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

We identify a population of 640 obscured and 839 unobscured AGNs at redshifts0.7<z<~3 using multiwavelength observations of the 9 deg^2 NOAO Deep Wide-FieldSurvey (NDWFS) region in Bootes. We select AGNs on the basis of Spitzer IRACcolors obtained by the IRAC Shallow Survey. Redshifts are obtained from opticalspectroscopy or photometric redshift estimators. We classify the IR-selectedAGNs as IRAGN 1 (unobscured) and IRAGN 2 (obscured) using a simple criterionbased on the observed optical to mid-IR color, with a selection boundary ofR-[4.5]=6.1, where R and [4.5] are the Vega magnitudes in the R and IRAC 4.5micron bands, respectively. We verify this selection using X-ray stackinganalyses with data from the Chandra XBootes survey, as well as opticalphotometry from NDWFS and spectroscopy from MMT/AGES. We show that (1) thesesources are indeed AGNs, and (2) the optical/IR color selection separatesobscured sources (with average N_H~3x10^22 cm^-2 obtained from X-ray hardnessratios, and optical colors and morphologies typical of galaxies) and unobscuredsources (with no X-ray absorption, and quasar colors and morphologies), with areliability of >~80%. The observed numbers of IRAGNs are comparable topredictions from previous X-ray, optical, and IR luminosity functions, for thegiven redshifts and IRAC flux limits. We observe a bimodal distribution inR-[4.5] color, suggesting that luminous IR-selected AGNs have either low orsignificant dust extinction, which may have implications for models of AGNobscuration.

A large population of mid-infrared selected, obscured active galaxies in the Bootes field