Interacting Large-Scale Magnetic Fields and Ionised Gas in the W50/SS433 System

Abstract

The W50/SS433 system is an unusual Galactic outflow-driven object of debatable origin. We have used the Australia Telescope Compact Array (ATCA) to observe a new 198 pointing mosaic, covering $3^{\circ }\times 2^{\circ }$, and present the highest-sensitivity full-Stokes data of W50 to date using wide-field, wide-band imaging over a 2 GHz bandwidth centred at 2.1 GHz. We also present a complementary H$\alpha$ mosaic created using the Isaac Newton Telescope Photometric H$\alpha$ Survey of the Northern Galactic Plane (IPHAS). The magnetic structure of W50 is found to be consistent with the prevailing hypothesis that the nebula is a reanimated shell-like supernova remnant (SNR), that has been re-energised by the jets from SS433. We observe strong depolarization effects that correlate with diffuse H$\alpha$ emission, likely due to spatially-varying Faraday rotation measure (RM) fluctuations of $\ge 48$ to 61 rad m${}^{-2}$ on scales $\le 4.5$ to 6 pc. We also report the discovery of numerous, faint, H$\alpha$ filaments that are unambiguously associated with the central region of W50. These thin filaments are suggestive of a SNR's shock emission, and almost all have a radio counterpart. Furthermore, an RM-gradient is detected across the central region of W50, which we interpret as a loop magnetic field with a symmetry axis offset by $\approx 90^{\circ }$ to the east-west jet-alignment axis, and implying that the evolutionary processes of both the jets and the SNR must be coupled. A separate RM-gradient is associated with the termination shock in the Eastern ear, which we interpret as a ring-like field located where the shock of the jet interacts with the circumstellar medium. Future optical observations will be able to use the new H$\alpha$ filaments to probe the kinematics of the shell of W50, potentially allowing for a definitive experiment on W50's formation history.

arXiv commentSubmitted to MNRAS

References in corpus (50)

• The ATNF Pulsar Catalogue
• The ATNF Pulsar Catalogue
• Faraday Rotation Measure Synthesis
• Pulsar rotation measures and the large-scale structure of Galactic magnetic field
• The Australia Telescope Compact Array Broadband Backend (CABB)
• The outer scale of turbulence in the magneto-ionized Galactic interstellar medium
• Pulsar rotation measures and the magnetic structure of our Galaxy
• Rotation Measures of Extragalactic Sources Behind the Southern Galactic Plane: New Insights into the Large-Scale Magnetic Field of the Inner Milky Way
• Modeling the Magnetic Field in the Galactic Disk using New Rotation Measure Observations from the Very Large Array
• Estimating extragalactic Faraday rotation
• Complex Faraday depth structure of Active Galactic Nuclei as revealed by broadband radio polarimetry
• The Second Data Release of the INT Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2)
• Powerful radiative jets in super-critical accretion disks around non-spinning black holes
• Symmetry in the changing jets of SS433 and its true distance from us
• Magnetic Fields in Large Diameter HII Regions Revealed by the Faraday Rotation of Compact Extragalactic Radio Sources
• Enhanced small-scale Faraday rotation in the Galactic spiral arms
• Arecibo 430 MHz Pulsar Polarimetry: Faraday Rotation Measures and Morphological Classifications
• The effect of HII regions on rotation measure of pulsars
• The Distance to SS433/W50 and its Interaction with the ISM
• Comparison of algorithms for determination of rotation measure and Faraday structure I. 1100 - 1400 MHz
• When Microquasar Jets and Supernova Collide: Hydrodynamically Simulating the SS433-W50 Interaction
• New Galactic supernova remnants discovered with IPHAS
• A Broadband Polarization Catalog of Extragalactic Radio Sources
• Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources
• Thermal plasma in the giant lobes of the radio galaxy Centaurus A
• A radio-polarisation and rotation measure study of the Gum Nebula and its environment
• Proper Motions of H-alpha filaments in the Supernova Remnant RCW 86
• Transverse Faraday-Rotation Gradients Across the Jets of 15 Active Galactic Nuclei
• Shape and evolution of wind-blown bubbles of massive stars: on the effect of the interstellar magnetic field
• Asymmetric supernova remnants generated by Galactic, massive runaway stars
• XMM-Newton observations of the eastern jet of SS433
• A study of broadband Faraday rotation and polarization behaviour over 1.3--10 GHz in 36 discrete radio sources
• Faraday rotation of the supernova remnant G296.5+10.0: Evidence for a Magnetized Progenitor Wind
• G309.2-00.6 and jets in supernova remnants
• Magnetized Gas in the Smith High Velocity Cloud
• Deep optical observations of the interaction of the SS 433 microquasar jet with the W 50 radio continuum shell
• A Sino-German $\lambda$6\ cm polarization survey of the Galactic plane. V. Large supernova remnants
• Faraday Rotation in Pulsar Magnetosphere
• Absolutely calibrated radio polarimetry of the inner Galaxy at 2.3 GHz and 4.8 GHz
• Exploring the Intergalactic Magnetic Field by Means of Faraday Tomography
• Probing the history of SS433's jet kinematics via Decade-resolution radio observations of W50
• A Multi-Wavelength Study of the Western Lobe of W50 Powered by the Galactic Microquasar SS 433
• The Origin of Ionized Filaments Within the Orion-Eridanus Superbubble
• Magnetic fields of the W4 superbubble
• The Eastern Filament of W50
• The Emission Nebula Sh 2-174: A Radio Investigation of the Surrounding Region
• Jet propulsion of wind ejecta from a major flare in the black hole microquasar SS433
• Magnetic fields in the Southern Galactic Plane Survey
• Faraday Rotation Distributions from Stellar Magnetism in Wind-Blown Bubbles
• Revision of distance to SS433

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• Multiband counterparts of two eclipsing ultraluminous X-ray sources in M 51
• Constraints on particle acceleration in SS433/W50 from MAGIC and H.E.S.S. observations
• The Large-scale ISM of SS433/W50 Revisited
• LOFAR 150-MHz observations of SS 433 and W 50
• Continuous Jets and Backflow Models for the Formation of W50/SS433 in Magnetohydrodynamics Simulations
• A newly discovered double-double candidate microquasar in NGC 300
• Blazar jet evolution revealed by multi-epoch broadband radio polarimetry
• Magnetic Field Analysis of the Bow and Terminal Shock of the SS433 Jet
• Tentative evidence of spatially extended GeV emission from SS433/W50
• W 50 and SS 433
• A New Microquasar Candidate in M83
• Energy estimation of high energy particles associated with the SS433/W50 system through radio observation at 1.4 GHz
• Molecular clouds at the eastern edge of radio nebula W50
• X-ray panorama of the SS433/W50 complex by SRG/eROSITA
• Optical IFU spectroscopy of a bipolar microquasar jet in NGC 300
• On the Formation of SS433
• Arcsecond-Scale X-ray Imaging and Spectroscopy of SS 433 with Chandra HETG
• PeV particle acceleration and non-thermal emission in the `minimalist' model of the extended jets in W50/SS433
• Hard X-ray emission from the eastern jet of SS 433 powering the W50 `Manatee' nebula: Evidence for particle re-acceleration