Related papers: A Parallax-based Distance Estimator for Spiral Arm…

From the sun's location in the Galactic disk, one can use different arm tracers (CO, HII, thermal or ionized or relativistic electrons, masers, cold or hot dust, etc) to locate a tangent to each spiral arm in the disk of the Milky Way…

We report the results of the measurement of the trigonometric parallax of an H$_2$O maser source in \r22 with the VLBI Exploration of Radio Astrometry (VERA). The annual parallax was determined to be 0.314$\pm$0.070~mas, corresponding to a…

We are conducting a large program with the NRAO Very Long Baseline Array (VLBA) to measure trigonometric parallaxes of massive star-forming regions across the Milky Way. Here we report measurement of the parallax and proper motion of…

We present a new face-on map of dense neutral atomic hydrogen (HI) gas in the outer Galaxy. Our map has been produced from the Leiden/Argentine/Bonn (LAB) HI 21-cm line all-sky survey by finding intensity maxima along every line of sight…

The density wave theory predicted some physical offsets among different tracers of star formation. To test this prediction, here we compiled data on 40 galaxies searched observationally for a physical offset between spiral arm tracers, and…

We investigate the use of HI data to resolve the near/far ambiguity in kinematic distances of massive young stellar object (MYSO) candidates. Kinematic distances were obtained from 13CO 1-0 spectral line observations with the Mopra…

We present new gas flow models for the Milky Way inside the solar circle. Using a mass model derived from the COBE/DIRBE maps and clump giant star counts, and using a parametric model for the spiral arm pattern in the disk, we calculate the…

We infer distances and their asymmetric uncertainties for two million stars using the parallaxes published in the Gaia DR1 (GDR1) catalogue. We do this with two distance priors: A minimalist, isotropic prior assuming an exponentially…

It is imperative to map the strength and distribution of feedback in galaxies to understand how feedback affects the galactic ecosystems. H$_2$O masers act as indicators of energy injection into the ISM. Our goal is to measure the strength…

Converting a noisy parallax measurement into a posterior belief over distance requires inference with a prior. Usually this prior represents beliefs about the stellar density distribution of the Milky Way. However, multi-band photometry…

Maps of Energetic Neutral Atom (ENA) fluxes obtained from Interstellar Boundary Explorer (IBEX) observations revealed a bright structure extending over the sky, subsequently dubbed the IBEX ribbon. The ribbon had not been expected from the…

Context. Spiral arms in protoplanetary disks could be shown to be the manifestation of density waves launched by protoplanets and propagating in the gaseous component of the disk. At least two point sources have been identified in the L…

The spiral structure of our Milky Way has not yet been well outlined. HII regions, giant molecular clouds (GMCs) and 6.7-GHz methanol masers are primary tracers for spiral arms. We collect and update the database of these tracers which has…

We report on trigonometric parallax measurements for the Galactic star forming region G14.33-0.64 toward the Sagittarius spiral arm. We conducted multi-epoch phase-referencing observations of an H2O maser source in G14.33-0.64 with the…

The Milky Way spiral arms are well established from star counts as well as from the locus of molecular clouds and other young objects, however, they have only recently started to be observed from a kinematics point of view. Using the…

Using simulations of box/peanut- (B/P-) shaped bulges, we explore the nature of the X-shape of the Milky Way's bulge. An X-shape can be associated with a B/P-shaped bulge driven by a bar. By comparing in detail the simulations and the…

Spiral density wave theory attempts to describe the spiral pattern in spiral galaxies in terms of a long-lived wave structure with a constant pattern speed in order to avoid the winding dilemma. The pattern is consequently a rigidly…

We present the results of determining the parameters of the spiral arms of the Galaxy using the stars Gaia DR3, whose absolute magnitude is $M_G$ < 4, and which allow tracing spiral arms at large distances from the Sun. As tracers of spiral…

Studying the nature of spiral arms is essential for understanding the formation of the intricate disc structure of the Milky Way. The European Space Agency's Gaia mission has provided revolutionary observational data that have uncovered…

Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object…