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Reverberation reveals the truncated disc in the hard state of GX 339-4
Done, Chris; Mahmoud, Ra'ad D.; De Marco, Barbara
The nature and geometry of the hard state in black hole binaries is controversial. The broad-band continuum spectrum and fast variability properties can be explained in a model where the inner disc evaporates into a geometrically thick, hot flow. However, these models are challenged by the persistent detection of an extremely broad iron line, whic…
A Family Picture: Tracing the Dynamical Path of the Structural Properties of Multiple Populations in Globular Clusters
Dalessandro, Emanuele; Martocchia, S.; Bastian, N. +6 more
We studied the spatial distributions of multiple stellar populations (MPs) in a sample of 20 globular clusters (GCs) spanning a broad range of dynamical ages. The differences between first-population (FP) and second-population (SP) stars were measured by means of the parameter A +, defined as the area enclosed between their cumulative r…
A census of massive stars in NGC 346. Stellar parameters and rotational velocities
Dufton, P. L.; Lennon, D. J.; Evans, C. J. +2 more
Spectroscopy for 247 stars towards the young cluster NGC 346 in the Small Magellanic Cloud has been combined with that for 116 targets from the VLT-FLAMES Survey of Massive Stars. Spectral classification yields a sample of 47 O-type and 287 B-type spectra, while radial-velocity variations and/or spectral multiplicity have been used to identify 45 …
First Detection of Plasmoids from Breakout Reconnection on the Sun
Antiochos, Spiro K.; Kumar, Pankaj; DeVore, C. Richard +2 more
Transient collimated plasma ejections (jets) occur frequently throughout the solar corona, in active regions, quiet Sun, and coronal holes. Although magnetic reconnection is generally agreed to be the mechanism of energy release in jets, the factors that dictate the location and rate of reconnection remain unclear. Our previous studies demonstrate…
Systematic serendipity: a test of unsupervised machine learning as a method for anomaly detection
Giles, Daniel; Walkowicz, Lucianne
Advances in astronomy are often driven by serendipitous discoveries. As survey astronomy continues to grow, the size and complexity of astronomical data bases will increase, and the ability of astronomers to manually scour data and make such discoveries decreases. In this work, we introduce a machine learning-based method to identify anomalies in …
The first maps of κd - the dust mass absorption coefficient - in nearby galaxies, with DustPedia
Bianchi, S.; Madden, S. C.; Galliano, F. +17 more
The dust mass absorption coefficient, κd is the conversion function used to infer physical dust masses from observations of dust emission. However, it is notoriously poorly constrained, and it is highly uncertain how it varies, either between or within galaxies. Here we present the results of a proof-of-concept study, using the DustPedi…
Col-OSSOS: The Colors of the Outer Solar System Origins Survey
Wang, Shiang-Yu; Marsset, Michaël; Fraser, Wesley C. +15 more
The Colours of the Outer Solar System Origins Survey is acquiring near-simultaneous g, r, and J photometry of unprecedented precision with the Gemini North Telescope, targeting nearly 100 trans-Neptunian objects (TNOs) brighter than m r = 23.6 mag discovered in the Outer Solar System Origins Survey. Combining the optical and near-infr…
A Precision Measurement of the Mass of the Black Hole in NGC 3258 from High-resolution ALMA Observations of Its Circumnuclear Disk
Ho, Luis C.; Barth, Aaron J.; Buote, David A. +4 more
We present ∼0.″10 resolution Atacama Large Millimeter/submillimeter Array (ALMA) CO(2-1) imaging of the arcsecond-scale (r ≈ 150 pc) dusty molecular disk in the giant elliptical galaxy NGC 3258. The data provide unprecedented resolution of the cold gas disk kinematics within the dynamical sphere of influence of a supermassive black hole (BH), reve…
Search for stellar companions of exoplanet host stars by exploring the second ESA-Gaia data release
Mugrauer, M.
A new survey is presented, which explores the second data release of the ESA-Gaia mission, in order to search for stellar companions of exoplanet host stars, located at distances closer than about 500 pc around the Sun. In total, 176 binaries, 27 hierarchical triples, and one hierarchical quadruple system are detected among more than 1300 exoplane…
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XVIII. Proper-motion Kinematics of Multiple Stellar Populations in the Core Regions of NGC 6352
Vesperini, Enrico; Anderson, Jay; van der Marel, Roeland P. +5 more
We present the analysis of the radial distributions and kinematic properties of the multiple stellar populations (mPOPs) hosted in the globular cluster (GC) NGC 6352 as part of the Hubble Space Telescope “UV Legacy Survey of Galactic Globular Clusters” program. NGC 6352 is one of the few GCs for which the mPOP tagging in appropriate color-magnitud…