Power Spectrum Analysis of Polarized Emission from the Canadian Galactic Plane Survey

Abstract

Angular power spectra are calculated and presented for the entirety of the Canadian Galactic Plane Survey polarization dataset at 1.4 GHz covering an area of 1060 deg${}^2$. The data analyzed are a combination of data from the 100-m Effelsberg Telescope, the 26-m Telescope at the Dominion Radio Astrophysical Observatory, and the Synthesis Telescope at the Dominion Radio Astrophysical Observatory, allowing all scales to be sampled down to arcminute resolution. The resulting power spectra cover multipoles from $\ell \approx 60$ to $\ell \approx 10^4$ and display both a power-law component at low multipoles and a flattening at high multipoles from point sources. We fit the power spectrum with a model that accounts for these components and instrumental effects. The resulting power-law indices are found to have a mode of 2.3, similar to previous results. However, there are significant regional variations in the index, defying attempts to characterize the emission with a single value. The power-law index is found to increase away from the Galactic plane. A transition from small-scale to large-scale structure is evident at $b=9^{\circ }$, associated with the disk-halo transition in a 15${}^{\circ }$ region around $l=108^{\circ }$. Localized variations in the index are found toward HII regions and supernova remnants, but the interpretation of these variations is inconclusive. The power in the polarized emission is anticorrelated with bright thermal emission (traced by H$\alpha$ emission) indicating that the thermal emission depolarizes background synchrotron emission.

arXiv commentAccepted to ApJ; 17 pages

References in corpus (26)

• A Full-Sky H-alpha Template for Microwave Foreground Prediction
• The Distance to the Perseus Spiral Arm in the Milky Way
• Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region
• The outer scale of turbulence in the magneto-ionized Galactic interstellar medium
• Water maser motions in W3(OH) and a determination of its distance
• An absolutely calibrated survey of polarized emission from the northern sky at 1.4 GHz
• Low-Mach-number turbulence in interstellar gas revealed by radio polarization gradients
• Towards a model of full-sky Galactic synchrotron intensity and linear polarisation: a re-analysis of the Parkes data
• Statistical Description of Synchrotron Intensity Fluctuations: Studies of Astrophysical Magnetic Turbulence
• Enhanced small-scale Faraday rotation in the Galactic spiral arms
• Radio Polarization from the Galactic Plane in Cygnus
• A Sino-German 6 cm polarization survey of the Galactic plane II. The region from 129 degree to 230 degree longitude
• A Survey of the Polarized Emission from the Galactic Plane at 1420 MHz with Arcminute Angular Resolution
• Magnetic Fields and Ionized Gas in the inner Galaxy: An Outer Scale for Turbulence and the Possible Role of HII Regions
• Characteristics of the structure in the Galactic polarized radio background at 350 MHz
• Faraday screens associated with local molecular clouds
• High Galactic latitude polarized emission at 1.4 GHz and implications for cosmic microwave background observations
• The DRAO Planck Deep Fields: the polarization properties of radio galaxies at 1.4 GHz
• The Supernova Remnant CTB104A : Magnetic Field Structure and Interaction with the Environment
• The JCMT 12CO(3-2) Survey of the Cygnus X Region: I. A Pathfinder
• The angular power spectra of polarized Galactic synchrotron
• The angular power spectrum of radio emission at 2.3 GHz
• The power-law behaviours of angular spectra of polarized Galactic synchrotron
• Polarization angular spectra of Galactic synchrotron emission on arcminute scales
• The Parkes Galactic Meridian Survey (PGMS): observations and CMB polarization foreground analysis
• A multifrequency angular power spectrum analysis of the Leiden polarization surveys

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• Revisiting Rotation Measures from the Canadian Galactic Plane Survey: the Magnetic Field in the Disk of the Outer Galaxy
• Multiscale Analysis of the Gradient of Linear Polarisation
• Polarization Gradient Study of Interstellar Medium Turbulence Using The Canadian Galactic Plane Survey
• A pioneering experiment combining single-antenna and aperture-synthesis data to measure Faraday rotation with GMIMS and the CGPS