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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A 10-arcmin field around the HDF(N) contains 92 radio sources >40 uJy,resolved by MERLIN+VLA at 0".2-2".0 resolution. 55 have Chandra X-raycounterparts including 18 with a hard X-ray photon index and high luminositycharacteristic of a type-II (obscured) AGN. >70% of the radio sources have beenclassified as starbursts or AGN using radio morphologies, spectral indices andcomparisons with optical appearance and MIR emission. Starbursts outnumberradio AGN 3:1. This study extends the VO methods previously used to identifyX-ray-selected obscured type-II AGN to investigate whether very luminous radioand X-ray emission originates from different phenomena in the same galaxy. Thehigh-redshift starbursts have typical sizes of 5--10 kpc and star formationrates of ~1000 Msun/yr. There is no correlation between radio and X-rayluminosities nor spectral indices at z>~1.3. ~70% of both the radio-selectedAGN and the starburst samples were detected by Chandra. The X-ray luminosityindicates the presence of an AGN in at least half of the 45 cross-matched radiostarbursts, of which 11 are type-II AGN including 7 at z>1.5. This distributionoverlaps closely with the X-ray detected radio sources which were also detectedby SCUBA. Stacked 1.4-GHz emission at the positions of radio-faint X-raysources is correlated with X-ray hardness. Most extended radio starbursts atz>1.3 host X-ray selected obscured AGN. Radio emission from most of theseultra-luminous objects is dominated by star formation but it contributes lessthan 1/3 of their X-ray luminosity. Our results support the inferences fromSCUBA and IR data, that at z>1.5, star formation is an order of magnitude moreextended and more copious, it is closely linked to AGN activity and it istriggered differently, compared with star formation at lower redshifts.

Using VO tools to investigate distant radio starbursts hosting obscured AGN in the HDF(N) region