Determining the Co-Rotation Radii of Spiral Galaxies Using Spiral Arm Pitch Angle Measurements at Multiple Wavelengths

Abstract

The spiral arms spanning disk galaxies are believed to be created by density waves that propagate through galactic disks. We present a novel method of finding the co-rotation radius where the spiral arm pattern speed matches the velocities of the stars within the disk. Our method uses an image-overlay technique, which involves tracing the arms of spiral galaxies on images observed in different wavelengths. Density wave theory predicts that spiral arms observed from different wavelengths show a phase crossing at the co-rotation radius. For the purpose of this study, 20 nearby galaxies were analyzed in four different wavelengths with pitch angle measurements performed by two independent methods. We used optical wavelength images ($B$-band 440nm), two infrared wavelength images provided by Spitzer (3.6$\mu$m and 8$\mu$m) and ultraviolet images from GALEX (1350Å, 1750Å). The results were compared and verified with other records found in the literature. We then found rotation curve data for six of our galaxies and used our co-rotation radii estimates to measure the time that would elapse between star formation and moving to their observed positions in the $B$-band spirals. The average time lapse for this motion was found to be $\sim$ 50 Myr. The success of this new method of finding the co-rotation radius confirms density wave theory in a very direct way.

arXiv comment9 pages, 10 figures, 4 tables

References in corpus (25)

• THINGS: The HI Nearby Galaxy Survey
• Transient spirals as superposed instabilities
• H-alpha Kinematics of the SINGS Nearby Galaxies Survey. I
• Dynamics of stars around spiral arms in an N-body/SPH simulated barred-spiral galaxy
• Determining Star Formation Timescale and Pattern Speed in Nearby Spiral Galaxies
• Geometrically Derived Timescales for Star Formation in Spiral Galaxies
• Measurement of Galactic Logarithmic Spiral Arm Pitch Angle Using Two-Dimensional Fast Fourier Transform Decomposition
• Discovery of a relationship between spiral arm morphology and supermassive black hole mass in disk galaxies
• Observational Evidence Against Long-Lived Spiral Arms in Galaxies
• Spiral Instabilities in N-body Simulations I: Emergence from Noise
• Constraining corotation from shocks in tightly-wound spiral galaxies
• Spiral density wave triggering of star formation in SA and SAB galaxies
• Radial Metallicity Distribution Breaks at Corotation Radius in Spiral Galaxies
• A Morphological Method to Determine Co-Rotation Radii in Spiral Galaxies
• The Lifetime of Grand Design
• Beyond Ellipse(s): Accurately Modelling the Isophotal Structure of Galaxies with $Isofit$ and $Cmodel$
• Pattern Corotation Radii from Potential-Density Phase-Shifts for 153 OSUBGS Sample Galaxies
• Dependence of Spiral Arms Pitch Angle on Wavelength as a Test of Density Wave Theory
• Strong Evidence for the Density-wave Theory of Spiral Structure in Disk Galaxies
• The Halos and Environments of Nearby Galaxies (HERON) I: Imaging, Sample Characteristics, and Envelope Diameters
• A multi-wavelength study of spiral structure in galaxies. I. General characteristics in the optical
• A direct test of density wave theory in a grand-design spiral galaxy
• On the 3D dynamics and morphology of inner rings
• Investigating the Origins of Spiral Structure in Disk Galaxies through a Multiwavelength Study
• Spirality: A Novel Way to Measure Spiral Arm Pitch Angle

Cited by in corpus (9)

• Wide-field CO isotopologue emission and the CO-to-H${}_2$ factor across the nearby spiral galaxy M101
• Evidence in favour of density wave theory through star formation history maps and spatially resolved stellar clusters
• Galaxies decomposition with spiral arms -- II: A multiwavelength case study of M 51
• Refining the mass estimate for the intermediate-mass black hole candidate in NGC 3319
• Probing the Low-mass End of the Black Hole Mass Function via a Study of Faint Local Spiral Galaxies
• Resonance coupling in spiral arms: Patterns for flat rotation curve
• Identification of Intermediate-mass Black Hole Candidates Among a Sample of Sd Galaxies
• A Comprehensive Analysis on the Nature of the Spiral Arms in NGC 3686, NGC 4321, and NGC 2403
• Morphology and kinematics of the gas in M51: How interaction with NGC5195 has moulded the structure of its arms