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Weighing the Galactic disk using phase-space spirals. I. Tests on one-dimensional simulations
de Salas, P. F.; Widmark, A.; Laporte, C.
We present a new method for inferring the gravitational potential of the Galactic disk, using the time-varying structure of a phase-space spiral in the (z, w)-plane (where z and w represent vertical position and vertical velocity). Our method of inference extracts information from the shape of the spiral and disregards the bulk density distributio…
Gaia Early Data Release 3
Kotak, Rubina; Forveille, Thierry
What Makes Quadruply Lensed Quasars Quadruple?
Schechter, Paul L.; Luhtaru, Richard; de Soto, Kaylee M.
Among known strongly lensed quasar systems, ~25% have gravitational potentials sufficiently flat (and sources sufficiently well aligned) to produce four images rather than two. The projected flattening of the lensing galaxy and tides from neighboring galaxies both contribute to the potential's quadrupole. Witt's hyperbola and Wynne's ellipse permi…
Search for globular clusters associated with the Milky Way dwarf galaxies using Gaia DR2
Koposov, Sergey E.; Huang, Kuan-Wei
We report the result of searching for globular clusters (GCs) around 55 Milky Way (MW) satellite dwarf galaxies within the distance of 450 kpc from the Galactic Centre except for the Large and Small Magellanic Clouds and the Sagittarius dwarf. For each dwarf, we analyse the stellar distribution of sources in Gaia DR2, selected by magnitude, proper…
Pulsational instability of pre-main-sequence models from accreting protostars. I. Constraining the input physics for accretion with spectroscopic parameters and stellar pulsations
Zwintz, K.; Barnes, T. G.; Steindl, T. +2 more
Context. The picture of pre-main-sequence evolution is often simplified by the application of classical initial models. Such models have large initial radii and sufficient uniform contraction to make them fully convective, however, real stars are born as small protostellar seeds in collapsing molecular clouds and obtain their final mass by means o…
Flux conservation, radial scalings, Mach numbers, and critical distances in the solar wind: magnetohydrodynamics and Ulysses observations
Verscharen, Daniel; Velli, Marco; Bale, Stuart D.
One of the key challenges in solar and heliospheric physics is to understand the acceleration of the solar wind. As a super-sonic, super-Alfvénic plasma flow, the solar wind carries mass, momentum, energy, and angular momentum from the Sun into interplanetary space. We present a framework based on two-fluid magnetohydrodynamics to estimate the flu…
Strong dependence of the physical properties of cores on spatial resolution in observations and simulations
Men'shchikov, A.; Didelon, P.; Motte, F. +3 more
The angular resolution of a telescope is the primary observational parameter, along with the detector sensitivity in defining the quality of the observed images and of the subsequent scientific exploitation of the data. During the last decade in star formation research, many studies have targeted low- and high-mass star formation regions located a…
A Case against a Significant Detection of Precession in the Galactic Warp
López-Corredoira, M.; Chrobáková, Ž.
Recent studies of warp kinematics using Gaia DR2 data have produced detections of warp precession for the first time, which greatly exceeds theoretical predictions of models. However, this detection assumes a warp model derived for a young population (few tens of megayears) to fit velocities of an average older stellar population of the thin disk …
Strong Mg II and Fe II Absorbers at 2.2 < z < 6.0
Willott, Chris J.; Shen, Yue; Ho, Luis C. +13 more
We present a study of strong intervening absorption systems in the near-IR spectra of 31 luminous quasars at z > 5.7. The quasar spectra were obtained with Gemini GNIRS that provide continuous wavelength coverage from ∼0.9 to ∼2.5 µm. We detect 32 strong Mg II doublet absorbers with rest-frame equivalent width Wr(λ2796) > 1.…
Dynamical Masses and Stellar Evolutionary Model Predictions of M Stars
Herczeg, Gregory J.; Wilner, David J.; Andrews, Sean M. +9 more
In this era of Gaia and ALMA, dynamical stellar mass measurements, derived from spatially and spectrally resolved observations of the Keplerian rotation of circumstellar disks, provide benchmarks that are independent of observations of stellar characteristics and their uncertainties. These benchmarks can then be used to validate and improve stella…