CHANG-ES XI: Circular Polarization in the Cores of Nearby Galaxies

Abstract

We detect 5 galaxies in the CHANG-ES (Continuum Halos in Nearby Galaxies -- an EVLA Survey) sample that show circular polarization (CP) at L-band in our high resolution data sets. Two of the galaxies (NGC~4388 and NGC~4845) show strong Stokes $V/I\equiv m_C\sim 2$\%, two (NGC~660 and NGC~3628) have values of $m_C\sim 0.3$\%, and NGC~3079 is a marginal detection at $m_C\sim 0.2$\%. The two strongest $m_C$ galaxies also have the most luminous X-ray cores and the strongest internal absorption in X-rays. We have expanded on our previous Faraday conversion interpretation and analysis and provide analytical expressions for the expected $V$ signal for a general case in which the cosmic ray electron energy spectral index can take on any value. We provide examples as to how such expressions could be used to estimate magnetic field strengths and the lower energy cutoff for CR electrons. Four out of our detections are {\it resolved}, showing unique structures, including a {\it jet} in NGC~4388 and a CP `conversion disk' in NGC~4845. The conversion disk is inclined to the galactic disk but is perpendicular to a possible outflow direction. Such CP structures have never before been seen in any galaxy to our knowledge. None of the galaxy cores show linear polarization at L-band. Thus CP may provide a unique probe of physical conditions deep into radio AGNs.

arXiv comment30 pages, 4 figures, accepted to MNRAS

References in corpus (52)

• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• A multi-scale multi-frequency deconvolution algorithm for synthesis imaging in radio interferometry
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• An Accurate Flux Density Scale from 1 to 50 GHz
• The non-coplanar baselines effect in radio interferometry: The W-Projection algorithm
• Emission Beam Geometry of Selected Pulsars Derived from Average Pulse Polarization Data
• Alignment of Magnetized Accretion Disks and Relativistic Jets with Spinning Black Holes
• Towards a Complete Census of AGNs in Nearby Galaxies: A Large Population of Optically Unidentified AGNs
• Placing Confidence Limits on Polarization Measurements
• The subarcsecond mid-infrared view of local active galactic nuclei: I. The N- and Q-band imaging atlas
• The Geometry of and Mass Accretion Rate through the Maser Accretion Disk in NGC 4258
• Correcting direction-dependent gains in the deconvolution of radio interferometric images
• The XMM-Newton EPIC Background and the production of Background Blank Sky Event Files
• Evidence for a Geometrically Thick Self-Gravitating Accretion Disk in NGC 3079
• CHANG-ES IV: Radio continuum emission of 35 edge-on galaxies observed with the Karl G. Jansky Very Large Array in D-configuration, Data Release 1
• The faintest Seyfert radio cores revealed by VLBI
• Tightly Correlated X-ray/H$\alpha$ Emitting Filaments in the Superbubble and Large-Scale Superwind of NGC 3079
• Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- I: Introduction to the Survey
• The Spectrum and Variability of Circular Polarization in Sagittarius A* from 1.4 to 15 GHz
• X-ray nature of the LINER nuclear sources
• Circular Polarization of Radio Emission from Relativistic Jets
• Detection and Measurement of Parsec-Scale Circular Polarization in Four AGN
• Further Clues to the Nature of Composite LINER/HII Galaxies
• MOJAVE: Monitoring of Jets in AGN with VLBA Experiments - II. First-Epoch 15 GHz Circular Polarization Results
• Parsec-Scale Circular Polarization Observations of 40 Blazars
• The X-ray nebula around the Seyfert 2 galaxy NGC4388
• The Central Engines of 19 LINERs as Viewed by Chandra
• Low-luminosity Active Galaxies and their Central Black Holes
• Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- II: First Results on NGC 4631
• Dust in spiral galaxies: global properties
• Tidal disruption of a super-Jupiter by a massive black hole
• CHANG-ES V: Nuclear Radio Outflow in a Virgo Cluster Spiral after a Tidal Disruption Event
• CHANG-ES VI: Probing Supernova Energy Deposition in Spiral Galaxies Through Multi-Wavelength Relationships
• The Circular Polarization of Sagittarius A* at Submillimeter Wavelengths
• High Levels of Circularly Polarized Emission from the Radio Jet in NGC 1275 (3C 84)
• Jet-cloud collisions in the jet of the Seyfert galaxy NGC3079
• Full-Stokes polarimetry with circularly polarized feeds - Sources with stable linear and circular polarization in the GHz regime
• Detection of Circular Polarization in M81*
• CHANG-ES VII: Magnetic outflows from the Virgo cluster galaxy NGC 4388
• CHANG-ES III: UGC10288 -- An Edge-on Galaxy with a Background Double-lobed Radio Source
• Broadband radio circular polarization spectrum of the relativistic jet in PKS B2126-158
• Determining the radio AGN contribution to the radio-FIR correlation using the black hole fundamental plane relation
• First Detection of A Sub-kpc Scale Molecular Outflow in the Starburst Galaxy NGC 3628
• A new period of activity in the core of NGC660
• The "shook up" galaxy NGC 3079: the complex interplay between HI, activity and environment
• INTEGRAL 11-year hard X-ray survey above 100 keV
• Compact Resolved Ejecta in the Nearest Tidal Disruption Event
• Radio Linear and Circular Polarization from M81*
• Probing the Circular Polarization of Relativistic Jets on VLBI Scales
• A new method to suppress the bias in polarized intensity
• Linear and Circular Polarization from Sagittarius A* and M81*

Cited by in corpus (5)

• CHANG-ES XXII: Coherent Magnetic Fields in the Halos of Spiral Galaxies
• CHANG-ES XX. High Resolution Radio Continuum Images of Edge-on Galaxies and their AGNs -- Data Release 3
• CHANG-ES XIX: Galaxy NGC 4013 -- a diffusion-dominated radio halo with plane-parallel disk and vertical halo magnetic fields
• CHANG-ES XXXIV: Magnetic Field Structure in Edge-On Galaxies Characterising large-scale magnetic fields in galactic halos
• An underlying universal pattern in galaxy halo magnetic fields