English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present Swift observations of 31 sources from the SMS4 catalog, a sampleof 137 bright radio sources in the Southern Hemisphere. All these sources hadno Chandra or XMM-Newton observations: 24 of these were observed with Swiftthrough a dedicated proposal in 2015, and data for the remaining seven wereretrieved from the Swift archive. The reduction and analysis of data collectedby the Swift X-ray Telescope (XRT) led to 20 detections in the 0.3--10 keVband. We provide details of the X-ray emission in this band for these 20detections, as well as upper limits for the remaining 11 SMS4 sources. Whenstatistics allowed, we investigated the extent of the X-ray emission, thehardness ratio, and we carried out a spectral analysis. We matched the 20 X-raydetected sources with infrared (AllWISE, CatWISE2020) and optical (GSC 2.3.2,DES DR2) catalogs to establish associations with infrared and optical sources,and compared our results with previously published counterparts in these bands.Requiring a detection in both the infrared and the optical bands to establish acandidate counterpart for our X-ray detections, we obtain reliable counterpartsfor 18 sources, while the remaining two sources need further investigation toestablish firm identifications. We find that ~35% of all the SMS4 sources liebelow the lower limit of 10.9 Jy for the flux density at 178 MHz. We presentthe list of 56 SMS4 sources that in 2022 March remain to be observed in theX-rays with narrow-field instruments.

A Swift X-ray view of the SMS4 sample -- X-ray properties of 31 quasars and radio galaxies