stars Can Drive Lithium Production in Low-mass Red Giants
Hogg, David W.; Casey, Andrew R.; Rix, Hans-Walter +10 more
Theoretical models of stellar evolution predict that most of the lithium inside a star is destroyed as the star becomes a red giant. However, observations reveal that about 1% of red giants are peculiarly rich in lithium, often exceeding the amount in the interstellar medium or predicted from the big bang. With only about 150 lithium-rich giants d…
A Mass-dependent Slope of the Galaxy Size-Mass Relation out to z ∼ 3: Further Evidence for a Direct Relation between Median Galaxy Size and Median Halo Mass
Mowla, Lamiya; van Dokkum, Pieter; van der Wel, Arjen +1 more
We reassess the galaxy size-mass relation out to z ∼ 3 using a new definition of size and a sample of >29,000 galaxies from the 3D-HST, CANDELS, and COSMOS-DASH surveys. Instead of the half-light radius r 50 we use r 80, the radius containing 80% of the stellar light. We find that the r 80-M * relatio…
High Angular Resolution ALMA Images of Dust and Molecules in the SN 1987A Ejecta
Bouchet, P.; Wheeler, J. C.; Matsuura, Mikako +23 more
We present high angular resolution (∼80 mas) ALMA continuum images of the SN 1987A system, together with CO J = 2 \to 1, J = 6 \to 5, and SiO J = 5 \to 4 to J = 7 \to 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the du…
Element Abundances: A New Diagnostic for the Solar Wind
Vourlidas, Angelos; Cranmer, Steven R.; Wood, Brian E. +11 more
We examine the different element abundances exhibited by the closed loop solar corona and the slow speed solar wind. Both are subject to the first ionization potential (FIP) effect, the enhancement in coronal abundance of elements with FIP below 10 eV (e.g., Mg, Si, Fe) with respect to high-FIP elements (e.g., O, Ne, Ar), but with subtle differenc…
Discovery of Tidal Tails in Disrupting Open Clusters: Coma Berenices and a Neighbor Stellar Group
Lin, Chien-Cheng; Tang, Shih-Yun; Chen, W. P. +6 more
We report the discovery of tidal structures around the intermediate-aged (∼700-800 Myr), nearby (∼85 pc) star cluster Coma Berenices. The spatial and kinematic grouping of stars is determined with the Gaia DR2 parallax and proper motion data, by a clustering analysis tool, STARGO, to map 5D parameters (X, Y, Z, {µ }α \cos δ ,{&mic…
Gaia DR2 in 6D: searching for the fastest stars in the Galaxy
Rossi, E. M.; Brown, A. G. A.; Marchetti, T.
We search for the fastest stars in the subset of stars with radial velocity measurements of the second data release (DR2) of the European Space Agency mission Gaia. Starting from the observed positions, parallaxes, proper motions, and radial velocities, we construct the distance and total velocity distribution of more than 7 million stars in our M…
The eye of Gaia on globular clusters kinematics: internal rotation
Hilker, M.; Baumgardt, H.; Sollima, A.
We derived the three-dimensional velocities of individual stars in a sample of 62 Galactic globular clusters using proper motions from the second data release of the Gaia mission together with the most comprehensive set of line-of-sight velocities with the aim of investigating the rotation pattern of these stellar systems. We detect the unambiguou…
The Milky Way bar/bulge in proper motions: a 3D view from VIRAC and Gaia
Smith, Leigh C.; Gerhard, Ortwin; Wegg, Christopher +3 more
We have derived absolute proper motions of the entire Galactic bulge region from VVV Infrared Astrometric Catalogue (VIRAC) and Gaia. We present these both as integrated on-sky maps and, after isolating standard candle red clump (RC) stars, as a function of distance using RC magnitude as a proxy. These data provide a new global, 3D view of the Mil…