Constraining the pitch angle of the Galactic spiral arms in the Milky Way

Abstract

We carry out analyses of some parameters of the galactic spiral arms, in the currently available samples. We present a catalog of the observed pitch angle for each spiral arm in the Milky Way disk. For each long spiral arm in the Milky Way, we investigate for each individual arm its pitch angle, as measured through different methods (parallaxes, twin-tangent arm, kinematical, etc), and assess their answers. Second, we catalog recent advances in the cartography of the Galaxy (global mean arm pitch, arm number, arm shape, interarm distance at the Sun). We statistically compare the results over a long time frame, from 1980 to 2017. Histograms of about 90 individual results published in recent years (since mid-2015) are compared to 66 earlier results (from 1980 to 2005), showing the ratio of primary to secondary peaks to have increased by almost a factor of 3. Similarly, many earlier discrepancies (expressed in r.m.s.) have been reduced by almost a factor 3.

24 pages, 5 figures (15 panels), 3 tables, 1 appendix

References in corpus (27)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• Physical properties of molecular clouds for the entire Milky Way disk
• The observed spiral structure of the Milky Way
• Trigonometric Parallaxes of Star Forming Regions in the Perseus Spiral Arm
• The local spiral structure of the Milky Way
• Trigonometric Parallaxes of Star Forming Regions in the Scutum Spiral Arm
• A Possible Extension of the Scutum-Centaurus Arm into the Outer Second Quadrant
• The evolution of the Milky Way: New insights from open clusters
• Catalog of observed tangents to the spiral arms in the Milky Way galaxy
• Parallaxes of Star Forming Regions in the Outer Spiral Arm of the Milky Way
• Clustering of Local Group distances: publication bias or correlated measurements? II. M31 and beyond
• Clustering of Local Group distances: publication bias or correlated measurements? IV. The Galactic Center
• Recent advances in the determination of some Galactic constants in the Milky Way
• Tracing the Spiral Structure of the Outer Milky Way with Dense Atomic Hydrogen Gas
• The prevalence of star formation as a function of Galactocentric radius
• First Parallax Measurements Towards a 6.7 GHz Methanol Maser with the Australian Long Baseline Array - Distance to G339.884-1.259
• Data Compression for the Tomo-e Gozen with Low-rank Matrix Approximation
• Analysis of Determinations of the Distance between the Sun and the Galactic Center
• The Gentle Growth of Galaxies at High Redshifts in Overdense Environments
• Parallaxes of 6.7-GHz Methanol Masers towards the G305.2 High-Mass Star Formation Region
• Dynamical Configurations of Celestial Systems Comprised of Multiple Irregular Bodies
• An analysis of star formation with Herschel in the Hi-GAL Survey. II. The tips of the Galactic bar
• The Norma spiral arm: large-scale pitch angle
• Outer Rotation Curve of the Galaxy with VERA II: Annual Parallax and Proper Motion of the Star-Forming Region IRAS21379+5106
• Structure and Dynamics of the Milky Way: The Evolving Picture
• Galactic Kinematics from Data on Open Star Clusters from the MWSC Catalogue
• Molecular Gas in the Outskirts of Galaxies

Cited by in corpus (17)

• A guided map to the Spiral arms in the galactic disk of the Milky Way
• The Imprint of Spiral Arms on the Galactic Rotation Curve
• Analysis of galaxy kinematics based on Cepheids from the Gaia DR2 Catalogue
• Using classical Cepheids to study the far side of the Milky Way disk. II. The spiral structure in the first and fourth Galactic quadrants
• Modeling of Spiral Structure in a Multi-Component Milky~Way-Like Galaxy
• Catalog of spiral arm Tangents (Galactic Longitudes) in the Milky Way, and the Age Gradient based on various arm tangents
• A New Multi-Tracer Approach to Defining the Spiral arm width in the Milky Way
• Kinematics of the Galaxy from a Sample of Young Open Star Clusters with Data from the Gaia DR2 Catalogue
• The Observed Age Gradient in the Milky Way -- as a Test for theories of spiral arm structure
• First spiral arm detection using dynamical mass measurements of the Milky Way disk
• Study of the Galactic Rotation Based on Masers and Radio Stars with VLBI Measurements of Their Parallaxes
• Galactic Rotation Based on OB Stars from the Gaia DR2 Catalogue
• Determination of the Spiral Pattern Speed in the Galaxy from Three Samples of Stars
• Interarm islands in the Milky Way -- the one near the Cygnus spiral arm
• The Mysterious Radcliffe Wave
• Redetermination of the Parameters of the Galactic Spiral Pattern from Classical Cepheids
• Estimation of the Parameters of the Spiral Pattern in the Galaxy Based on a Sample of Classical Cepheids