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

The extragalactic gamma-ray sky is dominated by the emission arising fromblazars, one of the most peculiar classes of radio-loud active galaxies. Sincethe launch of Fermi several methods were developed to search for blazars aspotential counterparts of unidentified gamma-ray sources (UGSs). To confirm thenature of the selected candidates, optical spectroscopic observations arenecessary. In 2013 we started a spectroscopic campaign to investigate gamma-rayblazar candidates selected according to different procedures. The main goals ofour campaign are: 1) to confirm the nature of these candidates, and 2) wheneverpossible determine their redshifts. Optical spectroscopic observations willalso permit us to verify the robustness of the proposed associations and checkfor the presence of possible source class contaminants to our counterpartselection. This paper reports the results of observations carried out in 2014in the Northern hemisphere with Kitt Peak National Observatory (KPNO) and inthe Southern hemisphere with the Southern Astrophysical Research (SOAR)telescopes. We also report three sources observed with the Magellan and Palomartelescopes. Our selection of blazar-like sources that could be potentialcounterparts of UGSs is based on their peculiar IR colors and on theircombination with radio observations both at high and low frequencies (i.e.,above and below ~ 1 GHz) in publicly available large radio surveys. We presentthe optical spectra of 27 objects. [....] We also report the case for WISEJ173052.85-035247.2, candidate counterpart of the source 2FGL J1730.6-0353,which has no radio counterpart in the major radio surveys. We confirm that ourselection of gamma-ray blazars candidates can successfully indentify low-energycounterparts to Fermi unassociated sources and allow us to discover newblazars.

Optical spectroscopic observations of gamma-ray blazar candidates IV. Results of the 2014 follow-up campaign