Search Publications
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…
Multiple Stellar Populations at Less-evolved Stages: Detection of Chemical Variations among Main-sequence Dwarfs in NGC 1978
Milone, Antonino P.; Hong, Jongsuk; de Grijs, Richard +4 more
Multiple stellar populations (MPs) with different chemical compositions are not exclusive features of old globular clusters (older than 10 Gyr). Indeed, recent studies reveal that younger clusters (∼2-6 Gyr-old) in the Magellanic Clouds also exhibit star-to-star chemical variations among evolved stars. However, whether MPs are present among less-e…
Particle Reacceleration by Turbulence and Radio Constraints on Multimessenger High-energy Emission from the Coma Cluster
Murase, Kohta; Nishiwaki, Kosuke; Asano, Katsuaki
Galaxy clusters are considered to be gigantic reservoirs of cosmic rays (CRs). Some of the clusters are found with extended radio emission, which provides evidence for the existence of magnetic fields and CR electrons in the intra-cluster medium. The mechanism of radio halo (RH) emission is still under debate, and it has been believed that turbule…
Solar Orbiter/RPW antenna calibration in the radio domain and its application to type III burst observations
Maksimovic, M.; Bale, S. D.; Chust, T. +18 more
Context. In order to allow for a comparison with the measurements from other antenna systems, the voltage power spectral density measured by the Radio and Plasma waves receiver (RPW) on board Solar Orbiter needs to be converted into physical quantities that depend on the intrinsic properties of the radiation itself (e.g., the brightness of the sou…
Surface roughness of asteroid (162173) Ryugu and comet 67P/Churyumov-Gerasimenko inferred from in situ observations
Jaumann, R.; Stephan, K.; Mottola, S. +28 more
Alteration processes on asteroid and comet surfaces, such as thermal fracturing, (micrometeorite) impacts or volatile outgassing, are complex mechanisms that form diverse surface morphologies and roughness on various scales. These mechanisms and their interaction may differ on the surfaces of different bodies. Asteroid Ryugu and comet 67P/Churyumo…