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We present catalogues of discrete, compact radio sources in and around the discs of 35 edge-on galaxies in the Continuum Halos in Nearby Galaxies – an EVLA Survey. The sources were extracted using the pybdsf program at both 1.6 GHz (L band) and 6.0 GHz (C band) from matching resolution (≈3 arcsec) data. We also present catalogues of X-ray sources from Chandra data sets for 27 of the galaxies. The sources at the two radio frequency bands were positionally cross-correlated with each other, and the result cross-correlated with the X-ray sources. All catalogues are included for download with this paper. We detect a total of 2507 sources at L band and 1413 sources at C band. 75 sources have been successfully cross-correlated in both radio bands plus X-ray. Three new nuclear sources are candidates for low luminosity active galactic nuclei in NGC 3877, NGC 4192, and NGC 5792; the one in NGC 3877 also appears to be variable. We also find new nuclear sources in two companion galaxies: NGC 4435 (companion to NGC 4438) and NGC 4298 (companion to NGC 4302). We have also discovered what appears to be a foreground double star; each star has X-ray emission and there is radio emission at both L band and C band in between them. This could be a colliding wind binary system. Suggestions for follow-up studies are offered.

 

We present the ${\rm H}\, {\small I}$ distribution of galaxies from the Continuum Haloes in Nearby Galaxies – an EVLA Survey (CHANG-ES). Though the observational mode was not optimized for detecting ${\rm H}\, {\small I}$, we successfully produce ${\rm H}\, {\small I}$ cubes for 19 galaxies. The moment-0 maps from this work are available on CHANG-ES data release website (i.e. https://www.queensu.ca/changes). Our sample is dominated by star-forming, ${\rm H}\, {\small I}$-rich galaxies at distances from 6.27 to 34.1 Mpc. ${\rm H}\, {\small I}$ interferometric images on two of these galaxies (NGC 5792 and UGC 10288) are presented here for the first time, while 12 of our remaining sample galaxies now have better ${\rm H}\, {\small I}$ spatial resolutions and/or sensitivities of intensity maps than those in existing publications. We characterize the average scale heights of the ${\rm H}\, {\small I}$ distributions for a subset of most inclined galaxies (inclination > 80 deg), and compare them to the radio continuum intensity scale heights, which have been derived in a similar way. The two types of scale heights are well correlated, with similar dependence on disc radial extension and star formation rate surface density but different dependence on mass surface density. This result indicates that the vertical distribution of the two components may be governed by similar fundamental physics but with subtle differences.

 

ABSTRACT Odd radio circles (ORCs) are recently-discovered faint diffuse circles of radio emission, of unknown cause, surrounding galaxies at moderate redshift (z ∼ 0.2 – 0.6). Here, we present detailed new MeerKAT radio images at 1284 MHz of the first ORC, originally discovered with the Australian Square Kilometre Array Pathfinder, with higher resolution (6 arcsec) and sensitivity (∼ 2.4 μJy/beam). In addition to the new images, which reveal a complex internal structure consisting of multiple arcs, we also present polarization and spectral index maps. Based on these new data, we consider potential mechanisms that may generate the ORCs. 

Abstract We have found a class of circular radio objects in the Evolutionary Map of the Universe Pilot Survey, using the Australian Square Kilometre Array Pathfinder telescope. The objects appear in radio images as circular edge-brightened discs, about one arcmin diameter, that are unlike other objects previously reported in the literature. We explore several possible mechanisms that might cause these objects, but none seems to be a compelling explanation.