| 1. |
- Falconer, D., et al.
(författare)
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New Air-interface Technologies and Deployment Concepts
- 2006
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Ingår i: Technologies for the Wireless Future: Wireless World Research Forum (WWRF). - Chichester, UK : John Wiley & Sons. - 0470029056 - 9780470029053 ; , s. 131-226
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Yang, Xiaolong, et al.
(författare)
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Extended Catalog of Winged or X-shaped Radio Sources from the FIRST Survey
- 2019
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Ingår i: Astrophysical Journal, Supplement Series. - : American Astronomical Society. - 1538-4365 .- 0067-0049. ; 245:1
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Tidskriftsartikel (refereegranskat)abstract
- We present a catalog of 290 ?winged? or X-shaped radio galaxies (XRGs) extracted from the latest (2014 December 17) data release of the ?Very Large Array Faint Images of the Radio Sky at Twenty centimeter.? We have combined these radio images with their counterparts in the TIFR GMRT sky survey at 150 MHz, in an attempt to identify any low surface brightness radio emission present in these sources. This has enabled us to assemble a sample of 106 ?strong? XRG candidates and 184 ?probable? XRG candidates whose XRG designation needs to be verified by further observations. The present sample of 290 XRG candidates is almost twice as large as the number of XRGs currently known. Twenty-five of our 290 XRG candidates (9 ?strong? and 16 ?probable?) are identified as quasars. Double-peaked narrow emission lines are seen in the optical spectra of three of the XRG candidates (two ?strong? and one ?probable?). Nearly 90% of the sample is located in the FR II domain of the Owen?Ledlow diagram. A few of the strong XRG candidates have a rather flat radio spectrum (spectral index ? flatter than ?0.3) between 150 MHz and 1.4 GHz, or between 1.4 and 5 GHz. Since this is not expected for lobe-dominated extragalactic radio sources (like nearly all known XRGs), these sources are particularly suited for follow-up radio imaging and near-simultaneous measurement of the radio spectrum.
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| 3. |
- Yang, Xiaolong, et al.
(författare)
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The X-shaped Radio Galaxy J0725+5835 is Associated with an AGN Pair
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 933:1
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Tidskriftsartikel (refereegranskat)abstract
- X-shaped radio galaxies (XRGs) are those that exhibit two pairs of unaligned radio lobes (main radio lobes and wings). One of the promising models for the peculiar morphology is jet reorientation. To clarify this, we conducted a 5 GHz observation with the European VLBI Network (EVN) of XRG J0725+5835, which resembles the archetypal binary active galactic nuclei (AGNs) 0402+379 in radio morphology, but it is larger in angular size. In our observation, two milliarcsecond-scale radio components with nonthermal radio emission are detected. Each of them coincides with an optical counterpart with similar photometric redshift and (optical and infrared) magnitude, corresponding to dual active nuclei. Furthermore, with the improved Very Large Array (VLA) images, we find a bridge between the two radio cores and a jet bending in the region surrounding the companion galaxy. This further supports the interplay between the main and companion galaxies. In addition, we also report the discovery of an arcsecond-scale jet in the companion. Given the projected separation of similar to 100 kpc between the main and companion galaxies, XRG J0725+5835 is likely associated with a dual jetted-AGN system. In both EVN and VLA observations, we find signatures that the jet is changing its direction, which is likely responsible for the X-shaped morphology. For the origin of jet reorientation, several scenarios are discussed.
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