Search Publications
Local Starburst Conditions and Formation of GRB 980425/SN 1998bw within a Collisional Ring
Pian, E.; Bournaud, F.; Cormier, D. +9 more
We present the first spatially resolved study of molecular gas in the vicinity of a gamma-ray burst (GRB), using CO(2-1) emission-line observations with the Atacama Large Millimetre Array at ∼50 pc scales. The host galaxy of GRB 980425 contains a ring of high column density H I gas, which is likely to have formed due to a collision between the GRB…
Characterizing the Evolved Stellar Population in the Galactic Foreground. I. Bolometric Magnitudes, Spatial Distribution and Period-Luminosity Relations
Brown, Anthony G. A.; Rich, R. Michael; Stroh, Michael C. +6 more
Radio campaigns using maser stellar beacons have provided crucial information to characterize Galactic stellar populations. Currently, the Bulge Asymmetries and Dynamical Evolution (BAaDE) project is surveying infrared (IR) color-selected targets for SiO masers. This provides a sample of evolved stars that can be used to study the inner, optically…
K2-280 b - a low density warm sub-Saturn around a mildly evolved star
Cochran, William D.; Endl, Michael; Jordán, Andrés +57 more
We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = $0.35_{-0.04}^{+0.05}$ ) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has…
Rapid spectral transition of the black hole binary V404 Cygni
Motta, S. E.; Sánchez-Fernández, C.; Alfonso-Garzón, J. +2 more
During the June 2015 outburst of the black hole binary V404 Cyg, rapid changes in the X-ray brightness and spectra were common. The INTEGRAL monitoring campaign detected spectacular Eddington-limited X-ray flares, but also rapid variations at much lower flux levels. On 2015 June 21 at 20 h 50 min, the 3-10 keV JEM-X data as well as simultaneous op…
Observations of Outward-propagating and Mirroring of the Same Energetic Electrons by Wind
Zhao, L.; Li, G.; Yao, S. +1 more
We report an energetic electron event observed by the Wind spacecraft in which electrons were first detected to propagate away from the Sun, and subsequently detected to propagate back toward the Sun. Using the recently developed fractional velocity dispersion analysis (FVDA), the path lengths corresponding to these two sequential electron signals…
KMT-2016-BLG-1836Lb: A Super-Jovian Planet from a High-cadence Microlensing Field
Han, Cheongho; Lee, Chung-Uk; Zang, Weicheng +24 more
We report the discovery of a super-Jovian planet in the microlensing event KMT-2016-BLG-1836, which was found by the Korea Microlensing Telescope Network (KMTNet) high-cadence observations ( ${\rm{\Gamma }}\sim 4\,{\mathrm{hr}}^{-1}$ ). The planet-host mass ratio q ∼ 0.004. A Bayesian analysis indicates that the planetary system is composed of a s…
Comparison of Kinematics of Solar Eruptive Prominences and Spatial Distribution of the Magnetic Decay Index
Myshyakov, Ivan; Tsvetkov, Tsvetan
Theoretical studies of electric current instability explaining solar prominence eruptions show that the loss of equilibrium may develop in a case when the surrounding magnetic field decreases sufficiently rapidly with height. The magnetic decay index, a parameter indicating whether the external magnetic field has a configuration that may lead to a…
Li-rich giant stars under scrutiny: binarity, magnetic activity, and the evolutionary status after Gaia DR2
Castro, M.; da Costa, J. S.; de Almeida, L. +2 more
We present a study of the evolutionary state of a few lithium-rich giant stars based on the Gaia Data Release 2 (DR2) parallaxes and photometry. We also investigate the chromospheric activity, the presence of a surface magnetic field, and the radial velocity for our sample stars. We analysed both archive and new data. We gathered archive spectra f…
Strömgren metallicities for intermediate-age and old star clusters
Piatti, Andrés E.
We report results that show that the straightforward star cluster metallicities obtained from Strömgren vby photometry are age-dependent and need to be corrected for further use. This outcome arises from the comparison of [Fe/H] values derived from Strömgren photometry with those metallicities published in the literature for 26 Large and Small Mag…
High-velocity interstellar absorption associated with the supernova remnant W28
Ritchey, Adam M.
We present an analysis of moderately high-resolution optical spectra obtained for the sightline to CD-23 13777, an O9 supergiant that probes high-velocity interstellar gas associated with the supernova remnant W28. Absorption components at both high positive and high negative velocity are seen in the interstellar Na I D and Ca II H and K lines tow…