Discovery of a filamentary synchrotron structure connected to the coherent magnetic field in the outer Galaxy

Abstract

Using data from the Galactic Arecibo L-band Feed Array Continuum Transit Survey (GALFACTS), we report the discovery of two previously unidentified, very compressed, thin, and straight polarized filaments approximately centred at Galactic coordinates, $(l,b)=(182.5^{\circ },-4.0^{\circ })$, which we call G182.5--4.0. Using data from the Isaac Newton Telescope Galactic Plane Survey (IGAPS), we also find straight, long, and extremely thin H$\alpha$ filaments coincident with the radio emission. These filaments are positioned in projection at the edge of the Orion-Eridanus superbubble and we find evidence indicating that the filaments align with the coherent magnetic field of the outer Galaxy. We find a lower limit on the total radio flux at 1.4~GHz to be $0.7\pm 0.3$~Jy with an average linearly polarized fraction of $40\begin{array}{c}+30\\ -20\end{array}\%$. We consider various scenarios that could explain the origin of these filaments, including a shell-type supernova remnant (SNR), a bow shock nebula associated with a pulsar, or relic fragments from one or more supernova explosions in the adjacent superbubble, with a hybrid scenario being most likely. This may represent an example of a new class of objects that is neither an SNR nor a bow shock. The highly compressed nature of these filaments and their alignment with Galactic plane suggests a scenario where this object formed in a magnetic field that was compressed by the expanding Orion-Eridanus superbubble, suggesting that the object is related to this superbubble and implying a distance of $\sim$400~pc.

arXiv comment17 pages, 9 figures, accepted to Astrophysical Journal

References in corpus (46)

• Gaia Data Release 2. Summary of the contents and survey properties
• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• The GMRT 150 MHz All-sky Radio Survey: First Alternative Data Release TGSS ADR1
• The Evolution and Structure of Pulsar Wind Nebulae
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Faraday Rotation Measure Synthesis
• A New Model of the Galactic Magnetic Field
• The LOFAR Two-metre Sky Survey - II. First data release
• The LOFAR Two-metre Sky Survey -- V. Second data release
• 9286 Stars: An Agglomeration of Stellar Polarization Catalogs
• Magnetic Fields in Spiral Galaxies
• The VLA Low-frequency Sky Survey
• EMU: Evolutionary Map of the Universe
• The Wisconsin H-Alpha Mapper Northern Sky Survey
• Radio observational constraints on Galactic 3D-emission models
• GLEAM: The GaLactic and Extragalactic All-sky MWA survey
• A revised catalogue of 294 Galactic supernova remnants
• Magnetically Aligned HI Fibers and the Rolling Hough Transform
• Meeting the Cool Neighbors VIII: A preliminary 20-parsec census from the NLTT catalogue
• The Second Data Release of the INT Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2)
• The Mouse That Soared: High Resolution X-ray Imaging of the Pulsar-Powered Bow Shock G359.23-0.82
• Magnetic fields in supernova remnants and pulsar-wind nebulae
• The 1.28 GHz MeerKAT Galactic Center Mosaic
• Modelling the Galactic Magnetic Field on the Plane in 2D
• The Synthesis Telescope at the Dominion Radio Astrophysical Observatory
• The nature of bilateral supernova remnants
• High angular resolution Sunyaev-Zel'dovich observations of MACS J1423.8+2404 with NIKA: Multiwavelength analysis
• Linear polarization structures in LOFAR observations of the interstellar medium in the 3C196 field
• A Sino-German 6 cm polarization survey of the Galactic plane II. The region from 129 degree to 230 degree longitude
• Nested shells reveal the rejuvenation of the Orion-Eridanus superbubble
• The Connection between Supernova Remnants and the Galactic Magnetic Field: A Global Radio Study of the Axisymmetric Sample
• Galactic interstellar filaments as probed by LOFAR and Planck
• Gas shells and magnetic fields in the Orion-Eridanus superbubble
• Orion A's complete 3D magnetic field morphology
• Far UV and Optical Emissions from Three Very Large Supernova Remnants Located at Unusually High Galactic Latitudes
• New high-resolution radio observations of the SNR CTB 80
• Modelling interstellar structures around Vela X-1
• A Unified Model for the Fan Region and the North Polar Spur: A bundle of filaments in the Local Galaxy
• An In Situ Study of Turbulence Near Stellar Bow Shocks
• ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament
• Discovery of a Thirty-Degree Long Ultraviolet Arc in Ursa Major
• The Long Filament of PSR J2030+4415
• MeerKAT discovery of radio emission from the Vela X-1 bow shock
• Galactic Centre Threads as Nuclear MHD Waves
• Thermal emission from bow shocks II: 3D magnetohydrodynamic models of Zeta Ophiuchi
• A Comparison of Multi-Phase Magnetic Field Tracers in a High-Galactic Latitude Region of the Filamentary Interstellar Medium

Cited by in corpus (2)

• Neutral hydrogen filaments in interstellar media: Are they physical?
• Andromeda's tenuous veil: A likely Milky Way nebula projected toward M31