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 report the results of deep (4.6h) H band spectroscopy of the well studiedz~12 H-band dropout galaxy candidate UDFj-39546284 with MOSFIRE on Keck-I.These data reach a sensitivity of 5-10 x 10^-19 erg s^-1 cm^-2 per 4.4 Angstromresolution element between sky lines. Previous papers have argued this sourcecould either be a large equivalent width line emitting galaxy at 2<z<3.5 or aluminous galaxy at z~12. We find a 2.2 sigma peak associated with a linecandidate in deep Hubble-Space-Telescope Wide-Field-Camera 3 Infrared grismobservations, but at a lower flux than what was expected. After consideringseveral possibilities we conclude these data can not conclusively confirm orreject the previous line detection, and significantly deeper spectroscopicobservations are required. We also search for low-redshift emission lines inten other 7<z<10 z, Y, and J-dropout candidates in our mask and find nosignificant detections.

Keck-I MOSFIRE spectroscopy of the z~12 candidate galaxy UDFj-39546284