Search Publications
Missions
Journals
Publication Years
An Explanation of the Nightside Ionospheric Structure of Venus
Brecht, Stephen H.; Ledvina, Stephen A.
Hybrid simulations of Venus have produced nightside structure. It is believed these are the first simulations to produce the structure reported by spacecraft such as the Pioneer Venus Orbiter (PVO). The simulations reveal that the structure is created by the ▽Pe ambipolar electric field when it aligns with local IMF (interplanetary magn…
CO isotopolog line fluxes of viscously evolving disks. Cold CO conversion insufficient to explain observed low fluxes
van Dishoeck, E. F.; Rosotti, G.; Trapman, L. +2 more
Context. Protoplanetary disks are thought to evolve viscously, where the disk mass - the reservoir available for planet formation - decreases over time as material is accreted onto the central star over a viscous timescale. Observations have shown a correlation between disk mass and the stellar mass accretion rate, as expected from viscous theory.…
Polarization of hot Jupiter systems: a likely detection of stellar activity and a possible detection of planetary polarization
Bailey, Jeremy; Cotton, Daniel V.; Kedziora-Chudczer, Lucyna +6 more
We present high-precision linear polarization observations of four bright hot Jupiter systems (τ Boo, HD 179949, HD 189733, and 51 Peg) and use the data to search for polarized reflected light from the planets. The data for 51 Peg are consistent with a reflected light polarization signal at about the level expected with 2.8σ significance and a fal…
Impact of foreshock transients on the flank magnetopause and magnetosphere and the ionosphere
Wang, Chih-Ping; Wang, Xueyi; Liu, Terry Z. +1 more
Mesoscale (on the scales of a few minutes and a few RE) magnetosheath and magnetopause perturbations driven by foreshock transients have been observed in the flank magnetotail. In this paper, we present the 3D global hybrid simulation results to show qualitatively the 3D structure of the flank magnetopause distortion caused by foreshock transients…
ALMA Super-resolution Imaging of T Tau: r = 12 au Gap in the Compact Dust Disk around T Tau N
Tamura, Motohide; Yamaguchi, Masayuki; Nomura, Hideko +5 more
Based on Atacama Large Millimeter/submillimeter Array (ALMA) observations, compact protoplanetary disks with dust radii of r ≲ 20-40 au were found to be dominant in nearby low-mass star formation regions. However, their substructures have not been investigated because of the limited spatial resolution achieved so far. We apply a newly developed su…
Improved Measurements of the Sun's Meridional Flow and Torsional Oscillation from Correlation Tracking on MDI and HMI Magnetograms
Mahajan, Sushant S.; Hathaway, David H.; Muñoz-Jaramillo, Andrés +1 more
The Sun's axisymmetric flows, differential rotation, and meridional flow govern the dynamics of the solar magnetic cycle, and a variety of methods are used to measure these flows, each with its own strengths and weaknesses. Flow measurements based on cross-correlating images of the surface magnetic field have been made since the 1970s that require…
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey quasar sample: testing observational systematics on the Baryon Acoustic Oscillation measurement
Myers, Adam D.; Brownstein, Joel R.; Schneider, Donald P. +15 more
Baryon Acoustic Oscillations (BAO) are considered to be a very robust standard ruler against various systematics. This premise has been tested against observational systematics, but not to the level required for the next generation of galaxy surveys such as the Dark Energy Spectroscopic Instrument (DESI) and Euclid. In this paper, we investigate t…
Age-metallicity dependent stellar kinematics of the Milky Way disc from LAMOST and Gaia
Zhao, Gang; Wu, Yaqian; Xiang, Maosheng +5 more
We investigate the stellar kinematics of the Galactic disc in 7 < R < 13 kpc using a sample of 118 945 red giant branch (RGB) stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Gaia. We characterize the median, dispersion and skewness of the distributions of the three-dimensional stellar velocities, actions…
Tully-Fisher Distances and Dynamical Mass Constraints for 24 Host Galaxies of Reverberation-mapped AGNs
Crenshaw, D. M.; Bentz, Misty C.; Courtois, Hélène M. +6 more
We present Tully-Fisher distances for 24 active galactic nucleus (AGN) host galaxies with black hole mass (MBH) measurements from reverberation mapping, as well as the first calibration of the V-band Tully-Fisher relation. Combining our measurements of H I 21 cm emission with Hubble Space Telescope and ground-based optical and near-infr…
Possible evidence of a universal radio/X-ray correlation in a near-complete sample of hard X-ray selected seyfert galaxies
Ho, L. C.; Chang, N.; Xie, F. G. +4 more
Because the disc-jet coupling likely depends on various properties of sources probed, the sample control is always an important but challenging task. In this work, we re-analysed the INTEGRAL hard X-ray-selected sample of Seyfert galaxies. We only consider sources that have measurements in black hole (BH) mass, and luminosities in radio and X-rays…