Search Publications
Combined Scattering of Radiation Belt Electrons Caused by Landau and Bounce Resonant Interactions With Magnetosonic Waves
Fu, Song; Ni, Binbin; Gu, Xudong +2 more
We develop a full relativistic test particle code to model the combined electron scattering effect of Landau and bounce resonances with magnetosonic waves. Test particle simulations of magnetosonic wave-electron interactions indicate that the two resonances coexist to affect radiation belt electrons at different energies and pitch angles, and the …
Reverberation Mapping of the Narrow-line Seyfert 1 Galaxy I Zwicky 1: Black Hole Mass
Ho, Luis C.; Bian, Wei-Hao; Zhang, Zhi-Xiang +11 more
We report results of the first reverberation mapping campaign of I Zwicky 1 during 2014-2016, which showed unambiguous reverberations of the broad Hβ line emission in the varying optical continuum. From analysis using several methods, we obtain a reverberation lag of {τ }{{H}β }={37.2}-4.9+4.5 {days}. Taking a viri…
CO Detected in CI Tau b: Hot Start Implied by Planet Mass and M K
Johns-Krull, Christopher M.; Prato, L.; Flagg, Laura +5 more
We acquired high-resolution infrared spectra of CI Tau, the host star of one of the few young planet candidates amenable to direct spectroscopic detection. We confirm the planet’s existence with a direct detection of CO in the planet’s atmosphere. We also calculate a mass of 11.6 M J based on the amplitude of its radial velocity variati…
Direct evidence of nonstationary collisionless shocks in space plasmas
Pulkkinen, Tuija I.; Russell, Christopher T.; Dandouras, Iannis +11 more
Distances and ages from isochrone fits of 150 open clusters using Gaia DR2 data
Dias, W. S.; Monteiro, H.
We investigate a sample of open cluster candidates with no previous age determination using astrometric and photometric data from the Gaia DR2 catalogue. Using proper motions and parallaxes and the full co-variance matrix we determined the astrometric membership probability of the stars in the field of each candidate. The memberships were used as …
16O/18O ratio in water in the coma of comet 67P/Churyumov-Gerasimenko measured with the Rosetta/ROSINA double-focusing mass spectrometer
De Keyser, Johan; Gombosi, Tamas I.; Berthelier, Jean-Jacques +11 more
The European Space Agency spacecraft Rosetta accompanied the Jupiter-family comet 67P/Churyumov-Gerasimenko for over 2 yr along its trajectory through the inner solar system. Between 2014 and 2016, it performed almost continuous in situ measurements of the comet's gaseous atmosphere in close proximity to its nucleus. In this study, the 16
AGN feedback and multiphase gas in giant elliptical galaxies
Ruszkowski, Mateusz; Li, Yuan; Wang, Chaoran
Recent observations have found extended multiphase gas in a significant fraction of massive elliptical galaxies. We perform high-resolution three-dimensional hydrodynamical simulations of two idealized elliptical galaxies - one representing a typical galaxy characterized by initial conditions conducive to the development of thermal instability and…
Evidence for spots on hot stars suggests major revision of stellar physics
Balona, L. A.
It has long been thought that starspots are not present in the A and B stars because magnetic fields cannot be generated in stars with radiative envelopes. Space observations show that a considerable fraction of these stars varies in light with periods consistent with the expected rotation periods. Here we show that the photometric periods are the…
Multiple Rings of Millimeter Dust Emission in the HD 15115 Debris Disk
MacGregor, Meredith A.; Weinberger, Alycia J.; Nesvold, Erika R. +8 more
We present observations of the HD 15115 debris disk from the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.3 mm that capture this intriguing system with the highest resolution (0.″6 or 29 au) at millimeter wavelengths to date. This new ALMA image shows evidence for two rings in the disk separated by a cleared gap. By fitting models dire…
High Gas Fraction in a CO-detected Main-sequence Galaxy at z > 3
Daddi, Emanuele; Neri, Roberto; Dannerbauer, Helmut +3 more
We report NOrthern Extended Millimetre Array (NOEMA) observations of warm molecular gas traced by CO(5 - 4) in a z∼ 3.2 gas-rich main-sequence (MS) galaxy, initially serendipitously detected in CO(3 - 2) emission in “blind” deep NOEMA observations. Our target shows a gas excitation consistent with that seen in z∼ 1.5 MS galaxies ({L}CO(…