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 present a very deep near-infrared spectroscopic observation of a strongLy_alpha emitter at z=6.33, SDF J132440.6+273607, which we used to search forHeII 1640. This emission line is expected if the target hosts a significantnumber of population III stars. Even after 42 ksec of integration with theSubaru/OHS spectrograph, no emission-line features are detected in the JH band,which confirms that SDF J132440.6+273607 is neither an active galactic nucleusnor a low-$z$ emission-line object. We obtained a 2sigma upper-limit of9.06e-18 ergs/s/cm^2 on the HeII 1640 emission line flux, which corresponds toa luminosity of 4.11e42 ergs/s. This upper-limit on the HeII 1640 luminosityimplies that the upper limit on population III star-formation rate is in therange 4.9--41.2 M_sun/yr if population III stars suffer no mass loss, and inthe range 1.8--13.2 M_sun/yr if strong mass loss is present. The non-detectionof HeII in SDF J132440.6+273607 at z=6.33 may thus disfavor weak feedbackmodels for population III stars.Comment: 13 pages, 3 figures, to appear in The Astrophysical Journal Letter

An Observational Pursuit for Population III Stars in a Lyα Emitter at z = 6.33 through He ii Emission